Q: Which formula correctly represents the calculation of recombination frequency ($$RF) $$between two genes?

$$RF = \frac{\text{Number of recombinant offspring}}{\text{Total number of offspring}} \times 100$$

Question 1

Which of the following best explains why genes located farther apart on the same chromosome are more likely to undergo recombination during meiosis?

Accepted Answer

Because the physical distance increases the probability of a crossover event occurring between them.

Question 2

A researcher performs a reciprocal cross between two plants, one with a cytoplasmically inherited trait. The offspring phenotype changes depending on which parent contributes the egg. What is the most likely explanation?

Accepted Answer

The trait is inherited through the maternal cytoplasm, so the egg's cytoplasmic contents determine the offspring's phenotype.

Question 3

Which evidence supports the endosymbiotic origin of mitochondria and chloroplasts?

Accepted Answer

They possess circular genomes and bacterial-like ribosomes.

Question 4

A patient presents with muscle weakness, maternal inheritance pattern, and reduced ATP production. Genetic testing reveals a mutation in mitochondrial DNA. Which process is most directly impaired?

Accepted Answer

Oxidative phosphorylation

Question 5

Which of the following statements about DNA replication is correct?

Accepted Answer

Each daughter DNA molecule contains one parental strand and one newly synthesized strand in semiconservative replication.

Question 6

Which enzyme is responsible for relieving positive supercoiling ahead of the replication fork in bacterial DNA replication?

Accepted Answer

DNA gyrase

Question 7

During DNA replication, which strand is synthesized discontinuously and what are the resulting fragments called?

Accepted Answer

The lagging strand; Okazaki fragments

Question 8

Which formula correctly represents the calculation of recombination frequency ($$RF) $$between two genes?

Accepted Answer

$$RF = \frac{	ext{Number of recombinant offspring}}{	ext{Total number of offspring}} 	imes 100$$

Question 9

Which DNA polymerase is primarily responsible for synthesizing the leading strand in eukaryotic DNA replication?

Accepted Answer

DNA polymerase ε (epsilon)

Question 10

A scientist uses FISH (fluorescent in situ hybridization) to detect a gene on a chromosome. What is the principle behind this technique?

Accepted Answer

Labeled nucleic acid probes hybridize to complementary DNA sequences, allowing visualization of specific genes.

Question 11

Which of the following best describes the function of telomerase?

Accepted Answer

It adds repeated DNA sequences to chromosome ends using its internal RNA template and reverse transcriptase activity.

Question 12

Which component of telomerase acts as the reverse transcriptase protein?

Accepted Answer

TERT

Question 13

Which of the following distinguishes a nucleotide from a nucleoside?

Accepted Answer

A nucleotide contains one or more phosphate groups, while a nucleoside does not.

Question 14

Which of the following is a purine base found in both DNA and RNA?

Accepted Answer

Adenine

Question 15

Which bond connects the 3′ hydroxyl of one nucleotide to the 5′ phosphate of the next in a nucleic acid strand?

Accepted Answer

Phosphodiester bond

Question 16

Which of the following best explains the end-replication problem in eukaryotic cells?

Accepted Answer

DNA polymerases cannot fully replicate the ends of linear chromosomes, leading to telomere shortening.

Question 17

Which RNA class is most abundant in cells?

Accepted Answer

rRNA

Question 18

A mutation in mitochondrial DNA is most likely to affect which cellular process?

Accepted Answer

ATP production

Question 19

Which experiment provided direct evidence that DNA, not protein, is the genetic material in bacteriophages?

Accepted Answer

Hershey and Chase used radioactive phosphorus to label DNA and radioactive sulfur to label protein.

Question 20

Which of the following is a key reason why mitochondrial DNA accumulates mutations more rapidly than nuclear DNA?

Accepted Answer

Mitochondria lack efficient DNA repair mechanisms and are exposed to reactive oxygen species.

Genetics Exam Two Study Guide: Linkage, Extranuclear Inheritance, DNA Structure, and Replication

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