nutrition, metabolism, and body temp (ch 23) Flashcards
(114 cards)
1
Q
what is a nutrient
A
a substance in food for growth, maintenance, and repair
2
Q
what are major nutrients
A
the bulk of ingested food
3
Q
major nutrients
A
carbohydrates, fat, protein
4
Q
what are micronutrients
A
things required in small amounts
5
Q
micronutrients
A
vitamins, minerals
6
Q
uses for nutrients
A
metabolic fuel
cell structure and molecular synthesis
7
Q
energy value is measured by
A
kcal = Calorie = heat energy needed to raise 1L H2O by 1C
8
Q
food groups
A
fruit, vegetables, grain, protein, dairy, oil
9
Q
what converts molecules into those needed to live
A
the liver
10
Q
what are essential nutrients
A
the approximately 50 molecules that the diet must provide - cannot be synthesized by the liver
11
Q
dietary sources of carbohydrates
A
primarily plants (starch, sugars, fiber)
some animal sources (glycogen)
12
Q
starches are
A
complex carbs - lots of sugars strung in a long chain
13
Q
sugars are
A
mono and disaccharides
14
Q
fibers are
A
not digestible because we lack the necessary enzymes (insoluble - cellulose, soluble - pectin)
15
Q
carbohydrate examples in food
A
starch - vegetables and grains
sugars - milk, fruit, cane sugar
insoluble fiber - green vegetables
soluble fiber - fruits, oats
16
Q
carbohydrate use in body
A
glucose - major energy fuel used by cells to assemble ATP
17
Q
which cells can only use glucose for energy
A
neurons and RBCs
18
Q
what happens to excess glucose
A
it is converted to glycogen or fat and stored
19
Q
what can be converted to glucose
A
fructose and galactose
20
Q
recommended intake of carbohydrates
A
45-65% of total caloric intake, mostly complex (fruits, vegetables, grains)
21
Q
highly refined carbohydrates can cause
A
obesity, chronic disease, increased risk of type 2 diabetes
22
Q
difference between saturated and unsaturated fats
A
saturated - lack of double bonds, animal sources (meat/dairy), solid at room temp
unsaturated - at least one double bond, plant oil/nut sources
23
Q
where can cholesterol come from
A
egg yolk, meats, organs, shellfish, milk products
ALSO, liver makes around 85% of necessary cholesterol
24
Q
what are essential fatty acids
A
fatty acids that cannot be made by the liver from other fats
25
essential fatty acid examples
linoleic and linolenic acid (found in most veg oils)
26
function of lipids (general)
major fuel source for liver and muscle cells
27
function of phospholipids
component of cell membranes
28
function of adipose tissue
energy stores, cushioning
29
function of prostaglandins
inflammation, smooth muscle contraction
30
function of cholesterol
important for membranes, bile, and hormones
31
dietary recommendations for fats per the AHA
fats - 30% or less of total caloric intake
cholesterol - less than 200 mg/dL in blood
32
what are complete proteins
proteins containing all essential amino acids (animal sources)
33
what are incomplete proteins
proteins that do not contain all essential amino acids (plant protein)
34
can the body produce essential amino acids
no
35
how to get all essential amino acids without animal products
combine grains/cereals (grasses) with legumes (beans)
36
which proteins are used as structural materials in the body
insoluble fibers (collagen, elastin, actin, myosin)
37
which proteins are used as functional molecules in the body
soluble proteins (enzymes, hormones, antibodies)
38
protein can be used as ______ when there is not enough ___________ available
an alternative energy source, carbohydrates or fats
39
all amino acids must be present for _______
adequate protein synthesis
40
all amino acids contain _______
nitrogen
41
positive nitrogen balance
when synthesis exceeds breakdown - to grow there needs to be extra amino acids
(occurs in instances of growing muscle, pregnancy, and kids)
42
negative nitrogen balance
when breakdown exceeds synthesis - growth does not occur (cases of starvation, sedentary individuals, elderly)
43
anabolic hormones such as GH and sex hormones
induce protein synthesis
44
adrenal glucocorticoids (released during stress)
catabolize/breakdown protein to use as fuel
45
dietary requirements for protein
needs reflect age, size, metabolic rate, nitrogen balance (but the typical American diet provides plenty of protein)
46
organic compounds of vitamins
carbon and hyrogen
47
functions of vitamins
helping body use nutrients
coenzymes (works with enzymes in chemical reactions)
48
non-food sources of vitamins
D - skin
B and K - synthesized by intestinal bacteria
A - converted from beta-carotene
49
characteristics of water soluble vitamins
all B vitamins, vitamin C
absorbed with water
not stored in body (goes quickly through urine)
50
B12 absorption requires
intrinsic factor (parietal cells to be secreted by stomach cells)
51
characteristics of fat-soluble vitamins
vitamins A, D, E, and K
stored in body, except for vitamin K
high levels are toxic
52
how is vitamin K produced
by bacteria in the large intestine
53
function of antioxidants/example
picking up electrons in the body, neutralize free radicals (vitamins C, A, E)
54
what are free radicals
chemicals with extra electrons that mainly damage proteins
55
minerals are
inorganic materials/ions, mainly metals
56
minerals required in moderate amounts/how much
greater than 200 mg/day of the following: calcium, phosphorus, sulfur, potassium, chlorine, sodium
57
minerals required in trace amounts
iron, fluorine, zinc, copper, iodine, maganese
58
function of mineral
working with nutrients to ensure proper body function
59
how is mineral toxicity prevented
uptake and excretion are balanced
60
function of calcium and phosphorus
needed for bones
61
function of iron
essential for heme in hemoglobin
62
function of iodine
necessary for T3/T4 thyroid hormone synthesis
63
sodium, chloride, and potassium are all
major electrolytes
64
metabolism is
biochemical reactions inside cells that involve nutrients (how we get energy)
65
types of metabolic reactions
anabolism - synthesis of large molecules from small (energy in)
catabolism - breakdown of complex structures to simpler ones (energy out)
66
examples of metabolic reactions
anabolism: amino acids --> protein
catabolism: food + O2 --> CO2 + H2O + energy
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cellular respiration
the catabolism/oxidization of food to fuel, captures energy to form ATP from ADP + phosphate
68
phosphorylation
when a molecule gives a phosphate group to another, giving them the energy to perform cell activities that require energy
69
stages of metabolism in processing nutrients
digestion, absorption, and transport to tissues
cellular processing (in cytoplasm)
70
how is food oxidized for fuel
pairs of hydrogen atoms are removed from food step by step, then the pairs combine with oxygen to form H2O
71
types of cellular respiration
glycolysis, Krebs (citric acid) cycle, oxidative phosphorylation
72
oxidized vs reduced substances
oxidized - loses electrons or hydrogen, and energy
reduced - gains electrons or hydrogen, and energy
73
characteristics of redox reactions
catalyzed by enzymes (often require help from coenzymes)
74
characteristics/examples of coenzymes
acts as hydrogen or electron acceptors
ex: vitamin B derivatives (B3 niacin, B2 riboflavin), NAD+ (from niacin), FAD (from riboflavin)
75
substrate level phosphorylation
type of ATP synthesis in which high-energy phosphates are directly transferred to ADP
76
oxidative phosphorylation
more complex type of ATP synthesis, produces most ATP
77
oxidative phosphorylation process
direct (usually in cytoplasm) - energy is used to pump H+ across the inner mitochondrial membrane
indirect (mitochondria) - H+ flows back through ATP synthase membrane channel, energy is used to phosphorylate ADP
78
complete glucose catabolism requires three pathways
glycolysis
Krebs cycle
electron transport chain and oxidative phosphorylation
79
characteristics of glycolysis
10 steps, anaerobic, occurs in cytosol
glucose --> two pyruvates
produces ATP faster than aerobic respiration
yields far less ATP (1 glucose : 2 ATP)
80
glycolysis steps
if no oxygen present, NADH gives H+ back to pyruvic acid, reducing it to lactic acid
lactate leaves the cell and goes to the liver
may be converted back to glucose for release into blood or for storage as glycogen
81
characteristics of the Krebs cycle
occurs in the mitochondrial matrix
fueled by pyruvic acid
1 glucose : 2 pyruvic acid molecules (2 Krebs cycles)
82
Krebs cycle steps
pyruvic acid loses one carbon to form acetyl group
then combines with coenzyme A to form acetyl-coenzyme A
coenzyme A takes acetic acid to Krebs cycle
acetyl-coenzyme A combines with oxaloacetic acid to form citric acid
two carbons are removed as CO2 and energy is passed to ATP, NACH + H+, and FADH2
oxaloacetic acid is regenerated
83
characteristics of the electron transport chain and oxidative phosphorylation
directly uses oxygen
NADH + H+ and FADH2 have hydrogen
1 glucose : 30 ATP
84
electron transport chain and oxidative phosphorylation steps
hydrogen atoms combine with O2 to form H2O
released energy is given to ATP by oxidative phosphorylation
85
characteristics of lipid metabolism
greatest energy yield of the macromolecules
glycerol pathway - sugar enters glycolysis to Krebs
fatty acid pathway - chains broken off in two carbon fragments and enters the Krebs cycle
86
a lack of carbohydrate in one's diet leads to
lots of acetyl CoA and ketones
87
characteristics of protein metabolism
proteins are continuously broken down and replaced - amino acids are recycled for new proteins or another compound, or oxidized for energy or converted to fat for storage
88
how are amino acids oxidized
first deaminated (NH2 removed), then most are converted to various chemicals of the Krebs cycle
most nitrogen waste is converted into urea by the liver and excrete in the urine
89
metabolic rate
total heat produced by chemical reactions and friction within the body
90
basal metabolic rate
minimum number of chemical reactions needed to live
91
what influences BMR
body surface area ration, age, gender, body temperature, stress, thyroxine (T3/T4)
92
at rest, how is heat produced
organs - heart, liver, brain, kidney
93
during exercise, how is heat produced
muscles
94
normal body temperature is
37C or 98F
95
why is a body temperature of 37C needed
optimal range for body enzyme activity (increased temperature denatures enzymes)
children under five have seizures at 41C
limit for life: 43C
96
tissues may tolerate ________
low body temperatures
97
core vs shell temperature
core temp - highest/most constant
shell (skin) temp - usually lower, fluctuates between 20-40C
98
mechanisms of heat exchange with the environment
radiation
conduction
convection
evaporation
99
radiation
heat exchange through infrared rays
100
conduction
heat exchange through direct contact
101
convection
heat exchange through air movement
102
evaporation
heat exchange through water converting into gas
103
______ heat loss accompanies ______ water loss
insensible
104
insensible vs sensible heat loss
insensible - lungs, mucous membranes, skin (sweat)
sensible - when body temperature rises and you sweat (aware)
105
the ______ region of the hypothalamus receives afferent input from ______
preoptic, peripheral (skin) and central (deep) thermoreceptors
106
after receiving afferent input, the hypothalamus initiates
involuntary heat-loss and heat-promoting activities
107
types of heat-promoting mechanisms
constriction of BVs in extremities and skin
shivering
increased metabolic rate via epinephrine and NE
chemical thermogenesis
adipose tissue thermogenesis
enhanced thyroxine release
108
types of heat-loss mechanisms
dilation of cutaneous BVs, increasing blood to extremities and skin
sweating
109
hyperthermia
increased core body temperature
110
characteristics of heat exhaustion
collapse usually after vigorous exercise
dehydration with decrease in BP
heat-loss mechanisms still functioning
111
heat stroke begins at a core body temperature of _____C
41
112
characteristics of heat stroke
positive feedback mechanism (makes issue worse)
sweat stops - skin hot and dry
organs damages through denatured proteins
if not corrected, can lead to coma or death
113
characteristics of a fever
controlled hyperthermia
macrophages release cytokines/pyrogens that cause fever
damaged tissues release prostaglandins that reset the hypothalamic thermostat
114
characteristics of hypothermia
low body temperature due to exposure
vital signs decrease
at core temperature of 30-32C, shivering stops
loss of judgement --> coma --> death at 21C by cardiac arrest
