Genome
Complete set of DNA within a cell
Haploid Cells
Contain one set (n) of chromosomes
- Seen in gametes, i.e. sperm or egg cells
Are non-homologous chromosomes
Diploid Cells
Contain two sets (2n) of
chromosomes
- Seen in body cells
Are homologous chromosomes (matched pairs)
Combination of Haploid & Diploid
Haploid gametes come together (the sperm & eggs during fertilization) and result in the creation of diploid cells in new individual
Genes
Are nucleotide segments of DNA
- Contains a code for making proteins
- 1 or more genes can affect the specializtaion and presentation of traits (ex : ear lobes)
- Traits can vary producing variation within species
The Cell Cycle
- Is a series of events within a cell
- Involves growth (Interphase) and
division (Mitosis) - Results in two daughter cells that are genetically identical to the parent
Interphase - G1 Phase (1st Phase)
- Gather E & P for DNA
Consists of gathering energy and proteins for making more DNA
- Checkpoint → checking for adequate energy/proteins & no damage to DNA
If something is wrong, checkpoints allows for the process to stop
Interphase - S Phase (2nd Phase)
- Synth & DNA rep causes 2 copies of chromo.
- Cent. duplicates
Synthesis occurs & DNA replication results in 2 copies of chromosomes (sister chromatids)
- Centrosome duplicates
Interphase - G2 Phase (3rd Phase)
- Store E & P
- O is duplicated
- Stores more energy and proteins
- Some organelles are duplicated
- Checkpoint → adequate energy/proteins & no damage to DNA
Mitosis
Consists of splitting the cell by dividing the nucleus and cytoplasm into two daughter cells that each contain the same number of chromosomes as their parent cell.
Involves 5 steps:
1. Prophase
2. Prometaphase
3. Metaphase
4. Anaphase
5. Telophase
Prophase
- Mem —> breaks
- Cent. —> migrate
- Mitotic S —> extends
- Membrane around nucleus breaks apart
- Centrosomes migrate to poles
- Mitotic spindle extends from centrosomes
Prometaphase
- MS —-> Develops
- Chrom. —> condense
- Mitotic spindle continues to develop
- Chromosomes continue to condense
Metaphase
- Chrome align
- Chrome condensed
- Chromosomes align along the metaphase plate
- Chromosomes are condensed
- Checkpoint a→ re sister chromatids
attached to mitotic spindle?
Anaphase
- SC –> split
- Chromatid –> pulled toward op poles
- Sister chromatids split at centromeres
- Each chromatid is pulled toward opposite ends (poles) of the cell
Telophase
- Chromatid unravel
- Nuclear M forms
- Each chromatid begins to unravel or decondense at their poles
- The nuclear membrane forms around the chromosomes
Cytokinesis
The separation into two daughter cells
- The separation occurs because of the cleavage furrow, the site along the equator that pulls inward and pinches together separating the cells
