Mendel and the Gene Idea: Chp 14

Question 1

p generation

Answer 1

true-breeding parents in a genetic cross

Question 2

f1 generation

Answer 2

p generation offspring

Question 3

f2 generation

Answer 3

f1 generation offspring

Question 4

four concepts explaining mendel’s 3:1 inheritance pattern

Answer 4

1: alternative versions of genes cause variations in inherited characteristics among offspring
2: for each character, every organism inherits one allele from each parent
3: if the two alleles are different, then the dominant allele will be fully expressed
4: the two alleles for each character separate during gamete production

Question 5

mendels law of segragation

Answer 5

states that allele pairs separate or segregate during gamete formation, and randomly unite at fertilization

Question 6

mendels law of independent assortment

Answer 6

states that each pair of alleles will segregate independently during gamete formation

Question 7

homozygous

Answer 7

two of the same alleles

Question 8

heterozygous

Answer 8

two different alleles

Question 9

phenotype

Answer 9

refers to an organisms expressed physical traits

Question 10

genotype

Answer 10

refers to an organisms genetic makeup

Question 11

testcross

Answer 11

is done to determine if an individual showing a dominant trait is homozygous or heterozygous

Question 12

monohybrid cross

Answer 12

a cross involving the study of only one character

Question 13

dihybrid cross

Answer 13

a cross intended to study two characters

Question 14

the rule of multiplication

Answer 14

when calculating the probability that two or more independent events will occur together in a specific combination, multiply the probabilities of each of the two events

Question 15

the rule of addition

Answer 15

when calculating the probability that any of two or more mutually exclusive events will occur, you need to addd together their individual probabilities

Question 16

complete dominance

Answer 16

dominance in which the heterozygote and the homozygote for the dominant allele are indistinguishable

Question 17

co dominance

Answer 17

occurs when two alleles are dominant and affect the phenotype in two different but equal ways

Question 18

incomplete dominance

Answer 18

a type of dominance in which the F1 hybrids have an appearance that is in between that of the two parents

Question 19

multiple alleles

Answer 19

occur when a gene has more than two alleles

Question 20

pleiotrophy

Answer 20

the property of a gene that causes it to have multiple phenotypic effects

Question 21

epistasis

Answer 21

a gene at one locus alters the effects of a gene at another locus

Question 22

polygenic inheritance

Answer 22

two or more genes have an additive effect on a single character in the phenotype

Question 23

pedigree

Answer 23

a diagram that shows the relationship between parents and offspring across two or more generations. Circles represent females and squares represent males.

Question 24

recessively inherited disorders

Answer 24

require two copies of the defective gene for the disorder to be expressed

Question 25

cystic fibrosis

Answer 25

caused by a mutation in an allele that codes for a cell membrane protein that functions in the transport of chloride ions into and out of the cells. the resulting high extracellular levels of chloride cause mucus to be thicker and stickier, leading to organ malfunction and recurrent bacterial infections

Question 26

tay-sachs disease

Answer 26

is caused by an allele that codes for a dysfuntional enzyme, which is unable to break down certain lipids in the brain. as they accumulate in the brain cells, the child suffers from blindness, seizures, and degeneration of brain function, leading to death

Question 27

sickle cell disease

Answer 27

caused by an allele that codes for a mutant hemoglobin molecule that forms long rods when the oxygen levels in the blood are low these long rods cause the red blood cell to sickle, clogging small blood vessels and leading to pain, organ damage, and even paralysis

Question 28

lethal dominant alleles

Answer 28

require only one copy of the allele in order for the disorder to be expressed. usually, only late-acting lethal alleles are passed on

Question 29

huntingtons disease

Answer 29

caused by a lethal dominant allele. it is a degenerative disease of the nervous system, which usually doesn't affect the individual until he or she is over 40years old

Question 30

amniocentesis

Answer 30

occurs when the physician removes amniotic fluid from around the fetus. the amniotic fluid can be utilized to detect some genetic disorders, and the cells in the fluid can be cultured for a karyotype

Question 31

chorionic villus sampling

Answer 31

involves using a narrow tube inserted through the cervix to suction out a tiny sample of the placenta that contains only fetal cells. a karyotyp can immediately be developed from these cells