emmajohnson's version from 2015-04-29 17:58


Question Answer
Describe how DNA and genes are stored in the nucleus of the cell.DNA is stored by tightly winding around itself and some specialized proteins. The resulting structure is called a "chromosome", which is found in the nucleus of the cell.
Describe the parts of a chromosome.Sister Chromatids - two identical copies of the chromosome. During cell division all the DNA of each chromosome is replicated. They eventually separate to become a full chromosome.
Centromere - the central region of the chromosomal structure. It's where the two sister chromatids are joined to each other.
DNA - Each chromosome contains a long linear molecule of DNA and there's more than two metres of it in each one. So for it to be able to fit it's tightly wound around histone proteins.
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Telomeres - repetitive DNA sequences that are situated at the tips of chromosomes (the repeated sequence reads - TTAGGG). Telomeres protect the ends of the chromosomes from damage and stop them from becoming attached to each other. They shrink after every cell division. Compare and contrast homologous chromosomes and sister chromatids.A couple of homologous chromosomes are a set of one maternal chromosome and one paternal Homologous chromosomes are chromosome that pair up with each other inside a cell during meiosis. These copies have the same genes in the same locations, or loci. A sister chromatid refers to either of the two identical copies (chromatids) formed by the replication of a single chromosome, with both copies joined together by a common centromere. In other words, a sister chromatid may also be said as 'one-half' of the duplicated chromosome. Compare and contrast how mitosis is used by single-celled and multicellular organisms.In unicellular organisms such as bacteria, mitosis is a type of asexual reproduction, making identical copies of a single cell. In multicellular organisms, mitosis produces more cells for growth and repair. List the phases of the cell cycle and describe briefly what happens in each.In mitosis interphase which includes G1, S, G2, mitosis which includes PMAT, then cytokinesis. List the phases of mitosis and briefly describe the events of each phase.prophase-chromosome duplication,
metaphase-individual chromosomes line up at metaphase plate,
anaphase-sister chromatids separate,
telephase-daughter cells of mitosis 2n and 2n Describe the roles of centrioles and microtubules in cell division.
A centriole is a small set of microtubules arranged in a specific way. There are nine groups of microtubules. When two centrioles are found next to each other, they are usually at right angles. The centrioles are found in pairs and move towards the poles (opposite ends) of the nucleus when it is time for cell division.
Microtubules are filamentous intracellular structures that are responsible for various kinds of movements in all eukaryotic cells. Microtubules are involved in nucleic and cell division, organization of intracellular structure, and intracellular transport, as well as ciliary and flagellar motility. Compare and contrast cytokinesis in animal cells & plant cells.Plant cells form a cell plate (cellulose) that separates the two new cells. Vesicles containing building materials fuse with one another to form the disklike cell plate between the two new cells. In animal cells, a cleavage furrow on the outer surface indicates that two new cells are forming.
Contractile microfilaments pull the plasma membrane inward. Describe the genetic make up of cells produced by the process of mitosis.produces two exact copies of the original cell. This means that each daughter cell will have the same number of chromosomes, the same genetic code and, ultimately, the same function and characteristics as the original cell. Mitosis occurs in non-sex cells, since sex cells, such as eggs and sperm, must have only half the genetic material of the original cell. Sex cells are made through a different form of cell division called meiosis. Compare and contrast oncogenes and tumor suppressor genes.An oncogene is a gene that has the potential to cause cancer. In tumor cells, they are often mutated or expressed at high levels. Most of the normal cells will undergo a programmed form of rapid cell death (apoptosis) when critical functions are altered.
A tumor suppressor gene, or antioncogene, is a gene that protects a cell from one step on the path to cancer. When this gene mutates to cause a loss or reduction in its function, the cell can progress to cancer, usually in combination with other genetic changes. Define cancer, benign tumor, malignant tumor and metastasis.Metastasis, or metastatic disease, is the spread of a cancer or disease from one organ or part to another not directly connected with it. The new occurrences of disease thus generated are referred to as metastases