ch 26 nutrition Flashcards
(167 cards)
1
Q
What is nutrition?
A
–The source of fuel that provides energy for all biological work
–The source of raw materials for replacement of worn-out biomolecules and cells
2
Q
what is metabolism?
A
Sum of anabolism and catabolism
3
Q
Gain weight if
A
–if intake exceeds output
4
Q
–Lose weight
A
if output exceeds intake
5
Q
Determining factor in weight
A
Bodies energy balance
If energy intake and output are equal, body weight is stable
6
Q
What percentage of body wieght is hereditary?
A
30-50%
7
Q
Two types of appetite regulators
A
Short -term and Long-term
8
Q
Name the short term regulators
A
- ghrelin
- Peptide YY
- cholecystokinin (CKK)
9
Q
Properties of ghrelin
A
- Secreted from parietal cells in fundus of empty stomach
- Produces sensation of hunger
- Ghrelin secretion ceases within an hour of eating
10
Q
Peptide YY (PYY)
A
11
Q
What is the effect of Cholecystokinin (CCK) on digestive system
A
acts as a signal to stop eating
12
Q
Main function of short term regulators
A
–Mechanisms work over periods of minutes to hours
–Makes one feel hungry and begin eating
–Makes one feel satiated and end a meal
13
Q
Main function of long term appetite regulators
A
govern caloric intake and energy expenditure over periods of weeks to years
14
Q
Name the Long term appetite regulators
A
Leptin
Insulin
15
Q
Role of Leptin
A
Informs brain on how much body fat we have
16
Q
Role of insulin in appetite
A
- Stimulates glucose and amino acid uptake
- Promotes glycogen and fat synthesis
17
Q
Which are the two neural networks involved in hunger?
A
Neuropeptide Y group
Melanocortin group
18
Q
What is the umbrella term for the chemical signals from the gastrointestinal tract to the brain
A
Gut-brain peptides
19
Q
What is the function of neuropeptide Y
A
Potent appetite stimulant
20
Q
What is the function of melanocortin
A
inhibits eating
21
Q
Which appetite regulators stimulate neuropeptide Y?
A
Ghrelin
22
Q
Which appetite regulators inhibit neuropeptide Y?
A
Insulin
PYY
Leptin
23
Q
Which appetite regulator stimulates melanocortin?
A
Leptin
24
Q
What nuvleus of the hypothalamys has receptors for all 5 chemical signals?
A
Arcuate nucleus
25
What effect does gastric peristalsis have on hunger?
It stimulates hunger
26
Appetite is breifly satisfied by which physical signals
* Chewing and swallowing
* Stomach filling
27
Which type of food does the neurotransmitter epinephrine stimulate desire for?
–carbohydrates
28
Which type of food does the neurotransmitter Galanin stimulate desire for?
Fats
29
Which type of food does the neurotransmitter endorphons stimulate desire for?
Proteins
30
What is defined as obese?
weight more than 20% above recommended norm for one’s age, sex, and height
31
What is the optimal range for BMI?
20-25
32
What is the formula for BMI?
–BMI = W/H2 (W = weight in kg; H = height in meters)
33
Effects of obesity
increased risk of
* atherosclerosis
* hypertension
* diabetes mellitus
* joint pain,
* kidney stones
* gallstones
* cancer of uterus, breast, and prostate
* sleep apnea
34
How many calories is a kilocalorie?
1000
35
How many kcal do Carbs and proteins yield?
4 kcal
36
How many kcal do fats yield?
9kcal/g
37
What type of calories are sugar and alcohol?
'empty'
38
What is One calorie?
amount of heat required to raise temperature of 1 g of water 1°C
39
What is a nutrient?
any ingested chemical used for growth, repair, or maintenance of the body
40
What are the six classes of nutrients?
* Water
* Carbohydrates
* Lipids
* Proteins
* Vitamins
* Minerals
41
What are macronutrients?
nutrients that must be consumed in relatively large quantities
42
Which are the macronutrients?
Water, Carbohydrates, Lipids, proteins
43
What are Micronutrients?
44
Which are the micronutrients?
Vitamins and minerals
45
What are Essential nutrients?
Nutrients that cannot be synthesized in body
46
How many grams of carbohydrates does a well nourished adult body have?
440g
47
How do sugars function in the body?
As structural components of molecules in the body
As fuel
48
What is hypoglycemia?
Deficiency of blood glucose
49
What is the Blood glucose concentration?
A carefully regulated interplay of insulin and glucagon
50
How does Carbohydrate intake influence the metabolism of other nutrients?
–Fats used as fuel when glucose and glycogen levels are low
–Excess carbohydrates are converted to fat
51
What are the three principle forms of dietary carbohydrates?
Monosaccharides
Disaccharides
Polysaccharides
52
Name the monosaccharides
–glucose, galactose, fructose
53
Name the Disaccharides
sucrose (table sugar), maltose, lactose
54
Name the Polysaccharides (complex carbohydrates)
starch, glycogen, and cellulose
55
What is the Glycemic index (GI)
effect of a dietary carbohydrate on blood glucose level
56
What is the effect of high-GI carbohydrates?
stimulate a high insulin demand and raise the risk of obesity and type 2 diabetes mellitus
57
What are the two types of fiber?
Water soluble fiber
Water in-soluble fiber
58
Name the dietary fibers
Cellulose, pectin, gums, and lignins
59
•Well-nourished adult meets what percentage of resting energy needs from fat
80%-90%
60
Which are the fat soluble vitamins?
A,D,E,K
61
What are the other functions of lipids?
–Structural
–Chemical precursors
–Important protective and insulating functions
62
Which fats have structural functions?
Phospholipids and cholesterol
63
Which fats are chemical precursors?
* Cholesterol
* Thromboplastin
* Fatty acids
64
Main sources of dietary fats
Saturated fats
unsaturated fats
cholesterol
65
Why are lipids an important part of the diet?
–Must be transported to all cells of the body
–Are hydrophobic and do not dissolve in blood plasma
66
What is the function of Lipoprotein complexes?
transport lipids in plasma
67
What are the four categoreis of serum lipoproteins?
* Chylomicrons: 75–1,200 nm in diameter
* Very low–density lipoproteins (VLDLs): 30–80 nm
* Low-density lipoproteins (LDL): 18–25 nm
* High-density lipoproteins (HDL):
68
Where does HDL production begin?
In the liver
69
Name lipoprotein A
chylomicron
70
Name lipoprotein B
Very low–density lipoprotein
71
Name lipoprotein C
Low-density lipoprotein (LDL)
72
Name lipoprotein D
High-density lipoprotein (HDL)
73
What is the optimum plasma cholesterol concentration?
less than 200mg/L
74
What is considered pathalogical plasma cholesterol concentration?
240mg/L
75
Should you have a higher HDL or LDL?
HDL
76
What is are the functions of proteins in nutrition?
–Muscle contraction
–Motility of cilia and flagella
–Structural components
–Buffer pH of body fluids
–Contribute to resting membrane potential of all cells
77
What happens if an excess of protein is consumed?
Can cause kidney damage with nitrogenous waste
78
How many amino acids are essential (cannot be synthesized in the body)?
8
79
What are Complete proteins?
high-quality dietary proteins that provide all essential amino acids in the necessary proportions
80
what are Incomplete proteins?
lower quality proteins that lack one or more essential amino acids
81
What is Net protein utilization?
the percentage of amino acids in a protein that the human body uses
82
Is it considered to be healthier to eat more meat or plants?
Plants
83
Name some sources of complete proteins
Animal proteins of meat, eggs, and dairy products
84
Which are the incomplete proteins?
plant sources such as beans and rice
85
What is the chief dietary source of nitrogen?
Protein
86
What do we mean by Nitrogen balance?
rate of nitrogen ingested equals rate of nitrogen excreted
87
What is Positive nitrogen balance?
Nitrogen ingestion exceeds its excretion
88
What is Negative nitrogen balance?
Excretion exceeds ingestion
89
What are Minerals?
inorganic elements that plants extract from soil or water and introduce into the food web
90
What are Vitamins?
small dietary organic compounds that are necessary for metabolism
91
What is the role of minerals and vitamins in nutrition?
Both are essential to our ability to use other nutrients
92
Minerals constitute what percent of the body mass?
4%
93
Which mineral is a Key structural component of phospholipids, ATP, cAMP, GTP, and creatine phosphate, and the Basis for the phosphate buffer system
–Phosphorus
94
Which minerals function as cofactors for enzymes?
–Calcium, iron, magnesium, and manganese
95
Which mineral is essential for the O2-carrying capacity of Hb and myoglobin
Iron
96
Which mineral is a component of stomach acid?
chlorine
97
Which are the best sources of minerals?
vegetables, legumes, milk, eggs, fish, shellfish,
98
What are precursors to vitamins called?
provitamins
99
What can an elevated salt intake cause?
Hypertension
100
Which are the water soluble vitamins?
Vitamins B and C
101
How are Water-soluble vitamins ingested?
Absorbed with water in small intestine and quickly excreted by kidneys, not stored
102
How are Fat-soluble vitamins ingested?
Incorporated into lipid micelles in the small intestine and absorbed with dietary lipids
103
What is the function of vitamin A
* Component of visual pigments
* Promotes proteoglycan synthesis and epithelial maintenance
104
What is the function of vitamin D
•Promotes calcium absorption and bone mineralization
105
What is the function of vitamin K
Essential for prothrombin synthesis and blood clotting
106
What is the function of vitamins A and E
Antioxidants like ascorbic acid
107
What is the function of vitamin C
* Promotes Hb synthesis, collagen synthesis, and sound connective tissue structure
* An antioxidant that scavenges free radicals and possibly reduces the risk of cancer
108
What is the function of Vitamin B
* Function as coenzymes
* Assist enzymes
* Make it possible for enzymes to catalyze
109
What is the world’s most common vitamin deficiency
A
110
What is the result of a vitamin A deficiency?
•night blindness; dry skin, hair, and conjunctiva; cloudy cornea; and increased incidence of infections
111
What is Hypervitaminosis
excess of (fat-soluble) vitamin
112
What is this the formula for?
Glucose catabolism
113
What is glucose catabolism?
series of small steps, each controlled by a separate enzyme, in which energy is released in small manageable amounts, and as much as possible, is transferred to ATP and the rest is released as heat
114
What are the three major pathways of glucose catabolism?
Glycolysis
Anaerobic fermentation
Aerobis respiration
115
What is Glycolysis?
Glucose (6 C) split into two pyruvic acid molecules (3 C)
116
What is Anaerobic fermentation?
* Occurs in the absence of O2
* Reduces pyruvic acid to lactic acid
117
What is Aerobic respiration?
* Occurs in the presence of O2
* Oxidizes pyruvic acid to CO2 and H2O
118
What are the three stages of cellular respiration?
1. Glycolysis
2. PYRUVATE OXIDATION and the CITRIC ACID CYCLE
3. OXIDATIVE PHOSPHORYLATION
119
Where and when does glycolysis occur?
in the cytoplasm whether or not there is O2 present
120
What is the product of glycolysis?
•breaks down glucose into 2 molecules of pyruvate
121
What are the two phases of glycolysis?
–Energy investment phase
–Energy payoff phase
122
What happens after peruvate is produced via glycolysis?
pyruvate must be converted to acetyl Coenzyme A (acetyl CoA), which links glycolysis to the citric acid cycle
123
What must happen to peruvate before the citric acid cyle can begin?
pyruvate must be converted to acetyl Coenzyme A (acetyl CoA)
124
What is another name for the citric acid cycle?
the Krebs cycle
125
What happens during the Citric acid cycle?
it completes the break down of pyruvate to CO2 generating 1 ATP, 3 NADH, and 1 FADH2 per turn
126
What happens during During oxidative phosphorylation?
chemiosmosis couples electron transport to ATP synthesis
127
Describe the pathway of electron transport
* The electron transport chain is in the inner membrane (cristae) of the mitochondrion
* The carriers alternate reduced and oxidized states as they accept and donate electrons
* Electrons drop in free energy as they go down the chain and are finally passed to O2, forming H2O
128
Fermentation and anaerobic respiration enable cells to produce ATP without the use of..?
Oxygen
129
What are the two types of fermentation?
Alcohol fermentation
Lactic acid fermentation
130
What is the flow of energy in cellular respiration?
glucose → NADH → electron transport chain → proton-motive force → ATP
131
What percentage of the energy in a glucose molecule is transferred to ATP during cellular respiration, making ~32 ATP?
34%
132
pyruvate is converted to ethanol in which 2 steps?
–The 1st step releases CO2
–The 2nd step produces ethanol
133
Human muscle cells use what type fermentation to generate ATP when O2 is scarce
lactic acid
134
Which step does lactic acid fermentation lack that is found in alcohol fermentation?
The release of CO2
135
What type of fermentation is pictured?
Alcohol Fermentation
136
what type of fermentation is pictured?
Lactic acid
137
Cellular respiration produces how many ATP per glucose molecule?
32
138
fermentation produces how many ATP per glucose molecule
2 ATP
139
Name one similarity bewteen fermentation and Anaerobi/Aerobic respiration?
They all use glycolysis to oxidize glucose
140
Name two anabolic synthesis reactions
Glycogenesis
Gluconeogenesis
141
What is glycogenesis?
The synthesis of glycogen by polymerizing glucose
142
What is gluconeogenesis
The synthesis of glucose from noncarbohydrates such as glycerol and amino acids
143
Name two catabolic breakdown reactions
Glycolysis
Glycogenolysis
144
What is Glycolysis?
the splitting of glucose into two molecules of pyruvic acid in preperation for anaerobic fermentation or aerobic respiration
145
Why is Glycogenolysis?
The hydrolysis of glycogen to release free glucose or glucose 1 phosphate
146
Where are Triglycerides are stored?
in body’s adipocytes
147
What is Lipogenesis?
synthesis of fat from other types of molecules
148
What is Lipolysis?
breaking down fat for fuel
149
What does Beta oxidation in the mitochondrial matrix do?
catabolizes the fatty acid components
150
What are the three methods of amino acid conversion?
* Deamination
* Amination
* Transamination
151
How does Deamination convert amino acids
removal of an amino group (−NH2)
152
How does Amination convert amino acids?
addition of −NH2
153
What is Transamination?
transfer of −NH2 from one molecule to another
154
what must happen to all amino acids before they can be used as fuel?
Must be deaminated
155
What remains after an amino acid is deaminated?
Keto acid
156
What is the urea cycle?
pathway by which liver combines ammonia with carbon dioxide to produce less toxic waste
157
What is the Absorptive (fed) state
–About 4 hours during and after a meal
–Nutrients are being absorbed
–Nutrients may be used immediately to meet energy and other needs
158
What is the Postabsorptive (fasting) state?
–Prevails in the late morning, late afternoon, and overnight
–Stomach and intestines are empty
–Body’s energy needs are met from stored fuels
159
How is the Absoprtive state regulated?
by insulin secreted in response to elevated blood glucose and amino acid levels
intestinal hormones gastrin, secretin, cholecystokinin
160
the postabsoptive state is especially critical for the
brain
161
Regulation of the Postabsorptive State
•Regulated mainly by the sympathetic nervous system and glucagon
162
What is the Metabolic rate?
the amount of energy liberated in the body in a given period of time (kcal/hr or kcal/day)
163
how is metabolic rate calculated/measured?
–directly with a calorimeter
–indirectly with a spirometer
164
What is the Basal metabolic rate (BMR)
## Footnote
–A baseline or standard of comparison
–Relaxed, awake, fasting, comfortable room temperature
165
What is Total metabolic rate (TMR)?
the sum of the BMR and energy expenditures for voluntary activities
166
what factors raise TMR?
* Physical activity
* pregnancy
* anxiety
* fever
* eating
* catecholamines and thyroid hormones
167
What factors lower TMR?
* Apathy
* depression
* prolonged starvation
