ch 12: cell division

Binary fission

prokaryotic cell division

Which 2 types of cell division do eukaryotic cells have?

mitosis and meiosis

Mitosis

“normal” cell division used to create two cells, each identical to the original cell that divided

Meiosis

“special” cell division used to create haploid gametes

What are the haploid gametes in animals?

sperm and egg

What are the haploid gametes in flowering plants?

pollen and egg

Overview of binary fission process

prokaryotic cell replicates its DNA, cell grows larger, cell splits into two

Cell cycle

the repeatable process of preparing to divide and dividing

G1 phase

“growth” phase after previous cell division, before S phase

S phase/synthesis phase

phase where cell replicates its chromosomes/duplicates its DNA

Chromatid/sister chromatids

each of the two pieces of a replicated chromosome

Centromere

region of the chromosome that holds together the chromatid

G2 phase

second growth phase after S phase and before cell division

Mitosis/Meiosis

phase of actual cell division

What are the steps of the cell cycle?

G1 phase → S phase → G2 phase → mitosis/meiosis

What are the steps of mitosis?

prophase → prometaphase → metaphase → anaphase → telophase

True or False: Plants do not have centrioles

True

What 2/3 things happens during prophase?

chromosomes condense by wrapping around proteins. in animal cells, centrioles begin to migrate to opposite poles of the cell. spindle fibers begin to form in both animals and plants

How do chromosomes condense?

wrap around proteins and can become visible under light micrscope

What are spindle fibers made out of?

microtubules

What happens specifically in animal cells during prophase?

centrioles begin to migrate to opposite poles of the cell

What 4 things happens during prometaphase?

nuclear membrane is broken down. chromsomes condense further. spindle fibers grow and attach to chromosomes via kinetochores. spindle fibers begin to move chromosomes into position for metaphase.

What happens during metaphase?

chromosomes are lined up on metaphase plate

What 2 things happen during anaphase?

chromatids of each chromosome are pulled apart from each other by spindle fibers and move to opposite poles of the cell. sometimes cytokinesis occurs

Because of metaphase and anaphase what is guaranteed about the new cell?

each new cell will have identical sets of chromosomes/DNA

What 3 things happen during telophase?

two new nuclear membranes form. chromosomes in both nuclei de-condense. cytokinesis occurs.

Cytokinesis

division of cytoplasm

What is the difference in cytokinesis for animals and plants?

Animals: perform cytokinesis by cleavage furrow Plants: perform cytokinesis by cell plate

Cleavage furrow

a groove in the cell membrane which grows from the outside in until the cell is split in two

Cell plate

cell membrane and then cell wall forms in the center of the cell where the metaphase plate was and grows outward