Chapter 8

Photosynthesis

&

Chapter 9

Cellular Respiration

Where does the energy come from? Ultimate source of energy = sun What is an Autotroph? an organism that

makes its own food for energy (directly) What is a Heterotroph? An organism that

can’t directly make its own food, but must get food.

FOOD (Glucose)

ATP - adenosine triphosphate Energy to make ATP comes from the

energy released from food Made by adding 1 phosphoric acid to ADP

(Adenosine diphosphate).

Cellular Fuel

Used battery

Charged battery

Photosynthesis The process of making food using energy

from the sun. Converting solar (radiant or light) energy into

chemical energy. Plants, algae, and photosynthetic bacteria

History of photosynthesis Van Helmont – most of a plants mass

comes from water.

History of Photosynthesis Priestley – plants produce a substance

(oxygen) that keep candles burning.

History of Photosynthesis Ingenhousz –green parts of plants produce

oxygen in the light but not in the dark.

Photosynthesis 6 CO2 + 6 H2O + light energy

C6H12O6 + 6 O2

Carbon dioxide + water + light glucose + oxygen

Not only does photosynthesis need light, it also requires chlorophyll (light absorbing pigment that reflects green light)

Chloroplasts=solar panels

6 CO2 + 6 H2O + light energy C6H12O6 + 6 O2

6

6

6

Cellular Respiration The process of releasing energy by breaking down

glucose and other food molecules: With oxygen. aerobic respiration Without oxygen: anaerobic respiration

C6H12O6 + 6 O2

6 CO2 + 6 H2O + energy

glucose + oxygen Carbon dioxide + water + ATP

Mitochondria =electric company

3 stages of cellular respiration

Without oxygen

Fermentation – anaerobic respiration NADH passes electrons back to pyruvic

acid to become NAD+ again. Allows glycolysis to continue = 2 more ATP

Alcoholic fermentation –make alcohol Carbon dioxide and ethyl alcohol = wastes

Lactic acid fermentation – rapid exercise Lactic acid = waste

Causes sore muscles,used to make cheese and yogurt.

With Oxygen – Aerobic respiration Cellular respiration continues…

Maximum ATP production per glucose Anaerobic respiration: 2 ATP (glycolysis)

Aerobic respiration: 2 ATP (glycolysis)

2 ATP (Krebs cycle)

+ 32 ATP (ETC)

36 ATP (all 3 steps)

(Only 2 are made in anaerobic respiration while another 34 are made in aerobic respiration alone)

ATP production during exercise Sprint –

0 – few seconds stored ATP Up to 90 seconds lactic acid fermentation

Why? Not bringing in oxygen fast enough to keep up. Panting restores the oxygen debt.

Paced – 0 – 90 seconds stored ATP 1.5 – 15/20 min carbohydrate glycogen After 20 min. fat molecules