1. AP Bio Exam Review: Unit 3 & 4: Cells Energy (Respiration & Photosynthesis)

2. Catabolic pathways release energy by breaking down complex molecules into simpler compounds. (exergonic)
C6H12O6 + 6O H2O + 6CO2 + E
Anabolic pathways consume energy to build complex molecules from simple ones.(Endergonic)
6H20 + 6CO2 + E C6H12O6 + 6O2

3. Enzymes speed up metabolic reactions by lowering energy barriers
A catalyst is a chemical agent that speeds up a reaction without being consumed by the reaction
An enzyme is a catalytic protein
Ex: Hydrolysis of sucrose by the enzyme sucrase is an example of an enzyme-catalyzed reaction

4. Substrate Specificity of Enzymes
The reactant that an enzyme acts on is called the enzyme’s substrate
The enzyme binds to its substrate, forming an enzyme-substrate complex
The active site is the region on the enzyme where the substrate binds

7. Cofactors Enzyme Inhibitors
Cofactors are nonprotein enzyme helpers
Coenzymes are organic cofactors such as vitamins
Enzyme Inhibitors

8. Allosteric Regulation
Allosteric regulation may either inhibit or stimulate an enzyme’s activity

9. Mitochondrion Structure
Citric Acid Cycle
(matrix)
ETC
(inner membrane)

10. Cellular Respiration

11. Glycolysis Without O2 O2 present Fermentation Cell Respiration
Occurs in plants and animals
Occurs in cytosol
Keep glycolysis going
No oxygen needed
Anaerobic respiration
Creates alcohol [+ CO2] or lactic acid
Release E from breakdown of food with O2
Occurs in mitochondria
O2 required (final electron acceptor)
Aerobic respiration
Produces CO2, H2O and up to 38 ATP (NADH, FADH2)

12. PURPOSE = NAD+ recycled for glycolysis
Types of Fermentation
Alcohol fermentation
Lactic acid fermentation
Pyruvate  Ethanol + CO2
Ex. bacteria, yeast
Used in brewing, winemaking, baking
Pyruvate  Lactate
Ex. fungi, bacteria, human muscle cells
Used to make cheese, yogurt, acetone, methanol
PURPOSE = NAD+ recycled for glycolysis

13. Food  NADH & FADH  ETC  O2
Energy Harvest
Broken down into steps:
Food  NADH & FADH  ETC  O2
Consumes glucose (sugar)
pyruvates
Aerobic or anaerobic respiration
Acetyl CoA or lactic acid/ethanol
Krebs cycle
NADH & FADH carries electrons to the electron transport chain (ETC)
ETC: transfers e- to O2 to make H2O ; releases ATP

14. Various sources of fuel
Carbohydrates, fats and proteins can ALL be used as fuel for cellular respiration
Monomers enter glycolysis or citric acid cycle at different points

15. ENERGY glycolysis Respiration Krebs cycle fermentation ethanol + CO2
aerobic (with O2)
anaerobic (without O2)
glycolysis
(cytosol)
Respiration
(mitochondria)
substrate-level phosphorylation
Krebs cycle
(citric acid cycle)
fermentation
electron transport chain
Oxidative Phosphorylation
ethanol + CO2
(yeast, some bacteria)
lactic acid
(animals)
chemiosmosis

16. Photosynthesis = Light Reactions + Calvin Cycle

17. Parts of a chloroplast

18. Sites of Photosynthesis
Leaf cross section
Vein
Mesophyll
Stomata
CO2 O2
Mesophyll cell
Chloroplast
5 µm
Outer
membrane
Intermembrane
space
Inner membrane
Thylakoid
Granum
Stroma
1 µm
mesophyll: chloroplasts mainly found in these cells of leaf
stomata: pores in leaf (CO2 enter/O2 exits)
chlorophyll: green pigment in thylakoid membranes of chloroplasts

19. Light Reactions

21. Calvin Cycle = produce 3C sugar (G3P)

22. Overview of Photosynthesis

23. Both respiration and photosynthesis use chemiosmosis to generate ATP

24. Photorespiration: low carbon-fixation when stomata closed in hot, dry climate
CAM
C fixation & Calvin together
C fixation & Calvin in different cells
C fixation & Calvin at different TIMES
Rubisco
(normally fixes CO2)
PEP carboxylase fixes CO2
Organic acid
Mesophyll cells
Mesophyll: fix CO2
Bundle Sheath: Calvin Cycle
Night: fix CO2 in 4C acids
Day: Calvin Cycle
Ex. rice, wheat, soybeans
Ex. sugarcane, grass
Ex. cacti, pineapple, succulent

25. Parts of a plant used to adapt to environment
Roots – uptake of water (transpiration)
Leaves – stomata
Branches or trunk of plant
Vascular bundle (veins) = (xylem & phloem)
Seeds – reproduction

26. Transpiration
*upward movement of water and minerals from roots and shoots via the xylem
*water is lost from the leaves of the plant to oxygen
*Large leaf surface are increases photosynthesis but also increases water loss by the plant through stomata.
*Stomata are open – CO2 moves inward
*Stomata are closed – preserve H2O
*Water is pulled up by cohesion forces, adhesion forces

27. Plant hormones Important plant hormones:
Auxin – stimulate cell elongation
Cytokinins – cell division (cytokinesis) & differentiation
Gibberellins – stem elongation, leaf growth, germination, flowering, fruit development
Abscisic Acid – slows growth; closes stomata during H2O stress; promote dormancy
Ethylene gas – promote fruit ripening (positive feedback!); involved in apoptosis (shed leaves, death of annuals)

28. Photoperiodism Tropisms Plants detect light & wavelength
Ex: flowering of plants
Tropisms
Growth of plant toward or away from stimulus
Thigmotropism – Touch
Geotropism – gravity
Phototropism - light

30. Comparison RESPIRATION PHOTOSYNTHESIS Plants + Animals
Needs O2 and food
Produces CO2, H2O and ATP, NADH
Occurs in mitochondria membrane & matrix
Oxidative phosphorylation
Proton gradient across membrane
Plants
Needs CO2, H2O, sunlight
Produces glucose, O2 and ATP, NADPH
Occurs in chloroplast thylakoid membrane & stroma
Photorespiration
Proton gradient across membrane

31. The End