Ch. 7 Photosynthesis: Using Light to Make Food Flashcards Preview

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Flashcards in Ch. 7 Photosynthesis: Using Light to Make Food Deck (48):
1

Photosynthesis

Putting together glucose with light.
- light energy ---> chemical energy (Energy Transaction)

2

What is the equation for photosynthesis?

6CO2 + 6H2O --- Light Energy ---> C6H12O6 + 6O2

3

Autotrophs

An organism that makes its own food
- 2 methods: photosynthesis, and chemiosmosis

4

Producers

An organism that makes organic food molecules from CO2, H2O, and other inorganic raw materials

5

Where does photosynthesis occur?

All green parts of the plant. Leaves particularly. It is particularly the membranes of chloroplast.

6

Mesophyll

The green tissue in the interior of a leaf
- numerous chloroplast
- main site of photosynthesis

7

Stomata

A pore surrounded by guard cells in the epidermis of a lead
- CO2 enters, water and O2 exit

8

Stroma

Thick fluid where sugars are made by enzymes of the Calvin Cycle

9

Thylakoids

Disc shaped membranous sacs inside a chloroplast that contains chlorophyll and the enzymes of the light reactions of photosynthesis

10

Grana

A stack of hollow discs formed of thylakoid membrane in the chloroplast
- site where light energy is trapped by chlorophyll and converted to chemical energy during light reactions of photosynthesis

11

What is reduced and oxidized in photosynthesis?

CO2 is reduced. H2O is oxidized.

12

Light Reactions

The first of two stages in photosynthesis. Steps in which solar energy is absorbed and converted to chemical energy in the form of ATP and NADPH.
- powers the sugar producing Calvin Cycle

13

Calvin Cycle

The second of two stages of photosynthesis. A cyclic series of chemical reactions that occur in the stroma of a chloroplast using the carbon in CO2 and the ATP/NADPH produced in light reactions to make energy rich sugar molecule G3P

14

Carbon Fixation

Carbon from the air combines with RuBP to make 3 C6 which is unstable and turns into PGA

15

Electromagnetic Energy

Solar energy or radiation which travels in space as rhythmic waves and can be measured in photons

16

Wavelength

The distance between crests of adjacent waves

17

What wavelengths do carotenoids absorb?

Yellow-orange pigments

18

What color is least effective in driving photosynthesis?

Green

19

Photon

Fixed quantity of light energy
- shorter the wavelength, greater the energy

20

Reaction Center

In a photosystem in chloroplast, the chlorophyll "a" molecule and the primary electron acceptor that trigger the light reactions of photosynthesis
- absorbed energized light energy (electrons)

21

Photosystem

Light harvesting unit of a chloroplast's thylakoid membrane
- consists of several hundred antenna molecules, a reaction center chlorophyll, and a primary electron acceptor

22

What are the three key events of light reactions?

1) Absorption of light energy
2) Excitation of electrons by that energy
3) Formation of ATP and NADPH using energy made available by electrons

23

Photophosphorylation

The production of ATP by chemiosmosis during the light reactions of photosynthesis

24

What are the 2 stages of photosynthesis?

1) Light Reactions
2) Calvin Cycle

25

What 3 things do all cells use?

1) Electron Transport
2) Redox reactions
3) Chemiosmosis

26

C3 Plants

Plants where Calvin Cycle uses CO2 directly from the air
- common, widely distributed
- stomata closes in dry air

27

Photorespiration

In a plant cell, the breakdown of a 2C produced by Calvin Cycle instead of G3P w/ 3C when leaf cell fixes O2 instead of CO2

28

C4 Plants

Plants have special water adaptations and prevent photorespiration

29

CAM Plants

Plants adapted to very dry climates
- conserves CO2 by opening stomata at night

30

Old Growth Forest

An ancient forest that has never been seriously disturbed by humans
- trees dominating may be thousands of years old

31

Greenhouse Effect

Warming of the atmosphere caused by CO2, CH4, and other gases which absorb infared radiation and slow its escape from Earth's surface

32

Why is photosynthesis crucial to life?

It produces most of the oxygen in the atmosphere. Makes glucose for cell respiration (energy) and to build more complex molecules.

33

What do plants, some protists, and some bacteria all have in common?

All have chlorophyll that enables photosynthesis. [chloroplast is only an organelle by chlorophyll is what does the work specifically]

34

What are the parts of a leaf?

Cuticle, Upper epidermis, Palisade layer, Spongy layer, vein stomate (pore/guard cells), lower epidermis

35

Electromagnetic Spectrum

Full range of electromagnetic wavelength
- nanometers

36

What comprises the electromagnetic spectrum?

Gamma rays, x-rays, UV rays, visible light, infared, microwaves, radio waves

37

What are three things that can happen when an electron is excited?

Light. Heat. Down electron transport chain.

38

What are the three components of a photosystem?

1) 200 - 300 pigment molecules of chlorophyll (antenna)
2) Reaction center molecule
3) Primary Electron Acceptor

39

What is noncyclic photophosphorylation?

Adding phosphate to ATP using light

40

Photosystem I

Chlorophyll molecule with reaction center P700 where light is absorbed most strongly and electrons sent to NADP to make NADPH

41

Photosystem II

Identical to photosystem I but with P680 and electrons go to P700

42

What are the 3 events of light reactions?

1) Absorption of light by chlorophyll
2) Excitation of electrons caused by light
3) Splitting of water into hydrogen and oxygen (released to atmosphere) [Produces ATP/NADPH]

43

What are the five steps of light reactions?

1) Antenna pigments of photosystem I chlorophyll absorb light energy
2) Energized electrons sent to reaction center P700
3) Reaction center sends energized electrons to primary electron center
4) Primary electron acceptor is oxidized as it loses electrons (redox reactions)
5) Electrons arrive at NADP to make NADPH

44

What is the function of Photosystem II?

To split water into O2 and 4H+ to send electrons to P680 so electrons sent to an acceptor then to P700 to fill a void

45

What are the four steps of calvin cycle?

1) Carbon fixation
2) Energy consumption redox
3) Release of 1 molecule of G3P
4) Regeneration of RuBP

46

What are three key substances of calvin cycle?

PGA --> G3P --> RuBP

47

What do plants use sugar made in cell respiration for?

Make energy and building material. Excess is stored as starch.

48

Why is photosynthesis the ultimate source of food?

Produces oxygen, building material, and energy/fuel.