Chapter 23 - Metabolism, Nutrition, and Energetics

cellular respiration equation

C6 H12 06 + 6O2 ---> 6CO2 + 6H2O + ATP

Where in the cell does the electron transport chain occur?

Inner mitochondrial membrane

During open-heart surgery, which of the following thermoregulatory changes is induced in the patient's body?

Hypothermia

What lipoproteins transport cholesterol to cells of the body?

LDL

NAD, a key coenzyme used in the process of producing ATP, is produced from which water-soluble vitamin?

Niacin

Why are minerals, vitamins, and water classified as essential nutrients?

The body cannot synthesize these nutrients in sufficient quantities.

The production of ATP provides energy to support anabolism as well as other cell functions. Which of the following is NOT supported by energy from ATP?

The diffusion of molecules across the plasma membrane.

Conduction

The direct transfer of heat from one substance to another substance that it is touching.

Metabolism refers to __________.

all of the anabolic and catabolic reactions in the body

The most important factor of good nutrition is obtaining nutrients __________.

in sufficient quantities and qualities

What is a complete protein?

contains all essential amino acids

electron transport chain

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.

Catabolizing fatty acids by beta-oxidation results in the formation of what product?

Acetyl-CoA

Which nutrient in the nutrient pool is most often used to replace structural and functional components of the cell?

Amino acids

Cells in our body are constantly building new molecules to replace worn-out structures. This process is what part of cellular metabolism?

Anabolism

Which lipoprotein carries dietary triglycerides to the liver?

Chylomicrons

citric acid cycle

Completes the breakdown of glucose by oxidizing a derivative of pyruvate to carbon dioxide.

What is the term for the direct transfer of heat energy through physical contact?

Conduction

If the cells are catabolizing amino acids for energy, what is the first step in amino acid catabolism?

Deamination

Which of the following is NOT a way your body generates or conserves heat?

Decreased metabolic rate

What is the term for an amino acid that either cannot be synthesized or is not synthesized in adequate amounts in the body?

Essential amino acid

Why is hypervitaminosis involving water-soluble vitamins relatively uncommon?

Excessive amounts of these vitamins are readily excreted in the urine.

In the nutrient pool, which chemical is best suited for storage of energy content?

Fatty acids

What happens to a glucose molecule as a result of the reactions of glycolysis?

Formation of two molecules of pyruvic acid

Which of the following is an important energy source during periods of starvation, when glucose supplies are limited?

Free fatty acids

Which process in the aerobic metabolism of glucose takes place in the cytosol?

Glycolysis

Which process in the metabolism of glucose does not require oxygen?

Glycolysis

Excess cholesterol leaves somatic cells and is absorbed by __________, which then transport the cholesterol back to the liver.

HDLs

correct statement of glycolysis

There is a net gain of two ATP molecules for each glucose molecule. Submit

citric acid cycle

This process produces some ATP and carbon dioxide in the mitochondrion. Submit

Glycolysis

This process splits glucose in half and produces 2 ATPs for each glucose.

What happens to oxygen when it functions as the final electron acceptor in the electron transport system?

It becomes part of a water molecule.

Why is glucose the primary energy source for cells?

It can be efficiently stored as glycogen, which forms compact, insoluble granules. Submit

electron transport chain

This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration.

Which statement regarding long-term regulation of appetite is true?

Leptin, a peptide hormone released by adipose tissues as they synthesize triglycerides, stimulates the satiety center. Submit

What is the primary focus of nutritional processing in the postabsorptive state?

Maintaining blood glucose levels

What chemical in the catabolism of glucose enters the mitochondria?

Pyruvate

What is the primary role of the citric acid cycle in the production of ATP?

Removal of electrons from substrates

Choose the correct characteristic regarding the short-term mechanism of control of the hypothalamic satiety and feeding centers.

Several hormones of the digestive tract, including CCK, suppress appetite during the absorptive state. Submit

Which is a characteristic of oxidative phosphorylation?

The stepwise passage of electrons by coenzymes embedded in the cristae of the mitochondrion releases energy.

Milk and eggs are complete proteins because they contain __________.

all the essential amino acids in sufficient quantities

The attachment of an amine group in the synthesis of an amino acid is called __________.

amination

The minimum resting energy expenditure of an awake, alert person is the __________.

basal metabolic rate

The process in which fatty acids are broken down into two-carbon fragments is

beta-oxidation

The first step in the sequence of enzymatic reactions in the tricarboxylic acid cycle is the formation of __________.

citric acid

What activity expends the greatest amount of energy per hour?

competitive swimming

The flow and transformation of energy is called __________.

energetics

The mechanism of heat loss that involves the skin and alveoli of the lung is _______.

evaporation

What takes place in the cytosol of a eukaryotic cell?

glycolysis = the breakdown of glucose into two molecules of pyruvic acid, takes place in the cytosol, outside the mitochondria.

orrect sequence of steps as energy is extracted from glucose during cellular respiration.

glycolysis → acetyl CoA → citric acid cycle → electron transport chain Submit

The lipoprotein that transports cholesterol to the liver is

high-density lipoprotein

The synthesis of lipids is called __________.

lipogenesis

Lipids circulate through the bloodstream as __________.

lipoproteins and free fatty acids

Formation of Acetyl CoA

metabolic link between glycolysis and aerobic respiration

All the chemical reactions that occur in an organism are called __________.

metabolism

what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain?

mitochondrion

A cell with excess carbohydrates, lipids, and amino acids will break down carbohydrates in order to __________.

obtain energy

In terms of the movement of electrons, the gain of electrons is called reduction, whereas the loss of electrons is called __________.

oxidation

When chyme arrives in the duodenum, cholecystokinin (CCK) release triggers the secretion of which enzyme?

pancreatic alpha-amylase

Although small quantities of lipids are normally stored in the liver, most of the synthesized triglycerides are exported and bound to __________.

proteins

The period following a meal when nutrient absorption is underway i

the absorptive state

An individual's basal metabolic rate ideally represents __________.

the minimum resting energy expenditure of an awake, alert person

HDLs (high density lipoproteins)

"good" cholesterol lipoproteins made by liver that circulate in the blood to collect excess cholesterol from cells lowest lipid-to-protein ratio

Why is it that lipids cannot provide large amounts of adenosine triphosphate (ATP) in a short period of time?

- Lipids are insoluble in water, and it is thus difficult for water-soluble enzymes to reach them. - Most lipids are processed in mitochondria, and mitochondrial activity depends on the availability of oxygen. - Lipid reserves are difficult to mobilize.

The basal metabolic rate (BMR) is __________.

70 cal/hr or 1680 cal/day in the average individual

What is meant by the term balanced diet?

A balanced diet supplies all ingredients to maintain homeostasis.

Catabolism

Metabolic pathways that break down molecules, releasing energy.

Anabolism

Metabolic pathways that construct molecules, requiring energy.

Which part of the cell is most heavily involved in energetics?

Mitochondria

Where in the cell does the citric acid cycle occur?

Mitochondrial matrix

All nutrients can be used by the mitochondria to provide energy. In what form are these nutrients "fed" into the mitochondria?

Two-carbon fragments

Which vitamin is required for the synthesis of visual pigments?

Vitamin A

Hypothermia

abnormally low body temperature

The process that breaks down organic substrates, releasing energy that can be used to synthesize ATP or other high-energy compounds, is __________.

catabolism

In resting skeletal muscles, a significant portion of their metabolic demand is met through the __________.

catabolism of fatty acids

When blood glucose concentrations are elevated, the glucose molecules can be __________.

catabolized for energy, used to build energy reserves, and used for growth and tissue repair

In most tissues, the transport of glucose into the cell is dependent on the presence of a carrier protein that is stimulated by which of the following?

insulin

Before the large vitamin B12 molecule can be absorbed, it must be bound to __________.

intrinsic factor

During the catabolism of glucose, some energy is captured by __________ molecules, while the rest of the energy is lost mainly as ________.

reduced; heat

basal metabolic rate (BMR)

the rate at which the body burns energy when the organism is resting

For each glucose molecule converted to two pyruvates, the anaerobic reaction sequence in glycolysis provides a net gain of __________.

two ATP for the cell