Ex 4

plasma membrane

controls movement of substances into and out of the cell

microvilli

folds of the plasma membrane that increases the surface area of the cell to increase absorption or secretion

nucleus

contains DNA molecules and nucleolus

nucleolus

assembly site for ribosomes

chromatin

long thin strands within nucleus; each strand composed of one DNA molecule and associated proteins

cytoplasm

area of the cell between plasma membrane and nucleus; includes cytosol and organelles

cytosol

fluid portion of cytoplasm in which many of the cells’ chemical reactions occur

mitochondria

makes ATP via aerobic cellular respiration

ribosomes

site of protein synthesis in cytosol and Rough ER

rough endoplasmic reticulum

synthesize proteins and phospholipids used in the plasma membrane and organelles or secreted via exocytosis

smooth endoplasmic reticulum

fatty acid and steroid synthesis; detoxifies toxic substances; stores calcium

golgi complex

receives and modifies proteins from Rough ER; sorts and modifies them for transport

secretory vesicles

secrete substances outside the cell by exocytosis

lysosomes

enzymes digest and recycle worn-out organelles and substances entering the cell; can digest the cell

peroxisomes

produce hydrogen peroxide; detoxify harmful substances

cytoskeleton

three kinds of protein filaments; maintain cell shape and involved in cell movement and movement of organelles

centrosomes

form mitotic spindle; needed to form cilia and flagella

cilia

abundant, hair-like projections that move fluids and particles along the cell surface

flagella

long cell projection; whip-like motion moves sperm

interphase

cells are metabolically active and growing;

mitotic phase

somatic cell division

mitosis

nuclear division

prophase

nucleolus and nuclear membrane disappear; chromatin condenses into chromosomes; centrioles move to opposite poles; spindle fibers form

metaphase

chromosomes line up at metaphasal plate; spindle fibers attach to centromeres of chromatids

anaphase

chromatids of chromosomes separate; move to opposite poles

telophase

cell reverses prophase activities

cytokinesis

cytoplasmic division into two genetically identical daughter cells; begins during anaphase with formation of cleavage furrow; ends with completion of telophase

G1 phase

cell metabolically active; duplicates organelles and cytosolic components; centrosome replication begins(8-10 hours)

S phase

DNA replicated(8 hours)

G2 phase

cell growth continues; enzymes and other proteins are synthesized; centrosome replication completed(4-6 hours)