Photosynthesis and Cellular Respiration

Chapters 6 and 7

Photosynthesis

• Energy from the sun allows plants to grow• Animals eat plants, acquire energy from the

plants• All energy originally from the sun

Photosynthesis

• Two categories of organisms:–Autotrophs - use energy from sunlight to

make organic compounds.–Heterotrophs - organisms that must get

energy from food instead of directly from sunlight

Photosynthesis

• Photosynthesis converts light energy from the sun into chemical energy in the form of organic compounds.

Where does photosynthesis occur?

Classwork

• Define and sketch:• Chloroplasts• Thylakoids• Grana• Stroma

Photosynthesis

Photosynthesis

• Photosynthesis can be divided into two stages:1. Light Reactions – light energy is converted

to chemical energy (light dependent)2. Calvin Cycle – organic compounds are

formed (light independent)

Photosynthesis

Glucose (sugar)

Pigments (Part of Light Reaction)• Pigments – compounds that absorb light• Chloroplast pigments:– Chlorophylls – chlorophyll a is directly involved in light

reactions of photosynthesis– Chlorophyll b – accessory pigment– Carotenoids – accessory pigment (yellow, orange &

brown)

Light Reactions

• Uses light energy• Converts light energy to chemical energy

through photosystems• Makes ATP (energy!) and NADPH• Converts H2O into O2

• Takes place in the thylakoid membrane of the chloroplast

Photosynthesis Video

https://www.youtube.com/watch?v=g78utcLQrJ4

Light Reactions

• Photosystem II and Photosystem I• Moves electrons

The Calvin Cycle

• Does not require light energy• Uses energy produced in the light reactions• Produces C6H12O6 (sugar) from CO2 (carbon

dioxide)

Group WorkChloroplasts• What is the structure of a chloroplast?• Where are chloroplasts located?• What are grana? Thylakoids? Thylakoid membranes?• Where do the reactions of each stage of photosynthesis

occur?Products and Reactants of Photosynthesis• What are the two stages of photosynthesis?• What are the products and reactants of photosynthesis?• What are the products and reactants of the light reactions? • What are the products and reactants of the Calvin Cycle?

Photosynthesis Crash Course

https://youtu.be/sQK3Yr4Sc_k

CH 7: Cellular Respiration

• Cellular respiration – the complex process in which cells make ATP by breaking down organic compounds.

Cellular Respiration

• Both autotrophs and heterotrophs use cellular respiration.

• The products of cellular respiration are the reactants in photosynthesis; conversely, the products of photosynthesis are reactants in cellular respiration.

Cellular Respiration

• Cellular respiration can be divided into two stages:1. Glycolysis2. Aerobic respiration

Glycolysis• Takes place in the cytosol of cells. • One six-carbon glucose molecule is oxidized to

form two three-carbon pyruvic acid molecules.

• A net yield of two ATP molecules is produced.

Aerobic Respiration

• Second stage of cellular respiration.• Aerobic respiration takes place in the

mitochondria. • Can be divided into two steps:

1. Krebs Cycle2. Electron Transport Chain

Krebs Cycle

• Breaks down Acetyl CoA (from pyruvic acid) to produce CO2, hydrogen atoms, and ATP.

• Occurs in mitochondrial matrix.

Electron Transport Chain

• Second stage of aerobic respiration.

• Occurs in inner mitochondrial membrane.

• Transports electrons to make LOTS of ATP (38 total for ETC and Krebs)

• Uses oxygen as the final electron acceptor to make water.

Electron Transport Chain

A Summary Of Cellular Respiration

Fermentation

• Aerobic respiration can only take place when oxygen is present.

• When oxygen is not present, fermentation occurs.

• Two types of fermentation– Lactic acid–Alcoholic

Aerobic vs. Anaerobic

Fermentation

• Cellular Respiration Crash Course:

https://youtu.be/00jbG_cfGuQ

Self Quiz/ Classwork

1. What are the products and reactants of cellular respiration?

2. What types of organisms do cellular respiration?3. What two main steps can cellular respiration be

broken down into? How can this be broken down even further?

4. Why is oxygen so important in cellular respiration? What happens when there is no oxygen present?

5. How are the products and reactants of photosynthesis and cellular respiration related?