Nutrition and Metabolism Flashcards
(145 cards)
1
Q
Weight is determined by_____
A
the bodies energy balance
2
Q
What type of hormones are involved in appetite control?
A
peptide hormones
3
Q
What are the two types of appetite controlling hormones?
A
- Short term
- long term
4
Q
What are short-term regulators of appetite?
A
- Hormones that work over a period of minutes or hours
- Makes you hungry when you begin eating
- make you satiated when you end a meal
5
Q
What are the four main short-term appetite regulating hormones?
A
- Ghrelin
- Peptide YY
- Cholecystokinin
- Amylin
6
Q
What is the function of ghrelin? where does it come from?
A
- From the parietal cells of the fundus of an empty stomach
- Promotes hunger
- stimulates the secretion of GHRH to absorb nutrients
- stops an hour after feeding
7
Q
What is the source and function of peptide YY (PYY)?
A
- Enteroendocrine cells of the ileum and colon after food is detected in the stomach
- Signals satiety and terminate eating
8
Q
What is the source and function of Cholecystokinin (CCK)?
A
- Enteroendocrine cells in duodenum and jejunum
- stimulates secretion of bile and pancreatic enzymes
- suppresses appetite
9
Q
What is the source and function of amylin?
A
- Beta cells of pancreas
- inhibits stomach activity and produces satiety
10
Q
What two peptides inform the brain of how mmuch adipose tissue the body has?
A
Leptin and insulin
11
Q
Where in the brain do the appetite hormones act?
A
The arcuate nucleus of the hypothalamus
12
Q
How does the hypothalamus act on appetite?
A
Via two different neural networks. One to stimulate and one to inhibit
13
Q
What hypothalamic peptide is responsible for stimulating appetite?
A
Neuropeptide Y (NPY)
14
Q
What hormones stimulate neuropeptide Y?
A
Grelin
15
Q
What hormones inhibit neuropeptide Y?
A
insulin, PPY, and leptin
16
Q
What hypothalamic hormone is responsible for inhibiting eating?
A
melanocortin
17
Q
What hormones stimulate melanocortin?
A
Leptin
18
Q
What hormones inhibit appetite stimulants?
A
endocannabinoids
19
Q
Hunger is also stimulated by gastric ____
A
peristalsis
20
Q
A person is obese when they weigh more than ___% above norm
A
20
21
Q
How is bmi calculated?
A
W/H(squared)
22
Q
how many kcal/g does alchohol provide?
A
7.1
23
Q
What is a nutrient?
A
Any ingested chemical used for growth, repair, or maintenance
24
Q
wHAT ARE THE 6 CLASSES OF NUTRIENTS?
A
Water, Carbs, lipids, protein, vitamins, minerals
25
What is an essential nutrient?
one that cannot be synthesized by the body
26
What are the main functions of carbs as a nutrient?
- Act as structure for molecules
| - serve as a main fuel source
27
Carb intake influences ___ of other nutrients
Metabolism
28
How many grams of glucose does the brain use a day?
120g
29
What is dietary fiber?
all fibrous material of plant and animal orgin that resists digestion
30
What are the two types of dietary fiber?
Soluble and insoluble
31
What are the benifets of soluble fibers?
they decrease LDL levels
32
What can ow levels of fat intake cause a vitimine deficiency?
Because lipid soluble vitamins rely on fat for absorption
33
What are the four functions of fat?
- Energy
- Structure of phospholipids and plasma membranes
- Chemical precursors
- protection and insulation
34
Fat should make up less than ___ of daily calorie intake
35%
35
How are lipids transported in plasma?
Via lipoprotein complexes
36
What are lipoprotein complexes?
Tiny droplets with a core of cholesterol and triglycerides all with a protein coat
37
How are lipoproteins classified? how many classifications are there?
- By density
| - 4
38
What are the four lipoproteins?
- VLDL
- LDL
- HDL
- Chylomicrons
39
Where do VLDL's come from and what is their function?
- Come from the liver
- Transport lipids to adipose tissue
- Become LDL's after they transport
40
What two ways does the body use LDL's
- Absorbed by cells in need of cholesterol
| - Digested to release cholesterol for intercellular use
41
WHat is the function of HDL's?
- They start as an empty shell
- The travel through the blood and pick up cholesterol and phospholipids
- Pass picked up lipids to the liver for elimination
42
High LDL's levels correlate with___
cholesterol deposition in arteries
43
RDA for protein is
46-56 g/day
44
How many amino acid are essential?
8
45
How many amino acids are inessential?
12
46
What is net protein utilization?
the percentage of amino acids in a protein that the human body uses
47
What is nitrogen balance?
The rate of nitrogen ingested equals nitrogen excreted
48
When does a positive protein balance occur?
When nitrogen ingestion exceeds its excretion
- Childhood
- Pregnancy
- excess growth hormone and sex steroids
49
When does a negative nitrogen balance occur?
During starvation and stress
50
What are minerals?
Inorganic eements that plants extract from soil or water
51
What are vitamins?
dietary organic compounds that are necessary for metabolism
52
Gross function of phosphorus?
Structural component and component of phosphate buffer system
53
Gross functions of calcium, iron, magnesium, and manganese?
they act as cofactors for enzymes
54
Main function of chlorine?
component of stomach acid
55
What four vitimins can the body synthesize from provitimins?
Niacin
Vit. A
Vit. D
Vit. K, pantothenic acid, biotin, folic acid produced from bacteria
56
What is the function of oxidative carbohydrate metabolism?
To transfer energy from glucose to ATP
57
What are the three major pathways of glucose catabolism?
- Glycolysis
- Anaerobic fermentation
- Aerobic respiration
58
WHat is glycolysis?
when a glucose is split into two pyruvate molecules
59
What is anaerobic fermentation?
When pyruvate is reduced to lactate in the absence of oxygen
60
What is aerobic fermentation?
Pyruvate is oxidized into CO2 and H2O
61
What are the two major co-enzymes in glucose catabolism?
NAD+-from niacin
| and FAD-from riboflavin
62
What is added to NAD+ to become NADH?
2H combinds with one NAD+ and results in on NADH and one H+
63
What is added to FAD to make FADH2
2H is added
64
What is the first step of glycolysis?
Phosphorylation
65
What is phosphorylation?
When ATP donates a phosphate group to a glucose to produce glucose 6-phosphate
*facilitated using the hexokinase enzyme*
66
What is the next step in glycolysis after Phosphorylation?
Priming
67
What occurs during the priming stage of glycolysis?
2 ATP's are used to rearrange G6P (becomes isomerized)
68
What occurs after priming in glycolysis?
Cleavage
69
What occurs during the cleavage stage in glycolysis?
six carbon G6P is cleaved into three carbon compounds
70
What occurs after the cleavage stage in glycolysis?
Oxidation
71
What occurs during the oxidation stage of glycolysis?
- Each 3 carbon compound is oxidized by removing a pair of hydrogen and attaching them to NAD+ to make NADH
- A phosphate group is added to each carbon fragment
72
What occurs after oxidation in glycolysis?
Dephosphorylation
73
What occurs during dephosphorylation?
- Phosphate groups are removed from carbon fragments and added to ADP to make ATP
- 3 carbon compounds become pyruvate
74
How much ATP is netted from glycolysis?
2 ATP per glucose
75
What are the end products of glycolysis?
- 2 pyruvate
- 2 NADH
- 2 ATP
- 2 H+
76
What is the fate of pyruvate after glycolysis?
anarobic fermentation or aerobic respiration depending on oxy. availability
77
What are the two principal steps of aerobic respiration?
- Matrix reactions-controling enzymes in fluid of mitochondria
- Membrane reactions-enzymes bound to membranes of mitochondria
78
What is the first step in the matrix reactions of aerobic respiration? what occurs during this step?
- The transition step
| - Pyruvate is prepared to enter citric acid cycle
79
What happens to pyruvate during the transition step?
CO2 is removed, NAD+ removes hydrogen atoms and a coenzyme is added to make Acetyl-coenzyme A (Acetyl-CoA)
80
What occurs after the transition step?
The citric acid cycle begins
81
What occurs during the citric acid cycle?
- A series of reactions that take starts with acetyl-CoA combinding to make citric acid
- That citric acid continues to donate carbons producing NADH
- as well as producing ATP and FADH before it start again
82
The electron transport chain is a ___ reaction
Membrane
83
What are the two purposes of membrane reactions?
To further oxidize NADH and FADH2 and turn them into ATP
84
What is the mitochondrial electron transport chain?
series of
| compounds that carry out this series of membrane reactions To further oxidize NADH and FADH2 and turn them into ATP
85
What is the final electron acceptor in the electron transport chain?
Oxygen
86
How are NADH and FADH formed into ATP?
The H+ are transported from the matrix space of the mitochondria to a space between the membranes.
-This creates a H+ graident and causes an influx of H+ back into the matrix.
This influx creates energy that produces ATP
87
What is the total amount of ATP generated by one glucose molecule via oxidation of glucose?
32
88
What is Glycogenesis?
The synthesis of glycogen
89
What stimulates glycogenesis? what occurs?
- Insulin stimulates it
| - It occurs by the chaining of glucose monomers
90
What is glycogenolysis?
The hydrolysis of glycogen
91
When is glycogenolysis occur and what stimulates it?
- between meals to release glucose
| - Glucagon and epinephrine stimulate it
92
Where i the glucose released back into the blood after glycogenolysis?
the liver
93
What is gluconeogenesis? where does it occur?
- The synthesis of glucose from noncarbohydrates such as glycerol and amino acids
- occurs in the liver
94
What form is fat stored in the body and where is it stored
As triglycerides in adipocytes
95
What is lipogenesis?
The synthesis of fat from other types of molecules
96
What molecules can be combined to make fat?
- Amino acids and sugars
- glucose
- Acetyl-CoA uses to make fatty acids
97
Lipid metabolism begins with the ____ of ____(stored fats)
Hydrolysis of Triglycerides
98
What is the product of triglyceride hydrolysis?
Glycerol and fatty acids
99
What happens to the glycerol product of triglyceride hydrolysis?
it is added to the pathway of glycolysis to produce ATP *only half as much as glucose*
100
What happens to the fatty acid product of triglyceride hydrolysis?
- Beta oxidation in the Mitochondrial matrix
| - 2 carbon atoms bind to coenzyme a to make acetyl-CoA
101
What is the fate of the acetyl-CoA produced by lipid metabolism?
- Used in the krebs cycle
| - metabolized by the liver to produce ketone bodies
102
what must happen first In order for the body to use amino acids directly as fuel?
they must first be deaminated
| removal of -NH2
103
How is the amino acid used after it is deaminated?
it is converted into pyruvate, acetyl-CoA, or an acid in the citric acid cycle
104
What is the metabolic source of ammonia?
- When amino acids are deaminated it is converted into glutamic acid
- In the live the glutamic acid has its -NH2 removed
- The NH2 becomes NH3 (ammonia)
- Liver combines NH3 with CO2 to produce urea
- Urea is excreted from the body in urine
105
What is an absorptive state?
It is a fed state
106
How long does the absorptive state last?
about 4 hours after meal
107
What is occuring in an absorptive state?
Nutrients are being absorbed and may be used immediately to meet energy needs
108
What is a postabsorptive state?
A fasting state
109
What is occuring during a postabsorptive state?
- Stomach and intestines are empty
| - Body meets energy needs with stored fuel
110
What is the major source of fuel in an absorptive state?
Dietary glucose
111
The major metabolic thrust during an absorptive state is___
anabolism of energy storage
112
What happens to amino acids in an absorptive state?
they become proteins
113
What happens to glycerol and fatty acids in an absorptive state?
They are converted into triglycerides
114
What happens to excess amino acids in an absorptive state?
They are deaminated and used for energy or stored as fat in the liver
115
What is the major regulator of the absorptive state?
Insulin
116
What is the major etabolic thrust during a postabsorptive state?
the catabolism and replacement of fuels in the blood
117
What happens to proteins during a postabsorptive state?
The are broken down into amino acids
118
What happens to Triglycerides during a postabsorptive state?
They are turned into glycerol and fatty acids
119
What happens to glycogen during a postabsorptive state?
it becomes glucose
120
What are the major energy fuel's in a postabsorptive state?
Fatty acids and ketones
121
What is the main regulator of the postabsorptive state?
the sympathetic nervous system and glucagon
122
The metabolic rate is defined as-
The amount of energy liberated in the body in a given period of time
123
How is metabolic rate directly measured?
with a calorimeter
124
How is metabolic rate indirectly measured?
a spirometer measuring the amount of oxy a person uses
125
What is the basal metabolic rate?
– A baseline or standard of comparison that minimizes the effects of activity, feeding, and hormone levels
126
What is the total metabolic rate?
The sum of the BMR and energy expenditures for voluntary activities
127
What is thermoregulation?
—the balance between heat
| production and loss
128
Why is thermotegulation so important?
Because the enzymes in the body depend on an optimal, stable working temp.
129
The best estimate of core body temperature is from the-
rectum
130
What is average core body temp
99.0-99.7
131
What is shell temperature?
The temperature closer to the surface (oral temp, skin temp)
132
Where does most of the body's heat come from?
Exergonic chemical reactions such as nutrient oxidation and ATP usage
133
What are the four ways the body loses heat?
1. Infrared radiation via moving moecules
2. Conduction of heat from the body to things touching it
3. convection of heat to moving fluids
4. Evaporation
134
How is thermoregulation achieved?
via negative feedback loops
135
What is the hypothalamic thermostat?
The preoptic portion of the hypothalamus that functions as the body's thermostat
136
How does the hypothalamic thermostat monitor body temp
through the monitoring of blood temp via signals from the peripheral thermoreceptors in the skin
-sends signals to appropriate centers
137
What is the heat-loss center of the brain?
In the anterior hypothalamus
138
Where is the heat-promoting center of the brain?
near the mammillary bodies of the brain
139
What occurs when heat-loss centers activate in response to high blood temp?
- causes cutaneous vasodilation
- triggers sweating if needed
- inhibits heat-promoting center
140
What occurs when the heat-promoting center detects low blood temp
- Causes vutaneous vasoconstriction to retain warm blood deeper in the body
- causes shivering to produce heat
141
How is heat produced longterm?
Metabolic rate is increased
142
What is behavioral thermoregulation?
the adding or removal of clothing
143
What is fever
a normal protective mechanism that should be allowed
144
What are the three main dangers of prolonged heat exposure?
- Heat cramps-due to electrolyte imbalance from sweating
- Heat Exhaustion-from severe water and electrolyte loss
- Heat stroke- core body temp rises above 104
145
What occurs if core temp drops below 91 degrees
Hypothermis occurs
- metabolic rate drops so low that body cant maintain heat production
- causes more tempture drop
