Bio test 3 reproduction at cellular level

Cell division

Copy chromosomes, sort chromosome, physically split cells

2 processes of cell division

mitosis and meiosis

Functions of mitosis

Asexual Reproduction, growth of multicellular organisms, repair and replacement of cells

Functions of meiosis

-gamete production in animals for sexual reproduction

-spore production in plants

Asexual reproduction

offspring are genetically identical to the parent

Ex; yeast, plant cuttings

Sexual reproduction

Offspring are similar but have variation

Eukaryotic chromosomes are made of

Chromatin

1 long dna molecule with structural proteins

Dispersed when cell is not dividing

Eukaryotic chromosomes condenses

Before cell division qnd are visible as chromosomes

In eukaryotic chromosomes before cell division,

Chromosomes replicate and form two copies called sister chromatids, joined together at the centromere

Interphase (G1, S, G2)

G1- growth, S- DNA replication, G2- final prep for division

order of the eukaryotic cell cycle

G1, S, G2, prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis

Prophase

Centrosomes move to opposite poles, microtubules energy from centrosomes forming spindle fibers, chromatin condenses forms visible chromosomes

Prometaphase

Nuclear envelope disappears, spindle fibers attach to centromeres, chromosomes begin to be moved to center

Metaphase

Mitotic spindle fully formed, chromosomes lined up along plate, sister chromatids face opposite poles

Anaphase

Centromeres come apart, sister chromatids separated and pulled to opposite poles, cell elongates

Telophase

Chromosomes decondense, mitotic spindle breaks down, nuclear envelope reforms, cell begins to physically divide

Cytokinesis

Cells physically separate, differs in animal and plant cells,

Cytokinesis plant cell

Plant- cell plate forms between cells, beginning of new cell wall

Cytokinesis animal cell

Animal- cell membrane pinches in the middle to form, cleavage furrow

Eukaryotic chromosomes

Are homologous pairs with somatic body cells of each species

Contain a specific number of chromosomes such as 46: 23 pairs

Human chromosomes

22 pairs are autosomes

Regular chromosomes

Each member of a pair are the same size genetic composition

Sex chromosomes

One pair that are different, determine the sex , x and Y chromosomes

Eukaryotic chromosomes are visible as

Karotypes

Eukaryotic chromosomes somatic body cells diploid

Diploid 2n, two sets of chromosomes means 2 number ones, 2 number 2s

Humans have 46

Eukaryotic chromosomes gametes

Eggs sperm

Haploid, one set of chromosomes means

Humans have 23

Fertilization in eukaryotic cells

Fertilization restores diploid number and forms 2n zygote