What would be the result of a cytosine base being substituted for a thymine base in a DNA segment during DNA replication?(1 point)

Question

Responses

The sequence could code for the wrong amino acid during translation.
The sequence could code for the wrong amino acid during translation.

The entire segment of DNA would be affected.
The entire segment of DNA would be affected.

The cytosine base would pair with adenine when the DNA was replicated.
The cytosine base would pair with adenine when the DNA was replicated.

There would be no effect on the DNA.
There would be no effect on the DNA.
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Answer 1

The correct response is:

The sequence could code for the wrong amino acid during translation.

This is because a substitution of a cytosine (C) for a thymine (T) in the DNA sequence can lead to the production of a different mRNA codon during transcription. If this codon codes for a different amino acid during translation, it can potentially alter the resulting protein's structure and function.

Answer 2

Which statement is the first step of protein synthesis?(1 point)
Responses

Amino acids are linked together with peptide bonds.
Amino acids are linked together with peptide bonds.

DNA unzips between the base pairs.
DNA unzips between the base pairs.

A ribosome attaches to the mRNA.
A ribosome attaches to the mRNA.

tRNA carries amino acids to the ribosome and attaches them to the mRNA strand.

Answer 3

The correct response is:

DNA unzips between the base pairs.

This statement represents the first step of protein synthesis, which involves the transcription process where DNA is unwound and unzipped to allow for the synthesis of messenger RNA (mRNA) based on the DNA template. After this step, the other processes of protein synthesis, such as ribosome attachment, tRNA carrying amino acids, and peptide bonding, can occur.

Answer 4

Which statement is true?(1 point)
Responses

Amino acids form a polypeptide chain via carbon-carbon bonds.
Amino acids form a polypeptide chain via carbon-carbon bonds.

tRNA is attached to specific proteins in the cell’s cytoplasm.
tRNA is attached to specific proteins in the cell’s cytoplasm.

Amino acids do not need to be assembled in a particular order.
Amino acids do not need to be assembled in a particular order.

The human body uses 20 amino acids to form all types of proteins.

Answer 5

The correct response is:

The human body uses 20 amino acids to form all types of proteins.

This statement is true because the human body relies on a set of 20 standard amino acids that can be combined in various sequences to form the vast array of proteins necessary for biological functions. The other statements are not accurate in the context of protein synthesis and function.

Answer 6

Which statement about cystic fibrosis is true?(1 point)
Responses

Carriers have an advantage over people who do not have the cystic fibrosis mutation.
Carriers have an advantage over people who do not have the cystic fibrosis mutation.

Cystic fibrosis is caused by a mutation in which a dominant allele replaces a recessive allele.
Cystic fibrosis is caused by a mutation in which a dominant allele replaces a recessive allele.

Cystic fibrosis affects a person’s ability to make normal red blood cells.
Cystic fibrosis affects a person’s ability to make normal red blood cells.

Cystic fibrosis is caused by a deletion of one codon in the DNA molecule.

Answer 7

The correct response is:

Carriers have an advantage over people who do not have the cystic fibrosis mutation.

This statement refers to the idea that carriers of the cystic fibrosis gene mutation (who have one copy of the mutated gene and one normal gene) may have a selective advantage in certain environments, such as in regions where malaria is prevalent. In such cases, carriers might have some increased resistance to illnesses compared to individuals without the mutation, although they do not have the disease itself.

The other statements are inaccurate:

• Cystic fibrosis is caused by a mutation in a recessive allele (not a dominant replacing a recessive).
• Cystic fibrosis primarily affects the respiratory and digestive systems, not the production of red blood cells.
• While cystic fibrosis results from a deletion in the CFTR gene, it is actually a deletion of three nucleotides (which removes one amino acid, phenylalanine) rather than just one codon affecting the entire gene product.

Answer 8

What benefit does using the CRISPR technique have in creating GMOs?(1 point)
Responses

CRISPR can result in infertile hybrids.
CRISPR can result in infertile hybrids.

It eliminates all risk of mutation.
It eliminates all risk of mutation.

Diversity within species can continue to increase through crossbreeding.
Diversity within species can continue to increase through crossbreeding.

Precise traits can be chosen to produce viable organisms more quickly.

Answer 9

The correct response is:

Precise traits can be chosen to produce viable organisms more quickly.

CRISPR technology allows for targeted editing of specific genes, enabling scientists to introduce or modify traits in organisms with high precision. This can accelerate the development of genetically modified organisms (GMOs) by allowing for more accurate adjustments to their genetic makeup while minimizing unintended changes. The other options listed do not accurately represent the benefits or characteristics of CRISPR in creating GMOs.

Answer 10

What is the phenotype of a mouse that has the genotype Bb where B is the gene for black fur and b is the gene for brown fur assuming this gene follows a Mendelian inheritance pattern?(1 point)
Responses

fur with brown hairs
fur with brown hairs

fur with both black and brown hairs
fur with both black and brown hairs

fur with black hairs
fur with black hairs

fur with yellow hairs
fur with yellow hairs
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Answer 11

The correct response is:

fur with black hairs.

In this case, "B" (black fur) is the dominant allele, and "b" (brown fur) is the recessive allele. Since the mouse has the genotype "Bb," the dominant allele "B" will dictate the phenotype, resulting in the mouse having fur with black hairs.

Answer 12

A tall, heterozygous pea plant is crossed with another tall, heterozygous pea plant.  What is the probability that an offspring will be a short plant?(1 point)
Responses

0%
0%

75%
75%

50%
50%

25%
25%
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Answer 13

The correct response is:

25%.

In this scenario, we can represent the alleles for height in pea plants as "T" (tall, dominant) and "t" (short, recessive). Since both parent plants are heterozygous (Tt), we can set up a Punnett square to determine the possible genotypes of their offspring:

       T     t
     __________
T |   TT   |  Tt  |
     __________
t |   Tt   |  tt  |

From the Punnett square, we see the following genotype ratios for the offspring:

• 1 TT (tall)
• 2 Tt (tall)
• 1 tt (short)

Out of a total of 4 possible genotype combinations, only 1 (tt) results in a short plant. Therefore, the probability of producing a short plant (tt) is 1 out of 4, or 25%.

Answer 14

Which of the following mutations would be most likely to have a harmful effect on an organism?(1 point)
Responses

a substitution of a thymine for an adenine
a substitution of a thymine for an adenine

there is not enough information to know whether a mutation would be harmful
there is not enough information to know whether a mutation would be harmful

all mutations have a harmful effect on organisms
all mutations have a harmful effect on organisms

a deletion of 3 bases near the center of a gene

Answer 15

The correct response is:

a deletion of 3 bases near the center of a gene.

A deletion of three bases can lead to the loss of a single amino acid in a protein, which may disrupt its function, especially if the deleted amino acid is crucial for the protein's activity. While a substitution of a single nucleotide (like thymine for adenine) can also be harmful, it often results in a silent mutation (no change in the amino acid) or a less severe change (missense mutation) than a significant deletion. Therefore, a deletion is generally more likely to have a harmful effect on the organism, especially if it occurs in an important region of the gene.

Answer 16

Which statement best describes why Punnett squares are useful?(1 point)
Responses

Punnett squares are used to predict all possible allele combinations and their frequencies in offspring.
Punnett squares are used to predict all possible allele combinations and their frequencies in offspring.

Punnett squares are used to predict the most likely allele combinations of the parents in a cross.
Punnett squares are used to predict the most likely allele combinations of the parents in a cross.

Punnett squares are used to predict how recessive alleles are inherited.
Punnett squares are used to predict how recessive alleles are inherited.

Punnett squares are used to predict how dominant alleles are inherited.

Answer 17

The correct response is:

Punnett squares are used to predict all possible allele combinations and their frequencies in offspring.

Punnett squares provide a visual representation of the potential genetic combinations that can result from a specific cross between parent organisms, allowing for the prediction of allele combinations and their probabilities in the offspring. This makes them a valuable tool in genetics for understanding inheritance patterns.

Answer 18

What color would a dog's fur be if its genes are aabb?

(1 point)
Responses

yellow
yellow

brown
brown

black
black

white
white
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Answer 19

The correct response is:

yellow.

In many dog breeds, the genotype "aabb" typically corresponds to a yellow coat color. The "A" and "B" alleles are often related to the black and brown colors in dogs, and when both are recessive (as in aabb), yellow fur is usually expressed.

Answer 20

Which of the following statements is most consistent with the DNA Hypothesis? The amount of DNA will generally increase from cell type to cell type as the number of:(1 point)
Responses

chromosomes in the nucleus increases from cell type to cell type.
chromosomes in the nucleus increases from cell type to cell type.

amino acids in the nucleus increases from cell type to cell type.
amino acids in the nucleus increases from cell type to cell type.

amino acids in the cytoplasm increases from cell type to cell type.
amino acids in the cytoplasm increases from cell type to cell type.

chromosomes in the cytoplasm increases from cell type to cell type.

Answer 21

The correct response is:

chromosomes in the nucleus increases from cell type to cell type.

The DNA Hypothesis suggests that the amount of DNA in a cell is closely related to the number of chromosomes present in that cell's nucleus. Different cell types can have varying numbers of chromosomes, which consequently results in differences in the amount of DNA. Therefore, as the number of chromosomes in the nucleus increases, the amount of DNA will generally increase as well.