Chapter 5: Genes, Environment-Lifestyle, and Common Diseases

Question 1

Studies have identified several genes that play a role in the prevention of obesity by
affecting what?
a. Regulation of appetite 
c. Absorption of fat
b. Metabolizing of fat 
d. Altering the sense of satiety

Answer 1

ANS: A
Clinical trials using recombinant leptin have demonstrated moderate weight loss in a
subset of obese individuals. In addition, leptin participates in important interactions with
other components of appetite control, such as neuropeptide Y and
D–melanocyte-stimulating hormone and its receptor, the melanocortin-4 receptor (MC4R).
Currently, no research supports the other options as being genetically regulated.
PTS: 1 REF: Page 178

Question 2

The BRCA1 and BRCA2 mutations increase the risk of which cancer in women?

a. Ovarian
c. Uterine
b. Lung
d. Pancreatic

Answer 2

ANS: A
BRCA1 mutations increase the risk of ovarian cancer among women (20% to 50% lifetime
risk), and BRCA2 mutations also confer an increased risk of ovarian cancer (10% to 20%
lifetime prevalence). BRCA1 and BRCA2 mutations are not currently believed to be linked
with risks of lung, uterine, or pancreatic cancers.
PTS: 1 REF: Page 174

Question 3

A major characteristic of type 1 diabetes mellitus is that there is:

a. Partial insulin secretion
c. Insulin resistance
b. An autoimmune cause factor
d. Obesity as a common risk factor

Answer 3

ANS: B
A strong association between type 1 diabetes and the presence of several human leukocyte
antigen (HLA) class II alleles indicate that type 1 diabetes mellitus is an autoimmune
disease. The remaining options are associated with type 2 diabetes.
PTS: 1 REF: Page 174

Question 4

Cancers that cluster strongly in families include: (Select all that apply.)

a. Breast
b. Colon
c. Ovarian
d. Lung
e. Brain

Answer 4

ANS: A, B, C
Although breast, ovarian, and colon cancers have shown a strong familial tendency, lung
and brain cancers have not.
PTS: 1 REF: Page 172

Question 5

Examples of multifactorial diseases associated with adults include: (Select all that apply.)

a. Breast cancer
b. Coronary heart disease
c. Emphysema
d. Diabetes mellitus
e. Schizophrenia

Answer 5

ANS: A, B, D, E
Multifactorial diseases in adults include coronary heart disease, hypertension, breast
cancer, colon cancer, diabetes mellitus, obesity, Alzheimer disease, alcoholism,
schizophrenia, and bipolar affective disorder. Emphysema is not considered multifactorial.
PTS: 1 REF: Pages 171-180

Question 6

Match the terms with the corresponding descriptions.
______ A. Incidence rate effect of multiple genes
______ B. Gene-environment interaction
______ C. Prevalence rate at which some diseases occur
______ D. Obesity
______ E. Polygenic
______ F. Empirical risk
______ G. Relative risk
28. Traits caused by the combined effects of multiple genes
29. Number of persons living with the disease
30. Yields an increased risk for some diseases
31. Modifiable risk factor for many diseases
32. Number of new cases (persons) detected with the disease
33. Measure of the effect of a specific risk factor
34. Risks based on direct observation of data

Answer 6

28. ANS: E PTS: 1 REF: Page 165
    MSC: Traits in which variation is thought to be caused by the combined effects of multiple genes
    are polygenic (i.e., many genes).
29. ANS: C PTS: 1 REF: Page 164
    MSC: The prevalence rate is the proportion of the population affected by a disease at a specific
    point in time. Thus both the incidence rate and the length of the survival period in affected
    individuals determine prevalence.
30. ANS: B PTS: 1 REF: Page 171
    MSC: In some cases, a genetic predisposition may interact with an environmental factor to
    increase the risk of disease to a significantly higher level than would either factor acting alone. A
    good example of a gene-environment interaction is given by 1-antitrypsin deficiency, a genetic
    condition that causes pulmonary emphysema and is greatly exacerbated by cigarette smoking (see
    Box 5-2).
31. ANS: D PTS: 1 REF: Pages 177-178
    MSC: Obesity is a modifiable risk factor for many diseases including heart disease, stroke,
    hypertension, and type 2 diabetes.
32. ANS: A PTS: 1 REF: Page 164
    MSC: The incidence rate is the number of new cases of a disease reported during a specific period
    (typically 1 year), divided by the number of individuals in the population.
33. ANS: G PTS: 1 REF: Page 165
    MSC: A common measure of the effect of a specific risk factor is the relative risk.
34. ANS: F PTS: 1 REF: Page 167
    MSC: For most multifactorial diseases, empirical risks (i.e., risks based on direct observation of
    data) have been derived.