Unit 4: Bioenergetics

Question 1

What is the first law of thermodynamics?

Answer 1

Energy cannot be created or destroyed.

Question 2

What is the second law of thermodynamics?

Answer 2

Entropy increases.

Question 3

What is the link between this course and the first law of thermodynamics?

Answer 3

Glucose (“energy”) ———> ATP (“energy”)

Question 4

What is the link between this course and the second law of thermodynamics?

Answer 4

• converting food potential energy to ATP potential energy

- cell/organisms also tend toward entropy therefore, require energy to maintain order (life, homeostasis)

Question 5

What is an oxidation? What part do we focus on in this course?

Answer 5

The loss of electrons from molecules, atoms or ions by adding oxygen or removing hydrogen. Releases energy. We focus on the removal of H.

Question 6

What is a reduction? What part do we focus on in this course?

Answer 6

Increase in the number of electrons in molecules, often by adding hydrogen or by removing oxygen require input of energy. We focus on the addition of H.

Question 7

True or false: Foods with a high ratio of hydrogen to oxygen are more likely to lose electrons, therefore oxidize and release more energy.

Answer 7

True. Examples are steric acid (a fat) with a H:O ratio 18:1. Glucose has a H:O ratio 2:1.

Question 8

What is ATP composed of?

Answer 8

• 3 phosphate groups
• ribose
• adenine

Question 9

What is the equation of ATP hydrolysis, which releases energy?

Answer 9

ATP + H2O ———> ADP + Pi + energy

Question 10

What are 2 important points involving ATP and phosphate?

Answer 10

• usually donates/transfers Pi to acceptor

- very good donor of phosphate

Question 11

What are the types of work done by ATP in animal cells? What are the products of these reactions?

Answer 11

-biosynthesis
-active transport
-movement
Products of these reactions are ADP and Pi.

Question 12

What other reaction is paired with the work done by ATP in animal cells?

Answer 12

Cellular respiration

Question 13

What is the purpose of enzymes?

Answer 13

Increase the rate of chemical reactions without being consumed.

Question 14

True or false: Enzymes increase activation energy.

Answer 14

False. They lower activation energy by forming enzyme-substrate complex.

Question 15

True or false: One enzyme can work in many different reactions.

Answer 15

False. Enzymes are very specific.

Question 16

What are some cofactors required by enzymes?

Answer 16

Vitamins and minerals

Question 17

True or false: Enzymes work in all conditions.

Answer 17

False. Most enzymes work best under narrowly defined conditions such as temperature, pH and the concentration of substrates and products.

Question 18

How are enzymes organized in metabolic pathways?

Answer 18

Into multiple reactions. Reactions catabolized by enzymes are more efficient (capture more energy) then in one large reaction.

Question 19

What does the NAD+/NADH hydrogen shuttle do?

Answer 19

• breaks C-H bonds in organic food

- transfers H from carbon (food) to oxygen - makes water.

Question 20

What does the FAD/FADH2 hydrogen shuttle do?

Answer 20

-transfers hydrogen from organic molecule to oxygen

Question 21

What does the NADP+/NADPH hydrogen shuttle do?

Answer 21

Transfers hydrogen from water to carbon to make organic molecules. This is hydrogen shuttle works in the opposite direction as NAD+/NADH shuttle.

Question 22

True or false: Hydrogen transfers are not direct. Many intermediate steps are required.

Answer 22

True.