Photosynthesis Chapter 5 Summary

Question 1

Photosynthesis

Answer 1

Converts kinetic energy in light to potential energy in the covalent bonds of glucose

Question 2

Photosynthetic organisms

Answer 2

1. Plants
2. Algae
3. Some microorganisms

Question 3

Photosynthesis builds what from what

Answer 3

Builds carbohydrates from carbon dioxide and water

Question 4

What type of reaction is P/S

Answer 4

Redox

Question 5

REdox reaction of P/S

Answer 5

Water = oxidized ( looses an electron when split by chlorophyll to replace its own lost electron)
Carbon dioxide = reduced ( gains electron from Nadph)

Question 6

Why do plants need glucose

Answer 6

1. To generate ATP
2. nourish non-photosynthetic parts of the plant.
3. Produce cellulose
4. other biochemicals

Question 7

Most plants store Excess glucose as

Answer 7

1. Starch

2. Sucrose

Question 8

Explain the evolution of Photosynthesis

Answer 8

Before photosynthesis evolved, organisms were heterotrophs that relied on organic molecules as a carbon source.

The first autotrophs developed the ability to produce their own organic molecules from atmospheric Co2.

Oxygen produced by these organism changed the Earth’s climate

Question 9

Visible Light

Answer 9

A small part of the Electromagnetic Spectrum

Question 10

Photons

Answer 10

Packets of energy that move in waves.

Question 11

Effect of wave length and kinetic energy

Answer 11

The longer the wavelength the less kinetic energy per photon

Question 12

Photosynthetic pigments do what

Answer 12

Capture Light Energy

Question 13

2 types of pigments found in chloroplasts

Answer 13

1. Chlorophyll a

2. accessory Pigments

Question 14

Chlorophyl a

Answer 14

The primary photosynthetic pigment– Reaction Center ( along with proteins)

Question 15

Accessory pigment

Answer 15

absorb wavelengths of light that chlorophyll a cannot absorb, extending the range of wavelengths useful for P/S

Question 16

Chloroplasts are

Answer 16

The sites of P/S

Question 17

Stomata

Answer 17

Pores where plant exchange gases with the environment through ( take in co2 and release O2)

Question 18

Mesophyll

Answer 18

collective term for the internal cells of the plant.

Question 19

Stroma

Answer 19

gelatinous matrix in the chloroplast ( outside the thylakoid membrane.

Question 20

Thylakoid membrane

Answer 20

Site of light reaction. assembled in stacks in the the stroma.

Question 21

Grana ( granum singl. )

Answer 21

Stacks of thylakoid membrane

Question 22

Where are the pigments embedded

Answer 22

In the Thylakoid membrane

Question 23

Photosystem

Answer 23

Consists of:

1. Antenna Pigments
2. Reaction Center ( chlorophyll a)

Question 24

2 stages of P/S

Answer 24

1st. Light Reaction ( light dependent)

2nd. Carbon Reaction ( Light independent)

Question 25

The 2 main products of Light Reaction needed by the 2nd stage

Answer 25

1. ATP

2. NADPH

Question 26

The use of ATP and NADPH for Carbon Reaction

Answer 26

They provide energy and electrons for the glucose producing carbon reaction

Question 27

Photosystem II produces

Answer 27

ATP

Question 28

Photosystem ! Produces

Answer 28

NADPH

Question 29

THE 2 STAGES OF LIght Reaction

Answer 29

Photosystem I

Photosystem II

Question 30

Steps of Photosystem I

Answer 30

1. Antenna pigments capture photons from light energy.
2. Sends it to the Reaction center ( chlorophyll a)
3. chlorophyll a releases an electron into an Electron Transport Chain that joins Photosystem I with Photosystem II
4. Electrons from chlorophyll a are replaced by splitting water. O2 is a waste product.
5. Energy released in the ETC drives the active transport of protons ( through a proton pump) from the stroma into the thylakoid space.
6. Accumulation of protons from water splitting and active transport creates a transport gradient.
7. The protons diffuse in ATP Synthase
8. Th movement powers the phosphorylation of ADP to ATP

Question 31

Chemiosmotic Phosphorylation

Answer 31

The coupling of the

1. proton gradient
2. ATP formation

Question 32

Steps of Photosystem I

Answer 32

P/s I receives electrons from the electron transport chain

2. The electrons are used to reduce NADP to NADPH ( NADP + H)
3. Light is captured again to power this process

Question 33

Carbon Reaction produces

Answer 33

carbohydrates

Question 34

How does Carbon reaction produce carbohydrates

Answer 34

The carbon reactions use energy from ATP and electrons from NADPH in carbon fixation reactions that incorporate Co2 into organic molecules.

Question 35

Carbon fixation

Answer 35

reactions that incorporate Co2 into organic compounds. The first of Carbon Reaction

Question 36

3 names for the 2nd stage of P/S

Answer 36

1. Carbon Reaction
2. Calvin cycle
3. C3 Pathway

Question 37

Steps of Carbon Reaction

Answer 37

1. Rubisco catalyzes the reaction of Co2 with RuBP to yield 2 molecules of PGA.
2. PGA Molecules are converted into PGAL
3. PGAL later becomes glucose

Question 38

PGAL

Answer 38

the immediate Carbohydrate of P/S which later becomes glucose.

Question 39

C3 Pathway

Answer 39

Another name for the Calvin Cycle.

Refers to plants that can only use this pathway to fix carbon ( to two 3 carbon molecules with one phosphate-PGA)

Question 40

3 pathways plants use to fix carbon

Answer 40

1. C3
2. C4
3. CAM

Question 41

Photorespiration

Answer 41

wastes carbon and energy when rubisco reacts with O2 instead of CO2

Question 42

How do C4 pathway plants reduce Photorespiration

Answer 42

By separating the light and carbon reactions into different cells
Light reaction in the Mesophyll cells and Carbon Reactions int the the bundle sheath cell

Question 43

How do CAM pathway plants reduce Photorespiration

Answer 43

Desert plants such as Cacti open their stomata and take in Co2 at night, storing fix carbon in vacuoles. during the day Light reactions occur

Question 44

Where does the energy come from to peer P/S

Answer 44

The Sun

Question 45

P/S is an example of an ——– chemical reaction because ———

Answer 45

Endergonic Reaction because light energy is used to build chemical bonds.