Unit 8 Metabolism, nutrition, energetics

Which of the following is true about the citric acid, or Krebs, cycle?

It occurs in the matrix of mitochondria

Amino acids and fatty acids may enter the citric acid cycle by way of:

acetyl-CoA

Where in a cell does glycolysis occur?

cytoplasm

When the blood glucose level becomes low, which of the following would most likely increase?

glycogenolysis

During cellular respiration, which set of reactions produces the most ATP?

electron transport

Which of these is a hormone that causes an increase in blood glucose concentration?

epinephrine

Fatty acids that are necessary for proper health but cannot be synthesized by the body are called

essential fatty acids.

During cellular respiration, how much of the original energy in the glucose molecule is transferred into ATP and how much is instead converted into (lost as) heat?

40% to ATP and 60% to heat.

In the absence of oxygen, what is produced at the end of glycolysis?

lactic acid

Urea is formed in the

liver

Which of the following have the most similar functions?

niacin (NAD) and riboflavin (FAD)

NAD, which acts as a hydrogen carrier in the cell, is derived from:

niacin (nicotinic acid)

Glycolysis breaks down glucose into

pyruvic acid

The function of the citric acid cycle is to

remove hydrogen atoms from organic molecules and transfer them to coenzymes.

The increase in body temperature during exercise:

results from a greatly increased metabolism

Most nutrient absorption takes place in the

small intestine

The carbon dioxide of respiration is formed during

the citric acid cycle.

A person decides to go on a hunger strike to further one of his favorite causes. After many days with nothing but water you would expect to observe

All of the answers are correct. a) elevated levels of glucocorticoids. b) ketone bodies in his urine. c) lowered blood pH.

ATP can be used for

All of the answers are correct. muscle contraction. ion transport. protein synthesis. glycogen synthesis.

The molecule that supplies our cells with an immediate source of energy is:

ATP

________ is deficient in one or more of the essential amino acids.

An incomplete protein

Which of the following is calculated directly by using a person's height and weight?

BMI

Acetyl CoA for the citric acid cycle may be formed through metabolism of:

All of the above fatty acids glucose amino acids

Glycolytic breakdown of glucose first results in ________ molecules.

All of the answers are correct 2 pyruvate (pyruvic acid) 2 NADH 2 ATP (net)

Glucocorticoids have which of the following effects on general peripheral tissues?

All of the answers are correct. a) They increase the conversion of amino acids to pyruvate. b) They increase gluconeogenesis. c) They increase glycogenolysis.

Lipogenesis generally begins with

acetyl-CoA.

Where in the cell does electron transport occur?

cristae of mitochondria

Deficiency in what vitamin can result in a condition called scurvy?

cytochromes

Linoleic acid and linolenic acid are examples of

essential fatty acids.

The vitamin that is a coenzyme in amino acid and nucleic acid metabolism is

folic acid (folate)

A mature red blood cell has no mitochondria. Because of this, it can only make ATP by:

glycolysis

In the absence of oxygen, which is the last process that can occur to make ATP?

glycolysis

A high uric acid level (above 7.4 mg/dl) can lead to the painful condition known as

gout

A decrease in body weight occurs when caloric intake:

is less than basal metabolism plus external work

Body temperature:

is regulated primarily by regulating heat loss

Epinephrine

is released from the adrenal medulla and acts to stimulate glycogenolysis

Which of the following describes the role of NADH during cellular respiration?

it carries hydrogen to the site of electron transport reactions

A person with untreated diabetes mellitus would be in a prolonged:

postabsorptive state

In transamination, the amino group of an amino acid is ________, yielding a different amino acid.

transferred to another molecule

Low-density lipoproteins function to:

transport cholesterol to cells for use in plasma membranes or hormone synthesis

True or False: One of the major results of cellular respiration is heat.

true

The conversion of ammonia into a less toxic substance produces

urea

Pellagra, an epithelial and mucosal deterioration, results from a deficiency in

vitamin B3 (niacin).

In a healthy individual who has just finished eating a large nutrient-balanced meal:

blood plasma will have an increased concentration of fats, glucose, and amino acids

The process(es) that occur(s) in the mitochondria is/are:

both b and c Krebs cycle electron transport

Impaired fat absorption in the intestine would interfere with the absorption of

vitamin A

An increased caloric intake without an increase in external expenditure would most likely lead to:

weight gain

The metabolic rate of an individual may be lower than the BMR

while sleeping

The citric acid cycle

begins with the formation of a molecule of citric acid.

Which of the following is the first step in ATP production from fat?

beta-oxidation

The process that catabolizes fatty acids to acetyl-CoA is called

beta-oxidation.

Cellular respiration is best described as the:

breakdown of glucose into CO2 and H2O and production of ATP.

Where does the breakdown of glucose to pyruvic acid occur?

cytoplasm

When the body is relying on internal energy reserves to continue meeting its energy demands, it is in the ________ state.

postabsorptive

The process by which electrons are transferred from NAD through various cytochromes and finally to oxygen occurs to:

provide energy for ATP formation.

Reactions within ________ provide most of the energy needed by a typical cell.

the mitochondria

Homeostatic control of body temperature is termed

thermoregulation

Basal metabolism most directly refers to the energy output required:

to maintain basic body functions

The vitamin that plays a role in maintaining epithelia and is required for the synthesis of visual pigments is vitamin

A

The food pyramid recommends many servings a day of dark-green and orange vegetables. Which vitamin is particularly abundant in this food group?

All of the answers are correct A C E folic acid

A balanced diet should

All of the answers are correct include adequate substrates for the production of energy. provide essential amino acids and fatty acids. contain adequate amounts of vitamins and minerals.

All of the following take place during the absorptive state except

ketone bodies begin to form

The hormone ________, which suppresses appetite and stimulates satiety, is released by adipose tissue.

leptin

All of the following occur during the postabsorptive state except that

levels of blood glucose are elevated

The nutrients that yield the most energy per gram when metabolized are

lipids

All of the following are true of beta-oxidation except that

lipids are converted into glycogen molecules.

During starvation (a long-term situation):

little or no glycogen is stored in the liver

The sum of all of the biochemical processes going on within the human body at any given time is called

metabolism

________ contains all of the essential amino acids.

A complete protein

All cells use which of the following directly for energy to fuel their work?

ATP

Inadequate exposure to sunlight can result in decreased amounts of vitamin ________ in the body.

D

The vitamin that is required for proper bone growth and for calcium absorption and retention is vitamin

D

The vitamin that prevents breakdown of vitamin A and fatty acids is vitamin

E

Which of the following statements is true about carbohydrates?

Their main use is to provide energy.

True or False: When ATP breaks down, the products can then be used to synthesize more ATP.

True

Which of the following carry excess cholesterol from peripheral tissues to the liver?

Which of the following carry excess cholesterol from peripheral tissues to the liver?

About 60% of the heat loss from a nude person standing in a room at 70 degrees (F) is by radiation. Heat loss in this manner is based on the principal that:

body temperature is greater than the surrounding temperature, so the nude person releases more heat than he receives

The following equation represents: C6H12O6 + 6 O2 --------> 6 CO2 + 6 H2O + ATP + heat

cellular respiration.

The largest lipoproteins, ________, are produced by intestinal epithelial cells from the fats in food

chylomicrons

Decreasing blood glucose is a stimulus for the secretion of:

glucagon

Which of the following hormones is most directly involved during the post-absorptive state?

glucagon

Which of the following hormones increase the blood glucose level?

glucagon and epinephrine

The conversion of glycerol and amino acids into glucose in called:

gluconeogenesis

During lipolysis,

triglycerides are broken down into glycerol and fatty acids.

A deficiency in vitamin D would result in which of the following disorders?

rickets

The process of synthesizing glucose from noncarbohydrates is called

gluconeogenesis

When a cell needs energy, glycogen may be hydrolyzed to:

many glucose molecules.

Resting energy expenditure is most directly determined by monitoring

respiration

Which part of glucose metabolism yields the greater amount of ATP?

electron transport system

During electron transport, the transfer of electrons through the cytochromes to oxygen:

makes more ATP than can be made directly from glycolysis.

The lipoproteins that carry absorbed lipids from the intestinal tract to the bloodstream are the

chylomicrons.

During cellular respiration, which set of reactions releases carbon dioxide?

citric acid (Krebs) cycle

It's been 5 hours since you had breakfast and now you're thinking about trying the new Mexican lunch place that just opened up across the street. The more you think about it, the hungrier you get. That's the result of the ________ that your empty stomach is releasing into your bloodstream.

ghrelin

Although other nutrients can feed into the citric acid cycle, ________ yields energy the quickest.

glucose

During the absorptive phase of metabolism

glucose is the primary energy source for most cells

All of the following are reasons why glucose is the primary energy source for cells except

glycogen breakdown occurs very slowly.

There are ________ essential amino acids that the body either cannot synthesize or that cannot be produced in amounts sufficient for growing children.

10

What is the net energy yield of the citric acid (Krebs) cycle?

2 ATP

Obesity is defined as a body weight more than ________ percent above the ideal body weight for an individual.

20

Cells synthesize new organic components for which of the following reasons?

All of the answers are correct. structural maintenance growth and repair production of secretions

The electron transport system

All of the answers are correct. receives electrons from coenzymes. produces more the ATP than Glycolysis is located on the inner mitochondrial membrane (the cristae).

An adult weighing 130 lb. requires the same amount of energy to walk up a flight of stairs as does an adult weighing 280 lb.

False. It requires more energy for the larger adult because he/she has a higher BMI.

The "good" type of lipoprotein that carries cholesterol from tissues to liver is:

HDL (high-density lipoproteins)

Which of the following increases the breakdown of triglycerides in adipose tissue?

all of the above epinephrine thyroid hormone exercise

Amino acids can be converted into:

all of the above fatty acids other amino acids. glucose.

In the metabolism of proteins, amino acids may be converted to:

all of the above nitrogen containing derivatives such as hormones structural proteins new enzymes carbohydrates and fats

The minimum resting energy expenditure of an awake, alert person is called

basal metabolic rate

Which of the following is most likely to occur if blood glucose levels are elevated?

glycogenesis

Blood glucose levels are increased by:

glycogenolysis

The caloric requirements of an athlete training for a marathon would most likely be:

greater than the recommended 2000 kcal/day diet for an average adult

In which of the following conditions does the hypothalamus fail to function?

heat stroke

A disorder caused by the ingestion of excessive quantities of a fat-soluble vitamin is known as

hypervitaminosis

At the Holy Frijoles restaurant, you order a burrito grande with extra sour cream and cheese and an order of tortilla chips with guacamole. You're very satisfied with your meal—it's a lot of food—and as you finish off the last of the chips, the satiety center in your ________ starts letting you know that you've had enough to eat now

hypothalamus

The area of the brain that regulates body temperature is the

hypothalamus

A political prisoner has been on a hunger strike for seven days. Compared to normal, he has:

increased release of fatty acids from adipose tissue

Temperature regulation is:

influenced by peripheral thermoreceptors in the skin