lecture 8 + 9 metabolism

Question 1

catabolism vs anabolism

Answer 1

catabolism: extract biologically useful energy from meals
anabolism: use this energy, and small molecules derived from food breakdown, to sythesize new biomolecules + cells

Question 2

the three pathways that can synthesize ATP

Answer 2

glycolysis

TCA cycle

electron transport system

Question 3

hydrolysis goes with (catabolism/anabolism) whereas condensation reactions go with (catabolism/anabolism)

Answer 3

hydrolysis = breaking down: catabolism

condensation = builidng- anabolism

Question 4

glycosidases

Answer 4

enzymes that break down sugars.

ex: lactase, sucrase

Question 5

which enzyme breaks down cleaving α-1,4 bonds

Answer 5

α-Amylase

this action initiaties digestion

Question 6

which enzyme takes over to help break down alpha 1,6 bonds?

Answer 6

α-dextrinase

‘limit dextrin’ when the enzyme has reached its limit of what it can cleave

Question 7

what happens to these glucose monomers once they are liberated by enzymes from the larger macromolecule

Answer 7

Once the subunits are hydrolyzed to individual sugars they are transported into the gut epithelial cells and out again on the basal surface to diffuse into the blood

Question 8

what do amino acids, dipeptides, and nitrogenous bases do once liberated from proteins/nucleic acids ?

Answer 8

they are transported into the gut epithelial cells and out again on the basal surface to diffuse into the blood

Question 9

____reactions require an input of energy either by coupling the + ΔGO synthesis reaction with ATP hydrolysis (-ΔGO) or by using the reducing power of NADPH2 (-ΔGO ) or both.

Answer 9

anabolic

(building things requires energy)

Question 10

_____reactions have -ΔG values.

Answer 10

catabolic (breaking something down release energy)

Question 11

T/F: the sum of catabolic and anabolic reactions must add to a - ΔG knot.

Answer 11

true

Question 12

Intermediary metabolism

Answer 12

integrated network of chemical reactions responsible for catabolism/anabolism

Catabolic and anabolic pathways connect in the “intermediary metabolic pathways” because subunits can change into intermediates at particular steps. Thus, intermediary pathways are amphibolic– can be used to either synthesize needed molecules or break molecules down in order to harvest energy in the form of ATP or store energy as glycogen and triglycerides.

Question 13

zymogens, and example of a famous one

Answer 13

The digestive enzymes of the pancreas are secreted as in-
active precursors called zymogens

ex: pepsinogen, the stomach digestion pre-enzyme

Question 14

trypsinogen

Answer 14

pancreatic zymogen trypsinogen is activated to form trypsin,
which in turn activates the remaining pancreatic zymogens necessary for digestion (lipases, etc)

Question 15

How is the energy released in the oxidation of a carbon compound converted into ATP?

Answer 15

The energy of oxidation is initially trapped as a high-phosphoryl-transfer-potential
compound and then used to form ATP.

Question 16

___ is a
major electron carrier in the oxidation of fuel molecules

Answer 16

NAD+

Question 17

the reduced form of electron carrier NAD+ is ___

Answer 17

NADH

Question 18

The electron donor in most reductive biosyntheses is ___which is different in that is has a phosphate group

Answer 18

NADPH

Question 19

Glucose is oxidized to pyruvic acid in the ____pathway

Answer 19

glycolytic

Question 20

Fatty acids and pyruvate are oxidized to CO2 and H2O in the ___

Answer 20

citric acid cycle

Question 21

As glucose is oxidized, what gets reduced?

Answer 21

NAD+ get reduced to NADH + H+ in glycolysis

Question 22

____ carries acetic acid or fatty acids in a thioester high energy linkage.

Answer 22

Coenzyme A

Question 23

All the subunits of the macromolecules (amino acids, sugars, nitrogenous bases, fatty acids, glycerol) can be catabolized to __, __ and __ using fermentation, cictric acid cycle, or ETC

Answer 23

CO2, H20, and NH3

Question 24

what are the 3 regulatory mechanisms that control which pathways are used?

Answer 24

1. Feedback regulation on allosteric enzymes that control a committed step
2. Repression or activation of genes to control the amount of new enzyme being synthesized
3. Accessibility of substrates (e.g., compartmentalize in an organelle)

Question 25

energy charge of the cell

Answer 25

Cells can monitor energy needs by adjusting enzyme activity based on the ratio of ATP to ADP (or NADP+ to NADPH). If ATP is plentiful then catabolic pathways are inhibited. If ADP is higher than ATP, then feedback inhibition ends.