Photosynthesis

Question 1

Autotroph

Answer 1

An organism that creates it’s own food.

Question 2

Chemoautotroph

Answer 2

An organism that derives energy from oxidation of inorganic compounds.

Question 3

Heterotroph

Answer 3

An organism that cannot make it’s own food.

Question 4

Cellular respiration

Answer 4

A catabolic pathway in which organic molecules are broken down to release energy for use by the cell.

Question 5

Photosynthesis

Answer 5

Two-phase
Anabolic pathway in which the suns light energy is converted to chemical energy to be used by the cell.

Question 6

Calvin Cycle

Answer 6

Light-independent reactions during phase two of photosynthesis in which energy is stored in organic molecules as glucose.

Question 7

Light Dependent Reactions

Answer 7

The light-dependent reactions produce oxygen gas and convert ADP and NADP+ into the energy carriers ATP and NADPH.
ATP and NADPH provide the energy needed to build high-energy sugars from low-energy carbon dioxide in the light-independent reactions.

Question 8

Factors affecting Photosynthesis

Answer 8

1. Temperature: Too hot or too cold, photosynthesis slows down or stops
2. Water: Lack of water slows down or stops photosynthesis
3. Light Intensity: Increased light = increase in rate, up to a certain level
4. Amount of CO2: More carbon dioxide = faster rate of photosynthesis

Question 9

In photosynthesis, what are the two major reactions that take place?

Answer 9

1. Light dependent reactions
2. Light independent reactions

Question 10

In aerobic cellular respiration, what three major steps are involved?

Answer 10

1. Glycosis
2. Krebs Cycle
3. Electron transport chain

Question 11

Formula for Photosynthesis

Answer 11

6CO2 + 6H2O → C6H12O6 + 6O2

Question 12

Formula for Cellular Respiration

Answer 12

C6H12O6 + 6 O2 –> 6 CO2 + 6 H2O + ATP

Question 13

How does ADP become ATP and vice versa?

Answer 13

A phosphate is broken off (ATP –> ADP)
A phosphate is added (ADP –> ATP)

Question 14

Photosystem II

Answer 14

Pigments absorb light
High energy electrons are passed to electron transport chain
As light continues to shine, more and more electrons are passed to transport chain
Enzymes break H2O into 2 electrons, 2 H+ ions and 1 oxygen atom

Question 15

Electron transport chain

Answer 15

Electrons move into chain
Energy from electrons is used by proteins(ATP synthase) to pump H+ ions from stroma to thylakoid
(Electrons then pass to photosystem I)

Question 16

Photosystem I

Answer 16

Electrons now have less energy (it was used to pump H+ across thylakoid membrane)
Pigments use energy from light to reenergize electrons

NADP+ molecules in the stroma pick up the high-energy electrons and H+ ions at the outer surface of the thylakoid membrane to become NADPH.
(These will be used in the light independent reactions)

Question 17

Light-Independent Reactions

Answer 17

During light-independent reactions, ATP and NADPH molecules produced in the light-dependent reactions are used to produce high-energy sugars from carbon dioxide.
No light is required to power the light-independent reactions.
The light-independent reactions take place outside the thylakoids, in the stroma.

Question 18

ATP synthase

Answer 18

ATP-making enzyme
ATP synthase adds a phosphate to a molecule called ADP to make ATP.

Question 19

What is ATP used as?

Answer 19

ATP is used as an energy source for many chemical reactions in cells.

Question 20

NADP+

Answer 20

Molecule used for energy transport within the cell

When two electrons and a hydrogen are added to NADP+, it becomes NADPH

Question 21

NAPDH

Answer 21

A biological compound used to fuel many processes within a cell.
NADPH is produced when a molecule of NADP+ has one hydrogen and two electrons added to it.
NADPH can then donate its hydrogen, electrons, and energy to an enzyme or other molecule to fuel a cell process.

Question 22

ATP

Answer 22

A molecule that is made up of adenosine and three phosphates.
Cells use ATP as a source of energy

Question 23

Chlorophyll

Answer 23

The main light-absorbing molecule used to power photosynthesis.
Chlorophyll absorbs red and blue light, but it reflects green light.

(This is why many plants appear green.)

Question 24

Stroma

Answer 24

The fluid found inside of a chloroplast.

Question 25

Thylakoid

Answer 25

Pancake-like, membrane-bound structures that are found inside chloroplasts.

Question 26

Grana

Answer 26

A stack of thylakoids.

Question 27

ADP

Answer 27

A molecule that is made up of adenosine and two phosphates.

Question 28

Chloroplast

Answer 28

Specialized organelles found within plant and algae cells.
Conducts photosynthesis.

Question 29

Where is energy stored in ATP?

Answer 29

In the bonds between the 2nd and 3rd phosphate groups

Question 30

What are the reactants and products of light-dependent reactions

Answer 30

Reactants- NADP, ADP, water molecules
Products- ATP, NADPH, oxygen

Question 31

Energy

Answer 31

The ability to do work

Question 32

What is NADP+/NADPH used for in photosynthesis?

Answer 32

NADPH supplies electrons for other chemical reactions in the cell

(NADP+ is NADPH but without the electrons)

Question 33

Why do leaves “change color” in the fall?

Answer 33

The chlorophyll breaks down

Question 34

What happens when chlorophyll is struck by sunlight?

Answer 34

It energizes electrons within that molecule.