Bio Chap. 8 Photosynthesis

Front 1

What is an organism that self feeds vs. an organism that feeds upon others?

Back 1

Self feed = autotroph

Others = Heterotroph

Front 2

Stoma

Back 2

pores in a leaf that allow CO2 to enter and O2 to exit

Front 3

Mesophyll cells

Back 3

make up the ground tissue of the leaf

Front 4

Chloroplasts
What?
Where?
Structure?

Back 4

• Organelle where photosynthesis takes place
• found within the mesophyll cells
• has an inner and outer membrane

Front 5

Stroma

Back 5

gelatinous fluid in the chloroplasts where sugar is made

Front 6

Grana

Back 6

Stacks of thylakoid disks in the chloroplasts

Front 7

Thylakoid membrane

Back 7

The membrane of the grana in which the photosystems are embedded

Front 8

Thylakoid space

Back 8

space within the grana in which the H+ ion concentration gradient is built

Front 9

Pigments
What are they?
Where are they?
What do they do?
3 types

Back 9

• Pigments are photoreceptors for photosynthesis
• They are within the photosystems embedded within the thylakoid membrane
• They reflect, transmit and absorb light
• This is due to their varying structures

3 types:
1) Chlorophyll A
2) Chlorophyll B
3) Carotenoids

Front 10

What determines which wavelengths pigments will reflect, transmit, or absorb?

How do chlorophyll A and B differ?

Back 10

Their structure

Chlorophyll A and B differ by one functional group

Front 11

What are the interdependent functions of the chloroplasts and mitochondria?

Back 11

Chloroplasts make sugar
Mitochondrion break down sugar

Front 12

Photosynthesis equation

Back 12

6 CO2 + 6 H20 → C6H12O6 + 6 O2

Front 13

In photosynthesis, CO2 is oxidized/reduced to...?
H2O is oxidized/reduced to...?

Back 13

CO2 is reduced to sugar
H2O is oxidized into O2

Front 14

All the O2 that we inhale comes from ______ and gets turned back into ______ in our bodies.

Back 14

Water

Front 15

White light
4

Back 15

• electromagnetic energy or radiation
• travels in rhythmic waves
• represented by Greek letter lambda ƛ
• wavelengths are measured from crest to crest (trough to trough)

Front 16

Electromagnetic spectrum
2

Back 16

• Ranges from gamma rays to radio waves
• humans can only detect a fraction of the spectrum

Front 17

Photon
2

Relationship of energy of a wave to wavelength

Back 17

• A particle of light that acts as discrete bundle of a fixed amount of energy
• 1 color

• the energy of a wave is inversely proportional to its wavelength

Front 18

What are the 2 stages of photosynthesis and where do they occur?

Back 18

1) Light reaction occurs in the thylakoid membrane
2) Calvin Cycle occurs in the stroma

Front 19

What are the products of light reaction and what molecule are they made from?

Back 19

• ATP from ADP + P
• NADPH from reducing NADP+
• O2 from oxidizing H2O

Front 20

What is NADP+ ?

Back 20

The coenzyme involved in photosynthesis

Front 21

What is photophosphorylation?

Back 21

How ATP is made due to the chemiosmosis of photosynthesis

Front 22

Which pigment(s) directly participate in photosynthesis, and which indirectly participate?
What does this mean?

Back 22

Chlorophyll A directly participates
Chlorophyll B and carotenoids indirectly participate

1) Chlorophyll B and carotenoids capture light energy and bounce the energy between them until it reaches chlorophyll A
2) an excited e- from Chlorophyll A is passed along into the ETC and to photosystem I or reduce NADP+ to NADPH

Front 23

What are the 2 parts of a photosystem?
What occurs within them?

Back 23

A) Light Harvesting Complex
1) A photon hits a chlorophyll B or carotenoid pigment
2) The photon excites e- in the pigments and this excitation is passed from one pigment to another
3) When the energy is passed, the e- falls back to ground state in its pigment

B) Reaction Center:
1) The energy reaches the reaction center and excites an e- of a chlorophyll A molecule
2) The actual excited e- itself is passed along and reduces the primary e- acceptor (quinone in PS II)
3) The oxidized chlorophyll A molecule has its e- replenished by H2O, an e- donor
4) The oxidized H2O is split into 2 H+ ions and 1/2 O2

Front 24

What is the primary electron acceptor in photosystem II, and what is it reduced to?

Back 24

Quinone is reduced to plastoquinone

Front 25

What is the difference between photosystem I and photosystem II?
What accounts for this difference?
In what order do they occur?

Back 25

Photosystem I has an absorption peak of 700 nm
Photosystem II has an absorption peak of 680 nm

The difference is due to the different proteins in the membrane that the chlorophyll A's are associated with.

Photosystem II occurs BEFORE photosystem I

Front 26

What are the e- acceptors of the two ETCs in their order of occurrence?

Back 26

ETC 1:
1) plastoquinone
2) cytochrome (b6-f) complex
3) plastocyanine

ETC 2:
1) ferredoxin
2) NADP reductase: reduces NADP+ to NADPH

Front 27

What replenishes the electrons lost from each photosystem?

Back 27

e- of photosystem I are replenished by e- of photosystem II

e- of photosystem II are replenished by H2O

Front 28

What is made in each ETC?

Back 28

The first ETC, between the 2 photosystems, produces ATP

The second ETC, after photosystem I, produces NADPH

Front 29

What is the difference between non-cyclic and cyclic flow of electrons?

Back 29

Non-cyclic flow:
electrons travel both ETCs and end up in NADPH

Cyclic flow:
• electrons do not make it to NADP reductase
• after ferredoxin, e- cycle back to cytochrome complex

Front 30

What does the cyclic flow of electrons make happen?
Why does this occur?

Back 30

• the cyclic flow accelerates the pumping of H+ through cytochrome complex
• this accelerates chemiosmosis and photophosphorylation

This happens because:
• The Calvin Cycle uses more ATP than NADPH
• when ATP is almost used up, cyclic cycle flow begins

Front 31

From where to where does the cytochrome complex pump H+ ions?

What is built here?

Back 31

From the stroma to the thylakoid space there a proton concentration gradient is built

Front 32

_______________ is to chloroplasts as oxidative phosphorylation is to mitochondria.

Back 32

Photophosphorylation

Front 33

Where does the Calvin Cycle occur and why?

Back 33

In the stroma b/c this is where ATP is made from photophosphorylation

Front 34

What is the key process that occurs in the Calvin Cycle?
What is this process?
What molecules are needed for this to occur?
Is this exergonic or endergonic?

Back 34

Carbon fixation:
• CO2 bonds with an organic molecule which will eventually be reduced to sugar
• the ATP and NADPH that was made in the light rxns are needed
• endergonic

Front 35

What are the steps of the Calvin Cycle?

Back 35

1) CO2 bonds with ribulose 1,5-bisphosphate (RuBP)
2) The 6-carbon product splits into two 3-phosphoglycerate (3PG)
3) 3PG is phosphorylated by ATP into 1,3-bisphosphoglycerate
4) 1,3-bisphosphoglycerate looses a phosphate and is reduced by NADPH to form glyceraldehyde 3-phosphate (G3P)
5) some G3P is used to make glucose
6) 10 molecules of G3P are phosphorylated by ATP to regenerate RuBP

Front 36

What process in reverse makes glucose?

Back 36

Glycolysis

Front 37

What do plant cells use glucose for?

Back 37

1) build cellulose for the cell wall
2) build starch for storage
3) break it down in the mitochondria