Learn: Exam 3

What nutrient that we've discussed provides the most energy to an animal? What does it have more of?

Lipids/fats; has more hydrogens

Does energy increase or decrease with more hydrogens on a molecule?

Energy increases

Does melting point increase or decrease as number of double bonds increases?

Melting point decreases

Does melting point increase or decrease with length of a fatty acid chain?

Melting point increases

Do most naturally occurring fatty acids have an odd or even number of carbons?

Even number

How many carbons are in short chain fatty acids?

2-6

How many carbons are in medium chain fatty acids?

8-12

How many carbons are in long chain fatty acids?

14-24

What is the difference between saturated and unsaturated fatty acids?

Unsaturated have at least 1 double bond

What type of peptidase cleaves the peptide bonds nearest to an amino or carboxyl group?

Exopeptidases

What type of peptidase cleaves the peptide bonds inside the peptide chain (not next to an amino or carboxyl group)?

Endopeptidases

What are the term for an inactive enzyme?

Zymogen

Why does the pancreas produce zymogens rather than active digestive enzymes?

If they were active, they would start digesting the pancreas tissue

What cell in the stomach produces pepsinogen?

Chief cells

What activates pepsinogen and what cell produces the activator?

HCl activates; produced by the parietal cells

What is the term that describes a process that causes a protein to uncoil (lose its shape) thus losing its ability to function?

Denaturation

What does the pancreas produce to buffer chyme coming from the stomach?

Bicarbonate

What originally activates trypsinogen to trypsin?

Enteropeptidase (aka enterokinase)

What pancreatic protease can activate itself and two other zymogens?

Trypsin

What 3 things does the small intestine brush border produces to help protein digestion?

Enterokinase, aminopeptidases, and dipeptidases

Do most proteins enter the bloodstream as amino acids or small peptides?

Amino acids

What happens if small peptides are absorbed into the bloodstream?

It triggers an immune response (allergic reaction)

What enzyme inside the enterocyte (epithelial cell) breaks down small peptides into amino acids?

Peptidase

What type of macronutrient is gluten?

Protein

What type of dietary protein is digestible by rumen microbes?

Rumen Degradable Protein (RDP)

What type of dietary protein escapes rumen digestion and enters the small intestine unaltered?

Rumen Undegradable Protein (RUP)

What type of protein is not made up of amino acids?

Non-protein nitrogen (NPN)

What enzyme produced by the microbes cleaves degradable protein into amino acids and peptides?

Protease

What microbial enzyme breaks amino acids into ammonia, ATP, VFAs, and CO2?

Deaminase

What determines the biological value of a protein?

The essential amino acid composition

What term describes when a cow eats a low quality straw and makes it into high quality microbial protein?

Up regulation

What two things do microbes need to make microbial protein and to replicate?

ATP and Nitrogen

What is meant by the term "synchronization" concerning choosing feedstuffs?

Need to match protein and energy amount so that they microbe gets enough N and ATP

What process makes toxic ammonia into less toxic urea in the liver?

The urea cycle

What enzyme makes urea into ammonia in the rumen?

Urease

Why can we feed urea (in moderated amounts) to ruminants but not to monogastrics?

Ruminants are able to use the urea to make amino acids but monogastrics cannot do anything with it (except pee it out)

What end do you start counting from when doing omega nomenclature?

Methyl

What end do you start counting from when doing delta nomenclature?

Carboxyl

What is the difference between cis and trans double bonds?

Cis has hydrogens on the same side; trans has them on opposite sides

What is the difference between conjugated and non-conjugated fatty acid double bonds?

Non-conjugated have a CH2 group between the double bonds, conjugated does not

Which essential fatty acid has 2 double bonds, is an omega-6, and a delta 9, 12?

Linoleic acid

Which essential fatty acid has 3 double bonds, is an omega-3, and a delta 9, 12, 15?

Linolenic acid

What process is done to make a fatty acid more solid at room temperature by adding hydrogens?

Hydrogenation

What are triglycerides composed of?

glycerol backbone and 3 fatty acids

What are glycolipids composed of?

A glycerol backbone, 2 fatty acids and one/two sugars

What are phospholipids composed of?

glycerol backbone, 2 fatty acids, and a phosphate group

What does the process of emulsification? Where is it produced and where is it stored?

Bile; produced by the liver; stored by the gallbladder

What anchors lipase to a lipid droplet?

Colipase

What does pancreatic lipase do?

It removes 2 fatty acids from a triglyceride and leaves a monoglyceride as a result

Why do lipids not need a transport protein to get across the enterocyte membrane?

The cell membrane is made of phospholipids

What is formed inside the enterocyte to prevent fat from being directly released into the bloodstream unprotected?

Chylomicrons (which are put into the lymphatic system first)

Why can we not produce specific types of fatty acids with ruminants?

The rumen microbes alter the fatty acids that we feed them. We have no control over what the microbes do to those fatty acids

What does hydrolysis do to a triglyceride?

It breaks it into 3 free fatty acids (glycerol backbone is removed)

What do rumen microbes accomplish with biohydrogenation?

They reduce double bonds (make unsaturated bonds into saturated bonds)

What does isomerization by the microbe do to fatty acids?

It makes a cis double bond into a trans double bond

What microbial enzyme is responsible for isomerization?

Isomerase