Chapter 6 Flashcards
(59 cards)
1
Q
Q: What elements make up amino acids and how many kinds are there?
A
A: Carbon, hydrogen, oxygen, and nitrogen.
central C, H, and amino group (NH2) plus acid (COOH)
20 different ones
2
Q
Q: What bond joins amino acids?
A
A: Peptide bond (via condensation).
3
Q
Q: What enzyme begins protein digestion in the stomach?
A
converts pepsinogen to pepsin (activated by HCl).
hydrochloric acid uncoils/ denatures proteins
breaks polypeptides to smaller ones and AAs
4
Q
Q: What are essential amino acids?
A
A: Amino acids the body can’t make and must get from food.
9 tpes
5
Q
Q: What is the final product of protein digestion?
A
A: Amino acids.
6
Q
Q: What is deamination?
A
A: Removal of the amino group, producing ammonia and a keto acid.
7
Q
Q: How is ammonia detoxified?
A
A: Converted to urea in the liver and excreted by the kidneys.
8
Q
Q: What is nitrogen balance?
A
A: Balance between N intake and N excretion as N is stripped from AAs during degradation
+ = intake above output (good)
- = output over intake (bad)
9
Q
Q: What are the protein deficiency diseases?
A
A: Marasmus and Kwashiorkor.
10
Q
Q: What is the RDA for protein?
A
A: 0.8 g per kg of body weight per day.
11
Q
Q: What is transamination?
A
Transferring an amino group from one amino acid to its corresponding keto acid (in liver)
12
Q
Q: What is PDCAAS?
A
A: A measure of protein quality based on digestibility and AA composition.
13
Q
Q: Name a complete protein source.
A
A: Eggs, milk, meat, or soy.
14
Q
Q: What is protein turnover?
A
A: Constant breakdown and synthesis of proteins by recycling AAs
15
Q
Q: What does protein do during starvation?
A
A: Broken down for energy and glucose.
16
Q
- Where does protein digestion begin?
A. Mouth
B. Stomach
C. Small intestine
D. Large intestine
A
B
mouth only does mechanical digestion
17
Q
- What is the RDA for protein for a 70 kg adult?
A. 35g
B. 56g
C. 70g
D. 80g
A
B (0.8 x 70)
18
Q
- What is an example of a conditionally essential amino acid?
A. Glucose
B. Tyrosine
C. Insulin
D. Pepsin
A
B
19
Q
- What is the process of using amino acids to make glucose called?
A. Glycogenesis
B. Gluconeogenesis
C. Lipolysis
D. Transamination
A
B
20
Q
- Which organ converts ammonia to urea?
A. Kidney
B. Intestine
C. Liver
D. Pancreas
A
C
21
Q
- Which of the following is a high-quality protein?
A. Corn
B. Beans
C. Eggs
D. Rice
A
C
22
Q
- What is the protein score that reflects quality?
A. BMI
B. PDCAAS
C. AMDR
D. BMR
A
B
23
Q
- What is the unique element in proteins?
A. Carbon
B. Hydrogen
C. Nitrogen
D. Oxygen
A
C
24
Q
- What hormone regulates blood sugar and is made from protein?
A. Glucagon
B. Insulin
C. ADH
D. Pepsin
A
B
25
29. What enzyme begins protein digestion?
A. Trypsin
B. Pepsin
C. Lipase
D. Amylase
B
26
33. What is protein turnover?
A. Digestion of protein
B. Storage of protein
C. Recycling of amino acids
D. Excretion of urea
C
27
what distinguishes amino acids from each other?
side group on carbon atom (needs 4 bonds, 4th attachment)
differs in size, shape and electrical charge
28
secondary structure of AAs
polypeptide shape
determined by weak electric attraction in chain
between H(+) and O (-) cause the structure to twist into helix = strength
29
tertiary structure of AA
polypeptide tangles
when chains twist, can become hydrophilic or hydrophobic
30
quaternary structure of AAs
2 or more polypeptide interactions
1 molec hemoglobin made of 4 polypeptide chains holding irons
31
protein denaturation
- When proteins are subjected to heat, acid or other conditions that disturb their stability
- Uncoil, lose their shapes and ability to function
o Ex. Frying an egg, unable to turn white part back to clear after heating
32
small intestine role in protein digestion/ absorption
Pancreatic and intestinal proteases break polypeptides into tripeptides and dipeptides.
Peptidase enzymes on intestinal cell walls split most of these into single amino acids.
Key enzymes: tripeptidase, dipeptidase, endopeptidase, exopeptidase.
Only a few small peptides escape full digestion and enter the bloodstream intact.
33
intestinal cells and AAs
Aa used for energy or synthesize compounds
unused is transported into capillaries to liver
34
proteome
all the proteins synthesized by our cells
- More than 1 million kinds of proteins in the body (only a few thousand have been studied well)
- Each protein has a standard AA sequence specified by heredity
- Each protein has a specific function, determined during protein synthesis
- Protein synthesis is dependent on a diet
35
transcription and translation
transcription: DNA template to make mRNA
translation: mRNA attaches to 1 ribosome, RNA specifies sequence that AAs line up for synthesis of protein
36
ribosome and tRNA
ribosome: protein making machine of cell
tRNA (transfer): cluster in ribosomes, wait, tRNA carries AA or brings them to mRNA after
37
sickle cell anemia
abnormal hemoglobin
2/4 peptide chains not good
(valine instead of glutamic acid)
cannot carry oxygen due to shape
complications: more energy needs, blood clots, dehydration, fatality
38
roles of proteins
build body (collagen, calcium for bones, skin cells every 30 days)
enzymes to break, build, transform (judge that marries/ divorces ppl)
hormones (endocrine glands)
fluid balance
acid-base regulation
transporters of nutrients
antibodies (antigens)
energy & glucose source
blood clotting
vision
39
responses of hormones below;
insulin + glucagon
antidiuretic hormone
thyroxine from tyrosine
Insulin & Glucagon -> Blood glucose control
Antidiuretic hormone -> Regulates fluid and electrolyte balance
Thyroxine from tyrosine -> Regulates BMR
40
protein related edema caused by...
Excessive protein losses from inflammation and critical illness
Inadequate protein synthesis caused by liver disease
Inadequate protein intake
41
what controls acid-base balance?
hydrogen ions
Proteins have negative charges that attract hydrogen, which they then accept and release
Acidosis
Alkalosis
- Both lead to coma and death since they denature working proteins (disturb shape = useless protein)
42
how are amino acids used to make fat?
o When protein is abundant, body will shift to use more protein than fat for energy
o Excess amino acids converted to fat and stored for later use
43
how does the body make a certain dispensable AA that is missing?
using a keto acid and a nitrogen source! (Ammonia can provide a nitrogen for this process)
44
failure to excrete urea leads to what diseases?
o Kidney disease: urea in blood
o Liver disease: ammonia in blood
45
AAs to other compounds (tyrosine & tryptophan)
-AA Tyrosine → epinephrine (neurotransmitters), melanin, hormone thyroxin (regular BMR)
-AA Tryptophan → precursor for niacin (vitamin), serotonin
46
plant source grams per serving of protein foods
Beans, legumes, minimal amount found in vegetables (2g/serving) and grains (3g/serving)
47
reference protein
quality of protein determined by comparing its AA composition with essential amino acid requirements of preschool age kids
48
heart disease & protein intake
o High intake of animal protein (containing SFA) can increase risk of HD
o Replacing animal proteins with plant-proteins can reduce risk
49
osteoporosis and protein intake
kidneys and protein intake
o Increase protein intake, increases calcium excretion
o Consider excess protein vs inadequate Ca
Kidneys;
o Increased protein=increases work of the kidneys to excrete the end products of protein metabolism
50
PEM types and what they are
Kwashiorkor (PRO deficiency)
- Edema of belly & lower extremities
- Skin rashes , hair loses pigmentation
- May result from severe acute malnutrition of too little protein
Marasmus
- Energy deficiency, Affects Skin & bones, Shriveled
-Chronic inadequate food intake (inadequate energy, vitamins, minerals, & PRO)
51
how to calculate your own protein intake
o Calculating your recommended protein intake : 2.2lbs in 1kg
o If you are 180lbs, divide this by 2.2lbs/kg = 81.8kg
0.8g/kg/d x 81.8kg = 65g protein/day
* SINCE RDA FOR PROTEIN IS 0.8
52
protein amount in dairy and fruits/ veg/ grain
- Dairy products
o 1C/250 mL of milk provides ~8g protein
- Fruits, Vegetables & Grains
o Vegetables and grains provide small amount of protein per serving (~2-3g)
53
post workout snack
(within 15 minutes)
3:1 ratio of quick carbs to protein
Gold standard: 1-2 cups chocolate milk
54
What are nutrigenomics and nutrigenetics?
Nutrigenomics: How nutrients influence gene activity
Nutrigenetics: How genes affect nutrient use and metabolism
55
What is the goal of nutritional genomics?
To give personalized dietary recommendations based on an individual's genes.
56
What is epigenetics and how does it work?
Epigenetics studies how environmental factors (e.g., nutrients) turn genes on/off without changing DNA.
Example: Folate & B12 silenced obesity-related genes in mice.
57
What is methylation and how does it affect gene expression?
Methylation adds CH₃ groups that block protein binding, turning genes off.
Folate increases methylation (protective)
Vitamin C & Omega-3s decrease methylation
Green tea inhibits methylation to activate protective gene
58
Why don’t people respond the same to diet?
Genetic differences affect nutrient response.
59
What is the human proteome project aiming to do?
To identify all proteins made by genes and how they relate to aging, disease, and diet-responsive gene expression.
