9 21 Nutrient digestion and absorption 1-Table 1 Flashcards Preview

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Flashcards in 9 21 Nutrient digestion and absorption 1-Table 1 Deck (65):
1

what are the common maronutrients found in a "western" dite.

Carbohydrates (polysaccharides, Disaccharides, monosaccharides); Proteins; Fats (Triacylglycerol, phospholipids; cholesterol).

2

Carbs that can not be digested by human enzymes -- exemplified by a beta sugar configuration.

Dietary Fiber

3

describe how carbs are digested/absorbed

Mouth(Amylase); Duodenum (Pancreatic amylase); Small intestine (Maltase, Sucrase, Lactase). Break the carbohydrates down to monosacharides.

4

explain lactose intolerance

70% of population Hypolactasia; don't absorb lactase, lactase will get absorbed and digested by the gut bacteria.

5

explain fructose malabsorption.

GLUT 5 mutation could lead to inability to inability to absorb Fructose.

6

average amount of this macromolecule in western diet is 300 g/day

Carbohyderates

7

what are the constituents of a carbohyderate?

polysaccharides (starch, glycogen); disaccharides (sucrose, lactose, maltose); monosaccharides (fructose, glucose, galactose);; non-digestible carbs (fiber)

8

polysaccharides

starch (65%)/ glycogen (.0%)

9

what is starch

glucose linked together, mostly linear, some branches. (flour, corn, potatoes)

10

Disaccharides

sucrose(25%) lactose (6%); maltose

11

what is sucrose

Glucose -alpha(1,2)-Fructose

12

what is lactose

Galactose-beta(1,4)-glucose

13

what fructose

fruit sugar,, and the monomer of sucrose.

14

Monosaccharides

fructose,glucose (3%) and galactose

15

non-digestible carbs

fiber!

16

Amount of proteins in day avg.

100g/day

17

where do we get glycogen?

meat!

18

amount of fats in day?

80g/day triclyglycerol;phospholipids'cholesterol

19

what are the three components of fats?

triachyglycerol; phospholipids'; cholesterol

20

what is starch?

mostly unbranched amylose linked alpha 1,4: plus some occasionally branched amylopectin linked alpha 1,6;

21

what is sucrose?

glucose with alpha 1,2 link to fructose

22

what is lactose?

galactose beta 1,4 link to glucose

23

so what links do we break to break starch?

alpha 1,4, and some alpha 1,6

24

what is digestion in general

the way that we break polymers to monomers

25

carbohyderate digestion and absorption summary!

h (picture on slide 9)

26

what is the first digestive enzyme?

salivary amylase

27

describe the basic path of digestion

salivary amylase; pancreatic amylase; maltase;surase,lactase.

28

pancreatic amylase

breaks long chains of the startch to disacerides

29

what does maltase do?

breaks matose to glucose molecules (2 of them)

30

they break the disacherides to monosacherides

what is a disacherideases

31

what does sucrase do?

they breack sucrose to glucose and fructose

32

what does lactase do?

break lactose to glucose and galactose.

33

what are the monomers that can be absorbed?

glucose, fructose, galactose, and D-Xylose

34

why is the small intestine not at pH 2 like the stomach

secrete bicarbonate in the small intestine to buffer back to around 7 pH

35

moves glucose and gallactose into the epitheilial

SGLT1 (Na cotransporter)

36

moves glucose and galactose into the epithelial cell when eat alot of sugars

GLUT2

37

move the fructose down its concentration gradient into the epithelial cells

GLUT 5

38

move glucoes fructoes and galactose from the epithelial to the interstitial space

GLUT2

39

that is in table sugar?

Sucrose or (glucose -alpha 1,2 bound to frutose)

40

corn syrup

mostly glucose, some maltose and isomaltose (hydrolyzed corn starch

41

high fructose corn syrup

corn syrup processed to convert 50% of glucose to fructose

42

Honey

82% carbohydrate. (38% fructose 31% glucose, 13% di and oligosaccharides)

43

agave syrup

55%-90% fructose, remainder of carbohydrate is mostly glucose.

44

under what condition might cane sugar and highfructose corn syrup affect the body differently?

you need a disaccharidase to hydrolize this (sucrase). (it is about the same as table sugar). If sucrase is the rate limiting step, then there will be a difference between high fructose corn syrup and sugar (there doesn't seem to be much evidence for this. Therefore it really doesn't matter that much.

45

why change glucose to fructose

fructose tastes sweeter than glucose

46

how do we effectively get all digested macronutrients absorbed?

about 9000 m2 surfacd area in the villi and microvilli

47

what transporter is likely to cause fructose malabsorption?

GLUT 5

48

what could lead to bloating, intestinal cramps and gas after the consumption of pizza and ice-cream

lactose intolerance! not enough lactase! don't break down lactose (milk sugar), but the gut bacteria aborb it and emit a lot of gas!

49

what does lactase do?

break lactose into the monomers galactose and glucose

50

what is hypolactasia

it is a lack of lactase in the brush border microvilli

51

what percent of people are hypolactaseic?

70% of people.

52

what happens to the blood glucose of a hypolactasia person when consume milk?

it goes up a tiny part

53

what happens to the blood glucose of a non-hypolactasia person when consume milk?

it spikes why up!

54

how is the blood glucose different after absorbing milk? (for hypolactasia/ normal)

normal would spike and hypolactasia would not!

55

after lactose consumption: why blood sugar spike for "normal" and why H2 spike fore "hypolactasia"

the blood sugar goes up as lactate broken down and H2 is from bacterial metabolism

56

compare the mean breath H2 for hypolactasia vs. non-hypolactasia ("normal")

the breath pH would spike for hypolactasia and pretty flat for "normal"

57

what is the difference in a alpha vs. a beta sugar conformations

the OH of the #1 carbon is oriented "down" on an alpha glucose, and "up" on a beta glucose. (in reference to the carboxy group on the #6 carbon.

58

why do you get diarrhea with a lactose intolerance?

extra lactase not absorbed and raises the osmolarity of the intestines

59

why do we care if the sugar is oriented alpha or beta?

digestive enzymes are specific for either the alpha or the beta configuration.

60

what is digestible vs. non digestible fiber?

insoluble fiber has only the beta 1,4! and soluble fiber has some beta 1,3 (looks like an alpha bond)

61

what is dextrose/

Glucose! (D-Glucose)

62

Soluble fiber?

gummy, viscous. digeste/partially metabolized by intestinal bacteria. binds cholesterol and inhibits its absorption

63

insoluble fiber

richer in wheat bran. prevent constipation, possibly diverticular disease.

64

what type of enzymatic activity is most likely responsible for beano's effectiveness?

probably an alpha galactosidase to break the alpha bond between the galactose and glucose and galactose and galactose molecules found in the carbs in beans.

65

what happens when you can't fully digest carbs?

excessive colonic bacterial fermentation: gas, bloating, discomfort, and diarrhea (osmotic diarrhea).