Ch. 8 & 9 – Photosynthesis and Cellular Respiration

Ch. 8 & 9 – Photosynthesis and Cellular Respiration

A. All organisms require energy for survival.1. Ultimately, all of the energy in food comes from the sun.

I. Energy and Life

2. Autotrophs – organisms that make their own food using energy from the sun

a. Example: Plants, algae, and some bacteria can trap energy from the sun (light energy) and convert it into food (chemical energy)

I. Energy and Life

3. Heterotrophs – organisms that eat plants or other animals to get energy

b. Example: Animals and other organisms cannot trap sunlight directly for food; instead they eat green plants or animals for food.

I. Energy and Life

4. Why do organisms need energy? To move, breathe, reproduce

5. Why do cells need energy? Active transport, cell division, to make proteins

6. Where does energy come from? Food (carbohydrates = quick energy)

(lipid= long term energy)

I. Energy and Life

B. Two Types of Cellular Energy

I. Energy and Life

1. ATP (Adenosine Triphosphate) – a molecule with 3 phosphate groups, ribose (a sugar), and adenine (a nitrogen base).

I. Energy and Life

2. ADP (Adenosine Diphosphate) – a molecule with 2 phosphate groups, ribose (a sugar), and adenine (a nitrogen base).

a. ADP is created when ATP loses energy and a phosphate.

I. Energy and Life

ATP vs. ADPI. Energy and Life

3. How is energy released and stored?a. Energy is released by breaking the bond and

removing a phosphate.ATP ADP

b. Energy is stored by adding 1 phosphate to ADP.ADP ATP

I. Energy and Life

Energy

I. Energy and Life

4. Most cells only have a small quantity of ATP (just a few seconds worth)!

a. ATP is not efficient at storing energy for a long time.

b. Cells rely on the ability to make more ATP from ADP by using energy from carbohydrates and lipids.

I. Energy and Life

A. Photosynthesis – when an autotroph uses carbon dioxide, water, and sunlight to make glucose, with oxygen as a byproduct.

II. Photosynthesis

1. Photosynthesis Equation – CO2 + H2O + light energy C6H12O6 + O2

II. Photosynthesis

2. Chloroplast – organelle where photosynthesis occurs

3. Chlorophyll – Most common pigment in chloroplasts; it reflects green light

a. Must be present for photosynthesis to occur.

II. Photosynthesis

Photosynthesis has 2 stages or reactions:– Light dependent reactions– Light independent reactions (a.k.a. Calvin Cycle)

II. Photosynthesis

B. Two Steps of Photosynthesis1. Step One: Light Dependent Reactions

a. Require light!b. Chlorophyll absorbs

sunlight, which causes electrons to gain lots of energy; ATP (energy carrier) and NADPH

(electron carrier) are stored for light independent reactions.

II. Photosynthesis

NADP+ NADPH NADP+

II. Photosynthesis

c. Water molecules broken apart into hydrogen gas and oxygen gas.

- H2O + Light O2 + H2

- Oxygen is released as a byproduct to the atmosphere.

II. Photosynthesis

2. Step Two: Light Independent Reactions (A.K.A. The Calvin Cycle)

a. Does not require light!b. Carbon dioxide and hydrogen gas form glucose

(sugar), using energy from ATP and electrons from NADPH.CO2 + H2 C6H12O6

II. Photosynthesis

3. Factors That Influence Photosynthesis Ratea. Lack of Water

Example/Adaptation: Desert plants/conifers (pines) waxy coating

and needle “leaves” to reduce water loss

II. Photosynthesis

b. Temperature – Influences the activity of enzymes - Best around 35 degrees.

c. Intensity of Light (varies by plant)- Excess UV rays/sunlight can decrease photosynthesis.

II. Photosynthesis

Chapter 9: Cellular Respiration

• Plants—make food (sugar) through photosynthesis

• Animals and other organisms—get food by eating plants and animals

Energy Review

A. Cellular Respiration – glucose and food are broken down to make energy (ATP) in ALL organisms.1. Occurs in the mitochondria of eukaryotes. 2. Occurs in the cytoplasm of prokaryotes.

III. Cellular Respiration

3. Cellular Respiration Equation –

C6H12O6 + O2 CO2 + H2O + energy


B. Two Types of Cellular Respiration1. Aerobic Respiration – breaking down of glucose molecules into smaller pieces in the presence of oxygen to produce ATP


THREE STEPS OF AEROBIC RESPIRATION1. Glycolysis

2. Kreb’s/Citric Acid Cycle3. Electron Transport Chain (ETC)


2. Three Steps of Aerobic Respirationa. Glycolysis – occurs in cytoplasm; glucose is split in half, forming a pyruvate molecule

- 2 ATP released- electrons released and carried to mitochondria by NADH



b. Kreb’s/Citric Acid Cycle – occurs in the mitochondria; pyruvate is split into smaller pieces

- CO2 gas released (we breathe it out)- 2 ATP released- electrons released and stay in mitochondria


Cellular Respiration

FAD+ FADH FAD+

NAD+ NADH NAD+

c. Electron Transport Chain (ETC) – occurs in the mitochondria; electrons forced through the mitochondrial membrane

- 32 ATP released


- TOTAL ENERGY: 36 ATPIII. Cellular Respiration

3. Anaerobic Respiration – breaking down glucose molecules into smaller pieces in the absence of oxygen to produce ATP

XIII. Cellular Respiration

4. Two Steps of Anaerobic Respirationa. Glycolysis – occurs in cytoplasm; glucose

is split in half, forming a pyruvate molecule- 2 ATP released - electrons released and carried to mitochondria


b. Fermentation – breaking down pyruvate without oxygen


Two Types of Fermentation1. Lactic Acid Fermentation – pyruvate is broken down into lactic acid + ATP– 2 ATP release– Lactic acid builds up as in muscle cells and causes burning

sensation (muscle cramping) during strenuous exercise.

C-C-C + NADH H-C-C-C + ATP + NAD+pyruvate e’ carrier lactic acid energy carrier


2. Alcoholic Fermentation – pyruvate is broken down into alcohol, carbon dioxide, and ATP in yeast and bacterial cells

- 2 ATP released- Used in making bread and beer

C-C-C + NADH C-C-OH + CO2 + ATPPyruvate + e’ carrier alcohol + carbon + energy

dioxide


Eat Digestion Glycolysis

Citric acid cycle

Electron transport chain

Oxygen is present

No oxygen is present

Fermentation(anaerobic respiration)

Lactic acid fermentation

Alcoholic fermentation

In animals

In yeast

Aerobic respiration


_______ ________ ____________

__________________

________________________

____________________

____________________

_______________________________

____________________

____________________

_______________

__________________


Photosynthesis vs. Respirationfood synthesized food broken downrequires energy produces energyChloroplast mitochondria/cytoplasmOnly autotrophs Autotrophs and

heterotrophs (all living cells)

Documents

Ch. 8 & 9 – Photosynthesis and Cellular Respiration