AN SC 260 - 4
What are the functions of carbs?
Major components of plant tissue
Main energy source for most livestock
Free CHO central to metabolism
What are some examples of monosaccarides?
Glucose - hexose/dextrose
What is important about glucose?
Ultimate source of E for most animal cells
Central to metabolism
No degradation needed for absorption
What are some examples of disaccharides?
What does sucrase do and what is released?
Glucose and fructose released
What is maltose a product of and where is it present?
Germinating Grain (beer production)
What are the bonds found in polysaccharides?
Alpha and Beta
What significance do alpha and beta bonds have?
Animals can break down alpha bonds but not beta bonds
Microbes in ruminants can break down beta bonds
What bonds are found in starch?
Amylose - alpha-1,4 linked glucoses
Amylopectin - alpha 1,4 linked glucoses with alpha-1,6 branches
Why is starch more soluble in hot water than in cold water?
Insoluble in cold water
When heated, water in starch will gelatinize which increases accessibility by enzymes
What happens amylose and amylopectin upon cooling after gelatinization?
Amylose - re-crystalizes
Amylopectin - gels
What are some properties of Cellulose?
Unbranched chain of beta-1,4 linked glucoses
Most abundant plant constiuent
What are some properties of hemicellulose?
More digestible than cellulose
Acid releases arabinose side chains
What is lignin?
Derived from wood
Not a carb
Repeating phenylpropane units
What are soluble fibres?
Soluble non-starch polysaccharides
beta-linked sugar molecules (indigestible by animals)
What is an example of a soluble fibre?
What is starch broken down by and where?
What are the steps of starch breakdown?
Starch => dextrins => maltose => glucose
Where does most of absorption occur?
Small intestine - duodenum & jejunum (mostly beginning of jejunum)
How glucose transported across the membrane?
Sodium symport - 2 Na+ per 1 glucose
Down  gradient
What are the precursors for gluconeogenesis?
Fat (glycerol, no net synth of glucose)
Why is it important to replenish glycogen stores?
Reserves only stored in liver for 1/2 day
Brain & red blood cells completely dependent on glucose for E
What are the steps of glycolysis and how many ATP are produced?
Glucose => fructose 1,6 bisphosphate => pyruvate
Net 8 ATP generated
Pyruvate => 2 Acetyl CoA
2 Acetate => 2 CO2 + 2 H2O
Net 24 ATP generated
TOTAL 38 ATP
What is the precursor for fat synth?
What is ketosis?
Not enough glucose in blood
Fat metabolized for energy
Ketones produced faster than can be metabolized
What is insulin-dependent diabetes mellitus (Type I) caused by?
Destruction of Islets of Langerhans in pancreas
What is non-insulin-dependent diabetes mellitus (Type II) caused by?
Deficiency of cell-surface binding sites for normal glucose uptake
Aggravated by obesity
What is the most important form of diabetes in domestic animals?
Gestational diabetes mellitus
AN SC 260 - 4
Chapter 4 - Carbohydrates in Animal Nutrition