Bio Unit 4 Inheritance
In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?
0
If you crossed a pea plant homozygous dominant for purple flowers with a plant that was homozygous recessive for white flowers, what percentage of the F1 generation would have white flowers?
0%
Place the following events of transcription in order
1. binding of the σ subunit to the promoter of the gene 2. α, α, β, and β' subunits bind to the initiation site in the promoter 3. dissociation of σ from the promoter 4. addition of nucleotides to the 3' end of the growing mRNA strand 5.
Two organisms with genotype AaBbCcDdEE mate. These loci are all independent. What fraction of the offspring will have the same genotype as the parents?
1/16
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of crosses BbTt × BBtt will be expected to have black fur and long tails?
1/2
In the cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC?
1/64
In humans, "unattached" earlobes are dominant over "attached" earlobes. "Widows peak" hairline is dominant over "non-widows peak" hairline. Use E and e for the earlobe phenotype alleles, and W and w for the hairline phenotype alleles. A female and a male, both with genotype EeWw have a child. What is the probability it will have attached earlobes and a widows peak hairline?
3/16
What phenotypic ratio would you expect to see if you self-fertilized a plant that was heterozygous for two traits?
3:1
A pea plant genotype is SsYyTT (phenotype is smooth, yellow and tall) can make how many different gametes?
4
Consider pea plants with the genotypes GgTt and ggtt . These plants can each produce how many type(s) of gametes?
4 for GgTt and 1 for ggtt
If an mRNA sequence contains 15 nucleotides, how many codons does it contain?
5
A human mother is heterozygous for the sex-linked trait of colorblindness has children with a male that is not colorblind. What percentage of her male offspring are likely to be colorblind. Colorblindness is a recessive trait.
50%
If an individual that has the Hh genotype is crossed with an individual with the hh genotype, how many of their offspring will have an hh genotype?
50%
What percent chance of expressing a recessive X-linked disorder will the son of a woman who is a carrier of have?
50%
If an mRNA sequence contains 21 nucleotides, how many codons does it contain?
7
How many unique gametes could be produced by independent assortment during meiosis if an individual had the genotype AaBbCCDdEE?
8
If cells with the genotype SsYyRr undergo meiosis, how many types of gametes will be produced? Assume that the S, Y and R genes are on different chromosomes.
8
If an mRNA sequence contains 28 nucleotides, how many codons does it contain?
9
What genotypic ratio would you expect to see if you self-fertilized a plant that was heterozygous for two traits?
9:3:3:1
A homologous pair of chromosomes have?
A maternal homologue a paternal homologue two copies of every gene located on the chromosomes
What is a codon?
A sequence of the nucleic acids that designates a particular amino acid
During translation, the polypeptide chain continues to be elongation until what happens?
A stop codon is encountered
According to the Central Dogma of biology, the flow of genetic information in a cell is from Term 1 to Term 2 to Term 3
According to the Central Dogma of biology, the flow of genetic information in a cell is from deoxyribose nucleic acids to ribose nucleic acids to amino acids
Which of the following is/are true of alleles?
Alleles can be dominant or recessive Alleles can represent alternative forms of a gene Alleles can be identical or different for any given gene in a somatic cell
Place these events that occur during protein synthesis in the proper sequence
An aminoacyl-tRNA binds to the A site I. 2nd
Binding of [x] to the mRNA can increase its stability while binding of [y] results in its degradation.
Binding of RNA binding proteins to the mRNA can increase its stability while binding of miRNAs results in its degradation.
Binding of a RNA binding protein to the [x] of the mRNA can [y] the stability of the molecule.
Binding of a RNA binding protein to the 3' or 5' UTR of the mRNA can increase or decrease the stability of the molecule.
These regulators are involved in the control of the trp or lac operons in bacteria. Match the correct regulator with its function.
Binds to an activator of lac genes-cAMP Increases binding of RNA polymerase to lac promoter-CAP binds to the trp repressor and converts it to the active form -tryptophan binds to the trp operon and stops trp gene expression -trp repressor binds to the lac operon and switches it off-lacI binds to repressor of lac operon and removes its ability to bind to the lac operon-allolactose
If the offspring of a cross display a 3:1 ratio for a particular trait, what must be true of the parents?
Both of the parents were heterozygous for the trait
Which of the following calculations require that you utilize the addition rule?
Calculate the probability of a child having either sickle-cell anemia or cystic fibrosis if parents are each heterozygous for both
What is true of the degenerate nature of DNA?
Codons that specify the same amino acid typically only differ by one nucleotide Amino acids with chemically similar side chains are encoded by similar codons
x] results from the action of many genes to determine a characteristic while [y] involves traits that are inherited in distinct classes.
Continuous Variation, Discontinuous Variation
Which of the following can play a role in increasing the genetic diversity of an organism?
Crossing over during meiosis Random fertilization of eggs Independent assortment during meiosis
What are chromosomes composed of?
DNA and proteins
Which of these is a difference between RNA and DNA?
DNA contains thymine and RNA contains uracil
Which of the following BEST describes the flow of information in a eukaryotic cell?
DNA to RNA to proteins
Which of the following would be a possible gamete produced by an individual who is heterozygous for two traits, D and E?
De
During transcription the mRNA product is Term 1 to the template strand and is Term 2 to the other DNA strand, called the nontemplate strand.
During transcription the mRNA product is complementary to the template strand and is almost identical to the other DNA strand, called the nontemplate strand
Eukaryotic DNA is wrapped around proteins called Term 1. The proteins and DNA are held together by Term 2
Eukaryotic DNA is wrapped around proteins calledhistones. The proteins and DNA are held together by polar interactions
Eukaryotic mRNAs are usually Term 1, meaning that they specify Term 2.
Eukaryotic mRNAs are usually monogenic, meaning that they specify one protein
A group of genes that are controlled by an operon usually have functions in different metabolic pathways.
False
Every diploid individual has one allele for each trait.
False
If two alleles at a locus differ, the dominant allele determines the organism's appearance for that trait while the recessive allele is not expressed at all.
False
The phosphate groups that make up the backbone of the DNA contribute a positive charge along the outside of each DNA strand.
False
The process of DNA replication is fundamentally different in prokaryotes and eukaryotes.
False
Based on the law of segregation, what are possible genotypes of the gametes of an individual with the genotype Gg?
G g
What molecule is involved in controlling eIF-2 activity during translation?
GTP
Unlike Eukaryotic cells, prokaryotic cells?
Have no nucleus
If two parental organisms have the genotypes Hh and hh, what are the possible genotypes of their offspring?
Hh hh
Highly [x] DNA regions with [y] histones are tightly coiled and transcriptionally inactive.
Highly methylated DNA regions with deacetylated histones are tightly coiled and transcriptionally inactive.
In order to create a translatable mRNA the [x] in the pre-mRNA need to be removed and the [y] need to be linked back together.
In order to create a translatable mRNA the introns in the pre-mRNA need to be removed and the exons need to be linked back together.
In the translation of mRNA to protein, Term 1 correspond to Term 2 in the polypeptide sequence
In the translation of mRNA to protein, 3 nucleotides correspond to 1 amino acid in the polypeptide sequence.
Which of the following statements describes the eukaryotic chromosome?
It consists of a single linear molecule of double-stranded DNA plus proteins
What happens when the corepressor molecule (tryptophan) binds to trp repressor protein?
It converts the repressor to its active form it changes the shape of trp repressor It enables the repressor to bind to the operon a gene
Like DNA, RNA is a linear Term 1 made of four different types of Term 2 subunits linked together by Term 3 bonds
Like DNA, RNA is a linear polymer made of four different types of nucleotide subunits linked together by phosphodiester bonds
If a trait/allele is X-linked this means that?
Males have one copy and females have two
Indicate which of these situations would result in gene expression and which would not.
Methylation of DNA and histones-genes are not expressed histone acetylation-genes are expressed nucleosomes spaced closely together-genes are not expressed nucleosomes that are spaced far apart-genes are expressed
The structure of a protein is related to the sequence of amino acids that make it up, which in turn affects the way that the protein is folded. Match the main type of bond that contributes to the proteins different levels of structure.
Primary- covalent bonds between amino acids Secondary- hydrogen bonds Tertiary- covalent bonds between functional groups
During splicing, which molecular component of the spliceosome catalyzes the excision reaction?
RNA
Why is using RNA as a template for protein synthesis instead of translating proteins directly from the DNA advantageous for cells?
RNA acts as an expendable copy of the genetic material, allowing for DNA to serve as a permanent pristine copy of the genetic information Many mRNA molecules can be transcribed from a single gene, increasing the rate of gene expression
Which is a true statement about ribosomes?
Ribosomal subunits leave the nucleus after being formed in the nucleolus
What is the function of the ribosome in polypeptide synthesis?
Ribosomes hold the mRNA and tRNAs together Ribosomes catalyze the addition of amino acids from tRNAs to the growing polypeptide chain Ribosomes move along the mRNA and eject tRNAs during the translocation process A, B and C
What sequence in the promotor do the transcription factors recognize as a binding site?
TATA
The eukaryotic DNA polymerase I is found in Term 1 and is involved in the production of Term 2
The eukaryotic DNA polymerase I is found in nucleolus and is involved in the production of most rRNAs.
The eukaryotic DNA polymerase II is found in Term 1 and is involved in the production of Term 2
The eukaryotic DNA polymerase II is found in nucleus and is involved in the production of all protein coding pre-mRNAs
The eukaryotic DNA polymerase III is found in Term 1 and is involved in the production of Term 2.
The eukaryotic DNA polymerase III is found in nucleus and is involved in the production of 5S rRNA, tRNAs, and small nuclear RNAs
The process of transcription in Term 1 involves a greater metabolic investment than in Term 2. However, it ensures that the cell transcribes precisely the Term 3 that it needs for protein synthesis
The process of transcription in eukaryotes involves a greater metabolic investment than in prokaryotes. However, it ensures that the cell transcribes precisely the pre-mRNAs that it needs for protein synthesis
What is the difference between the sugar found in DNA and the sugar found in RNA?
The sugar in DNA has one less oxygen then the sugar in RNA
As a ribosome translocates along an mRNA molecule by one codon, which of the following occurs?
The tRNA that was in the A site moves to the P site The tRNA that was in the P site moves to the E site and is released
How are introns thought to play in biological evolution?
Their presence allows exons to be "moved" around creating new proteins with potentially new functions
Cystic fibrosis (CF) is caused by a recessive allele. A child has CF, even though neither of his parents has CF. What can you conclude about the parents?
They are both heterozygous for the CF gene.
In a region of the DNA where the DNA is methylated what you expect to be occuring?
This region would have little or no transcription occurring
What is the major purpose of RNA?
To function in the synthesis of proteins
Because the genetic code is universal, a purified mRNA encoding the keratin protein in humans could be transferred to a plant cell, and the plant would be able to synthesize human keratin.
True
Enhancers and silencers affect the efficiency of transcription but are not necessary for transcription to proceed.
True
Frameshift mutations can occur if mRNA splicing by the spliceosomes is imprecise.
True
Genes that are located on separate non-homologous chromosomes will always sort independently.
True
In order for genes coded for by Eukaryotic DNA to be transcribed sections of the chromosomes must be modified so that the interactions with histones is loosened.
True
Messenger RNA conveys genetic information for building proteins from the nucleus to the ribosomes
True
Multiple ribosomes can translate the same mRNA sequence simultaneously
True
Protein-protein interactions are crucial to the initiation of eukaryotic gene transcription.
True
RNA needs to be processed, shuttled, or translated, before a protein can be synthesized.
True
Ribosomes in eukaryotic cells are identical and can switch from free to bound.
True
The lac repressor determines whether lac operon genes are expressed at all; the state of CAP controls the rate at which lac genes are transcribed.
True
The sequence of nucleotides in the DNA strand that is being transcribed can result in a weakened/instable mRNA sequence that results in termination of transcription.
True
Two different genes may have the same promoter but different distal control elements, enabling differential gene expression.
True
A particular triplet of bases in the template strand of DNA is AGT. What is the corresponding codon for the mRNA that would be transcribe from this template?
UCA
A particular triplet of bases in the coding sequence of DNA is AAA.What is the sequence on the anticodon of the tRNA that binds to the mRNA?
UUU
When using a Punnett square to predict offspring ratios, we assume that?
We assume all of these things
In humans, "unattached" earlobes are dominant over "attached" earlobes. "Widows peak" hairline is dominant over "non-widows peak" hairline. Use E and e for the earlobe phenotype alleles, and W and w for the hairline phenotype alleles. What is the genotype of an individual who is heterozygous for the hairline phenotype and homozygous recessive for earlobes?
Ww ee
What is meant by the genetic code being degenerate?
a given amino acid can be coded for by more than one nucleotide triplet
When translating secretory or membrane proteins, ribosomes are directed to the ER membrane by?
a signal-recognition particle that brings ribosomes to a receptor protein in the ER membrane
Bacterial RNA polymerase has which of the following properites?
a structure that is based on the sequence of its amino acids quaternary structure covalent bonding between its amino acids
For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes?
about 8 million
In order to use the probability method to determine the outcomes of crosses what must be true of the genes?
all of the genes must be assorting independently all the genes must display simple dominant/recessive patterns
Why is it possible for transcription, translation, and mRNA degradation simultaneously in bacterial cells?
all of these processes occur in the same 5' to 3' direction because there are no internal membrane bound compartments in bacterial cells
Regulatory proteins, like trp repressor, are often what type of protein?
allosteric, having an inactive and active form
Altering patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways?
allowing the organism to adjust to changes in environmental conditions
A mutation in which of the following parts of a gene is likely to be most damaging to a cell?
an exon
Which of the following features do all cells share?
an internal solution a cell membrane containing of phospholipids genetic material ribosomes
What is known about the G-C rich boxes and the octomer boxes that are found in the promoter region of some eukaryotic genes?
are often present in more "active" genes in cells they bind cellular factors that increase the efficiency of transcription initiation
Assuming that both parent plants in the diagram below are homozygous, why would all of the f1 generation have yellow phenotypes?
because yellow is dominant over green
What do repressors do?
bind to enhancers and block transcription respond to external stimuli and prevent binding of transcription factors bind to promoter regions and block transcription
Which of the following are involved in post-transcriptional control?
binding of proteins to the 3' and 5' UTR control of RNA splicing
What do transcription factors do?
cause some proteins to find their binding sites facilitate the binding of RNA polymerase
What does phosphorylation of eIF-2 do?
changes the ability of eIF-2 to bind GTP changes the shape of eIF-2
What is result of the lysine in the histone tail being acetylated ?
chromatin structure becomes looser and access to genes changes
Match the term with its correct function/description
cis-acting element: transcription factor binding sites within the promoter that regulate the transcription of a gene adjacent to it trans-acting element: transcription factor binding site found outside the promoter or on another chromosome that influences the transcription of a particular gene enhancer: region outside the promoter that contains distal control elements transcription factors and mediators: molecules that must be bound to promoter before RNA polymerase can bind DNA bending protein: brings the enhancer into contact with mediators & transcription factors
Human Blood types are an example of ?
codominance and multiple alleles
The lac operon and trp operon allow bacterial cells to?
conserve energy and resources
Bacterial are very responsive to changes in their environments. How can bacteria control metabolic pathways in response to changes in nutrient availability?
controlling the expression levels of key genes by post-translational modification of key enzymes to control their activity
A lack of which type of molecule could result in the cell's inability to "turn off" genes?
corepressor
What bonds are found between individual amino acids that make up a polypeptide chain
covalent/peptide bonds between the N of one amino acid and the terminal C of another
How might you determine the genotype of an individual that displays a dominant phenotype?
cross it with a homozygous recessive individual
Which of the following is NOT true of alleles?
each egg/sperm can contain both alleles for a particular
What could result in a frameshift mutation?
either an insertion or a deletion of a base
DNA and histone methylation, acetylation of histones and methylation of CpG islands are all examples of?
epigenetic regulation
Which of these requires some post-transcriptional modifications to become active?
eukaryotic tRNA eukaryotic rRNA
The regions labeled A and C of the diagram are ?
exons
What are the coding segments of a stretch of eukaryotic DNA called?
exons
Genes for two different traits that are found next to each on a chromosome can end up in different gametes.
false
Which of the following is true of X-linked recessive traits?
females can carry the trait but will only show the trait if they have two recessive alleles
A tall green seeded plant (TTyy) is crossed with a short yellow seeded plant (ttYY). The F1, as expected, all show the dominant phenotype for these two traits. The F1 plants are then allowed to self pollinate. How many different phenotypes for these two traits would be expected in the F2 generation?
four
What features are shared by prokaryotic and eukaryotic cells?
genetic materials that contain information for creating cellular components ribosomes that function to synthesize proteins plasma membranes composed predominately of phospholipids
In a nucleosome, the DNA is wrapped around?
histones
The cross of two true-breeding varieties is called _______________ and results in the production of the _____ generation.
hybridization, F1
What types of bonds contribute to the formation of alpha helices and beta sheets that are found in proteins?
hydrogen bonds between amino acids in the polypeptide chains
If a true-breeding twelve inch plant (this means when self-crossed the offspring are always 12inches) is crossed with a true-breeding six inch plant and all of the F1 plants are nine inches tall, this is most likely a situation of?
incomplete dominance
Which of the following would be likely to alter the shape of a repressor and change its function?
inducer
The TATA box plays a key role in transcription, what is true of this region of the DNA?
it is found upstream of the initiation site it is found in both prokaryotic and eukaryotic promoters the instability of the A-T bonds helps the DNA template unwind
During translation, what roles does the hydrolysis of GTP molecules play?
it provides energy for the breakdown of the translation assembly it provides energy for the translocation step (movement of tRNA from the A site to the P site) it provides energy for codon recognition it provides energy for the formation of the initiation complex
The antibiotics chloramphenicol blocks peptidyl transfer in bacteria. How would this most directly affect protein synthesis in bacteria?
it would slow the growth of the peptide chain
If lactose-metabolizing enzymes are produced whether or not lactose is present, a mutation in which gene is likely to be the cause?
lac I (encodes the lac repressor protein)
What does it take to in order for the lac genes to be expressed at a high level in a bacterial cell?
lactose must be present glucose levels must be low
Which of the following is true of genetic recombination in crossing over?
maternal and paternal alleles can become combined onto the same chromosome several recombination events may occur in one chromosome
Which of the following is an example of epigenetic inheritance?
methylated patterns in the DNA that are maintained between generations
In a eukaryotic cell, where is ribosomal RNA transcribed?
nucleolus
Gametes have [x] of each pair of homologous chromosomes and therefore possess [y] of every gene.
one copy, one copy
The observable traits expressed by an organism are described as its ________.
phenotype
What molecules make up the backbone of the RNA molecule?
phosphate groups ribose sugars
The binding of eIF-2 to the RNA is controlled by?
phosphorylation
What is added to the 3'-end of many eukaryotic mRNAs after transcription?
poly A tail
Which of the following helps to stabilize mRNA by inhibiting its degradation?
poly A-tail and 5' cap
Match the term with the definition or function
polycistronic- an mRNA sequence that can code for more than one polypeptide promoter- a sequence of the DNA that binds the transcription machinery template strand- the strand of DNA that is actively transcribed into mRNA RNA polymerase- a protein that is composed of multiple subunits involved in synthesizing mRNA
What is crucial in the formation of a preinitiation complex on the DNA template that subsequently recruits RNA polymerase II for transcription initiation?
presence of basal transcription factors
How do eukaryotic chromosomes differ from prokaryotic chromosomes?
prokaryotic chromosomes are not linear eukaryotic chromosomes contain DNA that is bound to histones porkaryotic chromosomes do not contain telomeres
At what region of the DNA does RNA polymerase first bind to a gene?
promoter
Post-translational modifications of proteins can affect?
protein function
What molecules are involved in the expression of genes into proteins?
proteins RNAs
What are UTRs?
regions of the mRNA where proteins can bind that influence mRNA stability regions of the mRNA that are not translated into proteins regions that regulate mRNA localization, stability, and protein translation.
Which of the following is considered a post-translational modification of protein?
removal of terminal amino acids from the protein binding of two polypeptide strands attachment of a lipid to the protein
Alternative splicing can?
result in different versions of proteins being produced at different developmental stages be a random or a regulated process result in different proteins being made from the same gene
How is rho-dependent transcription termination different from rho-independent termination?
rho-independent termination involves the interaction between nucleotides within the newly formed mRNA strand rho-dependent termination involves the interaction of the rho protein with the RNA polymerase
RNAs that catalyze biological reactions, such as self-splicing introns, are known as?
ribozymes
Homologous chromosomes share which of the following features?
same length, centromere position and genes controlling inherited traits
Which of the following components is present in the ribosome when translation initiation is completed?
small ribosomal subunit initiator tRNA an mRNA sequence large ribosomal subunit
The primary RNA transcript of the chicken ovalbumin gene is 7700 nucleotides long, but the mature mRNA that is translated on the ribosome is 1872 nucleotides long. This size difference occurs primarily as a result of?
splicing
The antibiotic tetracycline blocks the A site on the bacterial ribosome. What direct effect would you expect tetracycline to have on bacterial protein synthesis?
tRNAs will not be able to bind to the ribosome
The "-" sign in front of a region of a gene indicates what?
that it is upstream of the gene
Before Mendel chose a particular pea character to use in his studies what did he need to know about it?
that the trait was heritable and parental plants were true-breeding
Once a gene is transcribed into mRNA in eukaryotes, what must occur before it can be used to build a protein?
the introns need to removed
A geneticist isolates a gene for a specific trait under study. She also isolates the corresponding mRNA. Upon comparison, the mRNA is found to contain 1,000 fewer bases than the DNA sequence. What is the most likely explanation for this difference?
the mRNA is shorter because the final mRNA contains only exons, the introns were removed
Which of the following is the best statement of the use of the addition rule of probability?
the probability that either one of two independent events will occur
In addition to instructing the order of addition of amino acids to a polypeptide what else do codons contain instructions for?
the start of beginning of the coding region the stop or end of the coding region
If two traits are always found together in a species then you can assume that?
these traits are found on the same chromosome
Why are the -10 and -35 regions of prokaryotic promoters referred to as consensus sequences?
they are similar in all bacterial species
Which of the following is true of codons?
they may code for the same amino acid as another codon
Which of the following nucleotides is not found in RNA strands?
thymine
What is the function of the promoter region of a gene?
to bind transcription factors that regulate transcription
Because prokaryotes do not have a nucleus, what processes can occur simultaneously?
translation RNA degradation transcription
Self-fertilization occurs when the pollen from one plant, fertilizes the egg/ovary of a flower on the same plant.
true
What did Mendel actually cross in his hybridization of pea plants?
true breeding individuals that had different traits
The tryptophan operon is a repressible operon that is?
turned off whenever tryptophan is added to the growth medium.
Where are you likely to find an enhancer of a particular gene?
upstream of the gene downstream of the gene within the coding region of the gene
The ribosomal complex has three sites where tRNA molecules bind and participate in protein synthesis. Match each site with its function in protein synthesis.
where the anticodon of the incoming tRNA base pairs with the mRNA- A site where the tRNA with the growing polypeptide strand is bound to the mRNA- P site where tRNA that have already contributed a amino acid (peptide) strand bind before leaving the ribosome- E site
Which subunit of the E. coli polymerase is involved in binding to a specific start site in the DNA promoter of a gene?
σ