Question 1

If a molecule of mRNA is a sentence, its bases are the letters and the codons are the ____________________.

Accepted Answer

The answer of If a molecule of mRNA is a...

Question 2

A potential danger of a mutation to an organism is that

Accepted Answer

A mutation can alter the nucleotide sequence of a gene, which can lead to changes in the amino acid sequence of the protein it codes for. This alteration in the protein can cause a change in its function, which may lead to negative consequences for the organism. The other choices are incorrect because mutations can occur in coding DNA, not in spacer DNA (A); not all mutations are fatal (B); and mutations do not affect the length of introns (D).

Question 3

If a eukaryotic protein is to function properly ____________________ must be removed from the initial mRNA molecule and the remaining ____________________ must be joined together before translation.

Accepted Answer

The answer of If a eukaryotic protein is to function...

Question 4

The ____________________ is a sequence of DNA where RNA polymerase binds to begin transcription.

Accepted Answer

The answer of The ____________________ is a sequence of DNA...

Question 5

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

Accepted Answer

The answer of ____________________ is the specific type of nucleic...

Question 6

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

Accepted Answer

If the mutation involves a substitution of one nucleotide for another, it may result in a different codon being formed. However, if the new codon still codes for the same amino acid, the end product of translation will remain unchanged.

Question 7

A gene affects an organism's phenotype by controlling

Accepted Answer

Genes contain the instructions for making proteins, which are the building blocks of an organism's structure and function. Therefore, a gene controls an organism's phenotype by controlling protein production.

Question 8

If a particular stretch 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 stretch of DNA TAC will be complementary to it. Therefore, the anticodon will have the base sequence AUG. However, RNA contains uracil (U) instead of thymine (T), so the actual anticodon will be UAC. So the best choice is B.

Question 9

For a firefly to glow, the enzyme luciferase must assist 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 may or may not affect the ability of the firefly to glow. The luciferase enzyme is necessary for the chemical reaction that produces light in fireflies, and a mutation in the gene that codes for it may alter the structure and function of the protein. Whether the mutation affects the function of the protein and the ability of the firefly to glow depends on the specific nature and location of the mutation, as well as the degree to which it disrupts the enzyme's catalytic activity. It is not accurate to assume that any mutation in a gene causes the gene to stop making functional proteins or that a structural change in the protein will not impact its function. It is also possible that the mutation affects the structure of both the mRNA and the protein.

Question 10

The figure below 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 figure below depicts a gene and...

Question 11

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 12

A tRNA molecule produced in a laboratory has the anticodon for the amino acid serine, but carries the amino acid lysine. 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's anticodon corresponds to the serine codon on the mRNA molecule, indicating that the tRNA should carry the amino acid serine. However, since it is carrying lysine instead, a potentially dysfunctional protein will result. This is because the amino acid sequence in the resulting protein will be incorrect, leading to potentially severe consequences for its structure and function. Translation will not stop unless the incorrect amino acid completely disrupts the ribosome's ability to continue the process. Proofreading enzymes do exist, but they are typically involved in checking for errors in amino acid selection before tRNA molecules join the ribosome.

Question 13

For translation to begin mRNA must first bind to a ____________________.

Accepted Answer

The answer of For translation to begin mRNA must first...

Question 14

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 affect on the gene's protein product?

Accepted Answer

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

Question 15

A ____________________ is the series of bases in mRNA that specifies a single amino acid.

Accepted Answer

The answer of A ____________________ is the series of bases...

Question 16

Most molecules of RNA are ____________________-stranded.

Accepted Answer

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

Question 17

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

Accepted Answer

A substitution mutation, also known as a point mutation, is a type of mutation in which one nucleotide base is replaced with another in the DNA sequence. This can result in a change in the amino acid sequence of the protein encoded by the gene, potentially altering its function.

Question 18

____________________ is different than DNA replication in that it involves the copying of just a small portion of a chromosome rather than the entire chromosome.

Accepted Answer

The answer of ____________________ is different than DNA replication in...

Question 19

Translation occurs in the ____________________ of the cell, where ribosomes are located.

Accepted Answer

The answer of Translation occurs in the ____________________ of the...

Question 20

In humans, the herbicide atrazine helps RNA polymerase bind to the promoter of the gene for the enzyme aromatase. As a result,

Accepted Answer

Atrazine helps RNA polymerase bind to the promoter of the gene for the enzyme aromatase, which means that more RNA for aromatase is produced. This leads to an increase in the production of aromatase. Therefore, choice A is correct. Choices B, C, and D are incorrect since they all describe a decrease in the production or inhibition of aromatase, which is not the case in this scenario.

Quiz 15: From Gene to Protein