Genetics Comprehensive Exam
Mediator
A protein complex that mediates between RNA pol II and the regulatory transcription factors
The nucleic acid genome of a virus may be
Circular or linear, DNA or RNA, double stranded or single stranded, a few thousand or more than 100,000 nucleotides
Bacterial chromosomes are
Circular, double stranded DNA and compacted into a nucleoid
Shell coiling in the water snail lymnaea is due to
Maternal effect inheritance
Tropomyosin plays a role in
Muscle contraction
HOX genes determine
The fate of each segment. Proteins activate the genes to make a specific body part. Trans acting
Linkage map
A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes
An individual with somatic cells that are genotypically different from each is called
A genetic mosaic
A gamete
A haploid reproductive cell
Genomic imprinting may involve
A single gene, a part of a chromosome, an entire chromosome, even all the chromosomes from one parent
Allele E1 encodes
An enzyme that functions better at lower temperatures
Double stranded RNA has a molecular signature associated with viruses
Can cause activation of anti-viral defense mechanisms
16S rRNA plays a key rold in codon-anticodon recognition
Can detect an incorrect tRNA bound at the A site. Prevents elongation until mispaired tRNA is released
DNA southern blots
Can detect the presence of a particular gene sequence within a mixture of many
Neutral mutation
Does not alter protein function
Silent mutations
Doesn't alter amino acids
Histone acetyltransferase
Enzymes which acetylate the positively charged lysines within the core histone proteins
Three types of dominant mutant alleles
Gain of function mutations, dominant negative mutations, haplo insufficiency
Studying regulatory elements traditionally uses enzymes
Galactosidase and glucuronidase
Recombinants
Gametes that carry a new combination of alleles
Sanger sequencing
DNA polymerase adds ddNTPS to the 3'OH end. There is no more 3'OH end so the reaction is cut off because there's no exposed O to attach more
CpG islands
DNA regions rich in C residues adjacent to G residues. Especially abundant in promoters, these regions are where methylation of cytosine usually occurs
DNA pol II, IV, V are involved in
DNA repair and replication of damaged DNA
Telomerase RNA functional role
DNA replication
3 classes of segmentation genes
Gap, pair rule, and segment polarity
Homologous recombination can lead to
Gene conversion
Mechanisms of gene redundancy
Gene duplication creates similar genes or paralogs. Genes may be involved in similar cell function
Gain of function mutations (dominant allele)
Gene gains a new or abnormal function. May be overexpressed, producing higher levels of the protein
Point mutation
Gene mutation in which a single base pair in DNA has been changed
X-chromsome ianctivation
In each cell of the earl embryo, one X chromosome becomes a Barr body
Operons involved in catabolism are typically
Inducible. The substance to be broken down acts as the indcuer
Likely effect on protein function in frameshift mutation
Inhibitory
Likely effect on protein function in nonsense mutation
Inhibitory
Translation can be viewed as occuring in three stages
Initiation, elongation, and termination
Copia elements demonstrate regulatory effects at the point of
Insertion in the chromosome
Biological significance of imprinting
Not well understood
Alignment identifies
Overlapping sequences, allowing reconstruction of their order in a chromosome
Minor contamination of sample DNA can cause major problems in
PCR
Deamination
Removal of an amino group from cytosine base resulting in uracil. May be corrected, may result in deaminate 5 methyl cytosine resulting in thymine (hot spot for mutation)
Alloploidy
Polyploid organism that contains the genomes of two or more different species. Interspecies cross
Deletion
Portion of chromosome is missing
Duplication
Portion of chromosome is repeated
Chromosome structure alteration: duplication
Portion of the chromosome is repeated
Coupling RT with PCR
Semiquantitative allows user to compare expression of genes between two samples
Simple mendelian inheritance describes inheritance patterns that obey
The law of segregation and the law of independent assortment
Insertion of P elements into the promoter can affect
The level of gene expression
The 23S rRNA is the component of the 50S subunit that acts as
The peptidyl transferase
mRNA transcription terminates when the 3' end dissociates after
The poly-A signal sequence
I on the lac operon is
Trans acting
ncRNA molecules involved with translation
tRNA, rRNA, antisense RNA
Codons are recognices by the anticodon of
tRNAs
The 3D structure of release factors mimics
tRNAs
ncRNAs and miRNA processing components may be effective targets for novel treatment therapies
Therapies that inhibit miRNA function or therapies that restore miRNA function
Steroid hormones are lipids
They can pass through plasma membrane
Sex limited traits
Traits that occur in only one of the two sexes. Responsible for sexual dimorphism. May be autosomal or sex linked
The action of the lac repressor on the lac operon is a
Trans acting factor
RNA polymerase II in eukaryote transcription
Transcribes all proetin encoding genes. Responsible for the synthesis of all mRNAs
RNA pol II
Transcribes all protein encoding genes, thus synthesizes all mRNAs. Transcribes some snRNA genes
RNA polymerase II in transcription
Transcribes protein encoding genes
Negative regulation: no repressor
Transcription
No proofreading in
Transcription
There is rho independent and rho dependent termination in
Transcription
The biological advantage of alternatice splicing is that
Two or more polypeptides can be derived from a single gene
RNA northern blotting
Used to identify specific RNAs within a mixture of many RNA molecules. Similar to DNA blotting
Spreading in X inactivation
Xist expressed on chromosome to be inactivated, Xist transcripts coat chromosome, proteins recruited to chromosome to condense it
Different species can be distinguished from each other based on the number and size of
Chromosomes
Genomic library
Composed of chromosomal DNA fragments. Should represent all of the DNA of the cell
Promoter in bacteria
Consists of -35 and -10 sequences
Unregulated gene expression
Constitutive (constant). Essentially constant levels of expression. Frequently for proteins that are continuously necessary for the survival of the organism
Cetromere
Constricted region of the chromosome, which has a role in chromosome segregation during mitosis and meiosis
miR-1 is associated with the development of
Heart arrhythmias (irregularities in the rate or rhythm of the heartbeat). Regulates expression of genes that encode ion channel proteins, which are important for proper signaling between cardiac muscle cells
Variable characteristics of pea plants
Height, flower color, flower position, seed color and shape, pod color and shape
Keto tautomeric shift
Enol form (lose H) T and G
Occasionally, whether a mutation is beneficial or deleterious will depend on
Environmental conditions
What determines exit from latency?
Environmental conditions
The epigenome is cell type specific and changes throughout the life cycle in response to
Environmental cues
Maternal imprinted
Father's allele is expressed
Transmission patterns for X linked genes
Fathers transmit X only to daughters, and sons receive their X only from their mothers
Control of protein function in posttranslational regulation can occur by
Feedback inhibition or covalent modification of amino acids in the protein
Homogametic sex
Female that is X-X. All eggs carry X plus 22 autosomes
Alloploidy plants may undergo nondisjunction and produce
Fertile offspring
Nuclear lamina
Fibers lining the inner membrane
Mechanism of RNAi
First pri-miRNA is made which forms a hairpin. Cleaved to 70 nucleotide pre-miRNA and exported from the nucleus to the cytoplasm where it's cut by DICER to 20-25bp
Initiation in eukaryotes
Five general transcription factors assemble at the core promoter
Simple transposons
Flanking direct repeats, inverted repeats, transposase gene. Carry one or more genes not necessary for transposition
Key enzymes
Histone acetyltranferase/histone deacetylase. Histone methyltransferase/histone demethylase
HOTAIR is transcribed from the opposite (antisense) strand with respect to the
HoxC genes
Each chromosome carries
Hundreds of thousands of different genes
Types of product that comes out of a DNA ligation
Insert DNA ligated to itself, empty plasmid, plasmid with an insert
Insertions and deletions in coding regions for proteins can
Insert new amino acids or cause a shift in the reading frame
mRNAs have different
Molecular weights
When morgan studied flies and found X linked traits
Mostly combinations of traits like the parents meaning that all three genes observed are located on the X chromosome and transmitted together as a unit
In myotonic muscular dystrophy, the TRNE is more likely to occur if inherited from the
Mother
Genetic material replication
Must be copied to be passed from parent to offspring
Some genes do not encode polypeptides but are transcribed into
Non coding RNAs (ncRNAs)
Nonhomologous end joining
Occrus at the double strand breaks. The broken ends are recognized by proteins that keep the ends together; the broken ends are eventually rejoined
Some human aneuploidies are influenced by parental age
Older parents more likely to produce abnormal offspring
Specific pattern of splicing involved proteins known as
Splicing factors. Play a key role in determining splice sites
Homologous recombination repair
Strand of normal sister chromatid is used to repair damaged sister chromatid
The length of telomeres is maintained using the enzyme
Telomerase
In the formation of haploid cells
Chromosomes segregate independently
Human mitochondrial diseases are typically
Chronic degenerative disorders affecting cells that need high levels of ATP: nerve and muscle cells
P and O are components of the lac operon that are
Cis acting
Lac operator is a
Cis acting element
Factors that control gene expression can be divided into two types based on their location
Cis acting elements and trans acting factors
Restriction enzymes bind to specific DNA sequences and
Cleave the phosphodiester backbone of the DNA at defined locations on each strand
cDNA pros and cons
Clone abundance equals the percent of mRNA transcript in starting tissue. No introns or promoters. Less junk
DNA amplification used to study DNA
Cloning vectors-DNA replication in cells and amplification in vitro-thermostable DNA polymerases
Plasmid
A small ring of DNA that carries accessory genes separate from those of the bacterial chromosome
Oligonucleotide with reporter at one end, quencher at the other
Complementary to the PCR product
Chromosome structure alteration: deletion
AKA deficiency. Portion of chromosome is missing
Adaptation of CRISPR defense
AKA spacer acquisition. Cas1 and 2 protein complex cleaves bacteriophage DNA and a piece of this is inserted into the spacer region of the Crispr gene
Deletion/insertion
Addition or removal of bases
The first amino acid in a polypeptide chain has an exposed
Amino group; N-terminus or amino terminal end
Tn elements
Can introduce multi-drug resistance onto bacterial plasmids (R factors)
Isoacceptor tRNAs
Can recognize the same codon
In both plants and animals, the action of transcription factors depends on
Changes in chromatin structure, making genes available for expression
Aneuploidy
Changes in chromosome nu,ber
qPCR uses a thermocycler that can measure
Changes in fluorescence from detector molecules
Transcriptional activation in eukaryotes involves
Changes in nucleosome locations, nucleosome composition, and histone modifications
What affects the degree of chromatin compaction during the life cycle of the cell?
Changes in the proteins
Mutagenic agents are usually classified as
Chemical or physical mutagens
Histone modification alter
Chromatin conformation and protein interactions with the DNA strand
Plasmids exist independently of
Chromosomal DNA
Three alleles affect the sugar addition in ABO blood type genes
i allele, IA, IB
Presence of the Xist transcript on the Xi chromosome results in the recruitment of
macroH2A
Nonpolar amino acids are hydrophobic
They are often buried within the interior of folded protein
Linked assortment
Variants found together in parents are always inherited as a unit
eIF
Eukaryotic initiation factors
Evo-devo
A field that combines evolutionary and developmental biology
Haplodiploid sex determination is found in
Bees, wasps, and ants
Coupling RT with qPCR
Can numerically estimate the difference in expression
Causes of mutations
Can occur spontaneously or be induced
The 7-methylguanoisine cap structure is recognized by
Cap binding proteins
RNA interference is transcribed from
Endogenous eukaryotic genes
RNA interference is a major mechanism of
Gene expression regulation in eukaryotes
By the end of prophase, sister chromatids are entirely
Heterochromatic
Chromatin can be 2 forms
Heterochromatin or euchromatin
Base pairs per turn of the helix
10
TFIID
A general transcription factor that recruits RNA pol to the promoter
Gene sry
A single gene on the Y chromosome that is responsible for male development
Alleles
Different versions of the same gene
Homeotic selector
Hox genes specify the fate of each segment
Different types of transposable elements have
Characteristic DNA sequences
Beta clamps
Keeps pol III attached to DNA
Character
Characteristics that can vary such as height
Germ line mutation
Mutation that can be passed onto offspring
Template DNA in PCR
Contains the region that needs to be amplified
Allosteric enzyme
Contains two different binding sites
In huntington's disease, the TRNE is more likely to occur if inherited from the
Father
Examples of nucleotides
AMP, ATP, ADP
The predominant form of double helix found in living cells
B DNA
Inhibitors
Bind activators and prevent them from binding to DNA
Denaturation in PCR
DNA strands separated
lacZ gene
Encodes beta-galactosidase
Pair rule mutations
Every other segment deleted
Smaller things move through thick substances
Faster than larger things
Mutation most likely to cause phenotype
Frameshift mutation
Mutagens are often involved in the development of
Human cancers
DNA ligase
Joinds fragments together
Capsid
Outer protein coat of a virus
Original DNA strands
Parental strands
Chaperones
Proteins that help folding
The ribosome is a ribozyme
RNA acts as an enzyme
Telomere sequence for humans
TTAGGG
tRNAs are named according to
The amino acid they bear
The nuclear matrix organizes
The chromosomes within the nucleus
Wild type
The relatively prevalent genotype
Blotting uses a probe
To visualize
RF1 recognizes
UAA and UAG
If ncRNAs are expressed abnormally
Disease conditions can occur
When exposed to both lactose and glucose
E. coli uses glucose first, and catabolte repression prevents the use of lactose. When glucose is depleted, catabolite repression is alleviated and the lac operon is expressed
TFIID
A complec of proteins that includes the TATA binding protein (TBP) and several TBP associated factors
Trisomy
A condition in which an extra copy of a chromosome is present in the cell nuclei, causing developmental abnormalities
The homeodomain
A conserved sequence of 60 amino acids used in the binding to DNA. Usually found in transcription factors, it is used to express genes that are related, more specifically in development to make tissues associated with one another.
Barr body
A dense body formed from a deactivated X chromosome.
Nucleosomes associate with each other to form
A more compact structure 30nm fiber
In deamination, if repair system fails to correct the problem
A mutation could result during subsequent round of DNA replication
Apurinic sites can be repaired, but if the repair system fails
A mutation may result
Somatic mutation
A mutation that cannot be passed onto the offspring
Neutral mutation
A mutation that has no effect on the organism. Does not alter protein function
ncRNA scaffold
A ncRNA binds a group of proteins
ncRNA guide
A ncRNA binds to a protein and guides it to a specific site in the cell
Alteration of protein function or stability by ncRNA
A ncRNA can bind to a protein and alter the proteins structure, ability of the protein to act as a catalyst, to bind to another molecule, change protein stability
Genes that play a role in disease may exist as
A normal allele or a mutant allele that causes disease symptoms
A gene is called recessive if the heterozygote has
A normal phenotype. One wild type copy is sufficient to provide full function
The chromosome theory of inheritance confirmed that
A particular gene was localized to a chromosome
Conjugation bridge
A passageway for the transfer of the genetic information from the F+ to the F-
Nucleotides are covalently linked by
A phosphodiester bond
Relaxosome
A protein complex that recognizes the origin of transfer in F factors and other conjugative plasmids, cuts one DNA strand, and aids in the transfer of the T DNA
Base analogs
A purine or pyrimidine that differs in chemical structure from those normally found in DNA or RNA. Can substitute for purines or pyrimidines during nucleic acid replication
A transversion is a change of
A pyrimidine to a purine or vice versa
Mechanism of counting X chromosomes in cells relies on
A region of the X chromosome called the X inactivation center (Xic)
Repressor
A regulatory protein that binds to the DNA and inhibits transcription
Activator
A regulatory protein that increases the rate of transcription
An operon
A regulatory unit consisting of a few structural genes under the control of one promoter
The number of recombinants are used to calculate
A relative distance between the genes
The core promoter
A relatively short DNA sequence that is necessary for transcription to take place. Consists of TATA box and the transcriptional start site
Allopolyploids can mutate again to regain fertility
A second defective cell division can turn them into fertile polyploids which produce diploid gametes
Suppressor mutations
A second mutation that affects phenotypic expression of the first mutation
Suppressor
A secondary mutation that can cancel the effect of a primary mutation, resulting in a wild-type phenotype. Different than a reversion-occurs at a second site
Polymerase chain reaction
A way to make many copies of a particular DNA sequence
5' and 3' UTR
Affects stability of RNA and/or translation
Mutations generate
Allelic variations
RNaseMRP
An RNA protein complex involved in processing some rRNAs, mRNAs, and mitochondrial RNAs
Autosomes
Any chromosome that is not a sex chromosome
Formation of RNA flaps
DNA pol delta elongates an okazaki fragment until it runs into the RNA primer of the adjacent fragment, causing the RNA to form a small flap
Cis-acting elements
DNA sequences in the vicinity of the structural portion of a gene that are required for gene expression. On the same DNA strand that allows binding of transcription factors
Cis regulatory elements
DNA sequences on the same DNA strand as the gene they regulate
Small RNAs in prokaryotes
CRISPR
Photolyase in direct repair
Can repair thymine dimers. Splits the dimers, restoring the DNA to original condition. Uses light called photoreactivation
Insertion of P elements into the coding region of a gene
Can terminate transcription destroying normal gene expression
Auxotrophs
Cannot synthesize a needed nutrient
mRNA modification
Capped, spliced, polyadenylated
Each capsid is made of identical protein subunits called
Capsomers
Last amino acid on a polypeptide chain has an exposed
Carboxyl group: C-terminus or carboxy terminal end
Inside to outside of flower
Carpel, stamen, petal, sepal
MADS box floral homeotic transcription factor genes (A, B, C) control the development of
Carpel, stamen, petal, sepal
The initiator tRNA is designated tRNA met
Carries a methionine rather tna a formylmethionine
tRNA involved in protein synthesis
Carry amino acids
Peptidyl transferase
Catalyzes the peptidyl transfer reaction. Where the polypeptide in the P site is transferred to the amino acid at the A site, forming a peptide bond
Viral reproduction uses reverse transcriptase to
Copy RNA into DNA for integration. Once integrated, the genome is called a provirus
Attenuation occurs in bacteria because of
Coupling of transcription and translation
DNA ligase
Covalently links the DNA backbones
Base modifiers
Covalently modify nucleotide structure
Base modifiers
Covalently modify nucleotide structure. Ex: nitrous acid replaces amino groups with keto groups
Parts of the operon
Promoter, CAP site, operator, protein coding genes, terminator
All three splicing mechanisms involve
Removal of intron RNA and linkage of the exon RNAs by a phosphodiester bond
RNA polymerase moves along the template strand in a 3' to 5' direction
RNAis synthesized in a 5' to 3' direction
DICER
Recognized double stranded RNA and cuts in into short double stranded pieces
Nucleotide excision repair
Recognizes DNA damage and remove several to many nucleotides
Filters are placed into a buffered solution containing a primary antibody
Recognizes the protein of interest but usually lacks a label
The tRNAs play a direct role in recognition of codons in mRNA
Recognizing a 3base codon in mRNA and carrying an amino acid that is specific for that codon
Genes regulated by small effector molecules that inhibit transcription are called
Repressible genes
Operons involved in anabolism are typically
Repressible. The inhibitor or corerpressor is the small molecule that is the product of the operon
trp repressor protein
Repression is achieved when the amino acid tryptophan binds to the repressor protein. The complex then binds the operator region to block transcription
Regulatory protein that decrease the rate of transcription are termed
Repressor sequences and they bind to silencer elements
Corepressors bind to
Repressors and cause them to bind to DNA
Activator proteins enhance the function of TFIID
Recruit TFIID to the TATA box or help it recruit RNA pol II, or interact with coactivators that act on TFIID
Activator proteins: aid TFIID
Recruitment to TATA box. Aids in recruiting RNA polymerase. Interact with coactivators
Silencers
Reduce transcription
Outcome of a HOTAIR ncRNA that could no longer binds to PRC2
Reduced methylation of H3K27 and possible upregulation of transcription of target genes
Enzymes are only one category of proteins
Some genes encode other types of proteins
rRNA modification
Spacer regions removed to produce 3 functional fragments
The degree of splicing and alternative splicing varies greatly among
Species
Zygotic genes: Homeotic selector (HOX) genes
Specify the fate of each segment
A single bacterial cell usually takes up a single copy of
The hybrid vector
Studying regulatory elements now usually fluorescent proteins
Either on their own or as fusion proteins
Proteins can be transferred from gels to membrane by
Electrophoresis
Col plasmids
Encode colicins, proteins that kill other bacteria
Main function of genetic material is to
Encode for the production of cellular ptoeins
IA alleles in ABO blood type
Encodes a form of the enzyme that can add the sugar N-acetylgalactosamine to the carbohydrate tree (makes A anitgen)
IB alleles in ABO blood type
Encodes a form of the enzyme that can add the sugar galactose to the carbohydrate tree (makes B atigen)
trpL
Encodes a short peptide termed the leader peptide
lacY
Encodes lactose permease. Membrane protein required for transport of lactose and analogues into the cell
lacA
Encodes transacetylsae. Covalently modifies lactose and analogues. Its functional necessity remains unclear
Steroid hormones are produced by
Endocrine glands
Diploid animals sometimes produce tissues that are polyploid
Endopolyploidy. Liver cells can be triploid, tetraploud, or even octaploid
TFIID and TFIIB recognize promoter region in
Eukaryotes
The recessive trait disappears entirely in the
F1 but reappears unchanged in the F2
Primase
Synthesizes the RNA primers
Genetic variation results from changes at
The molecular level
Meiotic non disjunction
Failure of chromosomes to segregate properly in anaphase. Can occur in meiosis I or II. Can produce cells with too many or few chromosomes and creates zygotes with abnormal chromosome numbers.
In eukaryotes RNA primers are removed by
Flap endonuclease
Intercalating agents contain
Flat planar structure that intercalate into the double helix
Most mitichondrial proteins are encoded by genes in
The nucleus. Proteins are made in the cytoplasm but have signal to direct them to
Eukaryotic replication begins with assembly of
The pre-replication complex (preRC)
Linkage refers to
Genes that are generally transmitted together
MutL, MutH, and MutS
Genes that detect mismatch and direct its removal from the newly made strand
Two categories of genes are associated with ncRNAs and neurological disorders
Genes that encode miRNAs and genes that encode proteins involved in processing miRNAs
Trans acting factors mediated by
Genes that encode regulatory proteins
Sex linked genes
Genes unique to X or Y
Multiple alleles
Genes with three or more alleles rather than the standard two. Exhibit codominance (both alleles are expressed)
Deleterious mutation
Genetic changes that are harmful to an organism. Lowers the chance of survival and reproduction. Good for studying genetics
Trans effect or trans acting factor
Genetic regulation that can occur even though DNA segments are not physically adjacent
Suppressor can be reversion in phenotype but not
Genetically because it's happening in a second gene
An epitote
Has a 3D structure that an antibody recognizes
Temperate phage
Has both latent and lysogenic cycles
Virulent phage
Has only a lytic cycle. Not capable of integration into the genome
Homologous genes are best described as genes that
Have a common ancestral gene
Libraries aim to
Have clones of all pieces of DNA in a genome (genomic library) or expressed in a tissue (cDNA library)
Polymorphism
In large populations, there may be more than one common allele considered to be wild type. This is known as genetic polymorphism
Pre-mRNA can be spliced
In more than one way
Reciprocal translocations are usually without phenotypic consequences
In some cases they can result in position effect
The RNA transcript is synthesized during the elongation step
In the 5' to 3' direction. Phosphodiester bonds are formed between the ribonucleotides
Monoallelic expression
In the case of imprinting, refers to the phenomenon that only one of the two alleles of a given gene is transcriptionally expressed
Artificial transformation
In transformation when DNA uptake occurs with the help of special techniques
ddNTPs
Lack a hydroxyl group
Inheritance patterns that deviate from Mendels law are seen when one allele is
Lethal
Semi lethal alleles
Lethal in some
Structure and number of chromosomes are typically studied by
Light microscopy
Some areas of the chromosome have a lower change of crossing over
Like near the centromere
Mutation rate
Likelihood that a gene will be altered by a mutation
Mutation rate
Likelihood that a gene will be altered by a mutation. Commonly expressed as the number of new mutations in a given gene/cell generation
Deleterious mutation
Lowers chance of survival and reproduction
Three natural mechanisms by which the chromosome number of a species can vary
Meiotic nondisjunction, mitotic nondisjunction, allploidy (interspecies crosses)
3 classes of cellular RNAs directly involved in protein synthesis
Messenger RNA, ribosomal RNA, transfer RNA
Chromatin structure is modified through
MethylCpG-binding protein which recruits other proteins, such as histone deacetylase, that modify the chromatin leading to a closed conformation
DNA methylation is heritable
Methylated DNA sequences are inherited during cell division
At least some genes are silenced on inactive X chromosomes by
Methylation
Genomic imprinting must involve a marking process that is reversible
Methylation of DNA bases
Maintenance methylation
Methylation pattern is maintained in the resulting offspring. Hemimethylated DNA is recognized by DNA methyltransferase, which makes it fully methylated
Karyotype
Microgrpah of all chromosomes in a cell (metaphase)
Endosymbiosis theory
Mitochondria and chloroplasts originated from bacteria that took up residence within a primordial eukaryotic cell
Paternal leakage
Mitochondria inherited from father via sperm
Species with maternal inheritance may, on occasion, exhibit paternal leakage
Mitochondria provided through the sperm
Heteroplasmy
Mix of wild type and mutant chloroplast or mitochondria in one cell
Second step of gene cloning
Mix the chromosomal DNA fragments with the digested vector and add DNA ligase to join them together
Transposable elements
Mobile pieces of DNA that can copy themselves into entirely new areas of the chromosomes. Can move around the genome
DNA methylation
Modifications to DNA elements or to their accessibility
In plants, sterile hybrids may be
More vigorous than the parent species and propagate asexually
Twin spot
Mosaic arising from mitotic recombination
Polyploidy can be induced by abrupt temperature changes or drugs
Most commonly the drug colchicine is used. Binds and stabilizes tubulin (a protein found in the spindle apparatus), promoting nondisjunction
Homeotic genes are activated as
Targets of the segmentation genes and determine the adult structures formed by each segment
Environmental agents can affect epigenetic regulation
Temperature, diet, toxins
A codon is always shown as the sense strand
Template DNA strand is antisense
Starting material for PCR
Template DNA, oligonucleotide primers, deoxynucleoside triphosphates (dNTPs), thermostable DNA polymerase
Tautomeric shift
Temporary change in base structure that promotoe A-C and G-T base pairing
Tautomeric shifts
Temporary change in base structure. Rare forms promote A-C and G-T base pairs that cause a mutation if it occurs immediately prior to replication
Aerobic organisms use oxygen as
Terminal electron acceptor
Stop codons
Termination or nonsense codons. (UAA, UAG, UGA)
Sex linked traits can be confirmed by
Test crosses
Synthesis of the leading strand is continuous and
That of the lagging strand is dicontinuous
A phosphate connects the 5' carbon of one nucleotide to
The 3' carbon of another nucleotide
mRNA transcription terminates when
The 3' end is cut just past the polyA signal sequence
Destabilizing elements are most common at
The 3' unsaturated region (3' UTR). The 3' end between the stop codon and the polyA tail
Polypeptide synthesis has a directionality that parallels
The 5' to 3' orientation of mRNA
A site in prokaryotic chromosome called the CRISPR locus regulates
The CRISPR-Cas system in bacteria. Contains segments that are derived from bacteriophage DNA
Primary structue of a protein
The amino acid sequence. The amino acids each have a unique side chain or R group
Leader peptide has several codons for
The amino acid whose biosynthesis is the result of the expression of the operon. If enough of the amino acid is still present, rest of operon is not expressed
Elongation in translation
The amino acids are added to the polypeptide chain, one at a time
A nucleotide deletion in DNA replication causes
The amino acids downstream from the deletion to be incorrect
Action of the maternal and segmentation genes defines
The anterior-posterior axis which is the field of action of the homeotic genes
SRP RNA provides a scaffold for
The binding of SRP proteins
Combinatorial control of transcription factors refers to the phenomenon that
The combination of many factors determines the expression of any given gene
Evolutionary mechanisms for differential development or organisms include
Mutation, gene duplication and subsequent divergence, assignment of new functions to old genes, recruitment of genes to new developmental pathways
Insertion of transposons can cause
Mutations
Several inherited limb malformations are caused by
Mutations in HOXD genes
Estimated that 1/3 of all genes are essential (required for survival)
Mutations in these genes can form lethal alleles
Random mutation theory
Mutations occur in any gene or piece of DNA randomly (although there may be hot spots). Do not need selection for mutation to occur. Growth condition may then select for most adapted organism
Start codon is AUG in some cases GUG or UUG but the first amino acid is always
N-formylmethionine
Two steps of transormation
Natural transformation and artificial transformation
Reverse transcriptase
Naturally occurring enzyme in retroviruses to copy their RNA genome to DNA
Mendel's Law of Segregation
The two copies of a gene segregate (or seperate) from each other during transmission from parent to offspring
ATs are easier to separate because of
The two hydrogen bonds instead of three
In the replisome, two DNA pol III proteins act in concert to replicate both the leading and lagging strands
The two proteins form a dimeric DNA polymerase that moves as a unit toward the replication fork
A strategy that inhibits miRNA function for treating certain cancers
The use of anti-miRNA oligonucleotides (AMOs)
When allolactose is available it binds to the repressor
This alters the conformation of the repressor protein, which prevents it from binding to the operator site. Therefore, RNA polymerase can transcribe the operon
Depending on whether a purine or phyrimidine is removed in base excision repair
This creates an apurine and apyrimidine site respectively
Nonionizing radiation
UV. Thymine dimers (crosslinked Ts)
In simple translocations the transfer of genetic material occurs in only one direction. AKA
Unbalanced translocations
Ames test
Used to determine if something is a mutagen
Recombinant analysis example
WWBB x wwbb then WwBb x wwbb
Hybridization
When plants with different traits are crossed. The result are called hybrids
Coupling between transcription and translation
When translation begins before transcription ends
Why the percentage of recombinant offspring plateaus at 50%
When two different genes are more than 50 map units apart, they follow the law of independent assortment in a testcross
DNA sequence alignments
Where similar sequences of bases are lined up for comparison
The stability of mRNA can be regulated so that its half life is shortened or lengthened
Will greatly influence the mRNA concentration and consequently gene expression
Most response elements are located
Within 200bp upstream of the promoter, but some are found at other various sites
Triple X syndrome
XXX two Barr bodies
Klinefelter syndrome
XXY one Barr body
The diploid cell from complete nondisjunction can participate in fertilization with a normal gamete
Yielding a triploid individual
The genetic material in chloroplasts
cpDNA
In eukaryotes one release factor recognizes all three stop codons
eRF1. eRF3 is also needed for termination
Therapies that restore miRNA function are needed for
miRNAs that behave like tumor suppressors
RNA interference is mediated by
microRNAs or small interfering RNAs
Crossing over produces
recombinant chromosomes, which combine DNA inherited from each parent
RNA modification
tRNA, rRNA, and mRNA are all modified
Reject null hypothesis if p value is
0.05 or less
DNA polymerases go in the direction of
5' to 3'. It requires a nucleotide primer with a free 3' -OH
DNA polymerase I
5' to 3'. Primarily acts on only the lagging strand to remove RNA primers from okazaki fragments. Uses 5'-3' polymerase activity to replace RNA with DNA
Alterations in chromosome number frequently occur during gamete formation
5-10% of embryos have an abnormal chromosome number. 50% of spontaneous abortions are due to such abnormalities
Together the nucleosomes and fiber shorten the DNA
50 fold
Amount of transposable elements in the human genome
50%
Why one wild type copy is sufficient to provide full function
50% of normal levels of protein are good enough. The one wild type copy is up regulated in expression, to produce adequate amount of functional protein
Standard gel electrophoresis can separate DNA up to
50kb. Can adjust agarose concentrations for different sizes
Origin recognition complex
6 proteins. Acts as initiator of DNA replication
ER signal sequences
6-12 amino acids. Hydrophobic and near the N terminus
Number of codons
64
In a typical human cell, only about 20% of transcription involves the production of mRNAs whereas
80% of it is associated with making ncRNAs. Ribosomal RNAs and transfer RNAs are a large part of that
Long non coding RNAs (lncRNAs)
>200 nucleotides
Inheritance patterns that deviate from Mendels law are seen when the alleles don't have
A simple dominant/recessive relationship
RNA polymerase in bacteria
A single RNA polymerase
A point mutation
A single base pair change
Gene libraries can be made from subgenomic fractions such as
A single chromosome generated by methods such as flow sorting and pulsed field gel electrophoresis
Like chloroplasts, mitochondria contain
A single circular chromosome. Contained within the nucleoid. Multiple copies of the single chromosome
The chromosome of both mitochondria and chloroplasts is composed of
A single circular double stranded DNA
Only tryptophan and methionine are encoded by
A single codon
One gene one enzyme hypothesis
A single gene controlled the synthesis of a single enzyme
Most genes can be pleiotropic
A single gene determines more than one phenotype for an organism
Polycistronic mRNA
A single molecule of messenger RNA that is formed by the transcription of a group of functionally related genes located next to one another along bacterial DNA
Viral and bacterial chromosomes
A single nucleic acid molecule, few if any associated proteins, much smaller than eukaryotic chromosomes
Apurinic site
A site in DNA that is missing a purine base
Incomplete penetrance
A situation in which an allele is expected to cause a particular phenotype, but does not in a given individual. An individual who carries a dominate allele does not show the phenotype of that allele
Inducer
A small effector molecule that causes transcription to increase
Switch from active to inactive relies on
A small molecule
Segmental duplication
A small segment of a chromosome that has a tandem duplication
Pre-mRNA introns are removed via
A splicesome
Fluorescence amounts can be compared to
A standard of known amounts of template. Different colored fluorescent molecules distinguish the test product from the standard
Intergenic suppressor
A suppressor mutation that is in a different gene from the gene that contains the first mutation. Second mutation is in a different gene than the first
In early stages of embryo development, the zygote nucleus undergoes a number of divisions without cytokines and creates
A syncytium
Genetic mapping experiments are accomplished by carrying out
A testcross
Endosymbiosis
A theorized process in which early eukaryotic cells were formed from simpler prokaryotes
In meiosis I, homologous chromosomes synapse with each other. For normal and inversion chromosomes to synapse properly
An inversion loop must form
Segregation analysis is used to follow the inheritance of traits relative to each other
Can map relative to how frequently recombination occurs between them
TEs influence on mutation and evolution
Can rapidly enter genome and proliferate. Can be a major part of genomes
Competent cells
Are able to take up naked DNA. Cells that can be transformed by extracellular DNA
tRNA modification
Are processed by exonucleases (cut at the end of a strand) and endoculeases (cut within a strand)
Centromere
Area where the chromatids of a chromosome are attached
Emerging viruses
Arose recently and are more likely to cause infection than previous strains
Active genes in eukaryotes have a nucleosome free region
Around the core promoter and the termination site
Helix is right handed
As is spirals away from you, the helix turns in a clockwise direction
RT-PCR can detect expression of small amounts of RNA in a single cell and is semi quantitative
As long as cycle number is restricted
During bacterial translation, the mRNA lies on the surface of the 30S subunit
As polypeptide is being synthesized, it exits through a hole in the 50S subunit
Multiple crossovers set a quantitative limit on measurable recombination frequencies
As the physical distance increases
Horsetail is an example of alloploidy
Asexual but successfully propagates from rhizomes
Telomere
At ends, prevent translocations and are necessary for maintenance of chromosome length
Dominant pattern of inheritance: affected individual will have
At least one affected parent. Does not skip generations
General steps of a viral reproductive cycle
Attachment, entry, integration, synthesis, viral assemble, release
The segment of trp operon immediately downstream from the operator site plays a critical role in
Attenuation
Inheritance patterns of sex linked genes are different than
Autosomal genes
Particulate theory of inheritance
A theory proposed by Mendel. it states that traits are inherited as discrete units that remain unchanged as they are passed from parent to offspring
A karyotype can be used to detect
Abnormal chromosome number or structure, but not small changes of a few to a few thousand nucleotides
Abberant recombination
Abnormal crossing over may cause deletions, duplications, translocations, and inversions
Chromosome duplication is usually caused by
Abnormal events during recombination. Called non allelic homologous recombination. Repetitive sequences can cause this
Duplication-portion of chromosome is repeated. Usually caused by
Abnormal events during recombination. Misaligned during crossing over resulting in a chromosome with a duplicated region and a chromosome with a deletion. Called non allelic homologous recombination. Repetitive sequences can cause this
Spontaneous cause of mutation
Abnormalities in cellular or biological processes. Chemical changes, oxidative stress, trinucleotide repeat expansion
Polyploidy is more common in plants
About 47-70% of plants are polyploidy. They are important in agriculture because it grows a larger and more robust plant
Number of loops in compacted chromosomal DNA varies
According to chromosome size and species
Termination in eukaryotes
According to the allosteric or torpedo model
Maternal effect is a phenomenon due to
Accumulation of gene products that the mother provides to her developing eggs
Genome size variation is not because of extra genes, it's due to
Accumulation of repetitive DNA sequences
Histones can be modified multiple ways
Acetylation, methylatin, phosphorylation
Horizontal gene transfer has dramatically contributed to the phenomenon of
Acquired antibiotic resistance
Three stages of CRISPR-Cas system
Acquisition, expression, interference
Examples of intercalating agents
Acridine dyes and proflavin
Insulator sequences that bind proteins which
Act as a barrier to chromatin or histone remodeling. Block effects of enhancers by formation of loops
Inhibitors bind to
Activators and prevent them from binding to DNA
Regulatory proteins that increase the rate of transcription are termed
Activators and the sequences they bind to are enhancer elements
Regulatory transcription factors
Activators or repressors. Serve to regulate the rate of transcription and influence the ability of RNA pol to begin transcription of a particular gene
Segment polarity genes become
Active in a band of cells that extends around the embryo's circumference to divide it
TFIIH
Acts as a helicase to form an open complex. Phosphorylates the CTD of RNA polymerase II
DNA supercoiling
Acts to further compact the chromosome using twisting forces. The loops are twisted even more
Defense mechanism of CRISPR-cas occurs in three phases
Adaptation, expression, and interference
Ion torrent/proton
Add each base one at a time and monitor release of protons. Cross between a PCR machine and a micro-pH meter. Cheap and no need to separate reaction products
Tailing in bacteria
Added to the 3' end; promotes degradation
Tailing in eukaryotes
Added to the 3' end; promotes stability
Genomic imprinting is indicated by
Addition of methyl bases
The symmetry break that occurs is due to localization of
CTCFs to one X chromosome
Mediator appears to regulate the ability of TFIIH to phosphorylate
CTD and phosphorylate the CTD itself. Plays a pivotal role in the switch between transcriptional initiation and elongation
Inheritance patters of X linked genes differ from autosomal genes
Called X linked inheritance
The mutation rate for a given gene is not constant
Can be increased by the presence of mutagens
DNA that is made from RNA is called complementary DNA (cDNA)
Can be single or double stranded
lac repressor must bind to two of the three operators to cause repression
Can bind to O1 and O2, or O1 and O3, but not O2 and O3
Southern blotting has several uses
Can determine copy number of a gene in a genome, can detect small gene deletions, can identify gene families, can identify homologous genes among different species, segregation analysis
Chain elongation occurs in the 5' to 3' direction by
Addition of one nucleotide at a time to the 3' end (-OH group). As the nucleotide is added, the 2 terminal phosphates are cleaved off
Regulatory elements/operator sites
Affects gene regulation
Example of human mitochondrial disease: LHON
Affects the optic nerve. May lead to progressive loss of vision in one or both eyes. Caused by mutations in several different mitochondrial genes
A typical PCR involves 20-35 cycles of replication
After 20 cycles, a DNA sample will increase 1 million fold, after 30 cycles, a DNA sample will increase 1 billion fold
Expression phase of crispr defense
After adaptation, exposure results in expression of crisp, tracr, and cas9 genes are transcribed and form two non coding RNAs: pre-crRNA and tracrRNA
Maternal effect gene products placed in the eff during oogensis are activated
After fertilization
Duplicated genes accumulate mutations that alter their function
After many generations, they have similar but distinct functions. They are now members of a gene family
Deamination of 5-methyl cytosine poses a problem for repair enzymes
Cannot determine which of the bases on the two DNA strands is incorrect. For this reason, methylated cytosine bases tend to create hotspots for mutation
DNA and RNA can be transferred from gels to membrane either by
Capillary transfer or electrophoresis
Cri-du-chat syndrome
Caused by a deletion in the short arm of chromosome 5
Induced cause of mutations
Caused by environmental agents (mutagens) that may be chemical or physical
Induced mutations
Caused by environmental agents. Agents known to alter DNA are called mutagens
Non coding RNAs in human disease can cause cartilage hair hypoplasia
Caused by mutation in a ncRNA which functions as a ribozyme in the RNaseMRP complex
Malaria
Caused by plasmodium, a protozoan parasite with two main parts to its life cycle: one in a mosquito and one inside red blood cells
Igf-2- is a mutant allele that makes a defective protein
Causes a mouse to be dwarf, but only if inherited from the father
siRNA can inhibit transcription by
Causing chromatin modifications
Nucleosomes are formed from the association of
Chromosomal DNA and the histone proteins
Monosomy
Chromosomal abnormality consisting of the absence of one chromosome from the normal diploid number
Monosomy
Chromosomal abnormality consisting of the absence of one chromosome from the normal diploid number (2n-1)
Reciprocal translocations arise by two different mechanisms
Chromosomal breakage and DNA repair, and non homologous crossovers
Inheritance patterns that deviate from Mendels law are seen when the genes are on the same
Chromosome
Non histone proteins bind to the linker region and aid in
Chromosome compaction and affect gene expression
Staining reveals banding patterns from
Chromosomes
Chromosome theory of inheritance
Chromosomes contain the genetic material. They're replicated and passed from parent to offspring. Nuclei of most eukaryotic cells contain chromosomes in homologous pairs. In the formation of haploid cells, chromosomes segregate independently. Each parent contributes one set of chromosomes
Inheritance patterns that deviate from Mendels law are seen when there are more than two alleles for a gene that
Controls a trait
Mediator acts to mediate the interactions between RNA pol II and regulatory transcription factors
Controls whether RNA pol II can progress to the elongation stage
Operon allows a bacterium to
Coordinately regulate a group of genes encoding proteins that are involved in a common process
DNA replication requires
Coordination with cell division, a origin of replication, DNA polymerases, accessory enzymes
Retroviruses
Copies made from provirus
Unlike chromosomes, chloroplasts are randomly distributed to
Daughter cells
DNA polymerase III synthesizes a
Daughter strand of DNA
Newly made DNA strands are
Daughter strands
Base analogs become incorporated into
Daughter strands during DNA replication. For example, a thymine analogue can be incorporated into DNA instead of thymine
Down promoter mutations
Decrease transcription. Increasing of binding of a silencing element to a negatively regulating transcription factor or removing binding site of something that will promote transcription
DNA methylation is associated with
Decreased gene expression
The binding of a transcription factor to a silencer
Decreases the rate of transcription. Down regulation
Segment polarity mutations
Defects in one side of each segment
Control of gene expression is used in multicellular organisms to
Define tissues and cells with specific functions within the organism
Expressivity
Degree at which a trait is expressed (variable). Environment may influence level of expression or modifier genes may influence phenotype
Gap gene mutations
Delete gaps in the segmentation pattern
Primary ways chromosome structure can be altered
Deletion, duplication, inversion, translocation
Duplications tend to have less harmful effects than
Deletions of comparable size
Variation in chromosome structure
Deletions/duplication, translocations (simple and recirprocal), inversions
PCR
Denaturation of the two strand of DNA, the primers hybridize and allow complementary strands to be synthesized, then elongated and repeated
Three steps of PCR
Denaturation, annealing, extension (synthesis)
Most common chemical change
Depurination
Spontaneous mutations can arise by three types of chemical changes
Depurination, deamination, and tautomeric shifts
Spontaneous chemical changes
Depurination, deamination, tautomeric shift
Norm of reaction
Describes the range of phenotypes seen across different environmental effects (for a given genotype)
Pedigree analysis is commonly used to
Determine the inheritance pattern of human genetic diseases
When deletions have a phenotypic effect they are usually
Detrimental
Many epigenetic modifications are normal parts of
Development
Transcriptional networks regulate
Development by generating patterns of gene expression. Work in cascades
Dd snail mothers produce
Dextral offspring even if the offspring are dd
Empirical approach
Didn't start with a hypothesis to explain the formation of hybrids. Believed that a quantitative analysis of crosses might reveal a mathematical relationship
Cells that do not have a vector will
Die in the presence of the antibiotic
Genetic variation
Difference in alleles and chromosomes. Can be between same or different species
Genetic variation
Differences in alleles and chromosomes, either between members of the same species or between different species
SMART sequencing
Different fluorochromes onto each base. Attached to a phosphate that is cleaved off the dNTPs and ends up in the pyrophosphate product rather than the DNA strand. Flash of light of a wavelenth specific to each fluorochrome is emitted as each base is added
Stable integration of DNA into a vector requires two steps
Digestion of vector and chromosomal DNA to create compatible DNA ends. Covalent joining or ligation of the molecules together (uses the DNA ligase used in replication)
Common types of DNA repair
Direct repair, base excision nucleotide excision repair, mismatch repair, homologous recombination repair, non homologous end joining
3 explanations for over dominance at the molecular/cellular level
Disease resistance, homodimer formation, variation in functional activity
Three explanations for overdominance at the molecular/cellular level
Disease resistance, homodimer formation, variation in functional activity
Intercalating agents
Distort helical structure causing single nucleotide additions and or deletions=frameshift
Intercalating agents
Distort the helical structure. When DNA containing these mutagens is replicated,the daughter strand may contain single nucleotide additions and/or deletions resulting in frameshifts
mRNA or protein products are placed in the developing egg/zygote by mother.
Distributed in a gradient or concentrated in specific regions. Encode proteins that regulate gene expression (transcription factors, receptors)
Maternal effect genes: mRNA or protein that moves into the developing zygote
Distributed in a gradient, encode proteins that regulate gene expression, basic positional information, trans acting
Zygotic genes: segmentation genes
Divide embryo into a series of segments (define number, size, polarity). 3 classes
Pair rule genes
Divide embryo into units of two segments each. Expressed in a series of 7 narrow bands or stripes extending around the circumference of the embryo. Activate segment polarity genes
Segment polarity genes
Divide segments into anterior and posterior regions. Control cellular identity
Initiation of replication in bacteria DNA helicase
DnaB protein and DnaC unwide DNA, separating the strands in both direction beyond the origin
Bacteria genomes have evolved so that their own DNA is modified such that the restriction enzymes that they make
Do no digest it
Nonsense codons
Do not specify an amino acud by signal stop
The trait this is exhibited in the F1 is
Dominant
A lethal allele may produce ratios that seemingly deviate from mendelian ratios. Ex: manx cats
Dominant mutation that affects the spine, mutation shortens the tail in heterozygotes, but is lethal as a homozygote
Z DNA
Double helix structure. Possible biological role in transcription and possible role in chromosome compaction
Semiconservative DNA replication
Double stranded DNA contains one parental and one daughter strand following replication
A nucleosome is composed of
Double stranded DNA wrapped around an octamer of histone proteins
An antisense RNA strand will slightly reduce mRNA but
Double stranded RNA is much better at silencing mRNA
O2 operon operator site for lac repressor
Downstream in the lacZ coding region
Allele E1 encodes an enzyme that functions better a low temps and E2 at higher temps
E1E2 heterozygotes produce both enzymes and therefore have an advantage under a wider temperature range than either E1E1 or E2E2 homozygotes
Targeting polypeptides to the ER membrane by SRP
ER signal sequence. SRP binds to signal sequence, pauses translation, binds to receptor in the ER membrane, GTP hydrolysis causes protein to pass through pore into ER and translation continues
Illumina sequencing
Each base is fluorescently labeled, all have proprietary removable terminators. One base added at a time, imaged to see which base is added, terminator is removed
There are 20 amino acids that may be found in polypeptides
Each containes a different side chain or R group
Diploid organisms have two copies of
Each gene
Dioecious plants
Each individual plant is either male or female
Complementation
Each recessive allele is complemented by a wild type allele. This indicates that the recessive alleles are in different genes
Eukaryotic species contain one or more sets of chromosomes
Each set is composed of several different linear chromosomes
Interference phase of crispr defense
Each spacer in a crRNA is complementary to one strand of the bacteriophage DNA. crRNA acts as a guide that causes the tracrRNA-crRNA-cas9 complex to bind to the strand
Expression vectors often include a leader peptide to facilitate
Easy purification of expressed proteins
Protospacer adjacent motif (PAM)
Effector complex binding site
Interference in CRISPR-Cas
Effector complex binds homologous foreing. DNA base pairing
Termination in bacter
Either rho dependent or independetn
Genomic imprinting occurs during
Gamete formation
Double recombinant
Gametes & offspring resulting from a cross over in both regions of a three point test cross
Zygotic genes
Gap genes, pair rule genes, segment polarity genes, homeotic genes
In metaphase chromosomes, the radial loops are
Highly compacted and stay anchored to a scaffold
Heterochromatin
Highly condensed (non-acetylated). Common around telomeres and centromeres. Tend to have fewer genes and lower recombination frequences
MacroH2A
Histone variant that is found along the inactive X chromosome
Whether or not genes are located on the same chromosome is going to make a difference in terms of
How they assort in meiosis
Both drosophila and arabidopsis have both
Hox and MADS box genes but their functions have diverged over evolution
Homeobox is a DNA binding domain (homeodaomain) that all
Hox genes possess
HOTAIR gene is located on
Human chromosome 12 within a cluster of HoxC genes and is a long ncRNA
Human environmental condition affecting phenotype
Humans with phenylketonuria (PKU) are unable to metabolize phenylalanine. Symptoms include mental retardation. When detected early, individuals can be fed a phenylalanine-free diet and stay healthy
Mendel mated true breeding plants with one trait to plants with a different trait to create
Hybrids
Two polynucleotide strands are held together with
Hydrogen bonding vetween the nucleotide bases
SRP RNA stimulates proteins within both SRP and the SRP receptor to
Hydrolyze GTP. SRP RNA alters the structures of these proteins
Tertiary structure of a ptoetin is determined by
Hydrophoibic and ionic interactions as well as hydrogen bonds and Van der Waals interactions
The color of bacterial colonies will depend on whether or not the B-galactosidase is function
If it is, the colonies will be blue-no insert. If not, the colonies will be white-insert present
Genomic imprinting expression depends on
If its origin is maternal or paternal. Express only the maternal or paternal allele - monoallelic expression
Wobble rule
In codon-anticodon recognition, the first two positions pair strictyl accoring to the AU/GC rule but the third position can tolerate certain mismatches
Natural transformation
In transformation. Occurs in a wide variety of bacteria. DNA uptake occurs without outside help
If a transposable element is inserted into a gene, this will likely
Inactivate the gene
Although the Tsix transcript is initially produced by both X chromosomes the Xist transcript is only produced from the
Inactive chromosome
Latency
Inactive stage of a virus integrated into the host cell genome. Called a prophage or provirus
Nonionizing radiation
Includes UV light and has less energy. Cannot penetrate deeply into biological molecules
Ionizing radiation
Includes X rays and gamma rays. Short wavelength and high energy. Penetrate deeply into biological materials and creates chemically reactive molecules termed free radicals
A heterozygote has a phenotype that is intermediate between either corresponding homozygote
Incomplete dominance
Dominant phenotype is not expressed even though an individual carries a dominant allele
Incomplete penetrance
Repeats (trinucleotide)
Increase in the number of repeats=trinucleotide repeat expansion (TNRE)
Promoters
Increase or decrease transcription
Up promoter mutations
Increase transcription. Increase binding to positively regulating transcription factors
As genes get farther apart the chance of getting two (or more) crossover events between the genes
Increases
Binding of a transcription factor to an enhancer
Increases the rate of transcription. Up regulation
During extension of PCR, the quencher is cleaved off
Increasing fluorescence
When genes are physically associated they do not
Independently assort and will not necessarily follow Mendel's law of independent assortment
Non parentals are predicted only if the genes segregate
Independently of each other
Cystic fibrosis
Individual cannot transport chloride effectively resulting in multiple phenotypes
Combination of maternal effect and gap proteins control
Individual pair rule stripe formation
Inversion heterozygotes
Individuals with one copy of a normal chromosome and one copy of an inverted chromosome
Genes that are regulated by inducers are termed
Inducible
Some viruses have specialized proteins to help
Infection. Spikes and knobs
Opportunistic infections
Infections seen in patients with compromised immune systems
Glucocorticoids
Influence metabolism in most cells
The net effect of a transcription factor is to
Influence the function of RNA polymerase
Inheritance patterns that deviate from Mendels law are seen when the trait is sex
Influenced or limited
An advantage of negative supercoiling in bacteria is that
It promotes strand separation in small regions enhancing DNA replication and transcription
DNA polymerase is processive
It stays clamped onto the DNA template strand and keeps going
A ribosome is composed of
Large and small subunits. Each is formed in the nucleolus from proteins and rRNAs
Random sampling error
Large for small samples and small for large samples
Steps of transformation
Large fragment of DNA binds to surface of cell. Endonuclease enzyme outside the cell cuts up the DNA. One strand of the DNA is degraded, and the other enters the cell. DNA must be incorporated into the chromosome to be stably inherited, results in heteroduplex DNA. Then repaired by DNA repair enzymes. Sometimes transforming recipient to the new genotype
DNA replication is more complicated in eukaryotes because
Large linear chromosomes, tight packaging within nucleosomes, more complicated cell cycle regulation
Lysogeny
Latency in bacteriophage
DNA polymerase III synthesizes the DNA using the RNA primers on both
Leading and lagging strands
Aneurploidy commonly causes an abnormal phenotype
Leads to imbalance in the amount of gene products. 3 copies can lead to 150% production of the hundreds or even thousands of gene products from a particular chromosome
Gene regulation is important for cellular processes such as
Metabolism, response to environmental stress, cell division
Splice junctions in eukaryotes have 2 bases in mRNA that's left behind and 2 bases out
Mutation in intron stops RNA being sliced properly and they get into cytoplasm and creates different protein
lacI-
Mutation in lacI gene. Resulted in the constitutive expression of the lac operon even in the ebsence of lactose
Trinucleotide repeat expansion
Mutation that results in expansion of the number of trinucleotide repeats
Transcriptional repressors inhibit mediator
Prevent switch to elongation stage, preventing transcription
Methylation can repress transcription by
Preventing transcription factors from binding to the DNA
An advantage of CRISPR-Cas is targeting genetic changes
Previous methods usually involve random changes and lots of screening, insertion of new genes in random places
Four levels of structue in proteins
Primary, secondary, tertiary, quaternary
What is needed to make new strands of DNA at the replication fork
Primase, DNA polymerase, and DNA ligase
Annealing in PCR
Primers bind to DNA
MutH can distinguish between the parental strand and the daughter strand
Prior to replication, both strands are methylated. Immediately after replication, the parental strand is methylated but the daughter strand is not
Probe in western blot
Probe is a primary and secondary antibody. Probe is specific to a fragment on the membrane, then protein with the same sequence is there
Lethal allele
One with the potential to cause death. Typically the result of mutations in essential genes and are usually inherited in a recessive manner
A testcross is expected to yield a max of
Only 50% recombinant offsping. Same as if genes were on different chromosomes
Conditional lethal alleles
Only lethal under certain environments
High stringency
Only nearly identical sequences hybridize
Gene redundancy
Only one gene is required for normal phenotype, but multiple versions present
Negative supercoiling
Opposite direction to the spiral of the helix
Eukaryotes also posses
Organelle genomes
Chloroplasts have maternal inheritance
Organelles are inherited only through the egg cytoplasm. Sperm cells do not transmit chloroplasts
Observations that support the endosymbiosis theory
Organelles have circular chromosome (like bacteria). Organelle genes are more similar to bacterial genes than to those found within the nucleus
Inversion heterozygotes
Organisms with one inverted chromosome and one noninverted homolog
Plasmids and viruses used as vectors contain
Origin of replication, a selectable marker, restriction site(s), gene that functions as a visual marker
Small interfering RNAs (siRNAs)
Originate from exogenous sources (not normally made by cells)
Three types of DNA sequences are required for chromosomal replication and segregation
Origins of replication, centromeres, telomeres
Some viruses have a broad host range
Others can infect only a single species or a single cell type
In the F2, the dominant trait plants
Outnumbered recessive trait plants with a 3:1 ratio
Example of sex limited traits: human sexual dimorphism
Ovaries in females, testes in males
Reverse transcriptase PCR (RT-PCR)
PCR can be used to amplify cDNA and potentially quantify RNA transcripts in living cells
In situ hybridization
Probe tissues with labeled DNA to visualize gene expression. 7 developmental genes visualized by in situ hybridization
Transformation
Process by which a bacterium will take up extracellular DNA released by dead bacteria. Uptake of DNA from the environment
Differentiation
Process by which a cell achieves final form and function
Differentiation in development
Process by which a cell becomes a very specialized and committed type
Crossing over
Process in which homologous chromosomes exchange portions of their chromatids during meiosis
X chromosome inactivation
Process that occurs in female mammals in which one of the X chromosomes is randomly turned off in each cell. Which X is chosen at random in different cells early in development
Polyploid plants having an odd number of chromosome sets are usually sterile
Produce highly aneuploid gametes
Cyclic AMP
Produced from ATP by the enzyme adenylyl cyclase. Binds an activator protein known as the catabolite activator protein
Individuals carrying balanced translocations have a greater risk of
Producing gametes with unbalanced combinations of chromosomes. Depends on the segregation pattern during meiosis I
RNA polymerase has many components, nut the sigma factor is what recognizes
Promoter regions in bacteria
The lac operon regions
Promoter, CAP site, operator, protein coding genes, terminator
Mutations in noncoding sequences
Promoters, splice junctions, 5' 3' UTR
Telomerase contains
Protein and RNA. The RNA is complementary to the DNA sequence of the telomeric repeat, allowing telomerase to bind to the 3' overhang
Virus assembly in viral reproduction
Protein and nucleic acid subunits come together to make infectious particles. Some viruses self assemble, some use proteins to help assembly
Genes that encode polypeptides are
Protein coding genes or structural genes. They are transcribed into messenger RNA
A typical bacterial chromosome contains a few thousand genes
Protein encoding genes, intergenic regions
All viruses have a caspid composed of
Protein subunits called capsomers (can be helical or polyhedral). Some have a viral envelope
RNA has been historically studied for its role in making
Proteins
Torpedo model for eukaryotic termination
RNA cute near polyA signal sequence, exonuclease causes complex disassociation
MicroRNAs (miRNAs)
RNAs that are transcribed from genes and from a hairpin structure
Transcription termination
RNA polymerase stops synthesizing RNA. A terminator is reached that causes RNA polymerase and the RNA transcript to dissociate from the DNA
Histones are needed for the compaction of
Radial loops
Transcription elongation
RNA polymerase synthesizes RNA. RNA polymerasae slides along the DNA in an open complex to synthesize RNA
Mutant allele is due to
Random mutations that occur in DNA or induced by scientists
The selection of which chromosome is inactivated is a
Random process
The larger the sample size, the more closely observed results will match expected outcomes. This is due to
Random sampling error
Cycle threshold Ct
Reached when the accumulation of fluorescence is higher than background
Modern Sanger DNA sequencing
Reactions occur in a single tube with each of the 4 ddNTPs labeled with different fluorescent dye
Oxidative stress
Reactive oxygen species can cause damage to DNA
Inborn error of metabolism
Realtionship between inheritance of the trait and the inheritance of a defective enzyme
Hox transcript antisense intergenic RNA (HOTAIR)
Recently discovered ncRNA that alters chromatin structure
Most random mutations produce
Recessive alleles
Target site primed reverse transcription
Retrotransposon transcribed into RNA with a poly A tail, and target DNA is nicked. RNA binds to the nicked site by AT base pairing. Reverse transcriptase makes a DNA copy of the RNA, Endonuclease makes a second cute nearby. Retrotransposon DNA is ligated into the target site
DNA demethylating agents and histone deacetylase inhibitors
Reverse epigenetic silencing of miRNAs that behave as tumor suppressors
Copying RNA into DNA uses
Reverse transcriptase
Retroelements transpose via an RNA intermediate and movement requires two enzymes
Reverse transcriptase and integrase
3 major epigenetic mechanisms
Reversible modification of DNA by addition/removal of methyl groups. Alteration of chromatin by addition/removal of chemical groups to histone proteins. Regulation of gene expression by small, noncoding RNA molecules
The RNA produced has sequences that regulate its function
Ribosomal binding site and start and stop codons
rRNA involved in protein synthesis
Ribosome components (80% of total cellular RNA)
Translation occurs on the surface of large macromolecular complexes
Ribosomes
Eukaryotic ribosome
Ribosomes in the cytosol
Untranslated RNAs that become part of protein RNA complexes
Ribosomes, signal recognition particles, spliceosomes, RNase P, telomerase
Trans acting factors
Regulatory proteins that bind to cis acting elements. They are located elsewhere in the DNA, often a different chromosomes.
Small effector molecules may modulate
Regulatory transcription factor activity
Nucleosome arrangements around promoters are affected by
Regulatory transcription factors and nucleosome/histone modifications
Receptors for steroid hormones are
Regulatory transcription factors inside cells. Hormone binds to its receptor and complex then acts as a transcription factor
LTR retrotransposons
Related to retrovirus. Move around genomes, but cannot produce viral particles. Contain long termina repeats at both ends. Encode reverse transcriptase and integrase
In lower eukaryotes, genes are
Relatively small and contain primariy sequencing encoding polypeptides. Very few introns
DNA topoisomerase I
Relaxes negative supercoils, breaks one strand and rotates the DNA
Stop codons aren't recognized by tRNAs but by proteins called
Release factors
Depurination
Removal of a purine (G or A). Covalent bond between deoxyribose and a purine base is unstable. Undergoes a reaction with water that releases the base from the sugar
Two different directions a shell and internal organs can twist
Right handed (dextral) more common. Left handed (sinistral)
Small nuclear RNA functional role
RNA processing
Allosteric model for eukaryotic termination
RNA synthesis stops near polyA signal sequence due to transcriptional complex disassociating
Allosteric model
RNA synthesis stops near polyA signal sequence. Proteins lost from transcriptional complex causing it to disassociate
Deamination
Removal of an amino group from the cytosine base turning a C into a U and pairing up with A instead of G. DNA repair enzymes can recognize uracil as an inappropriate base in DNA and remove it
Depurination
Removal of purine resulting in apurinic site. Easily fixed but can be replicated. Most common chemical change
DNA polymerase can not
Remove RNA primer from Okazaki fragments. DNA polymerase I removes the primers and fills in gaps
Photolyase
Repair thymine dimers-splits dimer and resorts DNA
Recombination repair
Repairing double stranded breaks of entire chromosomes
Alkyltransferase in direct repair
Repairs alkylated bases. Transfers methyl or ethyl group from base to a cysteine side chain within the alkyltransferase protein. Permanently inactivates akyltransferase
Alkyltransferase
Repairs alylated bases-transfers methyl/ethyl group from C to self
Large genomes contain a huge number of
Repeat sequences. About 50% repetitive DNA in the human genome
Polytene chromosomes undergo
Repeated rounds of replication without cell division. The doubling produces a bundle of chromosomes that lie together in a parallel fashion
Several human genetic diseases are caused by trinucleotide repeat expansion (TNRE)
Repeats increase from one generation to the next. Include spinal and bulbar muscular atrophy, Huntington, fragile X
Most of the variations in genomes between organisms is due to differences in
Repetitive DNA
ATP dependent chromatin modification is a protein complex that uses ATP to
Reposition nucleosomes, remove nucleosomes, change nucleosome composition
Cap binding proteins
Required for the proper exit of most mRNAs from the nucleus. Recognized by initiation factors that are needed during the early stage of translation. Important in the efficient splicing of introns particularly the intron closest to the 5' end
RNA primers
Required to prime (start) the process of replication
Gene regulation in eukaryotes enables them to
Respond to changing environmental conditions and express sub sets of genes needed at particular times in life and cell cycles
Why we need to regulate gene expression
Response to the environment, metabolism, cell division
Enzymes used to cut DNA are known as
Restriction endonucleases or restriction enzymes
Enzymes used to study DNA
Restriction enzymes, DNA polymerases, DNA ligases
Spontaneous mutations
Result from abnormalities in cellular/biological processes. Ex: errors in DNA replication
Unlike nuclear genes, organellular genes are not inherited from both parents
Results in non mendelian results from reciprocal crosses
Complete nondisjunction
Results in one diploid cell and one without chromosomes. The chromosome-less cell is nonviable
lacI- mutation either
Results in synthesis of an internal activator or eliminates the function of the lac repressor that can diffuse throughout the cell
Disease resistance
Slightly reduced protein function, but altered protein prevents infection (i.e. sickle cell)
O3 operon operator sire for lac repressor
Slightly upstream from the promoter
Flap endonuclease removes
Small RNA flaps generated by DNA polymerase delta
Inducers
Small effector molecule that in some cases may increase transcription
Activator and repressor proteins can be bound and affected by
Small effector molecules
Each snRNP contains
Small nuclear RNA and a set of proteins
snRNA
Small nuclear RNA involved in mRNA processing
snoRNA
Small nucleolar RNA processing of rRNA
Transposition involves integration of
Small segments of DNA into chromosomes. Can occur at many different locations within the genome
Red blood cells of heterozygotes tend to rupture when infected by plasmodium, preventing propagation of the malaria parasite and providing resistance
So HbA HbS individuals are better that HbS HbS and HbA HbA
As soon as an mRNA strand is long enough, a ribosome will attach to its 5' end
So translation begins before transcription ends
SDS page
Sodium dodecyl sulphate polyacrylamide gel electrophoresis. Denatures proteins and coats them with vely charged SDS. Separate based on size alone
Human mitochondrial diseases can arise from mutations that occur in
Somatic cells during aging. Mitochondria are especially susceptible to DNA damage from free radicals
Translesion DNA polymerases
Specialized DNA polymerase that is able to replicate DNA through distorted structures and bulky lesions that halt other DNA polymerases; often makes more errors during DNA synthesis than other DNA polymerases
Mutation rates vary substantially between
Species and even within different strain of the same species
Population level
Species traits are selected based on survival and reproduction
Genome size vary greatly between
Species. Variation doesn't necessarily relate to complexity
The trans acting factors (MADS-Box transcription factors) bind to
Specific cis elements activating and repressing 100s of different genes which in turn leads to the development of the different floral organs
De novo methylation
Specific genes are methylated in gametes from mother or father. The methylation of DNA that was previously unmethylated
Alternative splicing is not random
Specific pattern of splicing is regulated in a given cell
Imprinting involves methylation of
Specific regions of DNA
At the cellular level development has three main events
Specification, determination, differentiation
Start codon in mRNA
Specifies the first amino acid in a polypeptide sequence
To get the chi square
Take the observed minus expected squared over expected then add all those up for each
Self fertilization of autopolyploidy will result in
Tetraploid (4n) offspring
Two common protein complexes that communicate the effects of regulatory transcription factors are
TfIID and mediator
CRISPR has a guide RNA
That allows the Cas9 to cut where the guide RNA has laid it out. Making it very precise
HOTAIR acts as a scaffold
That guides two histone modifying complexes to their target genes for scilencing
Positive regulation: has an activator bound to the activator binding site
That leads to transcription
Osmoregulation
The ability to control the amount of water inside the cell
The progression from the primary to the 3D structure is dictated by
The amino acid sequence withing the polypeptide
Base modifiers cause modified bases to not pair with
The appropriate nucleotides in the daughter strand during DNA replication
Breakpoint
The are of break, and if a gene is within it, then expression is affected (position effect)
For some bacterial genes, the translation of mRNA us regulated by
The binding of proteins
Steroid hormones are secreted into
The bloodstream
Pair rule genes establish
The boundaries of segments, then program the developmental fate of the cells within each segment by controlling expression of segment polarity genes
70% of all miRNAs are expressed in
The brain and many are specific to neurons
A chromosomal rearrangement may affect a gene because
The breakpoint occured within a gene
In detailed genetic maps, the locations of genes are mapped relative to
The centromere
Binding of sigma factor of the holoenzyme to the promoter forms
The closed complex
The anticodon is antiparallel to
The codon
What governs the overall supercoiling of bacterial DNA?
The competing action of the enzymes DNA gyrase and DNA topoisomerase I
DNA replication relies on
The complementarity of DNA strands. The AT/GC rule
Transposase
The enzyme that catalyzes the removal of a transposable element and its reinsertion at another location
Relaxase
The enzyme used to nick the F plasmid, guiding one strand to a DNA pump
Aminoacyl-tRNA synthetases
The enzymes that attach amino acids to tTRNAs. 20 types for each amino acid
Cap binding proteins play roles in
The export of some RNAs to the cytoplasm, early stages of translation, splicing of introns
Termination in translation
The final stage occurs when a stop codon is reached in the mRNA
Intergenic suppressor may be a second protein that takes on the role of
The first
Specification
The first cues confer spatially distinct identity
Nonionzing radiation causes
The formation of cross linked thymine dimers which may cause mutations when that DNA strand is replicated
Attenuation inhibits
The further production of tryptophan
With an even number of crossover events the DNA between the genes is exchanged but
The genes remain on the same chromosome. These are not counted as recombinations because they look like the parents even though crossing over occurred
Genes that control development in drosxophilia act in a temporarily and partially ordered cascade starting with
The genes that establish the anterior-posterior axis of the embryp
Transcription
The genetic information in DNA is copied into a nucleotide sequence of RNA
The maternal effect refers to the fact that the phenotype of the offspring is dependent on
The genotype of the mother
In an inversion, the amount of genetic information stays the same. Hence,
The great majority of inversions have no phenotypic consequences
By combining many different cis regulatory elements to control each gene
The huge array of expression patterns needed to generate complex multi cellular organisms can be achieved
DNA helicase breaks
The hydrogen bonds between the DNA strands
Two regions near the Igf2 gene where DNA methylation occurs
The imprinting control region and the differentially methylated region
Extranuclear inheritance
The inheritance of genetic material that is not found within the nucleus (generally inherited from the mother). Mitochondria and chloroplasts
Initiating translation in bacteria
The initiator tRNA recognizes the start codon in mRNA.
A third level of compaction after nucleosomes and fiber involves
The interaction between the fibers and the nuclear matrix
Mediator proteins mediates
The interactions between transcription factors and RNA polymerase
Nucleotide bases (ATCG) are in
The interior. The bases are stacked
A mutation in a trans acting factor is complemented by
The introduction of a second gene with normal function
Group I and II differ in the way that
The intron is removed and the exons reconnected
Repressor from the F factor can diffuse and turn off
The lac operon on the bacterial chromosome
C-value paradox
The lack of correlation between genome size and organism complexity
In each cycle of elongation a peptide if formed between
The last amino acid in the chain and the amino acid being added
Simple mendellian inheritance describes inheritance patterns that obey
The law of segregation and the law of independent assortment
Origin of transfer
The location on an F factor or within the chromosome of an Hfr strain that is the initiation site for the transfer of DNA from one bacterium to another during conjugation
Example of haplodiploid in honey bees
The male is produced from unfertilized eggs that are haploid (one set of 16 chromosomes) and the females grow from fertilized eggs that are diploid (two chromosome sets, 32 total). So only the female arises through sexual reproduction
Genomic imprintin
The maternal Igf2 ellel is silences but the paternal allele is active
Sex determination
The mechanism by which an individual develops into a female or a male
Dosage compensation
The mechanism that keeps levels of expression of X chromosome genes i n balance with those of autosomal genes for both sexes
When miR-200 is expressed at normal levels
The miRNAs inhibit EMT (E-cadherin remains high) so tumors can't metastasis as easily
In linked, the parental phenotypes are observed more than expected in the F2 and
The mixed phenotype is observed less than expected
When a bacteriophage infects a cell it can cause the host DNA to become frangmented
The pieces of the host chromosome can get packaged with the bacteriophage protein
Chromatin remodeling complexes lead to changes in
The position and composition of nucleosomes
Germ cells form at
The posterior pole of the embryo and nuclei in other regions form somatic cells
Capping occurs as
The pre mRNA is being synthesized by RNA pol II. Usually when transcripts is only 20 to 25 bases long
Secondary structure of a protein
The primary structure of a protein folds to form regular, repeating shapes known as secondary structures
DNA helicase and primase are physically boudn to each other to from a complex called
The primosome. Leads to the way at the replication fork
Product rule
The probability that two or more independent events will occur is equal to the product of their respective probabilities
The non mendelian inheritance pattern of maternal effect genes can be explained by
The process of oogenesis
Some transcriptional activators recruit chromatin remodeling enzymes and histone modifying enzymes to
The promoter
Recessive mutant alleles typically produce less functional protein because
The protein is defective or they produce lower levels of the functional protein
Mendels law of independent assortment can be explained by
The random alignment of homologous chromosomes during meiosis
With X-0 sex determination even with XY male, what determines the sex?
The ratio of X chromosomes to autosomes
Since a cell may have different types of mitochondria, whether the cell is affected depends on
The ratio of mutant to normal mitochondria
Frameshift mutations shift
The reading frame to a different sequence downstream from the mutation (and very often terminates early)
Initiation of replication in bacteria other proteins cause
The region to bedn around the DnaA proteins and separate the AT-rich region
Breakpoint
The region where two chromosome pieces break and rejoin with other chromosome pieces
Maps created by recombination analysis estimate
The relative distances between linked genes. Based on the number of times that a crossover event occurs between genes. Creates a linkage map
Hydrolysis of GTP is essential for
The release of SRP for translation to resume
In expression, a region of the tracrRNA is complementary to
The repeat sequences of the pre-crRNA so they pair up
Nucleosomes
The repeating structural unit within eukaryotic chromatin. Shortens the DNA 7 fold
The leading strand is made in the same direction as
The replication fork
Human cleidocranial dysplasia (CCD)
The result of a mutation in the human CBFA gene, the homolog of runt. Characterized by numerous skeletal defects, including no collar bones
Testcross
The result of breeding a recessive homozygote with an organism of dominant phenotype but unknown genotype. Heterozygote X and homozygote recessive
Since most mutations are deleterious, DNA repair systems are vital to
The survival of all organisms
Wobble base
The third base that is the degenerate base
The size and location of the mosaic region from mitotic nondisjunction depends on
The timing and location of the original abnormality. Most severe example is when abnormality occurs during the first mitotic division after fertilization
A single type of micro RNA inhibits
The translation of several different mRNAs through partial complementarity. Because the matching with the mRNA only has to be about 80% the same to the miRNA
Conditions that favor formation of the 3-4 stem loop rely on
The translation of the trpL mRNA
Simple transposition
The transposable element is removed from the original site and transferred to a new site by a cut and past mechanisms. These are called transposons
Exon shuffling
The variation in the patterns by which RNA may produce diverse sets of exons from a single gene
Quaternary structue of a proteinn is formed when
The various polypeptides associate together to make a functional protein
The organisms that show the greatest variation in genome sizes are
The vascular plants
Leaf variegation on mirabilis jalapa is a result of
The way chloroplasts segregate during mitosis
Bacterial cells have one type of ribosome in
Their cytoplasm
The sequence of DNA in a gene is not always colinear with
Their functional mRNAs
The closer the genes are to one another, the lower the chance of
Them undergoing crossing over
If region 1 does not bind to region 2
Then region 2 can bind to region 3 and region 4 can not bind to region 3
If region 1 binds to region 2
Then region 3 can bind to region 4
The three genes exist as two alleles each
There are then 2^3=8 possible combinations of offspring
Transduction
Transfer DNA between bacteria cells through viruses
Conjugation
Transfer of DNA from one bacterium to another following direct cell to cell contact. Direct transfer between cells
Horizontal gene transfer
Transfer of genes between organisms. May occur within or between species. Many bacterial genes are derived from horizontal gene transfer
Vertical gene transfer
Transfer of genes from mother to daughter cell or from parents to offspring
RNA binding proteins regulate
Translation
tRNAs carry amino acids at the 3' end for
Translation
In bacteria the shine delgarno sequence facilitates ribosome binding
Translation initiation in bacteria
Antisense and double stranded RNA can inhibit
Translation of mRNA
Regulation of gene expression can be
Translational or post-translational
Special polymerases help with translesion synthesis
Translesion polymerases contain an active site with a loose flexible pocket to accommodate the abnormal DNA structure. They have low fidelity
Theory: inheritance patterns of traits can be explained by
Transmission patterns of chromosomes during meiosis and fertilization
Retrotransposition
Transposable element is transcribed into RNA, then reverse transcriptase makes a second copy in DNA. These are called retrotransposons or retroelements
All animal species have evolved ncRNAs as a defense against
Transposable elements
PIWI interacting RNAs silence
Transposable elements in animals
Nonhomologous recombination
Transposable elements insert into DNA that has no sequence homology with the transposon
Must human transposons appear to be inactive, but it is possible for a mobile element to
Transpose from one chromosome to another in gamete-forming cells of the mother, causing a genetic disease
At the molecular level, overdominance is due to
Two alleles that produce slightly different proteins
An individual with a reciprocal translocation usually produces 4 types of gamete
Two are viable and two are nonviable. This is termed semi-sterility
An octamer is composed of
Two copies each of four different histones
For a given character, a pea plant contains
Two discrete hereditary factors, one from each parent. The two factors may be identical or different
Non homologous end joining
Two ends are simply pieced back together
In receprical translocations
Two non-homologous chromosomes exchange genetic material
Gene interactions occur when
Two or more different genes influence the outcome of a single trait
Gene interactions
Two or more different genes influence the outcome of a trait
Linked or linkage
Two or more genes do not independently assort and tend to be transmitted together
Gene families
Two or more genes that are homologous that were derived from the same ancestral gene
Duplications can provide additional genes, forming gene families
Two or more genes that are similar to each other
Paralog
Two or more homologous genes within a single species
Homodimer formation
Two slightly different proteins may have better functionality when bound
Chromosome structure alteration: reciprocal translocations
Two way transfer. Two nonhomologous chromosomes may exchange bits of chromosome and lead to a new karyotype
The nucleosome free region is flanked by
Two well positioned nucleosomes the -1 and +1 nuclesomes. They mark the transcription start sites
Translocation down syndrome
Type of down syndrome caused by rearranged chromosome material. There are 3 copies of chromosome 21, but one is attached to another chromosome instead of being separate
Riboswitches
Type of regulation found in prokayotes and eukaryotes. RNA can exist in two different confirmations. One is active and one is inactive
Explansion of trinucleotide repeats may be within the coding sequence of the gene
Typically CAG (glutamine). Encoded protein contains long tracks of glutamine which causes the proteins to aggregate and is correlated with disease progression
The genome of bacteria
Typically a single circular chromosome
Variations in chromosome structure and number
Typically affect more than one gene, important in evolution, can cause disease, important for new strains of crops
The primary structure of an RNA strand is much like DNA but
U instead of T, and ribose instead of deoxyribose
Because of there being even numbers of crossover events, observed recombinations tend to
Underestimate the actual measure of map distance
Genetic maps are useful in many ways including
Understanding genome of a species, cloning genes, inferring evolutionary relationships, understanding human disease, agriculture and selective breeding
Three main types of DNA sequences
Unique or non repetitive, moderately repetitive, highly repetitive
After associating with PAM Cas9
Unwinds adjacent DNA allowing sgRNA to pair with the DNA. Once paired Cas9 cuts the DNA
Deamination of 5-methyl cytosine can occur but does not result in
Uracil. It results in thymine
Ligation
Use ligase to "glue" your gene of interest into the vector
Restriction digest
Use restriction enzymes to cut the plasmid at a specific site
Aneuploidy
Variation in the number of particular chromosomes within a set. Regarded as abnormal. Ex: trisomy (2n+1) and monosomy (2n-1)
Aneuploidy
Variation in the number of particular chromosomes. Leads to imbalance in the amount of gene product
Allelic variation
Variations in specific genes
Allelic variations
Variations in specific genes. Typically single or a few nucleotide changes
Trait or variatn
Version of the character such as tall or dwarf
Methylation in many eukaryotic species, but not all
Vertebrates and plants have abundant DNA methylation
If the genes are close together
Very few recombinant offspring
DNA replication must occur
Very quickly, very accurately, at the appropriate time in the cell cycle
Alternate segregation
Viable and balanced. Chromosomes on opposite sides of translocation cross segregate into same cell
Provirus
Viral DNA that inserts into a host genome
Entry in viral reproduction
Viral genome enters the cell. Either viral genome alone or viral genome with associated proteins. Some viral proteins are immediately produced
Sources of siRNA can be
Viruses that infect a cell, or researchers can make them to study gene function experimentally
Bacteriophage
Viruses that specifically attack bacteria. Composed of genetic material surrounded by a protein coat
Retroviruses
Viruses that use reverse transcriptase to copy RNA into DNA for integration into host cell genome (HIV for example)
SDS page vs western blot for seeing proteins
Western is specific for a protein and SDS is the whole length of protein
Host range differences between viruses
What species a virus can infect and the cells that a virus infects are its host cells
Epistasis
When a gene can mask the phenotypic effects of another gene. A type of gene interaction in which one gene alters the phenotypic effects of another gene that is independently inherited
Overdominance
When a heterozygote is more vigorous than the two homozygotes (aka heterozygote advantage)
There is not one specific promoter sequence but
There is similarity or consensus sequences
Accumulation before fertilization allows development to proceed very quickly after fertilization
Therefore defective alleles in maternal effect genes tend to have a dramatic effect on the phenotype of the individual
E1E2 heterozygotes prodcue both enzymes
Therefore have an advantage under a wider temperature range than either E1E1 or E2E2 homozygotes
Reverse transcriptase lacks a proofreading function
Therefore mutant strains arise frequently. Difficulty for immune system to fight off. Resistant to antiviral drugs
Machine where PCR is done
Thermocycler
Transposable elements are flanked by direct repeats, also called target site duplications
These direct repeat sequences in the same direction on both sides
Genes may have sequences for many different regulatory transcription factors
These may overlap so that the binding of a sequence by one transcription factor may preclude the binding of others. The result in terms of transcription is dependent on what sites are occupied
Maturing animal oocytes are surrounded by maternal cells that provide them with nutrients
These nurse cells are diploid, whereas the oocyte becomes haploid
As with mitochondria, some chloroplast proteins are encoded by genes in the nucleus
These proteins contain chloroplast targeting signals
The most common way to regulate gene expression in prokaryotes (and eukaryotes) is at the level of
Transcription initiation. The rate of RNA synthesis is increased or decreased
Bacterial translation can begin before
Transcription is completed
Combinatorial control
Transcription is controlled by many factors
Binding of proteins to control or regulatory elements affects
Transcription of as associated gene
Synthesis of viral components in viral reproduction
Transcription of viral genes, translation of viral proteins, synthesis of more copies of viral nucleic acid
Order of microRNA biosynthesis
Transcription produces pri-miRNA, folding of pri-miRNA into loop, processed by drosha and exported from nucleus by exportin 5, pre-miRNA or pre-siRNA digested by dicer, RISC RNA complex binnds to mRNA targets, mRNA shuttled to Pbody or degraded
Gene regulation in eukaryotes can occur at different points in the pathway of gene expression such as
Transcription, rate of translation including microRNA control, protein modification, stability of mRNA and protein
Riboswitches can be a form of control for
Transcription, translation, RNA stability, splicing
Regulatory proteins control
Transcription. Rate of RNA synthesis is changed
Histone acetylation makes genes on nucleosomes available for
Transcription. This is reversible and acetyl groups can be removed changing the chromatin from an open to closed conformation
Cell-cell interactions influence
Transcriptional programs and the developmental fate of cells during embryonic development
Prokaryote gene regulation is mainly done in
Transcritpion
Open conformation of chromatin
chromatin is highly extended and transcription can take place
CRISPR-Cas9 requires 2 RNA molecules
crRNA + tracerRNA. Pair and combine with Cas protein to form an effector complex
In expression, the pre-crRNA is cleaved into many small molecules no called
crRNAs
In bacteria the intitiator tRNA is designated tRNA fmet
It carries a modified methionine, N-formylmethionine
The chi square test does not prove the hypothesis is correct
It evaluates whether or not the data and the hypothesis have a good fit
Plants with alloploidy may be more vigorous because
It has a mixture of traits from two species rather than one
Structure of trp operon is similar to the lac operon
It has a regulatory region, operator, promoter
tRNA
transfer RNA; type of RNA that carries amino acids to the ribosome
Structural genes of trp operon
trpA through E encode enzymes involved in trytophan biosynthesis
The first gene in the trp operon is
trpL
Non coding RNAs affect translation and stability of
mRNA
The initiator tRNA recognizes the start codon in
mRNA
Anticodonn region of tRNAs interacts with
mRNA and must be exposed
piRNA sequences are complementary to
mRNA from a transposable element
Poly A is important for
mRNA stability and translation
Researchers had used antisense RNA to inhibit
mRNA translation. But also found that antisense RNA also inhibited mRNA expression
Initiation stage of translation
mRNA, initiator tRNA and ribosomal subunits associate to form an initiation complex
In most cell types, ncRNAs are more abundant than
mRNAs
The genetic material in mitochondria is referred to as
mtDNA
A defense system found in animals involves a type of ncRNA called PIWI-interacting RNA
ncRNA interacts with PIWI proteins and inhibits the movement of transposable elements
Blocker
ncRNA physically prevents a cellular process
Decoy
ncRNA recognizes another ncRNA and sequesters it. Acts as a competitor like transcription factors
Originin of replication bacterial chromosomes
oriC. Origin of replication
Merozygotes
partial diploid bacterial cells containing F plasmid carrying some bacterial genes. Useful for investigating whether components of bacterial operons are cis or trans acting factors
When piRISCs directly inhibit RNAs in cytosol
piRISC binds to TE RNA and an argonaute protein within piRISC cuts it into pieces, inactivating it
piRNAs associate with PIWI proteins to form complexes known as
piRNA induced silencing complexes (piRISCs)
General transcription factors
required for the binding of RNA pol to the core promoter and its progression to the elongation stage
Oogenesis
the production, growth, and maturation of an egg, or ovum
The template strand is read in the
3' to 5' direction. The new strand is made 5' to 3'
In DNA methylation, a methyl group is added to
Cytosine residues
In interphase, each chromosome is located in
A distinct chromosome territory
Mutant allele
A less common version of a gene
A eukaryotic chromosome contains
A long, linear DNA molecule
Binding of the lac repressor to two operator sites requires that the DNA form a loop
A loop in the DNA brings the operator sites closer together. Facilitates the binding of the repressor protein
High chi square values indicate
A low probability that the observed deviations are due to random chance alone
Low chi square values indicate
A low probability that the observed deviations are due to random chance alone
Coiling of the shell is controlled by
A maternal effect gene. Phenotypes controlled by the genotype of the mother
Supercoiling in bacteria is controlled primarily by
DNA gyrase and DNA topoisomerase I
Amino acids acetylated in histones
Lysine
Plants have evolved developmental regulatory systems that
Parallel those of animals
Origins of replication in eukaryotes
Several per chromosome
Spliceosome is composed of
Several subunits known as snRNPs
Xist gene is active on
The condensed chromosome in Barr body
Recriprocal cross
Two crosses that differ in which sex carries the trait
Gene conversion
Two different alleles become identical
RF2 recognizes
UAA and UGA
Hybridization in PCR
Base pairs align of complementary DNA
Telocentric
Centromere at end
Antibodies recognize
Epitotes of an antigen
Germ line transformation
Introducing transgenes
microRNA
Made from endogenous genetic material
The trait that is masked in the F1 is
Recessive
Direct repair
Reverse covalent modifications
Mutations can occur at the chromosomal or
Single gene level
Mutations can alter chromosome
Structure
Syntheitc RNA helped decipher
The genetic code
X linked genes
Those on X only
Amino acids altered in nonsense mutation
Many
GFB can be used as
An expression marker, and to study protein localization
Alternate and adjacent 1 segregations are the likely outcomes when
An individual carries a reciprocal translocation. Occur at about the same frequency
Genetic mosaic
An individual that has somatic regions that are genotypically different from each other
Homozygous
An individual with two identical alleles
Genotype
An individual's specific alleleic compositon
Summary of translational initiation
An initiation factor complex binds to the 5' cap in mRNA. The mRNA binds to a complex consisting of the 40S subunit, tRNA met, and other initiation factors. The entire assembly moves along the mRNA scanning for the right start codon. Once it finds the AUG, the 40S subunit binds to it. The 60S subunit joins to from the 80S initiation complex
Translational repressors
Aprotein that binds to mRNA and inhibits its ability to be translated
Extranuclear inheritance is also known as
Cytoplasmic inheritance
miRNAs are an important form of gene regulation
It can silence certain forms of mRNAs
O1 operon operator site for lac repressor
Slightly downstream from the promoter
Submetacentric
Slightly off center
Heterozygous
An individual with two different alleles
Coding strand
Same sequence as the RNA
Intergenic genes
Short regions between adjacent genes
The lac repressor binds to what site within the lac operon
lacO
F2 generation
offspring of the F1 generation
Specific short sequences are critical for promoter sequences
-35 sequence and -10 sequence aslo known as pribnow box
One map unit is equivalent to
1% recombination
Genes are always represent as the DNA sequence of the conding strand
5' to 3' sense strand
Recessive pattern of inheritance: two affected individuals will have
100% affected offspring
Human mtDNA
13 genes that function in oxidative phosphorylation
Autosomal aneuploidies most compatible with survival are trisomies
13, 18, and 21
A binds with T with
2 hydrogen bonds
Allopolyploidy
2 sets of chromosomes, one from each of 2 different species. More common autopolyploidy.
Linkage
2+ genes that do not independently assort because they are physically associated (on the same chromosome)
Linkage groups in humans
22 autosomal linkage groups, one X chromosome linkage group, and one Y chromosome linkage group
Recessive pattern of inheritance: two unaffected heterozygous individuals will on average have
25% affected offspring. Can skip generations
Segmentation genes
3 classes: gap, pair rule, and segment polarity genes. Divide embryo into a series of stripes or segments. Define number, size and polarity of each segment
Trisomy
3 copies of a chromosome (2n+1)
G binds with C with
3 hydrogen bonds
Codons in mRNA
3 nucleotide seqences within the mRNA that specify particular aminos acids
The RNA modification that is important for mRNA stability
3 polyA tailing and 5' prime cap
UvrA, B, C, and D recognize and remove
A short segment of damaged DNA. DNA polymerase and ligase finish the repair job
Random insertion may place an element near a cellular promoter which will produce
A silencing RNA
Hemizygous
A gene present on the X chromosome that is expressed in males in both the recessive and dominant condition
trpR
A gene that encodes the trp repressor protein
Single guide RNA (sgRNA)
A 20 nt region pairs with target DNA. By altering the 20nts, the effector complex can be targeted to different sequences
Heteroduplex
A DNA double helix composed of single strands from two different DNA molecules
Cis effecting or cis acting element
A DNA sequence that must be adjacent to the gene(s) it regulates. DNA sequences that bind regulatory proteins
Homeobox
A DNA sequence within a homeotic gene that regulates development in animals. Encodes a 60 amino acid DNA binding domain
Transposition often occurs around the tme of replication
A TE can transpose ahead of the replication fork and be copied again. One genome will still have one TE, but the other will now have two copies
Maternal effect genes
A gene that, when mutant in the mother, results in a mutant phenotype in the offspring, regardless of the genotype
DNA obeys the AT/GC rule of base pairing but during DNA replication an incorrect base may be added by mistake creating
A base pair mismatch
Mutagens
A chemical or physical agent that interacts with DNA and causes a mutation
An inversion
A chromosomal segment that has been flipped to the opposite orientation
A chromosomal deletion occurs when
A chromosome breaks and a fragment is lost
Secondary structure of tRNAs
A cloverleaf pattern containing 3 stem loop structures, variable regions, an acceptor stem with a 3' single stranded region
DNA library
A collection of thousands of different cloned fragments of DNA
Epistatic interactions often arise because two different proteins participate in
A common cellular function. For example an enzymatic pathway
Several human disease have been shown to involve inherited defects in genes involved in NER
A common characteristic is an increased sensitivity to sunlight
Feedback inhibition
A common mechanism to regulate the activity of metabolic enzymes. The final product in a pathway often can inhibit an enzyme that acts early in the pathway
The size and shape of all animal bodies are controlled by
A common set of genes and developmental mechanisms
Homologous recombination
A donor DNA template can be added (with homologous ends to the break) which will be switched into the chromosome. Can be used to add a desired sequence of DNA
RISC is composed of
A double stranded RNA molecule that is 20-25bp long produced from pre-miRNAs and pre-siRNAs by dicer. One strand will be degraded
Many RNA viruses have either dsRNA genome or exist as
A dsRNA during their life cycle
A single chromosome usually has
A few hundred to several thousand genes
Variation in functional activity in overdominance
A gene E encodes a metabolic enzyme
X linked
A gene carried on the X chromosome. If a male inherits an X-linked recessive trait from his mother, he expresses that trait because the Y from his father has no counteracting gene. Females are more likely to be carriers of X-linked traits but are less likely to express them
Inversion position effect
A gene is repositioned in a way that alters its expression
Development biology looks to answer how
A given cell at a precise position in the embryo switches on or off specific genes at timed stages of development
Punnett square
A grid that enables one to predict the outcome of a simple genetic crosses
Operon
A group of two or more genes under the transcriptional control of a single promoter
Viral envelope
A membrane that cloaks the capsid that in turn encloses a viral genome.
One of the strands of DNA serves as a template whose information is transcribed into
A messenger RNA mRNA
Mapping
A method of determining the location of genes relative to each other on the chromosomes
Blotting
A method of transferring RNA/DNA/Proteins onto a membrane
Karyotype
A micrograph of metaphase chromosomes from a cell arranged in standard fashion
Disease resistance in over dominance
A microorganism infects a cell only if cellular proteins function optimally
X linked inheritance
A pattern of inheritance in which a recessive gene is carried on the X chromosome, so that males are more likely to be affected
Prophage
A phage genome that has been inserted into a specific site on the bacterial chromosome.
Testcross
A phenotypically sominant individual is mated with recessive individual
Nucleotide structure
A phosphate group, a pentose sugar (DNA or RNA), a nitrogenous base (A,G,C,T)
When a flower has male and female structures
A plant can fertilize itself, or can be crossed to another different plant
An operon encode
A polycistronic mRNA that contains the coding sequence for two or more genes
TATA box
A promoter DNA sequence crucial in forming the transcription initiation complex in bacteria
Attenuator sequence
A segment of DNA important in termination of transcription in attenuation
Genetic transfer
A segment of DNA is transferred from one bacterium to another. Useful for mapping genes
An insulator
A segment of DNA that functions as a boundary between two genes/DNA regions
Gene
A segment of DNA used to make a functional product
Intron
A segment of a DNA or RNA molecule which does not code for proteins and interrupts the sequence of genes
A chromosomal translocation occurs when
A segment of one chromosome becomes attached to another
Operator
A sequence of bases that provides a binding site for a repressor protein
Promoter
A sequence of bases that signals the beginning of transcription
A CRISPR array consists of
A series of palindromic sequences separated by spacers derived by foreign DNA molecules (from viruses or plasmids)
Conjugation is mediated by
A sex pilus
Notch signaling pathway
A short range system that works through direct cell-cell contact to control the developmental fate of interacting cells
Mitochondria codons
AUA=methionine, UGA=tryptophan
When PIWI protein is mutated in flies
A transposable element called the P element proliferates and testes are smaller
Lysogenic cycle
A viral reproductive cycle in which the viral DNA is added to the host cell's DNA and is copied along with the host cell's DNA
The start codon for eukaryotic translation is
AUG. Usually the first QUG after the 5' cap
Spontaneous mutations can be caused by
Aberrant recombination, aberrant segregation, errors in DNA replication, transposable elements, depurination, deamination, tautomeric shifts, toxic metabolic products
Aberrant segregation
Abnormal chromosomal segregation may cause aneuploidy or polyploidy
Three types of DNA sequences in oriC are functionally significant
AT-rich region, DnaA boxes, GATC methylation sites
What drives strand separation in bacterial replication
ATP for energy
Typically mitochondrial disease affect cells that require high levels of
ATP for proper functioning
One aspect of mitochondrial diseases is that they have different symptoms but all show deficiencies in
ATP synthesis
Some chemical mutagens disrupt appropriate pairing between nucleotides by
Alkylating bases within the DNA
The different globin gene paralogs
All bind oxygen, myoglobin stores oxygen in muscle cells, different globins in the red blood cells at different developmental stages
Sex chromosome aneuploidies generally have less sever effects explained by X inactivation
All but one X chromosome transcriptionally suppressed
The genes assorted independently
All eight combinations (3 genes, two alleles each) would occur in equal proportions
The genome comprises
All the genetic material that an organism posses
Hox genes are not specific to insects and have been identified in
All vertebrates
Genomic imprinting of the Igf2 gene
Allele from the father is expressed but the mother's is not. Based on patterns of DNA methylation which occurs in two regions near the gene
Sex influenced
Allele is dominant in one sex, but recessive in the other. These genes are on an autosome, not a sex chromosome. Sex is influencing heterozygotes
Allele i is recessive to both IA and IB
Alleles IA and IB are codominant. In cells with both alleles the trait is a combination of both phenotypes
Epistasis
Alleles for one gene masks another (for example, two different proteins combine to provide function)
Variation in function
Alleles may have slight variations in function or in the temperature at which they function
Dominant mutant alleles
Alleles that effect phenotype as just one copy. Less common in natural populations
The lac repressor is inactivated by binding to
Allolactose
Degradative plasmids
Allow bacterium to metabolize an unusual substance
Selectable marker
Allow for isolation of host cells that carry the vector and force them to maintain the vector-usually antibiotic resistance
Transcriptional activators
Allow for switch from initiation to elongation
Fluorescence (emmitance of a specific light frequency)
Allows us to see stuff
Two main types of secondary structures
Alpha helix and beta sheet
One polypeptude can have regions of both
Alpha helix and beta sheet. Other regions may lack secondary structures
Chromosomes are replicated and passed from parent to offspring
Also from cell to cell during development. Chromosomes retain individuality during transmission
Silent mutations
Alter codon but do not change the amino acid encoded
Retroviruses can also move genes in and out of genomes and
Alter host gene expression
5' and 3' untranslated (UTR) region can
Alter stability of RNA and in regulatory element/operator site can get disruption of regulation of gene expression
Missense mutations
Alter the amino acid sequence. Still code for an amino acid, but not the correct amino acid
Transposable elements effects on gene expression and chromosome structure
Altering protein encoding genes, altering or providing new regulatory elements, changing splicing patterns, serving as DNA methylation sites, recombination between transposons can cause chromosomal rearrangements
Remodeling complexes may alter nucleosome structure in several ways
Altering the contact between DNA and histones, altering the path of the DNA around the nucleosome, altering the structure of the nucleosome core itself
Chromatin structure is highly dynamic and it is regulated by
Altering the specific histone proteins present in nucleosomes, modification to histone tails, modifications to the DNA itself (methylation)
Meiotic segregation can occur in one of three ways
Alternate segregation, adjacent 1 segregation, adjacent 2 segregation
One benefit of genes with introns is a phenomenon called
Alternative splicing
Gene regulation via RNA processing and translation
Alternative splicing, RNA stability, RNA interference, translational regulation
Missense mutation
Alters the amino acid sequence
tRNA take the anticodon to produce the
Amino acid
Aminoacyl-tRNA synthetases catalyze a two step reaction involving three different molecules
Amino acid, tRNA, and ATP
tRNA work with the ribosome, read mRNA from 5' to 3', adds amino acids to the polypeptide chain to make
Amino acids
The common stable form of adenine and cytosine is the
Amino form. At a low rate, A and C can interconvert to an imino form
Histone proteins have a globular domain and a flexible charged
Amino terminus or tail
qPCR is used for comparing
Amount of DNA template
Amount of product from qPCR correlates with
Amount of target in sample
Quantitative PCR (qPCR)
Amounts of product produced are measured in real time during the PCR process, not just at the end
PCR basic definition
Amplify the gene of interest
PCR research applications
Amplifying, library screening, genotyping, modifying DNA sequence, differential screening, quantifying gene expression
Retroelements transpose via
An RNA intermediate
Cellular proteins target to a particular location within cells is facilitated by
An RNA protein complex called signal recognition particle (SRP)
Anitsense RNA
An RNA strand complementary to mRNA
RNAs containing 3 nucleotides could stimulate ribosomes to bind a tRNA
An RNA triplet acts like a codon. Different triplets could cause binding of different tRNAs and their associated amino acids
Base excision repair and nucleotide excision repair
An abnormal base is recognized and removed from the DNA and a segment of DNA in this region is excised, and then complementary DNA strand is used as a template to synthesize a normal DNA strand
The lac operon is also regulated by
An active protein. It can be transcriptionally regulated by catabolite repression
Adaptor hypothesis
An adaptor molecule connects the codon and the amino acid
Incomplete penetrance
An allele does not always penetrate into the phenotype of the individual. Not all individuals with a mutant genotype show the mutant phenotype
Sex influenced traits
An allele is dominant in one sex but recessive in the other. Thus sex influence is associated with heterozygotes
Mutations can be detrimental if they result in
An allele that functions more poorly than the original
Lethal allele
An allele that has the potential to cause death. Generally inherited in a recessive manner. Typically mutation in an essential gene
IPTG
An allolactose analogue that can induce the lacZ gene
Missense mutations change a codon and result in
An altered amino acid within a protein coding portion of a gene. Ex: GAC to GAG
Difference between an endonuclease and an exonuclease
An endonuclease can cleave within a strand, whereas an exonuclease digests a strand, one nucleotide at a time
Reverse transcriptase
An enzyme encoded by some certain viruses (retroviruses) that uses RNA as a template for DNA synthesis
Direct repair
An enzyme recognizes an incorrect alteration in DNA structure and directly converts in back to a correct structure
Allele E2 encodes
An enzyme that functions better at higher temperatures
Nonrecombinant
An offspring whose combination of traits has not changed from the parental generation
Example of paralogs: globin genes
Ancestral globin gene has been duplicated and altered. 14 paralogs on three different chromosomes
Variation in chromosome number (of individual chromosomes or sets)
Aneuploidy (individual) eploidy (sets)
Chromosome numbers can vary in two main way
Aneuploidy and euploidy
MADS box proteins
Another DNA binding domain
Maternal effect gene types
Anterior, posterior, terminal group
Segment polarity genes divide each segment into
Anterior-posterior axes, which are then given identity by hox genes
Vectors usually have a gene that confers
Antibiotic resistance. Frequently ampicillin resistance for plasmid vectors
Non coding RNA
Any RNA that doesn't encode a polypeptide. Used in DNA replication, gene regulation, transcription/translation, genome defense
Genetic mapping
Any method used to determine the linear order and relative distance between genes that are linked
An antigen refers to
Any molecule that is recognized by an antibody
Gene regulation can occur at
Any of the points on the pathway to gene expression
Somatic cells
Any other cell that doesn't give rise to gametes. Mutations can be passed on to future generations
The lagging strand is made in short bits in the direction
Away from the replication fork
Chemical mutagen
Base modifiers, intercalating agents, base analogs
Induced mutations chemical mutagens
Base modifiers, intercalating agents, base analogs
DNA protein complex for chromosome compaction
Chromatin
Chemical mutagens come in three main types
Base modifiers, intercalating ages, base analogs
Many factors contribute to the tertiary structure of RNA
Base pairing and base stacking within the RNA, interaction with ions, small molecules and proteins
Competent cells
Bacteria able to take up DNA. Carry genes that encode proteins called competence factors
Nucleoside
Base+sugar
Nucleotide
Base+sugar+phosphate
Restriction enzymes are produced naturally by
Bacteria to protect against foreign DNA (bacteriophages)
ncRNAs preform an array of cellular functions in
Bacteria, archaea, and eukaryotes
CRISPR RNAs are encoded by DNA sequences found in
Bacterial and archael genomes
One origin of replication required to initiate DNA replication in
Bacterial chromosomes
Release in viral reproduction
Bacteriophage cause cell to rupture-lysis. Some eukaryotic viruses bud from cell. Results in an envelope of cellular membrane. Membrane may also have viral proteins
The CRISPR-Cas system provides bacteria with defense against
Bacteriophages
Reciprocal translocations lead to rearrangement of genetic material, not a change in total amount. Thus they are called
Balanced translocations
The inactive X chromosome in a human female somatic cell is called a
Barr body
Ionizing radiation can cause
Base deletions, nick in DNA strands, cross linking, oxidized bases, and chromosomal breaks
DNA polymerases have 3' to 5' proofreading ability that can detect
Base mismatches and fix them. If proofreading fails, the mismatch repair system steps in
By varying annealing conditions sequences with more or less identity can
Be detected
Base analogs
Become incorporated into daughter strand during replication
Some euploidy variations are naturally occurring. Ex: bees
Bees are haplodiploid. Females are diploid and males are monoploid (contain a single set of chromosomes)
Behavioral sex determination
Behavioral interactions can determine sex
Primordial myoglobin
Better at binding and storing oxygen in muscle
Pimordial hemoglobin
Better at binding and transporting oxygen via red blood cells
Many response elements are orientation independent
Bidirectional. Function in the forward or reverse orientation
Inducers function in two ways
Bind activators and cause them to bind to DNA. Bind repressors and prevent them from binding DNA
Inducers function two ways to promote transcription
Bind activators and cause them to bind to DNA. Bind repressors and prevent them from binding to DNA
Corepressors
Bind repressors and cause them to bind to DNA
Initiation relies on the ability of RNA polymerase to
Bind to DNA
Small effector molecules
Bind to activators and repressors. Called inducers, corepressors, or inhibitors
The subunits of spliceosome carry out several functions
Bind to an intron sequence and precisely recognize the intron-exon boundaries. Hold the pre-mRNA in the correct configuration. Catalyze chemical reactions that remove introns and covalently link exons
Three common ways that the function of regulatory transcription factors can be affected
Binding of a small effector molecule, protein-protein interactions, covalent modifications
Translational repressors inhibit translation in two ways
Binding to the shine-dalgarno sequence and/or the start codon (blocks the ribosome from initiating translation). Binding outside the shine-dalgarno/start codon region (stabilize an mRNA secondary structure that prevents initiation)
RF3 doesn't recognize any of the three codons
Binds GTP and helps facilitate termination process
Promoter in lac operon
Binds RNA pol holoenzyme
RNA induced silencing complex (RISC)
Binds pieces, makes them single stranded then uses them to target and break down complementary mRNAs
TFIID general transcription factor
Binds to TATA box. Recruits RNA polymerase
tRNA function
Binds to codons in the mRNA and carries amino acids to the ribosomes to be assembled into a protein.
H1 linker histone
Binds to linker DNA and nucleosomes but not as tightly as the core histones
The lac repressor
Binds to the operator and prevents transcription
Iron regulatory protein (IRP)
Binds to transferrin receptor mRNA and to ferritin mRNA and controls their translation
trp operon is involved in
Biosynthesis of the amino acid trytophan
Repressors sit by the promoter region and
Block transcription
Fetal hemoglobin can cause problems when nitrite pollution irreversibly binds to fetal hemoglobin and causes
Blue baby syndrome
Homeotic selector genes specify
Body parts
A person with IA IB blood type AB
Both alleles are expressed, known as codominance
Different combinations of gene expression specify
Both segment type and order
Smooth and striated muscles produce more tropomysoin mRNA than
Brain cells
DNA double strand breaks are very dangerous
Breakage of chromosomes into pieces caused by ionizing radiation, chemical mutagens and free radicals. Can cause chromosomal rearrangements and deficiencies
Deletion-portion of chromosome is missing. Due to
Breaks in the chromosome that result in loss of fragment
Robertsonian translocation occurs such that
Breaks occur at the extreme ends of two non homologous chromosomes. The small acentric fragments are lost. Larger fragments fuse at centromeric regions to form a single chromosome
DNA helicase
Breaks the H bonds between strands
Need to know the genotype of the parents to
Build a punnett square
X-Gal
Colorless compound that is cleaved by B-galactosidase into a blue dye
ncRNA molecules involved with genome defense
CRISPR RNA, PIWI-interacting RNA
Most widely used system for gene editing
CRISPR-Cas9
DNA amplification occurs in two ways
Cell division and vector replication
Maternal effect genes encode RNA and proteins that play important roles in the early step of embryogenesis
Cell division, cleavage pattern, body axis
Many lethal alles prevent
Cell division. Death at early age
Proteins are the casual participants of
Cell structure and function
When E-cadherin levels are low
Cells can more easily move to new sites in the body
Germ line cells
Cells that are or give rise to gametes. Mutation is heritable
Recombinant cells
Cells that contain new allelic combination
In intergenic suppressor, proteins may act in the same
Cellular pathway
Bacteria often posses allelic differences that affec their
Cellular traits
Paracentric inversion
Centromere is outside inverted region
Pericentric inversion
Centromere is within inverted region
Acrocentric
Centromere more off center
Metacentric
Centromere near the middle
Submetacentric
Centromere slightly off center
Probability of an outcome is the
Chance or likelihood that the outcome will occur
Reverse mutation
Change a mutant alleles back to wild type
Mutation
Change in DNA sequence
Mutation
Change in DNA sequences (bases)
Position effect
Change in expression of a gene associated with a change in the gene's location within the genome
Inversion
Change in the direction of part of the chromosome. Chromosomal segment has been flipped to the opposite orientation. Amount of genetic info does not change
Chromosome structure alteration: inversion
Change in the direction of part of the genetic material along a single chromosome
Forward mutation
Change in wild type genotype to something new
Transversion
Change of a purine to a pyrimidine or vice versa
Transition
Change of purine to purine or pyrimidine to pyrimidine
A reverse mutation or reversion
Changes a mutant allele back to the wild type
Nonsense mutation
Changes codon into a stop codon
Nonsense mutation
Changes codon to stop codon
As cells enter metaphase, the level of compaction
Changes dramatically
Oxidative DNA damage
Changes in DNA structure that are caused by reactive oxygen species (ROS) if they're not removed
Maternal inheritance in
Chloroplast (cpDNA) and mitochondria (mtDNA)
CRISPR
Clustered regularly interspaced short palindromic repeats
TFIID requires
Coactivators
RNA splicing
Coding sequences in DNA called exons are interrupted by intervening sequences or introns. Transcription copies the entire gene product and introns are later removed, exons are connected together or spliced
mRNA involved in protein synthesis
Coding template
A heterozygote has a phenotype where the contribution of both alleles is evident
Codominance
The genetic information is coded within mRNA in groups of three nucleotides known as
Codons
Many but not all species of bacteria can
Cojugate
RNA induced silencing complex (RISC)
Combination of a small interfering RNA (siRNA) molecule or a microRNA (miRNA) molecule and proteins that can cleave mRNA, leading to the degradation of the mRNA, or affecting transcription, or repressing translation of the mRNA
2D electrophoresis
Combine IEF then SDS-page2 for max separation. Can identify protein spots by mass spectrometry
To fit bacterial cells, the chromosomal DNA must be
Compacted 1000 fold. Proteins organize the DNA into loops
Negative supercoiling helps
Compaction of the chromosome and creates tension that may be released by DNA strand separation
The nuclear matrix
Compacts DNA into radial loop domains. Composed of two parts: nuclear lamina and internal nuclear matrix
Synteny
Comparison of gene order within two sets of chromosomes
cDNA
Complementary DNA. DNA produced synthetically by reverse trascribing mRNA
During mRNA-tRNA recognition the anticodon in tRNA binds to a
Complementary codon in mRNA
All RNAs originate as
Complementary copies of one of the two strands of DNA
The template strand is used to make
Complementary copy of RNA
Non coding strand (template)
Complementary sequence
Anti-miRNA oligonucleotides (AMOs)
Complementary to a specific miRNA and base pairs with it. Blocks the ability of miRNA to function and/or cause it to be degraded
Oligonucleotide primers in PCR
Complementary to sequences at the ends of the DNA fragment to be amplified. Synthetic and about 15-20 nucleotides long. Need to know sequence of DNA to be bound by primers
A phenomenon in which two different parents that express the same or similar recessive phenotypes produce offspring with a wild type phenotype
Complementation
Compaction of interphase chromosomes is not
Completely uniform
The piRISCs enter nucleus and bind to RNA molecules being transcribed from TEs then
Complex then direct the methylation of DNA and trimethyaltion of lysine 9 on histone H3. Modifications recruit proteins that convert euchromatin to heterochromatin, preventing transcription
cDNA library
Composed of cDNA inserts. Should represent all of the mRNA in the cell
Some proteins function as homodimers
Composed of two subunits. When two polypeptides encoded by the same gene bind to each other to form a dimer
Inheritance patterns that deviate from Mendels law are seen when there is more than one gene that
Controls a single trait
qPCR
Computer monitors the amount of PCR product being made over the course of the reaction via probes
Trisomy 21
Condition in which an individual has three number 21 chromosomes, resulting in Down syndrome. Improper chromosome nondisjunction
Transfer of genetic material from one bacterium to another can occur by one of three mechanisms
Conjugation, transduction, transformation
Internal nuclear matrix
Connects to lamina, fills the nucleus interior
Locked nucleic acids (LNAs)
Contain a ribose sugar that has an extra bridge connecting the 2' oxygen and 4' carbon
Histone proteins are basic
Contain many postively charged amino acids. Lysine and arginine
Probe in southern blot
Contains the DNA and tag that shows all the parts of DNA that are complementary. Using X-rays or fluorescent
Regulation of gene expression primarily occurs at the transcription level but
Control also occurs at other levels before and after translation
Mechanism of HOTAIR transcriptional repression
Creates loops and brings in PRC2 and LSD1 which demethylates lysine on histones to modify methylation patterns in the chromatin around the genes and reduce expression of the gene in that air
DNA gyrase (topoisomerase II)
Creates negative supercoild using energy from ATP. Can also relax positive supercoils when they occur
Parts of CRISPR cas systems
Crispr gene has a group of clustered, regularly interspaced, short, palindromic repeats
Steps for recombinant analysis
Cross two true breeding strains (different in two traits), testcross F1 with a true breeding homozygous recessive indivdual, collect data on F2 generation, collect the map distance between pairs of genes, construct the map
Strategy for using three factor crosses to map genes
Cross two true-breeding strains that differ with regard to the three genes to get offspring that are heterozygous for all genes, mate the F1 female heteros with the male homos recessive for all three
Single factor or monohybrid crosses
Crossed only two variants of one character at a time
Bacteria reproduces asexually
Crosses are not used in the genetic analysis of bacterial species
Two factor crosses
Crossing individual plants that differ in two characteristics
Genes that are far apart on the same chromosome may assort independently from each other and separate by
Crossing over
Genetic duplications are usually caused by
Crossing over between improperly aligned homologous chromosomes
Likelihood of crossing over depends on the distance between the two genes
Crossing over is more likely to occur between two genes that are far apart
Mitotic recombination
Crossing over that occurs during mitosis and produces a pair of recombinant chromosomes. Rare and may produce a pair of recombinant chromosomes that have a new combination of alleles
Linked genes can still independently assort due to
Crossing over where there is recombination between homologous chromosomes during meiosis
Inversion heterozygotes have a high change of producing abnormal gametes due to
Crossing over-inverted segment in inversion loop=abnormal chromosome
Chrloroplasts originated from
Cyanobacterium
The small effector molecule in catabolite repression
Cyclic AMP (cAMP)
Short interfering RNAs are produced by two molecular machines
DICER and RISC
DNA polymerase I excises the RNA primers and fills in with
DNA
Order of eukaryotic chromosomal compaction
DNA alone, nucleosome, 30nm fiber, radial loop domains, compaction of radial loops, metaphase chromosome
Both mitochondria and chloroplasts contain their own
DNA and are inherited through maternal cytoplasm in most organisms
Epigenetic changes can be inherited, but may not follow mendelian inheritance
DNA and chromosomal modifications can occur during gametogenesis or early development
Chromosomes composed of
DNA and protein. Double helix of DNA interacts with proteins resulting in complex structures in the form of chromosomes
The compaction of linear DNA in eukaryotic chromosomes involves interactions between
DNA and various proteins
Illumina sequencing (break down)
DNA binds to flow cell and there are fluorescent bound bases and add just one base. Terminate. Take a picture, wash terminator and add another base
Staggered ends
DNA cleaved creates short single stranded ends or sticky ends. Ends can only be joined to ends with complementary sequences
Blunt ends
DNA cleaved has no single stranded ends, any blunt end can be joined to any other blunt end
C-value=
DNA content in a genome (in picograms)
Difference betwewen DNA and RNA
DNA doesn't have a hydroxyl group on 2' and RNA does. DNA is missing that O
Acquisition is CRISPR-Cas
DNA entering cell is identified, processed and inserted into CRISPR array as a new spacer
In bacteria RNA primers are removed by
DNA pol I
Topoisomerase II
DNA gyrase. Relaxes supercoiling in front of DNA helicase
Mediym and large RNAs involved in
DNA imprinting, X inactivation, DNA demethylation, gene transcription, generation of other RNA classes
Unlike gene cloning PCR copies
DNA in vitro without vectors or host cells
DNA pol I cannot join the small DNA fragments on lagging strand. It's accomplished by
DNA ligase
Different molecular changes can underline epigenetic phenomena
DNA methylation, chromatin remodeling, covalent histone modification, localization of histone variants, feedback loops
DNA methylation is carried out by
DNA methyltransferase
Gene conversion occurs in one of two ways
DNA mismatch repair or DNA gap repair synthesis
Base excision repair involves a category of enzymes known as
DNA n-glycosylases. These can recognize an abnormal base and cleave the bond between it and the sugar in the DNA. AP endonuclease then make a cut on the 5' side
Virus chromosomes consist of single or double stranded
DNA or RNA
Matrix attachment regions AKA scaffold attachment regions
DNA sequences interspersed in the genome. They anchor to the nuclear matrix, forming radial loops
SMART sequencing
DNA strand and a single polymerase linked to the bottom of the DNA. The cell is loaded with the four nucleotides incorporated with fluorescence. So there is a flash of light every time a base is added (different color for each)
DNA replication summary
DNA strands come apart, each serves as a template for synthesis of new strands
Vector DNA
DNA that can replicate within an organism without integrating into a host chromosome-plasmids and viruses. Serves as the carrier of the DNA segment to be cloned
Nucleosome remodelers have
DNA translocases. they can move along DNA
Mendels law of independent assortment
During gamete formation, the segregation of any pair of hereditary determinants (alleles) is independent of the segregation of other pairs (alleles of other genes). Two different genes randomly assort their alleles during the formation of haploid cells
Alternative splicig allows one gene to
Encode more polypeptides
lacZ
Encodes Beta galactosidase. Cleaves lactose and lactose analogues. Also convers lactose in allolactose (an isomer)
i alleles in ABO blood type
Encodes a defective enzyme that can't add sugars. The carbohydrate tree is short (called H antigen)
Genes not in the nucleus like in extranuclear inheritance become part of the cell by
Endosymbiosis
Activator proteins bind to what type of DNA sequence?
Enhancers
Beneficial mutation
Enhances survival or reproductive success
A beneficial mutation
Enhances the survival or reproductive success. Good for evolution
piRISCS can prevent transposable element movement in two ways
Enter nucleus and bind to RNA molecules being transcribed from TEs or directly inhibit RNAs in cytosol
Random mutation hypothesis
Environmental factors simply select for the survival of individuals with beneficial mutations
To make synthetic RNA they used
Enzyme polynucleotide phosphylase. In the presence of excess ribonucleoside diposhphates (NDPs) it catalyzes covalent linkage of ribonucleotides into RNA
DICER
Enzyme that cleaves and processes double stranded RNA to produce siRNAs or miRNAs that are 2o-25 nucleotids in length
Integrase
Enzyme that mediates integration
DNA methyltransferase
Enzyme which attaches a methyl group to the number 5 position of the cytosine base, forming 5-methylcytosine
DNA polymerases
Enzymes that catalyze formation of the phosphodiester bond between nucleotides. Synthesize the DNA molecule
Restriction enzymes (endonucleases)
Enzymes that cut DNA at a specific sequence
A cross involving a two gene interaction can produce two distinct phenotypes due to
Epistasis
An inheritance pattern in which the alleles of one gene mask the phenotypic effects of the alleles of a different gene
Epistasis
A key aspect of TRNE is that the triplet repeat can form a hairpin (or stem loop) leading to
Errors in DNA replication
Destabilizing elements are found
Especially in mRNAs that have short half lives. Can be found anywhere on the mRNA
Imprinting can be divided into three stages
Establishment of imprint during gametogenesis, maintenance of the imprint during embryogenesis and in the adult somatic cells, erasure and reestablishment of the imprint in the germ cells
RNA splicing is common in
Eukaryotes and occurs occasionally in bacteria
mRNA processing
Eukaryotic mRNA is modified before it leaves the nucleus. Spliced, capped at 5' end. Poly-A addition at 3' end
The twist demonstrates a non mendelian pattern of inheritance
Even though twist is controlled by a nuclear gene
Mutations are the foundation for
Evolutionary change
Mutations can be harmful and as a result organisms have
Evolved ways to repair damaged DNA
Many genes have multiple alleles (three or more)
Ex: ABO blood type genes in humans
Temperature sensitive (ts) lethals
Ex: a developing drosophila larva may be killed at 30C but will survive if grown at 22C
Some cellular proteins must be targeted to a particular location within cells
Ex: extracellular proteins must be targeted to the plasma membrane in bacteria or to the ER to be secreted
Some lethal alleles exert their effect later in life
Ex: huntingtons disease. Progressive degeneration of nervous system, dementia and early death
Environmental conditions may have a great impact on phenotype
Ex: the arctic fox changes coat color from grayish brown in summer to white in winter
The coding strand has the same base sequence as the RNA transcript on the template strand
Except U instead of T
Illegitimate recombination
Exchange of genetic information between non-homologous DNA molecules
Capping is added to the 5' end of the RNA for
Export from nucleus
Regulated gene expression
Expression may be increased or decreased according to the demand for the gene expression. Encoded proteins will be produced only when required
miR-200 miRNAs are associated with a decrease in
Expression of E-cadherin, a membrane protein that adheres adjacent cells together
Phenotypes of X chromosome aneuploidies may be due to
Expression of X linked genes prior to X inactivation and imbalance in expression of pseudoautosomal genes
Fertility plasmids
F factors that allow conjugation
Strains of bacteria that contain the F factor are designated
F+ and those lacking are F-
The F factor carries genes that allow for transfer of DNA from
F+ cell to F- cell
Sex pili are made only by
F+ strains. They act as attachment sites for other bacteria
For all 7 characters studied
F1 generation showed only one of the two parental traits and F2 generation showed a 3:1 ratio of the two parental traits
Competent cell function
Facilitate binding, uptake and subsequent incorporation of the DNA into the bacterial chromosome
Blending hypothesis
Factors that control hereditary traits are malleable. Blend together generation after generation
Down syndrome
Failure of chromosome 21 to segregate properly due to chromosomal nondisjunction, usually in meiosis I in the oocyte
Meiotic nondisjunction
Failure of chromosomes to segregate properly during anaphase of meisosis. Results in mosaic
Ion torrent
Flushes curvet with each base individually. Measures change in pH. The change in pH tells which base is each. Slower but less expensive
Transfer RNAs tRNAs
Fold into basically the same shape as RNA but they have different sequences
A protein that is a repressor for one gene may be an activator
For another protein
Limit to length of fragment that can be amplified
For most commercial enzymes a few kb. Improved enzymes are constantly being developed
Promoter in eukaryotes
For protein encoding genes, the core promoter often consists of a TATA box and a transcriptional start site
Chromatin remodeling
For replication and gene expression, chromatin must relax its compact structure and expose regions of DNA to regulatory DNA binding proteins
During meiosis I, homologous chromosomes synapse with each other
For the translocated chromosome to synapse properly, a translocation cross must form
Short interfering RNAs (siRNAs)
Form dsRNA. Can be exogenous from a virus or from a researcher wanting to study gene function
Moderately repetitive DNA sequence
Found a few hundred to a few thousand times. Includes genes for rRNA and histones, origins of replication, and transposable elements
Z-W sex determination
Found in birds and some fish. Male is Z-Z the homogametic sex and the females is Z-W the heterogametic sex
X-0 sex determination
Found in many insects, such as grasshoppers. Male is X-0 (has just one X chromosomes). Female is XX
Selenocysteine the 21st amino acid
Found in several enzymes of redox reactions. Encoded by UGA (normally a stop)
Pyrrolysine the 22nd amino acid
Found in some methane producing archaea. Encoded by UAG (normally a stop)
Pseudoautosomal genes
Found on both X and Y. Inheritance patterns are similar to autosomal gnes
Unique or non-repetitive DNA sequence
Found once or a few times in the genome, includes structural genes as well as introns and other noncoding DNA
Highly repetitive DNA sequence
Found tens of thousands to millions of times. Each copy is relatively short
Different patterns of expression of a set of genes called homeotic genes (hox)
From wide range of organisms have a common ancestry
Disease resistance: A microorganism infects a cell only if cellular proteins
Function optimally
A second antibody binds to the first antibody
Fused to a enzyme that creates a visible product
Giemsa stain
G bands. Produces characteristic patterns on DNA
Maternal effect
Gene expression in the mother determines traits of offspring. Genotype of father and offspring has not effect. Controlled by nuclear genes
Mutations in noncoding sequences can affect
Gene expression. But will most likely not do anything
Duchenne muscular dystrophy (DMD)
Gene for DMD i s on the X chromosome. Encodes dystrophin protein, needed muscle structure. Dames heat and breathing muscles
Pleiotropic effects occur because
Gene product may affect cell function in multiple ways, gene may be expressed in different cell types, gene may be expressed at different stages of development
A pattern in which the loss of function in a single gene has no phenotypic effect, but the loss of function of two genes has an effect. Functionality of only one of the two genes is necessary for a normal phenotype
Gene redundancy
Highly condensed metaphase chromosomes undergo little
Gene transcription
The ultimate action of a steroid hormone is to affect
Gene transcription
Homolog
General term for genes that share similar sequence
Two types of transcription factors in eukaryotes
General transcription factors and regulatory transcription factors
P elements are also being used to
Generate mutations and to clone mutant genes
Reactive oxygen species (ROS)
Generated by normal metabolism. Used by immune system to kill invading cells
Transcriptional networks regulate development by
Generating patterns of gene expression. Working in a cascade.
Epigenetic inheritance and imprinting
Genes are altered in the offspring (ex methylation)
Genomic pros and cons
Genes in 1:1 ration. Clones have promoters and introns. Huge amount of extra non coding material
Ortholog
Genes in different species that evolved from a common ancestral gene by speciation
Essential genes
Genes required for survival. Absence of the protein product leads to a lethal phenotype
Duplication events can create paralogs
Genes that are similar to one another that are members of a gene family
Segregation analysis is used in conventional plant breeding and used to identify
Genes that control particular traits
Viral and bacterial chromosomes usually only have one
Genome but can have multiple copies
Maternal effect (maternal inheritance)
Genotype of the mother will determine the phenotype of the offspring. Due to accumulation of gene products that the mother provides to her developing eggs
Typically temperature sensitive proteins mis fold at
Higher temperatures, becoming nonfunctional
Geneticists classify animal cells into two types
Germ line cells and somatic cells
Mutations can occur anywhere
Germ line or somatic cells
ABO blood type genes in humans
Glycosyl transferase adds sugars to the carbohydrate tree on the surface of red blood cells. Antibodies can distinguish between cells with different sugars added (between the different antigens)
Chromosomes can only be microscopically visualized at this part of the cell cycle
Going though metaphase, condensed dividing chromosomes
Mitochondria originated from
Gram negative non sulfur purple bacteria. The intracellular bacterial cells evolved to become modern organelles
Looking at pairs of traits for the flies, the more common recombinants (the two traits together)
Greater distance and more crossing over between these genes
Three different splicing mechanisms
Group I intron splicing, group II intron splicing, spliceosome
Retrovirus
Group of RNA viruses which insert a DNA copy of their genome into the host cell in order to replicate. Ex HIV
Kinetochore proteins
Group of proteins that link centromere to spindle apparatus
Exceptions to chloroplasts having maternal inheritance
Gymnosperms have paternal, some angiosperms have biparental
Accessory enzymes
Gyrases, helicases, ligases
The five types of histones
H2A, H2B, H3, H4. Core histones
Five standard histone genes
HI, H2A, H2B, H3, H4
ncRNA molecules involved with chromatin structure and transcription
HOTAIR, COLDAIR, Xist RNA
ncRNAs and changes to chromatin structure
HOX transcript antisense intergenic RNA (HOTAIR)
During gamete formation, the paired factors segregate randomly
Half of the gametes receive one factor and half receive the other
Antagomirs
Have one or more base modification that promotes stronger binding to complementary miRNAs
If a crossover occurs within the inversion loop
Highly abnormal chromosomes are produced
What's important for unwinding the DNA double helix
Helicase, topoisomerase, and single strand binding protein
Some regions of X and Y without genes share homology
Help in pairing X and Y chromosomes during meiosis I
The ability of gyrase to introduce negative supercoils into DNA is crucial for bacteria to survive
Hence this enzyme can be targeted to cure bacterial diseases
Gene mutations
Hertiable changes in gene sequence
Incomplete dominance
Heterozygotes exhibit a phenotype intermediate between the phenotypes of the homozygotes
Incomplete dominance
Heterozygous have an intermediate phenotype
Overdominance
Heterozygous individual has greater reproductive success compared to either homozygous
P elements can insert themselves into or near genes, causing
High rates of mutation
Paralogs
Homologous genes within a single species
Nuclei of most eukaryotic cells contain chromosomes in
Homologous pairs. They are diploid. Gametes are haploid
DNA double strand breaks can be repaired by two systems
Homologous recombination (HRR) and non-homologous end joining (NHEJ)
Repeats in crispr
Homologous to bacteriophage
Steps of action of glucocorticoids
Hormones diffuse through plasma membrane, binds to receptors, a nuclear localization signal is exposed, two receptors dimerize and enter the nucleus, the dimer binds to glucocorticoid response element, this activates trancription
A successful asexual allopolyploid
Horsetails
CpG islands are unmethylated in
Housekeeping genes. Genes that tend to be expressed in most cells
Analysis of developmental mechanisms
How adult body plan is laid down in the embryo, program of gene expression that turns undifferentiated cells into differentiated cells, role of cell cell communication in development
Variable expressivity
How affected an individual may be by a mutation. Ex: a person with an extra toe is said to have low expressivity of polydactyly and a person with several extra is said to have a high expressivity
Whether a trait is dominant or incompletely dominant may depend on
How closely the trait is examined. Mendel concluded that RR and Rr produced round but microscopic examination of round peas revealed that not all round peas are the same
Leader peptide transcript has several trp codons
How fast it is translated depends on how much trp is in the cell. Which hairpins form controls transcription of the rest of the operon
Chromosomes are linkage groups
How strong the linkage is depends largely on how close the genes are on a chromosome
TFIID is a general transcription factor
It binds the TATA box and recruits RNA pol II to the core promoter
Explansion of trinucleotide repeats may be within the noncoding sequence of the gene
Hypothesized to cause abnormal changes in RNA structure. May produce methylated CpG islands to silence the gene
The initiona of translation requires three initiation factors
IF1, IF2, and IF3
Iron response element (IRE)
IRE is found in the 5' UTR in ferritin mRNA. IRE is found in the 3' UTR in transferrin receptor mRNA
Long terminal repeats
Identical sequences of DNA that repeat hundreds or thousands of times found at either end of retrotransposons or proviral DNA formed by reverse transcription of retroviral RNA
Bacterial conjugation methods were sued to introduce different parts of the lac operon mutant into different strains
Identified F factors that carried parts of the lac operon. Bacteria that receive have to copies of the lacI gene one on the chromosome and the other on the F factor
Penetrance is described at the population level
If 60% of heterozygotes carrying a dominant allele exhibit the trait, the trait is 60% penetrant
Western (protein) blotting can determine
If a protein is made in a particular cell type and if a protein is made at a particular stage of development
RNA northern blotting can determine
If a specific gene is transcribed in a particular cell type and if a specific gene is transcribed at a particular stage of development
Genetic mapping is produced by recombination analysis
If the genes are far apart leads to many recombinant offspring. If the genes are close leads to very few recombinant offspring
Oxidative stress
Imbalance between synthesis/destruction of reactive oxygen species
Amino form tautomeric shift
Imino form (gain H) A and C
PolyA tail
Important for mRNA stability, the exit of mRNA from the nucleus, and in the synthesis of polypeptides
Mitotic nondisjunction
Improper sister chromatid separation that leads to trisomic and monosomic daughter cells. Occurs after fertilization. Usually only a subset of cells affected causing mosaicism
Temperature dependent sex determination is found in some reptiles and some fish
In alligators, eggs incubated at 33 degrees grow into males and few degrees they grow into females. The male and female have the same chromosome composition
TEs offer an advantage
In bacteria, may carry antibiotic resistance genes. May cause insertion of exons into the coding regions of other genes, providing new functions
Like chloroplasts, mitochondria are usually, but not always
Inherited from the female parent via egg cells
Linkage is the tendency of genes that are near one another to be
Inherited with one another
In some cases presence a small effector molecule may
Inhibit transcription
Outcomes of RISC binding to mRNA
Inhibit translation without degrading the mRNA. RISC-mRNA complex may remain in a cellular structure called a processing body. Degradation of the mRNA through cleavage by argonaute
miR-200 miRNA act as tumor suppressors by
Inhibiting an event called the epithelial-mesenchymal transition-the initiating step of metastasis
Double stranded RNA is more potent than antisense RNA at
Inhibiting mRNA
DNA replication occurs in three stages
Initiation, elongation, termination
Three stages of transcription
Initiation, elongation, termination
Three phases for X inactivation
Initiation, spreading, maintenance
Frameshift mutation
Insertion/deletion of nucleotides that cause a shift in the reading frame
Genomic imprinting is permanent in the somatic cells of one animal but
It can be altered from generation to generation
Third step of gene cloning
Introduce recombinant vector with chromosomal DNA into host bacteria (transformation if plasmid vector used, stransfection if a viral vector is used)
cDNA lacks
Introns. Useful for expression in prokaryotes
Changes in chromosome structure
Inversions, translocations, duplications, deletions
Transposase recognizes
Inverted repeats at the ends of a transposable element and brings them closer together
Adjacent 2 segregation
Inviable and unbalanced. Adjacent homologous chromosomes segregate into the same cell. Both have duplications and deletions
Adjacent 1 segregation
Inviable and unbalanced. Adjacent non homologous chromosomes segregate into the same cell. Both have duplications/deletions
Frameshift mutations
Involve addition or deletion of nucleotides in multiple of 1 or 2 but not 3 (the size of one codon)
Antisene RNAs, micro RNAs and short interfering RNA functional role
Involved in gene regulation
The tole of snRNPs in the splicing process
Involved in recognizing the intron boundaries, cutting out the intron, and connecting the two adjacent exons together
DNA methylation in eukaryotes
Involves addition of methyl group to cytosine. Occurs most often on cytosine bases after the CpG island
Induced mutations physical mutagens
Ionizing radiation and nonionizing radiation
Physical mutagen
Ionizing radiation and nonionizing radiation
Physical mutagens come in two main types
Ionizing radiation and nonionizing radiation
DNA repair is a multi step process
Irregularity in DNA structure is detected, abnormal DNA is removed, normal DNA is synthesized
During attenuation, transcription begins but
Is terminated before the entire mRNA is terminated
In trinucleotide repeat expansion, the length of a trinucleotide repeat increases above a certain critical size
It becomes prone to frequent expansion
Within the cell the protein will not be found in a linear state
It will adopt a compact 3D structure. This folding can begin during translation
A chromosomal rearrangement may affect a gene that's left intact but
Its expression may be altered because of its new location - called position effect
Restriction sites for
Joining vector DNA to DNA segment to be cloned
Nonhomologous end joining
Joins without template, tends to produce small insertions or deletions, knocks out genes by disrupting reading frames
Promoter location
Just before, or upstream, of where transcription of a gene actually begins
Primers on the leading strand
Just one primer is made
Chromosomal changes in structure or number are generally detected by
Karyotyping: affect more than one gene
Single stranded binding proteins
Keep the two strands separated until after they are copied
Single stranded DNA binding proteins
Keeps strands apart
Single strand binding protein
Keeps the separated strands apart in DNA replication
The common stable form of thymine and guanine is the
Keto form. At a low rate, T and G can interconvert to an enol form
Many lethal alleles prevent cell division
Kill an organism at an early age
Conditional lethal alleles
Kill an organism only under certain environmental conditions
Semi-lethal alleles
Kill some individuals in a population, not all of them. Environmental factors and other genes may help prevent the detrimental effects of semi lethal genes
Genes in the lac operon are involved in
Lactose metabolism
Okazaki fragments
Lagging strand synthesized as many short RNA-DNA molecules
ncRNAs are broadly categorized according to
Length
Factors that can affect mRNA stability include
Length of the polyA tail and destabilizing elements
Euchromatin
Less condense (acetylated)
Euchromatin
Less condensed regions of chromosomes, transcriptionally active, regions where 30nm fiber forms radial loop domains
Non LTR retrotransposons
Less like retrovirus, may encode reverse transcriptase/endonuclease
Small regulatory RNAs (short ncRNAs)
Less than 200 nucleotides
Genetic linkage can be used to make
Linkage maps
Macromolecules
Lipids, carbohydrates, proteins, nucleic acids (DNA and RNA)
PiCDPK1-GFP
Localizes to the plasma membrane and cytosol and acuses loss of growth polarity in pollen tubes. Possesses N-terminal lipid modification sites
Gene location is eukaryotes
Located between the centromeric and telomeric regions along the entire chromosome
Cis acting elements
Located on the same DNA strand. DNA sequences that exert effects only over a particular gene
Inversion breakpoints
Location of breaks leading to inversion occur in a vital gene. Will disrupt gene function
Some AMOs contain chemical modifications that cause them to bind more tightly
Locked nucleic acids and antagomirs
Environmental agents can cause
Long lasting epigenetic changes
In higher eukaryotes genes are
Longer and tend to have many introns
Heterogametic sex
Male that is X-Y. Two kinds of sperm are produced, either X or Y plus 22 autosomes
During the evolution of mitochondria and chloroplasts, most genes have been
Lost or transferred to the nucleus. Gene transfer has been mostly unidirectional from the organelles to the nucleus
Presence of repressor protein does not completely inhibit transcription
Low basal level of transcription. Produces enough Beta galactosidase and permease to sense if lactose is in the environment
Which regions form loops depends on how much trp is in the cell
Low trp: region 2 and 3 form. High trp: region 1 and 2 form, 3 and 4 aslo form and act as a transcriptional terminator
Hypothesis for imprinting
Males want their offspring to have rapid growth and females must balance rapid growth with saving resources for herself and future offspring
Amino acids altered in frameshift mutation
Many
DNA replication licensing
MCM helicase binds, completing a process called
Small interfering RNA
Made from exogenous genetic material. Naturally from viruses. Used by cell to prevent viral infection
MicroRNAs fall under small regulatory RNAs (short ncRNAs)
Majority associated with gene regulation. 20-25 nucleotides
A1A2 heterozygotes
Make A1A1, A2A2, A1A2 homodimers. For some proteins, the A1A2 homodimer may have better functional activity
A1A2 heterozygotes
Make A1A1, A2A2, and A1A3 homodimers. For some proteins, the A1A2 homodimer may be better functional activity
Reverse transcriptase uses RNA as a template to
Make a complementary strand of DNA
Prototrophs
Make all their nutrients from basic components
The goal of DNA replication is to
Make an exact copy of the DNA
A1A1 homozygotes
Make only A1A1 homodimers
A2A2 homozygotes
Make only A2A2 homodimers
In interference phase, cas9 protein function as an endonuclease that
Makes double stranded breaks in the bacteriophage DNA. Phage proliferation is inhibited
Bacteria are usually haploid
Makes it easier to identify loss of function mutations than in Eukaryotas. Recessive mutations are not masked by dominant alleles
Translation RNA
Making polypeptide chains (proteins), composed of amino acids. All from mRNA that came from DNA
Within genes, a linear sequence of deoxyribonucleotides in DNA contains the information for
Making proteins
The sickle cell allele is found at a fairly high frequency in parts of Africa where
Malaria is found
The genetic code is degenerate
Many amino acids specified by more than one codon
Morphological traits such as height, weight, and pigmentation are affected by
Many different genes in combination with environmental factors
Important genes line on the X chromosome
Many of these genes encode proteins that interact with proteins encoded by autosomal genes
If the genes are far apart
Many recombinant offspring
AU rich element (ARE) is found in
Many short lived RNAs
Low levels of miR-200 family of miRNAs have been associated with
Many types of cancer
Three factor crosses can yield information about
Map distance and gene order
Units of distance between genes
Map units or centiMorgans
Linkage maps
Maps of the relative locations, or loci, of genes on a chromosome
Two different sets of genes control embryonic development in drosphila
Maternal effect genes and zygotic genes
Two sets of genes control developmental genetics in animals
Maternal effect genes and zygotic genes
Pigmentation inheritance exhibits a
Maternal inheritance pattern. Depends solely on mother's phenotype because the egg provides the cytoplasm
Nuclei arrange themselves around the periphery of the zygote and are exposed to gradients of
Maternally derived mRNA transcripts and proteins (provide positional information
Single factor cross
Matings look at one character
Two factor cross
Matings look at two characters
Pre mRNA with multiple introns can be spliced different ways generating
Mature mRNAs with different combinations of exons
Sometimes DNA that enters the cell is not homologous to any genes on the chromosome
May be incorporated at a random site on the chromosome this process is termed nonhomologous or illegitimate recombination
Individuals with inversion heterozygotes
May be phenotypically normal but have a high probability of producing abnormal gametes due to crossing over in the inverted segment
Copia elements
May move to different chromosome locations throughout the genome. Ex: variations in eye color and segment formation are due to copia insertions within genes
RNA interference (RNAi)
Mechanism in which double stranded RNA silences mRNA
Mediator function
Mediates interactions between RNA pol II and various regulatory transcription factors
The third component for transcription is a large protein complex
Mediator
Crossing over occurs in
Meiosis I. Exchange of DNA between non sister chromatids of homologous chromosomes results in genetic recombination
Telomeric sequences consist of
Moderately repetitive tandem arrays, 3' overhang that is 12-16 nucleotides long, each species has a variation of the sequence
Genomic imprinting
Modification of a nuclear gene that alters its expression, but is not permanent over the course of many generations. Form of epigenetic inheritance
Small RNAs (snaRNAs, smRNAs, piRNAs) involved in
Modification of target RNAs, synthesis of telomeric DNA, chromatin structure dynamics, transcription modulation, structural role, gametogenesis
Epigenetic inheritance
Modification to a gene that changes gene expression, but is not permanent over the course of generations. May permanently affect the life of an individual. Not a change in the DNA sequence itself
The histone code
Modifications to histone tails. Also called transcription
In addition to the normal A, U, G, C nucleotides, tRNAs commonly contain
Modified nucleotides
A phenomenon in which an allele of one gene modifies the phenotypic outcome of the alleles of a different gene
Modifying genes
Nucleotide excision repair is found in all eukaryotes and prokaryotes
Molecular mechanism best understood in prokaryotes
The relationship between genes and traits spans four level of biological organization
Molecular, cellular, organism, population
Recombinant DNA molecules
Molecules made by joining DNA from two different sources
Low stringency
More dissimilar sequences can hybridize
Polar and charged amino acids are hydrophilic
More likely to be on the surface of a protein
Acrocentric
More off center
Amount of all genes that are protein encoding genes producing mRNA which is translated
More than 90%
The total amount of DNA in eukaryotic species is typically
More than that in bacterial cells
Capping
Most mature mRNAs have 7-methyl guanosine covalently attached at theur 5' end
Monoecious plants
Most plants produce both male and female gametes from the same individual
Sex influenced does not mean sex linked
Most sex influenced traits are autosomal
Each species of organism contains thousands of genes but
Most species have at most a few dozen chromosomes
Human mitochondrial diseases can be transmitted from
Mother to offspring via the egg. Follow a strict maternal inheritance pattern
Paternally imprinted
Mother's allele is expressed
Two common reasons for position effects
Movement to a position near regulatory sequences and movement to a heterochromatic region
The cascade
Multiple cis elemetns regulate each genes as they are bound by positive or negative regulators. This allows for large combinations of potential expression patterns required for complex organisms
Pleiotropic effects
Multiple effects of a single gene on the phenotype of an organism
Operon: a regulatory unit containing
Multiple genes under the control of a single promoter
Primers on the lagging strand
Multiple primers are needed, primase creates primers for both strands
Genetic material variation
Must be capable of change to account for the known phenotypic variation in each species
Genetic material transmission
Must be passed from parent to offspring
Genetic material information
Must encode the information necessary to make an entire organism
Haploinsufficiency (dominant allele)
Mutant is a loss of function allele and one wild type copy is not enough to provide function. Ex: poludactyly in humans
Complementation
Mutant phenotype of parents generation can be returned to WT phenotype in offspring's generation because alleles complement each other
Dominant negative mutations (dominant allele)
Mutant protein acts to antagonize normal protein
Xeroderma pigmentosum
Mutated single strand nucleotide excision repair gene, which prevents repair of thymidine dimers.; Dry skin w/ melanoma and other cancers
Transcriptional repressors
Prevent switch from initiation to elongation. Prevents transcription
Thermostable DNA polymerase in PCR
Necessary because PCR involves heating steps that inactivate most DNA polymerases. Taq polymerase
Like bacteria, chromosomes of mitochondria and chloroplasts are found in
Necleoids
Deleting the 6 N-terminal amino acids to remove the acylation sites
Negates plasma membrane localization and also the phenotype
Nucleic acid charge
Negative charge. Run on a gel from negative to positive
lac operon regulation
Negative control mechanism. Uses lac repressor protein, repressor binds to operator region. When bound, blocks RNApol binding to the promoter. Binding of allolactose, inactivated repressor so that it can not bind to the operator
Transcriptional regulation involves the actions of two main types of regulatory proteins
Negative control-repressors that inhibit transcription and positive control-activators that increase transcription
Lac operon operator
Negative regulation when bound b repressor protein
Histone proteins bind to
Negatively charged phosphates along the DNA backbone via electrostatic interactions and hydrogen bonds
The chromosomal DNA in bacteria is
Negatively supercoiled
Why is an individual with blood type O considered a universal donor?
Neither the A nor B antigens are present on type O red blood cells.
Likely effect on protein function in missense mutation
Neutral or inhibitory
Eukaryotic cells have two types of ribosomes
One type is found in the cytoplasm and the other in organelles: mitochondria and chloroplasts
Negative regulation: a repressor bound to the operator
No transcription
Positive regulation: no activator
No transcription
Autopolyploidy
Non disjunction in meiosis or mitosis results in diploid gametes (failure to separate the chromosome)
Once DNA has been cleaved by CRISPR-Cas9, cells immediately activate DNA repair mechanisms to fix the break by two main pathways
Non homologous end joining and homologous recombination
Characteristics of viruses
Non living particles, medically important-cause many diseases, nucleic acid genomes, both prokaryotic and eukaryotic cells are infected, rely on living cells to replicate
A crossover in meiosis is an exchange of genetic material between
Non sister chromatids of homologous chromosomes
With crossing over
Non sister chromatids of homologous chromosomes exchange DNA segments
Intergenic regions
Non transcribed DNA segments between genes. Play roles in gene regulation, replication, DNA folding, and genetic recombination
Amino acids altered in silent mutation
None
Likely effect on protein function in silent mutation
None
Without crossing over, gametes carry parental combinations of chomosomes
Nonrecombinant cells
Mutation that is usually the most damaging
Nonsense mutations
Pleiotropic effects: cystic fibrosis
Normal allele encodes the cystic fibrosis transmembrane conductance regulator (CFTR). Regulates ionic balance by transporting Cl- ions. Mutant does not transport chloride effectively. Thus defects in CFTR can have multiple effects
DNA pol I and III are involved in
Normal replication
Chromosome structure alteration: simple translocations
One way transfer
The Y chromosomes are what promote the male development
Not XX directly to promote female. XXY can be a male
Integration in viral reproduction
Not all viruses integrate into host chromosome. Once integrated, genome is called prohphage. The stage is called the lysogenic cycle
Observed offspring ratios of linkage is
Not as expected (9:3:3:1 in dihybrid cross)
Disease resistance: Heterozygotes have one altered copy of the gene with slightly reduced protein function
Not enough to cause serious side effects, but enough to prevent infections
Heterozygotes have one altered copy of the gene with slightly reduced protein function
Not enough to cause serious side effects, but enough to prevent infections
F2 generation contains seeds with novel combinations
Not found in the parental generation
If glucose is not present and lactose is not present these genes are
Not transcribed
If glucose is present it is used as the energy source for transcriptions and lacZ, Y, and A are
Not transcribed regardless of the presence of lactose
Smaller fragments migrate at faster rate than large fragments in
Nuclear acid electrophoresis
Genome differences between viruses
Nucleic acids of a virus are the viral genome
Recombination frequency
Number of recombination/total number of offspring x100
Probability is calculated by
Number of times an outcome will occur/total number of possible outcomes
The lac operon has three operator sites for the lac repressor
O1, O2, O3
Globin gene paralogs characteristics correspond to
O2 needs of embryo, fetus, and adult
Homologous recombination repair
Occurs at the double stranded breaks or when DNA damage causes a gap in synthesis during DNA replication. The strands of a normal sister chromatid are used to repair a damaged sister chromatid
A double crossover separates the gene in the middle from the other two genes at either end
Occurs least because it requires two crossover events. Tell us which gene is in the middle
Autoploidy
Occurs when a diploid plant produces diploid gametes due to nondisjunction during meiosis. Results in one diploid cell and one without chromosomes
Phenotypes controlled by imprinted genes have a non mendelian pattern of inheritance
Offspring express either the maternally inherited or the paternally inherited allele but not both (monoallelic expression)
siRNAs don't go through processing events that occur in the nucleus
Pre-siRNA is formed from two RNA molecules that base pair together
Amino acids altered in missense mutation
One
Human individuals that are not 46 (XY) or 46 (XX) still only have
One active X chromosome
Loss of function alleles may have no effect on phenotype
One gene compensates for the loss of another
Pleiotropic effects
One gene has two or more phenotypic effects
When the two factors of a single character are different
One is dominant and its effect can be seen. The other is recessive and is not expressed
In eukaryotes, SRP is composed of
One nc RNA and six different proteins
In bacteria, SRP is composed of
One ncRNA and one protein
Independent assortment
One of Mendel's principles that states that genes for different traits can segregate independently during the formation of gametes
Conditional mutation
One that affects the phenotype only under specific conditions
PIWI interacting RNAs (piRNAs) associate with a class of proteins called
PIWI proteins
Gap genes activate
Pair rule genes that divide emryo into segments
Gap proteins encode other transcription factors that activate
Pair rule genes whose products divide the embryo into smaller regions about two segments wide
In vertebrate there are 4 clusters of hox genes and their order
Parallels the order of body parts in which they are expressed
Homologous genes within a single species are said to be
Paralogs
In normal individuals, trinucleotide sequences are transmitted from
Parent to offspring without mutation
Dispersive model of DNA replication
Parental and daughter DNA are interspersed in both strands following replication
P generation
Parental generation, the first two individuals that mate in a genetic cross
If the offspring of crosses involved linked genes
Parental phenotypes occur most frequently, double crossover phenotypes occur least, single crossover phontypes occur intermediate
Conserved model of DNA replication
Parental strands stay together after DNA replication
Translocation
Part of a chromosome becomes attached to a non homologous chromosome (simple-one way, reciprocal-two way)
Intron RNA is defined by
Particular sequences within the intron and at the into-exon boundaries
Long term maintenance of the change in gene expression
Passed from cell to cell. May be passed from generation to generation
Spacers in modern bacteria are from
Past infections. The spacer is passed to daughter cells
Nonsense mutations result in
Premature termination of translation
Amino acids are bound together by
Peptide bonds in the backbone
Ribosomes contain three discrete sites
Peptidyl site (P site), aminoacyl site (A site), exit site (E site)
Effects of antisense RNA often
Persisted for a very long time in the cell
RNA interference (RNAi)
Phenomenon in which double stranded RNA causes the silencing of mRNA
Unbalanced translocations are associated with
Phenotypic abnormalities or even lethality
Restriction enzymes break
Phosphodiester bonds in the DNA backbone
Main function of chloroplasts
Photosynthesis
Synteny
Physical linkage of genes into the same chromosome
Deletion
Piece of chromosome deleted
Duplications
Piece of chromosome doubled
Inversion
Piece of chromosome flipped
Translocations
Piece of chromosome moved
Recombination between homologous chromosomes in meiosis exchanges
Pieces of the chromosome
In Mirabilis jalapa, leaves can be green white or variegated
Pigmentation is controlled by the chloroplast (the mothers traits)
True breeding lines
Plants that always produce progeny with the same traits with self fertilized (or bred to the same strain)
Benefits of RNA interference
Presents a newly identified form of gene regulation. May offer a defense mechanism against certain viruses. May play a role in silencing certain transposable elements
Episomes
Plasmids that can integrate into the chromosome
RNA can form stem loop structure which may bind to
Pockets on the surface of proteins
No cytoplasm is transferred through
Pollen (male)
Cross fertilization
Pollen and egg are derived from different plants
Self fertilization
Pollen and egg are derived from the same plant
If the polyA tail is too short,
PolyA binding protein can no longer bind. mRNA will rapidly degrade
Isoelectric focusing (IEF) electrophoresis
Polyacrylamide gel with pH gradient. Not denatured protein. Protein separate based on isoelectric point: the pH at which their charge=0
The second strand of cDNA uses
Polymerase I (does the same job in replication
Extension (synthesis) in PCR
Polymerase copies the target sequences
Some proteins are composed of more than one polypeptide
Polypeptide dentores structure and protein denotes function
Lac operon CAP site
Positive regulation site for catabolite activator protein (CAP)
Topoisomerase II alleviates
Positive supercoiling
microRNAs and siRNAs are involved in
Post transcriptional gene silencing and RNA interference
CRISPR-Cas9 uses relatively long recognition sequence (but not 100% specific)
Potentially allows edits anywhere in a genome. Still needs some screening
In eukaryotes, transcription of structural genes, produces a long transcript known as
Pre-mRNA. Requires a splicesosome to remove introns
Western blotting steps
Proteins are extracted from the cell, separated by 1D or 2D PAGE, dissolved in the detergent SDS which denatures proteins and coats them with negative charges. The negatively charged proteins are then separated by polyacrylamide electrophoresis
Initiation of replication in bacteria DnaA
Proteins bind to sequences in oriC (the DnaA box), then additional DnaA proteins bind to the first set
Methylation results in
Proteins binding to the methylated cytosine and inhibiting transcription. A chromatin structure that silences gene expression
Cellular level
Proteins function within the structures of the cell
Quaternary structure of a protein
Proteins made up of two or more polypeptides have a quaternary structure
Antibodies
Proteins that are used in the immune system
Trans acting factors
Proteins that bind to the cis element DNA sequences
Transcription factors
Proteins that influence the ability of RNA polymerase to transcribe a given gene
Methyl-CpG-binding proteins
Proteins which bind methylated sequences
Examples of antigens
Proteins, carbs, nucleic acids, bacteria, viruses, or cells not normally found in the body
Group I and II self splicing can occur in vitro without
Proteins. However, in vivo, proteins known as maturases often enhance the rate of splicing
CRISPR RNAs can combine with Cas proteins to
Provide defense against invasion of specific DNA molecules
First step of gene cloning
Purify designed DNA and vector (plasmid), difest both with a restriction endonuclease
A transition is a change of
Pyrimidine (C, T) to another pyrimidine or a purine (A, G) to another purine
What makes a good model organism
Quick reproduction, large number of organisms, small genome size
Two main classes of drugs inhibit gyrase and other bacterial topoisomerases, but do not inhibit eukaryotic ones
Quinolones and coumarins
Resistance factors
R factors, give resistance to antibiotics
Bacteria have three release factors
RF1, RF2, RF3
DNA serves as the template for the synthesis of
RNA
RNA may be the final product of the gene or
RNA can be translated into a polypeptide
Torpedo model
RNA cut near polyA signal sequence. Polymerase continues until an exonuclease causes complex disassociation
RT PCR
RNA is exposed to reverse transcriptase and made into DNA and that is run through PCR to understand the gene expression
RT-PCR is carried out in the following manner
RNA is made into first strand cDNA. Single-stranded cDNA is used as template DNA in conventional PCR
If we wanted to look at gene expression
RNA isolation, reverse transcription that convert RNA to cDNA. DNA pol synthesizes 2nd cDNA to create the double stranded cDNA
Self splicing does not require enzymes
RNA itself functions as its own ribozyme
Non coding RNAs
RNA made that doesn't encode polypeptide
RNAi (interference)
RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. Transgene silencing and virus resistance
Ribozyme
RNA molecules with a catalytic function. RNA molecules that have the ability to catalyze a reaction
RNA is electrophoresed, transferred to membrane, then hybridized with a DNA probe in
RNA northern blotting
Nuclear DNA is transcribed by three different RNA polymerases
RNA pol I, RNA pol II, RNA pol III
Basal transcription apparatus
RNA pol II+the five GTFs
Formation of the 3-4 stem loop causes
RNA pol to terminate transcription at the end of the trpL gene
Most regulatory transcription factors do not bind directly to
RNA polymerase
3 categories of proteins are required for basal transcription to occur at the promoter of structural genes
RNA polymerase II, 5 different proteins called general transcription facorts, all protein complex called mediator
Transcription initiation
RNA polymerase binds to DNA. The promoter functions as a recognition site for transcription factors which enables RNA polymerase to bind to the promoter
Example of recriprocal cross in duchenne DMD
Reciprocal crosses demonstrate X linkage in dogs and humans. X linked genes behave differently in reciprocal crosses
In expression, tracrRNA-crRNA complex binds cas9 protein through
Recognition site in tracrRNA
Some splicing factors enhance the ability of a spliceosome to
Recognize a splice site
Base excision repair
Recognize abnormal base and cleaves bond
Splicing factors modulate the ability of spliceosomes to
Recognize or choose the splice sites
Genetic maps can be made by
Recombination analysis or molecular approaches
Inheritance patterns that deviate from Mendels law are seen when there is gene
Redundancy
Goodness of fit
Refers to how close observed data are to those predicted from a hypothesis
Gene cloning
Refers to isolating, and then making many copies of a particular sequence of DNA
The genome in eukaryotes
Refers to one complete set of nuclear chromosomes
Development in cellular biology
Refers to the process that cells and organs undergo in order to reach their final form
Possible hairpin structures
Region 1 and 2, region 3 and 4, region 2 and 3
Terminator sequence
Region in the DNA where RNA synthesis stops
Operon allow bacteria to
Regulate a group of genes that encode for proteins involved in a common process
MADS-Box genes
Regulate large processes. Homeodomains that when active transcribe proteins to start cascade
Transcription factors-DNA binding domain allows the HOX protein to the DNA to
Regulate transcription of a given gene
Gene expression can be
Regulated or unregualted
miRNAs play key roles in
Regulating gene expression, especially during development
microRNAs
Regulation of gene expression
Imprinting control regions (ICRs)
Regulatory elements near imprinted genes that contain transcription factor binding sites (cis acting). Methylated either in the oocyte or sperm but not both
For protein encoding genes 3 features are found in most promoters
Regulatory elements, TATA box, transcriptional start site
Example of sex limited traits: bird plumage and features
Roosters have more ornate plumage than hens, and larger comb and wattles
In humans unique or non repetitive DNA sequeces make up
Roughly 41% of the genome
Polytene chromosomes occur mainly in
Salivary glands of drosophila and a few other insects
Replica plating
Same bacterial cells can be transferred to two plates at the same time. Measure number of tonr resistant colonies-cells resistant to T1 bacteriophage
Probe in northern blot
Same steps as southern blot but replace DNA with RNA and replace some reagents.Detection of specific RNA sequence
RNA polymerase holoenzyme binds loosely to the DNA in bacteria
Scans along the DNA until promoter is reached. Sigma factor recognizes the -35 and -10 regions. Sigma factor that contains a helix trun helix motif gives tighter binding to the DNA
Cytogeneticist
Scientist who studies chromosomes under the microscope
Non research applications of PCR
Screening for mutations involved in genetic disorders. Diagnostic detection of bacteria and viruses in humans and pathogens. Advantageous when studying samples from single cells
Intragenic suppressor
Second mutation in the same gene as the first
Intergenic suppressor
Second mutation is in a different gene than the first
Although sterility is generally a detrimental trait it can be agriculturally desirable
Seedless fruit (triploid varieties propagated by cuttings), seedless flowers (triploid varieties keep blooming longer)
Pangenesis
Seeds produced by all parts of body, collected and transmitted to offspring at conception
Chromosome structure alteration: translocation
Segment of one chromosome becomes attached to a non-homologous chromosome
Pair rule genes control transcription of
Segment polarity genes
Positional information laid down by molecular gradients is interpreted by two sets of zygotic (embryonic genes)
Segmentation genes and homeotic selector
HOX genes are conserved across
Segmented eukaryotes
Transposable elements
Segments of DNA that can become integrated into chromosomes
Physiological adaptation hypothesis
Selected conditions promote formation of specific mutations allowing the organism to survive
Mendel carried out two types of crosses
Self fertilization and cross fertilization
Group I and group II introns are removed by
Self splicing
Signaling systems in early embryonic development act both independtly and in coordinated networks to
Send and receive developmental signals that elicit specific transcriptional responses
Flowers are made of 4 concentric whorls
Sepals, petals, stamens, carpels
PFGE gel electrophoresis
Separation based on re orientation time of DNA strands. Can separate up to 2Mb
Regulatory transcription factors recognize
Sequence elements located near the core promoter. These sequences are known as control or regulatory elements
A translational regulatory protein recognizes
Sequences within the mRNA
Recombinant analysis
Series of crosses specifically aimed at identifying the position of different genes based on the principle of recombination
piRNA genes are usually organized into clusters in which a single pre-piRNA transcript contains
Several different piRNA sequences
Selection is critical for two main reasons
Several different types of product come out of a DNA ligation and a very low percentage of E.coli transformed with plasmid in during transformation
The stability of eukaryotic mRNA varies considerably
Several minutes to several days
Anticipation or dynamic mutation
Severity of disease tends to worsen in future generations
Two unusual features of TRNE disorders
Severity of disease tends to worsen in future generations and severity depends on whether it's inherited from the mother or father
Dynamic mutation
Severity of disease worsens in future generations
In many species, sex determination relies on
Sex chromosomes that are different in males and females. Other mechanisms are environmental or behavioral interactions
Traits that occur in only one of the two sexes
Sex limited traits
A punnett square can be used to predict the outcome of mating if a gene is
Sex linked
Sex affects the phenotype of the individual; some alleles are recessive in one sex and dominant in the opposite sex
Sex linked inheritance
Different chromosomes of the same species can be distinguished from each other and can be classified by
Size, centromere position, banding pattern
Phenotypic consequences of duplications tend to be correlated with
Size. Likely to have phenotypic effects for large pieces of chromosome
Molecular events of conjugation
Sex pilus contacts F- cell, shortens, and a conjugation bridge is formed between cells. A protein complex called the relaxosome binds the origin of transfer in the F factor DNA, and cuts one strand of the DNA. The relaxosome separates the strands ofDNA, leaving the protein relaxase bound. DNA/relaxase complex is pumped out of the donor cell. After transfer of one strand of the F factor, relaxase rejoins the ends to form a circle
Binding of mRNA to the 30S subunit is facilitated by a ribosomal-binding site or
Shine-dalgarno sequence. Complementary to a sequence in the 16S rRNA
Attenuation
Short transcript produced that is translated into a short peptide called leader peptide
The repeats in Crispr are interspersed with
Short, unique sequences, which are called spacers
As mRNA ages, its polyA tail is
Shortened by the action of cellular exonucleases
Example of missense mutation
Sickle cell amenia
Examples of heterozygotes with an altered copy of the gene for disease resitance
Sickle cell anemia and malaria, and tay sachs disease: heterozygotes resistant to tuberculosis
Example of over dominance
Sickle cell anemia. Autosomal recessive disorder where abnormal hemoglobin is produced. Two alleles HbA encodes normal hemoglobin (A) and HbS encodes abnormal hemoglobin (S)
Initiation in bacteria
Sigma factor is needed for promoter recognition
Notch encodes a transmembrane signal receptor
Signal is the delta transmembrane protein. Activates transcription to controls specific developmental pathways
Homologous recombination
Similar DNA segments break and rejoin to form new combinations during crossing over in meiosis
Mismatch repair
Similar to excision repair except that the DNA defect is a base pair mismatch in the DNA not an abnormal DNA
Inheritance of phenotypes follow mendels laws
Simple mendelian inheritance
Mutations may occur at the chromosomal or
Single gene level
What keeps the parental strands apart?
Single strand binding proteins
tRNAs contain both
Single stranded and double stranded regions
RNA is usually
Single stranded but can be double stranded
Polyribosomes or polysomes
Single transcripts that multiple ribosomes are translating simultaneously
dd snail mothers produce
Sinistral offspring even if the offspring are Dd
Crossing over between sister chromatids does not produce a new combination of alleles
Sister chromatids are genetically identical
mRNA ribosome binding site
Site for ribosome binding; translation begins near this site in mRNA
DNA regulatory sequences
Site for the binding of regulatory proteins is to influence the rate of transcription
Promoter sequence
Site in the DNA where the enzymes that synthesize RNA will first bind
Regulatory sequence
Sites in the DNA where proteins interact to control transcription
Structural differences between viruses
Size and shape of the capsid (protein coat) and presence or absence of viral envelope
Phenotypic consequences of deletions depends on
Size of deletion and chromosomal material deleted
Chromosomes are classified by
Size, centromere position and banding pattern
If mirabili jalapa plant develops from a zygote with both mutant and wild type chloroplasts
Some cells get all wild type, some get all mutant, and some get a mix
A gene normally in two copies in a diploid cell may be found in 1, 3, or more copies
Some chromosomes are missing the gene, some have extra copies (segmental duplication)
Often, large sections of the coding region are the same, resulting in two alternative versions of a protein that have similar functions
Some exons always used-constitutive exons, some are not-alternative exons
Dosage compensation mechanisms vary for different species
Some have increased expression in heterogametics and some have decreased expression in homogametics
A forward mutation changes the wild type genotype into
Some new variation
Crossing over results in
Some of the gametes carrying new combinations of alleles - genetic recombination (recombinant cells)
Homodimer formation in overdominance
Some proteins function as homodimers-composed of two subunits
Exon skipping
Some splicing factors inhibit the ability of a splicesome to recognize a splice site
Duplications and mutations have created many histone variants
Some variants play specialized roles in chromatin structure and function
siRNAs play a key role in
Some viral infections. Also useful experimental tools
Heterochromatic effect
Something flipped or moved to a region that's caused it to be heterochromatic
Chromosomal DNA fragments
Source of the DNA segment of interest. DNA purified using a variety of biochemical techniques from tissues and cell of interest
Blots that use hybridization
Southern and northern, not western
Specification in development
Spatially distinct differences in cell types (still reversible)
Telomeres
Special DNA repeat sequences at the ends of the DNA with associated proteins
Splice junctions
Spliceosome may not recognize splice site-intron is included when it shouldn't be
Self splicing
Splicing among group I and II introns
Spliceosome mechanism
Splicing in this case requires a multicomponent structure known as the spliceosome
Insertion of P elements into intron can affect
Splicing or cause premature termination of transcription
After transcription, RNA is modified in eukaryotes
Splicing, capping, poly-A addition tail
Tn elements can move from plasmids onto bacterial chromosomes
Spreading multiple drug resistance between different bacterial strains
Poly-A addition tails are added at the 3' end of RNA for
Stability
PolyA binding protein binds to the polyA tail and enhances
Stability
Depending on the restriction enzyme used, DNA can be cleaved in two different ways
Staggered ends or blunt ends
AUG codon
Start codon (all polypeptides start with this)
To measure the norm of reaction
Start with a true breeding strain of animals with the same genotype, and subject them to different environmental conditions
Termination in transcription
Stem loop
Cleaved end that is more efficient for ligation reactions
Sticky ends/staggered ends
Enhancers
Stimulate transcription
The function of genetic material is to
Store information required to produce an organism. The DNA molecule does so through its base sequence
Z, Y, and A are component of the lac operon that are
Structural
Protein encoding genes
Structural genes. Account for the majority of bacterial DNA
Copy number variation
Structural variation where a DNA segment 1000bp or larger has copy number differences in members of a species
ncRNAs can bind to different types of molecules by
Structurally changing like making loops
Model organisms can be used to
Study human embryonic development and associated genetic disorders
Gap genes are activated to
Subdivide embryo intro broad bands
Hybrid dysgenesis
Sudden appearance of numerous mutations, chromosome aberrations, and sterility in the offspring of a cross between a male fly that possesses P elements and a female fly that lacks them
Intragenic suppressor mutation
Suppresses the effect of an earlier mutation within the same gene. Second mutation in the same gene as the first
Competence factors
Surface proteins that allow a bacterium to take up DNA in transformation
Example of behavioral sex determination in clownfish
Switch from male to female. Male and female clownfish have the same chromosome composition
In homeotic mutants, the structure formed by one segment is
Switched to that of a neighboring segment
Transcriptional activators stimulate mediator
Switching from initiation to elongation
The code is degenerate
Synonymous codons specify the same amino acid. (GGU, GGC, GGA, GGG all code for glycine)
Mutations in HOXD13 cause
Synpolydactyly (SPD), characterized by extra fingers and toes and abnormalities in bones of the hands and feet
Bidirectional
Synthesis occurs in both directions in bacterial chromosomes. Two replication forls move in opposite direction from one origin of replication
DNA sequences are necessary for
Synthesis of RNA and cellular proteins, replication of chromosomes, proper segregation of chromosomes, compaction of chromosomes
Nucleotide sequence of the target DNA must be known in order to
Synthesize primers in PCR
Helper T cells
T cells that help the immune system by increasing the activity of killer cells and stimulating the suppressor T cells
Examples of cis acting elements
TATA box, enhancers and silencers
ncRNA that facilitates the binding of telomerase to the telomere and acts as a template for DNA replication
TERC
Selfish DNA hypothesis
TEs exist because they can. Like parasite, they proliferate in hosts as long as they don't overly harm the hosts
CTD phosphorylation breaks the contact between
TFIIB and RNA polymerase II
Some prokaryotes have a system that defends against foreign invaders
The CRISPR-Cas system. Defense against bacteriphages, plasmids, and transposons. ncRNAs play a key role in determining what is being targeted
If sanger sequencing is used to stop at each base
The DNA can be built back together
Primosome is physcially associated with
The DNA polymerase holoenzyme forming the replisome
Coding strand is the same sequence as
The RNA
The pre-piRNA is processed into one or more piRNAs and each piRNA is complementary to
The RNA of a particular transposable element
Most common type of chromosomal rearrangement in humans
The Robertsonian translocation. Majority of chromosome 21 is attached to 14
A 17 base pair open complex is formed when
The TATA box in the -10 region is unwound. A short RNA strand is made within the open complex and the sigma factor is released, marking the end of initiation
Transcriptional start site
The TATA box plus transcritpional start site comprise the core promoter
The X inactivation center contains
The X inactive specific transcript gene
Bacteria lack nuclei so both transcription and transolation occur in
The cytoplasm
If mitotic recombination occurs during an early stage of embryonic development
The daughter cells containing the recombinant chromosomes continue to divide. May result in a patch of tissue with characteristics that are different than the rest of the organism
In mice, runt is expressed in
The development and formation of blood cells, bone, and the genital system
Interactions between sets of genes results in
The development of specific organs
The percentage of recombinant offspring is correlated with
The distance between the two genes
Telomeres solves the problem of
The ends of linear chromosomes becoming shorter after each DNA replication
Inheritance patterns that deviate from Mendels law are seen when phenotype is influenced by
The environment
Explanation for the cause of incomplete penetrance and variable expressivity
The environment may affect the outcome of the trait and there may be modifier genes that affect the phenotype, which differ in different individuals
Thymine dimers are repaired by
The enzyme DNA photolyase, exposure to light, and transfer of an electron to the dimer
How often genes independently assort depends on how far apart they are on the chromosome
The more DNA between two genes, the longer the chromosome, the higher the likelihood that there will be crossing over between genes
Wild type allele
The most prevalent version of a gene in wild populations. Wild type proteins function normally. They promote the reproductive success of the organism
In humans, mitochondria are inherited from
The mother
The bacterial chromosome is found in a region of the cell called
The nucleoid. Not surrounded by a membrane, DNA is in direct contact with the cytoplasm
Translation
The nucleotide sequence in RNA provides the information to produce the amino acid sequence of a polypeptide
Chromosomes in eukaryotes are located in
The nucleus
The chromosomes of a eukaryotic cell are found in
The nucleus
Map distance
The number of recombinant offspring divided by the total number of offspring, multiplied by 100
In haplodiploid sex determination the sex is determined by
The number of sets of chromosomes
Sequence complexity
The number of times a particular base sequence appears in the genome
Simple transposition can increase
The number of transposons in genomes
The number of linkage groups equals
The number of types of chromosomes of the species
DNA ligase covalently links
The okazaki fragments together
Nucleoids may contain many copies of
The one chromosome
Loss of gene function changes interactions between set of genes and
The organs fate
The pre-replication complex includes
The origin recognition complex
Sugar phosphate backbone is on
The outside
Phenotype
The outward appearance of an individual
In mice with the Igf-2, imprinting causes expression of
The paternal allele but not the maternal. Paternal allele is transcribed into RNA
The central dogma of genetics
The path from gene to protein to trait
Histone cody hypothesis
The pattern of histone modification acts much like a language or code in specifying alterations in chromatin structure
Gene redundancy
The phenomenon in which an inactive gene is compensated for by another gene with a similar function
Plants and animals diverged from a common unicellular ancestor after
The rise of eukaryotes and before the rise of multicellular organisms
Intergenic suppressor. Polypeptides may be subunits of
The same multimeric protein
Mendels law of segregation can be explained by
The separation of homologous chromosomes during meisosis
The sequence of codons within mRNA determines
The sequence of amino acids within a polypeptide
Termination occurs when
The short RNA-DNA hybrid of the open complex is forced to seperate and the newly made RNA is released
Tertiary structure of a protein
The short regions of secondary structure in a protein fold into a 3D tertiary structure. This is the final conformation of proteins that are composed of a single polypeptide
Insertion elements
The simplest type of transposable element. Both ends have inverted repeats. Also called trasposase gene
Origin of replication
The site of initiation and point of control for whole process
What determines the sex of the zygote
The sperm
Chromosomes
The structures that contain the genetic material. Complexes of DNA and proteins
Epigenetics
The study of mechanisms that lead to changes in gene expression, can be passed from cell to cell, are reversible, and do not change the DNA sequence. Change in gene expression not based on DNA sequence
Catabolite repression
The suppression of alternative catabolic pathways by a preferred source of carbon and energy
Because ncRNAs are made of nucleic acids
They can be targeted to different places in the genome or into RNAs
When transposon activity is not regulated and kept under control
They can cause chromosomal abnormalities and sterility
Only certain strains of bacteria can act as donor cells in conjugation
They contain a small circular DNA called an F factor (fertility factor)
Transposable elements are complete (autonomous) when
They contain all the information necessary for transposition to occur
How does UV light and other nonionizing radiation damage DNA molecules?
They create thymine dimers between adjacent thymines in the DNA chain
Transposable elements are incomplete (nonautonomous) when
They lack a gene that is necessary for transposition to occur
Advantages of using pea plants for genetics
They're small and easily grown. Each flower has male and female structures. Many different varieties were available with different traits
Heterochromatin
Tightly compacte regions of chromosomes, transcriptionaly inactive, radial loop domains compacted even further
Nonessential genes
Those not required for survival, but nonessential genes can form lethal alleles
Y linked or holandric genes
Those on Y only. Transmitted from fathers to sons
Four values means
Three degrees of freedom
RNA polymerase in eukaryotes
Three types of RNA polymerases; RNA polymerase II transcribes protein encoding genes
Maintenance in X inactivation
Through mitosis and beyond
Nucleotide excision repair can repair many types of DNA damage including
Thymine dimers and chemically modified bases, and missing bases
Determination in development
Time point at which a specific developmental fate is fixed (irreversible)
Determination
Time point when a specific developmental fate becomes fixed
CpG islands tend to be methylated in
Tissue specific genes when they are not expressed
DNA polymerase function
To add to the growing strand, DNA polymerase uses a dNTP (3 phosphate groups attached at the 5' C)
Purpose of genetic mapping
To determine the linear order of linked genes along the same chromosome. Helps identify genes regulating things we don't know about
Why eukaryotes have multiple origins of replication
To ensure that DNA can be replicated in a reasonable time
SNOW DROP
To remember the types of blotting
Ames test used to evaluate mutagenicity
To see if an agent increases the reversion rate. Uses a strain of salmonella that cannot synthesize the amino acid histidine. Has point mutation in a gene involved in histidine synthesis
mtDNA analysis is a main tool in
Tracking human evolution and migrations
Sex limited
Traits occurs in only one of the two sexes resulting in sexual dimorphism. May be autosomal or sex linked
Organism level
Traits seen at the organism level arise from molecular and cellular properties
Expression in CRISPR-Cas
Transcribed into a long precursor RNA. Cleaved by Cas proteins and processed into crRNAs, each having one spacer sequence. crRNA combined with Cas protein to form an effector complex
If glucose is not present and lactose is present these genes are
Transcribed. Lactose induces the transcription of the lacZ, Y, and A genes
RNA polymerase III in eukaryote transcription
Transcribes all genes for tRNAs
RNA polymerase I in eukaryote transcription
Transcribes all of the genes for ribosomal RNAs
RNA pol III
Transcribes all tRNA genes and the 5S rRNA gene
Gene expression occurs in two steps
Transcription and translation
Molecular level
Transcription and translation produce proteins
Genetic regulation in bacteria is exercised predominantly at the level of
Transcription but there are many examples of regulation that occurs at a later stage in gene expression
Closed conformation of chromatin
Transcription does not take place
Gap proteins
Transcription factors that activate specific pair rule genes. Further division of embryo
Transitions are more common than
Transversions
RNA pol I
Trascribes al rRNA genes (except 5S rRNA)
Crossing of the tetraploid to the original diploid plants will result in
Triploid (3n) offspring which are sterile (impaired meiosis)
The chromosomal anomaly that happens in down syndrome is classified as
Trisomy
When trytophan levels are high
Trytophan acts as a corepressor that binds the trp repressor protein. The trytophan trp repressor complex then binds the the operator site to inhibit transcription
Virulence plasmids
Turn the bacterium into a pathogenic strain
Polyploids (three or more sets of chromosomes) are sterile unless the number is divisible by
Two
At the molecular level, over dominance is due to
Two alleles that produce slightly different proteins
Example of conditional mutation: temperature sensitive (ts) mutants
Used by geneticists to study gene function. E. coli with a ts mutant may grow below 38 degrees but not above 40 degrees
Mendels work was novel
Used quantitative analysis. Developed general laws to predict which phenotypes would appear in offspring and ratios of phenotypes in the offspring
Western (protein) blotting
Used to identify a specific protein within a protein mixture (separated by PAGE)
Fluorescent in situ hybridization (FISH)
Used to identify the location (on a chromosome) of a DNA or RNA of interest
Gene cloning produces an enormous amount of a single DNA sequence
Useful for study and further manipulation
Dideoxy (sanger) method
Uses DNA polymerase to copy a strand of DNA. DNA synthesis is terminated at specific nucleotides by adding dideoxyribonucleotides (ddNTPs) to the reaction. These can be added to a growing polynucleotide chain, but no new nucleotides can be added
Nucleic acid electrophoresis
Uses an electric field to separate DNA and/or RNA fragments by size
Genetic knock down studies
Uses the natural RNAi system. Construct DNA sequence complementary to gene of interest that form a hair pin structure. Leads to double stranded RNA, activation of Dicer and RISC systems
Allopolyploidy begins when two species hybridize
Usually results in a sterile hybrid as the haploid sets cannot pair properly at meiosis
Gene mutation
Usually single base point changes that change one nucleotide to another. Not detectable by karyotype bc too small. Deletion or insertion of nucleotides
Attachment in virual reproduction
Usually specific or only a few cells. Proteins on the virus interact with specific molecules at the cell surface
In E. coli, the NER system requires four key proteins
UvrA, UvrBm UvrC, and UvrD. Named because they are involved in ultraviolet light repair of pyrmidine dimers. Also important in repairing chemically damaged DNA
What protein cuts the damaged DNA strand?
UvrC
Histone cenH3
Variant the is found only at the centromere
Euploidy
Variation in the number of complete sets of chromosomes. Changes the ploidy level. Generally nonviable in animals but important for evolution in plants
Euploidy
Variation in the number of complete sets of chromosomes. Occur occasionally in animals but frequently in plants. Ex: triploid (3n) and tetraploid (4n)
Genomic imprinting: expression of a gene depends on
Whether it is inherited from the male or female parent. Several mammalian genes are imprinted
Mismatch repair system uses methylation patterns to identify
Which base was incorrectly paired (if this system is broken, we see cancer)
trpL RNA can form three different hairpin structures
Which form depends on speed of translation of the leader peptide
Gene cloning is used for
Whole genes or parts of genes
RNAi provides a defense against viruses
Widely used by plants to prevent viral infections
A gene with multiple alleles may have two or more
Wild types
Calico cats exhibit
X chromosome inactivation
Examples of epigenetic inheritance
X chromosome inactivation and genomic imprinting
Initiation in X inactivation
X chromosome is selected fro inactivation
A male is hemizygous for
X linked genes. Since there is only one copy
Inheritance of genes that are located on the X chromosome
X linked inheritance
Ionizing radiation
X rays, gamma rays. Deletions, nicks, cross linking
Turner syndrom
X0 no Barr body
How does a steroid hormone exert its effect upon a cell?
binds to an intracellular receptor to form a complex that then acts as a transcription factor
In the presence of glucose, adenylyl cyclase is inhibited
cAMP levels decrease. cAMP is no longer available to bind CAP, transcription rate decreases
cAMP-CAP complex is an example of induciblegenetic regulation under positive ccontrol
cAMP-CAP complex binds to the CAP site near the lac promoter and transcription rate increases
Regulation of the lac operon: negative control of expression
lacI encodes for a repressor protein, repressor binds to operator region, RNA polymerase cannot reach the promoter when the repressor is bound
Gene responsible for producing the protein that converts lactose to allolactose
lacZ
Lac operon protein encoding genes
lacZ, lacY, lacA
rRNA
ribosomal RNA; type of RNA that makes up part of the ribosome in translation
F1 generation
the first generation of offspring obtained from an experimental cross of two organisms
Phage lambda
well-known bacteriophage that has been widely used in genetic studies & is often a vector for DNA libraries