Ch. 8 - Photosynthesis

Question 1

What is photosynthesis?

Answer 1

The process of using the energy from sunlight to power the synthesis of carbohydrates.

Question 2

What is the reaction formula for photosynthesis?

Answer 2

CO2 + H2O + sunlight -> C6H12O6 + O2 + H2O

Question 3

Through what does gas exchange in a leaf occur?

Answer 3

Through pores called stomata.

Question 4

In what cells does photosynthesis take place?

Answer 4

Mesophyll cells.

Question 5

What are the three main stages of photosynthesis?

Answer 5

1) Capturing energy from sunlight.
2) Using energy to make ATP and NADPH
3) Carbon fixation

Question 6

What is the purpose of carbon fixation?

Answer 6

To use synthesized ATP and NADPH to make organic molecules from atmospheric CO2.

Question 7

What are the first two stages of photosynthesis called?

Answer 7

Light reactions.

Question 8

What is the third stage of photosynthesis called?

Answer 8

The Calvin cycle.

Question 9

In plants, photosynthesis only occurs where?

Answer 9

In the chloroplast.

Question 10

How many membranes compose chloroplasts?

Answer 10

Outer and inner.

Question 11

What are grana and where are they located?

Answer 11

Compartments of stacked membranes.

Located in the chloroplasts.

Question 12

What is a thylakoid?

What is the difference between a thylakoid and a grana?

Answer 12

A flattened sack.

A grana is comprised of a stack of thylakoids.

Question 13

What is imbedded in the membrane of the thylakoids?

Answer 13

Photosynthetic pigments (Chlorophylls and accessory pigments)

Question 14

What are photosystems?

Answer 14

The pigments clustered together.

Question 15

What is the stroma?

Answer 15

A semi-fluid matrix surrounding the grana.

Question 16

What is contained in the stroma?

What are they used for?

Answer 16

Contains enzymes.

Used to assemble the carbon molecules.

Question 17

How are mitochondria and chloroplasts similar?

Answer 17

They each contain their own DNA.

Question 18

What are light reactions?

Answer 18

The initial set of reactions that are dependent on light.

Question 19

What are dark reactions?

Answer 19

The second set of reactions that were independent of light, but limited by CO2.

Question 20

What is light a part of?

Answer 20

The electromagnetic spectrum.

Question 21

How do electromagnetic energy travel?

Answer 21

In waves

Question 22

What is a wavelength?

Answer 22

The distance from the peak of one wave to the peak of the next wave

Question 23

How are wavelength and energy level related?

Answer 23

The shorter the wavelength the higher the energy.

Question 24

What are the 8 types of wavelengths?

Answer 24

• Radio waves: 1-100 meters long (lowest energy)
• Microwaves: About 1cm (higher energy)
• Infrared: between 800nm (nanometer) - 10um (micrometer)
• Visible light: 400-740nm
• Ultraviolet: About 10nm
• X-rays: About 1nm
• Gamma rays: < 0.001 nm

Question 25

List visible light in order from largest wavelength to lowest.

Answer 25

``` Red -> 740nm Orange Yellow Green Blue Indigo Violet -> 400nm ```

Question 26

How does light energy travel?

Answer 26

In small packets called photons.

Question 27

What are the two properties that light has?

Answer 27

Properties of both waves and particles.

Question 28

What is important about photons and the amount of energy they posses?

Answer 28

The shorter the wavelength the higher energy the photon will contain.

Question 29

What are the 2 things that can happen when a photon strikes a molecule?

Answer 29

1) The energy is lost as heat | 2) The energy can be absorbed by the electrons of the molecule.

Question 30

What happens if the electron of a molecule absorbs photons?

Answer 30

The energy can cause the electron to jump into a higher energy level.

Question 31

What are pigments?

Answer 31

Molecules that absorb light energy.

Question 32

How do you absorb light energy?

Answer 32

Pigments.

Question 33

What is the difference between Chlorophyll a and Chlorophyll b?

Answer 33

Just a substitution at one location on the ring.

Question 34

What is chlorophyll a?

Answer 34

The primary pigment used in virtually all photosynthetic organisms.

Question 35

What are chlorophyll and carotenoids responsible for?

Answer 35

Absorbing light energy.

Question 36

How are chlorophyll and carotenoids different?

Answer 36

They absorb light from different spectrums.

Question 37

What are the pigments in carotenoids called? Why?

Answer 37

Accessory pigments. They allow for more efficient usage of the energy from sunlight.

Question 38

What is a photosystem?

Answer 38

A cluster of chlorophyll and accessory pigment molecules imbedded in a membrane.

Question 39

Where are the photosystems imbedded in photosynthetic bacteria? In photosynthetic eukaryotes?

Answer 39

In the plasma membrane. In the thylakoid of the chloroplasts.

Question 40

What 2 parts compose a photosystem?

Answer 40

1) Antenna complex | 2) Reaction center

Question 41

What is the antenna complex in a photosystem? What is the function?

Answer 41

A cluster of chlorophyll molecules. Captures energy. The captured energy is transferred from molecule to molecule until the energy reaches the reaction center.

Question 42

What is the reaction center of a photosystem made of? What is the function?

Answer 42

One or two chlorophyll molecules in a transmembrane protein matrix. To eject high energy electrons to start the next series of steps of photosynthesis.

Question 43

What are the 4 main steps of light reactions?

Answer 43

1) Primary photo event 2) Charge separation 3) Making ATP 4) Making NADP