Deck 4: Descent With Modification: Dna Replication and Mutation

Question 1

Match the missing words in the following phrase. Darwin's principle of 'descent with modification' describes the balance between fitness and [A]. Natural [B] are acted on by [C], favoring individuals with the best [D] for that particular environment.

Answer 1

a. A = diversity
b. B = variations
c. C = selection
d. D = fitness

Question 2

The Meselson-Stahl experiment used DNA containing ¹⁴N and ¹⁵N to show that DNA replication is semi-conservative. If replication had been conservative (i.e., one double helix formed of 'old' DNA, and one completely new double helix), what would have been the expected outcome of the experiment after one round of replication?

A) Half the DNA would have ¹⁴N density and half would have ¹⁵N density.
B) All the DNA would have¹⁴N density
C) All the DNA would have¹⁵N density
D) All the DNA would have density intermediate between¹⁴N and ¹⁵N

Answer 2

Half the DNA would have ¹⁴N density and half would have ¹⁵N density.

Question 3

What holds the two strands of the DNA double helix together?

A) Hydrogen bonds
B) Ionic bonds
C) Covalent bonds
D) Van der Waals forces

Answer 3

Hydrogen bonds

Question 4

Using the following DNA as template, the sequence of the newly-synthesized strand is 5'______________3'
Template DNA: 5'ACGTAGCACATGACT3'

Question 5

Which enzyme separates the strands of the DNA double helix during replication?

A) DNA helicase
B) DNA polymerase
C) DNA ligase
D) RNA polymerase

Question 6

Match the missing words in the following phrase. Single nucleotides are added to a growing nucleotide chain during DNA synthesis. A covalent [A] bond is formed between the [B] carbon on [C] of the nucleotide at the end of a DNA chain and [D] on the [E] carbon of an incoming nucleotide.

Question 7

Which of the statements about replication and replication origins in eukaryotes and bacteria are true? Please select all that apply.

A) Replication origins in both bacteria and eukaryotes are A-T rich
B) Eukaryotic chromosomes have multiple replication origins
C) Bacterial chromosomes have a single origin of replication
D) Eukaryotic replication is faster than bacterial replication

Question 8

Which of these are found at a replication fork? Please select all that apply.

A) DNA polymerase
B) DNA helicase
C) Double-stranded DNA
D) Single-stranded DNA

Question 9

What is the function of primase?

A) To synthesize RNA
B) To replicate DNA
C) To separate the DNA double helix
D) To copy the ends of chromosomes

Question 10

During DNA replication, the leading strand of the separated double helix is synthesized using continuous replication. The lagging strand is synthesized using discontinuous replication.

Question 11

Where is the next nucleotide added to the growing chain during DNA replication?

A) 3' hydroxyl
B) 3' phosphate
C) 5' hydroxyl
D) 5' phosphate

Question 12

What are Okasaki fragments?

A) DNA pieces made on the lagging strand
B) Small proteins that protect single-stranded DNA from re-annealing.
C) Small RNA fragments that prime DNA synthesis
D) Proteins that join DNA together

Question 13

Match the missing words in the following phrase. [A] relieves supercoils ahead of the replication fork, then [B] unwinds the double helix. [C] synthesizes DNA, and [D] joins discontinuous pieces of DNA together.

Question 14

The leading strand is more severely affected by the end-replication problem than the lagging strand.

Question 15

What do reverse transcriptases do?

A) Copy RNA into DNA
B) Copy DNA into RNA
C) Copy DNA into DNA
D) Copy RNA into RNA

Question 16

Which of the statements about replication error and repair during DNA synthesis are true? Please select all that apply.

A) The error rate during DNA replication is approximately 100-fold higher than the error rate after proofreading
B) DNA polymerases can have 3' endonuclease activity
C) Error-prone polymerases do not have proofreading capacity
D) Base tautomerization can lead to non-Watson-Crick base pairing

Question 17

How do bacteria determine which is the newly-synthesized DNA strand during mismatch repair?

A) The new DNA strand is not methylated
B) The new DNA strand contains phosphate
C) MutH protein is bound to the new DNA strand
D) MutS protein recognizes the mismatched bases

Question 18

Match the DNA alteration to its description.

-pyrimidine replacement with a purine

A) Transversion
B) Indel
C) Transition
D) SNP

Question 19

Match the DNA alteration to its description.

-sequence change involving several bases

A) Transversion
B) Indel
C) Transition
D) SNP

Question 20

Match the DNA alteration to its description.

-purine replacement with a purine

A) Transversion
B) Indel
C) Transition
D) SNP

Question 21

Match the DNA alteration to its description.

-base change at a single nucleotide

A) Transversion
B) Indel
C) Transition
D) SNP

Question 22

Which of the mutation types is least likely to have a phenotypic effect?

A) Missense
B) Frameshift
C) Nonsense
D) All the mutation types are equally likely to have a phenotypic effect.

Question 23

Match the missing words in the following phrase: Somatic mutations can give rise to cancer. Genes that encode proteins that stop cells dividing uncontrollably are called [A]. Mutations that [B] the amount or activity of the resultant proteins can lead to cancer. Genes encoding proteins that promote cell division are called [C]. Mutations that [D] the amount or activity of the resultant proteins can lead to cancer.

Question 24

Which of the following statements about evolution is true?

A) Neutral mutations are maintained in the population
B) An adaptive change is a beneficial mutation that arises in response to the needs of a particular environment
C) Adaptive mutations are subject to purifying selection
D) Deleterious mutations increase in the population

Question 25

Which of the following terms describes the evolutionary history of a group of organisms?

A) Phylogeny
B) Cladogram
C) Descent with modification
D) Selection

Question 26

Both rooted and unrooted phylogenetic trees show the relationships between organisms, but only rooted trees indicate the relative divergence times from the common ancestor of all organisms in the tree.

Question 27

Match the missing words in the following phrase. Different types of phylogenetic trees are used for different purposes. [A] do not estimate the amount of change between organisms. In [B], branch lengths represent the amount of difference between organisms. [C] are similar, but have the terminal [D] the same distance from the [E], which is useful for showing changes over time.

Question 28

Match the missing words in the following phrase. In linear chromosomes, replication of the [A] end can be completed without any issues, but replication of the [B] end is more problematic as the extreme end has an unfinished gap. The ends of [C] chromosomes have a [D], which consists of many repeats of a short DNA sequence. [E], which is a type of [F], binds to the repeat sequence and adds more copies of the repeat sequence to the end of the chromosome, which then allows an RNA primer to be added and DNA synthesis of the strand to continue as normal.