Mitosis is the step during which the cell’s nucleus divides into two new nuclei. During mitosis, one copy of the DNA is distributed into each of the two daughter cells. Scientists divide mitosis into four parts (phases): prophase, metaphase, anaphase, and telophase. During prophase, the thread-like chromatin in the nucleus condenses to form double-rod structures called chromosomes. During metaphase, the chromosomes line up across the center of the cell.
Cell division stops until p53 binds to DNA and repairs the damage. C. p53 is an example of an oncogene, and its expression causes uncontrolled cell division. D. activation of p53 leads to inhibition of the S-phase cyclin-CDK complex. 6. All of the following statements correctly describe M-Cdk, EXCEPT: A. M-Cdk causes the cell to enter S phase and begin DNA replication.
Comparison chart | Meiosis | Mitosis | Definition: | A type of cellular reproduction in which the number of chromosomes are reduced by half through the separation of homologous chromosomes in a diploid cell. | A process of asexual reproductionin which the cell divides in two producing a replica, with an equal number of chromosomes in haploid cell | Function: | sexual reproduction | Cellular Reproduction & general growth and repair of the body | Type ofReproduction: | Sexual | Asexual | Occurs in: | Humans, animals, plants, fungi | all organisms | Genetically: | different | identical | Crossing Over: | Yes, mixing of chromosomes can occur. | No, crossing over cannot occur.
These sister chromatids are then separated in anaphase as the spindle microtubules attaches to centromere and pulls the sister chromatids to opposite poles. As the sister chromatids separate they are called chromosomes. This means that each pole has the same chromosomes (same genetic material). Finally the microtubules break down, the chromosomes uncoil and the nuclear membrane reforms. The cell then divides into two daughter cells with genetically identical
Which sex cells join together during fertilization is a random process. New combinations of genes occur, producing genetic variation 2. During meiosis, chromosome pairs sort themselves independently and randomly (this is called random segregation). This produces genetic variation also. 3.
RNA primase lays the beginning for DNA Primase to begin laying down the nucleobases: Adenine, Thymine, Cytosine and Guanine. 3. Okazaki fragment from RNA primase a segment of the lagging strand during replication. 4. DNA ligase goes over all the small Okazaki segments and binds them into a new strand of DNA.
Messenger RNA Seeks Steady Work Ad #1133 Student answers will vary but should include that RNA is transcribed when lactose is present. It is then that the repressor is released from the operator and no longer blocks the attachment of RNA polymerase to the promoter. This allows transcription to begin.
In the first mutation of the CYP2C9 gene described in Henry’s story, the 1075th nucleotide had changed from an adenine (A) to a cytosine (C). This mutation converts an ATT triplet code in the coding strand of the DNA molecule to CTT. Beginning with this triplet code on the DNA, describe the effect that this change would have on the following: a. The nucleotide sequence on the template strand of the gene. GAA b.
When a B cell reacts, it binds, engulfs and processes that antigen. Specificity, Diversity and Immunological memory are all parts of the Clonal Selection theory. Embryos contain many different lymphocytes, which are genetically programmed to recognize a particular antigen and make antibodies to destroy it. If the lymphocyte encounters and recognizes it after development is complete, it divides repeatedly to produce a clone. If during development it encounters its programmed antigen as part of a normal host substance, the lymphocyte is somehow destroyed.
B cell enters the germinal center and undergoes rapid division. Introduces mutations around VDJ gene. Each B cell expresses slightly diff antibody, one with greatest affinity will bind to antigen on dendritic cell. The rest will die via apoptosis. Interaction with T cell causes class switching of IgM on naïve B cell.