Chapter 25 - Metabolism SG

Define metabolism. 

The same of all chemical and physical changes that occur in body tissues.

What is the difference between catabolic and anabolic reactions? 

Catabolic reactions: Convert large molecules into smaller ones

Anabolic reactions: Convert small molecules into larger ones

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

Electron Donor: Oxidized

Electron Acceptor: 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? 

4 Total, 2 Net.

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

Because two are consumed in the first half of Glycolysis.

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

2 pyruvate molecules

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

Two NADH

Where does the NADH produced during glycolysis get transported to? 

It can get transported into ETC or stay in the cytosol to reduce Pyruvate to Lactate in anaerobic conditions.

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

NADH = Reduced Form
FADH = Oxidized Form

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

It becomes Lactate

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

To the Citric Acid Cycle (mitochondrial matrix)

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

2 Pyruvate, 2 NADH, 2 ATP (Net).

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? 

Substrate-level phosphorylation: an enzyme uses energy released by a chemical reaction to transfer a phosphate group to a suitable acceptor molecule.

Oxidative phosphorylation: Generation of AT P through transfer of electrons from NADH and to oxygen by a sequence of electron carriers within the inner mitochondrial membrane and water is formed.

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? 

ETC

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 (chemiosmotic phosphorylation)

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

30 to 32 molecules of ATP

Define gluconeogenesis.  

Synthesis of glucose from noncarbohydrate molecules

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

Glucose molecules are stored as glycogen.

It’s a energy reserve that can be broken down when there isn’t enough glucose.

They are stored in the liver and skeletal muscles

What is the difference between glycogenesis and glycogenolysis? 

Glycogenesis: converting glucose to glycogen for storage

Glycogenolysis: Breaking down 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 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? (Use the information in Figure 25-7 Lipolysis and Beta-oxidation step 4 to answer this question) 

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 cannot be synthesized in the body and must be obtained from the diet.

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.

Which group of lipoproteins is considered “good cholesterol”? 

High-density lipoproteins

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

Transaminations and deaminations

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

1) Proteins are more difficult to break apart
2) It releases a toxic by-product (ammonium ions)

3) Extensive protein break down threatens homeostasis at both the cellular and system levels.

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

Absorptive: This is the period following a meal when nutrients are being absorb and used for growth, maintenance and to replenish energy reserves. This lasts about four hours.

Postabsorptive: This is hours later when metabolic reactions are focused on maintaining the blood glucose levels. Most cells break down lipids or amino acids, preserving glucose for use by the nervous tissue.

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

Ketone body = An organic compound produced by fatty acid metabolism that dissociates in solution, releasing H+. This lowers pH of blood.

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

This can lead to ketosis (high concentration of ketone bodies in body fluids). This can then lead to ketonemia (presence of ketone bodies in the bloodstream). This lowers blood pH and ketoacidosis (dangerous acidification of blood by ketone bodies) which can lead to 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 = Foods that provide all essential amino acids in sufficient quantities (beef, fish, poultry, eggs, and milk)

Incomplete = Deficient in one or more essential amino acids (usually plant proteins).

List three reasons why minerals are important. 

1) Ions like Na and Cl determine the osmotic concentrations of body fluids

2) Ion play a role in physiological processes (excitability of cells, maintenance of the skeleton, muscles contraction, hormone production, neurotransmitter released, blood clotting, buffering, etc)

3) Ions are essential co-factors in many enzymatic reactions

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

Fat-soluble = Absorbed primarily from the digestive tract along with lipid micelles (dissolve in lipids).

Water-soluble = Components of enzymes and rapidly exchanged between the fluid compartments of the digestive tract and circulating in the blood.

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 (cools the surface where it occurs)

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

To generate heat/promote heat gain to prevent hypothermia

What is brown fat? What makes it brown? 

Adipose tissue rich in heme - containing mitochondria.

Thermogenic tissue with fat cells characterized by multiple small lipid droplets and heme (which makes it brown).