Question

1. which healthy gamete could not result from the parent cell shown?

a
b
c
d
gamete a
gamete b
gamete c
gamete d

Explanation:

Step1: Understand Gamete Formation

Gametes are formed through meiosis. Each gamete should have one copy of each type of chromosome (in terms of color and size as per the parent cell).

Step2: Analyze Each Gamete

- **Gamete A**: Has one green (long) and one light - blue (short) chromosome. This is a valid combination.
- **Gamete B**: Has one green (long) and one dark - blue (short) chromosome. Since the parent cell has dark - blue and light - blue (different short - sized chromosomes), this is not a valid combination as the parent cell does not have a "dark - blue" short - sized chromosome in the original set (the short - sized chromosomes in the parent are light - blue and the long - sized are green and dark - green).
- **Gamete C**: Has one light - blue (short) and one dark - blue (long, but after meiosis, size - wise it can be considered as a valid segregation if we assume correct splitting). Wait, no, actually looking at the parent cell, there are two long (green and dark - green) and two short (light - blue and another). But in meiosis, each gamete gets one of each "pair" (in terms of homologous chromosomes). If we consider the short ones: one light - blue and one (let's assume the other short is a different entity, but in the options, Gamete C has two short - like (but in reality, after meiosis, if we assume proper segregation of homologous pairs. Wait, re - evaluating. The parent cell has four chromosomes: two long (green and dark - green) and two short (light - blue and another). When forming gametes (which are haploid), each gamete should get one long - equivalent (after meiosis, the sister chromatids separate, but in terms of the original homologs) and one short - equivalent. Wait, no, actually in meiosis I, homologous chromosomes separate. If we assume the two long chromosomes are homologs (green and dark - green) and the two short chromosomes are homologs (light - blue and another color, say purple - but in the options, Gamete C has light - blue (short) and dark - blue (but dark - blue was a long in parent? No, no, looking at the original parent cell: top - left is dark - blue (long), bottom - left is green (long), top - right is green (long), bottom - right is light - blue (short). Wait, no, actually, in the parent cell (diploid), there are two pairs of homologous chromosomes. Let's assume the long chromosomes: one dark - blue and one green (homologs). The short chromosomes: one light - blue and one (maybe the other color in the options, but in Gamete C, if we consider that after meiosis I (homologous separation) and meiosis II (sister - chromatid separation), Gamete C has light - blue (from the short homolog pair) and dark - blue (from the long homolog pair. Wait, no, no! Wait, each gamete should have one chromosome from each homologous pair. The parent cell has two homologous pairs: long (dark - blue and green) and short (light - blue and another). Gamete B has a green (long - homolog) and a dark - blue (but dark - blue was a long - homolog. So Gamete B is taking two from the long - homolog pair (which is wrong. Wait, no, no! Wait, in the parent cell, the chromosomes are in pairs. Let's re - define: assume there are two homologous pairs. Pair 1: long chromosomes (dark - blue and green). Pair 2: short chromosomes (light - blue and another). When forming gametes (haploid), each gamete must have one from pair 1 and one from pair 2. Gamete A: green (pair1) and light - blue (pair2) - valid. Gamete B: green (pair1) and dark - blue (but dark - blue is also pair1) - invalid. Gamete C: light - blue (pair2) and dark - blue (pair1) - valid. Gamete D: dark - blue (pair1) and green (pair1? No, wait no, no, after meiosis, sister chromatids separate. Wait, no, in meiosis I, homologous chromosomes (one from each parent) separate. So if pair1 is dark - blue (from one parent) and green (from another parent) for long chromosomes, pair2 is light - blue (from one parent) and another (say purple) for short. Each gamete gets one long (either dark - blue or green) and one short (either light - blue or purple). Gamete B is taking green (long) and dark - blue (long) - two long (violating the haploid requirement of one long and one short).

Answer:

Gamete B