Chapter 9- Cellular Respiration

Question 1

Where do organisms get the energy they need for life processes?

Answer 1

Food

Question 2

What is a calorie?

A Calorie?

Answer 2

calorie- amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius

Calorie- a kilocalorie: 1000 calories

Question 3

Carbohydrates and proteins contain how much energy per gram? What is the energy content of fats? Why do foods differ in the amount of energy they contain?

Answer 3

a.
Carbs and proteins- 4000 calories (4 Calories)

b.
Fats- 9000 calories (9 Calories)

c.It is dependent upon the composition of the food. Some foods have more carbohydrates than others, etc.

Question 4

Define cellular respiration.

Answer 4

Cellular Respiration- The process that releases energy from food in the presence of oxygen.

Question 5

What are the 3 stages of cellular respiration and where in the cell does each stage occur?

Answer 5

a.
Glycolysis- cytoplasm

b.
Krebs Cycle- matrix

c.Electron Transport Chain- Inner mitochondrial membrane

Question 6

Compare photosynthesis and cellular respiration

Answer 6

Photosynthesis
Function: energy capture
Location: chloroplasts
Reactants: CO2, H2O, light
Products: oxygen, glucose

Cellular Respiration
energy release
cytoplasm & mitochondria
glucose and oxygen
CO2, H2O, energy

Energy flows in opposite directions
Equations are reverse of each other

Question 7

Write the equation for cellular respiration in both words and symbols

Answer 7

Symbols: 6O2 + C6H12O6 → 6CO2+6H2O+Energy

Words: Oxygen + Glucose → Carbon dioxide+Water+Energy

Question 8

What is the difference between “aerobic” and “anaerobic”? Identify each stage of cellular respiration as either aerobic or anaerobic.

Answer 8

Aerobic- oxygen is present
Krebs Cycle
ETC

Anaerobic- no oxygen present
Glycolysis

Question 9

Describe what happens during glycolysis

Answer 9

1 molecule of glucose (6 carbon compound) is transformed into 2 molecules of pyruvic acid (3 carbon compound)

Question 10

Where does glycolysis occur in the cell?

Answer 10

Cytoplasm

Question 11

How many ATP’s are used to jumpstart glycolysis?

Answer 11

2 ATP

Question 12

To which electron carrier are high-energy electrons passed during glycolysis?

Answer 12

NAD+

Question 13

What is the net energy gain in glycolysis?

Answer 13

2 ATP

Question 14

Where do products of glycolysis go?

Answer 14

2 NADH goes to ETC
4 ATP
-2 go back through glycolysis
2 Pyruvic Acid goes to Krebs Cycle

Question 15

Where in the cell does the Krebs Cycle occur?

Answer 15

Matrix

Question 16

What happens during the Krebs Cycle?

Answer 16

Pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.

Question 17

Is the Krebs cycle aerobic or anaerobic?

Answer 17

aerobic

Question 18

What product of glycolysis is used to start the Krebs Cycle?

Answer 18

2 pyruvic acid

Question 19

Into what 2 products is pyruvate broken down into in the Krebs cycle?

Answer 19

NADH and FADH+

Question 20

Acetyl-CoA combines with what 4-carbon compound in the Krebs cycle?

Answer 20

Succinate

Question 21

Name 4 products of the Krebs cycle.

Answer 21

NADH
FADH2
ATP
CO2

Question 22

How does the ETC use the high-energy electrons from glycolysis and the Krebs cycle?

Answer 22

To convert ADP to ATP

Question 23

As electrons pass through the ETC, a gradient of H+ ions build up where in the mitochondria?

Answer 23

Intermembrane space

Question 24

How does the cell use the charge differences that build up across the inner mitochondrial membrane during cellular respiration?

Answer 24

Chemiosmosis- The charge differences forces H+ ions through channels in the enzymes, causing the ATP synthases to spin. The enzymes grab an ADP molecule and attaches a phosphate group, producing ATP.

Question 25

How many molecules of ATP are produced in the entire breakdown of glucose?

Answer 25

36 ATP molecules

Question 26

What is fermentation? Name 2 types of this process discussed in class.

Answer 26

A process that makes it possible to continue to produce ATP after glycolysis if oxygen is not available.

Alcoholic Fermentation

Lactic Acid Fermentation

Question 27

Which form of fermentation is carried out by your body?

Answer 27

Lactic Acid Fermentation

Question 28

Is fermentation aerobic or anaerobic?

Answer 28

anaerobic

Question 29

What are 3 main sources of ATP available for human muscle cells?

Answer 29

ATP already in muscles

ATP made by lactic acid fermentation

ATP produced by cellular respiration

Question 30

During a race, how do your muscle cells produce ATP after the store of ATP in muscles is used?

Answer 30

It then uses ATP made by lactic acid fermentation which is usually enough energy to last 90 seconds.

Question 31

Why does a sprinter have an oxygen debt to repay after the race is over?

Answer 31

The only way to get rid of lactic acid is in a chemical pathway that requires extra oxygen.

Question 32

A runner needs more energy for a longer race. How does the body generate the necessary ATP?

Answer 32

It uses ATP made in cellular respiration

Question 33

Why are aerobic forms of exercise so beneficial for weight control?

Answer 33

The stores of glycogen are usually enough to last about 15 to 20 minutes- after that the body begins to break down other stored molecules (including fats) for energy.