EXAM #1: BIOCHEMISTRY OF THE GI TRACT Flashcards Preview

Gastrointestinal System > EXAM #1: BIOCHEMISTRY OF THE GI TRACT > Flashcards

Flashcards in EXAM #1: BIOCHEMISTRY OF THE GI TRACT Deck (66)
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1

What enzymes are contained in the mouth that begin the breakdown of food?

1) Alpha-amylase
2) Lingual lipase

2

What is the function of alpha-amylase?

Breakdown of starch in the mouth

3

What is the function of lingual lipase?

Breakdown of TAGs in the mouth

4

What macronutrient is NOT brokendown in the mouth?

Protein

5

What are the components of gastric juice that breakdown food?

1) HCl
2) Pepsin

6

What is the inactive zymogen form of pepsin?

Pepsinogen

7

What converts pepsinogen into its active form?

Secretion of HCl that lowers the pH of the gastric juice

8

What are the three functions of HCl in the stomach?

1) Initial breakdown of protein
2) Activation of pepsinogen to pepsin
3) Kill microorganisms

9

What enzymes are produced by the pancreas?

Amylase
Lipase
Peptidase

10

In addition to enzymes, what else does the pancreas secrete?

NaCl
NaHCO3

11

What pancreatic enzyme is secreted in its active form?

Pancreatic alpha-amylase

12

What is the function of bile acids?

Emulsificaiton of aggregated lipids to make them more accessible for lipid digestion enzymes

13

What form must carbohydrates be absorbed in in the small intestine?

Monosaccharide

14

What are the common sources of glucose?

Honey
Fruit
Corn syrup

15

What are the common sources of fructose?

Honey
Fruit

16

What is the common source of sucrose?

Table sugar

17

What is amylose?

Plant carbohydrate/ starch with alpha 1,4 glycosidic bonds

18

What is amylopectin?

Plant carbohydrate/starch with alpha 1,4 glycosidic bonds AND alpha 1,6 branches

19

What is the specific molecular function of alpha-amylase?

Hydrolysis of non-terminal alpha-1,4 linkages

20

What is the function of pancreatic alpha-amylase?

Conversion of branched polysaccharides into oligosaccharide units in the small intestine

21

What are the end products of pancreatic alpha-amylase digestion?

1) Maltose
2) Maltotriose
3) alpha-limit dextrins

22

What is cellulose? Why can't humans breakdown cellulose?

Polysaccharide plant cell wall component with BETA 1,4 GLYCOSIDIC BONDS

****Humans don't have BETA 1,4 ENDOGLYOCSIDASES to breakdown cellulose

23

What is Chitin? Why can't humans breakdown Chitin?

Polymer of N-acetyl-glucosamine with Beta 1,4 Glycosidic bonds that we do not have the enzymes to breakdown

****Comes from fungi and arthropods*****

24

How are the oligosaccharides made by alpha-amylase broken down into monosaccharides?

Membrane bound glycosidases on the luminal side of small intestine enterocytes

25

What is lactose hydrolyzed into via lactase?

1) Glucose
2) Galactose

26

What is maltose hydrolyzed into via maltase?

2x Glucose

27

What is sucrose hydrolyzed to via sucrase/isomaltase?

1) Glucose
2) Fructose

28

What transporter transports glucose across the membrane of the enterocyte for absorption?

Na+/Glucose cotransporter SGLT1

29

What transporter transports fructose across the enterocyte membrane for absorption?

Facilitated diffusion transporter, GLUT5

30

What is the role of Na+/K+ ATPase pumps in the absorption of monosaccharides?

- Cotransporters use Na+ as the driving force
- Concentration gradient is maintained by Na+/K+ ATPase