Question 1

Which of the following best defines a gene according to our current understanding?

Accepted Answer

A sequence of DNA that is transcribed into RNA and can have regulatory or coding functions.

Question 2

Which of the following statements correctly compares DNA and RNA?

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded.

Question 3

Which type of RNA is responsible for bringing amino acids to the ribosome during translation?

Accepted Answer

tRNA

Question 4

What is the main function of transcription in gene expression?

Accepted Answer

To copy genetic information from DNA to RNA.

Question 5

Given the DNA template strand $$5'	ext{-}ATGCGTACG-3'$$, what is the corresponding mRNA sequence produced during transcription?

Accepted Answer

$$5'	ext{-}AUGCGUACG-3'$$

Question 6

A mutation changes a codon from $$5'	ext{-}GAA	ext{-}3' to$$ $$5'	ext{-}GAG	ext{-}3' in $$the mRNA. Both codons code for glutamic acid. What type of mutation is this?

Accepted Answer

Silent mutation

Question 7

Which of the following best describes the function of the lac operon in E. coli?

Accepted Answer

It is regulated by both negative and positive control mechanisms, allowing the cell to metabolize lactose only when lactose is present and glucose is absent.

Question 8

Which of the following is an example of positive control of gene expression in prokaryotes?

Accepted Answer

The binding of CAP-cAMP complex to the promoter to enhance transcription of the lac operon.

Question 9

How does acetylation of histone proteins affect gene expression in eukaryotes?

Accepted Answer

It relaxes chromatin structure, increasing gene accessibility and promoting transcription.

Question 10

Which of the following events during meiosis increases genetic variation in offspring?

Accepted Answer

Crossing over between homologous chromosomes during prophase I.

Question 11

A cell undergoes meiosis but fails to separate homologous chromosomes during anaphase I. What is the likely result?

Accepted Answer

Some gametes will have an extra chromosome, and some will be missing one (nondisjunction).

Question 12

Which of the following best explains Mendel's Law of Independent Assortment at the chromosomal level?

Accepted Answer

Homologous chromosomes align independently at the metaphase plate during meiosis I.

Question 13

In a cross between two heterozygous pea plants ($$Yy$$), what is the expected phenotypic ratio of yellow to green seeds if yellow is dominant?

Accepted Answer

$$3:1$$

Question 14

A woman who is a carrier for a sex-linked recessive disorder (X-linked) and a man who is unaffected have a son. What is the probability that their son will have the disorder?

Accepted Answer

$$0.5$$

Question 15

Which of the following scenarios is an example of incomplete dominance?

Accepted Answer

A red-flowered plant crossed with a white-flowered plant produces pink-flowered offspring.

Question 16

Which of the following best describes a polygenic trait?

Accepted Answer

A trait influenced by multiple genes, each contributing to the phenotype.

Question 17

Which of the following is a potential societal impact of genomics research?

Accepted Answer

Increased privacy concerns due to genetic data sharing.

Question 18

Which process allows a single gene to code for multiple proteins in eukaryotes?

Accepted Answer

Alternative mRNA splicing

Question 19

A researcher finds that a certain gene is highly methylated in cancer cells but not in normal cells. What is the most likely effect of this methylation?

Accepted Answer

Decreased expression of the gene in cancer cells.

Genes, Gene Expression, Meiosis, and Patterns of Genetic Inheritance: Study Guide

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