Genetics - Cells, Cell Cycle, Mitosis

What does DNA stand for?

deoxyribonucleic acid

How many chromosomes do humans have?

46

What proteins are DNA strands wrapped around to form a complex?

histones

Somatic cells

Cells that are not sex cells (normal amount of chromosomes; 46 in humans, 2n)

Autosomes

22 pairs of chromosomes that are not sex cells

What are the three things that genes do?

1. Code for protein (for structure and support and the production of enzymes and antibodies)
2. Help in the maintenance of the organism's cells
3. Control particular traits

Sex chromosomes

X and Y; has an influence over the sex of the offspring.

Alleles

Different variations of genes that control visible characteristics.

Stages of mitosis

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Interphase

Non-cell division; normal cell activity (metabolism, movement, gas exchange)

Phases of interphase

G1 - Growth 1 (rapid growth)
S - Synthesis (duplication of DNA in preparation for cell division)
G2 - Growth 2 (more growth)

Cytokinesis

Complete division of the rest of the cell (mitosis is only nucleic division)

What is the cell plate in cytokinesis (for plant cells)?

Cell plate is built by golgi-body vesicles

Homologous chromosomes

Similar chromosomes that carry genes for the same traits (same gene but different alleles)

Karyotype

An organized profile of a person's chromosomes

Three main purposes of cell division

1. Repairment (replacing dead/damaged cells)
2. Growth of an organism
3. Procreation (asexual reproduction to produce more alike cells)

Prophase

Chromatin condenses into chromosomes made up of two sister chromatids that are joined together by the centromere. Nuclear membrane begins dissolving, centrioles move to opposite poles of the cell and start producing spindle fibres.

Metaphase

Chromosomes align in the center of the cell, the nuclear envelope is completely dissolved, spindle fibres are visibly attached to the centromere of each of the chromosomes.

Anaphase

The spindle fibres contract and pull the sister chromatids apart, pulling them to opposite poles of the cell.

Telophase

New nuclear envelopes form around the two groups of daughter chromosomes, the chromosomes unravel and decondense into chromatin (small strands of DNA). Spindle fibre dissolves and is discarded. A cleavage furrow begins to form down the middle of the cell to prepare for cytokinesis.