Block 2

Question 1

Catabolic pathways

Answer 1

release energy by breaking down complex molecules to simpler compounds

Convergent
Exergonic
Oxidative

Products: ATP, FADH2, NADH, NADPH

Question 2

Anabolic pathways

Answer 2

consume energy to build complicated molecules from simpler compounds

Divergent
Endergonic
Reductive

Products: NAD+, FAD, ADP, NADP+

Question 3

Reduction

Answer 3

gains electrons and energy

Question 4

Oxidation

Answer 4

gives up electrons and releases energy

Question 5

Redox Rxn

Answer 5

Typically have NAD

Question 6

Intercellular

Answer 6

between cells

Question 7

Intracellular

Answer 7

signals ordinate within cells

Question 8

Signal Transduction

Answer 8

Receptors act as signal transducers. They bind to the extracellular signal and transmit the signal into the cell by promoting activation or synthesis of intracellular signaling molecules.

Extracellular signals are converted to intracellular signals in the target cell

Question 9

Features of Signal Transduction

Answer 9

Specificity, amplification (enzymes activate enzymes), desensitization/ adaptation (feedback circuit shuts off receptor), Integration (2 signals have opposite effects on a metabolic characteristic

Question 10

Intracellular second messengers

Answer 10

-The receptor activates a G-protein that stimulates an effector enzyme to produce a second messenger
-Nonprotein
cAMP
IP3
DAG
Ca2+
cGMP
Nitric Oxide (NO)

Question 11

First messenger

Answer 11

the hormone or neurotransmitter that binds to plasma membrane

Question 12

Steroid Receptor

Answer 12

Androgen or progesterone receptor

• Steroid binds to receptor in cytoplasm–> act as ligand-activated transcription factor –> activated receptor bind to DNA to alter the rate of gene transcription
• mechanism may take hours to days (slow)

Question 13

Gated ion channel

Answer 13

Nicotinic ACh, Gaba, Glycine receptors
Receptor linked to ligand or voltage-gated ion channel
-binding opens or closes channel deciding if ion gets through

Question 14

Enzyme receptor (catalytic)

Answer 14

Tyrosine kinase receptor

• catalyses production of a intrasignaling molecule
• Ex. Insulin receptor bind of ligand –> ATP cleavage, autophosphorylation and phosphorylation of specific tyrosine residues in target proteins –> signaling cascade and response activation

Question 15

G-Protein Coupled Receptor (GPCR)

Answer 15

Epinephrine/ Norepinephrine receptor (beta and alpha adrenergic)
-G protein activates enzymes that produce second messengers

Question 16

Signal Termination

Answer 16

Ex. Degradation of insulin, GTPase, hydrolysis of cAMP by phosphodiesterase, reversal of phosphorylation

Question 17

GLUT 1

Answer 17

Brain and RBC

Question 18

GLUT 2

Answer 18

Liver

Question 19

GLUT 3

Answer 19

Neurons, placenta, testes

Question 20

GLUT 4

Answer 20

Adipocyte, Skeletal and Cardiac muscle

• Insulin dependent
• Increases in number with the presence of insulin

Question 21

SGLT

Answer 21

Intestinal cells, Renal tubules

-secondary active transport

Question 22

Aerobic glycolysis

Answer 22

2 ATP
2 NADH

-Net loss of 2 ATP

Question 23

Anaerobic glycolysis

Answer 23

2 ATP

Question 24

Glucokinase

Answer 24

liver and beta cells of pancreas

• high Km (low affinity)
• high Vmax

Question 25

Hexokinase

Answer 25

All other tissues

• Low Km (high affinity)
• low Vmax