heredity (test 3)

Question 1

gregor mendel

Answer 1

• austrian mathematican
• used pea plants to study heredity
• hand pollinated plants

Question 2

genotypes

Answer 2

• represents 2 alleles for 1 gene

Question 3

phenotypes

Answer 3

• physical appearance

Question 4

dominant allele

Answer 4

• always expressed

Question 5

recessive allele

Answer 5

• effect is masked if a dominant allele is present

Question 6

monohybrid cross

Answer 6

• heterozygous parents
• genotype ratio: 1:2:1
• phenotype ratio: 3:1

Question 7

dihybrid cross

Answer 7

• 2 genes on same chromosome
• phenotype ratio: 9:3:31

Question 8

codominance

Answer 8

• more than 1 allele encodes a functional protein
• blood types: IA and IB dominant, I gene can also have recessive i allele, which is nonfunctional if present

Question 9

x linked traits

Answer 9

• any genes on X chromosome are always expressed in males
• can be masked in females because they have 2 X’s
• ex: hemophilia, red-green colorblindness

Question 10

law of independent assortment

Answer 10

• the segregation of alleles for one gene does not influence the segregation of alleles for another gene.

Question 11

true breeding plant

Answer 11

• produce offspring identical to themselves

Question 12

hybrid plant

Answer 12

• resemble true breeders, produce mixed offspring

Question 13

x inactiviation

Answer 13

• female mammals have a double dose of every gene on X chromosome
• in early development, 1 X chromosome is shut off in each cell
• inactive X: barr body

Question 14

incomplete dominance

Answer 14

• heterozygote has an intermediate
  phenotype
• ex: dominant red+recessive white=heterozygous pink