Lecture 1 (Exam 2)

Question 1

Substrate

Answer 1

Carbs, Fats, and Protein

• fuel sources from which we make energy (ATP)
• moderate to severe muscle effort relies on carbs
• protein provides little energy for cellular activity, but serves as a building block for body’s tissues
• Resting: ~50% carbs, ~50% fats

Question 2

Bioenergetics

Answer 2

• process of converting substrates into energy

- Allows for metabolic reactions to occur

Question 3

Anabolism

Answer 3

-involves the covalent bonding of electrons, protons, and small molecules to produce larger molecules

Question 4

Catabolism

Answer 4

-breakdown of larger molecules and compounds into smaller molecules and compounds

Question 5

Metabolism

Answer 5

• chemical reactions in the body

- catabolism + anabolism = metabolism

Question 6

Anaerobic Metabolism

Answer 6

production of energy (ATP) in the absence of oxygen

-involves cytoplasm (sarcoplasm)

Question 7

Aerobic Metabolism

Answer 7

process occurring in the mitochondria that uses oxygen to produce energy (ATP)
-aka cellular respiration

Question 8

Adenosine Triphosphate (ATP)

Answer 8

• high-energy intermediate compound for for storing and conserving energy
• has all the potential energy to power all of the cell’s energy requiring processes
• cells extract energy from food and store it as ATP

Question 9

Glycolysis

Answer 9

• breakdown of glucose through a pathway that involves a sequence of glycolytic enzymes
• allows carbs to be readily available and easily metabolized by muscles

Question 10

Glycogenesis

Answer 10

the break down of glycogen by the muscles and liver into glucose-1-phosphate

Question 11

Glycogenolysis

Answer 11

the conversion of glycogen into glucose

Question 12

Glycogen

Answer 12

• stored in the sarcoplasm of muscles cells until those cells use it to form ATP
• can be stored in the liver and can be converted back to glucose as needed and then transported by the blood to active tissues where it is metabolized
• aka complex polysaccharide

Question 13

Glucose

Answer 13

6-carbon sugar that is the primary form of carbohydrate used for metabolism

Question 14

Lipolysis

Answer 14

• the process of breaking down triglycerides to its basic units (glycerol and FFA’s) to be used for energy
• controlled by enzymes called lipases

Question 15

Lipogenesis

Answer 15

• the process of converting protein into fatty acids

- FFA’s convert protein into fats in times of starvation

Question 16

Gluconeogenesis

Answer 16

the conversion of protein or fat into glucose

Question 17

Rate Limiting Enzymes

Answer 17

• enzyme found early in a metabolic pathway that determines the rate of the pathway
• activity is determined by the accumulation of substances farther down the pathway that decrease enzyme activity through negative feedback

Question 18

Mass Action Effect

Answer 18

substrate availability influences metabolic rate

• more available substrate = higher pathway activity
• excess of given substrate = cells rely on that energy substrate more than others

Question 19

Endergonic Reactions

Answer 19

• require energy to be added

- endothermic (if heat is gained)

Question 20

Exergonic Reactions

Answer 20

• release energy

- exothermic (if heat is released)

Question 21

Coupled Reactions

Answer 21

release of energy in an exergonic reaction drives an endergonic reaction (exergonic and endergoinc are coupled reactions)
-ex. You eat a cracker (primarily with CHO energy). The body will release the energy gained from the consumed cracker and cause an exergonic reaction (release of energy) which will drive endergonic reactions

Question 22

Laws of Thermodynamics (2)

Answer 22

1) Conservation of energy: energy can neither be created nor destroyed
2) Directionality: the direction of a reaction occurs in the direction of increased entropy (randomness and disorder) and release of free energy

Question 23

How do the Laws of Thermodynamics relate to metabolism?

Answer 23

reactions in the body occur in the direction of energy release, thus, metabolism depends on the direction of reaction

Question 24

What substrates are utilized during rest?

Answer 24

50% carbs and 50% fat

Question 25

Energy Value for Fats

Answer 25

9.4 kcal/g; +70,000 kcal stored in body

Question 26

Energy Value for Protein

Answer 26

4.1 kcal/g

Question 27

Energy Value for Carbs

Answer 27

4.1 kcal/g; ~2,500 kcal stored in body

Question 28

Monosaccharides

Answer 28

• any of the class of sugars (e.g., glucose and fructose) that cannot be hydrolyzed (broken down) to make a simpler sugar
• transported through blood to all body tissue

Question 29

Disaccharides

Answer 29

any of a class of sugars whose molecules contain two monosaccharide residues (e.g. sucrose, lactose, maltose)

• provide energy to muscles
• fuel the central nervous system
• metabolize fat
• keep tissues from consuming protein for energy.

Question 30

Polysaccharides

Answer 30

a carbohydrate (e.g., glycogen) whose molecules consist of a multiple sugar molecules bonded together
-stored in muscles and liver until ready to be used to form ATP

Question 31

How is the rate of energy production controlled by mass action effect?

Answer 31

aka: the availability of of primary substrates
-Substrate availability affects metabolic rate
More available substrates = higher pathway activity
Excess of given substrate (fuel; e.g. carbs) causes cells to rely on that energy substrate more than others

Question 32

How is the rate of energy production controlled by enzyme activity?

Answer 32

Enzymes speed up the breakdown (catabolism) of chemical compounds

• each step of biochemical pathway requires specific enzyme(s)
• More enzyme activity (temperature & pH) = more product