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Chromosomes are only present in the cell cycle during?
Chromosomes are present in the cell cycle during the S (synthesis) phase and the M (mitotic) phase. In the S phase, DNA is replicated to produce identical sister chromatids, while in the M phase, the chromosomes condense and align for segregation into daughter cells during cell division.
How many times does DNA replicate in meiosis?
1 time only which is done during the only interphase in meiosis.
What happens to the chromosomes during S-phase?
The S-phase is during interphase, which means there are no chromosomes. DNA is replicated in the S-phase ("s" for synthesis). It can only be replicated in the form of chromatin, not wrapped up in chromosomes.
How many times does DNA replicate in mitosis?
DNA replicates only once during the S phase of the cell cycle before mitosis begins. This ensures that each daughter cell receives a complete set of genetic material that is identical to the parent cell.
When does a human cell normally contain 92 chromosomes?
Human cells NEVER normally contain 92 chromosomes. A diploid human cell prior to replicating its DNA has 23 pairs of non-replicated chromosomes (46 total). A diploid human cell after replicating its DNA has 23 pairs of replicated chromosomes (46 total). The difference is that each replicated chromosome consists of two DNA molecules called 'sister chromatids'. Non-replicated chromosomes consist of only one DNA molecule (it is not called a chromatid because chromatids are like twins--if you only have one you don't say there is one twin. Thus, you can say that a human cell following DNA replication has 92 chromatids, but never 92 chromosomes. ---------------edit-------------- Actually, there is a certain period in Mitosis of the cell cycle where you will temporarily have 92 chromosomes - during Anaphase and Telophase ( Mitosis consists of 4 phases occurring in the following order: Prophase, Metaphase, Anaphase, Telophase). As explained above, 46 sister chromatids are produced after DNA replication (which occurs in synthesis phase of the cell cycle). During Anaphase, the 46 sister chromatids separate, resulting in 92 chromosomes, or 2 sets of 46 chromosomes. Each set then travels to opposite ends of the cell. Next, during Telophase, the cell then elongates and the nuclear envelope forms around each set to form two nuclei. Then next in Cytokinesis, the cell actually slits into two cells, each with one nucleus holding 46 chromosomes.
Chromosomes are only present in the cell cycle during?
Chromosomes are present in the cell cycle during the S (synthesis) phase and the M (mitotic) phase. In the S phase, DNA is replicated to produce identical sister chromatids, while in the M phase, the chromosomes condense and align for segregation into daughter cells during cell division.
When do the mitochondria replicate in the cell cycle?
In most eukaryotes mitochondria replicate and fuse all the time; they don't have to replicate during the cell cycle. In cells that have only one mitochondrion (like kinetoplastids) mitochondria follow the same replication process as the cells (G1, S, G2 and M phases).
How many times does DNA replicate in meiosis?
1 time only which is done during the only interphase in meiosis.
When examining cells in the laboratory you notice that a particular cell has half as much DNA as the surrounding cells. This observation can be explained if this cell's cell cycle halted at checkpoint?
This observation likely indicates that the cell is in the G1 phase of interphase, having not yet replicated its DNA, while the surrounding cells have completed DNA synthesis during the S phase. If the cell's cycle halted at the G1 checkpoint, it would not proceed to S phase, resulting in only half the amount of DNA compared to its neighbors. This could be due to factors such as DNA damage or insufficient growth signals that prevent the cell from progressing in the cycle.
What are internal regulate?
Internal Regulators Proteins that respond to events inside the cell are called internal regulators. Internal regulators allow the cell cycle to proceed only when certain processes have happened inside the cell. For example, several regulatory proteins make sure that a cell does not enter mitosis until all its chromosomes have been replicated. Another regulatory protein prevents a cell from entering anaphase until all its chromosomes are attached to the mitotic spindle. Internal Regulators Proteins that respond to events inside the cell are called internal regulators. Internal regulators allow the cell cycle to proceed only when certain processes have happened inside the cell. For example, several regulatory proteins make sure that a cell does not enter mitosis until all its chromosomes have been replicated. Another regulatory protein prevents a cell from entering anaphase until all its chromosomes are attached to the mitotic spindle. Internal regulators are proteins that respond to activity within a cell.
What directs cell growth and reproduction?
Cell growth and reproduction are directed by the cell cycle, a series of events that lead to cell division. Key regulators of the cell cycle include checkpoints that monitor DNA integrity, external signals from the environment, and cyclin-dependent kinases that control progression through different phases of the cell cycle. These regulators ensure that cells only divide when conditions are favorable and that DNA is accurately replicated and distributed to daughter cells.
What happens to the chromosomes during S-phase?
The S-phase is during interphase, which means there are no chromosomes. DNA is replicated in the S-phase ("s" for synthesis). It can only be replicated in the form of chromatin, not wrapped up in chromosomes.
How lytic cycle is more efficient?
The only thing the lytic cycle is more efficient in is killing the cell. The lytic cycle is when the initiation of making lots of bacteria copies begin. Once complete, the cell bursts and the virus products will scatter and infect other cells.
What is the relationship between skin cancer and cell cycle?
skin cancer (any cancer for that matter) is when the cell cycle becomes completely unregulated and only performs cell division without its normal cell functions.
Is it true mutations can only occur during interphase?
Mutations can occur at any time during the cell cycle, but they are most commonly associated with interphase when DNA is being replicated. During DNA replication in the S phase of interphase, errors can happen, leading to mutations. Additionally, exposure to mutagens or DNA damage can cause mutations during other phases of the cell cycle, including mitosis. Therefore, while interphase is a key time for mutations, it is not the only phase where they can occur.
Proteins that regulate the cell cycle based on events inside the cell are called?
Checkpoint proteins. These proteins monitor the various stages of the cell cycle and ensure that the cell progresses to the next stage only if certain conditions are met. They play a crucial role in maintaining the integrity of the cell cycle and preventing uncontrolled cell division.
How many days between women realising each egg cell during menstrual cycle?
A female will only ovulate once per menstrual cycle, typically this occurs 12-16 days before menstruation. During the 24 hours of ovulation it is possible to release multiple eggs, but most commonly only one egg is released per cycle.
