Question 1

Which of the following best explains why cloned animals, such as the first cloned sheep, often exhibit abnormal traits and shortened lifespans?

Accepted Answer

The cloning process fails to replicate the original organism's epigenetic modifications, affecting gene expression.

Question 2

In prokaryotes, genes for related enzymes are often organized together in operons. What is the primary advantage of this arrangement?

Accepted Answer

It allows for simultaneous transcription of multiple genes in response to a single regulatory signal.

Question 3

A mutation in E. coli impairs the ability of the lac repressor to bind to the lac operator. What is the most likely consequence for the cell?

Accepted Answer

The lac operon will be constitutively expressed, even in the absence of lactose.

Question 4

Why do nerve cells and skin cells in the same organism have different structures and functions, despite having identical genomes?

Accepted Answer

Different cell types selectively express different sets of genes through gene regulation.

Question 5

Which of the following statements about DNA packing in eukaryotic chromosomes is correct?

Accepted Answer

Tightly packed DNA around histones generally blocks gene expression by preventing access to transcription machinery.

Question 6

What must occur before RNA polymerase can bind to a promoter and transcribe a specific eukaryotic gene?

Accepted Answer

Transcription factors must bind to the DNA and facilitate the attachment of RNA polymerase.

Question 7

Alternative RNA splicing allows a single gene to produce multiple proteins. Which process is directly responsible for this phenomenon?

Accepted Answer

Selective removal and joining of exons during mRNA processing.

Question 8

If the enzyme responsible for cleaving inactive insulin is deactivated, what will be the effect on insulin in the body?

Accepted Answer

Insulin will remain in its inactive form and will not regulate blood glucose levels.

Question 9

Which of the following best describes the role of microRNAs (miRNAs) in gene regulation?

Accepted Answer

miRNAs bind to mRNA molecules and either degrade them or block their translation.

Question 10

A scientist uses a DNA microarray to analyze gene expression in cancer cells. What information can be obtained from this technique?

Accepted Answer

Which genes are turned on or off in the cancer cells compared to normal cells.

Question 11

In cell-to-cell signaling, what is the function of a signal transduction pathway?

Accepted Answer

It converts a signal received at the cell surface into a specific cellular response.

Question 12

Which statement about plant cloning and cell differentiation is supported by experimental evidence?

Accepted Answer

Differentiated plant cells retain all their genetic potential, and differentiation is mainly due to gene expression control.

Question 13

Which of the following best describes the difference between reproductive cloning and therapeutic cloning?

Accepted Answer

Reproductive cloning produces a new organism, while therapeutic cloning produces stem cells for medical use.

Question 14

Which of the following genetic changes can lead to the development of cancer?

Accepted Answer

Activation of oncogenes and inactivation of tumor-suppressor genes.

Question 15

Epithelial cells are frequently replaced and divide more often than most other body cells. Based on this information, how does their cancer risk compare to other cell types?

Accepted Answer

Epithelial cells are more likely to become cancerous due to their higher rate of cell division.

Question 16

Contrast the action of an oncogene with that of a cancer-causing mutation in a tumor-suppressor gene.

Accepted Answer

An oncogene promotes excessive cell division, while a mutated tumor-suppressor gene fails to inhibit cell division.

Question 17

Which of the following lifestyle choices can help reduce the risk of developing cancer?

Accepted Answer

Reducing exposure to carcinogens and maintaining a healthy diet and exercise routine.

Question 18

Which equation best represents the flow of genetic information in gene expression?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 19

Which process is an example of epigenetic inheritance?

Accepted Answer

Chemical modification of DNA bases or histone proteins that affects gene expression without altering the DNA sequence.

Chapter 11: How Genes Are Controlled – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard