Biochemical Pathways Photosynthesis and Cellular Respiration

AUTOTROPHS ○ make their own food. ○ Ex: Phototrophs….Use light energy ○ Ex: Chemotrophs…Use inorganic compounds HETEROTROPHS ○ Must eat org. mol. for energy (carbon source).

Light  Form of energy Other forms: Other forms: ○ thermal, electrical, kinetic, sound, chemical  Travels in waves (diff. wavelengths)

Wavelength (λ)

FM The Electromagnetic Spectrum

Photosynthesis (Psyn):  Process: Light energy converts to chemical energy (sugars)  Pigments used to capture light energy

Pigments

Chlorophyll a  Chlorophyll a C 55 H 72 O 5 N 4 Mg Molecular wt Blue-Green (Not on test)

Chlorophyll b  Chlorophyll b C 55 H 70 O 6 N 4 Mg Molecular wt Yellow-Green (Not on test)

Anthocyanin  C 15 H 11 O + pp  Blue, red, pp  fruit, flowers (Not on test)

ß Carotene  C 40 H 56  Mol. wt  Orange Red  Orange, Red (Not on test)

Xanthophyll  C 40 H 56 O 2  Mol. Wt. 568  Yellow (Not on test)

Chromatography  Splitting pigments apart

 Evergreen plants psyn. year round.  Deciduous plants affected by temp. and light changes; leaves change color - drop.  Factors affecting the rate of psyn. Temperature Water availability Intensity of light CO 2 availability

Vocabulary  Chloroplast-  Chloroplast- plant cell organelle ; uses light energy to make chemical energy thru psyn., has chlorophyll  Chlorophyll-  Chlorophyll- pigment: captures light energy  Stoma- opening under leaves; allows CO 2 and O 2 to diffuse in/out of leaf. (stomata, pl.)  Thylakoids-  Thylakoids- saclike body in chloroplast; made of photosynthetic membranes  Granum-  Granum- stack of thylakoids (grana, pl.)  Stroma  Stroma- fluid region outside thylakoid membranes in chloroplast.  NADP + -  NADP + - molecule that carries energy and hydrogen - becomes NADPH  ATP  ATP- chemical compound used to store energy

A closer look at leaves:

See this web page

PHOTOSYNTHESIS Let’s draw this process… 6 CO H 2 O → C 6 H 12 O O 2 light energy Carbon dioxide and water are used to make sugar, with oxygen as a byproduct. Balanced equation

Chloroplast  Psyn. occurs here  Inside: chlorophylls Thylakoids = flattened membrane-bound sacks; has chlorophylls. Grana- stacks of thylakoids. Stroma= fluid matrix surrounding stacks.

Photosynthesis: two stages Light Dependent Reaction (LDR) Light Independent Reaction (LIR) or Calvin Cycle (used to be “dark Rx”) Both occur in chloroplast

Photosynthesis: Light Dependent Rx  light energy captured by chlorophyll  H 2 O split – photolysis  O 2 released  only takes place in light  occurs in thylakoids  makes NADPH & some ATP  nicotinamide adenine dinucleotide phosphate-oxidase

(Not on test)

Light Rx Process (site) ( Light reaction animation) (Not on test) (site) Light reaction animation

ATP Production during Aerobic Respiration involving the ETC and Chemiosmosis (Not on test) Chemiosmosis

Photosynthesis: Light Independent Rx (Calvin Cycle)  No light needed  occurs in stroma fluid outside thylakoids  NADPH & ATP powers cycle.  CO 2 is carbon source to make glucose

RESPIRATION: all organisms  Converts sugars to other power molecules  Stages: 1. Glycolysis THEN: 2a. Aerobic Resp. of Mitochondrion (in eukaryotes) OR: 2b. Anaerobic Resp. (Fermentation) (in pro/eu)

How do cells get energy from glucose?  GLYCOLYSIS  Splits glucose into 2 pyruvic acids cytosol Takes place in the cytosol Doesn’t need oxygen (anaerobic) Very fast process  GLYCOLYSIS  Splits glucose into 2 pyruvic acids cytosol Takes place in the cytosol Doesn’t need oxygen (anaerobic) Very fast process

C 6 H 12 O 6 2 Pyruvic acids (3C ea.) 2ATP 4 ADP 2NAD+ 4ATP 2NADH 2ADP CCCCCC CCC

Cellular Respiration Step 1  Glycolysis (in cytosol, anaerobic) Glycolysis  Requires 2 ATP to start the process  Net gain of 2 ATP and 2 NADH  2 pyruvic acids made

Cellular Respiration Step 2, 3 (in mitochondrion of eukaryotes)  Kreb’s Cycle- Kreb’s Cycle- Kreb’s Cycle- In matrix fluid- breaks pyruvic acids into acetyl CoA and CO 2 (2 ATP formed) In matrix fluid- breaks pyruvic acids into acetyl CoA and CO 2 (2 ATP formed)  Electron Transport chain- In cristae membrane: ATP synthase converts ADP to ATP (32 ATP formed) In cristae membrane: ATP synthase converts ADP to ATP (32 ATP formed)

CO 2 O2O2 H2OH2O

Total ATP Yields  Glycolysis 2 ATP  Krebs Cycle 2 ATP  Electron Transport 32 ATP  Total ATP from one glucose = 36 molecules.  C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + 36ATP This is the balanced equation for resp. This is the balanced equation for resp.

Respiration schematic

 Photosynthesis and Cellular Respiration form a continuous cycle : the products of one process are the reactants for the other.  Photosynthesis light 6CO 2 + 6H 2 O light C 6 H 12 O 6 + 6O 2  Cellular Respiration C 6 H 12 O CO H 2 O + energy (ATP) What’s the actual difference between the two (besides the order in which things appear)? How Energy Cycles

If NO Oxygen present…  Fermentation occurs (in cytosol) Sustains glycolysis Keeps 2 ATPs forming from each glucose Two types: ○ Alcoholic ferm. (in prokaryotes, some eukaryotes) Some bacteria, yeast. Byproducts: Ethyl alcohol and CO 2 ○ Lactic Acid ferm. (in YOU, and other eukaryotes) Muscle tissue Byproduct: Lactic acid

 How fermentation sustains glycolysis Keeps NADH cycle going