Section 4: Photosynthesis Flashcards Preview

DAT Bio > Section 4: Photosynthesis > Flashcards

Flashcards in Section 4: Photosynthesis Deck (77):
1

What is the overall equation for photosynthesis?

6CO2 + 6H2O --> C6H12O6 + 6O2 (+6H2O)

2

Photosynthesis begins with light absorbing ____ in plant cells

They are able to absorb energy from _______

Pigments

light

3

What are the pigments involved in photosynthesis that absorb energy from light?

Chlorophyll a, b, and carotenoids (red orange, yellow)

4

In photosynthesis, light energy is incorporated into _____

Electrons

5

Excited electrons in photosynthesis re-emit absorbed energy, which is then reabsorbed by neighboring electrons of a nearby _____ molecule

Pigment

6

The photosynthesis process ends when energy is absorbed by one of two special ___________ molecules

What are these two molecules?

Chlorophyll a molecules

P680 and P700

7

This chlorophyll a molecule forms pigment cluster (PSI)

P700

8

This chlorophyll a molecule forms pigment cluster (PSII)

P680

9

This type of pigement capture wavelengths that chlorophyll a does not, and passes it on to chlorophyll a where the direct light reaction occurs

Antenna pigment

10

What are the antenna pigments?

Chlorophyll b, carotenoids, phycobilins (red algae pigment)

11

Chlorophyll a has a ______ ring, which is alternating double and single bonds, the double bonds are critical for light rxns

What is it complexed with?

Poryphin ring

Mg atom

12

What is the equation for photophosphorylation? AKA the light dependent reaction in photosynthesis

ADP + Pi + light => ATP

13

In this part of photophosphorylation, electrons are trapped by P680 in PSII are energized by light

Photosystem II

14

In photophosphorylation, two excited electrons are passed to a primary electron ______, primary because it is the first in a chain of them

Acceptor

15

The electron transport chain in photophosphorylation consists of ________ which contains proteins and a cofactor

Plastoquinone complex (PSII)

16

What is an example of a protein that plastoquinone complex (PSII) in photophosphorylation contains?

What cofactor does it contain?

Cytochrome

Fe2+

17

What is the electron transport chain analagous to in cellular respiration?

Oxidative Phosphorylation

18

In photophosphorylation, this phase moves 2 electrons down the primary acceptor chain

Does this cause the loss or gain of energy?

Phosphorylation

Loss of energy

19

How much energy does it cost to phosphorylate in photophosphorylation?

~1.5 ATP

20

In this part of photophosphorylation, the electron transport terminates with PSI (P700)

The electrons are again energized by ____ and passed on to another primary electron acceptor

From THIS point forward things can become cyclic or noncyclic

Photosystem I

sunlight

21

If noncyclic photophosphorylation, after photosystem I, 2 electrons pass down a short ETC with proteins like ferrodoxin to combine and create.....

NADPH (coenzyme)

NADP+ + H+ + 2e- => NADPH

22

In noncyclic photophosphorylation, after the formation of NADPH, the loss of electrons from the ____ initially is replaced with....

What does it form

PSII

H2O

2e-, 2H+ and 1/2O2

23

Where does noncyclic photophosphorylation take place in plants?

Thylakoid Membranes

24

How many photosystems in each thylakoid?

A few hundred

25

Where does cyclic photophosphorylation take place?

Stroma Lamellae (piece connecting the thylakoids)

26

Where does photolysis occur?

Thlaykoid lumen (passes e- to the membrane for noncyclic photophos)

27

Where does the calvin cycle take place?

Stroma

28

Where does chemiosmosis take place

Thylakoid Membrane

29

All of the aforementioned processes (photolysis, chemiosmosis, calvin cycle, photosystems, etc) take place inside of the

Chloroplast

30

What absorbs light in photosynthesis?

Thlyakoid membranes, NOT chloroplast membranes

31

This type of photophosphorylation replenishes ATP when the calvin cycle consumes it

When excited, 2 electrons from _____ join with protein carrier in the first ETC and generate how many ATP as they pass through?

They are then recycled into _____ and can take either the cyclic or noncyclic path

Cyclic photophosphorylation

PSI

1 ATP

PSI

32

The Calvin cycle fixes ______

It repeats this ____ times

It is used to produce

This is _____ photosynthesis

CO2

6 times (6CO2)

C6H12O6 (glucose)

C3 photosynthesis (dark reaction)

33

In this step of cyclic photophosphorylation, 6CO2 + 6RuBP => 12PGA

What catalyzes the reaction? It's the most common protein in the world!

Why is the calvin cycle called C3 photosynthesis?

Carboxylation

RuBisCo

PGA is 3C

34

After carboxylation, this step occurs with the reaction 12PGA => 12G3P

What 2 things do this conversion?

What are the by-products and where do they go?

Reduction

12ATP+12NADPH convert it

NADP+ and ADP

They go into noncyclic photophosphorylation

35

After reduction, in this step 6 ATP convert to 10G3P to 6RuBP, which allows the cycle to repeat

Regeneration

36

After regeneration, what happens to the 2 remaining G3P?

They are used to build glucose

6CO2 + 18ATP + 12NADPH + H+ => 18ADP + 18Pi + 12NADP+ + 1glucose (2G3P)

37

Can the "dark reaction" aka calcin cycle occur without light?

No. It is dependent upon high energy molecules produced from the light rxn (ATP and NADPH)

38

The energy stored in glucose during photosynthesis is in the form of chemical bonds, but the energy initially comes from

Light

39

Plants DO/DO NOT have mitochondria that make ATP

What is the important difference to remember, then?

They do have mitochondria that make ATP

ATP from photosynthesis comes from the chloroplast, not mitochondria

40

Where does the glucose that is made during photosynthesis go to be used as energy?

Mitochondria

41

Is photosynthesis ATP used for general cell fxn?

No. ?

42

This organelle is where light dependent and light independent reactions occur

Chloroplast

43

Does the chloroplast have a double membrane like the mitochondria and nucleus?

Yes

44

What are the three components of the double membrane in the chloroplast?

Outer membrane (phospholipid bilayer/plasma membrane)

Intermembrane space

Inner Membrane (phospholipid bilayer/plasma membrane)

45

This is the fluid material that fills inside the inner membrane of the chloroplast

What occurs here?

Stroma

The Calvin Cycle (fixing Co2=>G3P)

46

These are suspended within stroma (stacks), and are individual membrane layers

What is an entire stack of them called?

Thylakoids

Granum

47

What does the membrane of thylakoids contain?

Are thylakoids a phospholipid bilayer?

PSI and PSII, cytochromes, and other e- carriers.

Yes.

48

This is the interior of the thylakoid

What accumulates here?

Thylakoid Lumen

H+

49

Gradient uses ________ to move the accumulated H+ from thylakoid lumen to _______

H+ moves in to out to generate _______ via the synthase

How is this different than oxidative phosphorylation?

ATP synthase

Stroma

ATP

H+ builds up outside and is shuttled INTO the mitochondria to generate ATP via synthase

50

In chloroplasts, this is the term for using H+ gradient to generate ATP

Chemiosmosis

51

What accumulates inside of thylakoids during chemiosmosis?

Where are they released when H2O is split by PSII?

It is also carriend into lumen from stroma by ____ between PSIII and PSI

H+ ions

Lumen

cytochrome

52

What type of gradient is created during chemiosmosis?

A pH and electrical gradient

53

What is the pH of the gradient during chemiosmosis?

pH 5

54

What generates ATP during chemiosmosis?

ATP synthase

phosphorylate ADP + Pi => ATP. (3H+ is required for 1ATP

55

The Calvin cycle produce _________ using NADPH and CO2 and ATP

At the end of the ETC following PSI, 2 electrons produce

2 G3P

NADPH

56

This is the fixation of oxygen by rubisco (can also fix CO2) => produces no ATP or sugar

Photorespiration

57

Is photorespiration efficient?

No,rubisco will fix both CO2 and oxygen at the same time if both are present. Probably arose because early earth
atmosphere didn’t have much O2 so it didn’t matter. Peroxisomes breakdown the products of this process

58

This type of photosynthesis occurs when CO2 enters a leaf, it is absorbed by mesophyll cells instead of being fixed by rubisco into PGA

CO2 combines with PEP to form ____ by PEP carboxylase in the mesophyll

C4 Photosynthesis

OAA

59

Why is it called C4 synthesis?

OAA has 4C

60

What does OAA become in C4 photosynthesis?

Where is it transported to via plasmodesmata?

Malate

Bundle Sheath Cell

61

What is malate converted to in C4 photosynthesis?

Pyruvate + CO2

62

When malate is converted to pyruvate and CO2 in C4 photosynthesis, where does each go?

CO2 is used in Calvin cycle

pyruvate is moved back to the mesophyll

63

The overall purpose of C4 photosynthesis is to move CO2 from the mesophyll to the

Bundle Sheath Cell

64

This is the structure of C4 photosynthesis

This is the process of C4 photosynthesis

Kranz anatomy

Hatch-Slack pathway

65

Where is C4 photosynthesis found?

It requires 1 additional _____ which becomes ____

Hot, dry climates (faster fixation speed and more efficient)

ATP, AMP

66

C3 typically occurs in ____ cells

C4 typically occurs in _____ cells

mesophyll cells

Bundle Sheath cells

67

This is another thing that evolved from C3, it is almost identical to C4. It comprises CRASSULEACEAN ACID METABOLISM

CAM photosynthesis

68

In CAM photosynthesis, PEP carboxylase fixes CO2 + PEP to

This product is converted to

OAA

Malic Acid

69

Where is malic acid shuttled to in CAM photosynthesis?

Vacuole of cell

70

In CAM photosynthesis, at night, stomato are ______ which is the opposite of normal

What is active?

So what accumulates in the vacuole?

Open

PEP carboxylase

Malic Acid

71

In CAM photosynthesis, during the day, stomata are ____ (opposite of normal)

Where is malic acid?

What is it converted to?

What does this release?

Closed

Out of the vacuole

Back to OAA (requires 1 ATP)

CO2 and PEP

72

Where does the CO2 go that is produced during CAM photosynthesis?

Calvin cycle with rubisco

73

The advantage of CAM photosynthesis is that it can...

Proceed during day while stomata are closed (reduces H2O loss)

74

As leaves age, chlorophyll breaks down to extract valuable components like Mg2+, ______are visible.

carotenoids

75

The calvin cycle occurs in the ___ of chloroplast

Stroma

76

The splitting of H2O provides ___ for noncyclic photophosphorylation

Where is it incorporated?

2e-

NADPH and calvin cycle

77

Is the calvin cycle dependent upon light?

No, but ATP and NADPH are produced from a light dependent reaction