Biology exam 2

Membrane permeable solute

Moves to balance concentrations (diffusion)

Membrane impermeable solute

Water moves instead to balance concentrations (osmosis)

Diffusion

Molecules move down the concentration gradient

osmosis

water moves towards higher solute concentration

Hypotonic Definition

Solution has lower solute than cell

Hypotonic water movement

Water into cell

Hypotonic cell effect

Cell swells, possible lysis

Hypertonic definition

Solution has higher solute than the cell

Hypertonic water movement

Water out of cell

Hypertonic cell effect

Cell shrinks

Chromosome

Condensed dna

Chromatid

One copy of a duplicated chromosome

Sister chromatids

Identical copies connected at the centromere

Homologous chromosomes

Pair, one from each parent, with same genes but possibility different alleles

G1

Growth, normal cell functions

S

DNA replication

G2

Preparation for mitosis, organelles duplicate

M

Division of nucleus and cytoplasm

Prophase

Chromosomes condenses, spindle forms

Metaphase

Chromosomes line up at cell equator

Anaphase

Sister chromatids separate to opposite poles

Telophase

Nuclear envelope reforms, chromosomes decondense

Nondisjuction

Failure of chromosomes to separate properly, leads to abnormal chromosomes number

G1 checkpoint

Checks cell growth and dna integrity

G2 checkpoint

Ensures dna replicated correctly

M checkpoint

Ensures chromosomes are attached to spindle fibers