Bio megaset

An enzyme that hydrogen bonds RNA nucleotides to the parent DNA strand in order to provide a primer for a subsequent enzyme.

Primase

The genome size of S. aureus is approximately 3X106 base pairs (bp) and can be replicated in ~2 hours. The human genome size is 3X109 bp, about 1000x times larger, and therefore should take 2000 hours (~83 days) to replicate based on the bacterial rate of replication. However, the entire human genome is replicated within few hours. Why?

Prokaryotic chromosomes have only one origin of replication compared to many origins in eukaryotes.

An enzyme that breaks the hydrogen bonds attaching the RNA nucleotides of the primer in a 5' to 3' direction and replaces the RNA nucleotides with DNA nucleotides.

DNA Polymerase I

An enzyme that hydrogen bonds DNA nucleotides based on complementary base pairing in a 5' to 3' direction.

DNA Polymerase II

The chances of cancer developing in an individual increases if a cell that has an oncogene also _____.

Has a mutation in a tumor-suppressor gene

An enzyme responsible for breaking the hydrogen bonds between nucleotide base pairs in order to open the replication fork.

Helicase

Which of these explains a commonality between distal control elements and proximal control elements.

They both can either positively or negatively control transcription

The animation below shows the ______ enzyme producing a ______ molecule during the process of _________.

RNA polymerase; mRNA; transcription

An enzyme that breaks a covalent bond in both strands of DNA periodically ahead of the replication fork to prevent supercoiling of the DNA replication.

Topoisomerase

In colorectal cancer, several types of genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated?

genes involved in regulation of the cell cycle, like proto-oncogenes and tumor suppressor genes.

When an error occurs in replication, it changes the nucleotide sequence of the DNA. This phenomenon is called a(n) _________.

mutation

Why do eukaryotic organisms transcribe intron regions when making mRNA molecules?

Introns allow for alternative splicing.

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If a researcher moves the operator to the far end of the operon, past the transacetylase (lacA) gene, which of the following processes would likely occur when the cell is exposed to lactose?

The genes of the lac operon will be transcribed continuously.

Interpreted "photo 51" and with chargaff's rules developed a working model of DNA's structure.

Watson and Crick

Which of the following occurs in prokaryotic gene expression, but does not occur in eukaryotic gene expression and how does this affect regulation of their genes?

Translation typically begins as soon as transcription has begun, even if just a little. This allows for the rapid production of proteins due to the formation of polyribosomes.

Only one nitrogenous base changes

point mutation

The nucleic acid that is a component of the ribosome.

rRNA

The purpose of a spliceosome is to:

remove introns and bring together exons in an mRNA molecule

Eukaryotic mRNA processing does NOT include which of the following?

splicing out exons

Under what conditions does the trp repressor block transcription of the trp operon?

when the repressor binds to tryptophan

Somatic cells in a human are cells than contain _____ copies of each chromosome and are considered to be ________ . Gametes are cells that contain ______ copies of each chromosome and are considered to be _______.

2, Diploid, 1, Haploid

You discover a new organism and analyze its DNA. If you find 17% of nucleotides are adenine, which of the following is true:

33% are guanine

Which strand below would be the complementary strand for the sequence 5' AAACGCTT 3'

5' AAGCGTTT 3'

When RNA polymerase synthesizes new RNA, in what direction is the new RNA formed?

5' to 3'

The following piece of double stranded DNA encodes a very short peptide. In the space below, write the sequence of mRNA that would be synthesized by RNA polymerase from this piece of DNA if the bottom strand is the template. (Include directionality with a dash and NO spaces ex)→ 5'-CCG-3' ) 5'- ATGGCTGGGTGCTTTTAA-3' 3' -TACCGACCCACGAAAATT-5'

5'-AUGGCUGGGUGCUUUUAA-3'

An RNA sequence includes 21 bases. What is the maximum number of amino acids for which this sequence could code?

7

Telomere

A repetitive sequence found in many copies on the ends of chromosomes in eukaryotes. They are present to prevent the loss of gene sequence.

A researcher is studying a specific gene (Gene WOW) located on chromosome 8. The researcher noticed that the enzyme produced from this gene didn't always have the same structure or shape. Therefore, the researcher decided to compare the gene sequence to the mature mRNA sequence that is found in the cytoplasm. They found that the gene sequence ended up producing 4 slightly different mature RNAs. How is this possible and what kind of organism's DNA was this researcher studying?

After transcription, pre-mRNA is processed by removing the introns. This allows for a process known as alternative splicing to occur that allows for different combinations of exons to be put together. The organism must be a eukaryote.

chromatid

All of the DNA on a single chromosome that gets replicated to produce a sister copy when a cell needs to go through division.

Which of these poses a challenge for DNA replication that must be overcome to allow progression of replication? Choose all that apply.

Antiparallel Orientation of DNA, Torsion, Priming

Performed an in vitro study to identify DNA as the transforming principle.

Avery, MacLeod, and McCarthy

The catabolite activator protein (CAP) is said to be responsible for positive regulation of the lac operon because ________.

CAP bound to cAMP binds to the CAP-binding site stimulating the transcription of the lac operon

Which of the following most accurately describes the anticodon?

Contains a sequence complementary to the codon.

The nucleic acid responsible for driving protein synthesis via transcription.

DNA

An enzyme that covalently bonds the 3' end of one fragment of DNA to the 5' end of the neighboring fragment of DNA.

DNA Ligase

Developed a method of x-ray diffraction imaging that could detect and visualize DNA, and are responsible for the famous "photo 51".

Franklin and Wilkins

Utilize an in vivo experiment to provide evidence that transformation occurs.

Griffith

Utilized bacteriophages to provide evidence that DNA is inherited from one generation to the next.

Hershey and Chase

Place the following in order from least condensed to most condensed. I. 300nm looped domain chromatin. II. 2nm DNA molecule. III. 30nm coiled nucleosome chromatin. IV. 1400nm replicated chromosome, only seen during cell division. V. 10nm DNA wrapped around 8 histones to form nucleosome structures. VI. 700nm condensed chromatin, only seen during cell division.

II, V, III, I, VI, IV

What is the correct order of the steps of DNA replication? I. New nucleotides are added to the template strand by DNA polymerase III. II. The DNA helix is unzipped by helicase. III. Topoisomerase creates nicks in the DNA. IV. Primase adds a RNA primer to the template strand in a 5' to 3' direction. V. RNA nucleotides are replaced with DNA nucleotides by DNA polymerase I. VI. DNA ligase forms covalent bonds between fragments in the backbone of the newly synthesized DNA strand.

III, II, IV, I, V, VI

Where does translation take place in eukaryotic organisms?

In the cytoplasm on ribosomes.

Use the sequences below to determine what type of mutation has occurred by comparing the normal sequence to the mutated sequence. Normal Gene Sequence: 3'- ATAGCTAAGCCCATGCGG-5' Mutated Gene Sequence 3'-ATAGCTAAGCCCAGGTGCGG-5'

Insertion - Frameshift Mutation

A nitrogenous base change results in a premature stop codon, resulting in a truncated protein.

Nonsense mutation

Meselson & Stahl utilized isotopes of nitrogen to determine the method of DNA replication. Based on their results, DNA replication is considered ____________ because the new replicated molecules consist of one original (parent) strand and one new (daughter) strand.

Semi-conservative

Proteins that bind to the unwound DNA and stabilize it, preventing hydrogen bonds from reforming between the base pairs.

Single Stranded binding proteins

Telomere shortening puts a limit on the number of times a cell can divide. Research has shown that telomerase can extend the life span of cultured human cells. How might adding telomerase affect cellular aging?

Telomerase eliminates telomere shortening and retards aging.

The molecule eIF-2 is involved in the initiation of translation. If this molecule does not bind to the mRNA what would happen?

The large ribosomal subunit would not be recruited and translation would not occur.

Prokaryotes often employ the use of operons. When is the lac operon at peak activity in a bacterial cell?

When lactose is present and glucose is absent.

Select the BEST answer: Cancer treatments like chemotherapy have side effects because they can target....

healthy cells.

Arrange the events taking place during transcription in order: i) The pre-RNA undergoes processing ii) RNA polymerase moves downstream, unwinding the DNA iii) RNA polymerase binds to the promoter iv) RNA transcript is released and polymerase detaches v) RNA Polymerase initiates RNA synthesis at the start on the template strand

iii, v, ii, iv, i

A researcher found a method she could use to manipulate and quantify methylation in embryonic cells in culture. In one set of experiments, she succeeded in increasing acetylation of histone tails in the chromatin of the cells. Which of the following results would she most likely see in these cells?

increase in gene expression

Given below is a list of events taking place during translation. Arrange these in proper sequence. i) The anticodon of tRNA pairs with the mRNA codon at the A site. ii) Peptide bonds form between amino group of amino acid in A site and the carboxyl end of the polypeptide in the P site. iii) Translocation of tRNA from the A site to the P site. iv) A small ribosomal subunit binds with mRNA.

iv, i, ii, iii

The nucleic acid that travels out of the nucleus carrying the code for protein synthesis into the cytoplasm.

mRNA

The nucleic acid that transports a specific amino acid to the location of protein synthesis.

tRNA

A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture?

DNA ligase

Which of these are all examples of epigenetic gene regulation?

DNA methylation, Genomic Imprinting, Histone acetylation, Histone methylation

Which of these replication elements are used for the synthesis of both the Leading and the Lagging strand during replication? Choose all that apply.

DNA polymerase I, DNA polymerase III, DNA Ligase, Primase

_______ is responsible for proofreading the DNA and fixing errors during DNA replication, while errors detected outside of DNA replication occurring are fixed through the combined effort of ________, __________, and __________.

DNA polymerase III; Nuclease, DNA polymerase, DNA ligase

What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?

DNA polymerase can join new nucleotides only to the 3′ end of a pre-existing strand, and the strands are antiparallel.

Which of the following is the correct sequence during protein synthesis and the central dogma?

DNA → transcription → mRNA → translation → protein

A premature, or unprocessed, mRNA is 5000 nucleotides (nt) long. Eventually, this mRNA will encode a protein consisting of approximately 500 amino acids (1500 nucleotides). This result is best explained by which of the following?

Introns are present in the pre-mRNA and are spliced out during pre-mRNA processing.

Which of the following is a function of a poly-A tail in mRNA?

It helps protect the mRNA from degradation by hydrolytic enzymes.

Which of the following functions does the product of the p53 gene carry out?

It inhibits the cell cycle, because p53 is a tumor suppressor gene.

Determined the structure of the nucleotide and elucidated how these monomers were linked together. Also established the tetranucleotide hypothesis.

Levene

The first scientist to successfully isolate a DNA molecule and was able show that the dominant molecule in the nucleus was not protein.

Miescher

A nitrogenous base change alters the amino acid sequence, potentially resulting in a misfolded protein.

Missense mutation

Which of the following best describes the initiation of translation?

The mRNA binds the small ribosomal subunit. The start codon is identified and a tRNA with methionine is bound to the start codon.

Imagine that you've isolated a yeast mutant that contains histones resistant to acetylation. What phenotype would you predict for this mutant?

The mutant will show decreased levels of gene expression.

Your skin cells and the cells of your liver contain the same DNA. What is the main difference between these cells?

They express different genes.

A scientist is measuring the rate of protein degradation in a cell. They know that proteins are marked with chemical tags when they need to be degraded, so the scientist measures the level of ubiquitin in the cell's cytoplasm. They notice that the amount of ubiquitin is currently elevated. What does this finding mean?

This finding likely means that the cell is in the process of degrading more protein than normal since ubiquitin is a common chemical tag for protein degradation.

Ultraviolet exposure can commonly result in which of the following forms of DNA damage?

Thymine dimer formation

If you are given a piece of DNA that is 600 base pairs long and asked to perform 20 cycles of PCR. How many base pairs of DNA will you have at the end of your PCR?

around 600Mbp

In eukaryotes, general transcription factors:

bind to other proteins or to a sequence element within the promoter called the TATA box.

Compared to heterochromatin, euchromatin is...

characterized by having actively expressed genes and comprised of loosely packed nucleosomes.

Chose the option that best completes the following sentence: Enhancers are _______________.

distant DNA sequences that are one type of distal control elements where positive regulatory proteins bind.

The genetic code is said to be redundant because

one amino acid can be encoded by more than one triplet codon.

Based on the short animation below, a _______ bond is formed between the amino acid in site _____ and the amino acid in site ______.

peptide; P; A

A complex structure consisting of rRNA and proteins that is organized into two subunits and facilitates protein synthesis.

ribosome

Which part of the DNA molecule determines an organism's genes and ultimately the associated trait?

sequence of nitrogenous bases

A nitrogenous base change does not affect the amino acid sequence, resulting in an unaffected protein.

silent mutation

A nitrogenous base is switched for a different base

substitution