A&P Chapter 25 Study Guide

Define metabolism

the sum of all catabolic and anabolic reaction in the body

What is the difference between catabolic and anabolic reactions?

Catabolism (catabolic reactions) breaks down larger molecules into smaller ones. Anabolism (anabolic reactions) – synthesizes larger molecules from smaller 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?

2

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

This reaction sequence is anaerobic (without oxygen) and provides the cell a net gain of 2 molecule of ATP for each glucose molecule converted to 2 pyruvate molecules.

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

2

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

2

Where does the NADH produced during glycolysis get transported to?

Mitochondria

NAD+ gains an electron to become NADH, so NADH is the (oxidized or reduced?) form of NAD+.

reduced

FADH2 loses an electron to become FADH, so FADH is the (oxidized or reduced?) form of FADH2.

oxidized

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

If oxygen is not available, pyruvate is reduced to form lactate and N A D H is oxidized to NAD

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

Mitochondria

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

2 NET ATP, 2 NADH, and 2 pyruvates.

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?

2 ATP

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

Substrate level phosphorylation is an enzyme uses energy released by a chemical reaction to transfer a phosphate group to a suitable acceptor molecule. Oxidative phosphorylation is an generation of ATP through transfer of electrons from NADH and FADH2 to oxygen by a sequence of electron carriers within the inner mitochondrial membrane

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 (E T C)

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

Oxidative phosphorylation

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 molecules of ATP

Define gluconeogenesis

synthesis of glucose from noncarbohydrate molecules (3-carbon molecules other than pyruvate)

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

is stored in the liver and skeletal muscle

What is the difference between glycogenesis and glycogenolysis?

Glycogenesis converts glucose to glycogen for storage.

Glycogenolysis is the. 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 triglyceride are catabolized into their component parts, enzymes in the cytosol convert glycerol into what molecule?

Pyruvate

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

Beta-oxidation

What molecule is produced from the catabolism of fatty acids in the mitochondria?

acetyl-CoA

How many ATP molecules are produced from the catabolism of one 18-carbon fatty acid molecule?

120 ATP

Define lipogenesis.

the synthesis of lipids

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

Because they must be included in the diet and are also needed to synthesize prostaglandins and some of the phospholipids in plasma membranes throughout 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"?

Low-density lipoproteins (LDLs)

Which group of lipoproteins is considered "good cholesterol"?

High-density lipoproteins (HDLs)

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

Transamination and Deamination

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

1. Proteins are more difficult to break apart than complex carbohydrates or lipids 2. One by-product, ammonium ions, is toxic to cells 3. Proteins form the most important structural and functional components of cells. Therefore, extensive protein catabolism threatens homeostasis at the cellular and system level

What occurs during the absorptive state?

Period following a meal when nutrient is being absorbed and used for growth, maintenance and to replenish energy reserves. Lasts about four hours

What occurs during the postabsorptive state?

The body relies on internal energy reserves. Metabolic reactions are focused on maintaining normal blood glucose levels.

Most cells break down lipids or amino acids, preserving glucose for use by the nervous tissue

What is a ketone body?

organic compound produced by fatty acid metabolism that dissociates in solution, releasing a H+

If these molecules (ketone bodies) release hydrogen ions, how does this affect the pH of the blood?

Lowers blood pH if they release hydrogen ions

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

May cause coma, cardiac arrhythmias, and death

List the 5 main food groups

Fruits, Vegetables, Grains, Proteins, and Dairy

What is the difference between a complete and incomplete protein?

Complete proteins are foods that provide all essential amino acids in sufficient quantities. Incomplete proteins are 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 play major roles in many important physiological processes, such as excitability of cells, maintenance of the skeleton, muscle contraction, hormone production, release of neurotransmitters, blood clotting, buffering, etc. 3. Ions are essential cofactors in many enzymatic reactions

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

Fat-soluble vitamins: Absorbed primarily from the digestive tract along with lipids micelles. Water-soluble vitamins are rapidly exchanged between the fluid compartments of the digestive tract and the circulating blood. Excesses are readily excreted in urine, so hypervitaminosis is relatively uncommon in water-soluble vitamins

Define basal metabolic rate.

rate at which the body expends energy while at rest to maintain vital functions

Define obesity.

body weight more than 20% above ideal weight for a given individual

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

· Radiation – how objects warmer than environment lose heat

· Convection – heat loss to air that moves across the surface of the body

· Conduction – direct transfer of energy through physical contact

· Evaporation – heat loss when water changes from liquid to vapor

o Cools the surface where evaporation occurs

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

Shivering thermogenesis Increased muscle tone increases the energy consumption of skeletal muscle and produces heat

Nonshivering thermogenesis Involves the release of hormones that increase the metabolic activity of all tissues The heat-gain center stimulates the adrenal medullae to release of epinephrine, which increases the rates of glycogenolysis and metabolism

What is brown fat?

adipose tissue rich in heme - containing mitochondria. Important for thermoregulation in infants

What makes brown fat brown?

multiple small lipid droplets and numerous heme-containing mitochondria.