Mitosis vs meiosis

3 most common types of gene mutations

1.) point mutation: one base is substituted for another

2.) insertion: an extra base(s) are inserted

3.) Deletion: of a base(s)

when does gene mutation normally occur?

most genes errors occur during DNA replication for cell division

chromatid

one half of a duplicated chromosome formed during DNA replication, each half is a complete DNA copy

2 chromatids together and connected, until readying to separate during cell division

cell cycle

• process of making new cells

• most of it is taken up by Interphase (growing cell, replicating DNA, cell functions)

• only 10% is mitosis (division and making more cells)

mitosis

• when your body cells replicated their DNA and divide in order to promote growth and repair of damage or replace worn out body cells

• result is identical cells

Phases of Mitosis

PMAT

Prophase — nucleus still there, chromosomes condensing

Metaphase — chromosomes line up in middle of cell, nucleus no longer there

Anaphase — chromosomes move (A)way to opposite sides of cells; spindle fibers move them

Telophase — chromosomes have finished moving to far sides, new nuclei are forming around chromosomes on each side

cytokinesis - split the cell into two

number of chromosomes in a normal body cell?

46

meiosis

• process that makes gametes (egg and sperm)

• contributes to genetic variety

• involves going through cell division TWICE

number of chromosomes in gametes?

each sperm or egg cell has just 23 chromosomes

Reduction Division

a process where the starting cell has twice as many chromosomes as the results cells

what happens before meiosis starts (and mitosis, too)?

Interphase stage: cell is growing, replicating DNA and carrying out cell processes

How many chromatids will you have after replication?

92 chromatids, 46 centromeres, 46 unique chromosomes

How Meisosis differs from Mitosis

• You need to divide twice, not just once

haploid (n)

• one version of each chromosome type

• 23 total chromosomes

• (in humans - eggs and sperms are haploid cells; when they join together they become diploid)

diploid (2n)

• cell w/two versions of each chromosome type

• 1 version from each parent

• in humans these are body cells

autosomes

• chromosomes that are not sex chromosomes

• there are 22

sex chromosomes

• 1 set

• x or y

What type of cells do you have when you start Mitosis?

diploid

type of cells you have when you end mitosis?

diploid

type of cells you have when you start MEIOSIS?

diploid

Type of cells you have when you END MEIOSIS 1 or 2?

Haploid

homologous pairs

• genes pair up to ones of the same size & that contain the same kinds of genes in the same locations

• on from mom and 1 from dad

crossing over

• where chromosomes can overlap inProphase I of Meiosis and transfer genetic info.

• results in recombinant chromosomes

Metaphase I in Meiosis

chromosomes still line up in the middle, but it’s in pairs (2 pairs side by side)

Anaphase ! in Meiosis

the chromosomes (NOT chromatids) that get pulled to each side of the cell

Telophase 1 in Meiosis

same as in Mitosis; nuclei start to form around chromosomes on both sides of the cell

cytokinesis

• cell divides into 2

FINAL RESULT OF MITOSIS AND MEIOSIS

• RESULT in MITOTIS: 2 new, identical diploid cells (body cells)

• RESULT IN MEIOSIS: 4 non-identical haploid cells (gametes)/ half the # of the original cell