Cell Cycle and Mitosis

DE Bio Unit 4

mitosis

the division of the nucleus and the repeating sequence of cellular growth and division during the life of an organism

DNA=

deoxyribonucleic acid

proteins determine traits, DNA ____ for traits

codes

when the cell is using DNA it is stretched into thin strands called…

chromatin

just before cell division, chromatin coils around proteins and forms…

chromosomes

chromosomes are more __________ than chromatin

compact and easier to move around the cell

just before cell division, chromosomes are copied, these are called…

chromatids

when chromosomes are copied into chromatids, they are combined at the…

centromere

the “x” shape is _____ of one chromosome

2 copies

during cell division, the copies are…

split between the new cells

The Main Goal of Cell Division:

to give each new cell a copy of the original DNA

cell division allows multicellular organisms to…

grow, develop, and repair tissue

G1 (First Growth Phase)

the cell grows, functions, and duplicates organelles

S (Synthesis)

DNA is copied

G2 (Second Growth Phase)

the cell prepares to divide and makes parts that are needed for cell division

M (Mitosis)

division of the nucleus

C (Cytokinesis)

division of cytoplasm

interphase makes up about ___% of a cell’s life

80

Mitosis (PMAT) makes up about ___% of a cell’s life

20

Prophase

nucleus membrane disappears, spindle fibers form, DNA condenses into chromosomes

Metaphase

chromosomes line up in the middle, spindle fibers attach to chromosomes

Anaphase

chromosomes separate at the centromere, sister chromatids go to opposite ends

Telophase

chromosomes unwind into thin strands of DNA (chromatin), spindle fibers disappear, nucleus reappears in both cells

cytokinesis in animal cells

cells pinch in half

cytokinesis in plant cells

a cell plate forms

what is differentiation?

when stem cells become different specialized types of cells

why do cells divide?

growth, repair

why are checkpoints important during the cell cycle?

the cell can check to make sure it is growing and replicating material properly

what are some factors that can affect checkpoints?

environmental factors (radiation, carcinogens, diet, etc) can trigger the system to no longer work properly

is a high mitotic index normal?

it could cause irregular cell growth, indicating cancer cells

what is cancer?

uncontrolled cell growth

mitotic index is found by…

the number of cells dividing (PMAT) divided by the total number of cells