Miosis, Mitosis, Punnet Squares

chromosomes

carries DNA, packaged by histones + proteins

histone

proteins that package chromosomes into chromatin

centromere

connects chromatids together

chromatid

one strand of a chromosome

sister chromatids

two chromatids, a chromosome

homologous chromosomes

two chromosomes with similar genes that sit together

haploid

1 set of chromosomes, gametes (n)

diploid

2 sets of chromosomes, humans (2n)

Interphase

g1, s, g2

G1

cells grows and copies organelles

S

DNA replication (23 pairs, 46 chromosomes double)

G2

More cell growth, organelles, and proteins develop and mature

G0

Not a part of the cell cycle. Quiescent cells perform their functions without ever dividing. They have a particular life function and when they die there is no offspring. Ex: neurons, RBCs

Euchromatin

DNA is less condensed and loosely contained. Has an active form that can be accessed by RNA polymerase for transcription

Heterochromatin

Tightly wrapped, heavily condensed, cannot be transcribed, not active

Prophase

Nucleolus and nuclear envelope disapears

Centromeres move to opposite poles

microtubules extend between centrosomes

Sister chromatids coil tightly and become visable

centrosome

holds miotic spindle

prometaphase

microtubules extend and form miotic spidle

sister chromatids attach to microtubules at centromere

metaphase

chromosomes go to middle of the cell and are their most visable

Anaphase

cell elongates

sister chromatids are split at the centromere and pulled towards their centrosome

telophase

chromatids decompose at opposite poles

miotic spindle breaks down and nuclear envelope forms

Cytokinesis

Cell physically splits

Animal cytokinesis

Actin forms a ring called cleavage furrow and pinches the cell apart

Plant cytokinesis

Golgi apparatus makes vesicles lined up at the middle acting like a cell wall that then splits creating two cells

Mitosis

genetically same cells (2n → 2n)

Miosis

genetically differing gametes (n)(2n → n)

prophase I

miosis: chromosomes condense, nuclear envelope breaks, homologous chromosomes cross over

prometaphase I

miosis: microtubules spread across the cell, centrosomes go to opposite sides of the cell

metaphase I

miosis: tetrads (4 chromosomes) moves to mid line with homologous pairs randomly orientating themselves

anaphase I

miosis: microtubules pull apart chromosomes

telophase I

miosis: chromosomes at opposite poles, everything reverses, physical seperation, haploid daughter cells

prophase II

miosis II: chromosomes condense, nuclear envelope breaks, centrosomes move to opposite poles

prometaphase II

miosis II: nuclear envelope is gone, microtubules attach to centromere of sister chromatids

metaphase II

miosis II: sister chromatids are condensed and at the midline of the cell

anaphase II

miosis II: sister chromatids are pulled apart and at opposite sides of the cell

telophase II

miosis II: chromatids decondense, nuclear envelope is back, cells seperates into four haploid cells (n)

Gregor Monk

studied pea plants, founding father of genetics

Principal of Segregation

people have two alleles and passes one to their offspring

dominant and recessive genes

homozygous, heterozygous, homozygous

genotyoe

phenotype

genotype

homozygous dominant and recessive, heterozygous

phenotype

observable traits (color, size, etc…)

Law of individual assortment

inheritance of a gene is independent of inheritance of another

monohybrid square

one trait

dihybrid square

two traits

sex linked

Alleles is only on x chromosome

incomplete dominance

two dominant alleles resulting in mixed phenotype (black + white → gray)

codominance

dominant alleles expressed at the same time (black and white feathers)