Chapter 11Cell Reproduction By Andrey Mychajlyszyn
The Cell Cycle
This is the series of events that occur in a cell when it is leading up to its division and duplication of its DNA to produce two daughter cells from the mother cell. Once the cells are divided, they are the same size and shape. In the cell, the cytoplasm divides.
This is the phase of the cell cycle in which a cell spends most of its life. During interphase, a cell copies its DNA so it can prepare for mitosis which is when a cell divides to form two new identical cells. This phase consists of three stages which are the G1, S, and G2. The G1 stage helps out with metabolic activities such as cell growth, the S stage is responsible for DNA synthesis meaning that a cell needs to double its DNA to later get two new identical cells after mitosis, and the G2 stage enables protein synthesis needed for cell division. The G2 stage needs to pass through checkpoints so multiplication by division could occur.
Shows the stages of Interphase
This is the first stage of mitosis and happens when a cell's chromosomes have condensed. If the cell has centrosomes, one of them moves to the opposite side of the cell. As a result of the movement of one centrosomes, microtubules begin to assemble and lengthen from the centrosomes and therefore form a "spindle", which is a temporary structure for moving chromosomes during nuclear division. The spindles penetrate the nuclear region as the nuclear envelope breaks up. When prophase ends, one sister chromatid of each chromosome has become attached to microtubules extending from one spindle pole, and the other sister chromatid has become attached to microtubules extending from the other spindle pole. The opposing microtubules then push and pull the chromosomes, which eve tally causes the chromosomes to be aligned midway between spindle poles.
This is one of the final stages of mitosis. This stage occurs when all the microtubules are the same length, therefore making the chromosomes aligned midway between spindle poles. The chromosomes that are aligned are still duplicated and they are at their second-most condensed and coiled stage.
During this stage, the spindle pulls the sister chromatids of each chromosome that is duplicated apart and moved them toward opposite spindle pores. This in turn causes each DNA molecule to now become a separate chromosome. Also in this stage, the chromosomes are the most condensed and coiled up to help with the reformation of the nucleus.
This is the final stage of mitosis. It begins when two clusters of chromosomes reach the spindle poles. Each cluster has the same number and kinds of chromosomes as the nucleus of the parent cell had. After, a new nuclear envelope forms around each set of chromosomes as they loosen. The chromosomes arrive at the opposite spindle pores and decondense, and two new nuclei form.
These are noncoding, repetitive DNA sequences that occur at the ends of eukaryotic chromosomes. They protect the coding sequences from degradation and from losing genetic informational their ends. They shorten with every cell division in normal body cells. However, when they are too short, the cell stops dividing and therefore dies. As a result of this process, telomeres are associated with aging.
This is a disease that occurs when the abnormally dividing cells of a malignant neoplasm (an accumulation of diving cells) disrupt body tissues, both physically and metabolically. The abnormal cell growth has the potential to invade or spread to other parts of the human body. The only way to elimate mailgant cells from the body, chemotherapy or other surgical procedures need to be done.