Photosynthesis Why its Important for Biological Energy Free

Photosynthesis Why it’s Important for Biological Energy Free powerpoints at http: //www. worldofteaching. com

Overview • Biology: Study of Living Things – Includes: Plants, Animals, Bacteria etc. • All energy on earth comes from the sun. • We depend on: – Plants – Algae (underwater plants) – Cyanobacteria (photosynthetic bacteria) • To provide this energy to us!

Overview

• Carbon dioxide and water are taken in by plants • Plants absorb light energy and convert it to a usable form. – ATP • Energy is used to “fix” carbon dioxide into sugar molecules – Chemical energy • Sugar is converted to starch and stored for use by the plant, and by animals when they eat plants.

Chloroplasts • All light energy is transformed into sugar (chemical energy) in the chloroplasts…. The green part of the leaf. Image source: http: //www. daviddarling. info/encyclopedia/C/chloroplasts. html

Chloroplasts • Chlorophyll molecules are embedded in the thylakoid membrane • Act like a light “antenna” • These molecules can absorb sunlight energy. Image from Biology 11: College Preparation. Pg 73. Nelson, Toronto. 2003.

Light (dependent)Reactions • Happen ONLY in sunlight – Hence they depend on light! 1. Light is absorbed by chlorophyll molecules 2. The energy generates molecules of ATP Image from: Biology 11: College Preparation. Pg 74. Nelson, Toronto. 2003.

Overall Reaction What is the equation for photosynthesis? carbon dioxide + water glucose + oxygen + energy 6 CO 2 + 6 H 2 O C 6 H 12 O 6 + 6 O 2 + energy

Summary Image from: Biology 11: College Preparation. Pg 74. Nelson, Toronto. 2003.

Why do leaves turn brown in the fall? • It’s all about pigments! • Write a short description of why you think they turn brown and fall off. • If you wrote that Leaves turn brown and fall off because photosynthesis does not occur efficiently in the winter with less sunlight, so the tree is trying to save up energy by holding chlorophyll in the tree trunk and not in the leaves…. Then you’re right!

What is Respiration? • Respiration is the opposite of photosynthesis. • It’s how we and all other animals receive energy. • Glucose + Oxygen = Carbon Dioxide + Water + Energy • C 6 H 12 O 6+6 O 2=6 CO 2+6 H 2 O+Energy

The Energy is in the form of ATP. Structure of ATP adenosine Pi Pi Pi

Formation of ATP is made when another molecule called adenosine diphosphate (ADP) is bonded to a third inorganic phosphate (Pi) using the energy released from glucose.

Energy from respiration adenosine Pi Pi + Pi Enzymes adenosine Pi Pi Pi Energy Rich bond formed

Summary ATP cellular respiration energy (out) energy (in) energy (out) cell activities ADP + Pi The whole process is an enzyme controlled reaction.

ATP production – summary glucose 2 ADP + 2 Pi = 2 ATP pyruvic acid 36 ADP + 36 Pi = 36 ATP carbon dioxide + water