A&P 29: Heredity

Question 1

Sex chromosomes

Answer 1

2 of the 46 chromosomes; determine genetic sex; male = XY; female = XX

Question 2

Autosomes

Answer 2

44 of the 46 chromosomes; guide the expression of most other traits (aside from gender)

Question 3

Karyotype

Answer 3

diploid chromosomal complement displayed in homologous pairs

Question 4

Genome

Answer 4

genetic (DNA) makeup; represents 2 sets of genetic instructions - 1 from the egg and the other from the sperm

Question 5

Homozygous

Answer 5

when the 2 alleles controlling a trait are the same

Question 6

Heterozygous

Answer 6

when the 2 alleles controlling a trait are different

Question 7

Dominant

Answer 7

allele that masks/suppresses the expression of its partner

Question 8

Recessive

Answer 8

allele being masked/suppressed

Question 9

Genotype

Answer 9

person’s genetic makeup

Question 10

Phenotype

Answer 10

the way the genotype is expressed in the body

Question 11

Segregated

Answer 11

2 alleles determining each trait are distributed to different gametes

Question 12

Independent assortment

Answer 12

alleles on different pairs of homologous chromosomes are distributed independently of each other

Question 13

Linked

Answer 13

genes on the same chromosome are said to be this because they are transmitted as a unit to daughter cells during mitosis

Question 14

Recombinant chromosomes

Answer 14

exchanging of gene segments gives rise to these chromosomes that have mixed contributions from each parent

Question 15

Crossover (chiasma)

Answer 15

break occurs between linked genes; ensures unique combo of parental genes

Question 16

Dominant-recessive inheritance

Answer 16

reflects the interaction of dominant and recessive alleles

Question 17

Punnett square

Answer 17

simple diagram used to figure out the possible gene combos that would result from the mating of parents of known genotypes for a single trait

Question 18

Incomplete dominance

Answer 18

heterozygote has a phenotype intermediate between those of homozygous dominant and homozygous recessive individuals; uncommon in humans; best human example = sickling gene(s), which cause a sub of 1 amino acid in the beta chain of hemoglobin

Question 19

Sickle-cell anemia

Answer 19

individuals with a double dose of the sickling allele (ss) have this condition

Question 20

Sickle-cell trait

Answer 20

individuals heterozygous for the sickling gene (Ss) have this trait; these individuals make both normal and sickling hemoglobin, and as a rule, are health

Question 21

Multiple-allele inheritance

Answer 21

some genes exhibit more than 2 allele forms, leading to this phenomenon

Question 22

Sex-linked

Answer 22

inherited traits determined by genes on the sex chromosomes

Question 23

X-linked

Answer 23

gene found only on the X chromosome

Question 24

Polygene inheritance

Answer 24

many phenotypes depend on several gene pairs at different locations acting in tandem; results in continuous (quantitative) phenotypic variation between 2 extremes; skin color, height, metabolic rate, intelligence = examples in humans

Question 25

Phenocopies

Answer 25

environmentally produced phenotypes that mimic conditions that may be caused by genetic mutations (permanent transmissible changes in the DNA); ex = thalidomide babies - developed phenotypes not directed by their genes

Question 26

Genomic imprinting

Answer 26

during gametogenesis, when certain genes in both sperm and eggs are modified by the addition of a methyl group; tags genes as paternal or maternal and confers important functional differences in the embryo

Question 27

Pedigree

Answer 27

traces a genetic trait through several generations and helps predict the future

Question 28

Amniocentesis

Answer 28

most common type of fetal testing

Question 29

Chorionic villus sampling (CVS)

Answer 29

procedure that suctions off bits of the chorionic villi from the placenta for examination