Lesson 4 – Genetics for Science 10 Cell Cycle & Mitosis Lesson 4 – Genetics for Science 10

Cell Cycle describes the life of a cell from the time it is first formed from a dividing parent cell until its own division into two cells! Key Terms of Genetic Material: Genome: all the genes of an organism Chromatin: thread-like structure composed of DNA and protein Chromosomes: tightly wound packages of chromatin (ready for cell division) In your nucleus, you have 2 sets of chromosomes: 23 pairs of chromosomes (46 individual chromosomes) -1 from dad, the other from mom Because you have 2 complete sets of chromosomes, you are diploid (2n); where n = 23 (number of pairs)

BLIND KAHOOT Kahoot is often used as a review, today we are going to use it to learn. Follow along with the handout

Chromatids: one of two distinct strands that make up a chromosome Centromere: holds together each pair of chromatids Somatic Cells: body cells (diploid) Gametes: sex cells (haploid) e.g. sperm and eggs

Why must cells divide? All cells must divide when they get too large! The surface area to volume ratio becomes too large that the cell can no longer function properly. Why? Surface allows nutrients in and waste out, not enough surface means can’t support the needs of the volume Before the nucleus can divide, it needs to make a duplicate copy of DNA

The Cell Cycle Two Parts: Interphase and Division

Interphase INTERPHASE: cell growth & DNA Replication makes up 90% of a cell’s life, which is spent growing, functioning, duplicating its organelles and DNA

2: Cell Division Mitosis: the division of the nucleus; results in 2 identical nuclei Consists of 4 phases: Prophase: each chromosome and its copy (sister chromatids) join up nucleolus becomes visible nuclear membrane breaks down centrioles move to opposite ends and form spindle fibres b. Metaphase: Sister chromatids line up along center of spindle fibres c. Anaphase: Sister chromatids are pulled apart to opposite ends of the poles d. Telophase: Nuclear membranes form around 2 new sets of chromosomes, spindle disappears, chromosomes lengthen and get thinner, nucleoli reappear

2: Cell Division - continues ii. Cytokinesis: division of organelles and cytoplasm into equal halves Animal cells: cell membrane pinches inward (furrow) until cell divides into two Plant cells: cell wall forms a cell plate which divides the 2 nuclei End result: 2 identical daughter cells!

Video: Mitosis—The Amazing Cell Process That Uses Division to Multiply