CH 3 Summary

Question 1

gametes are produced through; other cells reproduce through

Answer 1

meiosis; mitosis

Question 2

when do the sperm’s and egg’s chromosomes merge?

Answer 2

conception

Question 3

types and amounts of chromosomes in the 46

Answer 3

22 pairs of autosomes; 1 pair of sex chromosomes

Question 4

each chromosome is a molecule of what

Answer 4

DNA

Question 5

DNA is made up of _________ _______ organized in a structure that resembles a ________ __________

Answer 5

nucleotide pairs; spiral staircase

Question 6

2 DNA nucleotide pairs

Answer 6

adenine-thymine and guanine-cytosine

Question 7

gene

Answer 7

section of DNA that provides biochemical instructions

Question 8

genotype

Answer 8

all of a person’s genes

Question 9

phenotype

Answer 9

physical, behavioral and psychological characteristics that develop when the genotype is exposed to a specific environment

Question 10

alleles

Answer 10

different forms of the same gene

Question 11

homozygous gene

Answer 11

has the same allele on a pair of chromosomes

Question 12

heterozygous gene

Answer 12

has different alleles on a pair of chromosomes

Question 13

incomplete dominance

Answer 13

person is heterozygous for that gene but the phenotype shows a mix b/w the dominant and recessive phenos

Question 14

polygenic inheritance

Answer 14

phenotype reflects combined activity of many distinct genes

Question 15

which 2 phenotypes often involve polygenic inheritance

Answer 15

behavioral and psychological

Question 16

how has polygenic inheritance traditionally been studied?

Answer 16

studying twins and adopted children, and identifying DNA markers

Question 17

nonshared environmental influences

Answer 17

family environments affect each child in the fam differently

Question 18

most inherited disorders are carried by _______ alleles

Answer 18

recessive

Question 19

some inherited disorders

Answer 19

sickle-cell disease, albinism, cystic fibrosis, PKU, Tay-Sachs disease

Question 20

why are inherited disorders rarely carried by dominant alleles

Answer 20

individuals with these disorders often don’t live long enough to have children (except Huntington’s disease)

Question 21

what happens to most fertilized eggs that don’t have 46 chromosomes after conception

Answer 21

they’re aborted spontaneously; except for Down syndrome (extra 21st chromosome)

Question 22

why are disorders of the sex chromosomes more common that autosome disorders

Answer 22

bc sex chromosomes contain less genetic material than autosomes

Question 23

sex chromosome disorders

Answer 23

Klinefelter’s syndrome, XYY complement, Turner’s syndrome, XXX syndrome

Question 24

do genes directly affect behavior

Answer 24

no

Question 25

how do genes indirectly affect behavior

Answer 25

increase the odds that a child will behave in a particular way

Question 26

the impact of a gene on behavior depends on what

Answer 26

the environment that the genetic instructions are carried out in

Question 27

passive gene-environment relation

Answer 27

parents pass on genotypes to their kids and provide much of the early environment for their young kids

Question 28

evocative gene-environment relation

Answer 28

occurs during development as the child’s genotype evokes responses from the environment

Question 29

active gene-environment relation

Answer 29

common in older children and adolescents because old individuals actively seek environments suited to their genotype

Question 30

reaction range

Answer 30

extent to which full genetic expression can occur depending on the limits imposed by the environment

Question 31

what explains that one genotype can lead to different phenotypes

Answer 31

reaction range