Question 1

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

Accepted Answer

It acts as a binding site for the repressor protein, regulating transcription.

Question 2

A mutation causes the lac repressor protein to be unable to bind allolactose. What is the most likely outcome for the lac operon in the presence of lactose?

Accepted Answer

The operon will remain off because the repressor cannot be inactivated.

Question 3

Which of the following is a key difference between repressible and inducible operons?

Accepted Answer

Repressible operons are turned off by the presence of a corepressor, while inducible operons are turned on by the presence of an inducer.

Question 4

Which of the following best explains why histone acetylation generally promotes transcription?

Accepted Answer

It loosens chromatin structure, making DNA more accessible to transcription factors.

Question 5

A researcher injects bicoid mRNA into the posterior end of a Drosophila embryo. What is the most likely developmental outcome?

Accepted Answer

Anterior structures will form at both ends of the embryo.

Question 6

Which of the following mechanisms allows a single eukaryotic gene to code for multiple related proteins?

Accepted Answer

Alternative RNA splicing

Question 7

Which of the following is NOT a typical way a proto-oncogene can become an oncogene?

Accepted Answer

Gene suppression

Question 8

In the context of gene regulation, what is the primary role of microRNAs (miRNAs)?

Accepted Answer

They bind to complementary mRNA sequences to degrade the mRNA or block its translation.

Question 9

Which of the following best explains why elephants have a lower cancer rate compared to humans?

Accepted Answer

They have more copies of the p53 tumor-suppressor gene, enhancing DNA damage response.

Question 10

Which of the following statements about eukaryotic gene expression is correct?

Accepted Answer

Differential gene expression allows cells with the same genome to have different functions.

Question 11

A mutation in a homeotic gene in Drosophila results in legs developing where antennae should be. What does this illustrate about homeotic genes?

Accepted Answer

They control the identity and placement of body parts during development.

Question 12

Which of the following is a direct result of DNA methylation in eukaryotic cells?

Accepted Answer

Long-term inactivation of genes during cellular differentiation

Question 13

Which of the following best describes the role of the CRP-cAMP complex in the regulation of the lac operon?

Accepted Answer

It acts as an activator, increasing RNA polymerase affinity for the promoter when glucose is scarce.

Question 14

Which of the following is NOT a function of tumor-suppressor proteins?

Accepted Answer

Stimulating cell division

Question 15

Which of the following arrangements of exons would NOT be possible during alternative splicing of a pre-mRNA with exons 1, 2, 3, and 4?

Accepted Answer

1, 3, 2, 4

Question 16

Which of the following best explains the concept of epigenetic inheritance?

Accepted Answer

Inheritance of traits transmitted by mechanisms not directly involving changes in nucleotide sequence

Question 17

Which of the following is a likely consequence of a loss-of-function mutation in the p53 gene?

Accepted Answer

Cells with DNA damage continue to divide, increasing cancer risk.

Question 18

Which of the following is true regarding the regulation of gene expression in eukaryotes compared to prokaryotes?

Accepted Answer

Eukaryotic gene expression is regulated at multiple levels, including chromatin structure, transcription, and RNA processing.

Question 19

Which of the following best describes the role of cytoplasmic determinants in early embryonic development?

Accepted Answer

They are maternal substances that influence gene expression in the early embryo.

Question 20

Which of the following statements about the multistep model of cancer development is correct?

Accepted Answer

Multiple mutations in proto-oncogenes and tumor-suppressor genes are usually required for cancer to develop.

ch 18 study guide bio 103

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드