Question 1

The proteome is defined as

Accepted Answer

The proteome is the entire set of proteins that are generated or expressed by an organism's genome. Therefore, option A best describes the definition of proteome. Option B is incorrect because an individual's genotype may not necessarily result in the expression of all encoded proteins. Option C is incorrect because the proteome is not a measure of gene expression rate. Option D is incorrect because mitochondrial DNA only accounts for a small fraction of an organism's total genome and therefore cannot define the proteome of a species.

Question 2

Cystic fibrosis is a fatal lung condition that results from a recessive gene.If one parent is a healthy carrier for the condition while the other is not a carrier,what is the likely outcome for any children they might have?

Accepted Answer

If one parent is a carrier and the other parent is not, the children have a 50% chance of inheriting the gene for cystic fibrosis from the carrier parent. However, in order to develop the disease, the child must inherit a copy of the gene from both parents. Since the other parent does not carry the gene, none of the children will develop the disease. However, they will have a 50% chance of inheriting the gene and becoming carriers.

Question 3

Which of the following accurately describes the attraction of bases between strands of DNA?

Accepted Answer

A pairs with T (adenine with thymine) and C pairs with G (cytosine with guanine) through hydrogen bonding, which is fundamental to the structure of DNA.

Question 4

Most cases of colorblindness result from abnormal recessive genes located on the X chromosome that are not duplicated on the Y chromosome.Which of the following statements accurately predicts the outcome for the children of a father with typical genes and a mother with abnormal genes?

Accepted Answer

Since the mother has abnormal genes, she can only pass on the X chromosome with the abnormal gene to her children. The father can pass on either his X or Y chromosome to his children. Therefore, all of the couple's daughters will be carriers of the abnormal gene, but none of them will actually be colorblind because they have a normal X chromosome from their father. On the other hand, half of their sons will inherit the X chromosome with the abnormal gene from their mother and since there is no corresponding normal gene on the Y chromosome, they will end up being colorblind.

Question 5

A group of three bases that provides instructions for the production of a single amino acid is known as a

Accepted Answer

A group of three bases that provides instructions for the production of a single amino acid is known as a codon. The other options are not accurate in describing this specific function.

Question 6

Mutations

Accepted Answer

Mutations can have positive, negative, or neutral outcomes. Some mutations may provide an advantage in certain environments, leading to positive outcomes. Others may cause harm or disease, leading to negative outcomes. However, some mutations may have no effect on the individual's survival or reproduction, resulting in neutral outcomes. Mutations may be dominant or recessive, but this does not determine whether they have a positive or negative outcome.

Question 7

The complexity of human beings relative to other animals is probably a result of

Accepted Answer

Research has shown that the complexity of human beings is likely due to the rate of gene expression, particularly in the brain. This allows for more complex cognitive functioning and behaviors. While humans do have more genes than some other animals, such as fruit flies, the difference is not significant enough to account for the vast differences in complexity. Similarly, while humans do have a larger number of imprinted genes compared to some other animals, it is not considered the main contributor to human complexity.

Question 8

You were recently introduced to your roommate's sibling.To your surprise,even though the siblings are the same sex,they look nothing alike.Which of the following is the best explanation of this situation?

Accepted Answer

The statement acknowledges the fact that there are a vast number of different combinations of genes possible during reproduction. Therefore, it is possible that the two siblings don't share many genes even though they are siblings of the same sex. This option seems to be the most logical explanation. Option A is incorrect as it assumes that they must have different parents. Option B is incorrect as genotype or genetic makeup doesn't change during development. Option D is incorrect as it implies that one sibling has only inherited recessive genes, which is highly unlikely.

Question 9

The passing along of genes that are physically close to one another on the same chromosome is known as

Accepted Answer

Linkage refers to the tendency for genes located near each other on the same chromosome to be inherited together. This is because they are less likely to be separated during the process of meiosis, which shuffles and recombines genetic material from the two parental chromosomes. Crossing over refers to the exchange of genetic material between homologous chromosomes during meiosis, which can create new combinations of genes. Meiosis is the process by which cells divide to produce gametes (sperm or egg cells) with half the number of chromosomes as the parent cell. Gene expression refers to the process by which genetic information is used to produce functional molecules such as proteins.

Question 10

_________ of the genes found on the X chromosome are duplicated on the Y chromosome.

Accepted Answer

Some of the genes found on the X chromosome are duplicated on the Y chromosome. While the Y chromosome is much smaller than the X chromosome and is missing many genes that the X chromosome contains, it carries a small subset of genes that are important for male development and fertility. Some of these genes have counterparts on the X chromosome, but others are unique to the Y chromosome.

Question 11

Sarah's mother has Huntington's disease,an illness that results from a dominant gene,but her father does not.What is the likelihood that Sarah herself will develop the disease?

Accepted Answer

Since Huntington's disease is caused by a dominant gene, if Sarah's mother has the disease, she must have at least one copy of the gene for it. Sarah has a 50% chance of inheriting that gene from her mother, and a 50% chance of inheriting a healthy allele from her father. Therefore, Sarah has a 50% chance of developing Huntington's disease. Option A is not correct because even though Sarah's father does not have the disease, he could still be a carrier. Option C is not correct because a person with only one copy of the gene for Huntington's disease can still develop the disease. Option D is not correct because the disease is caused by a dominant gene, so inheriting a healthy allele from her father does not affect her chance of developing the disease if she inherits a copy of the gene from her mother.

Question 12

When either a mother's or father's version of a gene is expressed,but not both,we refer to the gene as

Accepted Answer

When either a mother's or father's version of a gene is expressed but not both, we refer to the gene as imprinted. This process is called genomic imprinting and occurs when an epigenetic mark, such as DNA methylation, causes a gene to be silenced or expressed based on which parent provided the gene. This can lead to certain disorders when the gene is not properly imprinted.

Question 13

Which of the following statements about the genetic makeup of humans is true?

Accepted Answer

While humans do have unique genetic characteristics that differentiate us from other animal species, we also share a significant amount of genetic similarity with other primates. However, it is the specific combination and expression of genes that make each individual human unique, while also contributing to similarities among all humans.

Question 14

A characteristic that results from genes on the X chromosome that are not duplicated on the Y chromosomes is referred to as being

Accepted Answer

A sex-linked characteristic results from genes on the X chromosome that are not duplicated on the Y chromosome. The inheritance of such characteristics follows a distinct pattern that differs from other genetic traits. The other options (A, B, C) do not specifically describe characteristics resulting from genes on the X chromosome.

Question 15

Huntington's disease,a fatal degenerative movement disorder,results from large numbers of codon repeats in the Huntington gene located on chromosome 4.This means that the

Accepted Answer

The extra codon repeats in the Huntington gene result in the production of a protein with abnormally large amounts of the amino acid encoded by the extra codons, leading to the development of Huntington's disease.

Question 16

The human proteome is

Accepted Answer

The human proteome is unique to our species, as it consists of all the proteins expressed in human cells and tissues. Although there may be some overlap with other species, there are also many human-specific proteins and isoforms.

Question 17

Gene expression

Accepted Answer

Gene expression differs between species and in different types of cells. This is why different organisms have different physical and genetic characteristics, and why certain cells in the body perform specific functions. Additionally, gene expression can also be affected by various external factors such as environmental conditions and disease.

Question 18

A single human can produce eggs or sperm with more than _________ different combinations of his or her chromosomes.

Accepted Answer

A single human can produce eggs or sperm with more than 8,000,000 different combinations of his or her chromosomes. This is due to the random assortment of chromosomes that occurs during meiosis, the process by which gametes are formed. In addition, the process of crossing over, which occurs during meiosis, also contributes to the immense genetic diversity possible in human gametes.

Question 19

The process in which genes exchange equivalent sections of genetic material is known as

Accepted Answer

Crossing over is the process during meiosis where homologous chromosomes exchange genetic material, resulting in the formation of recombinant chromosomes with a combination of genetic material from both parents. This process leads to genetic diversity among offspring. Linkage refers to the tendency of genes to be inherited together due to their physical proximity on a chromosome. Meiosis is the process of cell division that results in the formation of gametes. Gene expression refers to the process by which genetic information is used to synthesize proteins or other functional molecules in a cell.

Question 20

Nancy and Cliff had four children who did not have cystic fibrosis,but their fifth child was born with the disease.Cystic fibrosis is carried on a recessive gene.Given what you've learned in this chapter,how could this happen?

Accepted Answer

In order for a child to have cystic fibrosis, both parents must pass on the recessive allele for the disease. It is possible for two carriers of the gene to have several children who do not inherit the allele, but eventually have a child who does inherit it. This is because each child has a 25% chance of inheriting the recessive allele from both parents, which is necessary for the disease to manifest. Therefore, it is most likely that Nancy and Cliff were both carriers of the recessive allele, but did not pass it onto their first four children. It wasn't until their fifth child that they both passed on the recessive allele, resulting in the expression of cystic fibrosis. The gender of the child is not relevant in this case.

Quiz 5: Genetics and the Development of the Human Brain