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Flashcards in Photosynthesis Chapter 5 Summary Deck (45)
1

Photosynthesis

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

2

Photosynthetic organisms

1.Plants
2. Algae
3. Some microorganisms

3

Photosynthesis builds what from what

Builds carbohydrates from carbon dioxide and water

4

What type of reaction is P/S

Redox

5

REdox reaction of P/S

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

6

Why do plants need glucose

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

7

Most plants store Excess glucose as

1. Starch
2. Sucrose

8

Explain the evolution of Photosynthesis

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

9

Visible Light

A small part of the Electromagnetic Spectrum

10

Photons

Packets of energy that move in waves.

11

Effect of wave length and kinetic energy

The longer the wavelength the less kinetic energy per photon

12

Photosynthetic pigments do what

Capture Light Energy

13

2 types of pigments found in chloroplasts

1. Chlorophyll a
2. accessory Pigments

14

Chlorophyl a

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

15

Accessory pigment

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

16

Chloroplasts are

The sites of P/S

17

Stomata

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

18

Mesophyll

collective term for the internal cells of the plant.

19

Stroma

gelatinous matrix in the chloroplast ( outside the thylakoid membrane.

20

Thylakoid membrane

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

21

Grana ( granum singl. )

Stacks of thylakoid membrane

22

Where are the pigments embedded

In the Thylakoid membrane

23

Photosystem

Consists of:
1. Antenna Pigments
2. Reaction Center ( chlorophyll a)

24

2 stages of P/S

1st. Light Reaction ( light dependent)
2nd. Carbon Reaction ( Light independent)

25

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

1. ATP
2. NADPH

26

The use of ATP and NADPH for Carbon Reaction

They provide energy and electrons for the glucose producing carbon reaction

27

Photosystem II produces

ATP

28

Photosystem ! Produces

NADPH

29

THE 2 STAGES OF LIght Reaction

Photosystem I
Photosystem II

30

Steps of Photosystem I

1. Antenna pigments capture photons from light energy.
2. Sends it to the Reaction center ( chlorophyll a)

2. chlorophyll a releases an electron into an Electron Transport Chain that joins Photosystem I with Photosystem II

3.Electrons from chlorophyll a are replaced by splitting water. O2 is a waste product.

4. Energy released in the ETC drives the active transport of protons ( through a proton pump) from the stroma into the thylakoid space.

5. Accumulation of protons from water splitting and active transport creates a transport gradient.

6.The protons diffuse in ATP Synthase

7. Th movement powers the phosphorylation of ADP to ATP

31

Chemiosmotic Phosphorylation

The coupling of the
1. proton gradient
2. ATP formation

32

Steps of Photosystem I

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

33

Carbon Reaction produces

carbohydrates

34

How does Carbon reaction produce carbohydrates

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

35

Carbon fixation

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

36

3 names for the 2nd stage of P/S

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

37

Steps of Carbon Reaction

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

38

PGAL

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

39

C3 Pathway

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)

40

3 pathways plants use to fix carbon

1. C3
2. C4
3. CAM

41

Photorespiration

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

42

How do C4 pathway plants reduce Photorespiration

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

43

How do CAM pathway plants reduce Photorespiration

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

44

Where does the energy come from to peer P/S

The Sun

45

P/S is an example of an -------- chemical reaction because ---------

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