Download presentation
Presentation is loading. Please wait.
1
Photosynthesis light reaction
2
Cell Energy: Energy for living things comes from food which comes from the sun.
3
Organisms that CANNOT use the sun’s energy to make food—heterotrophs
Ex: animals and most microorganisms
4
Producers: organisms that use light energy from the sun to produce food—autotrophs Ex: plants and some microorganisms (some bacteria and protists)
5
Where photosynthesis takes place
Leaf Anatomy Protects the leaf Where photosynthesis takes place Lets CO2 in and O2 out
6
More specifically, photosynthesis occurs in the chloroplasts of leaf
granum
7
Chloroplast Structure: Structure:
8
(These look yellow, orange, and red). As chlorophyll dies in the
The main energy absorbing molecule in chloroplasts is _____________ ______________ are plant pigments too. (These look yellow, orange, and red). As chlorophyll dies in the fall, the green color fades and is replaced by carotenoids CHLOROPHYLL CAROTENOIDS
9
Chlorophyll absorbs mostly red and blue wavelengths of light
Red and blue absorbed Green is reflected
10
Photosynthesis Overview
11
Two Main Stages of Photosynthesis
Light-Independent Reactions (Calvin Cycle) Light- Dependent Reactions
12
Goal of the Light-Dependent Reaction:
Sun’s energy is absorbed in the thylakoid & changed into chemical energy in ATP & NADPH in stroma
13
5 steps of light rxn Light strikes thylakoid & hits chlorophyll causing electrons become excited.
14
5 steps of light rxn 2. Electrons jump from chlorophyll to chlorophyll through thylakoid membrane (electron transport chain). NADP+ picks up high energy e- & H+ to become NADPH.
16
H2O is split by light (photolysis)– electrons are given back to chlorophyll, H+ collects, & O2 is released (waste product you breathe)
17
4. H+ builds up inside thylakoid. 5
4. H+ builds up inside thylakoid. 5. H+ pass through transport protein (ATP synthase) which adds P to ADP forming ATP.
18
At the end of the Light-Dependent Reactions…
19
Summary of Light Rxn Video clip Using light energy ADP NADP+ H2O changed into ATP NADPH H+ & O2
20
Talk to a Neighbor… Using the following diagram, walk your partner through the 5 steps of the light- dependent reactions
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.