Question

1. in what phase do most cells spend the majority of their lifetime?
2. how often do human skin cells divide each day?
3. how many hours per day is a human skin cell in interphase?
4. what type of cell may spend decades in interphase instead of dividing?
5. name the 3 stages in interphase.

the cell cycle
mitosis (karyokinesis) - nuclear division
mitosis is the process in which a eukaryotic cell (cell containing a nucleus) separates its already duplicated chromosomes (copied during the s phase) into two sets of chromosomes so there will be two identical nuclei. it is generally followed by cytokinesis which divides the cytoplasm and cell membrane. color the cytokinesis stage yellow. this results in two identical cells (both have an identical set of chromosomes) with an equal distribution of organelles and other cellular components. the mitotic (m) phase and cytokinesis (c phase) together are called cell division, the division of the parent cell (original) into two daughter cells (new cells), each with the same genetic information (chromosomes) as the parent cell. mitosis does not occur in prokaryotic cells that do not have a nucleus. in multicellular organisms, the somatic cells (body cells) undergo mitosis, while germ cells - cells destined to become sperm in males or ova (eggs) in females - divide by a related process called meiosis. prokaryotic cells (bacteria), which lack a nucleus, divide by a process called binary fission.

1. when are chromosomes duplicated --- before or during mitosis?
2. what process follows mitosis?
3. the nucleus is divided during __________, while cytoplasm of the cell is divided during __________.
4. how do the two new cells compare with each other?
5. the two new cells are called ____________ cells.
6. does mitosis occur in prokaryotes? explain why or why not.
7. what process is used by bacteria to divide and reproduce?
8. body cells are called __________ cells, while reproductive cells are known as __________ cells.

Explanation:

1. Cells spend most of their lifetime in interphase. This is the stage where they grow, replicate DNA, and prepare for division.
2. Human skin cells divide about once a day. Skin cells need to constantly replace old or damaged cells.
3. A human skin cell is in interphase for about 22 hours per day. Interphase is the longest part of the cell cycle.
4. Nerve cells may spend decades in interphase instead of dividing. Once they are fully developed, they often do not divide.
5. The three stages in interphase are G1 (growth 1), S (synthesis - DNA replication), and G2 (growth 2).
6. Chromosomes are duplicated before mitosis, during the S phase of interphase.
7. Cytokinesis follows mitosis. It divides the cytoplasm and cell membrane.
8. The nucleus is divided during mitosis, while the cytoplasm of the cell is divided during cytokinesis.
9. The two new cells are identical to each other. They have the same set of chromosomes and genetic information.
10. The two new cells are called daughter cells.
11. Mitosis does not occur in prokaryotes. Prokaryotes do not have a nucleus, and mitosis is a process for eukaryotic cells with nuclei.
12. Bacteria use binary fission to divide and reproduce.
13. Body cells are called somatic cells, while reproductive cells are known as germ cells.

Answer:

1. Interphase
2. About once a day
3. About 22 hours
4. Nerve cells
5. G1, S, G2
6. Before mitosis
7. Cytokinesis
8. Mitosis; cytokinesis
9. They are identical
10. Daughter
11. No. Prokaryotes lack a nucleus, and mitosis is for eukaryotic cells with nuclei.
12. Binary fission
13. Somatic; germ