Biology chapter 14 and 15
The process of alternative ____ can produce different transcripts from the same gene in eukaryotes.
splicing
Short, repeated sequences of DNA are characteristic of
telomeres
The enzymes in the replisome are active on _____
the leading and the lagging strands
What is the nature of terminators in bacteria?
they are specific sequences in DNA
What role does the enzyme helicase play in DNA replication?
unwinds the double helix (the DNA template)
Each aminoacyl-tRNA synthetase present in a cell recognizes _____ of the 20 common amino acids.
1
____ mutations, also known as a single _____ variations change only a single base in the sequence of DNA.
1. Point 2. nucleotide
Alternative splicing allows which of the following?
A single transcript can be spliced into different mRNAs
What is a thymine dimer?
A site where 2 adjacent thymine bases become covalently cross-linked to each other
When scientists synthesized an RNA molecule made of U (polyU) and translated it in cell-free translation systems, they produced a protein made of _____.
A string of the same amino acids
In most cases, the start codon in mRNA is ____.
AUG
How was the genetic code deciphered?
By using cell-free biochemical systems to produce proteins based on synthetic mRNAs
_____ mutations are changes that alter the structure of the chromosome itself.
Chromosomal
Which of the following facilitates the reversal of damage to our hereditary material before a permanent mutation can occur?
DNA repair systems
True or false: Eukaryotic transcripts are not modified after transcription
False
What is the name of the subunit that acts as the sliding clamp, which keeps the replicating enzyme complex attached to the template in eukaryotic cells?
PCNA
The end of a bacterial transcription unit is marked by a ____.
Terminator sequence
The poly-A tail of most mature eukaryotic mRNA is found
at the 3' end of the transcript
What role does the enzyme polymerase play in DNA replication?
attaches a nucleotide to the 3' end of the DNA strand
In transcription, the DNA strand that is not copied is called the _______ strand.
coding (or sense)
The genetic code is read in groups of three nucleotide bases known as _____.
codons
Archibald Garrod concluded that patients suffering from alkaptonuria lack the _______ necessary to catalyze the breakdown of homogentisic acid
enzyme
Based on replication proteins, DNA replication in archaea is most similar to that of _____.
eukaryotes
E. coli polymerases 1, 2, and 3 have 3' to 5' _______ activity, which provided them with a proofreading function. i.e. they can remove a mis-paired base.
exonuclease
In which of the following chromosomal entities are an individual's traits specified?
genes
Eukaryotic genes may contain non-coding regions known as _____ because they interrupt the sequence of a gene.
introns
Describe what leading strand synthesis is like.
it is continuously synthesized
Describe what lagging strand synthesis is like.
it is synthesized in small fragments that are later connected
DNA replication in eukaryotic cells is complicated by the fact that eukaryotic cells have _____.
linear chromosomes
In an aging cell, the activity of telomerase would be ______
low
In the replisome, the _____ is composed of primase, helicase, and accessory proteins that prime the lagging strand.
primosome
In a bacterial transcription unit, the role of the ______ is to form a recognition and binding site for the RNA polymerase.
promoter
The function of telomeres is to ____
protect the ends of chromosomes
The DNA controlled by an origin is called a ______
replicon
The enzyme ___ can repair UV damage by binding to a thymine dimer and cleaving it, therefore restoring two thymines.
Photolyase
Griffith's experiments were important because they showed _____.
That the genetic material could be passed from one cell to another (the transformation in bacteria)
The results of the Hershey and Chase experiments suggested that DNA was the genetic material because ____
radioactive bacteriophage DNA was found in the cytoplasm of bacterial cells
What role does the enzyme gyrase play in DNA replication?
relieves coiling in DNA strands ahead of the replication fork
The DNA structure proposed by Watson and Crick involves ____
-A helical structure -A sugar phosphate backbone -Two grooves (major and minor) (also known as a double stranded structure)
The two main eukaryotic DNA polymerases that extend DNA are
-Delta -Epsilon
Place the types of mutations found in humans in the correct order going from most frequent to least frequent.
-SNV mutations -Indels -Mobile element insertion -CNV mutation
____ repair systems target a single kind of lesion in DNA and repair only that damage, while _____ repair systems use a single mechanism to repair multiple kinds of lesions in DNA
1. Specific 2. Non specific
Consider a double stranded DNA molecule. In complementary base pairing. A pairs with _____ and C pairs with ______.
1. T (Thymine) 2. G (Guanine)
During gene expression, the DNA-to-RNA step is known as ________, while the RNA-to-protein step is known as _________.
1. Transcription 2. Translation
An ______ cuts DNA internally and an _____ cuts at the ends of DNA
1. endonuclease 2. exonuclease
To create a functional RNA, the pre-mRNA undergoes a process known as splicing. During the splicing process, the ______ are removed and the remaining _______ are connected to each other.
1. introns 2. exons
The region containing the RNA polymerase, the DNA template, and the growing RNA transcript is called the ____ ____.
1. transcription 2. bubble
CHAPTER
15
X-ray diffraction was used to determine that the diameter of a DNA molecule is ____ nm
2
Which of these is not a modification of eukaryotic transcripts?
3' cap
A segment of DNA has the sequence 5'-ATGCCC-3'. The complementary sequence would be _____
5'-GGGCAT-3'
____ is an inherited disease and the patients with this disease produce urine that contains homogentisic acid
Alkaptonuria
Which process can produce multiple transcripts from the same gene in eukaryotes?
Alternative splicing
Who is the physician that proposed a relationship between genes and the production of enzymes in the early 1900s?
Archibald Garrod
For proteins that are targeted to the ER, where is the signal sequence usually located?
At the beginning of the protein (first several amino acids added during translation)
In their experiments, Avery, MacLeod, and McCarty isolated a substance, which had a transforming activity. Which of the following destroyed that substance's ability to transform bacterial cells?
DNA-digesting enzymes
Which of the following is a mutation that changes the structure of the chromosome itself?
Duplication
Charged tRNAs are brought to the A site in the ribosome by an elongation factor called ____.
EF-Tu
In order to bring a tRNA to the A site of the ribosome, the elongation factor EF-Tu must bind to a charged tRNA and _____.
GTP
What term can refer to gene function at the level of traits or at the molecular level?
Gene expression
The experiments with radioactively labeled phage that showed that DNA was the genetic material were preformed by _____.
Hershey and Chase
In the transcription elongation complex of eukaryotes, what is the function of the CTD?
It acts as a platform, which recruits elongation factors and RNA-modifying enzymes
In the transcription elongation complex of eukaryotes, what is the CTD made of?
It consists of 7 amino acids repeated many times
The start codon of an mRNA specifies which of the following amino acids?
Methoinine
In translation termination, stop codons are recognized by what type of proteins?
Release factors
According to recent finding on human mutation rates based on genome sequencing, what is the most common type of mutation in humans?
SNVs
DNA replication that leads to the production of double helices with one parental strand and one newly synthesized strand is consistent with _____
Semiconservative replication
When the double stranded DNA helix is unwound, two single strands of DNA are formed. These strands have to be stabilized because their hydrophobic bases are exposed to water. The proteins that stabilize the two single strands are called
Single-strand binding proteins
Identify the process the pre-mRNA undergoes to create a functional mRNA.
Splicing
Typically, the ribosome uses which AUG codon it encounters in an mRNA as a signal to start translation?
The first
Which of the following describes how proteins are targeted for translation to the rough ER?
The initial amino acid sequence of these proteins serves as a signal sequence that targets them to the rough ER
In transcription, which DNA strand has a sequence that is identical to the produced RNA?
The sense strand
DNA repair mechanisms have likely evolved because of why?
There is no way for cells to avoid exposure to mutagens1`
In prokaryotes how do translation and transcription occur?
They are coupled
Inspect the diagram of the arginine synthesis pathway in Neurospora crassa. If an arginine nutritional mutant can grow on minimal media, supplemented with ornithine, we can conclude which of the following?
This mutant has a mutation in the argE gene
Why do eukaryotic cells have multiple origins of replication?
To ensure timely replication of multiple, relatively large chromosomes
What takes place on the ribosome and is the synthesis of protein from an RNA transcript?
Translation
Which of the following refers to the RNA-to-protein step in the expression of genes?
Translation
True or false: Mutations are important starting points of evolution.
True
Which of the following sets of nucleotides is a valid mRNA codon?
UUC
Most mature eukaryotic mRNAs have a string of nucleotides referred to as a poly- _____ tail
adenylated (adenine)
Franklin determined that the structure of DNA was helical based on ____
X-ray diffraction (also known as X-ray crystallography) analysis
Prokaryotes have _____.
a single RNA polymerase
Bacterial DNA is typically replicated as ____
a single replicon
The major significance of the Hershey and Chase's experiments is that they ____
determined that DNA is the genetic material
What role does the enzyme primase play in DNA replication?
makes a 10-12 bp complementary primer to the DNA
Ribosomes cannot directly process DNA to synthesize polypeptides; they can only translate a specific type of RNA transcript, the _____ RNA
messenger (m)
_____ repair is responsible for removing bases that were incorrectly incorporated in DNA during replication
mismatch
Radiation, UV light, x-rays, and chemicals in the environment can cause mutations in DNA and are therefore referred to as _____.
mutagens
A _____ is a heritable change in the nucleotide sequence of DNA and is the source of genetic diversity leading to evolution.
mutation
The enzyme peptidyl transferase is required in the formation of ______ bonds by the ribosome.
peptide
Consider the pathway for synthesis of arginine from glutamate by neurospora crassa. A mutant for the argG gene will be able to grow on minimal media supplemented with which of the following?
-Arginosuccinate -Arginine
Which enzymes did Avery, Macleod, and McCarty use in order to identify the genetic material?
-DNA digested enzymes -Protein digesting enzymes -RNA digesting enzymes
Select the functions of the ribosome.
-Forming peptide bonds -Decoding the transcribed message
Identify the 2 subunits of a ribosome.
-Large -Small
What are components of a nucleotide?
-Nitrogenous base -Phosphate group -Sugar
The DNA backbone is composed of what?
-Phosphate groups -Sugars
Which of the following enzymes involved in DNA replication are found at the replication fork in all three types of cells (bacterial, archaeal, and eukaryotic)?
-Primase -Polymerases -Helicase -Sliding clamp -Clamp loader
List several differences in prokaryotic and eukaryotic replication.
-Structure of the chromosome (linear vs. circular) -Number of origins of replication -Complexity of enzymology
Of the following list, which 3 items are required for DNA replication
-Template -Polymerase -Nucleotides
Choose all characteristics of the transforming substance isolated by Avery, Macleod and McCarty.
-The elemental composition of the substance was very similar to that of DNA -RNA-digesting enzymes did not affect its transforming ability -Protein-digesting enzymes did not affect its transforming abilities -DNA-digesting enzymes destroyed its transforming ability
Choose all statements that accurately describe the transcription bubble.
-The growing RNA strand protrudes from the bubble -It contains an RNA-DNA hybrid, about 9 nt long -It moves along the DNA at a rate of about 50nt/sec
How do eukaryotic transcription factors help from the initiation complex?
They recruit RNA polymerase to the promoter
The universality of the _____ code is one of the strongest pieces of evidence suggesting that all living things share a common evolutionary heritage
genetic
