Genetics Concept Check Answers

Concept Check 10.1

  1. Particulate hypothesis – parents pass on distinct factors that retain their identity

Blending hypothesis – parents genetic material blends in the offspring

  1. Self-fertilization: sperm fertilizes egg of same plant

Cross-fertilization: sperm from one flower fertilizes egg of different plant

  1. For example, red flower plants can produce yellow offspring

Concept Check 10.2

  1. A or a. Each a 50% chance.
  1. 25% AA, 50% Aa, 25% aa

AA / Aa
Aa / aa
  1. PPRR, PpRr, PPRr, PpRR
  1. PW, Pw, pW, pw

Concept Check 10.3

  1. 1 : 2 : 1. Should be 3:1 in a simple dominant-recessive cross
  1. Type O
  1. Polygenic inheritance. Potential combinations of the alleles increase with the number of genes affecting a character.
  1. Height, build, shade of skin, or blood count

Concept Check 10.4

  1. R on one and Y on the other. R on one and y on the other.
  1. Alleles that are farther apart are more likely to recombine from crossing over in meiosis.

Concept Check 10.5

  1. Males require only one recessive trait in the X chromosome. Females must have recessive on both.
  1. No. The son must get a Y chromosome from the father, which does not carry the allele.

Concept Check 12.2

  1. Person who has trisomy 21 demonstrates Down syndrome. During meiosis the gamete could fail to separate chromosomes, adding an additional chromosome.
  1. See vocabulary: deletion, duplication, inversion, translocation
  1. Genes that move to different sections of a chromosome or different chromosomes – disrupting other genes.
  1. Increase in age increases chance of nondisjunction during meiosis

Concept Check 12.3

  1. Sex of each member of extended family, relations by birth and marriage, which individuals show the trait.
  1. Recessive- albinism, Dominant- Huntingtons, Sex-linked- colorblindness or hemophilia. Recessive- both recessive present; Dominant one allele present; X-linked- present on one X of male or both X on female.
  1. Examine couple’s family history, interpret genetic results, helps couples determine risk of passing trait on to children.