Question

n, an egg and a sperm cell each have __ chromosomes that a zygote has __ chromosomes.
select the center of each box in the punnett square until it shows the correct genotype (yy, yy, or yy) for pea color.
not quite. please try again!
check

Explanation:

First Part (Chromosome Numbers)

Step1: Recall gamete chromosome number

Gametes (egg, sperm) are haploid. In humans, gametes have 23 chromosomes (general knowledge for diploid organisms: gametes have half the number of chromosomes of somatic cells). For a typical diploid organism, if somatic cells have \(2n\) chromosomes, gametes have \(n\).

Step2: Recall zygote chromosome number

A zygote is formed by the fusion of an egg and a sperm, so it is diploid. So it has \(2n\) chromosomes (same as somatic cells). For humans, zygote has 46 chromosomes (since gametes have 23, \(23 + 23=46\)).

Step1: Top - left box

Combine top - left gamete (\(Y\)) and left - side gamete (\(Y\)): Genotype is \(YY\) (correct as shown? Wait, no, wait the given Punnett square has some errors? Wait, no, let's re - check. Wait, the side column is \(Y\) and \(y\), top row is \(Y\) and \(Y\).

Top - left box: \(Y\) (top) and \(Y\) (side) → \(YY\) (correct as in the box? The box has \(YY\), that's correct.

Top - right box: \(Y\) (top) and \(y\) (side) → \(Yy\) (the box has \(Yy\), correct).

Bottom - left box: \(Y\) (top) and \(Y\) (side) → \(YY\) (the box has \(YY\), correct).

Bottom - right box: \(Y\) (top) and \(y\) (side) → \(Yy\) (the box has \(Yy\), correct). Wait, but the "Not quite" message suggests a mistake. Wait, maybe the parent's genotypes are different. Wait, maybe one parent is \(Yy\) and the other is \(Yy\)? Wait, no, the top row is \(Y\), \(Y\) and side is \(Y\), \(y\). Wait, maybe the correct way: if the top parent is \(YY\) (homozygous dominant) and the side parent is \(Yy\) (heterozygous), then:

• Top - left: \(Y\times Y = YY\) (correct)
• Top - right: \(Y\times y = Yy\) (correct)
• Bottom - left: \(Y\times Y = YY\) (correct)
• Bottom - right: \(Y\times y = Yy\) (correct)

Wait, but the "Not quite" message implies that the current genotypes are wrong. Wait, maybe the parent's genotypes are \(Yy\) and \(Yy\). Let's try that. If both parents are \(Yy\) (gametes \(Y\) and \(y\) for both).

Then:

• Top - left: \(Y\times Y = YY\)
• Top - right: \(Y\times y = Yy\)
• Bottom - left: \(y\times Y = Yy\)
• Bottom - right: \(y\times y = yy\)

Ah! So the mistake in the given Punnett square is the bottom - left and bottom - right? Wait, no, the given Punnett square has bottom - left as \(YY\) and bottom - right as \(Yy\), which is wrong if both parents are \(Yy\). Wait, maybe the top parent is \(YY\) and the side parent is \(yy\)? No, side parent has \(Y\) and \(y\).

Wait, let's start over. The Punnett square is used to predict the genotypes of offspring by combining the alleles of the parents. Each box in the Punnett square is formed by taking one allele from the top row (parent 1's gametes) and one allele from the side column (parent 2's gametes).

If parent 1 (top row) has alleles \(Y\) and \(Y\) (so gametes are \(Y\) and \(Y\)) and parent 2 (side column) has alleles \(Y\) and \(y\) (gametes are \(Y\) and \(y\)):

• Box 1 (top - left): \(Y\) (parent 1) and \(Y\) (parent 2) → \(YY\)
• Box 2 (top - right): \(Y\) (parent 1) and \(y\) (parent 2) → \(Yy\)
• Box 3 (bottom - left): \(Y\) (parent 1) and \(Y\) (parent 2) → \(YY\)
• Box 4 (bottom - right): \(Y\) (parent 1) and \(y\) (parent 2) → \(Yy\)

But if parent 2 is \(Yy\) (gametes \(Y\) and \(y\)) and parent 1 is \(Yy\) (gametes \(Y\) and \(y\)):

• Box 1: \(Y\times Y = YY\)
• Box 2: \(Y\times y = Yy\)
• Box 3: \(y\times Y = Yy\)
• Box 4: \(y\times y = yy\)

So the correct genotypes depend on the parents' genotypes. Assuming the parents are \(Yy\) (both), the correct Punnett square should be:

	\(Y\)	\(y\)
\(y\)	\(Yy\)	\(yy\)

So in the given Punnett square, the bottom - left box (which is \(YY\) in the given) should be \(Yy\), and the bottom - right box (which is \(Yy\) in the given) should be \(yy\) if parents are \(Yy\times Yy\).

Answer:

(For a typical diploid organism like human): An egg and a sperm cell each have \(n\) (e.g., 23 in human) chromosomes; a zygote has \(2n\) (e.g., 46 in human) chromosomes.

Second Part (Punnett Square Genotypes)

To determine the correct genotypes in the Punnett square, we use the principle of combining alleles from the parents. Let's assume the parents' genotypes: one parent has alleles \(Y\) and \(Y\) (top row, so gametes are \(Y\) and \(Y\)) and the other parent has alleles \(Y\) and \(y\) (side column, gametes are \(Y\) and \(y\)).