Deck 3: Carbohydrates

Question 1

Which disaccharide is commonly found in mushrooms?

A)glucose
B)fructose
C)trehalose
D)galactose

Answer 1

C

Question 2

A ketopentose is a carbohydrate containing ____.

A)five carbons and a ketone group
B)six carbons and an aldehyde group
C)three carbons and an aldehyde group
D)seven carbons and a ketone group

Answer 2

A

Question 3

What type of bond holds two monosaccharides together?

A)ionic
B)hydrogen
C)covalent
D)peptide

Answer 3

C

Question 4

Starches in the duodenum and jejunum are acted upon by ____.

A)β-amylase
B)lipase
C)sucrase
D)α-amylase

Question 5

The disaccharidases are synthesized by the ____.

A)pancreas
B)liver
C)enterocyte
D)chief cell

Question 6

The majority of energy in the typical American diet comes from ____.

A)fat
B)protein
C)carbohydrate
D)vitamins

Question 7

α-dextrinase is also called ____.

A)β-amylase
B)isomaltase
C)α-amylase
D)lactase

Question 8

Cellulose is a polymer of glucose where the monomers are connected by β-linkages. Humans cannot digest this substance because ____.

A)they only produce α-amylase
B)they produce insufficient quantities of β-amylase
C)cellulose is resistant to the human form of β-amylase
D)the β-linkages are too strong to be hydrolyzed

Question 9

Sucrose digestion is initiated in the ____.

A)pylorus
B)fundus
C)duodenum
D)mouth

Question 10

The enzyme needed to hydrolyze the α (1,6)bond of amylopectin is ____,which is secreted by the ____.

A)amylase; enterocyte
B)sucrose; pancreas
C)lactase; enterocyte
D)isomaltase; enterocyte

Question 11

Name the model that depicts cyclized monosaccharides as lying in a horizontal plane with the hydroxyl groups pointing down or up from the plane.

A)Haworth
B)Fischer projection
C)cyclized Fischer projection
D)stereoisomer

Question 12

Choose the best description of the main method of glucose absorption.

A)passive diffusion down a concentration gradient
B)active transport with fructose
C)facilitated transport
D)active transport with sodium

Question 13

A homopolysaccharide that is important in human diets is ____ and the end product formed from the complete digestion of this homopolysaccharide is ____.

A)cellulose; glucose
B)lactose; galactose
C)glycogen; glucose
D)starch; glucose

Question 14

What is the key enzyme in digestion of polysaccharides?

A)starch amylopectin
B)β-amylase
C)α-dextranase
D)α-amylase

Question 15

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

A)disaccharides
B)polysaccharides
C)monosaccharides
D)trioses

Question 16

Chiral carbon atoms have ____.

A)four hydrogens attached to them
B)two methyl groups and two hydrogens attached to them
C)three hydrogen atoms and one methyl group attached to them
D)four different atoms or groups attached to them

Question 17

Which sugar is not present in the systemic circulation due to efficient removal by the liver?

A)glucose
B)fructose
C)galactose
D)sucrose

Question 18

Which of the following homopolysaccharides made of glucose contributes the most energy to the ordinary diet?

A)amylose
B)amylopectin
C)glycogen
D)cellulose

Question 19

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

A)glycogen
B)cellulose
C)hemicellulose
D)starch

Question 20

When compounds with one or more chiral carbon atoms and the same formula are arranged as mirror images they are said to be ____.

A)symmetrical
B)enantiomers
C)rotated
D)linear

Question 21

In the ____,galactose is eventually converted to ____.

A)liver; glucose
B)Kupffer cell; fructose
C)small intestine; glucose
D)chylomicron; glucose

Question 22

The poison,sodium cyanide,inhibits the enzyme cytochrome c oxidase.Why is ingestion of this poison usually fatal?

A)It blocks the production of ATP in the cells.
B)It causes cells to rupture.
C)It changes membrane permeability allowing important molecules to leave the cell.
D)It causes changes in the acetyl-coenzyme A molecule.

Question 23

In the complete oxidation of 1 mol of glucose,how many ATPs are formed?

A)4-6
B)8-12
C)18-24
D)30-32

Question 24

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

A)increased insulin, decreased glucagon
B)decreased insulin, increased glucagon
C)decreased insulin, decreased glucocorticoids
D)increased insulin, increased glucagon

Question 25

Two hormones that stimulate glycogenolysis in the muscle and liver,respectively,are ____.

A)cortisol and epinephrine
B)epinephrine and glucagon
C)insulin and epinephrine
D)glucagon and insulin

Question 26

Which substance is converted into glycogen in the process of glycogenesis?

A)2-phosphoglycerate
B)glucose-1-phosphate
C)fructose-1-phosphate
D)phosphoglyceraldehyde

Question 27

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

A)cytoplast
B)endothelium
C)Golgi body
D)mitochondrion

Question 28

The conversion of pyruvate to oxaloacetate in gluconeogenesis allows which molecules to enter the gluconeogenic pathway?

A)alcohols
B)amino acids
C)monosaccharides
D)polysaccharides

Question 29

The glucose transporter that is sensitive to insulin is ____.

A)GLUT1
B)GLUT2
C)GLUT4
D)SGLT1

Question 30

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

A)liver
B)muscle
C)brain
D)kidney

Question 31

Glycolysis is a process involving ____.

A)synthesis of fatty acids
B)reactions that convert glucose to glycogen
C)reactions that convert glucose to pyruvate
D)reactions that convert glycogen to protein

Question 32

Which process produces glucose-6-phosphate from noncarbohydrate sources?

A)glycolysis
B)glycogenolysis
C)glycogenesis
D)gluconeogenesis

Question 33

Glycemic load considers the ____ in the food.

A)protein and carbohydrate content
B)fat and carbohydrate content
C)fat to carbohydrate ratio
D)quantity and quality of carbohydrate

Question 34

Insulin is an anabolic hormone.Which process does insulin stimulate?

A)lipolysis
B)gluconeogenesis
C)glycogenesis
D)ketogenesis

Question 35

Glucose phosphorylation in the liver is catalyzed by ____.

A)glucokinase
B)hexokinase
C)insulin
D)glucagon

Question 36

People with type 1 diabetes have ____.

A)slow translocation of GLUT4 receptors from the Golgi body
B)lack of mRNA synthesis for GLUT4 receptors in adipocytes or myocytes
C)increased glycogenesis in myocytes after a meal
D)below-normal glucokinase activity because of low insulin levels

Question 37

Conversion of phosphorylase b to the active phosphorylase a is carried out by ____.

A)ADP
B)AMP
C)ATP
D)cAMP

Question 38

Where are the enzymes that catalyze the citric acid cycle located?

A)cytoplasmic matrix
B)endoplasmic reticulum
C)mitochondrial matrix
D)lysosome

Question 39

In what part of the cell does glycolysis occur?

A)mitochondrion
B)cytosol
C)nucleus
D)endoplasmic reticulum

Question 40

Alcohol in beverages is degraded mainly in the liver cytosol 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-aspartate shuttle.

A)no change
B)increased
C)decreased
D)reversed

Question 41

The purpose of the pentose phosphate pathway is to generate ribose,for nucleic acid synthesis,and NAD,for oxidizing power.

Question 42

Which tissue has the least activity of the pentose phosphate pathway?

A)liver
B)adrenal cortex
C)mammary gland
D)skeletal muscle

Question 43

The Cori cycle would be active under anaerobic conditions,such as excessive muscle exertion.

Question 44

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

A)phosphofructokinase
B)pyruvate kinase
C)fructose-1,6-bisphosphatase
D)glucose-6-phosphatase

Question 45

Glucose is transported from the lumen into the enterocyte by active transport using SGLT1 protein,which also requires Na as a co-transporter.

Question 46

The purpose of the hexose monophosphate shunt is to produce ____.

A)pentose phosphates and NADPH
B)DNA and RNA
C)fatty acids
D)reducing substrates

Question 47

The occurrence of a molecule in different spatial configurations is ____.

A)isotopism
B)isomerism
C)stereoisomerism
D)rotationalism

Question 48

The muscle is an important tissue in gluconeogenesis because it can use amino acids from protein breakdown and convert them to glucose,which it then secretes into the circulation for other tissues.

Question 49

The process of gluconeogenesis occurs mainly in the liver and,in cases of starvation,in the kidneys as well.

Question 50

Pentose sugars provide more dietary energy than hexose sugars.

Question 51

All of the following are substrates for gluconeogenesis EXCEPT ____.

A)fatty acids
B)lactate
C)glycerol
D)glucogenic amino acids

Question 52

In skeletal muscle,hypercortisolism may lead to ____.

A)enlargement of muscle fibers
B)reduction in the size of muscle fibers
C)increased contractile strength of muscle fibers
D)increased healing capability

Question 53

The abundance of GLUT4 is increased by induction in response to a high-CHO meal.

Question 54

Gluconeogenesis is essentially the reversal of which pathway?

A)glycogenesis
B)glycolysis
C)TCA cycle
D)glycogenolysis

Question 55

Glucose phosphorylation in the liver is catalyzed by glucokinase.

Question 56

The enzyme ATP synthase is believed to catalyze the formation of ATP,as described by the ____ theory.

A)leakage
B)hydrogen pump
C)protein channel
D)chemiosmotic

Question 57

Glycogenolysis in muscle cells provides glucose that can be transported through the bloodstream.

Question 58

Enterocytes absorb only one form of carbohydrate.This form is ____.

A)disaccharides
B)polysaccharides
C)monosaccharides
D)trisaccharides

Question 59

Glucagon,epinephrine,and norepinephrine enhance the regulation of ____.

A)glucose-1-phosphate
B)phosphorylase
C)coenzyme Q
D)phosphofructokinase

Question 60

During the end reaction of the electron transport chain,molecular oxygen becomes ____.

A)oxidized to carbon dioxide
B)reduced to water
C)NADH + H+
D)FADH₂

Question 61

Match the enzymes with the pathway in which they function in carbohydrate metabolism.
a.glycogenesis
b.glycolysis
c.gluconeogenesis
d.glycogenolysis
e.pentose phosphate pathway
phosphofructokinase

Question 62

Match the enzymes with the pathway in which they function in carbohydrate metabolism.
a.glycogenesis
b.glycolysis
c.gluconeogenesis
d.glycogenolysis
e.pentose phosphate pathway
pyruvate carboxylase

Question 63

A number of metabolic pathways have a problem in that certain components required for them to function are found in either the cytosol or the mitochondria,and some intermediates cannot cross the membrane.This requires that certain compounds be shuttled from one compartment to the other.Explain this shuttling process for either: (a)glycolysis/TCA cycle OR (b)gluconeogenesis.Your answer should include what needs to be shuttled,why it needs to be shuttled,and how this is accomplished.

Question 64

Match the transporter proteins with their major site of expression.
a.erythrocytes,CNS
b.liver,β-cells,kidney
c.brain,sperm,placenta
d.muscle,heart,adipocytes
e.intestine,kidney,brain,skeletal muscle,adipose
GLUT2

Question 65

Active transport requires energy for the Na-K pump to transport Na out of the cell,thereby driving the transport of another substance (e.g.,glucose)when the Na re-enters the cell down its concentration gradient.

Question 66

Match the transporter proteins with their major site of expression.
a.erythrocytes,CNS
b.liver,β-cells,kidney
c.brain,sperm,placenta
d.muscle,heart,adipocytes
e.intestine,kidney,brain,skeletal muscle,adipose
GLUT1

Question 67

Match the enzymes with the pathway in which they function in carbohydrate metabolism.
a.glycogenesis
b.glycolysis
c.gluconeogenesis
d.glycogenolysis
e.pentose phosphate pathway
glucose-6-phosphate dehydrogenase

Question 68

Because they do not have mitochondria,red blood cells generate a lot of lactate from glycolysis,which they in turn must convert into glucose to meet their energy needs.

Question 69

Match the enzymes with the pathway in which they function in carbohydrate metabolism.
a.glycogenesis
b.glycolysis
c.gluconeogenesis
d.glycogenolysis
e.pentose phosphate pathway
glycogen phosphorylase

Question 70

Match the enzymes with the pathway in which they function in carbohydrate metabolism.
a.glycogenesis
b.glycolysis
c.gluconeogenesis
d.glycogenolysis
e.pentose phosphate pathway
branching enzyme

Question 71

Fructose transport into the enterocyte relies on the facilitative transporter GLUT5.

Question 72

Glycogenesis,glycogenolysis,gluconeogenesis,and glycolysis are tissue-specific-that is,either the pathway or certain aspects of the pathway are different for different tissues.Pick ONE metabolic process and describe what occurs,including what tissues are involved and any tissue-specific differences.Make sure to indicate any and all signals involved in this process.

Question 73

Often you will hear the statement,"Insulin is important for the uptake of blood glucose by all tissues." What is wrong with this statement? Be specific.

Question 74

Match the transporter proteins with their major site of expression.
a.erythrocytes,CNS
b.liver,β-cells,kidney
c.brain,sperm,placenta
d.muscle,heart,adipocytes
e.intestine,kidney,brain,skeletal muscle,adipose
GLUT4

Question 75

Match the transporter proteins with their major site of expression.
a.erythrocytes,CNS
b.liver,β-cells,kidney
c.brain,sperm,placenta
d.muscle,heart,adipocytes
e.intestine,kidney,brain,skeletal muscle,adipose
GLUT5

Question 76

Match the transporter proteins with their major site of expression.
a.erythrocytes,CNS
b.liver,β-cells,kidney
c.brain,sperm,placenta
d.muscle,heart,adipocytes
e.intestine,kidney,brain,skeletal muscle,adipose
GLUT3

Question 77

All cells have mitochondria,which act as the main site for ATP production.

Question 78

Maintenance of normal blood glucose concentration is controlled by the small intestine,the liver,the kidneys,skeletal muscle,and adipose tissue.

Question 79

After hydrolysis of triacylglycerols stored in adipose tissue,free glycerol in the blood is converted in the liver to glucose via glycogenolysis.

Question 80

Enzymes are regulated by induction,covalent regulation (a form of posttranslational modification),and allosteric modification.Pick out any THREE (3)enzymes from the enzymes involved in glycolysis,the TCA cycle,gluconeogenesis,glycogenesis,or glycogenolysis.Then,indicate: the reaction that the enzyme catalyzes; what tissue(s)this occurs in; how it is regulated (via one of the mechanisms listed above); and what signals are involved in its regulation.NOTE: Long answers are unnecessary-this can be done in a relatively short single sentence.