Carbohydrate Digestion Flashcards Preview

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Flashcards in Carbohydrate Digestion Deck (32):
1

True or false? Monosaccharides can be hydrolyzed into simple sugar

false; cannot

2

In regards to monosaccharides, ____ form stable ring structures in solution

hexoses

3

The cyclization of a monosaccharide introduces a new asymmetric carbon at carbon 1, which is known as a ____ carbon. This allows for ___ isomers called anomers

anomeric; 2

4

In regards to anomers, if the OH group is above the plane of ring, it is called ___ anomer, while if the OH group is below the plane of ring, it is called _____ anomer

beta; alpha

5

Anomeric-OH of one monosaccharide can react with another on a second monosaccharide, giving rise to a _____

glycosides

6

The linkage between monosacchardies is called _____ ____

glycosidic linkage

7

____ contains two alpha-D-glucose molecules linked together by alpha 1,4 glycosidic linkage

maltose

8

____ is formed by linking alpha-D-glucose with Beta-D-fructose to give a 1,2 glycosidic link

sucrose

9

____ is formed by joining Beta-D-galactose to alpha-D-glucose to give a Beta 1,4 glycoside

Lactose

10

This type of polysaccharide is made up of the same monosaccharide units: starch, glycogen, and cellulose

homopolysaccharides

11

This type of polysaccharide is made up of more than one kind of monosaccharide: condition sulfate, hyaluronic acid, and heparin

heteropolysaccharides

12

This type of polysaccharide is made of carbohydrates that are covalently attached to protein and lipid molecules: proteoglycans, glycoproteins, and glycolipids

glycoconjugates

13

This homopolysaccharide is a storage form of glucose and is found in plants. It is made of polymers of alpha linked glucose. There are 2 types: amylose (1,4) and amylopectin (1,4 and 1,6)

starch

14

This homopolysaccharide is a storage form of glucose in animals. It is more highly branched than amylopectin

glycogen

15

This homopolysaccharide is a chief constituent of plant cell walls. It is a liner homopolymer composed of Beta-D-glucose units linked by B-1,4 linkage. Animals lack the enzymes necessary to hydrolyze this linkage and can't digest this homopolysaccharide

cellulose

16

This is the most abundant heteropolysaccharide in the body. Hint: highly negative charged molecules

GAGs

17

This type of glycoconjugate is found in the extracellular matrix and consist of a GAG chain linked to a core protein

proteoglycan

18

What are some examples of glycoproteins (glycoconjugate)

antibodies, human blood group antigens, hormones FSH, LH, and TSH

19

Where are glycolipids present?

in nerve tissues (brain) and in cell membrane (gangliosides)

20

In regards to digestion of carbs, polysaccharides are broken down into monosaccharides (glucose, galactose) which are then absorbed by the intestinal lining by ____ diffusion. they are then transported through the venous system capillaries to the ___

facilitated; liver

21

Digestion requires what two enzymes?

1. amylase (salivary glands and pancreas)
2. oligosaccharidases (mucosal brush border enzymes)

22

For the following enzyme, give the activity, substrate, and product: maltase

activity: exoglucosidase alpha 1,4 only
substrate: malto-oligosaccharides
product: glucose

23

For the following enzyme, give the activity, substrate, and product: sucrase

activity: hydrolyzes sucrose and maltase activity
substrate: sucrose malto-oligosaccharides
product: glucose and fructose

24

For the following enzyme, give the activity, substrate, and product: isomaltase

activity: alpha 1,6 bonds
substrate: alpha-dextrins
product: glucose

25

For the following enzyme, give the activity, substrate, and product: lactase

activity: beta-glycosidase
substrate: lactose
product: glucose and galactose

26

For the following enzyme, give the activity, substrate, and product: trehalase

activity: trehalose
substrate: trehalose
product: glucose

27

Describe the process of absorption of monosaccharides

1. cotransport molecules in the brush border bind Na+ ions and glucose/galactose
2. Na+ ions pass into cell, down conc. gradient (facilitated diffusion)
3. Na+ ions are actively transported in exchange for K+ ions (active transport)
4. electrochemical gradient caused by active transport is used to transport glucose/galactose not cell against their conc. gradients
5. glucose/galactose moves out of other side of epithelial cell by facilitated diffusion

28

For the following Glucose transporter, give the location and characteristics: GLUT1

many tissues; basal transport, blood brain barrier

29

For the following Glucose transporter, give the location and characteristics: GLUT2

liver, islet B cells, kidney, small intestine; low affinity, high capacity

30

For the following Glucose transporter, give the location and characteristics: GLUT3

neurons; basal transport in neurons

31

For the following Glucose transporter, give the location and characteristics: GLUT4 (most important)

skeletal muscle, heart, and fat; insulin responsive transport

32

For the following Glucose transporter, give the location and characteristics: GLUT5

small intestine, sperm, testes; fructose transport