Chapter 3- Carbs

Front 1

The majority of energy in the typical American diet comes from

Back 1

carbs

Front 2

a ketopentose is a carb containing

Back 2

5 carbons and a ketone group

Front 3

when compounds with 2 or more chiral carbon atoms and the same formulae are arranges as mirror images they are said to be

Back 3

asymmetrical

Front 4

name the model which depicts cyclized monosaccharides as lying in the horizontal plane with the hydroxyl groups pointing down or up from the plane

Back 4

Haworth

Front 5

which is the nutritional significance of stereoisomers?

Back 5

certain metabolic enzymes require a particular structure

Front 6

what are the major dietary energy sources that are composed of two simple sugars?

Back 6

disaccharides

Front 7

what is the most common digestible homopolysaccharide existing as both amylose and amylopectin?

Back 7

starch

Front 8

which of the following hemopolysaccharides made of glucose contributes the most energy to the ordinary diet?

Back 8

amylopectin

Front 9

in what form do carbs enter the bloodstream?

Back 9

monosaccharides

Front 10

what is the key in digestion of polysaccharides?

Back 10

a-amylase

Front 11

which of the following argon bonds is digested by a-amylase?

Back 11

a-1,4

Front 12

what is a likely reason that large quantities of fructose may cause gut discomfort?

Back 12

facilitated diffusion is slower than active transport

Front 13

which of the following i the predominant monosaccharide produced by the digestion of all dietary carbs?

Back 13

glucose

Front 14

the glucose transporter which is sensitive to insulin is

Back 14

GLUT4

Front 15

which hormonal changes occur in response to a fall in blood glucose concentration?

Back 15

decreased insulin, increased glucagon

Front 16

glycemic load considers the ___ in the food

Back 16

quantity and quality of carbohydrate

Front 17

due to a lack of the enzyme glucose 6-phosphatase, which tissue capable of glycogenesis cannot contribute to blood glucose levels between meals?

Back 17

muscle

Front 18

glycolysis is a process involvin

Back 18

reactions that concert glucose to pyruvate

Front 19

the major end products of cellular oxidation of carb include

Back 19

water, carbon dioxide, and energy

Front 20

in what part of the cell does glycol's occur

Back 20

cytoplasmic matrix

Front 21

in what organelle are the enzymes that catalyze the citric acid cycle located?

Back 21

mitochondrion

Front 22

in which cellular site is most of the energy released when carb are oxidized to carbon dioxide and water?

Back 22

mitochondrion

Front 23

under anaerobinx conditions within a cell, how many net ATPs are formed from one glucose molecule by substrate level phosphorylation?

Back 23

twoo

Front 24

in the complete oxidization of 1 mol of glucose, how many ATPs are formed?

Back 24

38

Front 25

when oxygen is present in a tissue, less glucose is metabolized to pyruvate, why?

Back 25

ATP accumulates and inhibits phosphotructokinase

Front 26

alcohol in beverages is degraded mainly in the liver cytoplasm with the production of one NADH for each ethanol molecule. predict what effect consumption of alcohol would have on the activity of the liver malate shuttle

Back 26

increased

Front 27

during the end reaction of the ETC, molecular oxygen becomes

Back 27

reduced to water

Front 28

electron flow through complexes 1, 111 and IV is accompanied by the translocation of protons

Back 28

from the matrix into the inter membrane space

Front 29

electrons carried by one mole NADH + H enter the electron transport chain at complex 1 and generate __ moles ATP as they are sequentially oxidized

Back 29

3

Front 30

the enzyme ATP synthase is believed to catalyze the formation of ATP according to the __ theory

Back 30

chemiosmotic

Front 31

the purpose of the hexose monophosphate shunt is to produce

Back 31

pentose phosphates and NADPH

Front 32

which tissue has the least activity of the hexose monophosphate shunt?

Back 32

skeletal muscle

Front 33

glyconeogenesis is essentially the reversal of which pathway?

Back 33

glycolysis

Front 34

all of the following are substrates for gluconeogenesis except

Back 34

fatty acids

Front 35

muscle lactate is converted to glucose in the liver and returned to the muscle by means of the

Back 35

cori cycle

Front 36

all of the following enzymes are negatively regulated by increasing levels of ATP except

Back 36

hexokinase

Front 37

if an individual with no blood sugar abnormalities when eating regularly presented with severe hypoglycaemia after 30 hours of fasting, which enzyme would you suspect might be malfunctioning?

Back 37

fructose 1, 6 biphosphatase

Front 38

glucagon stimulated hepatic glyconeogenesis and suppresses glycolysis by reducing the concentration of __, a positive modulator of phosphofructokinase

Back 38

fructose 2,6-biphosphate

Front 39

two hormones that stimulate glycogenolysis int he muscle and liver are

Back 39

epinephrine and glucagon

Front 40

a homopolysaccharide that is important in human diets is ___ and the end product formed from the complete digestion of this mono polysaccharide is

Back 40

starch; glucose

Front 41

T/F the purpose of the hexose monophosphate shunt (HMS) is to generate ribose, for nucleic acid synthesis , and NAD for oxidizing power.

Back 41

f. it generates NADH for reducing power

Front 42

T/F phosphorylation of a protein always results in its inactivation, whereas dphosphorylation activates it

Back 42

F. phsophorylation can sometimes inactivate a protein/enzyme and sometimes activate a protein/enzyme with dephospho rylation respectively activating and inactivating these enzymes

Front 43

T/F glucose is transported from the lumen into the enterocyte by active transport using SGLT1 protein which also required Na as a co-transporter

Back 43

True

Front 44

t/f the process of gluconeogenesis occurs partialy in the mitochondria and partially in the cytosol

Back 44

true

Front 45

t/f the muscle is an important tissue in gluceoneogenesis because it can use amino acids from protein breakdown and convert them to glucose, which it then secreted into the circulation for other tisues

Back 45

false

Front 46

t/f for lygoneolysis to occur, the signal in liver and muscle is glucagon, which si secreted but he pancreas in response to low blood glucose levels

Back 46

false

Front 47

t/f the reason we require the malate-aspartate shuttle is because NADH cannot enter the mitochondria to donate its electrons to the elevetron transport chain

Back 47

true

Front 48

t/f the core cycle would be active under anaerobic conditions, such as excessive muscle exertion

Back 48

true

Front 49

t/f although many enzymes in a given pathway are bidirectional, often the key enzymes are undirectional

Back 49

true

Front 50

t/f because they do not have mitochondria, red blood cels generate a lot of lactate from glycolysis, which they in turn must convert into glucose to meet their energy needs

Back 50

f

Front 51

t/f all cells have mitochondria, which act as the main site for ATP production

Back 51

false

Front 52

t/f active transport requires energy for the Na-K pump to transport Na out of the cell thereby driving the transport of something else, when the Na re-enters the cell own its concentration gradient

Back 52

true

Front 53

matcht the enzymes with the pathway in which they function in carb metabolism:

1 phosphofructokinase

2 pyruvate carboxylase

3 glycogen phosphrylase

4 glucose 6-phosphate dehydrogenase

5 branching enzyme

a glucogenesis

b glycolysis

c gluconeogenesis

d glycogenolysis

e hexose monophosphate shunt

Back 53

1 b

2 c

3 d

4 e

5 a

Front 54

a homopolysaccharide that is important in human diets is __ and the end product formed from the complete ingestion of this homopolysaccharide is __

Back 54

starch, glucose

Front 55

when dietary intake of carb is reduced or blood glucose concentration declines, the pathway that is stimulated in the liver by glucagon and corticosteroids is called ___. four non carb precursors that serve as substrates for this pathway are ___ ___ ___ ___ and amino acids

Back 55

gluconeogenesis, pyruvate, lactate, glycerol

Front 56

two hormones that stimulate glycogenolysis in the muscle and liver are __ and ___

Back 56

epinephrine, glucagon

Front 57

ADP can positively modulate the activity of the rate-limiting allosteric enzyme in glycolysis, __

Back 57

phosphofructokinase

Front 58

pyruvate dehydrogenase is positively modulated by ___ and ___

Back 58

AMP, NAD+

Front 59

all o the following are counter regulatory hormones except:

glucagon

insulin

cortisol

epinephrine

Back 59

insulin

Front 60

clinical hypoglycemia inclues adrenergic symptoms at about 60 mg/dL serum glucose. these symptoms include

Back 60

weakness, sweating, rapid heart rate, and tremor

Front 61

which of the following is true regarding hypoglycaemia?

Back 61

blood glucose levels and symptoms are not well correlated