ch 12 - [1/2 cell growth & division] human genetics

2 types of cells and the difference between them

• somatic cells: general term for a body cell (except for those producing eggs and sperm)

• germ cells: cells producing sperm and eggs - will produce gametes

what somatic cells contain within them

non-reproductive cells containing two copies of every chromosome (one copy received from each parent) - makes it a diploid cell

diploid

term for somatic cells because they contain two copies of every chromosome (2 complete sets of chromosomes)

haploid

cell containing one complete set of chromosomes (23 in total, whereas a diploid has 46 in total b/c it’s 2 sets from each parent)

# of chromosomes (individually and in pairs) within diploid somatic cells

individually - 46

in pairs - 23

provide names for:

pairs #1-22 of chromosomes within diploid somatic cell

pair #23 of chromosomes within diploid somatic cell

1-22 = autosomes (non-sex chromosomes)

23 = sex chromosomes (either X or Y)

which of the following divides?

somatic cells

give possible combos of x and y chromosomes in a human diploid

• X and X

• X and Y

• [Y and Y cannot exist; fatal combo]

cell cycle (def)

event sequence in a cell’s life allowing the parent somatic diploid cell to produce 2 daughter cells, genetically identical to its parent cell, by dividing itself

2 phases of the cell cycle

1. interphase

2. cell division/mitotic phase: mitosis and cytokinesis

interphase (def and phases)

phase majority of cells are in most of the time - period where cells are not dividing

phases

1. G1 = gap 1 phase where cell carries out normal metabolic functions - accumulates energy reseves and DNA building block mlcs

2. S = replication of cell’s DNA (each of the 23 chromosome pairs are copied), creating sister chromatids connected at centromere in cell

3. G2 = gap 2 phase where cell continues preparing for mitosis - organelles are duplicated, mitotic spindle is dismantled

g0 stage

inactive stage not in the cell cycle - cells are not actively dividing and are resting

cell division: mitotic phase (def and stages)

contents of the nucleus are divided and distributed, and duplicated chromosomes are aligned, separated, and moved to opposite poles of the cell

1. prophase

2. metaphase

3. anaphase

4. telophase

cytokinesis follows this

prophase

metaphase

anaphase

telophase

cytokinesis

meiosis

only part of the cell cycle for human germ cells (that form gametes)

produces 4 haploid daughter cells