Question 1

Suppose you get into an argument about how similar humans and chimpanzees are. One point to consider is that these species share about ___ % of their genes.

Accepted Answer

We share about 98% of our genes with chimpanzees; between two unrelated humans, there is only one tenth of 1% difference in the genes.

Question 2

If you were to compare the DNA of any two unrelated people, about what percent of their DNA would be identical?

Accepted Answer

Two unrelated individuals can have up to 0.1% variation in their DNA, meaning they share 99.9% of their DNA. This is because almost all humans have the same collection of genes that make up our blueprint for life, but small variations, or mutations, occur over generations. Therefore, about 99.9% of the DNA of any two unrelated people would be identical.

Question 3

A single human gene is composed of about how many base pairs?

Accepted Answer

A single human gene can range from several hundred to several million base pairs in length.

Question 4

The structure of DNA consists of a long molecule that looks somewhat like a ladder that has been "twisted." The shape of the DNA molecule is referred to as:

Accepted Answer

DNA is a highly complex macromolecule: It is made up of many smaller molecules that are arranged in the shape of a twisted ladder called a double helix.

Question 5

Compared to earlier estimates about the total number of genes in the human genome, it now appears that there are:

Accepted Answer

The latest estimates indicate that there are slightly fewer genes in the human genome than previously thought. Earlier estimates put the number of human genes at around 100,000, but recent studies suggest that the actual number is closer to 20,000-25,000 genes.

Question 6

Which of the following is NOT contained in a nucleotide?

Accepted Answer

A nucleotide consists of three components: a base molecule, a phosphate molecule, and a sugar molecule. Enzyme is not a component of a nucleotide.

Question 7

According to research presented in the text, the genetic locations that are responsible for determining a person's race:

Accepted Answer

Research suggests that race is not a meaningful concept in a genetic sense because genetic variation is continuous and not confined to specific locations or chromosomes.

Question 8

According to the text, the human body contains about how many different types of cells?

Accepted Answer

The text states that the human body contains "more than 200 different types of cells." Therefore, option C is the correct answer.

Question 9

The text suggests that, from a genetic point of view, the concept of race is:

Accepted Answer

The concept of race is often used to categorize people into groups but this categorization becomes largely meaningless when considered from a genetic reference point. Although genes do control the development of characteristics frequently associated with race (e.g., skin color, eye shape, hair color and texture), these traits do not occur as "either-or" features; rather, they are distributed continuously throughout the human population.

Question 10

In building a house, carpenters look for instructions on a blueprint, which includes all of the information needed to construct the house. Comparing a house to a human cell, the part of the cell that contains the "blueprint" would be:

Accepted Answer

The cell's nucleus, which also is surrounded by a porous membrane, contains most of the deoxyribonucleic acid (DNA), which contains the genetic instructions that direct growth and development.

Question 11

If a researcher wanted to extract the DNA from a cell, she should look for it in the cell's:

Accepted Answer

The cell's nucleus, which also is surrounded by a porous membrane, contains most of the deoxyribonucleic acid (DNA), which contains the genetic instructions that direct growth and development.

Question 12

Current estimates note that the human genome contains about how many genes?

Accepted Answer

Current estimates suggest that the human genome contains approximately 20,000 to 25,000 protein-coding genes.

Question 13

Which of the following is NOT one of the ways by which nucleotide bases determine the specific traits contained in the genetic code?

Accepted Answer

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

Question 14

DNA refers to:

Accepted Answer

DNA stands for deoxyribonucleic acid, a molecule that carries genetic information in cells. A and D are not correct as they do not accurately represent what DNA stands for. B is a made-up term and not commonly used in scientific literature.

Question 15

According to the text, the most significant thing that genes do is:

Accepted Answer

The text states that genes primarily build proteins, which are essential to the functioning of cells and therefore the entire organism. While genes also play a role in brain development and physiological regulation, these functions are secondary to their primary function of building proteins. Genes also play a role in reproduction, but this is not stated to be their most significant function in the text.

Question 16

About how many different proteins have been identified in the human body?

Accepted Answer

The human body is estimated to have around 200,000 different proteins.

Question 17

Which of the following parts of the cell provides most of its energy?

Accepted Answer

Mitochondria are known as the powerhouse of the cell because they produce the majority of the cell's energy through cellular respiration. The Golgi bodies are responsible for packaging and transporting proteins, the cytoplasm contains various organelles and helps with cellular processes, and the nucleus contains genetic material but does not directly provide energy.

Question 18

Which of the following statements about DNA is true?

Accepted Answer

The DNA molecule is elegant in that, regardless of the species, it contains only four types of bases: adenine (A), thymine (T), cytosine (C), and guanine (G).

Question 19

A gene is best defined as:

Accepted Answer

A gene is a specific segment of DNA that codes for a particular trait or function. It contains the instructions for making a specific protein, which can then affect an organism's physical characteristics or behavior. A nucleotide is a basic building block of DNA, while a nucleotide base pair is two complementary nucleotides that are paired together in the DNA double helix. All of the DNA contained on a specific chromosome includes many different genes, as well as non-coding regions and regulatory elements. Therefore, the best choice for a gene is option C.

Question 20

Dr. Johnson corrects a student who talks about "genetic racial differences" and suggests that a better term to use when talking about genetic differences among defined groups of people would be:

Accepted Answer

The usage of the term race should be questioned if it suggests that an individual belongs to a genetically defined group. A more appropriate term in a context such as this is ethnicity, which avoids the genetic connotation that race often mistakenly implies and focuses instead on the shared cultural experiences of groups that define their members as similar.

Quiz 2: Heredity and Environment