Metabolism 1

Question 1

Metabolic syndrome: associated with?

Answer 1

risk of developing cardiovascular disease and type 2 diabetes

Question 2

2 key principles of metabolic pathways

Answer 2

all obey the same fundamental principles. not all reactions occur in every organism or every cell.

Question 3

two major purposes of metabolism

Answer 3

obtain usable chemical energy from environment. make specific molecules that cells need to live and grow

Question 4

two major types of metabolic pahtways

Answer 4

catabolic: breaking down complex molecules, make ATP. anabolic: building complex molecules from simple precursors.

Question 5

catabolic vs. anabolic: ox or red?

Answer 5

catabolic = oxidative, remove electrons from molecules. anabolism = reductive, require electrons to make bonds.

Question 6

metabolic pathway: definition

Answer 6

series of consecutive, enzyme catalyzed reactions producing a specific product from a specific starting metabolite (ex: glycolysis)

Question 7

concentrations of metabolic intermediates are maintained at ____? through which two types of reactions?

Answer 7

steady levels: irreversible, rate-limiting reactions that are tightly regulated, and regulated in concert. reversible reactions that are not regulated, direction depends on [intermediates].

Question 8

Pathways are ___, but ____ occur. What is shared? Regulation?

Answer 8

directional, aka irreversible - but opposing pathways do occur. share reversible reactions, but always have unique irreversible steps. reciprocally regulated so only one is operational at a time.

Question 9

biomolecules are broken down to ____ which feeds into ____ and is broken down to ____. what happens to the electrons?

Answer 9

acetyl co A –> CAC –> Co2. Electrons from acetyl co A are “saved” in electron carriers aka enzyme cofactors: NADH and FADH2.

Question 10

reduced electrons carriers NADH and FADH2: what happens to them? requires? produces?

Answer 10

re-oxidized via ETC; requires oxygen and produces ATP.

Question 11

fuel supplies (which 2?) in the blood stream are managed by the ___, which processes them in what 3 ways?

Answer 11

glucose and fatty acids (aas not usually used as fuel). managed by the liver - uses them, storage as glycogen, processes/stores/releases as needed.

Question 12

how is excess fuel (2) stored?

Answer 12

glucose stored as glycogen in liver and skeletal (also cardiac muscle). fatty acids stored as TAGs in adipocytes.

Question 13

2 fuel users? providers?

Answer 13

users: brain and skeletal muscle. providers: liver and adipose tissue.

Question 14

brain is a ___ fuel user: why?

Answer 14

obligatory: need lots of ATP to maintain ion concentration gradients; ALWAYS needs some glucose.

Question 15

liver as a fuel provider: maintains?

Answer 15

suitable levels of fuel molecules in blood for use of all other tissues.

Question 16

primary function of adipose tissue

Answer 16

long term storage of energy

Question 17

our nutritional status (___ or ___) is signalled by?

Answer 17

fed or fasted; signalled by hormones

Question 18

fed state: signal, response, cellular effects, mode of action?

Answer 18

increasing [glucose] in blood –> insulin release –> promotes use and storage of fuel molecules –> insulin activates phosphatases in target cells, and dephosphorylates target enzymes

Question 19

fasted state: signal, response, cellular effects, mode of action?

Answer 19

decreasing blood [glucose] –> glucagon release –> promotes mobilization of fuel stores via activation of protein kinases aka phosphorylation of target enzymes

Question 20

glucose is broken down aka ___, by? synthesized by?

Answer 20

catabolized by glycolysis. synthesized by gluconeogenesis.

Question 21

glucose stored as ___ via ____, released by ______?

Answer 21

glycogen, glycogen synthesis. released by glycogen breakdown aka glycogenolysis.

Question 22

glycolysis: starts with? ends with? occurs in ___ cells? where in the cell? aerobic?

Answer 22

glucose –> pyruvate. in all cells: cytoplasm. anaerobic.

Question 23

glycolysis: 2 rate limiting steps?

Answer 23

2 RLS regulated in parallel, catlyzed by PFK 1 and PK

Question 24

glycolysis rate determined by what two things?

Answer 24

substrate availability (glucose concentration maintained by liver, and rate of transport into cells via GLUT). alterations in activity of rate limiting enzymes (allostery and reversible covalent modifications like phosphorylation)