carb review

Question 1

Simple carbs

Answer 1

monosaccharides and disaccharides

Question 2

complex carbs

Answer 2

oligosaccharides and polysaccharides

Question 3

What is the storage form of carbohydrates in plants?

Answer 3

starch

Question 4

amylose

Answer 4

straight chain

Question 5

amylopectin

Answer 5

branched chain

Question 6

What is the storage form of glucose in humans/animals?

Answer 6

glycogen

Question 7

digestion of carbs

Answer 7

oCarb into mouth
oSalivary amylase turns it into poly and disaccharides
oGoes through stomach
opancreatic amylase in the duodenum
oTurns into disaccharides then goes through epithelium of small intestine
oDisaccharides turn into monosaccharides

Question 8

what happens during SGLT1

Answer 8

glucose into enterocytes

Question 9

GLUT 4

Answer 9

requires insulin to function

Question 10

GLUT5

Answer 10

fructose absorption

Question 11

How do these transporters work? Are there an active transporter or work through facilitated diffusion?

Answer 11

• bind glucose on external side of the cell membrane
• undergo conformational change and transport glucose into the cell
• fructose works through facilitated diffusion

Question 12

Which transporter is insulin-dependent? How does it work? What will happen if this transporter does not respond to insulin?

Answer 12

• GLUT4
  
  • in resting state, transporters are found in vesicles inside the cell and don’t allow glucose entry
  • when activated GLUT 4 transporter laden vesicles migrate membrane to allow glucose entry by facilitated diffusion
  • if the transporter does not respond to insulin then there will be too much glucose in the blood.

Question 13

Anabolism

Answer 13

Anabolic reactions involve the building of larger, complex molecules from smaller, simpler ones, and require an input of energy

Question 14

Catabolic action

Answer 14

Catabolic reactions are the opposite of anabolic reactions, and break the chemical bonds in larger, more complex molecules

Question 15

major events of ATP synthesis

Answer 15

Glycolysis
Transition reaction
Citric Acid Cycle
Electron transport chain

Question 16

which event of ATP synthesis occurs in the cytosol

Answer 16

glycolysis

Question 17

which event of ATP synthesis occurs in the mitochondria

Answer 17

citric acid cycle

Question 18

hexokinase in the first step of glycolysis

Answer 18

in non liver cells
Inhibited by glucose-6-P
Catalyzes first reaction of glycolysis

Question 19

glucokinase in the first step of glycolysis

Answer 19

in liver cells
Active only at high glucose
Not inhibited by glucose-6-P

Question 20

Phosphofructokinase

Answer 20

Rate-limiting step, negatively regulated by ATP concentrations
-Inhibition of phosphofructokinase when ATP is high prevents breakdown of glucose in a pathway whose main role is to
make ATP

Question 21

what step produces ATP

Answer 21

5th step 1,3-bisphosphoglycerate + ADP 🡨🡪 3-phosphoglycerate + ATP

Question 22

Pyruvate kinase

Answer 22

Last step of glycolysis, produces pyruvate. At high glucose concentration, pyruvate kinase synthesis increases and excess glucose shuffle to make acetyl-CoA for fat synthesis. At low glucose/low energy level, pyruvate generally convert to acetyl-CoA and enter kreb’s cycle to make ATP

Question 23

Which steps are irreversible???

Answer 23

Hexokinase
PFK
Pyruvate kinase

Question 24

How many total ATP is produced from glycolysis per glucose??

Answer 24

2

Question 25

What happen when oxygen is absent/anaerobic respiration?

Answer 25

-Pyruvate will convert to lactate (instead of Acetyl-CoA)
-Lactate will be transported to Liver. In the liver, it will convert lactate to glucose (gluconeogenesis) – this is referred to as “Cori’s cycle”

Question 26

TCA cycle/citric acid cycle/kreb’s cycle

Answer 26

Intermediates form during glycolysis enters TCA cycle in the form of acetyl-CoA
Acetyl-CoA + Oxaloacetate forms citrate and this initiates TCA cycle

Question 27

products of Kreb’s cycle

Answer 27

2 CO2, 3 NADH, 1 FADH2, 1 ATP, 1 CoA

Question 28

what does the electron transport chain do

Answer 28

generate ATP through passing electrons from molecule to molecule to release energy
- ETC takes up electrons from all intermediates from glycolysis/Kreb’s cycle to generate the proton pumps. This creates a proton gradient to allow the ATP synthase to work, hence generating ATP.

Question 29

What is the final electron acceptor in ETC? What does it produce?

Answer 29

The final electron acceptor is oxygen, adding hydrogens from the concentration gradient to make water

Question 30

Describe how many ATP are produced during glycolysis, Kreb’s cycle, and pyruvate 🡪 acetyl-CoA, how many total ATP produced PER GLUCOSE?

Answer 30

glycolysis- 6 atp
krebs- 24
pyruvate- 6

Question 31

What hormone(s) triggers the action of glycogenesis and/or glycogenolysis

Answer 31

insulin

Question 32

Where does glycogen store in?

Answer 32

liver

Question 33

Glycogenesis – how does glucose become glycogen?

Answer 33

Glucose-1-P + UTP 🡪 UDP-glucose
Eventually these linkages of UDP-glucose becomes glycogen
Branching enzyme helps to branch up glycogen to increase storage efficiency and stability of glycogen

Question 34

How does glycogen breakdown into glucose??

Answer 34

The enzyme glycogen phosphorylase promotes glycogenesis, or the release of glucose into the blood. glycogen (+ glycogen phosphorylase) to glucose 6- phosphate
Glucose-6-phosphatase catalyzes hydrolytic release of Pi from glucose-6-P

Question 35

When blood glucose is low

Answer 35

glucagon

Question 36

When blood glucose is high

Answer 36

insulin

Question 37

What happen with excess glucose?

Answer 37

make glycogen or store as fat