Question 1

Each tRNA molecule has a site at one end that ________ and a site at the other end that ________.

Accepted Answer

Each tRNA molecule has a site at one end that binds to an amino acid and a site at the other end that binds to a codon of the mRNA during protein synthesis. This allows the tRNA to carry a specific amino acid to the ribosome and match it with the correct codon on the mRNA to form a polypeptide chain.

Question 2

A potential danger of a mutation to an organism is that

Accepted Answer

A mutation can cause a change in the amino acid sequence of a protein, which can then alter its function. This can have negative effects on the organism, such as making it less able to survive, reproduce, or defend itself. However, not all mutations are harmful - some can be neutral, and a few can even be beneficial. The other answer options are incorrect because mutations do not necessarily affect spacer DNA, not all mutations are fatal, and a mutation does not affect the length of introns (which are non-coding regions within genes).

Question 3

The following figure depicts a gene and two different ways that gene could be mutated.How does Mutation A differ from Mutation B?

Accepted Answer

The answer of The following figure depicts a gene and...

Question 4

The specific type of nucleic acid found in ribosomes,which are important in protein synthesis,is ________.

Accepted Answer

The answer of The specific type of nucleic acid found...

Question 5

The intermediary molecule that transmits information in a gene to a ribosome is ________.

Accepted Answer

The answer of The intermediary molecule that transmits information in...

Question 6

Which of the following is NOT a mechanism used by cells to reduce gene expression?

Accepted Answer

The answer of Which of the following is NOT a...

Question 7

The chemical structure of bisphenol A (BPA)resembles

Accepted Answer

Bisphenol A (BPA) has a chemical structure that is similar to the hormone estrogen. This similarity can allow BPA to mimic the actions of estrogen in the body, potentially disrupting hormonal and reproductive functions.

Question 8

The lac repressor stops the expression of the genes in the lac operon.It does this by binding to a gene regulatory DNA sequence that controls the expression of the genes responsible for lactose uptake and degradation.This DNA sequence is called a(n)

Accepted Answer

The gene regulatory DNA sequence that is bound by the lac repressor is called an operator. This is a specific region of the DNA that controls the expression of the genes in the lac operon.

Question 9

The lac repressor has been mutated so that its binding site for lactose has been altered to the extent that it is unable to bind to lactose.What is the likely effect of this mutation on the lac operon?

Accepted Answer

The mutation prevents the repressor from binding lactose, but it can still bind to the operator, inhibiting transcription even when lactose is present. This is because the repressor's ability to bind the operator is not affected by this specific mutation.

Question 10

A gene affects an organism's phenotype by controlling

Accepted Answer

Genes control the production of proteins, which ultimately determine an organism's phenotype. The information encoded in the DNA sequence of a gene is transcribed into RNA, which is then translated into a specific protein. This process determines the physical and biochemical characteristics of an organism.

Question 11

Translation,a process carried out by the ribosomes,occurs in the cell ________.

Accepted Answer

The answer of Translation,a process carried out by the ribosomes,occurs...

Question 12

The genes that control lactose utilization (its uptake and degradation)in bacteria are arranged sequentially in the bacterial chromosome under the control of a single promoter sequence.This arrangement of genes is called a(n)

Accepted Answer

The arrangement of genes controlling lactose utilization in bacteria is known as an operon. This operon is regulated by a single promoter sequence, which controls the expression of all the genes in the operon. This allows for coordinated regulation of lactose utilization in bacteria. Option A is incorrect because an operator is a DNA sequence where a repressor binds to prevent transcription. Option B is incorrect because exelon is not a term used in genetics. Option D is incorrect because promoton is not a term used in genetics.

Question 13

If X is a base that is inserted into each of the following DNA sequences,on which of them is it most likely to have the greatest effect on the gene's protein product?

Accepted Answer

The answer of If X is a base that is...

Question 14

A tRNA molecule produced in a laboratory has the anticodon for the amino acid serine,but carries the amino acid leucine.When it reaches the serine codon on a molecule of mRNA where translation is under way,what is the most likely outcome?

Accepted Answer

The tRNA molecule carrying the wrong amino acid will bind with the codon on the mRNA molecule, resulting in the incorporation of an incorrect amino acid into the growing polypeptide chain. This can lead to the production of a potentially dysfunctional protein.

Question 15

The lac repressor has been mutated so that its binding site for the operator has been altered to the extent that it is unable to bind to the operator.What is the likely effect of this mutation on the lac operon?

Accepted Answer

With the binding site for the operator altered, the repressor will be unable to bind to the operator, and the lac operon will be activated by RNA polymerase, turning it on.

Question 16

When one base is changed to another at a single position in the DNA sequence of a gene,the result is a(n)________ mutation.

Accepted Answer

When one base is changed to another at a single position in the DNA sequence of a gene, the result is a substitution mutation. The other options (insertion, deletion, and frameshift) involve the addition or deletion of one or more bases, resulting in a shift in the reading frame and potentially altering multiple amino acids in the protein sequence.

Question 17

It is possible for a mutation to occur and yet not alter the end product of translation if

Accepted Answer

If the new codon resulting from the mutation still codes for the same amino acid, the end product of translation will not be affected. This is because multiple codons can code for the same amino acid, and the genetic code is redundant.

Question 18

Most molecules of RNA are ________-stranded.

Accepted Answer

The answer of Most molecules of RNA are ________-stranded....

Question 19

For a firefly to glow,the enzyme luciferase must catalyze a chemical reaction in the cells of the firefly.A scientist uses a chemical to induce a mutation in the luciferase gene in a strain of fireflies.Which of the following is true?

Accepted Answer

The mutation induced in the luciferase gene may alter the structure of the luciferase protein, which could affect its function as an enzyme. Therefore, the ability of the firefly to glow may or may not be affected by the mutation. Option A is incorrect because a change in the structure could affect the function of the protein. Option C is incorrect because a mutation in the gene can affect both the mRNA and protein structure. Option D is incorrect because not all mutations result in non-functional proteins.

Question 20

If a particular segment of DNA has the base sequence TAC,what will be the base sequence of the anticodon of the tRNA that carries the amino acid encoded by that stretch of DNA?

Accepted Answer

The anticodon of the tRNA that carries the amino acid encoded by the DNA sequence TAC would be complementary and antiparallel to the DNA sequence. RNA uses uracil (U) instead of thymine (T). Therefore, the anticodon would be UAC.

Quiz 12: From Gene to Protein

Each tRNA molecule has a site at one end that and a site at the other end that .