How Cells Harvest Energy (Chapter 7)

Question 1

Plants, Algae, and some bacteria harvest energy of sunlight through photosynthesis, converting radiant energy into what?

Answer 1

Chemical Energy

Question 2

An organism able to build all the complex organic molecules that it requires as its own food source, using only simple inorganic compounds

Answer 2

Autotroph

Question 3

This type of organism is known as a “Self-feeder.”

Answer 3

Autotroph

Question 4

An organism that cannot derive energy from photosynthesis or inorganic chemicals, and so must feed on other plants and animals, obtaining chemical energy by degrading their organic molecules.

Answer 4

Heterotroph

Question 5

1. This type of organism is “fed by others”

Answer 5

heterotroph

Question 6

At least 95% of the kinds of organisms on Earth—all animals and fungi, and most protists and prokaryotes—are known as autotrophs or heterotrophs?

Answer 6

Heterotrophs

Question 7

• This organism extracts energy from organic compounds
• It has the additional capacity to use the energy from sunlight to synthesize organic compounds.

Answer 7

Autotroph

Question 8

All organiisms use cellular respiration to extract energy from inorganic or organic molecules?

Answer 8

organic molecules

Question 9

The process by which energy is harvested

Answer 9

Cellular respiration

Question 10

The oxidation of organic compounds to extract energy from chemical bonds

Answer 10

cellular respiration

Question 11

Define cellular respiration

Answer 11

The metabolic harvesting of energy by oxidation, ultimately dependent on molecular oxygen; carried out by the Krebs cycle and oxidative phosphorylation.

Question 12

• This process is responsible for harvesting energy by oxidation.
• It is dependent on molecular energy
• Carried out by the Krebs Cycle and Oxidative Phosphorylation

Answer 12

Cellular Respiration

Question 13

What 2 bond types are in abundance in carbohydrates?

Answer 13

1. Carbon–hydrogen (C—H) bonds
2. Carbon–oxygen (C—O) bonds.

Question 14

Extracting energy from the complex organic mixture in most foods is tackled in stages.

Describe the stages of [Energy Metabolism]

Answer 14

1. First, enzymes break down the large molecules into smalller ones, this process is called digestion.
2. Then, other enzymes dimantle these fragments a bit at a time, harvesting energy from C-H bonds and other chemical bonds

• The reactions that break down these molecules are oxidations
• (therefor, Energy metabolism is concerned with redox reactions)

Question 15

Energy metabolism is not just the transfer of elecrons, it is also dehydrogenation. Define dehydrogenation.

Answer 15

• A chemical reaction involving the loss of a hydrogen atom. (An oxidation that involves the loss of an electron + proton = Hydrogen Atom)

Question 16

This chemical reaction is an oxidation that involves the loss of an electron with a proton.

Answer 16

dehydrogenation

Question 17

Cellular respiration is the complete oxidation of what?

Answer 17

Glucose

Question 18

1. An atom that loses electrons is said to be _______
2. An atom that gains electron is said to be _______
3. Oxidation reactions are often coupled with reduction reactions in living systems, and these paired reactions are called
4. Cells utilize enzyme-facilitated redox reactions to take energy from food sources (energy metabolism) and convert it to

Answer 18

1. oxidized
2. reduced
3. redox reactions
4. ATP

Question 19

Part 1. Explain how an enzyme catalyzes a redox reaction involving an energy-rich substrate molecule, with the help of a cofactor, such as NAD+.

Answer 19

• In this reaction,

1. NAD+ accepts a Hydrogen atom (pair of electrons + proton)*from the substrate.* To form NADH!!!!
2. The oxidized product is now released from the enzyme’s active site, as is NADH!!!

Question 20

Part 2. An enzyme catalyzes a redox reaction involving an energy-rich substrate molecule, with the help of a cofactor.

• At the end of this process, high-energy electrons from the initial chemical bonds have lost much of their energy, and these depleted electrons are transferred to a final electron acceptor.

1. When this acceptor is oxygen, the process is called ______
2. When the final electron acceptor is an inorganic molecule other than oxygen, the process is called _______
3. When it is an organic molecule, the process is called ______

Answer 20

1. Aerobic respiration
2. Anaerobic respiration
3. Fermentation

Question 21

The process that results in the complete oxidation of glucose using oxygen as the final electron acceptor. Oxygen acts as the final electron acceptor for an electron transport chain that produces a proton gradient for the chemiosmotic synthesis of ATP.

.

Answer 21

In cellular respiration, this process is called aerobic respiration.

Question 22

This process uses the electron transport to generate a proton gradient for chemiosmotic synthesis of ATP using a final electron acceptor other than oxygen.

Answer 22

Anaerobic respiration

Question 23

The enzyme-catalyzed extraction of energy from organic compounds without the involvement of oxygen.

Answer 23

Fermentation