Unit 3: Cells Processes Unit 3: Cells Processes (Photosynthesis & (Photosynthesis &

Respiration)Respiration)

I.I. Cell EnergyCell EnergyA.A. ATPATP

All cells (plant, animal, bacteria, etc.) need All cells (plant, animal, bacteria, etc.) need energy for active transport, cell division, energy for active transport, cell division, movement of flagella or cilia, muscle movement of flagella or cilia, muscle contraction, etc.contraction, etc.

AAdenosine denosine ttriripphosphate (ATP) stores energy in hosphate (ATP) stores energy in the chemical bonds between the 3 phosphate the chemical bonds between the 3 phosphate groups. The third phosphate bond is weak and groups. The third phosphate bond is weak and when broken, releases energywhen broken, releases energy• AMP = one phosphate groupAMP = one phosphate group• ADP = two phosphate groupsADP = two phosphate groups

lesser/no energy available

B. Food you eat is digested to make the ATP you need.B. Food you eat is digested to make the ATP you need.

* most commonly used* most commonly used

MacromoleculeMacromolecule

broken downbroken down

Energy releasedEnergy released

Carbohydrate *Carbohydrate * 4 calories/mg4 calories/mg

LipidLipid 9 cal/mg9 cal/mg

ProteinProtein 4 cal/mg4 cal/mg

II. PhotosynthesisII. Photosynthesis process where autotrophs convert sunlight into process where autotrophs convert sunlight into

chemical energy & supports virtually all life on Earthchemical energy & supports virtually all life on Earth energy stored as sugars which are used by energy stored as sugars which are used by

heterotrophsheterotrophs occurs in plants and some algaeoccurs in plants and some algae takes place in the takes place in the chloroplastschloroplasts, using , using chlorophyll chlorophyll

6CO6CO22 + 6H + 6H220 C0 C66HH1212OO6 6 + 6O + 6O22

Organisms that do NOT require sunlight to make Organisms that do NOT require sunlight to make energy use chemosynthesis (convert chemical energy energy use chemosynthesis (convert chemical energy to make energy storing carbon compounds). These to make energy storing carbon compounds). These include archaebacteria in extreme environments like include archaebacteria in extreme environments like deep ocean thermal vents.deep ocean thermal vents.

A. Light Dependent ReactionA. Light Dependent Reaction1. occurs in thylakoid membrane of chloroplast 1. occurs in thylakoid membrane of chloroplast

2. begins when energy from sunlight is absorbed by 2. begins when energy from sunlight is absorbed by

pigments in photosystem IIpigments in photosystem II

3. H3. H22O molecules are split into OO molecules are split into O2 2 (released), H(released), H++ and and

high energy electrons (ehigh energy electrons (e--))

4. H4. H+ + ions build up in thylakoid and move through ATP ions build up in thylakoid and move through ATP

synthase into stroma, providing energy to make ATPsynthase into stroma, providing energy to make ATP

5. e5. e- - go through electron transport chain to photosystem I, go through electron transport chain to photosystem I,

where they are accepted by NADPwhere they are accepted by NADP++ along with H along with H++ to to

form NADPHform NADPH

B. Light Independent ReactionB. Light Independent Reaction1. also called Calvin cycle or dark reaction 1. also called Calvin cycle or dark reaction

2. occurs in stroma (fluid outside thylakoid) of 2. occurs in stroma (fluid outside thylakoid) of chloroplast chloroplast

3. light not required3. light not required

4. CO4. CO22 enters undergoes a series of reactions to build enters undergoes a series of reactions to build

high–energy compounds, (G3P then glucose) high–energy compounds, (G3P then glucose) using using energy from ATP and NADPH (from the light energy from ATP and NADPH (from the light

dependent reaction) dependent reaction)

5.5. These sugars are either stored (as starch or These sugars are either stored (as starch or cellulose) cellulose)

or used by the plant for growth & developmentor used by the plant for growth & development

II.II. Cellular RespirationCellular RespirationA.A. Overview/EquationOverview/Equation

all organisms must breakdown compounds to all organisms must breakdown compounds to make ATP energymake ATP energy

cellular respiration involves the breakdown of cellular respiration involves the breakdown of carbon containing molecules in the presence of Ocarbon containing molecules in the presence of O22 to make ATP in the mitochondria of eukaryotic to make ATP in the mitochondria of eukaryotic cellscells

CC66HH1212OO6 6 + 6O + 6O2 2 6CO6CO22 + 6H + 6H220 0 (MEMORIZE!!)(MEMORIZE!!)

it is a 3 step it is a 3 step aerobicaerobic process that begins with process that begins with glycolysisglycolysis

B.B. Glycolysis Glycolysis – anaerobic process where – anaerobic process where glucose is broken down in cytoplasm of cellsglucose is broken down in cytoplasm of cells

Glucose is broken down into 2 simpler 3-carbon Glucose is broken down into 2 simpler 3-carbon molecules called pyruvatemolecules called pyruvate

2 molecules of ATP are also produced (only 2% of 2 molecules of ATP are also produced (only 2% of total chemical energy in glucose)total chemical energy in glucose)

C.C. Aerobic RespirationAerobic Respiration1.1. Krebs cycle (Citric acid cycle)Krebs cycle (Citric acid cycle) – if O – if O22 is present, then is present, then

pyruvate moves into matrix of mitochondriapyruvate moves into matrix of mitochondria Each pyruvate “turns” the Krebs cycle once, Each pyruvate “turns” the Krebs cycle once,

releasing 3 COreleasing 3 CO22 and one ATP molecule (a net and one ATP molecule (a net

of 6 COof 6 CO22 and 2 ATP) and 2 ATP) Energy is transferred to next stepEnergy is transferred to next step

2. 2. Electron Transport ChainElectron Transport Chain Occurs in cristae (inner membrane) of Occurs in cristae (inner membrane) of

mitochondriamitochondria ATP is produced (32 or 34 ATP) which is ATP is produced (32 or 34 ATP) which is

used for multiple life processesused for multiple life processes OO22 is used and reacts with H is used and reacts with H++ and e and e-- to make to make

HH22O (6 OO (6 O2 2 will produce 6 Hwill produce 6 H22O)O)

D.D. Anaerobic Respiration (Fermentation)Anaerobic Respiration (Fermentation) occurs when not enough/no Ooccurs when not enough/no O22 is present in cells is present in cells does NOT make ATP, but allows glycolysis to does NOT make ATP, but allows glycolysis to

continue, which makes small amounts of ATPcontinue, which makes small amounts of ATP

1.1. Lactic acid fermentationLactic acid fermentation – converts – converts pyruvate pyruvate

to lactic acidto lactic acid• occurs when muscles run out of Ooccurs when muscles run out of O22 (during (during

intense exercise, etc.)intense exercise, etc.)• ““burning” of muscles, sorenessburning” of muscles, soreness• lactic acid is diffused back into blood and lactic acid is diffused back into blood and

transported to liver where it is converted back transported to liver where it is converted back to pyruvateto pyruvate

2.2. Alcoholic FermentationAlcoholic Fermentation – – converts converts

pyruvate to COpyruvate to CO22 and ethanol (ethyl alcohol) and ethanol (ethyl alcohol)

• used by yeast and some plants; COused by yeast and some plants; CO22

makes breads rise, the ethanol evaporates makes breads rise, the ethanol evaporates during cookingduring cooking

• produces wines, beers and other ethanol produces wines, beers and other ethanol beveragesbeverages

Note:Note: These are the 2 most common types of These are the 2 most common types of fermentation. Bacteria use other types to produce fermentation. Bacteria use other types to produce yogurts, cheeses and aid in digestionyogurts, cheeses and aid in digestion