m1 + 2 lect. - cell biology

Question 1

parts of a cell?

Answer 1

-cell membrane
-nucleus
-cytoplasm

Question 2

what cell barrier is semi-permeable?

Answer 2

cell membrane

Question 3

what can go through a semi-permeable barrier?

Answer 3

water-soluble molecules
- hydrophyllic
-polar +/-
electrolytes
proteins
- enzymes
-hormones
-neurotransmitters

Question 4

what is the RMP?

Answer 4

Resting Membrane Potential
- the polarity across the surface of the cell

Question 5

RMP is the resting membrane potential generated by regulating what two ions?

Answer 5

extracellur = Sodium (Na+)
intracellur = Potassium (K+)

Question 6

in what cells does this RMP become a functional process that allows the cells to transmit impulses?

Answer 6

impulses transmitted and received (dendritic endings) — action potential
- neurons
- muscle

Question 7

how does action potential begin?

Answer 7

• direct stimulation of a nerve ending
• neurotransmitter release at synapse

Question 8

neurotransmitter release due to ________, stimulates ___ _________ at the post synaptic membrane.

Answer 8

• calcium
• ion channels

Question 9

what is the level of stimulation called? (needed to activate action potential)

Answer 9

threshold (-55 nerve)

Question 10

the influx of what ion begins the depolarization wave?

Answer 10

sodium (Na+)

Question 11

what does an influx of sodium trigger to open?

Answer 11

voltage gated sodium channels,
causing the action potential across the cell in a wave-like fashion
-opens at threshold (-55)
closes at (+30)

Question 12

how long does depolarization last?

Answer 12

long enough to allow the influx of Na to change the membrane potential to a +30mV
- then Na gates close

Question 13

the release of what ion causes the repolarization wave?

Answer 13

potassium (K+)

Question 14

repolarization wave: what happens as soon as the Na gates close?

Answer 14

K gates then open, releasing K from the cell

Question 15

what happens when potassium is released during repolarization?

Answer 15

it lowers polarity back to a negative charge
+30mV —-> -55mV

Question 16

what pump is activated when the K gates are opened in the repolarization wave?

Answer 16

sodium/potassium pump
3 Na+ in/ 2 K+ out for every ATP

Question 17

what happens with hyperpolarization?
what might cause this?

Answer 17

in the presence of other chemicals, that allow the K gates to stay open

ex.) epinephrine/ norepinephrine inhibiting the visceral smooth muscle

Question 18

what process do cells use to generate energy?

Answer 18

cellular respiration (aerobic respiration)
- needs oxygen

Question 19

what two compounds are normally required for cellular respiration?

Answer 19

• glucose
• oxygen

Glucose + O2 => 36ATP + H20 + CO2 —-> exhaust

Question 20

what organelle is necessary for cellular respiration?

Answer 20

mitochondria

Question 21

where is aerobic respiration used? and for what activity?

Answer 21

in all tissue cells, to produce ATP necessary for all chemical and electrical activity

Question 22

what happens in glycolysis?

Answer 22

in cytoplasm, glucose is broken down into:
2 ATP
2 Pyruvic acid
2 NADH

Question 23

after glycolysis, what happens in the mitochondria?

Answer 23

2 ATP are used to turn 2 Pyruvic acids into Acetyl CoA, 2 NADH are produced also

Question 24

what happens in the kreb’s cycle?

Answer 24

in the mitochondria, the Acetyl CoA and O2 are consumed, producing:
2 ATP,
6 NADH,
2 FADH,
water and
CO2

Question 25

what happens in the electron transport chain (ETC)? and why?

Answer 25

coenzymes (NADH, FADH) are reduced and 34 ATP are produced

coenzymes are reduced to prevent free radical production —- damages cells and causes disease + cancer

Question 26

carb metabolism: polysaccharides (starches) are broken down into Di- and Monosaccharides by what enzymes?

Answer 26

-salivary amylase
-pancreatic amylase
-brush border enzymes

Question 27

all carbs are broken down into monosaccharides, what are the end products?

Answer 27

-glucose
-galactose
-fructose

all are lastly converted to glucose

Question 28

any excess carbs will be stored as glycogen or fat, due to:

Answer 28

insulin

Question 29

glycogenesis is:

Answer 29

creation of glycogen

Question 30

lipogenesis is:

Answer 30

creation of fat

Question 31

if not enough carbs, glycogenolysis (1) occurs:

Answer 31

the breakdown of glycogen at the liver and skeletal muscle due to glucagon

glucagon–> breaks things down

Question 32

if not enough carbs, gluconeogenesis (2) occurs:

Answer 32

used by diabetics, starving or those under stress to produce energy from non-carbohydrate sources

Question 33

in gluconeogenesis, lipolysis is:

Answer 33

the breakdown of fat

produces 2 Acetyl CoA for every fatty acid, then changes to ketones

Question 34

in gluconeogenesis, transamination/ urea’s cycle is:

Answer 34

breakdown of proteins

produces a kreb’s intermediate and urea –> eliminated in urine