ch 26 nutrition Flashcards
What is nutrition?
–The source of fuel that provides energy for all biological work
–The source of raw materials for replacement of worn-out biomolecules and cells
what is metabolism?
Sum of anabolism and catabolism
Gain weight if
–if intake exceeds output
–Lose weight
if output exceeds intake
Determining factor in weight
Bodies energy balance
If energy intake and output are equal, body weight is stable
What percentage of body wieght is hereditary?
30-50%
Two types of appetite regulators
Short -term and Long-term
Name the short term regulators
- ghrelin
- Peptide YY
- cholecystokinin (CKK)
Properties of ghrelin
- Secreted from parietal cells in fundus of empty stomach
- Produces sensation of hunger
- Ghrelin secretion ceases within an hour of eating
Peptide YY (PYY)
What is the effect of Cholecystokinin (CCK) on digestive system
acts as a signal to stop eating
Main function of short term regulators
–Mechanisms work over periods of minutes to hours
–Makes one feel hungry and begin eating
–Makes one feel satiated and end a meal
Main function of long term appetite regulators
govern caloric intake and energy expenditure over periods of weeks to years
Name the Long term appetite regulators
Leptin
Insulin
Role of Leptin
Informs brain on how much body fat we have
Role of insulin in appetite
- Stimulates glucose and amino acid uptake
- Promotes glycogen and fat synthesis
Which are the two neural networks involved in hunger?
Neuropeptide Y group
Melanocortin group
What is the umbrella term for the chemical signals from the gastrointestinal tract to the brain
Gut-brain peptides
What is the function of neuropeptide Y
Potent appetite stimulant
What is the function of melanocortin
inhibits eating
Which appetite regulators stimulate neuropeptide Y?
Ghrelin
Which appetite regulators inhibit neuropeptide Y?
Insulin
PYY
Leptin
Which appetite regulator stimulates melanocortin?
Leptin
What nuvleus of the hypothalamys has receptors for all 5 chemical signals?
Arcuate nucleus
What effect does gastric peristalsis have on hunger?
It stimulates hunger
Appetite is breifly satisfied by which physical signals
- Chewing and swallowing
- Stomach filling
Which type of food does the neurotransmitter epinephrine stimulate desire for?
–carbohydrates
Which type of food does the neurotransmitter Galanin stimulate desire for?
Fats
Which type of food does the neurotransmitter endorphons stimulate desire for?
Proteins
What is defined as obese?
weight more than 20% above recommended norm for one’s age, sex, and height
What is the optimal range for BMI?
20-25
What is the formula for BMI?
–BMI = W/H2 (W = weight in kg; H = height in meters)
Effects of obesity
increased risk of
- atherosclerosis
- hypertension
- diabetes mellitus
- joint pain,
- kidney stones
- gallstones
- cancer of uterus, breast, and prostate
- sleep apnea
How many calories is a kilocalorie?
1000
How many kcal do Carbs and proteins yield?
4 kcal
How many kcal do fats yield?
9kcal/g
What type of calories are sugar and alcohol?
‘empty’
What is One calorie?
amount of heat required to raise temperature of 1 g of water 1°C
What is a nutrient?
any ingested chemical used for growth, repair, or maintenance of the body
What are the six classes of nutrients?
- Water
- Carbohydrates
- Lipids
- Proteins
- Vitamins
- Minerals
What are macronutrients?
nutrients that must be consumed in relatively large quantities
Which are the macronutrients?
Water, Carbohydrates, Lipids, proteins
What are Micronutrients?
Which are the micronutrients?
Vitamins and minerals
What are Essential nutrients?
Nutrients that cannot be synthesized in body
How many grams of carbohydrates does a well nourished adult body have?
440g
How do sugars function in the body?
As structural components of molecules in the body
As fuel
What is hypoglycemia?
Deficiency of blood glucose
What is the Blood glucose concentration?
A carefully regulated interplay of insulin and glucagon
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
What are the three principle forms of dietary carbohydrates?
Monosaccharides
Disaccharides
Polysaccharides
Name the monosaccharides
–glucose, galactose, fructose
Name the Disaccharides
sucrose (table sugar), maltose, lactose
Name the Polysaccharides (complex carbohydrates)
starch, glycogen, and cellulose
What is the Glycemic index (GI)
effect of a dietary carbohydrate on blood glucose level
What is the effect of high-GI carbohydrates?
stimulate a high insulin demand and raise the risk of obesity and type 2 diabetes mellitus
What are the two types of fiber?
Water soluble fiber
Water in-soluble fiber
Name the dietary fibers
Cellulose, pectin, gums, and lignins
•Well-nourished adult meets what percentage of resting energy needs from fat
80%-90%
Which are the fat soluble vitamins?
A,D,E,K
What are the other functions of lipids?
–Structural
–Chemical precursors
–Important protective and insulating functions
Which fats have structural functions?
Phospholipids and cholesterol
Which fats are chemical precursors?
- Cholesterol
- Thromboplastin
- Fatty acids
Main sources of dietary fats
Saturated fats
unsaturated fats
cholesterol
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
What is the function of Lipoprotein complexes?
transport lipids in plasma
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):
Where does HDL production begin?
In the liver
Name lipoprotein A

chylomicron
Name lipoprotein B

Very low–density lipoprotein
Name lipoprotein C

Low-density lipoprotein (LDL)
Name lipoprotein D

High-density lipoprotein (HDL)
What is the optimum plasma cholesterol concentration?
less than 200mg/L
What is considered pathalogical plasma cholesterol concentration?
240mg/L
Should you have a higher HDL or LDL?
HDL
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
What happens if an excess of protein is consumed?
Can cause kidney damage with nitrogenous waste
How many amino acids are essential (cannot be synthesized in the body)?
8
What are Complete proteins?
high-quality dietary proteins that provide all essential amino acids in the necessary proportions
what are Incomplete proteins?
lower quality proteins that lack one or more essential amino acids
What is Net protein utilization?
the percentage of amino acids in a protein that the human body uses
Is it considered to be healthier to eat more meat or plants?
Plants
Name some sources of complete proteins
Animal proteins of meat, eggs, and dairy products
Which are the incomplete proteins?
plant sources such as beans and rice
What is the chief dietary source of nitrogen?
Protein
What do we mean by Nitrogen balance?
rate of nitrogen ingested equals rate of nitrogen excreted
What is Positive nitrogen balance?
Nitrogen ingestion exceeds its excretion
What is Negative nitrogen balance?
Excretion exceeds ingestion
What are Minerals?
inorganic elements that plants extract from soil or water and introduce into the food web
What are Vitamins?
small dietary organic compounds that are necessary for metabolism
What is the role of minerals and vitamins in nutrition?
Both are essential to our ability to use other nutrients
Minerals constitute what percent of the body mass?
4%
Which mineral is a Key structural component of phospholipids, ATP, cAMP, GTP, and creatine phosphate, and the Basis for the phosphate buffer system
–Phosphorus
Which minerals function as cofactors for enzymes?
–Calcium, iron, magnesium, and manganese
Which mineral is essential for the O2-carrying capacity of Hb and myoglobin
Iron
Which mineral is a component of stomach acid?
chlorine
Which are the best sources of minerals?
vegetables, legumes, milk, eggs, fish, shellfish,
What are precursors to vitamins called?
provitamins
What can an elevated salt intake cause?
Hypertension
Which are the water soluble vitamins?
Vitamins B and C
How are Water-soluble vitamins ingested?
Absorbed with water in small intestine and quickly excreted by kidneys, not stored
How are Fat-soluble vitamins ingested?
Incorporated into lipid micelles in the small intestine and absorbed with dietary lipids
What is the function of vitamin A
- Component of visual pigments
- Promotes proteoglycan synthesis and epithelial maintenance
What is the function of vitamin D
•Promotes calcium absorption and bone mineralization
What is the function of vitamin K
Essential for prothrombin synthesis and blood clotting
What is the function of vitamins A and E
Antioxidants like ascorbic acid
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
What is the function of Vitamin B
- Function as coenzymes
- Assist enzymes
- Make it possible for enzymes to catalyze
What is the world’s most common vitamin deficiency
A
What is the result of a vitamin A deficiency?
•night blindness; dry skin, hair, and conjunctiva; cloudy cornea; and increased incidence of infections
What is Hypervitaminosis
excess of (fat-soluble) vitamin
What is this the formula for?

Glucose catabolism
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
What are the three major pathways of glucose catabolism?
Glycolysis
Anaerobic fermentation
Aerobis respiration
What is Glycolysis?
Glucose (6 C) split into two pyruvic acid molecules (3 C)
What is Anaerobic fermentation?
- Occurs in the absence of O2
- Reduces pyruvic acid to lactic acid
What is Aerobic respiration?
- Occurs in the presence of O2
- Oxidizes pyruvic acid to CO2 and H2O
What are the three stages of cellular respiration?
- Glycolysis
- PYRUVATE OXIDATION and the CITRIC ACID CYCLE
- OXIDATIVE PHOSPHORYLATION
Where and when does glycolysis occur?
in the cytoplasm whether or not there is O2 present
What is the product of glycolysis?
•breaks down glucose into 2 molecules of pyruvate
What are the two phases of glycolysis?
–Energy investment phase
–Energy payoff phase
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
What must happen to peruvate before the citric acid cyle can begin?
pyruvate must be converted to acetyl Coenzyme A (acetyl CoA)
What is another name for the citric acid cycle?
the Krebs cycle
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
What happens during During oxidative phosphorylation?
chemiosmosis couples electron transport to ATP synthesis
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
Fermentation and anaerobic respiration enable cells to produce ATP without the use of..?
Oxygen
What are the two types of fermentation?
Alcohol fermentation
Lactic acid fermentation
What is the flow of energy in cellular respiration?
glucose → NADH → electron transport chain → proton-motive force → ATP
What percentage of the energy in a glucose molecule is transferred to ATP during cellular respiration, making ~32 ATP?
34%
pyruvate is converted to ethanol in which 2 steps?
–The 1st step releases CO2
–The 2nd step produces ethanol
Human muscle cells use what type fermentation to generate ATP when O2 is scarce
lactic acid
Which step does lactic acid fermentation lack that is found in alcohol fermentation?
The release of CO2
What type of fermentation is pictured?

Alcohol Fermentation
what type of fermentation is pictured?

Lactic acid
Cellular respiration produces how many ATP per glucose molecule?
32
fermentation produces how many ATP per glucose molecule
2 ATP
Name one similarity bewteen fermentation and Anaerobi/Aerobic respiration?
They all use glycolysis to oxidize glucose
Name two anabolic synthesis reactions
Glycogenesis
Gluconeogenesis
What is glycogenesis?
The synthesis of glycogen by polymerizing glucose
What is gluconeogenesis
The synthesis of glucose from noncarbohydrates such as glycerol and amino acids
Name two catabolic breakdown reactions
Glycolysis
Glycogenolysis
What is Glycolysis?
the splitting of glucose into two molecules of pyruvic acid in preperation for anaerobic fermentation or aerobic respiration
Why is Glycogenolysis?
The hydrolysis of glycogen to release free glucose or glucose 1 phosphate
Where are Triglycerides are stored?
in body’s adipocytes
What is Lipogenesis?
synthesis of fat from other types of molecules
What is Lipolysis?
breaking down fat for fuel
What does Beta oxidation in the mitochondrial matrix do?
catabolizes the fatty acid components
What are the three methods of amino acid conversion?
- Deamination
- Amination
- Transamination
How does Deamination convert amino acids
removal of an amino group (−NH2)
How does Amination convert amino acids?
addition of −NH2
What is Transamination?
transfer of −NH2 from one molecule to another
what must happen to all amino acids before they can be used as fuel?
Must be deaminated
What remains after an amino acid is deaminated?
Keto acid
What is the urea cycle?
pathway by which liver combines ammonia with carbon dioxide to produce less toxic waste
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
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
How is the Absoprtive state regulated?
by insulin secreted in response to elevated blood glucose and amino acid levels
intestinal hormones gastrin, secretin, cholecystokinin
the postabsoptive state is especially critical for the
brain
Regulation of the Postabsorptive State
•Regulated mainly by the sympathetic nervous system and glucagon
What is the Metabolic rate?
the amount of energy liberated in the body in a given period of time (kcal/hr or kcal/day)
how is metabolic rate calculated/measured?
–directly with a calorimeter
–indirectly with a spirometer
What is the Basal metabolic rate (BMR)
–A baseline or standard of comparison
–Relaxed, awake, fasting, comfortable room temperature
What is Total metabolic rate (TMR)?
the sum of the BMR and energy expenditures for voluntary activities
what factors raise TMR?
- Physical activity
- pregnancy
- anxiety
- fever
- eating
- catecholamines and thyroid hormones
What factors lower TMR?
- Apathy
- depression
- prolonged starvation