Ap Bio Chapter 10

Front 1

• Water is ___ CO2 is ___ in photosynthesis

Back 1

oxidized

reduced

Front 2

• Goal of light reactions

Back 2

use sunlight to make ATP and NADPH

convert solar energy to chemical energy

Front 3

• Goal of Calvin Cycles

Back 3

make sugars from ATP and NADPH

Front 4

• Calvin cycle must spin __ times to make __ glucose

Back 4

6

1

Front 5

• Calvin cycle must spin __ times to make __ PGAL (2 PGAL=1 glucose)

Back 5

3

1

Front 6

• Autotrophs

Back 6

sustain themselves without eating anything derived from other organisms- produce organic compounds from inhaling CO2- ultimate sources of organic compounds for non-autotrophic organisms
o Aka producers
o Plants are autotrophs

Front 7

• Photoautotrophs

Back 7

specifically plants
o Organisms that use light as a source of energy to synthesize organic substances

Front 8

• Heterotrophs

Back 8

obtain organic material by eating other things
o Aka consumers
o Can’t make their own food

Front 9

• Chlorophyll

Back 9

pigment that gives plants a green color
o Located in chloroplasts
o Found in mesophyll of chloroplast (tissue in the interior of the leaf)

Front 10

• Stomata

Back 10

microscopic pores in leaves- facilitates exchange of gasses like O2 and CO2

Front 11

• Stroma

Back 11

dense fluid within the chloroplast

Front 12

• Thylakoids

Back 12

membranous sacs within a chloroplast- separates stroma from thylakoid space→ holds chlorophyll in Thylakoid membrane

Front 13

• Granum

Back 13

-→ a stack of thylakoid membranes

Front 14

Photosynthesis equation

Back 14

• 6CO2 + 6 H2O + Light→ C6H12O6 + 6O2

Front 15

• Chloroplasts split ___ into ____

Back 15

water

hydrogen and oxygen

Front 16

• Light reaction

Back 16

o Convert solar energy to chemical energy
o Light absorbed by chlorophyll drives a transfer of electrons and hydrogen from water to NADP+
o Water is split
o Light reaction gives off O2 as a by product
o Electron acceptor in light reactions= NADP+
• NADP+ becomes NADPH when light energy adds 2 electrons and a H+ ion
o Light reaction generates ATP through chemiosmosis (photophosphorylation)
o Light energy gets converted to 2 things→ ATP or NADPH

Front 17

• Calvin cycle

Back 17

o Takes NADPH CO2 and ATP and makes sugar
o Carbon fixation→ initial incorporation of carbon into organic compounds
o Calvin cycle begins by incorporating CO2 from the air into organic molecules already present in the chloroplast
o CC reduces the fixed carbon to carbohydrate by adding electrons (through NADPH)
o CC does not directly require light
• Rely on NADPH and ATP from the light reactions

Front 18

• Light reaction happens in

Back 18

thylakoids

Front 19

• Calvin cycle happens in

Back 19

stroma

Front 20

o Wavelength

Back 20

distance between crests of electromagnetic waves

Front 21

o Electromagnetic spectrum

Back 21

GXUVIMR

Gamma- short wavelength high energy

Radio- long wavelength low energy

Front 22

visible light spectrum

Back 22

ROYGBIV

Red- long wavelength low energy

Violet- short wavelength high energy

Front 23

photons

Back 23

o Light behaves as though it consists of discrete particles called photons
• Each photon has a fixed quantity of energy

Front 24

• When light hits matter it is either...

Back 24

reflected transmitted or absorbed

Front 25

• Pigments

Back 25

substances that absorb visible light
o The color you see is the color reflected back- the color it doesn’t absorb
o If it absorbs all wavelengths the color is black

Front 26

• Spectrophotometer

Back 26

measures the ability of a pigment to absorb various wavelengths of light

Front 27

• Chlorophyll a

Back 27

absorbs violet and blue, reflects blue and green

Front 28

• Chlorophyll b

Back 28

absorbs violet and blue, reflects yellow and green
o Almost the same as chlorophyll A but slightly structurally different

Front 29

• Carotenoids

Back 29

reflect yellow orange and red - absorb violet blue and green

o In the fall, plants stop making chlorophyll and all you have left are the carotenoids

Front 30

o Photoprotection

Back 30

carotenoids absorb and dissipate excessive light energy that would otherwise damage chlorophyll or interact with oxygen

Front 31

Excitation of chlorophyll by light

Back 31

• Ground state→ electron is in its normal orbital
• Absorption of a photon boosts an electron to an orbital of higher energy (excited state)
o The photons absorbed are those whose energy is exactly equal to the energy difference between the ground and excited state
• When the electrons drop back down from the excited to the ground state they release energy (in the form of heat and sometimes light)

Front 32

o Fluorescence

Back 32

the afterglow from when after the electrons fall back down and release heat/light

o Isolated Chlorophyll will fluoresce and give off heat because it's not in a chloroplast and there's no electron acceptor to harness the energy

Front 33

• Photosytem

Back 33

reaction center associated with light harvesting complexes
o Composed of a reaction center surrounded by a number of light harvesting complexes

Front 34

• Light harvesting complex

Back 34

consists of pigment molecules (chlorophyll a or b or carotenoids)
o Number and variety of pigment molecules enable a photosystem to harvest light over a larger surface and larger portion of the spectrum

Front 35

• Reaction center

Back 35

protein complex that includes two chlorophyll a molecules and a primary electron acceptor
o Light hits Chlorophyll a and it transfers an electron to the primary electron acceptor (first step of light reactions)
• Electron jumps up and gets caught by the primary electron acceptor

Front 36

• 2 kinds of photosystems-→

Back 36

Photosystem II and photosystem I
o both have a reaction center, primary electron acceptor, chlorophyll a molecules,

2 comes before 1

Front 37

• Noncyclic electron flow

Back 37

o The usual electron route through the light reactions
o Makes NADPH and ATP
o Pushes electrons from water (low state of potential energy) to NADPH (high state of potential energy)

Front 38

• Cyclic electron flow

Back 38

second path of electron flow through the light reactions
o Uses PS I and not PS II
o Only makes ATP (no NADPH)
o Since the calvin cycle consumes more ATP than NADPH cyclic electron flow helps power the calvin
o Concentration of NADPH in the chloroplast could help regulate which pathway (cyclic or non cyclic) the electrons travel through

Front 39

differences between mitochondria oxidative phosphorylation and chloroplast photophosphorylation

Back 39

• Oxidative phosphorylation→ mitochondria
o Electrons are extracted from organic molecules
o Transfers chemical energy to ATP
o Inner membrane pumps protons from matrix to intermembrane space


• Photophosphorylation→ chloroplasts
o Use light to drive electrons down the chain
o Transfers light energy to ATP and NADPH
o Thylakoid membrane pumps protons from stroma to thylakoid space
o Thylakoid membrane makes ATP
o ATP forms in stroma

Front 40

• Calvin cycle is ___

Back 40

anabolic (builds sugar from smaller low energy molecules- consumes energy)

Front 41

photorespiration

Back 41

o Plants perform photorespiration when CO2 levels are low (when the stomata are closed when it's dry outside)

occurs in light, consumes O2, produces CO2
o Consumes rather than generates ATP
o Doesn’t produce sugar
o Decreases photosynthetic output
o Very counterproductive process

Front 42

transpiration

Back 42

o Water moves through the stomata
• When it’s dry outside the plant loses water (transpiration)
• Transpiration→ evaporation of water from leaves

Front 43

• C3 plants

Back 43

o Rice, wheat, soybeans
o Initial fixation of carbon occurs via Rubisco
o First organic product of carbon fixation is 3 phosphoglycerate
o Rubisco binds to either O2 or CO2
o When Rubisco binds to O2 the plant photorespires

Front 44

• C4 plants

Back 44

o Sugarcane, corn, grasses
o Two distinct types of photosynthetic cells
• Bundle sheath cells
• Arranged into tightly packed sheaths around the veins of the leaf
• Calvin cycle happens here
• Mesophyll cells
• Carbon fixation happens here
o Pep carboxylase→ fixes the carbon
• Higher affinity for CO2 and no affinity for O2
• More efficient than rubisco
o Mesophyll cells in C4 plants pump CO2 into the bundle sheath
• Keeps CO2 concentrations high so the rubisco can bind to CO2 and not O2
o C4 photosynthesis minimizes photorespiration and enhances sugar production
• Advantageous in hot dry regions
o Calvin cycle occurs in bundle sheath and carbon fixation occurs in mesophyll

Front 45

• CAM plants

Back 45

o Cactus, pineapples, jade plants
o Open stomata at night when it’s not as hot out
• Helps them to conserve water
o CAM= crassulacean acid metabolism
o Preform the light reactions during the day and the calvin cycle at night
o Calvin cycle and carbon fixation occur in the same cell

Front 46

• Plants make more organic material each day than they need so_____

Back 46

they store extra sugar in the form of starch