Question 1

What is a phenotype?

Accepted Answer

A phenotype is a set of observable traits that result from an individual's genotype and the interaction with the environment.

Question 2

What is the most likely cause of a disorder if both monozygotic and dizygotic twins show a high concordance rate?

Accepted Answer

A high concordance rate in both monozygotic and dizygotic twins suggests that shared environmental experiences are likely contributing to the disorder, as both types of twins would share similar environments.

Question 3

In the autonomic nervous system, increased arousal and energy expenditure are associated with activation of the

Accepted Answer

Increased arousal and energy expenditure are characteristic of the fight or flight response, which is mediated by the sympathetic nervous system. The somatic nervous system controls voluntary movements and the central nervous system includes the brain and spinal cord. The parasympathetic nervous system is associated with rest and digest functions.

Question 4

Your neighbor is a behavior geneticist. When you ask her to describe her discipline, what is she likely to say?

Accepted Answer

Behavior genetics is a broad approach that studies genetic influences on behavior. It focuses on the role of genetic and environmental factors in individual differences, as well as the interaction between genetic and environmental factors. It does not solely focus on specific genes or biochemical abnormalities, but instead takes a more integrated approach to understanding the complex interplay between genes and environment in shaping behavior.

Question 5

Genes are all of the following EXCEPT

Accepted Answer

Genes are not composed of proteins; rather, they are sequences of nucleotides (the building blocks of DNA) that code for proteins.

Question 6

Which of the following would be most likely to be observed in a patient whose thyroid gland is secreting too much of the hormone thyroxin?

Accepted Answer

Excess thyroxine leads to hyperthyroidism, which is characterized by symptoms such as agitation and anxiety, weight loss, sweating, and rapid heartbeat. None of the other options are associated with hyperthyroidism.

Question 7

Suppose that researchers discover the gene responsible for manic behavior. Assume that the alleles of the gene are represented by M and m and the gene is dominant/recessive. Which of the following represents the phenotype?

Accepted Answer

The phenotype in this scenario is the observable trait or behavior associated with the gene, which in this case is manic behavior. Therefore, the correct answer is choice C. The alleles (M and m) are the genetic variations responsible for the phenotype and not the phenotype itself.

Question 8

Most theories developed by behavior geneticists to pin down genetic explanations for abnormal behavior assume that mental disorders are most likely

Accepted Answer

Most theories developed by behavior geneticists assume that mental disorders are polygenic, meaning they are caused by multiple genes. This is because mental disorders are complex traits that likely involve the interaction of many genes and environmental factors. The idea that a single gene can cause a mental disorder is rare, and even in cases where a single gene is implicated, there are often other genetic and environmental factors involved.

Question 9

Similar concordance rates for a given trait in monozygotic (MZ) and dizygotic (DZ) twins suggests that the trait may be due to

Accepted Answer

Similar concordance rates in MZ and DZ twins suggest that the trait is likely influenced by environmental factors, as MZ twins share more genetic material than DZ twins. If genetics were the primary cause, MZ twins would have a higher concordance rate.

Question 10

Genes have alternative forms known as

Accepted Answer

Alternative forms of genes are known as alleles. Phenotypes refer to observable traits or characteristics, genotypes refer to the genetic makeup of an individual, and genosomes are not a recognized term in genetics.

Question 11

In a study of twins, a researcher finds that 40 percent of dizygotic (DZ) twins and 40 percent of monozygotic (MZ) twins share a trait. What is the researcher most likely to conclude about the trait?

Accepted Answer

If both DZ and MZ twins share the trait at the same rate, it suggests that genetics does not play a significant role in determining the trait, as MZ twins share more genetic material than DZ twins.

Question 12

In twin studies the key comparison involves determining how many pairs of twins either have the same disorder or are free of the disorder; this involves the calculation of

Accepted Answer

Concordance rates are used in twin studies to determine the level of similarity between twins in terms of a particular trait or disorder. In the case of twin studies focusing on disorders, the key comparison is often between twins who have the disorder (concordant pairs) and those who do not (discordant pairs), which allows researchers to distinguish between genetic and environmental contributions to the disorder.

Question 13

As more genes are involved in determining a trait, what happens to the distribution of the trait in the general population?

Accepted Answer

As more genes are involved in determining a trait, the distribution of the trait tends to follow a normal distribution, with a bell-shaped curve. This is because a large number of genes with small effects contribute to the trait, resulting in a continuous variation in the population.

Question 14

The major problem with family incidence studies that ask whether diseases "run in families" is that even when they find a higher prevalence of a certain illness in families with one ill proband

Accepted Answer

Family incidence studies cannot distinguish between genetic and environmental factors, as both can contribute to the higher prevalence of illness in families.

Question 15

If you focused your research efforts on problems associated with psychophysiological arousal, you would be interested in activity in the

Accepted Answer

Psychophysiological arousal is related to the activity of the endocrine system, which is responsible for the secretion of hormones that regulate various bodily functions including stress response, heart rate, and blood pressure. Research in this area would aim to understand the mechanisms underlying the relationship between arousal and the endocrine system.

Question 16

The endocrine system is a collection of

Accepted Answer

The endocrine system consists of a collection of glands that produce and secrete hormones into the bloodstream, which regulate various bodily functions and processes. The other answer options - neurons, ventricles, and brain structures - are not included in the endocrine system.

Question 17

What is another name for a proband?

Accepted Answer

A proband is also known as the index case, meaning they are the first individual in a family or population to develop a particular condition or disease that prompts investigation of possible hereditary factors. Choice A (carrier) refers to an individual who carries a gene for a certain genetic disorder but may not show any symptoms, and choices C and D (identical and fraternal twins) refer to siblings born at the same time.

Question 18

Theories that attempt to link psychophysiology to the etiology of psychopathology have implicated

Accepted Answer

Theories that link psychophysiology to the etiology of psychopathology have implicated both overarousal and underarousal.

Question 19

Chemical substances that affect the functioning of distant body systems and sometimes act as neuromodulators are known as

Accepted Answer

Hormones are chemical substances secreted by glands in the endocrine system that travel through the bloodstream to affect distant body systems. They are involved in many processes such as growth and development, metabolism, and reproductive functions. Some hormones also act as neuromodulators, affecting the activity of neurons in the brain. Ventricles are fluid-filled spaces in the brain and not related to hormone function. Endocrines is not a commonly used term in biology.

Question 20

What are the two components of the central nervous system?

Accepted Answer

The central nervous system (CNS) consists of the brain and the spinal cord.

Quiz 2: Causes of Abnormal Behavior