Genetics – Compendium 2

Table of Content

Chromosomes
Cell Cycle
Mitosis
DNA’s role during Mitosis
Gene expression
Cancer Cells
Genetic traits and Meiosis
Alleles

Chromosomes

- Chromosomes which are contain inside of the cell nucleus.
- The human nucleus contains 23 pairs of chromosomes. Totaling 46 chromosomes.
- 22 of these pairs are known as autosomes, which carry genes traits having nothing to do with sex of the individual.
- 1 pair contain genes that determine individual sex
- Males have the pair of X and Y
- Female has the pair of X chromosomes

Cell Cycle

- Two cycles of the cell occur continuously
- Interphase, during which normal cell function is happening.
- Interphase is also when the cell prepare for division, lasting about 20 hours or 90% of the cell cycle.
- Cell division has two stages
- Mitosis, nuclear division with two identical sets of chromosomes.
- Cytokinesis, division of cytoplasm

Mitosis

-Duplication division assures that cell chromosomes are in the same amount and kind.
- Phases of Mitosis
- Prophase, Chromosomes attach to spindle fibers.
- Metaphase, Chromosomes align at the equator
- Anaphase, Chromatids separate, and now chromosomes move towards poles.
-Telophase, Nucleus develops around chromosomes, cytokinesis begins.
- Mitosis is critical for growth and tissue repair.

DNA’s role during Mitosis

- DNA is replicate and passed on to daughter cells
- DNA information from parent cells is transcribed into protein that will run daughter cells metabolism.
- DNA is a double helix that can separate and transcribe to other half mRNA.
- mRNA then translates into amino acids that fold up to build proteins.
- Ribosome’s translate mRNA and make proteins
- These proteins effect and cause cell metabolism.

Gene expression

- Gene expression is regulated
- Cell feed back is how regulations controls metabolism
- Lack of cell regulation caused problems with gene expression.
- Cancer can be the outcome.

Cancer Cells

- Characteristics
- Abnormal size nuclei
- Abnormal amount of chromosomes
- Abnormal amount of chromosomes allows cell to divide repeatedly and continue doing so.
- Cancer cells can form tumor
- Cancer cells aren’t encapsulate and can spread to surrounding tissues
- Cancer can be caused by genetics heredity, environmental, carcinogens, and poor diet.
- Cancer is a genetic disease.

Genetic traits and Meiosis

- During meiosis gametes are formed having all possible combinations of parent chromosomes.
- During fertilization complete chromosome recombination occurs and mitosis can begin with a full set of 23 pair chromosomes.

Alleles

-During meiosis small variations in the DNA and chromosomes protein coding cause Alleles.
- Hereditary traits for the mother or father are passing to the zygote by the combination of these Alleles at particular gene or chromosome regions.
- These sometime dominate traits give us an advantage in survival.
- With this advantage or disadvantage, the basis of evolution’s natural selection.