Intro to carbs (1)

Question 1

In a D sugar, how would you distinguish an alpha anomer or beta anomer?

Answer 1

alpha - OH is opposite to CH2OH
–starts down

Beta - OH is in same direction as CH2OH
-starts up

Question 2

What is:

1. disaccharide
2. oligosaccharide
3. polysaccharide

Answer 2

1. 2 sugars covalently bound
2. 2-15 sugars covalently bound
3. many sugars covalently bound

Question 3

What is amylose?

Answer 3

a starch with alpha 1,4 linkages

Question 4

What is amylopectin?

Answer 4

a startch wtih alpha 1,4 linkages

alpha 1,6 branches

Question 5

What is lactose?

Answer 5

galactose bound to glucose

B 1,4 linkages

Question 6

What is sucrose?

Answer 6

alpha 1,2 glucose to fructose
(hexagonal cyclic structure = fructose)
-table sugar
-non-reducing sugar because OH’s of two anomeric Cs are not free

Question 7

What is the structure of glycogen?

Answer 7

identical to amylopectin, but has a bit more branching

Question 8

Define:

1. endoglycosidases
2. exoglycosidases
3. disacharidases

Answer 8

1. cleaves internal glycosidic bonds
2. cleaves terminal glycosidic bonds
3. cleaves glycosidic bonds in disaccharides

Question 9

What is alpha-amylase?

Answer 9

cleaves Glu-alpha 1,4-Glu

-endoglycosidase

Question 10

What is glucoamylase?

Answer 10

cleaves Glu-alpha 1,4-Glu

-exoglycosidase

Question 11

What is maltase?

Answer 11

cleaves Glu-alpha 1,4- Glu

-disacharidase (and some larger)

Question 12

What is isomaltase?

Answer 12

cleaves Glu-alpha 1,6-Glu

-disacharidase (and some larger)

Question 13

What is lactase?

Answer 13

cleaves Gal-B1,4-Glu

-disacharidase

Question 14

What is sucrase?

Answer 14

cleaves Glu-alpha 1,2 -Fru

-disaccharidase

Question 15

What is cellulose?

Answer 15

linear polysaccharide
starch with B1,4 linkages
-CANT be digested by humans

Question 16

What is the function of salivary amylase?

Answer 16

cleaves starch polymers into smaller polysacharides

-inactivated by acid in the stomach

Question 17

What is the function of pancreatic alpha-amylase? What products does it produce?

Answer 17

continues hydrolyzing starch digestion 
Produces:
-maltose
-maltotriose
-longer linear oligosacccharides
-alpha-dextrins
-isomaltose

Question 18

Where does the digestion of oligos and disaccs to monos take place?

Answer 18

glycosidases that are attached to the brush border

in the jejunum

Question 19

What are the glycosidases at the brush border? (5)

Answer 19

1. glucoamylase
2. maltase
3. isomaltase
4. sucrase
5. lactase

Question 20

What does the severity of lactase intolerance symptoms depend on?

Answer 20

ethnicity, age, speed of digestion

Question 21

Glucose is the exclusive fuel of:

Answer 21

RBCs

Question 22

What is the function of glycolysis?

Answer 22

produce pyruvate and ATP

• in all cells
• cells with mitochondria and O2–> combo with CAC

Question 23

Where does the conversion of glucose into glycogen take place?

Answer 23

liver and muscle

Question 24

What is the function of the pentose phosphate pathway?

Answer 24

generates NADPH

-critical for making fatty acids

Question 25

What is “breakdown of glycogen to glucose”

Answer 25

glycogenolysis

Question 26

What is” synthesis of glucose from non-carb sources such as AAs”

Answer 26

gluconeogenesis

Question 27

What are the three effects of glucagon release ?

Answer 27

mobilize fuels to inc blood glucose

1. inc glycogen breakdown in liver
2. inc gluconeogenesis in liver
3. inc lipolysis in adipose tissue

Question 28

What are the three functions of insulin?

Answer 28

promotes fuel storage:

1. increases glycogen synthesis in liver & muscle
2. inc fatty acid synthesis in the liver
3. inc triglyceride synthesis