class 2: cell biology

Question 1

eukaryotes characterized by

Answer 1

membrane bound organelles

Question 2

cell membrane composed of

Answer 2

double layer of phospholipids, with proteins embedded

Question 3

functions of cell membrane

Answer 3

gives form to cell, cell signaling, controls passage of materials in and out of cell - selectively permeable

Question 4

function of proteins within the plasma membrane

Answer 4

provide structure, catalyze reactions, act as receptors and antigens

Question 5

integral/intrinsic proteins

Answer 5

span the plasma membrane

Question 6

peripheral/extrinsic proteins

Answer 6

embedded in only one face of the plasma membrane

Question 7

glycocalyx definition

Answer 7

glycoproteins and glycolipids on surface of the membrane

Question 8

glycocalyx function

Answer 8

identify the cell as self to the immune system

Question 9

active vs. passive transport

Answer 9

active uses ATP, passive does not

Question 10

carrier-mediated transport vs non carrier-mediated transport

Answer 10

non-carrier mediated involves diffusion - moving down the concentration gradient

Question 11

simple diffusion

Answer 11

non-carrier mediated and passive: lipid-soluble molecules pass through the membrane

Question 12

diffusion of ions

Answer 12

non-carrier mediated and passive: ions pass through membrane channel proteins

Question 13

diffusion of water (osmosis)

Answer 13

non-carrier mediated and passive: water diffuses through aquaporins

Question 14

facilitated diffusion

Answer 14

carrier-mediated and passive: carrier protein in membrane binds to target and changes shape to allow the target into the cell - does not use ATP (e.g. glucose)

Question 15

active transport

Answer 15

carrier-mediated and active: uses a pump to transport molecules against their concentration gradient - uses ATP! Primary: hydrolysis of ATP directly responsible for pump action; secondary: co-transport of Na+ is necessary for transport, ATP used indirectly.

Question 16

junctional complexes definition

Answer 16

intercellular junctions between epithelial cells that restrict the flow of molecules across epithelium

Question 17

types of junctional complexes

Answer 17

zonula occulens/tight junction, zonula adherens, macula adheres/desmosomes, gap junctions

Question 18

zonula occulens/tight junctions

Answer 18

no space between cells, proteins span between cells and are anchored in place, circumferential (at top)

Question 19

zonula adherens

Answer 19

proteins anchored in either cell interact, circumferential, not as tight as zonula occulens

Question 20

macula adherens/desmosomes

Answer 20

cell “buttoned” together by desmosomal proteins

Question 21

gap junctions

Answer 21

connections in cell membrane create “bridge” across cells, often allow ions through

Question 22

cytoplasm

Answer 22

material inside cell (except nucleus) - cytosol and organelles

Question 23

cytoskeleton

Answer 23

lattice work of microfilaments and microtubules that offer support and assist in movement and intracellular transport

Question 24

lysosomes

Answer 24

membranous sac that digests foreign molecules and damaged organelles through endocytosis, exocytosis, autophagy, etc.

Question 25

peroxisomes

Answer 25

membranous vesicle that contains enzymes to detoxify harmful molecules and break down hydrogen peroxide

Question 26

mitochondria

Answer 26

provide cellular energy via ATP production (ETC). the folds called crustal in the inner membrane increase surface area. They have their own DNA - more from mother than father

Question 27

ribosomes

Answer 27

composed of large and small subunit, each composed of protein and ribosomal RNA. They are very small, nucleic acid dense, and are the protein factories of the cell.

Question 28

endoplasmic reticulum

Answer 28

continuous with the outer layer of the nuclear envelope

Question 29

smooth ER

Answer 29

lacks ribosomes, metabolizes non polar compounds, stores CA2+ in striated muscle

Question 30

rough ER

Answer 30

has ribosomes, assists in protein synthesis and transport to Golgi

Question 31

Golgi body

Answer 31

processes (adds oligosaccharides and lipids) and packages macromolecules into vesicles. The convex side close to rough ER receives proteins, concave side away from Er secretes processed proteins

Question 32

nucleus

Answer 32

center for genetically determined info in eukaryotic cells

Question 33

heterochromatin

Answer 33

nuclear DNA that is tightly wound, dense

Question 34

euchromatin

Answer 34

nuclear DNA that is relaxed, capable of being transcribed

Question 35

nuclear envelope

Answer 35

inner + outer membrane of the nucleus

Question 36

nucleolus

Answer 36

within nucleus, where ribosomal DNA is made

Question 37

membrane potential

Answer 37

difference in electrical charge from inside of a cell to outside of a cell - inside is generally - due to phosphate groups and charged proteins, attracts + ions, which then leave along concentration gradient, K+ more permeable than other ions

Question 38

equilibrium potential

Answer 38

describes voltage across cell membrane if only 1 type ion could diffuse

Question 39

Nernst equation

Answer 39

calculates the equilibrium potential when ion concentration is known

Question 40

cell signaling

Answer 40

cell communication usually occurs through regulatory molecules secreted into extracellular fluid

Question 41

types of cell signaling (across gap junctions, regulator flows directly from one cell to another)

Answer 41

paracrine, autocrine, endocrine

Question 42

paracrine signaling

Answer 42

cell releases molecules that act on nearby targets

Question 43

autocrine signaling

Answer 43

regulatory molecules act on the cells that released them

Question 44

endocrine signaling

Answer 44

cell releases regulatory molecules (hormones) into blood, which act on cells in another organ

Question 45

polar vs. non polar cell signaling

Answer 45

non polar regulators can penetrate the PM, while polar regulators must bind to receptor proteins on surface, using a secondary messenger like G proteins