ANSC 3400 Exam 2 Review

Which of the following sugars is a hexose monosaccharide?

Galactose

What volatile fatty acid is used to make glucose in the ruminant liver?

 

Propionic acid

What is not an example of a carbohydrate?

Lignin

Which of the following sugars is not a hexose monosaccharide?

Ribose

What best describes hemicellulose?

 

Branched polysaccharide; cross-links cellulose microfibrils

What animal enzyme hydrolyzes the α-1,6 glycosidic bond between two D-glucose molecules?

Isomaltase

What is an important function of the pentose phosphate pathway?

 

NADPH production

What electron carrier must be regenerated during anaerobic fermentation of glucose to volatile fatty acids?

 

NAD+

What is the correct sequence for the enzymatic digestion of amylose in non-ruminant animals?

 

Amylose → maltose → glucose

Which of the three major volatile fatty acids that are produced from carbohydrate fermentation in the rumen is produced in the least amount?

 

Butyric acid

What is the major milk sugar produced in the mammary gland?

Lactose

What is the correct sequence for the enzymatic digestion of amylopectin in non-ruminant animals?

 

Amylopectin → maltodextrin → maltose + isomaltose → glucose

What animal enzyme hydrolyzes the α-1, β-2 glycosidic bond between D-glucose and D-fructose?

Sucrase

What is the link reaction for the enzyme “Hexokinase”

Glucose + ATP→Glucose-6-phosphate + ADP; first step in glycolysis

What is the link reaction for the enzyme “Phosphofructokinase-1”

Fructose-6-phosphate + ATP→ Fructose-1,6-biphosphate + ADP; rate limiting (slowest) step in glycolysis

What is the link reaction for the enzyme “Pyruvate Kinase”

Phosphoenolpyruvate +ADP→Pyruvate +ATP; last step in glycolysis

What is the link reaction for the enzyme “Pyruvate Dehydrogenase complex”

Pyruvate +Coa-SH + NAD+ → Acetyl CoA +CO2 +NADH; links glycolysis to the citric acid cycle

Is glucose a monosaccharide, disaccharide, or polysaccharide?

Monosaccharide, non structural carbohydrates

Is sucrose a monosaccharide, disaccharide, or polysaccharide?

Disaccharide; non-structural carbohydrate

Is Maltose a monosaccharide, disaccharide, or polysaccharide?

Disaccharide; non-structural carbohydrate

Is cellulose a monosaccharide, disaccharide, or polysaccharide?

Polysaccharide; structural carbohydrate

Is pectin a monosaccharide, disaccharide, or polysaccharide?

Polysaccharide; structural carbohydrate

Is amylopectin a monosaccharide, disaccharide, or polysaccharide?

Polysaccharide; non-structural carbohydrate

Is fructose a monosaccharide, disaccharide, or polysaccharide?

Monosaccharide; non-structural carbohydrate

Is amylose a monosaccharide, disaccharide, or polysaccharide?

Polysaccharide; non-structural carbohydrate

Is hemicellulose a monosaccharide, disaccharide, oligosaccharide or polysaccharide?

Polysaccharide; structural carbohydrate

Is maltodextrin a monosaccharide, disaccharide, or polysaccharide?

Oligosaccharide; non-structural carbohydrate

What factor does not contribute to structural carbohydrate degradation in the rumen?

 

Salivary amylase activity

What volatile fatty acid more when ruminants are fed high roughage, slowly fermentable diets?

 

Acetic acid

How does the horse differ from other non-ruminant livestock animals with respect to carbohydrate digestion?

 

Significant structural carbohydrate degradation and volatile fatty acid production in the hindgut

What is the correct sequence for the enzymatic digestion of cellulose in non-ruminant animals?

 

Cellulose is not digested by non-ruminant animals

What is the major product of non-structural carbohydrate digestion in the small intestine of non-ruminant animals?

Monosacharides

What is not a function of the pentose phosphate pathway?

 

Production of FADH2 for ATP generation through oxidative phosphorylation

Why is cellulose not able to be digested by animals?

 

Animals do not express an enzyme that targets the β-1,4 glycosidic bond between glucose and glucose

What location in the small intestine expresses the enzymes needed for the last steps of carbohydrate digestion?

 

Brush border membrane

What is the major product of structural carbohydrate digestion and fermentation in the hindgut of horses?

volatile fatty acid

What is the rank/order of carbohydrates according to rate of digestion and fermentation in the rumen in ruminant animals (1=fastest, 5=slowest)

1. Pectin (fastest)

2. Amylopectin

3. Amylose

4. Hemicellulose

5. Cellulose

Where does most of the acetyl-CoA that enters the citric acid cycle in the ruminant liver come from?

 

Acetate from rumen fermentation

What volatile fatty acid is an important energy source for rumen papillae?

 

Butyric acid

What animal enzyme hydrolyzes the β-1,4 glycosidic bond between D-galactose and D-fructose?

 

No animal enzyme does this

What best describes glucose transport in the small intestine?

 

ATP-dependent and Na-dependent

What is the monosaccharide unit and glycosidic bond configuration of Amylose?

D-glucose a-1,4 D-glucose

What is the monosaccharide unit and glycosidic bond configuration of maltose?

D-glucose a-1,4 D-glucose

What is the monosaccharide unit and glycosidic bond configuration of isomaltose?

D-glucose a-1,6 D-glucose

What is the monosaccharide unit and glycosidic bond configuration of sucrose?

D-glucose a-1, B-2 D-Fructose

What is the monosaccharide unit and glycosidic bond configuration of cellulose?

D-glucose β-1,4 D-glucose

What is the monosaccharide unit and glycosidic bond configuration of lactose?

D-galactose β-1,4 D-glucose