Question

practice: haploid vs. diploid
answer the following questions about the karyotype below:

1. what is a karyotype?
2. how many autosomes are in this human karyotype? how many sex chromosomes?
3. if the last pair reflects whether the organism is male or female, which would this organism be? explain how you know.
4. based on the picture, is this a karyotype of a diploid or haploid cell? explain how you know.
5. based on your answer to #4, what type of cells would have this amount of chromosomes in them?
6. is this a picture of chromosomes before or after dna replication during the s phase of interphase? explain how you know.
7. what would a karyotype like this look like after meiosis?

Explanation:

1. A karyotype is an organized profile (or picture) of a cell's chromosomes, arranged by size, shape, and number.
2. In a human karyotype, there are 44 autosomes (22 pairs) and 2 sex chromosomes.
3. If the last pair (sex chromosomes) are XX, it's female; if XY, male. From the image (assuming the last pair is XX or XY—if the last pair looks like two similar chromosomes, likely female (XX); if one is different (XY), male. Need to check the karyotype image: if the last pair has two identical - looking chromosomes, female (XX); if one is shorter (Y), male (XY).
4. Diploid cells have two sets of chromosomes (homologous pairs), haploid has one. A human karyotype with paired chromosomes (like the image shows pairs) is diploid, as diploid cells (somatic cells) have 2n chromosomes (paired), haploid (gametes) have n (unpaired).
5. If it's diploid (from #4), these are somatic cells (body cells like skin, liver, etc.), as gametes are haploid.
6. After DNA replication (S phase), chromosomes have sister chromatids (look like X - shaped). Before replication, they are single - stranded. If the chromosomes in the image have sister chromatids (each chromosome has two parts), it's after replication; if single, before.
7. After meiosis, the karyotype would be haploid: each cell would have 23 chromosomes (22 autosomes + 1 sex chromosome), unpaired (no homologous pairs), as meiosis reduces the chromosome number by half (from diploid 2n to haploid n).

Answer:

s:

1. An organized profile (picture) of a cell’s chromosomes, arranged by size, shape, and number.
2. 44 autosomes, 2 sex chromosomes.
3. (Depends on the last pair: if XX → Female (two identical sex chromosomes); if XY → Male (one X, one Y). Example: If last pair is XX, female, because female humans have two X chromosomes as sex chromosomes.)
4. Diploid. Because there are homologous chromosome pairs (each chromosome has a matching pair), characteristic of diploid (2n) cells.
5. Somatic cells (body cells, e.g., skin, muscle, liver cells), as they are diploid (2n), while gametes are haploid (n).
6. After DNA replication. Because the chromosomes appear to have sister chromatids (each chromosome has two chromatids), which form during S - phase replication.
7. After meiosis, the karyotype would be haploid: 23 chromosomes (22 autosomes + 1 sex chromosome), with no homologous pairs (each chromosome is single, not paired), representing the chromosome content of gametes (sperm or egg cells).