Biological bases of behavior and prenatal development

Question 1

genes

Answer 1

A group of nucleotide bases that provides a specific set of biochemical instructions.

Question 2

chromosomes

Answer 2

Threadlike structures in the nucleus of the cell that contain genetic material.

Question 3

alleles

Answer 3

A variation of a specific gene.

Question 4

recessive traits

Answer 4

An allele whose instructions are ignored when it is combined with a dominant allele.

Question 5

Dominant traits

Answer 5

The form of an allele whose chemical instructions are followed.

Question 6

inherited disorders

Answer 6

-most carried by recessive alleles

Question 7

genotype

Answer 7

A person’s hereditary makeup.

Question 8

phenotype

Answer 8

The physical, behavioral, and psychological features that are the result of the interaction between one’s genes and the environment.

Question 9

homozygous

Answer 9

When the alleles for a trait are the same.

Question 10

heterozygous

Answer 10

When the alleles for a trait differ from each other

Question 11

polygenic inheritance

Answer 11

When phenotypes are the result of the combined activity of many separate genes.

Question 12

What is Down Syndrome’s genetic basis?

Answer 12

Extra genetic material on chromosome 21. It is not inherited, rather it occurs as a random event during cell division early in fetal development.

Question 13

What is meant by incomplete dominance?

Answer 13

The situation in which one allele does not dominate another completely.

Question 14

How does this relate to sickle-cell anemia?*

Answer 14

A disorder in which individuals show signs of mild anemia only when they are seriously deprived of oxygen; occurs in individuals who have one dominant allele for normal blood cells and one recessive sickle-cell allele

Question 15

What is Phenylketonuria (PKU) and what is its cause?

Answer 15

• genetic disorder
• missing enzyme that converts amino acids into proteins…leading to accumulation in the body
• damages the nervous system
• causes mental retardation

Question 16

How does changing the environment offset the negative consequences of PKU?

Answer 16

-diets that avoid amino-acids help prevent PKU and detect it early

Question 17

Describe the findings of Caspi et al. (2003)’s study on the effects of polymorphism of the 5-HTT serotonin transporter and environmental variation on depressive symptoms

Answer 17

People that had the 5-HTT gene and were exposed to stressful life events had an increased chance of developing depression

Question 18

Describe the findings of Caspi et al. (2002)’s study on the effects of child maltreatment and polymorphism on the MAOA gene on antisocial behavior.

Answer 18

Children low in MAOA gene had severe antisocial behaviors if they experienced maltreatment

Question 19

What is the differential susceptibility model and what is the stress diathesis model?

Answer 19

Individuals vary in the degree they are affected by experiences or qualities of the environment they are exposed to. Some individuals are more susceptible to environmental influences than others ‐ not only to negative but also to positive ones

Question 20

in what way do the predictions from these models differ and in what way they are the same?

Answer 20

• differential susceptibly model: fixed individual; plastic/malleable individual
• stress diathesis model: resilient individual, vulnerable individual

Question 21

epigenetics

Answer 21

Study of heritable changes in gene expression that does not involve changes to DNA sequences

Question 22

epigenetics examples of how it might affect behavior

Answer 22

-estrogen receptor expression promotes parental behavior

Question 23

What is methylation and what do studies on cross-fostering tell us about its effects?

Answer 23

A process by which experience changes the expression of DNA—the genetic code is preserved but a gene is silenced by a methyl molecule

• Pups born to low maternal care mothers, and raised by high maternal care mothers: 1. have high estrogen receptor expression 2. Have high level of maternal care
• environment determines whether methylation is high or low, and if high then children are more prone to behavioral problems

Question 24

What does heritability measure?

Answer 24

A measure of the extent to which heredity contributes to individual differences in a trait for a group of people

Question 25

how is environment defined?

Answer 25

broadly

Question 26

How are “twin” and “adoption” studies used to research the impact of genes and environment?

Answer 26

These studies indicate substantial influence of heredity in many areas, including intelligence, psychological disorders, and personality