Question

what do the letters on the outside of a punnett square represent?
offspring body cells
offspring gametes
parental body cells
parental gametes
question 11
what do the 2 - letter combinations inside each of the four squares in a punnett square represent?
offspring body cells
offspring gametes
parental body cells
parental gametes
question 12
in kangaroos, having 1 pouch (k) is dominant to having 2 pouches (k). what set of parents would result in 50% of the offspring having 1 pouch, and 50% having 2 pouches?
kk × kk
kk × kk
kk × kk
kk × kk
kk × kk
kk × kk

Explanation:

Question 10 (What do the letters on the outside of a Punnett square represent?)

A Punnett square is used to predict offspring genotypes. The letters outside (on the top and left) represent the alleles in the gametes produced by each parent. Gametes are sex cells (sperm/egg) with half the genetic material. Body cells are diploid (full set), gametes are haploid. Offspring body cells are the result of fertilization (inside the square), and offspring gametes are not represented on the outside. So the outside letters are parental gametes.

Inside the Punnett square, the 2 - letter combinations are formed by the fusion of parental gametes during fertilization. These combinations represent the possible genotypes of the offspring's body cells (since offspring body cells are diploid, with one allele from each parent). Parental gametes are outside, offspring gametes are not the focus here, and parental body cells are diploid but not what's inside the square. So they represent offspring body cells.

Step 1: Recall Dominance and Punnett Squares

K is dominant (1 pouch), k is recessive (2 pouches). Offspring with 2 pouches must have genotype kk (since k is recessive, so both alleles must be k). For 50% kk and 50% with K_ (1 pouch), we need to find parental cross.

Step 2: Analyze Each Cross

• KK × kk: All offspring are Kk (1 pouch), so 100% 1 pouch. Eliminate.
• KK × Kk: Offspring genotypes: KK, Kk (all 1 pouch). Eliminate.
• KK × KK: All KK (1 pouch). Eliminate.
• Kk × kk: Gametes from Kk: K, k; from kk: k, k. Punnett square:

	k	k
k	kk	kk

Offspring: 50% Kk (1 pouch), 50% kk (2 pouches). This matches.

• kk × kk: All kk (2 pouches). Eliminate.
• Kk × Kk: Offspring: 25% KK, 50% Kk, 25% kk (75% 1 pouch, 25% 2 pouches). Eliminate.

Answer:

Parental gametes

Question 11 (What do the 2 - letter combinations inside each of the four squares in a Punnett square represent?)