Biochemistry - Carbohydrates

Front 1

Lactose: bond? enzyme? made of?

Back 1

lactase, beta 1-4, galactose and glucose

Front 2

Sucrose: bond? Enzyme? Made of?

Back 2

sucrase, alpha 1-2, glucose and fructose

Front 3

maltose and isomaltose: bond? Enzyme? Made of?

Back 3

maltose: alpha 1-4, maltase
isomaltose, alpha 1-6, isomaltase
- 2 glucose

Front 4

alpha endoglycosidases

Back 4

digests alpha 1-4 bonds

Front 5

what are disaccharides?

Back 5

lactose, sucrose and maltose

Front 6

bonds in amylose vs amylopectin

Back 6

amylose: alpha 1-4
amylopectin: alpha 1-6

Front 7

What is digested in the mouth? and by what? Broken down into what?

Back 7

Starch, salivary alpha amylase, a type of alpha-endoglycosidases, alpha dextrins, maltose and matotriose

Front 8

What digestion of carbohydrates in stomach?

Back 8

nothing!

Front 9

What does pancreatic alpha amylase act on? where is it released?

Back 9

alpha 1-4 bonds aka alpha dextrins, released in duodenum

Front 10

panreatic alpha amylase makes what?

Back 10

oligosaccharides, disaccharides (maltose and isomaltose) and trisaccharides

Front 11

Alpha glucosidases: breaks down what? found where? breaks down into?

Back 11

1) hydrolyze oligosaccharides, trisaccharides and disaccharides AT THE ENDS!
2) small intestine
3) glucose, monosaccharides

Front 12

What happens in the mucosal lining of the upper jejunum?

Back 12

final digestion, disaccharides attached to brush border and broken down by alpha glucosidases (isomaltase, maltase, etc)

Front 13

Where do undigested carbs go? What happens to them?

Back 13

into the colon, colon bacteria metabolizes saccharides via fermentation

Front 14

What do undigested carbs become?

Back 14

gas (H2, CO2,CH3), short chain fatty acids, lactate

Front 15

What happens to the gas from colon bacteria?

Back 15

they are osmotically active = increased retention of water in colon, water rushes into the lumen = diarrhea.
SYMPTOMS: diarrhea, bloating, bad breath

Front 16

A carbos?

Back 16

inhibits alpha glucosidase therefore glucose is not being broken down, treats type 2 diabetes mallitus

Front 17

Site of monosaccharide absorption

Back 17

duodenum, upper jejunum

Front 18

SGLT-1

Back 18

secondary active carrier, glucose, Na+/K+ pump creates Na+ gradient, and glucose goes against its gradient

Front 19

Glut 5

Back 19

- fructose, glucose, galactose

- sodium independent monosaccharide transporter

- facilitated diffusion

- intestinal epithelium and spermatazoa

Front 20

Glut 2

Back 20

- glucose, galactose, fructose

- liver and pancreatic beta cells, low affinity for glucose = functions at high concentrations of glucose

- works with glut 5 and SGLT 1

Front 21

GLUT 1

Back 21

red blood cells, all barriers (blood-brain, blood-retina, blood placental, blood testes), high affinity

Front 22

GLUT 3

Back 22

Brain, neurons, high affinity

Front 23

GLUT 4

Back 23

- adipose tissue, skeletal muscle, cardiac muscle

- insulin sensitive receptor; in presence of insulin, lots of receptors

- high affinity for glucose

Front 24

What is a cytoplasmic pathway?

Back 24

glycolysis

Front 25

anaerobic glycolysis

Back 25

pyruvate ---> lactate via lactate dehydrogenase (makes NADH into NAD+ to allow continuation of glycolysis)

Front 26

Hexokinase/Glucokinase Step

Back 26

Glucose to Glucose-6-Phosphate

- ATP to ADP

- irreversible

Front 27

Phosphofructokinase-1 Step

Back 27

Fructose-6-Phosphate to Fructose-1,6-bisphosphate

- Rate limiting enzyme

- irreversible

Front 28

Glyceraldehyde-3-Phosphate Dehydrogenase

Back 28

Glyceraldehyde-3-Phosphate to 1,3-bisphosphoglycerate

- oxidation reduction reaction

- arsenic metal ion competes with Pi here

Front 29

Phosphoglycerate Kinase

Back 29

1,3-bisphosphoglycerate to 3-Phosphoglycerate

- substrate level phosphorylation

Front 30

enolase

Back 30

2-Phosphoglycerate to Phosphoenolpyruvate

- bacterial enolate inhibited by fluoride

Front 31

Pyruvate Kinase

Back 31

Phosphoenolpyruvate to Pyruvate

- irreversible

- substrate level phosphorylation

- deficiency = hemolytic anemia

Front 32

Hexokinase

Back 32

- Km is 0.05mM

- low Vmax and low Km = high affinity

- substrates early

- active at low concentrations of glucose

- in cells other than liver and pancreatic beta

- allows for redistribution of glucose

Front 33

Glucokinase

Back 33

- Km is 5mM

- High Km, High Vmax

- Low affinity for glucose

- active at high concentrations of glucose

- in liver and pancreatic beta cells

- induced by insulin

Front 34

Maturity onset diabetes of the young (MODY)

Back 34

- type of type 2 diabetes

- mutation in pancreatic glucokinase

- Glut 2 uptakes glucose = Glucokinase engulfs it into G-6-P

- no glucokinase = no insulin released = lots of glucose in blood = hyperglycemia

- symptoms: polydipsia and polyuria

Front 35

PFK-1: inhibited by? stimulated by?

Back 35

- inhibited by: ATP, citrate

- stimulated by: AMP, Fructose-2,6-bisphosphate

- insulin stimulates, glucagon inhibits

Front 36

Arsenic Poisoning

Back 36

Glyceraldehyde-3-phosphate dehydrogenase, arsenic binds to organic phosphate, skips to 3-Phospholycerate and Net ATP is 0

Front 37

2,3-Bisphosphoglycerate

Back 37

binds to Hemoglobin A = decreases affinity for oxygen = allows release of oxygen, made from mutase from 1,3-bisphosphoglycerate,

Front 38

Enzymes induced by insulin and repressed by glucagon

Back 38

glucokinase, phosphofructokinase and pyruvate kinase

Front 39

pyruvate kinase and glucagon

Back 39

glucagon inhibits the enzyme =phosphorylates=inactive, activated by F-1,6-bp, inhibited by: ATP, acetyl co-A, alanine, long chain fatty acids,

Front 40

pyruvate transporter

Back 40

How pyruvate enters mitochondria

Front 41

pyruvate converted to acetyl coA

Back 41

- pyruvate dehydrogenase complex
- oxidative-decarboxylation

Front 42

Pyruvate Dehydrogenase complex

Back 42

- 5 enzymes:

Thiamine pyrophosphate (TPP)

Lipoate (lipoic acids)

NAD+ (niacin derivative)

FAD (riboflavin rerivative)

Reduced Coenzyme A (CoASH) (pantothenic acid derivative)

Front 43

What does arsenate bind to in the PDH complex?

Back 43

E2 - lipoate

Front 44

Aconitase

Back 44

- citrate to isocitrate

- fluoroacetate (rat poison) competes here

- fluoroacetyl coA + oxaloacetate = flurocitrate

Front 45

isocitrate deyhdrogenase

Back 45

- isocitrate to alpha-ketoglutarate

- rate limiting enzyme

- oxidative decarboxylation

Front 46

alpha-ketoglutarate dehydrogenase complex

Back 46

- alpha-ketoglutarate to succinyl coA

- oxidative decarboxylation

- similar to PDH complex

- succinyl coA has a high energy thioester bond

- coASH used here

Front 47

succinate thiokinase

Back 47

- Succinyl CoA to succinate

- substrate level phosphorylation

- GDP to GTP

- coASH exits

Front 48

succinate dehydrogenase

Back 48

- succinate to fumarate

- in the inner mitochondrial membrane

- complex 2!

- FAD to FADH2

Front 49

malate dehydrogenase

Back 49

malate to oxaloacetate

- regenerates oxaloacetate

Front 50

Net ATP from Anaerobic glycolysis

Back 50

2 ATP

Front 51

Net ATP from aerobic glycolysis

Back 51

7 ATP