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AP Bio > Unit 3: Cellular Energetics > Flashcards

Unit 3: Cellular Energetics Flashcards

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1
Q

Metabolism

A

ALL CHEMICAL RXNS: Totality of an organism’s chemical rxns
Manage materials & Energy resources of a cell
EX: apoptosis, growing hair, being awake/alive, digestion

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2
Q

Metabolism RXNs

A

A (start molecule) -> RXN 1 (enzyme A) -> RXN 2 (enzyme B) -> RXN 3 (enzyme C) -> D (product)
Each RXN has own enzyme w/ diff shapes for diff functions
Enzymes dont get used up in RXN js help facilitate them

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3
Q

Catabolic Pathway

A

Release Energy by BREAKING down
complex molecules into simpler compounds (gain energy)
Ex: digestive enzymes break down food -> release Energy, Hydrolysis, weightloss pills

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4
Q

Anabolic Pathway

A

CONSUME Energy to BUILD complex
molecules from simpler ones
Ex: amino acids link to form muscle protein, Dehydration synthesis, Steroids

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5
Q

Energy

A

Capacity to DO WORK

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6
Q

Kinetic Energy

A

Movement, Energy associated w/ Motion
Ex: HEAT (thermal energy) is KE associated w/ random movement of atoms or molecules (how fast molecules are moving)

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7
Q

Potential Energy

A

Position-based ex: Someone at top of Building, STORED energy as a result of its position/ structure
Ex: Chemical energy is PE available for release

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8
Q

Energy can be…

A

ONLY converted from 1 form to another (Never created/destroyed)
Ex: chemical -> mechanical -> electrical (forms of PE)

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9
Q

Thermodynamics

A

Study of Energy Transformations that occur in matter

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10
Q

Closed System

A

Isolated from its surroundings
(ex: liquid in a thermos)

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11
Q

Open System

A

Energy & Matter can be TRANSFERRED between system & surrounding
Ex: organisms

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12
Q

1st Law of Thermodynamics (Conservation of E)

A

Energy of Universe = Constant
E CANT be created or destroyed only transformed/transferred

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13
Q

2nd Law of Thermodynamics

A

Every E transfer/transformation, increase Entropy (disorder) of universe
During every E transfer/ transformation, some
E is unusable, often LOST as HEAT

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14
Q

Free Energy

A

Part of system’s E available to perform work
ΔG = change in free energy

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15
Q

Exergonic RXN

A

Energy is RELEASED
Spontaneous RXN
ΔG < 0
Hydrolysis/Catabolic

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16
Q

Endergonic RXN

A

Energy is REQUIRED
Absorb Free energy
ΔG > 0
Dehydration Synthesis/Anabolic

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17
Q

Is a living cell at Equilibrium?

A

NO, constant flow of materials in/out of cell

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18
Q

What 3 types of WORK do cells do?

A

Mechanical, Transport, Chemical

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19
Q

What is coupling?

A

Cells MANAGE Energy resources to do WORK by Energy coupling
Using an Exergonic process (up) to drive an Endergonic one (Rollercoaster)

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20
Q

ATP

A

(Adenosine TriPhosphate)
Cell’s MAIN Energy source in Energy Coupling
Adenine + ribosomes + 3 phosphates (Ex: Nucleic Acids)

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21
Q

How does pH affect enzymes?

A

Changing the pH outside of this range will slow enzyme activity. Extreme pH values can cause enzymes to denature.

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22
Q

How does temperature affect enzymes?

A

Raising temperature generally speeds up a reaction, and lowering temperature slows down a reaction
Extreme high temperatures can cause an enzyme to lose its shape (denature) and stop working

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23
Q

How does Hydrolysis affect bonds between phosphate groups of ATP?

A

When the bonds between the phosphate groups are broken by hydrolysis → Energy is released

*Release of E comes from Chemical Change to State of Lower Free E, NOT in the Phosphate Bonds themselves

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24
Q

How ATP Preforms WORK

A

Exergonic release of Pi is used to do the Endergonic work of cell
When ATP is hydrolyzed, it becomes ADP (adenosine diphosphate)

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25
Q

Transport Work

A

ATP phosphorylates Transport Proteins

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26
Q

Mechanical Work

A

ATP Binds non-covalently to motor proteins & then is HYDROLYZED -> Pi + ADP (walking protein)

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27
Q

Catalyst

A

Substance that can change Rate of a RXN W/OUT being altered in the process (by lowering activation energy)
ex: Enzyme = biological catalyst

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28
Q

Example of Catalyst

A

Sucrase BREAKS apart Sucrose enzyme, hydrolysis)
Speeds up Metabolic RXN by lowering activation Energy (needed to start RXN by breaking bonds)
W/O Enzyme = slower & less efficient

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29
Q

Substrate Specificity of Enzymes

A

The reactant that an Enzyme acts on is called the enzyme’s substrate
The enzyme binds to its substrate, forming an enzyme-substrate complex

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30
Q

Active site of Enzyme

A

Region on Enzyme where
substrate binds

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31
Q

Cycle of Enzyme

A

1) Substrates enters Enzyme’s Active site
2) Substrates held in Active Site by weak interactions
3) Substrates -> converted to products
4) Products are released
5) Active site available for new substrates

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32
Q

Induced Fit

A

Enzyme fits SNUGLY AROUND SUBSTRATE
“CLASPING HANDSHAKE”

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33
Q

Enzyme’s Activity can be Affected by?

A

Temperature, pH, Chemicals
bc Enzyme = protein & denatures sp ruins shape/function
Ex: stomach = low pH (acidic) so can digest stuff by enzymes

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34
Q

Cofactors

A

Nonprotein Enzyme helpers such as minerals (Ex: Zn, Fe, Cu) (bc body needs control)

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35
Q

Coenzymes

A

Organic Cofactors (ex: vitamins)

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36
Q

Enzyme Inhibitors

A

Competitive & Noncompetitive

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37
Q

Competitive Inhibitor

A

Binds to the Active Site of an
enzyme, competes w/ substrate (which will eventually win) & Enzyme will work again

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38
Q

Noncompetitive Inhibitor

A

Binds to Another part of Enzyme -> changes shape -> Active Site is Nonfunctional (SHUTS ENZYME DOWN FOREVER) bc substrate wont ever bump out noncompetitive (changes shape/function) Until enzyme destroyed

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39
Q

Regulation of Enzyme Activity

A

To regulate metabolic pathways, the cell switches on/off genes that encode specific enzymes

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40
Q

Allosteric Regulation

A

DIFF SHAPE REGULATOR
Protein’s Function at one site
is affected by binding of a regulatory molecule to a separate site (allosteric site)

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41
Q

Activator

A

Stabilizes Active Site

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42
Q

Inhibitor

A

Stabilizes Inactive form

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43
Q

Cooperativity

A

One substrate triggers shape change in other active sites → Increase catalytic activity

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44
Q

Feedback Inhibition

A

Series of Enzyme & RXN need to turn off/on certain things for balance
END PRODUCT of a Metabolic pathway shuts down Pathway by Binding to the Allosteric site of an enzyme
Prevent wasting chemical resources, increase efficiency
of cell
EX: make stomach pepsin & acid only when eating to digest food

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45
Q

Another Example of Feedback Inhibition

A

Threonine turns into isoleucine -> isoleucine shuts off threonine when enough bc wont have any more threonine (no waste) only makes more isoleucine when necessary no overproduction

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46
Q

How does chemicals denature enzymes?

A

competitive & noncompetitive inhibitors! MAINLY noncompetitive dont compete w/ substrate

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47
Q

In Open Systems, Plant Cells Require E to Preform Work (Chemical, Transport, Mechanical)

A

1) E flows into ecosystem as sunlight
2) Autotrophs (self, eat) transform it -> chemical E (O2 released as byproduct)
3) Cells use some of Chemical E in organic molecules to make ATP
4) Extra E LEAVES as HEAT

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48
Q
  • Complex Organic Molecules
A

Take Catabolic (break down) pathway to make simpler waste products w/ less E & some E used to do work & dissipated as HEAT

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49
Q

Cellular Respiration (Exergonic Releases E) - EQ:

A

C6H12O6(glucose) + 6O2(oxygen) → 6H2O(water) + 6CO2 (carbon dioxide)+ ATP (+ heat)

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50
Q

Photosynthesis (Endergonic, Requires/Absorbs E)

A

6H2O(water) + 6CO2(carbon dioxide) + Light (sun) → C6H12O6(glucose) + 6O2(oxygen)

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51
Q

***** Why is Oxygen important?

A

TERMINAL ELECTRON ACCEPTOR

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52
Q

Energy Harvest

A

Energy is released as electrons “fall” from organic molecules to O2
Steps: Food (Glucose) → NADH → ElectronTransportChain → Oxygen

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53
Q

Steps of Energy Harvest

A

1) Coenzyme NAD+ = electron acceptor
2) NAD+ picks up 2e- and 2H+ → NADH (stores E)
3) NADH carries electrons to the electron transport chain (ETC)
4) ETC: transfers e- to O2 to make H2O ; releases energy (ATP!!!)

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54
Q

NAD+ acts AS?

A

Electron Shuttle: energy from food, rips hydrogens & electrons from them

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55
Q

Electron Transport Chain (ETC)

A

Gains Free E from hydrogens (high in lipids = lots of calories)
Cellular Respiration: (Controlled steps) Slowly Releases Energy instead of explosion (uncontrolled) = staying alive

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56
Q

Stages of Cellular Respiration

A

1) Glycolysis
2) Pyruvate Oxidation + Citric Acid Cycle (Krebs cycle)
3) Oxidation Phosphorylation (Electron Transport Chain & Chemiosmosis)

57
Q

Glycolysis

A

AKA Fermentation
Glyco = Glucose, Lys = break
(but glucose doesnt break stuff)

58
Q

Oxidative Phosphorylation

A

oxidizing stuff but using Hydrogen to tell phosphores to rejoin party
etc + chemiosmosis
MAKES WAY MORE ATP

59
Q

Glycolysis

A

“Sugar Splitting”
Believed to be Ancient (early prokaryotes - no
O2 available)
Occurs in cytosol (no O2 before photosynthesis)
Partially oxidizes glucose (6Carbons) TO GET 2 pyruvates (3Carbons)
Net gain: 2 ATP + 2NADH (electron carrier) +2H+
Also makes 2 H2O water
NO O2 required

2 Stages: Energy Investment Stage, Energy Payoff Stage
produces 2 pyruvates for pyruvate oxidation

60
Q

Energy Payoff Stage

A

Two 3-Carbon compounds oxidized
For each glucose molecule:
2 Net ATP produced by substrate-level phosphorylation
2 molecules of NAD+ →NADH (electron carriers)
ADDS Phosphores by threatening (no energy needed)

61
Q

Substrate-Level Phosphorylation

A

Generate SMALL amount of ATP
Phosphorylation: enzyme transfers a phosphate to other compounds P+ compound (inorganic)
ADP + Pi (inorganic phosphate) → ATP
GETS 2 ATP

62
Q

Energy Investment Stage

A

Part 1 Of Glycolysis
Cell uses ATP to phosphorylate compounds of glucose

63
Q

Inputs & Outputs of Glycolysis

A

(Energy Investment) ATP -> phosphorylate glucose
(Energy Payoff) Inputs: 2 NAD+ -> Output: 2NADH & 2H+ & 2H2O
(Substrate level Phosphorylation)
Inputs: ADP + Pi -> Output: 2 ATP

Glucose(6-C) -> 2 Pyruvates (3-C)

64
Q

What are protons referring to?

A

H+ ions

65
Q

Stage 2: Pyruvate Oxidation

A

Pyruvate from glycolysis → Acetyl CoA (used to make citrate + Co2
CO2 & NADH produced
occurs in mitochondria cristae, cytosol -> cristae

66
Q

Inputs & Outputs of Pyruvate Oxidation

A

Inputs: NAD+ -> Output: NADH & CO2
Input: Pyruvate -> Acetyl CoA (makes citrate)

67
Q

Citric Acid Cycle (Krebs)

A

Occurs in mitochondrial matrix from pyruvate: 2 Acetyl CoA → 2 Citrate → 6 Co2 released
Net gain: 2 ATP, 8 NADH, 2 FADH2, 6CO2 (electron carrier NADH more efficient than FADH)
ATP produced by substrate-level phosphorylation

68
Q

Inputs & Outputs of Citric Acid Cycle (krebs)

A

Inputs: 2 pyruvate -> 2 Acetyl CoA + 2 ocoxaloacetate (forms citrate)
Outputs: 2 ATP, 8 NADH, 6CO2, 2 FADH2

69
Q

Stage 3: Oxidative Phosphorylation

A

Involves ETC & Chemiosmosis

70
Q

Electron Transport Chain (ETC) (in OP)

A

occurs in mitochondria inner membrane (phospholipid bilayer)
produces 26-28 ATP (MOST of all stages) by oxidative phosphorylation via chemiosmosis

71
Q

Chemiosmosis in OP

A

H+ ions pumped across
inner mitochondrial
membrane
H+ diffuse back into ATP
synthase (protein) only if make ATP for use (ADP → ATP)

72
Q

ETC

A

Collection of molecules embedded in inner membrane of mitochondria
Tightly-bound protein + non protein components
Alternate between reduced/oxidized states as accept/donate e-
DOES NOT make ATP directly
Eases fall of e- from food to O2
2H+ +1/2 O2 -> MAKES WATER

73
Q

ETC (CATFISHING) in OP

A

NADH catfishes H+ bc carries e- from food that attracts H+ OUT to intermembrane space thru proton pumps in proteins to cross hydrophobic phospholipid bilayer

74
Q

Chemiosmosis: ENERGY COUPLING MECHANISM

A

Chemiosmosis = H+ gradient across
membrane drives cellular work (ONLY lets IN H+ back into matrix if MAKE ATP)
Proton-motive force allows
ATP synthase (enzyme): MAKES ATP by Energy from proton (H+) gradient –flow of H+ back into matrix

75
Q

Overall View of Oxidative Phosphorylation

A

Uses chemiosmosis which couples proton gradient aka proton motive force -> drives H+ thru ATP Synthase to produce ATP -> uses E -> for redox RXN of ETC -> where e- passed down E levels to (H+ pumped from matrix to intermembrane space of proton gradient) -> terminal e- acceptor (O2) + makes H2O

76
Q

ATP yield per molecule of glucose at each stage of cellular respiration

A

Glycolysis: 2 ATP
Cyctric Acid (Krebs cycle): 2 ATP
Oxidative Phosphorylation: 26-28 ATP

77
Q

Anaerobic Respiration

A

Generate ATP using other e- acceptors besides O2
Final e- acceptors: sulfate (SO4), nitrate, sulfur (produces H2S)
Ex: Obligate anaerobes: can’t survive in O2

78
Q

Facultative anaerobes

A

Make ATP by Aerobic
Respiration (with O2 present) or switch to Fermentation (no O2 available)
Ex: human muscle cells

79
Q

Fermentation

A

Glycolysis + Regeneration of NAD+ when O2 is NOT present
pyruvate -> ethanol, lactate etc

80
Q

Types of Fermentation

A

Alchohol & Lactic Acid

81
Q

Alchohol Fermentation

A

Takes pyruvate -> Ethanol + CO2
ex: bacteria & yeast
used for brewing, winemaking, baking

82
Q

Lactic Acid Fermentation

A

Pyruvate -> Lactate (lactic acid)
ex: fungi, bacteria, human muscle cells
used to make cheese, yogurt, acetone, methanol
note: lactate build-up does NOT cause muscle fatigue & pain

83
Q

Glycolysis WITHOUT O2 (terminal e- acceptor)

A

FERMENTATION
Keep glycolysis going by regenerating NAD+
Occurs in cytosol
No oxygen needed
Creates ethanol [+CO2] or lactate
2 ATP (from glycolysis)

84
Q

Glycolysis WITH O2 present (terminal e- acceptor)

A

RESPIRATION
Release E from breakdown of food w/ O2
Occurs in mitochondria
O2 required (final electron acceptor)
Produces CO2, H2O & up to 32 ATP

85
Q

Various sources of fuel

A

Carbohydrates, fats & proteins can ALL be used as fuel for Cellular
Respiration
Monomers enter glycolysis / citric acid cycle at different points

86
Q

Phosphofructokinase (PFK)

A

Allosteric (alter protein activity) enzyme that controls rate of glycolysis & citric acid cycle
Inhibited by ATP, citrate
Stimulated by AMP
AMP+ P + P →ATP

87
Q

Big Picture of Cellular Respiration

A

Energy -> Glycolysis (cytosol) -> substrate-level phosphorylation

ALSO Glycolysis w/ O2 -> Pyruvate Oxidation -> Citric Acid (Krebs) Cycle -> substrate-level phosphorylation +
-> Oxidative Phosphorylation (ETC & Chemiosmosis)

Glycolysis anaerobic w/o O2 -Fermentation (cytosol) -> Ethanol + CO2 (yeast some bacteria) OR Lactic Acid

88
Q

Photosynthesis in Nature

A

Plants and other autotrophs are producers of biosphere

89
Q

Photoautotrophs

A

Use light E (sun) to make organic molecules
(Eats energy from sun)

90
Q

Heterotrophs

A

Consume organic molecules from other organisms for E and carbon (eats other things)

91
Q

Photosynthesis

A

Converts light energy to Chemical Energy of food

92
Q

Chloroplasts

A

Sites of photosynthesis in plants

93
Q

Sites of Photosynthesis

A

Mesophyll, Stomata, Chloroplast

94
Q

Mesophyll

A

Chloroplasts mainly found in these cells of leaf

95
Q

Stomata

A

Pores in leaf (CO2 enter/O2 exits)

96
Q

Chlorophyll

A

Green pigment in thylakoid membranes of chloroplasts (absorbs sunlight)

97
Q

Photosynthesis EQ

A

6CO2 + 6H2O + Light Energy → C6H12O6 + 6O2
Redox Reaction: water is split → e- transferred with H+ to CO2 → sugar
Remember: OILRIG
Oxidation: lose e-
Reduction: gain e-

98
Q

Tracking atoms through photosynthesis

A

Evidence that chloroplasts split water molecules allowed researchers to track atoms through photosynthesis

99
Q

Photosynthesis def

A

Light Reactions + Calvin Cycle
“photo” “synthesis” (make)
Endergonic (absorbs sun E) & Anabolic builds glucose

100
Q

Overall Photosynthesis Image

A

In chloroplast, light & H2O enter into thykaloid stacks w/ Chlorophyll (LIGHT RXNs) -> gives off O2 + gives ATP & NADH -> Calvin Cycle which absorbs CO2 & gives off CH2O (sugar) -> gives Light RXNs ADP + Pi & NADP+

101
Q

Light RXNs

A

Convert solar E to chemical E of ATP & NADPH

102
Q

Nature of sunlight

A

Light = Energy = Electromagnetic Radiation
Shorter wavelength (λ): higher E
Visible light - detected by human eye
Light: reflected, transmitted or absorbed

103
Q

Electromagnetic Spectrum

A

the SHORTER the wavelength (purple, blue) the MORE E
the HIGHER the wavelength (red) the LOWER E

104
Q

Interaction of Light w / Photosynthesis

A

BC Chloroplast/Chlorophyll = Green it absorbs EVERY color BUT green (REFLECTS GREEN)

105
Q

Photosynthetic Pigments

A

Pigments absorb different λ of light
Chlorophyll – absorb violet-blue/red light, reflect green

106
Q

Chlorophyll a

A

(Blue-Green): light RXN, converts solar to chemical E

107
Q

Chlorophyll b

A

(Yellow-Green): conveys E to chlorophyll a

108
Q

Carotenoids

A

(Yellow, Orange): photoprotection, broaden color spectrum for
photosynthesis

109
Q

Absorption Spectrum

A

Determines Effectiveness of
Different Wavelengths for Photosynthesis
Ex: Green = high transmittance but low absorption
Blue = low transmittance but high absorption

110
Q

Action Spectrum

A

Plots Rate of Photosynthesis vs. Wavelength
(absorption of chlorophylls a, b, &
carotenoids combined)

111
Q

Engelmann

A

Used bacteria to measure rate of photosynthesis in algae; established action spectrum

112
Q

Which wavelengths of light are
most effective in driving
photosynthesis?

A

Purple/Blue & Red

113
Q

Light RXNs

A

e- in chlorophyll molecules are excited by absorption of light, gives off heat
energy of e- -> photon -> chlorophyll (excited) gives off heat & photon fluorescence

114
Q

Photosystem

A

Reaction center & Light-harvesting
Complexes (pigment + protein),

115
Q

2 Routes of e- flow for Light RXNs

A

A. Linear (noncyclic) electron flow
B. Cyclic electron flow

116
Q

Light Reaction (LINEAR e- flow)

A

light E absorbed by Chlorophyll molecules thru photons is used to EXCITE/energize e- that power proton pumps (proton gradient)
1. E passed to reaction center of Photosystem II (protein + chlorophyll a)
2. e- captured by PRIMARY e- ACCEPTOR
3. Redox reaction → e- transfer
4. e- prevented from losing E (drop to ground state)
5. H2O is split to replace e- → H+, e-, O2 formed (ripping apart covalent bonds )
6. e- passed to Photosystem I via ETC
7. E transfer pumps H+ to thylakoid space
8.ATP produced by photophosphorylation
9. e- moves from PS I’s primary electron
acceptor to 2nd ETC
10. NADP+ reduced to NADPH

117
Q

Main Idea of Linear Light RXN

A

Use solar E to generate ATP (atp synthase & chemiosmosis) &
NADPH to provide E for Calvin cycle

118
Q

Cyclic Electron Flow (Light RXN)

A

Uses PS I ONLY; produces ATP for
Calvin Cycle (NO O2 or NADPH produced)
Makes free ATP as long as sunlight, lots of E from protons (sun)

119
Q

Both Respiration & Photosynthesis do what?

A

Use Chemiosmosis to generate ATP, ATP synthase, photophosphorylation

120
Q

How is the formation of a proton gradient in light reactions used to form ATP from ADP plus inorganic phosphate by ATP
synthase.

A

A proton gradient is created as the first ETC moves H+ ions through the cytochrome complex. ATP synthase then works like a gear to create ATP from ADP and inorganic phosphate.

121
Q

Proton Motive Force generated by

A

1) H+ from water
2) H+ pumped across by cytochrome
3) Removal of H+ from stroma when NADP+ is reduced

122
Q

Calvin Cycle

A

In stroma
Uses ATP & NADPH to convert CO2 to sugar
Uses ATP, NADPH, CO2
Produces 3-C sugar G3P (glyceraldehyde-3-phosphate) used in cellular respiration

123
Q

3 Phases of Calvin Cycle

A

1) Carbon fixation
2) Reduction
3) Regeneration of RuBP (CO2 Acceptor)

124
Q

Phase 1: Calvin Cycle (Carbon Fixation)

A

3 CO2 + RuBP (5-C sugar ribulose
bisphosphate)
Catalyzed (cause/accelerated) by Enzyme Rubisco (RuBP (chemical change = enzyme)
shapes CO2 to 5 chain the we cut it to get 6 3-phosphoglycerate

125
Q

Phase 2: Calvin Cycle (Reduction)

A

Use 6 ATP & 6 NADPH (changes to 6NADP+) to
Produce 1 net: G3P (1 sugar)

126
Q

Phase 3: Calvin Cycle - Regeneration of RuBP (CO2 Acceptor)

A

Use 3 ATP to regenerate 3 RuBP (creates 3 ADP)

127
Q

What does calvin cycle give back to Light RXNs?

A

NADP+ provides electrons to facilitate rxns
ATP-> ADP releases energy to power metabolic processes

128
Q

Alternative mechanisms of carbon fixation have evolved in
hot, arid climates

A

Photorespiration

129
Q

Photorespiration

A

Metabolic pathway which: Uses O2 & produces CO2
Uses ATP
No sugar production (rubisco binds O2 → breakdown
of RuBP)
Occurs on hot, dry bright days when stomata close bc absorbs CO2 (conserve H2O)
Why? Early atmosphere: low O2, high CO2?

130
Q

Evolutionary Adaptations

A

Problem with C3 Plants:
CO2 fixed to 3-C compound in Calvin cycle
Ex. Rice, wheat, soybeans
Hot, dry days: partially close stomata, ↓CO2
Photorespiration
↓ photosynthetic output (no sugars made)

131
Q

C4 Plants

A

CO2 fixed to 4-C compound
Ex. corn, sugarcane, grass
Hot, dry days → stomata close (absorbs CO2)
2 cell types = mesophyll & bundle sheath cells (mesophyll: pyruvate fixes & grabs CO2 to hold onto it = pump to other cells)

132
Q

C4 plants (continued)

A

Mesophyll : PEP carboxylase fixes CO2 (4-C), pump CO2 to bundle sheath
Bundle sheath: CO2 used in Calvin cycle
↓ photorespiration(plants eathing themselves bc not enough water), ↑sugar production (efficient for areas that are hot & dry dont lose as much water)
WHY? Advantage in hot, sunny area

133
Q

CAM Plant

A

Crassulacean acid metabolism (CAM)
NIGHT: stomata open → CO2 enters → converts to organic acid, stored in mesophyll cells
DAY: stomata closed → light reactions supply: ATP, NADPH; CO2 released from organic acids
for Calvin cycle
Ex. cacti, pineapples, succulent (H2O-storing) plants
WHY? Advantage in arid conditions

134
Q

Comparing C3, C4, CAM Plants

A

C3: C fixation & Calvin
together, Rubisco
C4: C fixation & Calvin
in different cells, PEP carboxylase
CAM: C fixation & Calvin
at different TIMES, Organic acid

135
Q

Importance of Photosynthesis

A

Plant: Glucose for respiration, Cellulose
Humans: O2 Production, Food source

136
Q

(Respiration!!!) Vs. Photosynthesis

A

RESPIRATION
Plants + Animals
Needs O2 & food
Produces CO2, H2O & ATP, NADH
Occurs in mitochondria membrane &
matrix
Oxidative phosphorylation
Proton gradient across membrane

137
Q

Respiration Vs. (Photosynthesis!!!)

A

Photosynthesis
Plants
Needs CO2, H2O, sunlight
Produces glucose, O2 ATP,
NADPH
Occurs in chloroplast thylakoid
membrane & stroma
Photorespiration
Photophosphorylation
Proton gradient across membrane

138
Q

Overview Of Photosynthesis

A

Photosynthesis -> Light ENERGY stored in organic molecules
Photosynthesis -> light RXN -> H20 Split -> O2 evolved
Photosynthesis -> light RXN- > in which energized e- reduce NADPH + -> pass down ETC by mechanism -> chemiosmosis -> in process: photophosphorylation + -> ATP
Photosynthesis -> Calvin Cycle -> Co2 fixed to RuBP -> C3 Phosphorylated & Reduce NADP+ using ATP to form G3P -> Regenerate RuBP using ATP + -> glucose & other carbs (G3P)

139
Q

Overview of Whole Photosynthesis Process

A

H20 & Light E enters Chloroplast (Chlorophyll) inside thykaloid stacks = light RXNS P(Photosyst 2, ETC, Photosyst 1, ETC) -> O2 released then ATP & NADPH transferred to Calvin Cycle: CO2 enters -> 3 phosphoglycerate -> G3P -> starch storage & sucrose export released, then turns into RuBP to give back ADP & NADP+ to LIGHT RXN

AP Bio (8 decks)

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