MICR Unit 7 Study Guide
Events that take place during the elongation phase of translation
- A peptide bond is formed between amino acids on adjacent tRNAs - Empty tRNAs leave the ribosome via the E-site - tRNAs carrying amino acids occupying the A-site and the P-site of the ribosome
Streps of how CRISPR systems
1. Cas protein complex cuts initial invading DNA into short fragments 2. Short DNA fragments are inserted into chromosomal region called CRISPR array 3. The cell transcribes the CRISPR array to produce small RNAs and called crRNAs 4. Each crRNA binds to a Cas nuclease 5. If crRNA base-pairs to invading DNA, Cas nuclease cuts the DNA
Conversion of mRNA to a protein
Translation
Insertion of DNA segments into DNA
Transposase
Deoxynucleotides
Building blocks of DNA
Transposons
Can lead to changes in genotype with a cell or between cells
Broad host range
Can replicate in many different species
Narrow host range
Can replicate in only one species
The dideoxy chain termination method is a widely used method for the sequencing of
DNA
Translation
Decoding RNA to synthesize protein
A transducing particles carries
Donor cell DNA
DNA
Essential macromolecules that contains all of the information needed by a cell to synthesize its components
True or False: An RNA transcript is a strand of RNA copied from an RNA template
False
True or false: Bacterial conjugation does not require contact between the two cells
False
True or false: In bacterial conjugation, all F+ donor cells are high frequency recombinant (Hfr) cells
False
A mutagen that causes insertions
Frameshift mutatgen
Complementary DNA produced form mature mRNA is used in cloning most eukaryotic genes, since it lacks _________
Introns
What are components of the simplest transposon, an insertion sequence?
Inverted repeats Transposase gene
A mutagen that causes the formation of highly reactive ions
Ionizing radiation
What is the importance of the polymerase chain reaction (PCR)
It can be used to detect target DNA in a sample It can be used to increase the amount of a select region of DNA in a sample
What is the fourth basic step of genetic engineering?
Ligation
Bacteria can acquire antibiotic resistance by:
Mutation Insertion of transposons Acquiring plasmids
A mutagen that causes the formation of thymine dimers
Nonionizing radiation
A mutagen that is incorporated into DNA in place of a normal base
Nucleoside analog
High copy number
Occur in many copies in a cell
Low copy number
Occur in one or a few copies per cell
What is the second step to make cDNA?
RNA processing to remove introns
What are systems bacteria can use to protect against invading DNA?
Restriction-modification CRISPR
What initiates translation?
Ribosomes assemble on the mRNA
DNA _________ involves determining the order of nucleotides in a fragment of DNA
Sequencing
Inducible
Synthesized only when needed
Plasmids
Typically do not encode genes essential to the life of the cell
Helicases
Unwind the double helix at the replication fork
When bacteriophages replicate, phage components are synthesized in the host cell and assemble into new viruses
Within that cell before being released
Replication Fork
Y-shaped on a replicating DNA molecule where the DNA polymerase is synthesizing new strands of DNA
DNA in the environment that is not contained within a cell or virus is called _____ DNA
naked
All DNA nucleotides contain the same deoxyribose and phosphate group, but different
nucelobases
A set of regulated genes transcribed as a single mRNA molecule, along with the sequences that control its expression, is called an
operon
Genomic islands that encode disease-causing factors such as exotoxins, capsules, and adherence factors are called ________ islands
pathogenicity
A virus that infects bacteria is called a
phage
After a new virus particles have assembled in the bacterial host cell, they are usually
released as a result of host cell lysis
Enzymes that are usually synthesized but are not made when they are not needed are _________ enzymes
repressible
Carries the specific amino acid to the ribosome
tRNA
In generalized transduction, donor DNA is mistakenly packaged into a phage coat, forming a __________ particle
tranducing
Most transposons contain _______________ terminators
transcriptional
Most transposons contain ______________ terminators
trasncriptional
Restriction-modification system were discovered
while studying why certain bacterial strains are relatively resistant to phage infection
Spontaneous mutations are important because
They allow populations of bacteria to adapt to a changing environment
Metagenomics is the analysis of
Total microbial genomes in an environment
Conversion of a DNA message to a RNA strand
Transcription
If you put a gene in a virus, the next step in genetic engineering would be
Transduction
Transfer of naked DNA from the environment to a recipient cell
Transformation
Roles of ribosomes in translation
- Aligning amino acids and catalyzing formation of peptide bonds between them - Ribosomes detect sequences that indicate where translation should start and finish
Steps of F plasmid transfer
1. F pilus makes contact with recipient cell 2. One strand of F plasmid is cut in origin of transfer 3. Single strand of F plasmid is transferred to the recipient cell 4. Complement of transferred strand is synthesized
The subunits of the 70S ribosomes are
50S 30S
A collection of clones that together contain the entire genome of an organism being studied is
A DNA library
Missense Mutation
A base substitution that changes the codon to one that specifies a different amino acid
Mutation
A change in DNA that is passed on to daughter cells
What is needed for the polymerase chain reaction (PCR)?
Deoxynucleotides DNA polymerase Primers Template DNA
What is needed for the dideoxy chain termination method of sequencing?
Deoxynuclotides Dideoxynucleotides Template DNA Primer DNA Polymerase
The use of an antibiotic resistance gene on a plasmid used in genetic engineering makes
Direct selection possible
Each PCR cycle _____ the number of copies of DNA
Doubles
Replication
Duplication of the genome
Taq polymerase
Enzyme that copies target DNA sequence
Reverse Transcriptase
Enzyme used to convert mature, eukaryotic mRNA into a strand of complementary DNA
True or false: An RNA transcript in the 3' to 5' direction
False
Different versions of Cas9 can be used
For gene editing To deliver molecules to certain chromosomal locations To block transcription of individual genes
A ________ mutation results from an insertion or deletion of nucleotides, leading to a shift of the reading frame from the point of mutation downstream
Frameshift
Functional unit of a genome that codes for a product
Gene
A ______ ___________ is a large segment of a cell's genome that has clearly originated in a different species
Genomic island
Sequence of nucleotides of an organism or a cell
Genotype
Enzymes that function in DNA replication
Helicase Ligase DNA Polymerase Primase
During transduction, donor DNA is injected into a recipient cell by a phage. This DNA integreates into the recipient's chromosome by
Homologous recombination
The necessary ingredients for DNA synthesis can be mixed together in a test tube. The DNA polymerase is from Thermus aquaticus and the template is from a human cell. The DNA synthesized would be most similar to:
Human DNA
Sources of "naked" DNA
Lysed (burst) bacterial cells Secreted into the environment by bacteria
Which method is not used by a cell to prevent mistakes from occurring in DNA?
Recombination
A binding protein that blocks transcription is called
Repressor
Composed of rRNA and proteins, performs translation
Ribosome
In prokaryotes, translation begins when the ribosome binds to the _________ of the mRNA
Ribosome-binding site
DNA replication is said to be __________________, because the newly made double helices are composed of one strand from the original molecule and one newly synthesized strand
Semiconservative
Primers
Short DNA molecules that determine site of amplification in target DNA
What property of a DNA fragment determines the distance it moves during gel electrophoresis?
Size
Two types of transduction
Specialized Generalized
Removal of introns
Spliceosome
Repressible
Synthesis is turned off when not needed
Primase
Synthesizes the short RNA primer
Why is Tag polymerase used in the PCR reaction?
Taq polymerase is heat-stable and can withstand the high temperature used in the denaturation step of the reaction Using heat-stable polymerase prevents the need to add more enzyme at each PCR cycle
Double-stranded DNA
Template containing target sequence
What region of DNA signals the end of an RNA transcript?
Terminator
In addition to using naturally-occurring mutants with desirable characteristics in biotechnology, researchers can now also use __________ ___ technique to genetically alter organisms
recombinant DNA
Random genetic changes that occur as a result of natural cellular processes are celled ___________ mutations
spontaneous
Staggered cuts in a double-stranded DNA molecule by a restriction enzyme leave single-stranded overhands known as _____ ends
sticky
The native or ____ _________ strain describes cells that carry non-mutated DNA
wild type
Transcription
Copying DNA into RNA
____ is transcriped from a DNA template and translated during protein synthesis
mRNA
The _________ gene pool consists of genes that can move from one DNA molecule to another
mobile
Steps involved in the dideoxy chain termination DNA termination DNA sequencing method from the beginning to the end of the process
1. DNA template, DNA polymerase, primer, deoxynucleotides and labeled dideoxynucleotides are mixed together and heated to denature the DNA 2. The reaction tubes are incubated at an appropriate temperature, facilitating primer annealing and DNA synthesis 3. DNA fragments are separated by gel electrophoresis 4. A laser is used to detect the fluorescent dyes of the dideoxucleotides 5. The DNA sequence is obtained by determining the order of the colored peaks obtained after laster analysis of the gel
Streps of DNA-mediated transformation
1. Double-stranded DNA molecule transformation into the correct order 2. Nucleases degrade one strand of double-stranded DNA at the cell surface 3.. Single-stranded DNA enters cell after one strand has been degraded 4. Single-stranded DNA integrates into genome after entering the cell 5. Stand being replaced by donor DNA is degraded
Order of events in trasnscription
1. Initiation 2. Elongation 3. Termination
Steps of polymerase chain reaction (PCR)
1. Template DNA is denatured 2. Primers anneal to denatured DNA 3. DNA synthesis occurs
Restriction enzymes are naturally produced by
bacteria
A bacterial cell describes as __________ can take up DNA from the surrounding environment
competent
Cells that have the ability to take up DNA from the environment are called _________________ cells
competent
In E.coli, about 75% of the genes are found in all strains. These conserved genes are called the _____ genome
core
In recent years, a new field of bioinformatics has emerged, which
creates the computer technology to store, retrieve, and analyze nucleotide sequence data
In bacterial conjugation, F+ donor cells are high frequency recombinant (Hfr) cells when the F plasmid
is integreated into the chromosome
What proteins are involved in the initiation of DNA replication?
DNA gyrase Helicase
Joins segments of DNA
DNA ligase
Makes a molecule of DNA from a DNA template
DNA polymerase
The molecule that contains all the instructions all the instructions needed to produce a cell's components is
DNA
Plasmids and chromosomes
Contains an origin of replication Made of double stranded DNA
Gene
A sequence of nucleotides that usually codes for one functional protein
Bacteriophage
A virus that infects bacteria, and can transfer bacterial genes from a donor cell to a recipient cell
Protein that facilitates transcription is called
Activator
DNA Polymerase
Adds nucleotides to the new chain
Restriction enzyme recognition site
Allow vector to be cut so that gene of interest can be inserted
Selective marker
Allows for elimination of bacterial cells that do not contain recombinant molecule or vector
Origin of replication
Allows plasmid to replicate independent of host chromosomes
Subunits of proteins and nucleic acid
Amino acids Nucleotides
The polymerase chain reaction (PCR) is used in
Amplifying target DNA Differential disease diagnosis
Found on the tRNA and matches the codon
Anticodon
Plasmids differ from transposons because plasmidds
Are self-replicated outside the chromosome
A mutant that requires a growth factor is an
Auxotroph
A mutagen that alters adenine so that is base-pairs with cytosine
Base-pair mutagen
Mutation rates of genes
Between one in 10,000 and one in a trillion
Chromosomes
Cells cannot survive their loss Found in all eukaryotes and prokaryotes
Proteins involved in folding newly synthesized proteins into functional structures are called
Chaperones
Found on the mRNA and codes for an amino acid
Codon
Transfer of a plasmid from a donor cell to a recipient cell
Conjugation
Constitutive
Constantly synthesized
Proteins are synthesized by translating ________ RNA
Messenger
The _____ DNA strand is used as the template for RNA synthesis
Minus (-)
Restriction enzymes were first discovered with the observation that
Phage DNA is destroyed in a host cell
The ___ strand of DNA contains the same order of nucleotides as the corresponding RNA transcript
Plus (+)
Genetic engineering has been used for what?
Produce vaccine Pharmaceutical proteins Transgenic plants, animal DNA
RNA polymerase binds to a _________ to begin transcription
Promoter
Cloning a segment of DNA into bacteria provides a readily available source of
Protein DNA
Genetically engineered bacteria have many uses, including
Protein production DNA production Research
What method is "hit and miss" - that is, does not added a specific gene to a cell?
Protoplast fusion
_ plasmids encode resistance to a variety of antimicrobial agents and heavy metals
R
Bacteriophages can consist of
RNA genome Protein coat DNA genome
In addition to separating DNA, gel electrophoresis can also separate ______________ and ___________ according to size
RNA molecules Proteins
Makes molecule of RNA from a DNA template
RNA polymerase
What enzyme binds to a DNA promoter region to initiate transcription?
RNA polymerase
While standard sigma factors recognize promoters for genes that need to be expressed during routine growth conditions, alternative sigma factors
Recognize different sets of promoters, thereby controlling expression of specific groups of genes
Transfer of genetic material from one cell to another by a bacteriophage
Transduction
Because E. coli are not naturally competent, when used for cloning, they must be treated to induce them to take up DNA by the process of
Transformation
The transfer of DNA from a donor to a recipient as naked DNA in solution is termed
Transformation
The process of decoding the information carried by mRNA to synthesize a protein
Translation
Variation in the color of corn kernels, as described by Dr. Barbara McClintock, is an example of the process called
Transposition
True or false: A point mutation involves any substitution of a single nucleotide
True
True or false: Deoxyribose is the pentose sugar in DNA
True
qPCR
Used to amplify target sequences and monitor PCR product accumulation
RT-PCR
Used to detect certain mRNA sequences in a sample
A genetic element such as a plasmid or a bacteriophage that is used to introduce genetic material into a cloning host during recombinant DNA experiments is called a
Vector
Some types of bacteria become competent
When there is a high concentration of bacterial cells When nitrogen or carbon sources are scarce
Carries the message for a polypeptide, translated by the ribosome
mRNA
When two or more DNA molecules are linked together using in vitro methods, the resuling molecule is called ________ DNA
recombinant