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125 terms

Nutrition Ch. 7

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What is the sum of all chemical reactions that go on in living cells?
metabolism
In photosynthesis, the plant uses energy from the sun, plus water and carbon dioxide, to synthesize _____.
carbs
A typical cell contains "powerhouses," which is another name for what?
mitochondria
what is a feature of catabolic reactions?
they involve the release of energy
What term is specific to reactions in which simple compounds are combined into more complex molecules?
anabolic
where is the site of lipid synthesis in the cell?
smooth endoplasmic reticulum
what is an example of an anabolic reaction?
cholesterol synthesis from acetyl CoA molecules
the formation of glycogen by the liver cell is an example of what?
anabolism
what is an example of a catabolic reaction?
urea formation from an amino acid
Three functions of the liver.
synthesis of urea, synthesis of glycogen, and conversion of fructose to glucose
what is the approximate percent efficiency of conversion of food energy to ATP energy in the body?
50%
In the adult body, food energy not stored as fat or glycogen is lost as ____.
heat
define a coenzyme
an organic molecule required for the functioning of an enzyme
the hydrolysis of ATP that often occurs simultaneously with the synthesis of many compounds is an example of what?
couple reactions
what metabolic reaction occurs when a cell uses energy?
ATP releases a phosphate group and become ADP.
what is the major energy carrier molecule in most cells?
ATP
what are the basic units derived from food?
glycerol, fatty acids, and amino acids
approximately what percentage of the body's energy expenditure is furnished by amino acids?
10-15%
what can be formed by CoA molecules?
cholesterol, stearic acid, and carbon dioxide
glycolysis is the conversion of what?
glucose to pyruvate
what is the series of reactions involving the conversion of glucose to pyruvate known as?
glycolysis
what are some aspects of glycolysis?
it generates ATP, it occurs in the absence of oxygen, and it generates two molecules of pyruvate for each molecule of glucose
what is the sequence of events in the complete oxidation of glucose?
glycolysis -> TCA cycle -> electron transport chain
what cannot be formed from pyruvate in humans?
linoleic acid
what is a feature of aerobic metabolism?
energy is produced more slowly than in anaerobic metabolism
what does an aerobic reaction require?
oxygen
the rapid breakdown of glucose in muscles produces large amounts of pyruvate, which leads to a fall in pH within the muscle and that the muscle responds by converting excess pyruvate to what?
lactate
the Cori cycle involves the interconversion of what two substances?
lactate and glucose
what is the response of the muscles when a person is performing intense physical exercise and begins to feel fatigued?
to synthesize more lactate
what are some fates of metabolized glucose?
acetyl CoA, amino acids, and muscle glycogen
what nutrient can be made from the compounds composed of 2-carbon skeletons?
fatty acids
what is a possible fate of acetyl CoA?
synthesis to fatty acids
what is the first product of fatty acid catabolism?
Acetyl CoA
fatty acid oxidation results in the direct production of what?
acetyl CoA
production of excessive amounts of acetyl CoA molecules lead to the synthesis of ______.
fatty acids
in a triglyceride that contains 54 carbon atoms, how many can become part of glucose?
3
what compounds can be formed from fatty acids?
ketones, acetyl CoA, and carbon dioxide
approximately what percentage of the weight of triglycerides cannot be converted to glucose?
95%
what percentage (by weight) of a triglyceride molecule can be converted to glucose?
5%
how many acetyl CoA molecules may be obtained from oxidation of an 18-carbon fatty acid?
9
what dietary components can be used to synthesize and store glycogen?
lactose, wheat starch, and plant protein
Glucose, Glycerol and Amino acids can be used to make what?
body protein
what is the immediate consequence of a cellular deficiency of oxaloacetate?
the slowing of the TCA cycle
what are some precursors for oxaloacetate synthesis?
starch, glucose, and protein
what is the immediate fate of excess dietary protein in the body?
deaminated
after digestion and absorption, an amino acid not used to build protein will be first subjected to ______.
removal of its amino group
what leads to the production of urea?
oxidation of amino acids
When energy-yielding nutrients are consumed in excess, what can lead to storage of fat?
fat, carbohydrates, and protein
If the carbohydrate content of the diet is insufficient to meet the body's needs for glucose, what can be converted to glucose?
amino acids
When protein consumption is in excess of body needs and energy needs are met, the excess amino acids are metabolized and the energy in the molecules is _______.
stored as glycogen and fat
What are the products from the complete oxidation of fatty acids?
Water, carbon dioxide, and energy
In addition to energy, what are the principal end products of cellular oxidation of carbohydrates?
Water and carbon dioxide
what products are generated via the TCA cycle or electron transport chain?
water, energy, and carbon dioxide
At what point is oxygen used in the electron transport chain?
at the end
Which of the following accounts for the higher energy density of a fatty acid compared with the other energy-yielding nutrients?
a. Fatty acids have a lower percentage of hydrogen-carbon bonds
b. Fatty acids have a greater percentage of hydrogen-carbon bonds
c. Other energy-yielding nutrients have a lower percentage of oxygen-carbon bonds
d. Other energy-yielding nutrients undergo fewer metabolic reactions, thereby lowering the energy yield
b. Fatty acids have a greater percentage of hydrogen-carbon bonds
The number of ATP molecules that can be produced from a molecule of protein, fat, or carbohydrate is generally related to the number of atoms of what?
hydrogen
Approximately how many molecules of ATP are generated from the complete oxidation of one molecule of glucose?
32
What can be synthesized from all three energy-yielding nutrients?
acetyl CoA
what is the most likely explanation for the body's higher metabolic efficiency of converting a molecule of corn oil into stored fat compared with a molecule of sucrose?
There are fewer metabolic reactions for disassembling the corn oil and re-assembling the parts into a triglyceride for uptake by the fat cells
. Approximately how many ATP molecules are synthesized from the complete oxidation of a molecule of palmitic acid?
129
If a person consumes 100 kcalories in excess of energy needs from table sugar, approximately how many of the kcalories are stored in the body?
75
If a person consumes 100 kcalories in excess of energy needs from olive oil, approximately what percentage of the kcalories are stored in the body?
95
what is a characteristic of the metabolism of specific macronutrients?
The rate of fat oxidation does not change when fat is eaten in excess
How does excess carbohydrate intake contribute to obesity?
It spares oxidation of body fat and dietary fat
what is the body's first response to the absorption of abundant amounts of carbohydrate?
Synthesis and storage of glycogen
what are some features of the metabolism of surplus dietary carbohydrate in human beings?
excess glucose suppresses fat oxidation, excess glucose is first used to fill glycogen reserves, and conversion of excess glucose to fat occurs only to a very limited extent.
what is a feature of the metabolism of surplus dietary fat?
excess fat is almost all stored
After the first day or so of fasting, what substance is most depleted in the body?
glycogen
Of the total amount of carbohydrate energy consumed by the body, approximately what percentage is used by the brain and nerve cells?
50%
If a normal person expends 1200 kcalories while at rest, approximately how many are used by the brain?
300
During the first few days of a fast, what energy source provides about 90% of the glucose needed to fuel the body?
protein
what dietary nutrients would most rapidly reverse a state of ketosis in a starving person?
Carbohydrate
How soon would death occur from starvation if the body was unable to shift to a state of ketosis?
within 3 weeks
A feature of ketosis is that it ______.
occurs when fats are partially oxidized.
The effects on metabolism from starvation are similar to those from _____.
fasting
A person said to have acetone breath most likely has the condition known as ______.
ketonemia
what is used to supply some of the fuel needed by the brain only after the body has been fasting for a while?
ketones
Elizabeth has been fasting for 4 days in observance of her religious beliefs. You note that her breath smells "fruity." This is most likely due to what?
her body's shift to a state of ketosis
Ketonemia is defined as an elevation of what?
ketones in the blood.
How are ketones formed?
Condensation of acetyl CoA molecules
what are some general features of starvation in people
a decrease in metabolic rate, a decrease in immune function, and a decrease in body temperature.
what is a characteristic of ketosis?
it may lead to a lowering of blood pH
what is classified as a ketone body?
Acetoacetate
what are some adverse side effects of typical low-carbohydrate diets?
fatigue, nausea, and constipation
Lillie has been losing weight by following a very-low-carbohydrate diet for 2 months. Her primary care physician just diagnosed ketosis through a urine sample. Which of the following symptoms would be another way the physician might have suspected ketosis in Lillie?
Fruity odor on breath
A person with fruity odor on the breath demonstrates evidence of metabolic ________.
ketosis
What type of diet is associated with the development of ketosis?
low carbohydrate
The health benefits of moderate alcohol intake occur in people with a starting age (years) of ____.
35
Binge drinking is defined as the successive consumption of _____.
4-5 drinks
what is a definition of a moderate level of alcohol intake per day for the average-sized woman?
up to 1 drink
what is a definition of a moderate level of alcohol intake per day for the average-sized man?
up to 2 drinks
The chemical structure of ethanol consists of what?
2 carbons and 1 hydroxyl group.
With alcohol beverages, the ratio of proof to alcohol percentage is _____.
2:1
The amount of ethanol in a typical "drink" is what?
0.5 ounces
Approximately how many kcal are contained in 3 ounces of 80-proof rum?
200
One average-sized can of beer contains about the same amount of alcohol as what?
1½ ounces of vodka.
What is the percentage of ethanol in 120-proof scotch whiskey?
60
what is one explanation for the generally lower tolerance for alcohol in women in comparison to men?
Women have lower amounts of stomach alcohol dehydrogenase
What organ is first to absorb alcohol after a person takes a drink?
stomach
What is the primary organ that oxidizes alcohol?
liver
what is best suited for slowing alcohol absorption?
carbohydrate snacks
The metabolism of alcohol begins in the _____.
stomach
what is characteristic of alcohol absorption?
It is slowed when the stomach is full of food
what plays a major role in regulating the elimination of alcohol from the body?
liver alcohol dehydrogenase
What is acetaldehyde?
An intermediate in alcohol metabolism
what are some characteristics of alcohol metabolism?
There are gender differences in the rate of breakdown, The average person needs about two hours to metabolize two drinks, and The amount of alcohol in the breath is proportional to the amount in the blood
Your middle-aged aunt says that she always feels more "tipsy" than her same-size husband, even though their alcohol intake is the same. You respond by saying to your aunt _____.
"Women have less stomach alcohol dehydrogenase enzyme and consequently absorb more of the alcohol into the bloodstream."
In the average healthy person, about how much time is required by the liver to process the alcohol in a typical drink?
1 hour
Excess alcohol intake leads to a reduction in the synthesis rate of _____.
liver glucose
What is the sequence of stages that brings about advanced liver disease caused by chronic alcohol toxicity?
Fat accumulation, fibrosis, cirrhosis
What is MEOS?
A system of enzymes that oxidizes alcohol and drugs
Approximately what percentage of alcohol in the body is eliminated via the urine and breath?
10
what function is first to be affected when a person begins to drink alcohol?
Judgment and reasoning
What is the minimum blood alcohol percentage that defines legal drunkenness in most states?
0.10
What minimum concentration of blood alcohol leads to impaired judgment and increased heart rate?
0.05
What minimum concentration of alcohol in the blood is usually fatal?
0.5%
what is a consequence of alcohol intake?
Antidiuretic hormone production is suppressed
The Wernicke-Korsakoff syndrome in people with chronic alcohol abuse stems primarily from a deficiency of _____.
thiamin.
what is a feature of ethanol metabolism?
It increases gastric acid output
chronic excess alcohol intake leads to what effects?
the liver releases more folate into the blood, the kidneys excrete more folate via the urine, and the small intestine absorbs less folate from the diet.
Approximately how many kcalories from ethanol are contained in one standard drink of vodka or rum?
100
Approximately what percentage of all traffic fatalities involves alcohol?
40%
What is the median weekly number of alcoholic drinks consumed by college students?
1 1/2
What fraction of all domestic violence incidents involve alcohol use?
2/3
what is a characteristic of alcohol use?
ingestion of alcohol cools the body