Photosynthesis

Photosynthesis: Step 1 – Light-Dependent ReactionSunlight is used to split water into hydrogen

(H) and oxygen (O). The Oxygen is released to the atmosphere.

Photosynthesis: Step 2 – Light-Independent

Reaction

This step is also called the Calvin Cycle or Light Independent Reaction because it does not need light.

CO2 combines with the hydrogen (H) released during step 1 to form C6H12O6 (glucose)

What affects the rate of photosynthesis?Amount of :- sunlight- CO2

- H2O

- temperatureAll the reactions of photosynthesis are controlled by enzymes. Temperatures above or below the optimum temperature will slow down the chemical reactions.

Pigments of Photosynthesis

Pigments are molecules that absorb specific wavelengths (energies) of light and reflect all others.

Chlorophyll is the main molecule in charge of capturing the energy from sunlight.

•Chlorophyll a absorbs …………….. light best.•Chlorophyll b absorbs ……………. light best.

•Why do plants look green?

•THEY RELFECT GREEN LIGHT!!!

Other Pigments Present in Plants

Carotenoids: Orange-Red

Xanthophyls: Yellow

Anthocyanins: Red-Blue

GET YOUR CLICKERS!

What is the process in which autotrophs trap the energy from the sun and store this energy in molecules such as carbohydrates.

1 2 3 4

0%

50%50%

0%

1. Predation2. Metabolism3. Cell Respiration4. Photosynthesis

Which of the following is not needed for photosynthesis?

1 2 3 4

0% 0%

17%

83%

1. Water2. Sugar3. Carbon Dioxide4. Sunlight

In addition to light and chlorophyll, photosynthesis

requires

1 2 3 4

3%

31%

66%

0%

1. Water and oxygen2. Water and sugars3. Oxygen and Carbon

Dioxide4. Water and carbon

dioxide

The leaves of a plant are green because chlorophyll :

1 2 3 4

0%

21%

79%

0%

1. Reflects blue light2. Absorbs blue light3. Reflects green light4. Absorbs green light

Which is not a function of NADPH?

To carry

energy for o

the...

To carry

2 high energy e...

To act as

a carri

er molecu

le

To carry

a hydrogen io

n

0% 0%0%0%

1. To carry energy for other organelles to do work

2. To carry 2 high energy electrons

3. To act as a carrier molecule

4. To carry a hydrogen ion

Chloroplasts do not contain which of the following

structures?

Mito

chondria

Thylakoids

Stro

ma

Chlorophyll

Pigments

75%

0% 0%0%

25%

1. Mitochondria2. Thylakoids3. Stroma4. Chlorophyll5. Pigments

10

Energy from the sun is collected during the:

Light-i

ndependent react.

..

Light-d

ependent reacti

ons

Thylakoid re

actions

Krebs C

ycle

25%

0%0%

75%1. Light-independent reactions

2. Light-dependent reactions

3. Thylakoid reactions

4. Krebs Cycle

10

Glucose is created during this step of photosynthesis.

Light-i

ndependent rea...

Light-d

ependent reacti

on

Thylakoid re

actions

Kre

bs Cyc

le

71%

6%18%

6%

1. Light-independent reaction

2. Light-dependent reaction

3. Thylakoid reactions

4. Krebs Cycle

10

Which of the following would not directly impact the growth of a plant?

Spectr

um of light

Concentra

tion of oxy

gen

Concentra

tion of carb

o...

Availabilit

y of water

Temperatu

re

6%

65%

18%

6%6%

1. Spectrum of light2. Concentration of

oxygen3. Concentration of

carbon dioxide4. Availability of water5. Temperature

10

Which of the following is NOT produced in the light-dependent

reactions?

NADPH

Suga

rs

Hyd

rogen Io

ns ATP

6%12%

18%

65%

1. NADPH2. Sugars3. Hydrogen Ions4. ATP

10