Question

practice: haploid v. 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 a visual arrangement of an organism's chromosomes, organized by size, shape, and number, used to analyze chromosomal abnormalities and determine sex.
2. In human karyotypes, autosomes are non-sex chromosomes. There are 22 pairs (44 total) of autosomes, and 2 sex chromosomes (1 pair).
3. The last pair is the sex chromosomes. This karyotype has two X chromosomes (XX), which is the typical sex chromosome complement for a female human.
4. A diploid cell has two sets of chromosomes (one from each parent). This karyotype shows pairs of each chromosome, so it is diploid.
5. Diploid chromosome counts are found in somatic (body) cells of humans, such as skin, liver, and muscle cells.
6. Each chromosome here consists of two sister chromatids, which is the state of chromosomes after DNA replication in the S phase of interphase (before cell division).
7. Meiosis reduces the chromosome number by half, resulting in haploid cells. The post-meiosis karyotype would have only one copy of each chromosome (22 autosomes + 1 sex chromosome, for a total of 23 chromosomes, no pairs).

Answer:

1. A visual arrangement of an organism's chromosomes, sorted by size, shape, and number, used for genetic analysis.
2. 44 autosomes; 2 sex chromosomes
3. Female. The last pair is XX, which is the sex chromosome combination for human females.
4. Diploid. The karyotype shows two copies (a homologous pair) of each chromosome.
5. Somatic (body) cells (e.g., skin, muscle, liver cells)
6. After DNA replication. Each chromosome has two attached sister chromatids, which forms after DNA is copied in S phase.
7. It would have 23 total chromosomes, with only one single copy (no homologous pairs) of each autosome and one sex chromosome (either X), resulting in a haploid set.