Module 4 Flashcards
Which of the following is most likely the number of base pairs in a bacterial chromosome? 4,000,000 4,000 400 40
4,000,000
Where are prokaryotic chromosomes located?
In the cytosol
What is a plasmid?
Extrachromosomal DNA
A histone uses what kind of bond with eukaryotic DNA to stabilize it?
An ionic bond
What is found in four forms, each with a deoxyribose sugar, a phosphate and a base?
A nucleotide
What molecule functions as a proofreader for newly replicated DNA?
DNA polymerase III
What is methylation?
The addition of -CH3 to a cytosine nucleotide after DNA replication
In translation, the site where tRNA leaves the ribosome is called what?
The E site
Which test uses auxotrophs and liver extract to reveal mutagens?
The Ames test
What is the method of DNA repair that involves enzymes that recognize and correct nucleotide errors in unmethylated DNA?
Mismatch repair
What are three mechanisms of genetic transfer between cells?
Transduction
Transformation
Conjugation
Cells that can take up DNA from their environment are considered?
Competent
Conjugation requires what, extending from the surface of a cell?
Sex pilus
What are called jumping genes?
Transposons
What is the process called when two unrelated cell exchange DNA and incorporate it into their chromosome?
Horizontal gene transfer
What does transcription produce?
RNA molecules from DNA molecules
What is a nucleotide made of?
A five carbon sugar, a nitrogen base and a phosphate
In DNA forms how many hydrogen bonds does adenine share with which other base?
Two hydrogen bonds with thymine
A sequence of nucleotides made during replication of a lagging DNA strand is called?
An Okazaki fragment
What are the three components of an operon?
- operator
- promoter
- gene
repressible operons are important in regulating prokaryotic what?
RNA transcription
What is part of each molecule of mRNA?
A codon
Ligase plays a major role in what?
The replication of lagging strands
What three characteristics must a mutation have before it can affect a population permanently?
It must be lasting, beneficial and inheritable
The trp operon is repressible, meaning that it is usually in what state and controlled by what?
it is usually in an active state and controlled by repressor
The three steps in RNA transcription are?
- initiation
- elongation
- termination
A triplet of mRNA nucleotides that specifies a particular amino acid is called what?
A codon
What are the three effects of a point mutation?
- silence
- missense
- nonsense
Insertions and deletions in a genetic code are also called what?
Frameshift mutations
What kind of operons are inactive until the substrate of their genes’ polypeptides is present?
Inducible
Why is DNA replication considered semiconservative?
Because a daughter DNA molecule is made of one new strand and one original strand
What are nucleotide sequences containing palindromes and genes for proteins that cut DNA strands?
Transposons
What is a recombination event that occurs during gamete formation in eukaryotes?
Crossing over
What kind of RNA carries amino acids
Transfer RNA (tRNA)
What two kinds of RNA are antisense, in that they are complementary to another nucleic acid molecule?
- Small interfering RNA
2. Micro RNA
What does recombinant DNA technology accomplish?
The modification of an organism’s genome
What is DNA synthesized from an RNA template?
Complementary DNA
After Penicillium were exposed to agents X, Y and Z and examined the type/amount of penicillin the fungi produced to find the most effective. Agents X, Y and Z were probably?
Mutagens
What recombinant DNA technique is used to replicate copies of a DNA molecule?
PCR
What technique is most useful in following gene expression in a yeast cell?
DNA microarray
What do restriction enzymes do?
Cut DNA at a specific nucleotide sequence
What application of recombinant DNA technology involves replacing a non-functional, mutated gene with a functional one?
Gene therapy
What does a DNA microarray consist of?
Single-stranded DNA localized on a substrate
What cuts DNA at specific sites?
Restriction enzymes
What process separates molecules based on their size, shape and electrical charge?
Electrophoresis
What kind of fusion is often used in the genetic modification of plants?
Protoplast fusion
Gel electrophoresis is used in what process?
Southern blotting
How do genetic changes help modern bacteria?
- bacteria have been the recipients of genetic engineering.
- bacteria can thrive everywhere.
- bacteria multiply rapidly allowing for genetic changes to appear quickly.
A bacterium’s genome consists of?
the complete set of genetic information.
How does a long circular chromosome fits into a small E. coli cell?
- by the DNA double helix twisting on itself like a wound-up rubber band
- by using nucleoid associated proteins for packing
- by supercoiling
The genetic information carried on a plasmid can be used for?
- bacteriocin synthesis.
- antibiotic resistance.
- transfer of genetic material.
The base sequence of a messenger RNA molecule that is complementary to the sequence CGTTAGA would be expressed as?
GCAAUCU.
Transcription acts to?
produce RNA molecules.
Which codon matches to the tRNA anticodon TTT?
No such anticodon exists.
An mRNA stop codon codes for?
no amino acid.
What are the parts of an operon?
- Structural genes
- Operator
- Promoter
The Ames test is used to?
learn whether a chemical can induce a bacterial mutation.
Genes that are passed between parent and offspring is called?
vertical gene transfer.
Describe a F plasmid
- They contain genes for production of the pilus
- They are a double-stranded loop of DNA.
- They are found in F+ cells.
If a donor E. coli cell transfers DNA to a recipient Shigella cell what could happen?
possible transfer of antibiotic resistance
A plasmid was produced through genetic engineering that contains a gene for human insulin. Such a plasmid is called a(n)?
recombinant plasmid.
To transfer a gene into plants, transposons isolated from which bacteria are used?
Agrobacterium.
The mRNA that codes for a particular protein will have ___ nucleotides for each amino acid in the protein.
three
Mutations arising from chance events in the environment are known as __________ mutations.
spontaneous
The enzyme that seals DNA fragments together is called _______________. (2 word answer)
DNA ligase
A ______________ is a substance which induces changes in DNA bases.
mutagen
A ________________ is a closed circular piece of DNA that contains few genes which are non-essential to the cell.
plasmid
_________ is a useful tool in biotechnology that is a small slide surface on which genes or DNA segments are attached and arranged spatially in a known pattern that can be used to assess gene expression in microorganisms. (2 word answer)
DNA microarray
____________ is a technique that takes a segment of DNA and replicates it millions of times in just a few hours.
PCR
A cell that is capable of accepting DNA from the environment is called ___________.
competent
Cell contact is necessary for bacterial conjugation to occur but does not occur for what?
transduction.
