Nutrition and Metabolism Flashcards
1
Q
essential nutrients
A
body can’t make it
2
Q
Our bodies are efficient at converting one type of molecule into another, what organ is especially good at this?
A
liver
3
Q
4 calories per gram
A
protein and carbs
4
Q
9 calories per gram
A
fat
5
Q
glucose, fructose, galactose
A
monosaccharide
6
Q
sucrose, maltose, lactose
A
disaccharide
7
Q
polysaccharide definition and examples
A
insoluble
no sweet taste
(starchy potatoes, spaghetti)
8
Q
starch
A
Storage of glucose
9
Q
Plant cell wall (structural); “fiber”
A
cellulose
10
Q
animal polysaccharides made of glucose: glycogen
A
Storage of glucose (liver, muscle)
11
Q
insoluble and soluble fibers which kind of macro
A
polysaccharids
12
Q
soluble fiber
A
(e.g., pectin) lowers blood cholesterol levels
13
Q
insoluble fiber
A
(e.g., cellulose) provides roughage, increases bulk of stool, eases defecation
14
Q
major carb used to make ATP
A
glucose
15
Q
other sugars converted into
A
glucose
16
Q
high and low carb diets can be healthy, but if you restrict it too much, side effect is…
A
ketoacidosis
17
Q
more complex carbs better than
A
simple carbs
18
Q
don’t need to know about deficits or excesses of carbs
A
no
19
Q
carbs should be what percentage of daily intake
A
45-65 % (RDA)
20
Q
draw triglyceride
A
long carbon chain (3 C’s in column with things branching off to the right)
21
Q
phospholipid similar to triglycerides, but
A
only 2 fatty acids
“polar” head connects to “nonpolar” tail
22
Q
steroids structurally dissimilar from other lipids
A
four hydrocarbon rings
23
Q
most important steroid
A
cholesterol
24
Q
cholesterol
A
Our liver produces ~80%
The rest comes from our diet
Helps maintain cell membrane fluidity
25
cholesterol serves as raw material so body can synthesize
```
Vitamin D
Steroid hormones (e.g., sex hormones)
Bile salts (help with digestion)
```
26
sat fats found in
meat, dairy
27
unsat fats found in
plants, seeds, nuts, olive oil, vegetable oil
28
cholesterol sources
animal products
| liver makes 85%, regardless of diet
29
liver can make one fatty acid into another except linoleic and linolenic, which are
essential fatty acids
30
uses for fats in the body
1) adipose tissue (cushion, insulation, efficient for concentrated energy storage cuz 9 cal per gram)
2) phosopholipids impt for myelin sheaths
3) cholest stablilizing component of plasma membranes and is precursor of bile salts, steroid hormones, and other essential molecules
4) tryglyc--major fuel of skeletal muscle and hepatocytes
5) help absorb vitamins
31
multiple sclerosis
breakdown of myelin sheath
32
fat should be what percentage of caloric intake
30%
33
20 amino acids. How many are essential?
8
34
complete proteins
all 8 essential are present
35
incomplete proteins
not all 8 essential amino acids are present
36
protein provides material for your body to make
other proteins!
| and other non protein, nitrgoen-containing molecules
37
proteins serve as
structural molecules
contractile filaments of muscles
enzymes and hormones
38
whether food protein is used to build stuff or burnt for fuel is 3 things
all or none rule
adequacy of caloric intake
hormonal controls
39
all or none rule
All amino acids needed to make a particular protein must be present in a cell at the same time and in sufficient amounts. If one is missing, the protein cannot be made. Because essential amino acids cannot be stored, those not used immediately to build proteins are oxidized for energy or converted to carbohydrates or fats.
40
adequacy of caloric intake
not enough carbs or fats, protein will be burned instead
41
hormonal controls
various hormones help determine nitrogen balance
42
Nitrogen balance
nitrogen intake - nitrogen excretion (feces, urine)
43
balanced nitrogen
Rate of protein synthesis equals rate of protein breakdown
44
positive nitrogen balance
Protein incorporated into tissue > Protein breakdown for energy
(e.g., growing, pregnant women, tissue repair injury)
45
negative nitrogen balance
Protein incorporated into tissue < Protein breakdown for energy
(e.g., during emotional of physical stress, protein malnutrition, starvation)
46
how much protein for kg of body weight
0.8 g
47
recommended percentage of protein in caloric intake
20%
48
vitamins
Organic molecules needed in trace amounts
- -Most vitamins act as coenzymes, which are necessary for enzyme function
- -Most vitamins need to be obtained from food
Exceptions: Vitamin D (made in skin); small amounts of B and K made by gut bacteria
49
water soluble vitamins
B complex and C
Absorbed along with water in gastrointestinal tract
Exception: B12 requires intrinsic factor (secreted by stomach)
50
fat soluble vitamins
A, D, E, K
Absorbed along with lipids in GI tract
Fat-soluble vitamins (except K) are stored in the body; too many fat-soluble vitamins can cause toxicity!
51
why is it tough to overdose on vitamin B and C
they are water-soluble and the body eliminates excess amounts in about 1 hour (via urine)
52
don't need to know all the vitamins
okay
53
minerals
elements needed in trace amounts
4% of our body weight
ionized in body fluid/incorporated into organic molecules
54
when assoc. with an enzyme
vitamins are coenzymes
| minerals are cofactors
55
metabolism
sum of all biochemical reactions in the body
56
anabolism
“Building up” reactions; require input of energy
57
catabolism
“Tearing down” reactions; generate energy
58
3 stages of metabolism
1) digestion and absorption => transport to tissues
2) once inside cells, nutrients
--made into lipids, proteins, glycogen, etc. via anabolic paths
--broken down into pyruvate and acetyl-CoA via catabolic pathways
3) catabolic pathway chosen--nutrient into mitochondria to complete breakdown, releasing a lot of ATP
term cellular respiration refers to last part of 2 and 3
59
study chart 26
yes
60
LEO: Lose electrons (and energy) => Oxidized
GER: Gain electrons (and energy) => Reduced
61
Redox enzymes usually require a coenzyme derived from
B vitamin (e.g., NAD+ or FAD)
62
Glycolysis
produces Small amounts of ATP are produced (substrate-level phosphorylation)
happens in cytosol
63
point of glycolysis
Produce pyruvic acid (pyruvate), depends on O2:
If oxygen is present => Citric acid cycle (as acetyl-CoA)
If oxygen is absent => Fermentation (lactic acid)
64
KNOW SLIDE 28
yes
65
citric acid cycle
fed by pyruvic acid
some incidental ATP made (substrate-level phosphorylation)
extract hydrogens and electrons, burning glucose and emitting co2 as a waste product
point: fully oxidize the fuel
66
all of cells' metabolism is oriented towards
citric acid cycle
67
electron transport chain
electrochemical gradient made, H+ want to rush in
ADP and phosphate smash together to make ATP
waste products=carbon dioxide and water
68
glycolysis=>citric acid cycle=>electron transport chain
yes
69
at rest, 100 kcal
per hour
70
1 mole of glucose has 686 cal, and aerobic resp can capture how many in atp
262 cal
| energy efficiency than 38%, more efficient than car engines
71
don't need to know energy payoff at each step
no
72
how many ATP made?
30 ATP molecules
73
Glycolysis--carb metabolism slide
Glucose => Pyruvic acid
Most glucose => ATP
But, cells cannot store ATP, if too much glucose store as glycogen or fat
Most stored energy (80-85%) is as fat
74
Glycogenesis
Glucose => Glycogen
process of storing glucose
Mostly occurs in liver and skeletal muscle
75
Glycogenolysis
Glycogen => Glucose
| Occurs in liver when blood glucose levels drop
76
Gluconeogenesis
Other stuff => Glucose
Non-carbohydrate (e.g., proteins) converted to glucose (liver)
So even if you eat a low-carb diet, your body makes glucose to ensure your neurons don’t die!
77
only BLANK routinely used as fuel
triglycerides
78
lipolysis
Triglyceride => Fatty acids + glycerol
| Glycerol into glycolytic pathway
79
Fatty acids undergo
beta oxidation, creates NADH and acetyl-CoA (which enters citric acid cycle)
80
lipogenesis
Cell makes fatty acids from acetyl-CoA and combines them with glycerol to make triglycerides
Even on low-fat diet, your body makes fat!
81
about 1/2 fat made in your body
subcutaneous
82
if glucose and ATP levels high
cell makes lipids
83
if carb intake insufficient
body will burn fat
84
ketoacidosis
metabolism out of whack
extremely low carb diet
blood can become too acidic
85
protein metabolism
limited lifespan in body
if more than needed, burned for energy or converted to glucose or fat
first, amine group must be removed (deaminated) before being metabolized
Ammonia (NH3) is toxic waste product of protein metab
--combined with 02 to make urea
86
Which organ makes nonessential amino acids
liver
87
Absorptive state (5)
lasts about 4 hrs after eating
Anabolism > Catabolism
1) Nutrients stored
2) Glucose=major fuel
3) Dietary protein and fat replace the used up protein and fat; small amounts burned for ATP
4) Excess metabolites converted to fat
5) Rising insulin levels direct all of the above processes
Recall: When blood glucose levels rise, insulin helps bring those levels back down by helping cells absorb it
88
Postabsorptive state
glucagon dominates
Stores broken down for energy
Primary goal is maintain blood glucose levels by:
Making glucose available to blood
Glycogenolysis, gluconeogenesis
Blood glucose level regulation more complex than when eating:
Less insulin and more glucagon released
Sympathetic nervous system stimulates glycogenolysis
Fasting and exercise both result in a similar metabolic profile
89
glucose sparing:
Lipolysis followed by forcing other organs to use fats instead of glucose (which is saved for the brain)
90
liver produces about
80% body's cholesterol--restricting doesn't do much
high saturated fat diet stimulates the body produce and retain cholesterol, while a diet high in unsaturated fats has the opposite effect
91
First Law of Thermodynamics: Energy can be transformed, but it cannot be destroyed. This also applies to your body:
Energy intake = Energy output (heat + work + energy storage)
Almost all energy from food eventually lost as heat
Even if ATP made, the body’s use of ATP causes heat loss
Everything our body does (move, blood flow, etc.) causes heat loss
But that’s okay! We need our body temperature to stay around 98.6° F for our metabolism
