$$\text{GAATTC}$$ \newline $$\text{CTTAAG}$$

$$\text{MPF activity} \propto \text{Cyclin concentration}$$

Question 1

Which of the following best describes the function of restriction enzymes in bacteria?

Accepted Answer

They cut DNA at specific nucleotide sequences to defend against viruses.

Question 2

Which equation represents the palindromic restriction site recognized by EcoRI?

Accepted Answer

$$	ext{GAATTC}$$ 
ewline $$	ext{CTTAAG}$$

Question 3

Which of the following is a major point of gene regulation in cells?

Accepted Answer

Controlling enzyme activity through feedback inhibition.

Question 4

The trp operon is an example of a repressible operon. What happens when tryptophan concentration is high?

Accepted Answer

The repressor protein binds tryptophan, becomes active, and blocks transcription.

Question 5

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

Accepted Answer

Transcription occurs only when both lactose is high and glucose is low.

Question 6

Which equation best represents the relationship between cyclin concentration and MPF activity during the cell cycle?

Accepted Answer

$$	ext{MPF activity} \propto 	ext{Cyclin concentration}$$

Question 7

Which of the following is NOT a factor that determines which genes are used in a cell at a given time?

Accepted Answer

The number of mitochondria present

Question 8

What is the primary difference between positive and negative regulation of transcription?

Accepted Answer

Positive regulation requires stimulation for transcription, while negative regulation blocks transcription of genes whose default is 'on'.

Question 9

Which of the following statements about operons is correct?

Accepted Answer

Operons are commonly found in prokaryotes and consist of a group of genes controlled by a single promoter.

Question 10

Which of the following best explains feedback inhibition in the tryptophan synthesis pathway?

Accepted Answer

Tryptophan binds to the first enzyme in the pathway, inhibiting its activity when tryptophan levels are high.

Question 11

Which of the following is a real-world application of restriction enzymes?

Accepted Answer

Cutting DNA at specific sites to create recombinant plasmids for genetic engineering.

Question 12

Which of the following is true about the lac operon when lactose is present and glucose is absent?

Accepted Answer

Allolactose binds the repressor, inactivating it, and cAMP activates CRP, allowing transcription to proceed.

Question 13

Which of the following best describes the process of translation?

Accepted Answer

mRNA is decoded by ribosomes to synthesize polypeptides.

Question 14

Which equation represents the directionality of mRNA synthesis during transcription?

Accepted Answer

$$5' \rightarrow 3'$$

Question 15

Which of the following is a characteristic of inducible operons?

Accepted Answer

They can be turned ON and are common for catabolic pathways.

Question 16

Which of the following is a plausible outcome if a restriction enzyme cuts a plasmid at two sites?

Accepted Answer

The plasmid is linearized, and two DNA fragments are produced.

Question 17

Which of the following best describes the role of transcription factors in eukaryotic gene expression?

Accepted Answer

They stimulate or inhibit the initiation of transcription by binding to promoter regions.

Question 18

Which of the following is a plausible effect of spending time in nature, according to the American Heart Association?

Accepted Answer

Reduced stress and anxiety, improved mood, and increased feelings of wellbeing.

Question 19

Which of the following is a plausible reason why cells use only 5-20% of their genes at a time?

Accepted Answer

Gene expression is regulated based on cell type, internal and external conditions, and signals from other cells.

Chapter 18 part 1

Study Guide - Practice Questions