Protein Metabolism Flashcards
1
Q
Obj: Describe functions and structures of proteins
A
2
Q
Obj: Contrast Essential vs Non-essential Amino acids
A
3
Q
Obj: Describe protein digestion and metabolism
A
4
Q
Obj: Compare the protein requirements of carnivores, omnivores, and herbivores
A
5
Q
Obj: List and discuss methods to measure protein in the body and food
A
6
Q
Obj: Determine Protein quality
A
7
Q
Obj: describe protein assessment
A
8
Q
Obj: Describe protein deficiency symptoms
A
9
Q
What are the sources of protein in animal diets?
A
- Plant
- Animal
- Microbial
10
Q
What is a Protein?
A
- A sequence of amino acids connected by peptide bonds
- Consists of :
- Carbon
- Hydrogen
- Nitrogen
- Oxygen
- Sulfur*
- Phosphorous*
11
Q
What is the basic structure of amino acids?
A
- Central carbon bonded to hydrogen
- Amino group (NH2)
- Carboxylic group
- R-Group - makes the different AA
12
Q
What is the difference between an Essential vs Non-essential Amino Acid?
A
- Essential:
- Indispensable
- The body is unable to make or can only make in inadequate quantities
- Need to be consumed form the diet
- 10 essential Amino Acids for most nonruminant animals
- Depends on species and physiologic state
- Non-Essential:
- Dispensable
- The body can make in large enough quantities
- made from essential AA
- Not necessary to consume in the diet
- 10-12 nonessential AA
13
Q
What are Conditionally essential Amino acids?
A
- Conditionally indispensable
- Can become essential in certain physiologic conditions
- Examples:
- Glutamine - fuel for enterocytes, macrophages, lymphocytes
- becomes essential for intestinal mucosal during illness
- Glutamine - fuel for enterocytes, macrophages, lymphocytes
14
Q
What are the Essential Amino Acids:
A
- Phenylalanine
- Valine
- Threonine
- Argenine
- Tryptophan
- Isoleucine
- Methionine
- Histidine
- Leucine
- Lysine
15
Q
What additional Essential AA do hens need?
A
Proline
16
Q
How are proteins classified?
A
- Based on number of AA:
- Dipeptides
- Tripeptides
- Oligopeptides
- Polypeptides
17
Q
What is the basic structure of proteins?
A
- Amino acids in a single polypeptide chain
- the Sequence of AA for each protein is unique and genetically determined
18
Q
What are the limiting amino acids in:
- Beans
- Grains (rice)
- Nuts and seeds
- Vegetables
- Corn)
A
19
Q
What is the secondary, tertiary and quaternary structure of proteins?
A
- Secondary - α-Helix or β-Folded Sheets
- Tertiary - α-Helix and β-Folded Sheets
- Quaternary - multiple tertiary structures together
20
Q
What determines the nutritional value of proteins?
A
- its primary structure
- (i.e. amino acid composition)
21
Q
What determines a proteins digestibility?
A
- its tertiary structure
- Globular proteins are more easily digested than filamentous proteins such as collagen, elastin and keratin
22
Q
What parts of the body contain collagen and elastin?
A
- skin
- tendons
23
Q
What part of the body contains keratin?
A
- Hair
- Nails
- Feathers, claws, beaks
- hooves, horns
24
Q
What functions do proteins serve?
A
- Enzymes
- Some hormones
- antibodies
- fluids balance
- regulate pH
- Transport proteins
25
What are Enzymes? Function? Examples?
* proteins that catalyze chemical reactions without being used up or destroyed in the process
* Anabolic and catabolic functions
* Ex:
* Salivary amylase
* Trypsin
26
What are hormones? Examples?
* Chemical messengers made in one part of the body but act on cells in other parts of the body
* Ex:
* Insulin
* CCK
* PTH, calcitonin
* Growth Hormone
27
What are antibodies?
* proteins that attack and viruses that cause infection
28
How do proteins help maintain the bodies fluid balance?
* Fluid is forced into tissue spaces by blood pressure generated by pumping action of the heart
* Fluid returns to blood because of ‘osmotic pressure’ created by albumin
29
How do proteins help in the regulation of pH?
* AA in proteins accept Hydrogens when the pH is too low
* AA in proteins donate Hydrogens when the pH is too High
30
What transport proteins are there in the body?
* Blood:
* Lipoproteins
* Hemoglobin
* Cell membrane transport
31
How are Amino Acids used for energy?
32
how are Proteins digested in monogastrics vs ruminants?
33
What is the waste product of protein catabolism? how is it created? excreted?
34
What are the differences between somatic proteins and visceral proteins?
* Somatic Protein
* muscle mass
* depleted in **chronic** starvation
* Visceral Protein
* serum proteins
* depleted in **acute** starvation
35
What is the protein requirements of Cats?
* High protein requirement
* 30-50% protein DMB
* Need highly digestible animal proteins
* short digestive tract
36
Why will cats die on an arginine deficient diet?
* Arg drives urea synthesis cycle
* ⇣Arg = hyperammonemia
37
What is the protein requirements of Dogs?
* Mid-range
* 15-30% DMB
* Animal and plant protein sources
* Effectively digest starches
38
What is the protein requirements for herbivores?
* Relatively low
* ~8 - 16% DMB
* Enlarged fore stomach or hindgut
* Utilize extensive fiber in the diet
* bacterial degradation of feedstuffs
39
How is Crude protein calculated?
* Feed is analyzed for Nitrogen content
* N content multiplied by a correction factor of 6.25
* Nitrogen makes up about 16% of protein
* 100/16 = 6.25
40
What determines a proteins quality? Why is protein quality important?
* Biological Value
* High value - Essential AA \> Non-essential
* low value - essential AA \< Non-essential
* Digestibility
* High quality protein ⇢ less needed to meet AA requirements
41
What are Maillard Reactions? why do they matter?
* Proteins binding to reducing sugars
* reduces protein availability
42
What are the clinical signs & laboratory findings of protein malnutrition?
* Weight loss
* Decreased growth rate
* muscle wasting
* poor haircoat
* hypoalbuminemia
* low serum protein
* anemia
* decreased immune function
* Hepatic lipidosis
43
Why do animals with hepatic/renal disease need limited protein?
* Problems excreting the excess nitrogen
* uremia - ⇡ blood urea
* hepatoencephalopathy ⇢ ⇡ blood ammonia
