light absorption sun gives off visible (white) light white light is actually a mixture of roy g biv...
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Light Absorption
• Sun gives off visible (white) light• White light is actually a mixture of ROY G BIV
– Red, Orange, Yellow, Green, Blue, Indigo, Violet
White lightHow do we know this?
Light Absorption
• Sun gives off visible (white) light• White light is actually a mixture of ROY G BIV
– Red, Orange, Yellow, Green, Blue, Indigo, Violet
• These colors are either reflected or absorbed by objects
• We see reflected light– Green leaves = reflect green light
I see a black car (although I’m really
seeing nothing).
Which color(s) reflects?None
Which color(s) absorb?All
The Full Spectrum of Energy from the Sun
Our eyes can only sense this small area called “visible light”
• Most plants have green leaves, which means they:– Reflect green light– Absorb other colors
• Energy in red and blue light most stimulates photosynthesis
Light & Photosynthesis
• Defined: process that converts solar energy into glucose• Who: Autotrophs (Plants, algae, some bacteria & protists)• What: Endothermic chemical reaction
– Requires energy & MORE energy absorbed• End Result:
1. Sugar (glucose) stored in plant2. Oxygen as a waste product
reactants products
Photosynthesis
O2
• Where: Thylakoid membranes of chloroplast• What happens?
1) Sunlight & enzymes bond ADP with P to make… ATP
2) Water (H2O) broken apart
• Hydrogen kept for later use; Oxygen is released as a waste• End result: ATP, H2, Oxygen
Stage 1: Light Dependent (Light Reactions)
H2O
H2O H2O
H2O
Stroma
enzymesenzymes
ADP
P
ADP
P
ATPATP
Thylakoids
60 seconds: Discuss with your neighbor
1) Are the products of photosynthesis on the left or right of the arrow?
2) Which reactant(s) are used during the light dependent stage?
3) Which product(s) are created during the light dependent stage?
reactants products
#2 #3
Stroma
• Where: Stroma (fluid interior) of chloroplast• What happens?
A) CO2 taken in
B) ATP & enzymes break apart CO2 + H2
C) C’s, O’s, and H’s recombine into C6H12O6 (Glucose)
Stage 2: Light Independent (Dark Reactions)
H2
H2
H2
H2
ATP
ATP
CO2
CO2
CO2
CO2
CO2
CO2 H2
H2
COOCOO
COO
COO
COO
COOenzymes
enzymes
HH
HHHH
HH
HH
HH
What’s the formula for glucose?
C6H12O6
60 seconds: Discuss with your neighbor
1) Which reactant(s) are used during the light independent stage?
2) Which product(s) are created during the light independent stage?
reactants products
#1 #2
Connection between photosynthesis & respiration
• Plants– Create glucose through photosynthesis– Glucose is used to make ATP through cellular
respiration
Plant Cell
glucose
glucosechloroplast
chloroplast ATP
ATP
mitochondrion
mitochondrion
Connection between photosynthesis & respiration
• Animals– Plants create glucose through photosynthesis– Animals eat the plants – Glucose is used to make ATP through cellular
respiration
Glucose
mitochondrionATP
Glucose(from food)
Review1) Which color(s) is/are absorbed by a typical red
apple?2) Which color(s) is/are reflected by a typical red
apple?3) Which color light produces the highest rates of
photosynthesis?4) What is used during the light dependent
reactions?5) What is created during the light dependent
reactions?6) What is used during the light independent
reactions?7) What is created during the light independent
reactions?8) True or False: Plants are the only
photosynthetic organisms.
1) Which color(s) is/are absorbed by a typical red apple?• All the colors except red
2) Which color(s) is/are reflected by a typical red apple?• Red
3) Which color light produces the highest rates of photosynthesis?• Blue
4) What is used during the light dependent reactions?• *H2O | Light Energy | Enzymes | ADP | P
5) What is created during the light dependent reactions?• *O2 | H2 | ATP (the O2 and H2 are created when the water splits)
6) What is used during the light independent reactions?• *CO2 | H2 | ATP | Enzymes
7) What is created during the light independent reactions?• *C6H12O6
8) True or False: Plants are the only photosynthetic organisms. False
Answers to Review