Deck 3: Seciton 1: Beginnings: Heredity and Environment

Question 1

Describe three of the surprises revealed upon the completion of the Human Genome Project.

Answer 1

Following the completion of the Human Genome Project in 2001, people were surprised to find that 1) humans have far fewer than 100,000 genes, the number often cited in the twentieth century. The total number of human genes is about 20,000. 2) The precise number of genes is unknown because 3) it is not always easy to figure out where one gene starts and another ends, or even if a particular stretch of DNA is actually a gene. 4) It is difficult to predict exactly how the genes from one parent will interact with the genes from another.

Question 2

Explain how nature and nurture can interact to result in alcoholism.

Answer 2

Nature and nurture can both contribute to a person experiencing alcoholism. In some individuals, genes (nature) can create the addictive desire to drink to excess. In addition, each human body metabolizes alcohol differently. Inherited personality traits may make alcoholism more likely, too.
The environment and social factors (nurture) are important because some environments (such as growing up with an alcoholic parent or being friends with an alcoholic) encourage a person's alcohol use.

Question 3

Describe epigenetics and explain how it could influence whether or not a person develops diabetes.

Answer 3

Epigenetics refers to the interaction between an individual's genes and the environment to determine the individual's phenotype. The environment can influence which genes get expressed in an individual's phenotype. If an individual inherits the genes associated with diabetes and then eats a poor diet or leads a sedentary lifestyle, the person will be apt to develop diabetes. Conversely, if the same person eats a good diet and leads a healthy lifestyle with plenty of exercise, he or she may prevent the expression of the diabetes gene.

Question 4

Describe how the gender of a fetus is decided at conception.

Question 5

Describe how a one-celled zygote develops into a baby with 5 trillion specialized cells due to the processes of duplication, division, and differentiation.

Question 6

Briefly describe differentiation and when it begins. Give at least two examples of cell differentiation.

Question 7

Explain how cells, proteins, deoxyribonucleic acid (DNA) molecules, chromosomes, and genes are related to each other.

Question 8

Define genotype and phenotype, explain the impact of both on an individual's traits, and give an example of each.

Question 9

Describe the difference between monozygotic and dizygotic twins and how each type is conceived.

Question 10

Explain how color blindness is inherited and why it is much more common in one gender than the other.

Question 11

What makes Down syndrome a chromosomal condition? Identify four characteristics often associated with Down syndrome.