genetics

mitosis

formation of somatic (body) cells

meiosis

formation of gametes (eggs, sperm)

homologus chromosomes

pair of chromosomes

one from each parent

crossing over

exchange of genetic information between two chromosomes in a homologus pair

mitosis and meiosis interphase

46 chromosomes cloned

forming 92 chromatids joined at the centromere

mitosis prophase

chromosomes condense

pro = “before”

mitosis metaphase

chromosomes line up in the center single-file

m = “middle”

mitosis anaphase

chromatids separated by spindle fibers

mitosis telophase

chromatids reach opposite sides of the cell to form new chromosomes

cytokinesis — cell separates into 2

steps of mitosis/meiosis

1. interphase

2. prophase

3. metaphase

4. anaphase

5. telophase

meiosis prophase 1

chromosomes condense

homologus pairs form and cross over

meiosis metaphase 1

homologus pairs line up in the center of the cell, forming 2 lines

meiosis anaphase 1

chromosomes separate from their pair by spindle fibers

meiosis telophase 1

chromosomes reach opposite sides of the cell and nuclear envelops form around them

cytokinesis — cell separates into 2

cytokinesis

in mitosis and meiosis, cytoplasm splits and form two cells

meiosis prophase 2

after cytokinesis, chromosomes in two diploid cells condense

meiosis metaphase 2

chromosomes line up in the middle of both cells single-file

meiosis anaphase 2

chromatids separate by spindle fibers

meiosis telophase 2

chromatids reach opposite ends of the 2 cells and are captured by nuclear envelops

cytokinesis — 2 cells separate into 4 gametes containing 23 chromosomes (haploid cells)

fertilization

fusion of a sperm and egg cell (23 chromosomes each)

forms a zygote (diploid cell, 46 chromosomes)

heredity

the transmission of traits from parents to offspring

what are nucleic acids made of?

1. deoxyribose (a sugar)

2. phosphate

3. nitrogenous base

structural genes

segments of chromosomes that code for the synthesis of proteins that form a certain trait

regulatory genes

segments of chromosomes that are activated and deactivated by other genes

control gene expression

mRNA

carries genetic information from DNA to make proteins

rRNA

found in ribosomes

the site of protein synthesis

tRNA

transfer amino acids to the ribosome for protein synthesis

transcription

RNA polymerase attaches complimentary bases to the DNA, forming a single strand of mRNA

mRNA is transported from the nucleus to ribosome for translation

translation

tRNA carrying an amino acid binds to a complimentary codon in the mRNA at the ribosome, forming proteins