How Energy Cycles: Photosynthesis & Cellular Respiration

Biology

How Energy Cycles

How Energy is Cycled

Photosynthesis:A Review

Photosynthesis

Only in plants (Some bacteria/some protists)

Occurs in those cells that have chloroplasts

Chlorophyll – necessary for chloroplasts to work correctly

Formula:

Light + CO2+ H2O C6H12O6 + O2

Photosynthesis, cont.

3 (simplified) stages1. Energy from sunlight is captured by

chloroplasts

2. Light energy is converted into chemical energy by chlorophyll enzymes

3. ATP and NADPH are formed

Rate of Photosynthesis

What factors do you think affect the rate of photosynthesis?

Light intensity Carbon dioxide Temperature Amount of water available

Cellular Respiration

*The process that releases energy by breaking down glucose and other food molecules

* Occurs in ALL living cells

Understanding Cellular Respiration:

First we need to understand that while photosynthesis happens in plants and some bacteria/protists (those which can have chlorophyll present), cellular respiration happens in all cells.

What do most cells need to have in order for cellular respiration to take place…

Mitochondria!!:

Cytoplasm: glycolysis

Matrix (inner space): Prep Step and the Kreb’s Cycle

Cristae (the folds): contains the carriers used in The Electron Transport System

Aerobic (Oxygen)Cellular Respiration

Occurs in the presence of oxygen

Major energy releasing process

Occurs in 3 stages: GLYCOLYSIS KREBS CYCLE ELECTRON TRANSPORT

CHAIN

FORMULA: C6H12O6 + O2 CO2 + H2O + ATPWhat does this formula remind you of?

GLYCOLYSIS Occurs in the cytoplasm

1. Glucose converted into pyruvic acid

2. Produces a net total

of 2 ATP molecules

3. 2 NADH molecules

are formed

4. Does not require

oxygen

Krebs Cycle (aerobic) Occurs in

mitochondria Pyruvic acid from

glycolysis is broken down into CO2

1 molecule of ATP is produced

ADP ATP

Energy released

-P

Energy stored

+P

Electron Transport Chain

The Krebs Cycle generates high-energy electrons that are passed to the electron transport chain

Here they are used to change ADP to ATP Water is formed

Anaerobic Cellular Respiration

Without oxygen Also called

fermentation Yields 2 molecules of

ATP Glycolysis is followed

by either: lactic acid fermentation

Alcoholic fermentation

Lactic Acid Fermentation

• Lactic acid produced

• Build up of lactic acid causes you to have sore muscles after working out

Alcoholic Fermentation

• Ethyl alcohol is produced

• Fermentation- used to make beer and wine

• Bread Baking- Yeast are anaerobic organisms