Chapter 25 Metabolism, Nutrition, and Energetics Study Guide

Define metabolism

is the sum of all chemical and physical changes that occur in body tissues

What is the difference between catabolic and anabolic reactions

Catabolism converts large molecules into smaller ones, and anabolism converts small molecules into larger ones

When electrons pass from one molecule to another, the electron donor is ______ and the electron acceptor is ________.

_oxidized ; reduced

During glucose metabolism, _______ is an anaerobic process because it does not require oxygen to proceed

glycolysis

What initial organic compound is catabolized during glycolysis? (starting molecule)

glucose

Where does glycolysis take place in the cell?

cytosol

How many net ATP molecules are formed during the glycolysis of one molecule of glucose?

Two

During glycolysis, four ATP are created, but the end product is two net ATP. Why is this so?

2 ATP are used for the initial breakdown of the glucose molecule.

How many pyruvate molecules are produced during glycolysis from one molecule of glucose

two

How many NADH molecules are produced during glycolysis from one molecule of glucose

two

Where does the NADH produced during glycolysis get transported to?

mitocondria

NAD+ gains an electron to become NADH, so NADH is the _______ form of NAD+. FADH2 loses an electron to become FADH, so FADH is the _________ form of FADH2.

reduced ; oxidized

What happens to pyruvate if there are inadequate amounts of oxygen in the cell? (the molecule produced is also known as lactic acid)

pyruvate is reduced to Lactate

In the presence of oxygen, where is pyruvate transported to in the cell?

mitocondria

In the process of glycolysis, what are the end products from the catabolism of one glucose molecule

2 pyruvate + 2 NADH - 2 ATP

Two pyruvate molecules undergo a series of reactions to form two molecules of what molecule during the intermediate step?

acetyl-CoA

How many ATP are produced from the synthesis of acetyl-CoA from pyruvate?

None

What is the difference between substrate-level phosphorylation and oxidative phosphorylation?

Small amount of energy; produces more than 90% of ATP used by body cells

Which step of cellular respiration produces 90-95% of the ATP used by body cells?

Oxidative phosphorylation

Which step of cellular respiration utilizes molecules called cytochromes?

Electron transport chain

The reactions of the electron transport chain produce ATP by which type of phosphorylation

chemiosmotic

The kinetic energy produced by passing hydrogen ions through ATP synthase to generate ATP is called

chemiosmosis

During the process of cellular respiration, how many ATP are formed from one molecule of glucose?

30-32

The production of glucose from noncarbohydrate sources is called

gluconeogenesis

What is glycogen and in what two places is it mainly stored in the body?

Glycogen - glucose molecules stored in the ; liver and skeletal muscles

What is the difference between glycogenesis and glycogenolysis

Glycogenesis - formation of glycogen from excess glucose

Glycogenolysis - breakdown of glycogen to glucose monomers

Which molecule is the most abundant storage form of lipid in the body?

Triglycerides

What are the component parts of one triglyceride molecule?

1 molecule of glycerol and 3 fatty acid molecules.

After the lipolysis of a triglyceride occurs, enzymes in the cytosol convert glycerol into what molecule?

Pyruvate

What process is used to catabolize fatty acids in the mitochondria?

Beta-Oxidation

Fatty acid catabolism in the mitochondria produces _ ________ molecules.

acetyl-CoA

A cell gains 120 ATP from the catabolism of one 18-carbon _ _______ molecule

fatty acid

The synthesis of lipids is called

lipogenesis

Why are linolenic acid and linoleic acid considered essential fatty acids?

Must be consumed and cannot be synthesized in the body

Which group of lipoproteins carry absorbed lipids from the food we eat to the bloodstream?

Chylomicrons

Which group of lipoproteins is considered "bad cholesterol"?

LDL- low-density lipoproteins

Which group of lipoproteins is considered "good cholesterol"?

High-density lipoproteins (HDL's)

What two types of chemical reactions remove amine groups from amino acids during amino acid catabolism?

transamination , deamination

List three factors that make protein catabolism an impractical source of quick energy

-Proteins are more difficult to break apart than are complex carbohydrates or lipids.

-One of the by-products, ammonium ions, is toxic to cells.

-Proteins form the most important structural and functional components of any cell. Extensive protein catabolism threatens homeostasis at both the cellular and system levels

What occurs during the absorptive state? What occurs during the post absorptive state?

In the absorptive state that follows a meal, cells absorb nutrients to be used for growth, maintenance, and energy reserves. Hours later, in the postabsorptive state, metabolic reactions are focused on maintaining the blood glucose level that meets the needs of nervous tissue.

What is a ketone body? If these molecules release hydrogen ions, how does this affect the pH of the blood?

an organic compound produced by fatty acid metabolism that dissociates in solution, releasing a hydrogen ion. ; ketonemia-lowers blood pH

High levels of ketone bodies occur during prolonged starvation. Why is this dangerous?

Ketoacidosis - dangerous acidification of blood by ketone bodies - may cause coma, cardiac arrhythmias, and death

List the 5 main food groups

grains (orange), vegetables (green), fruits (red), dairy products (blue), and protein (purple)

What is the difference between a complete and incomplete protein?

Complete protein - provide all essential amino acids in sufficient quantities.

Incomplete proteins - deficient in one or more essential amino acids.

List three reasons why minerals are important.

1. Ions such as sodium and chloride determine the osmotic concentrations of body fluids.

2. Ions in various combinations play major roles in important physiological processes.

3. Ions are essential cofactors in a variety of enzymatic reactions.

What is the difference between a fat-soluble and water-soluble vitamin?

dissolve in lipids ; rapidly exchanged between fluid in digestive tract and circulating blood, components of coenzymes

Define basal metabolic rate

measurement of the rate at which the body expends energy while at rest to maintain vital functions, such as breathing and keeping warm.

Define obesity

defined as body weight more than 20 percent above the ideal weight for a given individual.

Explain what occurs during the four basic processes of heat exchange called radiation, convection, evaporation, and conduction.

1. Radiation - how objects warmer than environment lose heat.

2. Convection - heat loss to the cooler air that moves across the surface of the body.

3. Evaporation - absorbs energy and cools the surface where it occurs.

4. Conduction - direct transfer of energy through physical contact.

What is the final goal for both shivering- and non-shivering thermogenesis

Shivering: elevate the body temperature/heat generation. Non shivering: release of hormones that increase the metabolic activity of all tissues.

What is brown fat? What makes it brown

A thermogenic tissue containing fat droplets rich in heme, cytochromes, and mitochondria.That make it brown