Carbohydrates ( Lecture ) Flashcards
are the major components of plant tissue
Carbohydrates
Carbohydrates making up to what percentage of the dry matter (DM)?
60% to 90%
Carbohydrates contain?
carbon, hydrogen, and oxygen
Carbohydrates contain carbon, hydrogen, and oxygen in the proportion found in?
water (CH20) and are hence hydrates of carbon.
are the basic energy source in animal cells.
Carbohydrates
Dietary carbohydrates obtained from?
plant-based products
traps solar energy and produces carbohydrates using carbon dioxide and water and gives off oxygen
chlorophyll in plant cells
In the plant cell, carbohydrates could be present in the cell content as?
sugar or starch
In the plant cell, carbohydrates could be present in the cell content as sugar or starch, or they could be associated with the?
cell wall structure
When animals eat plants like grains or grass, their bodies break down the carbohydrates (sugars and starches) in the food to get energy. This happens through?
metabolic processes
produces energy in a reverse process to that of photosynthesis.
animal metabolism
One method of classifying carbohydrates is based on the number of?
carbon atoms per each molecule of a carbohydrate and on the number of molecules of sugar in the compound.
Based on the number of carbon atoms, a carbohydrate can be classified as?
- triose (3 C)
- tetrose (4 C)
- pentose (5 C)
- hexose (6 C).
The suffix “ose” at the end of a biochemical name flags the molecule as a?
sugar
the end of a biochemical name flags the molecule as a “sugar.”
ose
are the most common sugars in animal tissues.
Pentoses and hexoses
Based on the number of molecules of sugar in the compound, carbohydrates can be classified as?
- monosaccharide
- disaccharide
- oligosaccharide
- polysaccharides
one unit of sugar
monosaccharide
two monosaccharides
disaccharide
three to fifteen monosaccharides
oligosaccharide
large polymers of simple sugars
polysaccharides
are often referred to as simple sugars (e.g., glucose) and cannot be hydrolyzed into simpler compounds.
Monosaccharides
Monosaccharides can be subdivided based on the number of?
carbon (C) atoms
Most monosaccharides in animal tissues are of?
5 C and 6 C sugars
Simple sugars are also subdivided into?
aldose or ketose
a sugar that contains an aldehyde structure
aldose
a sugar that contains a ketone group.
ketose
glucose is an aldose also called?
aldohexose
fructose is a ketose also called?
ketohexose
The chemical structure of glucose can be represented as a?
straight chain form and in cyclic form
In a biological system, glucose exists primarily as a?
cyclic form and very rarely in a straight form
is the form of carbohydrates found in circulating blood (blood sugar) and is the primary carbohydrate used by the body for energy production.
Glucose
is found in ripened fruits and honey
Fructose or fruit sugar
Fructose, or “fruit sugar,” is found in ripened fruits and honey and is also formed by digestion of?
disaccharide sucrose
is found along with disaccharide lactose in mammalian milk and is released during digestion.
Galactose
Glucose can exist as a? and has immense animal nutritional
implications.
( alpha ) and B ( beta ) isomers
Nutritionally important sugars are of the?
D-form
refer to stereo-orientation at asymmetric carbon position 5 in a hexose or carbon position 4 in a pentose.
D and L
Disaccharides are made up of two monosaccharides bonded together by a?
glycosidic (covalent) bond
glucose + fructose
Sucrose ( table sugar )
glucose + galactose
Lactose ( milk sugar )
a-D-Glucose + B-D-Glucose
Maltose ( malt sugar )
B-D-Glucose + B-D-Glucose
Cellobiose ( cellulose )
is the only carbohydrate of animal origin.
lactose (milk sugar)
a component of cellulose is important in animal nutrition.
cellobiose
Monogastric animals cannot digest?
cellulose
Monogastric animals cannot digest cellulose because they do not produce?
cellulase enzyme that can split B-D-Glucose.
oligosaccharides are commonly found in?
beans and legumes
Some oligosaccharides are used as substances to enhance the growth of?
good microbes (prebiotics).
Recently, there has been an increased interest in the use of different oligosaccharides as feed additives to enhance?
hindgut health
(glucose + fructose + galactose; 3 sugars)
Raffinose
(glucose + fructose + 2 galactose; 4 sugars)
Stachyose
are the most important carbohydrate in animal feed.
Polysaccharides
The functions of polysaccharides include?
energy storage in plant cells and animal cells or structural support
Components of cell wall structure are also called?
nonstarch polysaccharides, or resistant starch
Components of cell wall structure are also called nonstarch polysaccharides, or resistant starch, in animal nutrition, as they cannot be digested by animal enzymes but are fermented by?
hindgut and rumen microbes.
Polysaccharides can be?
homopolysaccharides or heteropolysaccharides.
Contains only one type of saccharide unit.
Homopolysaccharide
homopolysaccharides that are important in animal nutrition include?
starch (nonstructural form), glycogen (animal form), and cellulose (plant structural form)
Principal sugar form of carbohydrate in cereal grains (seed energy storage).
Starch
The basic unit is a-D-Glucose.
Starch
a-1,4 linkage-straight chain, nonbranching, helical structure
Amylose
a-1,4 linkage with alpha 1,6 linkage at branch points
Amylopectin
is the simplest of the
polysaccharides,
Amylose
is the simplest of the
polysaccharides, being comprised solely of glucose units joined in an alpha 1,4 linkage
Amylose
is water soluble and constitutes 15% to 30% of total starch in most plants.
Amylose
Amylose is water soluble and constitutes?
15% to 30% of total starch in most plants.
differs in how the glucose units are joined together.
Amylopectin
Alpha 1,4 linkages predominate, but a “branch” arises from an alpha 1,6 linkage. Such branches make the structure of amylopectin more complex than that of?
amylose
is not water soluble and constitutes 70% to 85% of total starch in plant cells.
Amylopectin
Amylopectin is not water soluble and constitutes?
70% to 85% of total starch in plant cells.
is the chief carbohydrate source in the diet of monogastric animals.
Starch
is the major form of starch in plant cells.
Amylopectin
is a form of starch found in animal tissue
Glycogen
Glycogen is a form of starch found in animal tissue and is hence called?
animal starch
is a polysaccharide that is physically related to amylopectin with basic alpha-D-Glucose but has a mix of a 1,4 and a 1,6 bonds.
Glycogen
exists in a small amount (< 1%) in liver and muscle tissue.
Glycogen
is the most abundant carbohydrate in nature. It provides structural integrity to plant cell walls.
Cellulose
Cellulose basic unit is
B 1,4 linkage, straight chain, nonbranching
No animal enzyme can break it; only microbial cellulase can degrade it.
Cellulose
Ruminant animals such as cattle, however, have bacteria in their rumen that contain the enzyme? . It breaks the beta 1,4 links of the glucoses in cellulose to release the sugar for energy.
cellulase
A component of plant cell walls with a mix of 5 C and 6 C sugars
Heteropolysaccharide
Carbohydrates are “hydrates of carbon” and have the generic structure of?
C(n)H(2n)O(n)
Glucose, mannose, and galactose are?
aldoses
fructose is a
ketose
The nature of glycosidic bonds influences the structural and chemical properties of the?
sugars and influences their ease of digestion
may be digested by mammalian enzymes.
Sugars that bond via an alpha 1,4 linkage
are resistant to digestion.
Sugars that are linked via the beta 1,4 linkage
Nutritionally significant disaccharides are?
sucrose and lactose
Starch consists of two types of molecules:
amylose (alpha 1,4 linked glucose) and amylopectin (alpha 1,4 and alpha 1,6 linked glucose).
Glycogen, a storage form of carbohydrates in the?
liver and muscles
Plant polysaccharides also include?
cellulose and hemicellulose and pectin (nonstarch polysaccharides)
The primary site of carbohydrate digestion is in the?
lumen of the small intestine
The primary site of carbohydrate digestion is in the lumen of the small intestine, where pancreatic amylase begins the digestion of?
starch granules
What species where there is some salivary amylase action in the mouth
In some birds
In some birds, there is some salivary amylase action in the mouth, but not in?
farm animals.
two forms of amylase
one amylase chops the chains randomly, while the other works more like a precision tool, cutting off specific pairs of sugars from the ends.
does not act on alpha 1,6 bonds that form the branch points in the structure of amylopectin.
Pancreatic amylase
The end products of amylase digestion include a mixture of?
glucose, maltose, and dextrins
are small pieces of starch that get broken down during digestion. An enzyme called alpha-1,6-glucosidase helps in this process by breaking specific bonds
Dextrins
helps in this process by breaking specific bonds in the dextrins
alpha-1,6-glucosidase
Dietary simple sugars, such as ?, do not need to be digested, as they can be absorbed through the intestinal epithelium directly.
glucose and fructose
Dietary simple sugars, such as glucose and fructose, do not need to be digested, as they can be absorbed through the ?
intestinal epithelium directly
The end products of starch digestion diffuse into the ?, where the final digestive processes occur.
brush border
Disaccharides such as? on the intestinal brush border then complete the degradation and are hydrolyzed to their constituent monosaccharides by enzymes on the brush border, and the monosaccharides released are absorbed into the enterocyte.
maltase and isomaltase
Disaccharides such as maltase and isomaltase on the? then complete the degradation and are hydrolyzed to their constituent monosaccharides by enzymes on the brush border, and the monosaccharides released are absorbed into the enterocyte.
intestinal brush border
Disaccharides such as maltase and isomaltase on the intestinal brush border then complete the degradation and are hydrolyzed to their constituent monosaccharides by enzymes on the brush border, and the monosaccharides released are absorbed into the.
enterocyte
is acted upon by sucrase to yield glucose and fructose for absorption.
Sucrose
In young animals kept on milk (preweaning), lactose is acted upon by lactase to yield?
glucose and galactose.
This enzyme activity is very low in young animals consuming milk and is stimulated by solid food consumption.
Amylase
Monosaccharides are absorbed both by?
simple diffusion and adenosine triphosphate (ATP)-dependent active transport.
How are monosaccharides absorbed into cells?
- Simple Diffusion: Monosaccharides move from high to low concentration without using energy.
- Active Transport: Requires energy (ATP); a sodium-dependent glucose transport protein moves glucose and sodium into the cell.
Carbohydrate-Digesting Enzymes:
• Amylase
• Disaccharidase
• Maltase
• Sucrase
• Lactase
do not secrete enzymes that digest the complex carbohydrates that are components of plant fiber (e.g., wheat, barley) and are acted upon by hindgut microbes to yield volatile fatty acids (VFAs).
Monogastric animals
What can high levels of NSP and glucans cause in the digesta of monogastric animals?
Viscous digesta and interference with digestion processes.
What are three potential issues in poultry fed high-NSP diets?
Wet litter, dirty eggs, diarrhea.
What is the main chamber of the ruminant stomach where carbohydrate digestion occurs?
rumen
What are the types of microbes involved in carbohydrate fermentation in the rumen?
Bacteria, fungi, and protozoa
are the products of carbohydrate fermentation in the rumen?
Short-chain fatty acids (VFAs)
Name the energy form produced by microbial fermentation in the rumen that is used by bacteria for protein synthesis and growth.
Adenosine triphosphate (ATP).
Major Volatile Fatty Acids Produced in the Rumen:
• Acetic acid
• Propionic acid
• Butyric acid
The end products of digestion in ruminants are?
volatile fatty acids and some monosaccharides.
What are the two stomach parts in young ruminants that are not fully developed?
Rumen and reticulum
What is the name of the reflex that allows milk to bypass the rumen and reticulum?
Reticular/oesophageal groove reflex.
List the stomach chambers that milk directly passes through due to the reticular/oesophageal groove reflex.
Omasum and abomasum.
What stimulates the reticular/oesophageal groove reflex?
Sucking
What happens to the reticular/oesophageal groove reflex when the ruminant is weaned?
It normally disappears.
What part of the stomach does solid food enter in a newborn ruminant?
Small rumen
From where does the young ruminant begin to pick up bacteria?
Mother and environment
What process occurs to the solid food in the small rumen?
Fermentation
What are the substances produced during the fermentation of solid food?
Volatile fatty acids (VFAs)
What do VFAs stimulate in the rumen?
Growth and development of the rumen, especially the papillae
What structure in the rumen grows and helps in nutrient absorption?
Papillae
What are the end products of rumen fermentation?
Microbial cell masses, volatile fatty acids (VFAs), and gases such as carbon dioxide, methane, hydrogen, and hydrogen sulfide.
List the gases produced during rumen fermentation.
Carbon dioxide, methane, hydrogen, and hydrogen sulfide.
All the digested and absorbed monosaccharides and volatile fatty acids enter into the?
liver
What factors influence the microbial population in the rumen?
The diet of the animal and the composition of the rumen microflora.
What are the main types of VFA produced by cellulolytic bacteria?
Acetate
What are the main types of VFA produced by amylolytic bacteria?
Propionate
What is the typical VFA ratio with a roughage diet?
65% acetate, 25% propionate, 10% butyrate
What is the typical VFA ratio with a concentrate-rich diet?
50% acetate, 40% propionate, 10% butyrate
What condition can occur from feeding animals a high-grain diet or changing their diet suddenly?
Rumen acidosis
What condition can occur from feeding animals a high-grain diet or changing their diet suddenly?
Rumen acidosis
