Biology 101 Chapters 6 And 7

Front 1

Def: A complex of proteins and DNA. (102)

Back 1

Chromatin

Front 2

Def: a netlike array of protein filaments that maintains the shape of the nucleus by mechanically supporting the nuclear envelope. (102)

Back 2

Nuclear lamina

Front 3

True or false?
The nucleus contains the genes in the eukaryotic cell.
(102)

Back 3

False; some genes are located in the mitochondria and chloroplasts.

Front 4

What two materials make up ribosomes? (102)

Back 4

Protein and ribosomal RNA

Front 5

What's the difference between free ribosomes and bound ribosomes?

Back 5

Free ribosomes are suspended in the cytosol and produce proteins that are used within the cytosol. Bound ribosomes are attached to the outside of the endoplasmic reticulum or nuclear envelope, and make proteins that are destined either for insertion into membranes, for packaging within organelles such as lysosomes, or for secretion.

Front 6

Def: Flattenedmembranous sacs that make up the Golgi apparatus. (105)

Back 6

Cisternae

Front 7

What are the two poles of a Golgi sac? (105)

Back 7

a)the cis face, which receives vesicles
b)the trans face, which ships vesicles

Front 8

Def: a process used by the hydrolytic enzymes in lysosomes to recyle the cell's own organic material. (107)

Back 8

Autophagy

Front 9

What are the three main types of fibers that make up the cytoskeleton, and what are their functions? (113)

Back 9

a)Microtubules: cell motility, act as "girders" in cell shape, organelle movements.
b)Microfilaments: muscle contraction, cell division, maintenance of cell shape, act as "steel cables"
c)Intermediate filaments: anchorage of nucleus and certain other organelles, formation of nuclear lamina

Front 10

What protein subunits make up microtubules, microfilaments, and intermediate filaments? (113)

Back 10

Microtubules - tubulin
Microfilaments - actin
Intermediate filaments - several types of the keratin family

Front 11

What are the 3 main types of intercellular junctions? (120)

Back 11

a)tight junctions
b)desmosomes
c)gap junctions

Front 12

What's the main function of tight junctions? (121)

Back 12

Tight junctions bind neighbouring cells very tightly together to prevent leakage of extracellular fluid across epithelial cells.

Front 13

What's the main function of desmosomes? (121)

Back 13

The main function of desmosomes is to anchor cells together into strong sheets, acting as rivets.

Front 14

What's the main function of gap junctions? (121)

Back 14

The main function of gap junctions is to provide cytoplasmic channels from one cell to an adjacent cell.

Front 15

Def: A molecule that has both a hydrophobic and a hydrophilic region. (124)

Back 15

Aphipathic molecule

Front 16

Why must cell membranes be fluid to work properly? (127)

Back 16

To retain their permissive permiability.

Front 17

Why is cholesterol so crucial to the cell membrane? (127)

Back 17

Cholesterol acts as a "temperature buffer", resisting changes in membrane fluidity that are caused by temperature changes.

Front 18

True or false? Saturated hydrocarbon tails have kinks that keep the molecules from packing together, enhancing membrane fluidity. (126)

Back 18

False; It is unsaturated hydrocarbon tails that do so.

Front 19

Name 6 functions performed by proteins of the plasma membrane. (128)

Back 19

a)transport
b)enzymatic activity
c)signal transduction
d)cell-cell recognition
e)intercellular joining
f)attachment to the cytoskeleton and extracellular matrix

Front 20

What's the difference between integral proteins and peripheral proteins? (128)

Back 20

Integral proteins span the membrane, while peripheral proteins remain on the cytoplasmic side of the membrane, sometimes attaching to the integral proteins.

Front 21

Name 5 particles or molecules that require the cell's help crossing the membrane. (131)

Back 21

a)ions
b)polar molecules
c)sugars
d)water
e)charged atoms

Front 22

How does an animal cell react to an environment that has
a)more solute
b)less solute
(132)

Back 22

a) It is in a hypertonic environment, and will shrivel and die.
b)It is in an area that is hypotonic, and will burst.

Front 23

Def: An organelle that aids in osmoregulation in cells with cell walls. (132)

Back 23

Contractile vacuole

Front 24

Def: Very firm, full of water. (132)

Back 24

Turgid

Front 25

Def: Limp, lacking water. (133)

Back 25

Flaccid

Front 26

Def: When cells aid polar molecules and ions in diffusion with integral transport porteins. (133)

Back 26

Facilitated diffusion

Front 27

Name two types of transport proteins that carry out passive diffusion. (134)

Back 27

a)channel protein
b)carrier portein

Front 28

What are the 6 steps in the sodium-potassium pump cycle? (135)

Back 28

1)Cytoplasmic sodium binds to the pump.
2)This binding stimulates phosphorylation by ATP.
3)Phosphorylation causes the protein to change its conformation, resulting in the expulsion of the sodium.
4)Extracellular potassium binds to the protein, triggering the rrelease of the phosphate group.
5)The loss of the phosphate restores the protein's original conformation.
6)The potassium is released and the sodium sites are receptive again.

Front 29

What is the membrane potential? (135)

Back 29

-50 to -200 millivolts

Front 30

Def: A transport protein that generates voltage across a membrane. (136)

Back 30

Electrogenic pump

Front 31

Def: The main electrogenic pump of plants, fungi, and bacteria. (136)

Back 31

Proton pump

Front 32

Def: The coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient. (136)

Back 32

Cotransport

Front 33

Def: a molecule that binds specifially to a receptor site of another molecule. (137)

Back 33

Ligand

Front 34

What technique is used by the cell to acquire bulk quantaties of a specific substance? (138)

Back 34

Receptor-mediated endocytosis