Midterm

T/F. Classified as a group of dietary fiber, pectins cannot be digested by animal enzymes, but can be digested by microbial enzymes.

True

T/F. Anabolism is one type of metabolism, which refers to those reactions that break down dietary nutrients.

False

T/F. In general, most plant tissues contain much more carbohydrates that animal tissues do.

True

T/F. In birds, food passes through the gizzard before entering the proventriculus.

False

T/F. Hydrolysis of one maltose molecule will produce two glucose molecules.

True

T/F. Animal life requires energy. Carbohydrates can provide animals with energy and thus carbohydrates (or starch) are a class of dietary essential nutrients.

False

The small intestinal epithelia cells can readily absorb some nutrients in one of the following groups of substances. Which group is it?

Monosaccharides

Which one of the following monosaccharides or oligosaccharides that contain 5 carbon atoms in a single sugar unit?

Not Galactose, Maltose, Mannose, Fructose

Carbohydrates do not include \__________.

Lignin

Which of the following GI sections is the major site of roughage fermentation in the horse?

Colon

Which of the following nutrients can be synthesized by the ruminal bacteria?

Proteins, vitamins, minerals, water, energy, and carbohydrates

Starchyose is an oligosaccharide that contains \_______________ sugar units in its one molecule.

4

Even though birds do not have teeth, they can still "chew" or grind the feed or ingesta in one of the following parts of their gastrointestinal tract.

Ventriculus

A homo-polysaccharide with the main chain being alpha-glucoses linked by alpha 1-4 glycosidic bonds. After every 7 to 10 glucose residues on the main chain there branches out a side chain that is linked to the main chain by an alpha 1-6 glycosidic bond. What is this polysaccharide?

Glycogen

Which one of the following polysaccharides does not have 6 carbon sugar units in its molecule?

Xylan

Which one of the following transporters is responsible for the absorption of glucose by the intestinal epithelial cells?

SGLT1

Which one of the following metabolic pathways belongs to the anabolism category?

Amino Acid Deamination

The compartment in ruminant stomach that is most like a monogastric stomach is the \______________.

Abomasum

The salivon consists of at least three types of cells. These types of cells are \________________, \______________, and \____________.

Acinar cells, Myoepithelial cells, and Ductule cells

The two general types of reactions in photosynthesis are \______________ and \_____________.

Light Reaction and Calvin Cycle

The gastrointestinal digestion of nutrients can be regulated by neuro-humoral stimuli. Please list the 4 classic hormones that were covered in the class.

Gastrin, Secretin, Cholecystokinin (CCK), and Gastro inhibitory polypeptide (GIP)

Small intestinal wall can secrete various digestive enzymes. Please list at least four.

Maltase, Lactase, Sucrase, Lipase

T/F. Glycolysis takes place in the mitochondria and therefore some of the reactions during this pathway require oxygen (O2) as the final electron receiver.

False

T/F. The electron transport chain pathway takes place in the mitochondria and therefore it requires oxygen (O2) as the final electron receiver.

True

For a glycolysis pathway to complete, it will cost 2 ATP molecules during the early stage of the pathway, but it will produce 4 ATP molecules during the late stage of the pathway.

True

T/F. TCA cycle (Krebs cycle) takes place in the cytoplasm and therefore no oxygen (O2) is required for all those biochemical reactions.

False

T/F. Pyruvate dehydrogenase pathway takes place in the mitochondria.

True

T/F. Rumen, like mitochondria, does not have oxygen (O2) so a glucose molecule can be totally oxidized to 6 CO2 molecules with the help of microbial enzymes.

False

A complete Electron Transport Chain includes five enzyme complexes (labeled as I through V) along the inner mitochondrial membrane. The name of complex V is \________________.

ATP synthase

How many CO2 molecules are generated from one Krebs cycle?

2

How many CO2 molecules are generated from one complete glycolysis pathway?

0

The first enzyme that is needed for the first step of glycolysis pathway is \__________________.

Hexokinase

Rumen microbial enzymes can digest dietary fiber to generate the following short chain fatty acid(s) ?

Acetate, Butyrate, Propionate

After at least 4 catabolic pathways, one glucose molecule can be totally oxidized to 6 CO2 molecules and about 40% of its energy will be finally trapped in \_________ ATP molecules.

36

Following an abrupt increase in grain intake, soon after pasture grazing, a beef cattle can readily develop a condition called metabolic acidosis. Which acid is mainly responsible for this condition?

Lactic acid

Besides ATP, H20, and NADH, another important final product of the glycolysis pathway is \_______________.

Pyruvate

Besides ATP, CO2, and NADH, another important final product of the Krebs Cycle is \_______________.

FADH2

The first enzyme that is needed for the first step of TCA cycle (Krebs cycle) is \____________________?

Citrate synthase

The chemically reactive group of Co-enzyme A is \__________________?

-SH

This molecule called \__________________ enters the TCA cycle via fusing with OAA.

Acetyl-CoA

How many CO2 molecules are generated from a complete oxidation of one glucose molecule?

6

How many CO2 molecules are generated from one pyruvate dehydrogenase pathway?

2

One of the end chemical products of the glycolysis pathway is \__________________ that needs to enter into other two or three pathways to release more energy.

Pyruvate

How many ATP are produced when 1 NADH goes through electron transport chain?

3

Please describe gluconeogenesis (Please mention at least 3 different types of substrates). Why is gluconeogenesis is especially important in ruminants?

Gluconeogenesis is a process of synthesizing glucose from non-CHO sources. Three different substrates are propionate, lactate, or amino acids. Gluconeogenesis takes place in the liver and kidney. It is especially important in ruminants because there is very little glucose absorbed in the GIT of ruminants. Glucose in ruminants are degraded by microorganisms and only fatty acids can absorb.

T/F. Aspartate and glutamate are two basic amino acids.

False

T/F. In nature, animal and human do not have any metabolic mechanism to regulate the amino acid concentrations in their blood.

False

T/F. It is the sequence of amino acids (including their chemical properties) that determines the structure of the protein and in turn, the protein properties and protein functions.

True

T/F. Proteins are usually synthesized from non-protein nitrogen (NPN) in the abomasum of the adult ruminant.

False

T/F. An endopeptidase cleaves the peptide bonds in the middle of the amino acid chain (i.e. the middle of a protein) to form multiple peptide fragments.

True

T/F. Urea cycle is a very important metabolic pathway to degrade the carbon skeleton left from amino acid catabolism.

False

T/F. Small intestinal epithelial cells can not only absorb free amino acids, but also can absorb di- and tri- peptides.

True

T/F. When a cell synthesizes a protein, an amino acid chain, it needs all kinds of amino acids. We know that if the cell misses one amino acid, usually it will still be okay because the process can skip this amino acid but this process cannot skip two or more amino acids.

False

T/F. Amino acid degradation can also provide animal body with energy.

True

T/F. In animal body, only the L-amino acids (not the D-amino acids) can be used as building blocks for protein synthesis.

True

Which one of the following amino acids is an acidic or anionic amino acid?

Glutamate

Which one of the following amino acids is actually an imino acid?

Proline

For a protein to be synthesized in a body (i.e. in a cell) one or more of the following substances need to be available on site.

rRNA, tRNA, mRNA, and free amino acids

A protein polypeptide chain can fold into a coiled alpha-helix and/or a pleated beta-sheet that forms one or more of the following levels of protein structure?

Secondary level

Which one of the following amino acids is a ketogenic amino acid?

Lysine

The Urea Cycle for ammonia detoxification in the body involves the following amino acids:

L-Arginine, L-Ornithine, L-Citulline, and Aspartate

Alanine dehydrogenase can remove an ammonia (-NH3) group from an alanine molecule and after that the alanine molecule will become \_______________.

Pyruvate

Which of the following amino acids is NOT an essential amino acid?

Glycine

Which of the following amino acids is a sulfur containing amino acid?

Methionine

Proteins are made up of oxygen, carbon, hydrogen, and \________________.

Nitrogen

Which one of the following amino acids is an aromatic amino acid?

Tyrosine

Which one of the following amino acids is a non-proteinogenic amino acid that plays a role in the urea cycle?

Ornithine

Which one of the following amino acid transport system is responsible for the small intestinal absorption of cationic (basic) amino acids?

y+ system

Through laboratory analysis, we learned that the nitrogen content of a poultry diet is 3.0%. Please tell me the crude protein content (%) of this diet is roughly \_____________.

18\.8%

In the small intestine, free amino acids are actively absorbed via various amino acid carrier systems. Please list at least three systems.

y+ system, X-AG system, and X-C system

What chemical bond(s) that connect(s) amino acid residues together (in a ring structure) to form a big protein molecule?

Peptide bonds

Which three amino acids are basic amino acids?

Lysine, Histidine, and Arginine

Which metabolic pathway that the animal liver or kidney cells need to go through to get rid of the NH3 released from amino acid deamination?

Urea Cycle

From animal nutrition standpoint, please describe the concept of ideal protein and also the concept of "the first limiting amino acid". Why the first limiting amino acid is so important for the animal?

The limiting amino acid is so important because a protein will stop if a specific AA is not available. Deficiency of one AA will stop the whole process. The concept of ideal protein is in a feed/diet a departure of AA ratios from the pattern ratios in an ideal protein. The departure lowers. This causes the reduction because of the supply of one essential AA is insufficient/unavailable. That amino acid that is unavailable is the limiting amino acids and that is why its important to place specific feedstuff to adequately adapt to those limiting amino acids.

T/F. The main function of canine teeth of an animal is for the tearing and separation of feed materials.

True

T/F. Cholecystokinin (CCK), a peptide hormone, is secreted by the I-cells in small intestinal mucosal epithelium upon stimulation by dietary fat and protein. Its function is to stimulate gallbladder to contract and to relax Oddi sphincter.

True

T/F. Of a monogastric stomach, the 1st of the four regions is called cardiac region that does not secrete digestive enzymes.

False

T/F. Energy is also a class of nutrients just like the class of carbohydrates.

False

T/F. The materials leaving out of animal stomach is called chyme. Is this statement true or false?

True

T/F. Digestive enzymes are in general are heat liable, have substrate specificity, and need to work at an optimal temperature. But they can work at any pH condition.

False

Which of the following organs does not belong to animal digestive system?

Spleen

Which region (or subdivision) of the stomach contains peptic/chief cells that secrete pepsinogen for pepsin?

Fundic Region

Salivary glands include the following pairs of glands, all of which have ducts lead the saliva (secreted from the acinar cells) into the mouth.

Sublingual glands, Submandibular/submaxillary glands, and Parotid glands

For digestion and absorption of nutrients, the most active portion of the pig's digestive tract is in the \___________.

Small intestine

Insulin is a blood glucose concentration regulation hormone secreted from the \________________ (cells) located in the Islets of Langerhans of animal and human pancreases.

Beta cells

Along the epithelial villi of the intestine are some simple columnar or tubular cells that secrete mucin to form mucus to protect the epithelial mucous membrane. These cells are called \_____________.

Goblet cells

Who said/hypothesizes that they were a lot of foods (or feeds) but only one thing (i.e., the nutrient) was needed by humans or animals?

Hypocrites (460-370 BC)

Based on your knowledge gained from this course, these three enzymes: sucrase, maltase, and lactase, should be secreted by one of the following organs/glands.

Salivary glands

Which regions (or subdivision) of the stomach contains G cells that secrete gastrin (a hormone)?

Pyloric region

Which of the following nutrient groups does not contain energy for the animal?

Minerals

In order to be an animal nutritionist, you should have at least the following knowledge...

How to analyze nutrient compositions of feedstuffs in laboratory and how to formulate animal diets.

7 basic functions of the digestive system

Prehension, Mastication, Deglutition, Digestion, Absorption, Transmission, and Defecation

Functions of Teeth

seizes and brings feed to mouth, takes feed to molars, assists chewing, taste feed with taste buds, initiates deglutition, and can be used in grooming.

Functions of Pharynx, Uvula, and Epiglottis

common pathway for bolus and air, the help from uvula and epiglottis can help prevent bolus from entering the nasal cavity and larynx by reflexes, and the mechanics of swallowing.

Esophagus

a hollow muscular tub, opening just above pharynx, to pass the swallowed ingesta/bolus from the mouth to the stomach through peristaltic waves.

What is the capacity of the stomach?

2 gallons

Stomach

can secrete gastric juice, overall function to store, digest, and move ingesta.

What are the subdivisions of the stomach?

Esophageal regions, Cardiac (gland) region, Fundic (gland) region, and Pyloric (gland) region.

Esophageal region

extension of the esophagus, non-glandular (no secretion of fluids!!)

Cardiac region

cardiac glands secrete mucus to protect the stomach lining.