GI

Question 1

2 types of cellular pathways?

Answer 1

• Catabolic.
• Anabolic.

Question 2

What are carbohydrates?

Answer 2

• Organic molecules containing CHO.
• Monosaccharides: smallest like glucose cannot be further hydrolysed.
• Disaccharide: Two monosaccharides joined by glycosidic chain.
• Oligosaccharide: A few (3-10).
• Polysaccharide: More than 10.

Question 3

Normal cells produce how many ATP in glycolysis?

Answer 3

38.

Question 4

Cancer cells produce how many ATP in glycolysis?

Answer 4

2.

Question 5

What happens in stomach?

Answer 5

Site of minimal digestion.
Amylase in saliva.

Question 6

What happens in intestinal mucosa?

Answer 6

Carbs—-> Disaccharide or trisaccharide (amylases).

Question 7

What happens in oral cavity?

Answer 7

Carbs—-> Disaccharide or trisaccharide (pancreatic amylases).

Question 8

What happens in small intestine?

Answer 8

Di/trisaccharide to monosaccharide.
These are all absorbed into gut epithelial cells.

Question 9

What happens to dietary glucose?

Answer 9

Glucose leaves intestine via hepatic portal vein and arrives first at the liver. Hepatocytes take up glucose where it is converted to pyruvate in the cytoplasm.

Question 10

What does glycolysis mean?

Answer 10

The conversion of glucose to pyruvate in cytoplasm.

Question 11

Glucolysis 10 step pathway?

Answer 11

1. Conversion glucose to glucose 6 phosphate.
2. Glucose 6 phosphate to fructose 6.
3. Fructose 6 to fructose 1,6 biphosphate.
4. Fructose 1,6 bi to glyceraldehyde 3 and dihydroxyacetone phosphate.
5. Dihydro to gllyceraldgeyde 3.
6. Glucealdehyde 4 to 1,3 bi.
7. 1,3 bi to 3 phosphoglycertae.
8. 3-phospho to 2 phospho.
9. 2 phospho to phospho.
10. Phospho to pyruvate.

Question 12

Protein analysis technique is called?

Answer 12

X ray crystallography.
Can be used to generate quaternary structures.

Question 13

Formation of acetylene coA.

Answer 13

Stage 1- Generation of an activated 2 carbon fragment.
Acetyl co A cell can use different fuels other than glucose (can use amino acids fatty acids).

Question 14

Pyruvate oxidation first involves its movement across mitochondrial membrane by the pyruvate carrier.

Question 15

Stomach stores and emulsifies?

Answer 15

Fatty food.
Gradually transferred to duodenum.

Question 16

Minimal digestion by?

Answer 16

Lipases in saliva.

Question 17

Small intestine?

Answer 17

Lipases break fat into free fatty acids that are absorbed by the gut epithelial cells where they resynthsised into triglycerils.

Question 18

Bile salts?

Answer 18

Detergent substance.
Emulsify fat. Allows enzymes to digest fat.

Question 19

Lipid and proteins become soluble. These are called?

Answer 19

Lipoproteins.

Question 20

Products of lipid digestion?

Answer 20

Glycerol, free fatty acids, monoacylglycerols, diaclycerols.

Question 21

Saturated fatty acids are?

Answer 21

Simplest form of lipid.
Saturated= no carbon double bonds.

Question 22

Terminal carboxyl group?

Answer 22

Affinity to water when ionised.

Question 23

Unsaturated fatty acids?

Answer 23

Some carbon double bonds present.

Question 24

Examples of acids?

Answer 24

• Stearic acid- Saturated.
• Oleic acid- Mono unsaturated.
• Linoleic acid- Poly unsaturated fatty acid.

Question 25

Major components of dietary fat are?

Answer 25

Triaclyglycerol ( Triglyceride). Cholesterol.

Question 26

Lipid digestion?

Answer 26

- Lipase in saliva and in small intestine break triaglycerol into glycerol and 3 fatty acids. - Short are absorbed directly into blood stream form gut epithelial cells and transported to liver attached to albumin. - Longer chain fatty acids and those still attached to glycerol taken up into ER.

Question 27

Fatty acids ————> Acetyl coA. B Oxidation pathway

Question 28

B oxidation of fatty acids?

Answer 28

Transport of long fatty acids into mitochondria.

Question 29

B oxidation fatty acids with odd number carbon?

Answer 29

- Carboxylation- absolute requirement of biotin as co enzyme a. - conversion of D isomer to L isomer. - Syntheiss of succinyl COA. - Succinyl CoA enters citric acid cycle directly.

Question 30

Oxidation of 2 carbons in acetylene CoA.

Answer 30

In citric acid cycle to form 1 GTP and 2 CO2 and 4 pairs of electrons.

Question 31

Electron transport chain?

Answer 31

Folded into projections called cristae.

Question 32

Storage of excess glucose?

Answer 32

Glycogen stored mainly in liver. Glycogen synthesis requires energy.

Question 33

Fatty acid synthesis occurs in?

Answer 33

Cytosol.

Question 34

Fatty acids synthesis from?

Answer 34

Acetyl CoA.

Question 35

What’s produces as an end product?

Answer 35

Palmitate (C16).

Question 36

Production of Acetyl CoA in matrix of mitochondrion is first stage of fatty acid biosynthesis. Citrate translocated into cytosol when mitochondrial conc is too high.

Question 37

Step 2: is Carboxykation of Acetyl CoA to malonyl CoA.

Question 38

Fatty acid synthase- a multifunctional enzyme.

Question 39

Liver exports TAGs packaged with other lipids to form?

Answer 39

Very low density lipoproteins.

Question 40

Fat more energy release than carbs. Denser than carbs. Most energy in fat released as oxidation of fatty acids for many tissues (except brain).

Question 41

Lipolysis?

Answer 41

Achieved by lipases. - Adipose triglyceride. - Hormone sensitive. - Monoacylglycerol.

Question 42

Fate of glycerol?

Answer 42

Blood to liver, phosphorykated to glycerol 3 phosphate to form new TAGs.

Question 43

Fate of fatty acids?

Answer 43

Bind to albumin, transported to tissues cells, activated into coA derivatives, oxidised in mitochondria.