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Energy in cells (Photosynthesis and Respiration)

Energy in cells (Photosynthesis and Respiration)

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Page 1: Energy in cells (Photosynthesis and Respiration)

Energy in cells

(Photosynthesis and Respiration)

Page 2: Energy in cells (Photosynthesis and Respiration)

Photosynthesis

• Chemical process that captures light energy and stores it as Chemical Potential Energy, only occurs in autotrophs

• Is a series of reactions controlled by enzymes• Occurs in the …• 2 Stages

– Light phase 1– Dark phase 2

Page 3: Energy in cells (Photosynthesis and Respiration)

Structure of a chloroplast

Granum – stacked thylakoids containing chlorophyll.

Stroma – clear liquid interior

How can you tell which phase occurs where?

How has surface area been maximised?

What is the green colour from?

Page 4: Energy in cells (Photosynthesis and Respiration)

Photosynthesis

The purpose is to capture light energy from the sun and store it as chemical energy in glucose molecules for use inside the plants. It also:•Removes carbon dioxide from the air •Needs water, gained by osmosis from the soil into the root hair cells and up the xylem vessels•Makes oxygen gas for use in respiration in all living organisms

Photosynthesis reaction summary:

Carbon dioxide + water glucose + oxygen + water

CO2 + H2O C6H12O6 + O2 + H20

Page 5: Energy in cells (Photosynthesis and Respiration)

Stages in PhotosynthesisStage Raw

materialsSource of raw materials

Products

(waste)

Location within

Chloroplast

Phase 1. Light or Light Dependent (LD)

Phase 2. Dark or Light Independent (LI)

Page 6: Energy in cells (Photosynthesis and Respiration)

Stages in PhotosynthesisStage Raw

materialsSource of raw materials

Products

(waste)

Location within

Chloroplast

Phase 1. Light or Light Dependent (LD)

Light

Water

ADP

NAPH

Sun

Air

Dark Reaction

ATP

NADPH2

(Oxygen)

Thylakoids of Grana

Phase 2. Dark or Light Independent (LI)

Carbon Dioxide

ATP

NADPH2

Air

Light Reaction

ADP

NAPH

Glucose

Stroma

Page 7: Energy in cells (Photosynthesis and Respiration)

Carrier molecules in Photosynthesis

• ATP – the energy carrier– ADP (empty)– Transports energy from light phase to dark

phase

• NADP – the hydrogen carrier– NADPH2 (full)– Transports hydrogen from light phase to dark

phase

Page 8: Energy in cells (Photosynthesis and Respiration)

See handout and discuss this concept in relation to the leaf model and the chloroplast diagram

How plants maximise the rate of photosynthesis

Page 9: Energy in cells (Photosynthesis and Respiration)

Factors affecting photosynthesis reaction rate:

Photosynthesis is controlled by enzymes so anything that affects enzymes also affects photosynthesis, including;•Light intensity (can differ for different plants, canopy verses forest floor plants), no photosynthesis in the dark!•Temperature (most plants have an optimum range)•CO2 concentration (substrate concentration)•Low water availability causes the stomata to close and CO2 diffusion to stop so photosynthesis stops as well.

Page 10: Energy in cells (Photosynthesis and Respiration)

Respiration

All living cells must carry out cellular respiration and the purpose is too release the energy stored in food (glucose) and make it available to power all other metabolic reactions (in both autotrophs and heterotrophs)

•Occurs in the (name organelle here?)

•There are two types (aerobic and anaerobic)

Page 11: Energy in cells (Photosynthesis and Respiration)

Structure of a mitochondriaCristae are the folded inner membranes. Why are they folded?

The matrix is the liquid inside . What stages take place here?

Mitochrondria are found in all living cells but in general animals cells have more than plants and any cells that need more energy have more e.g. muscle and liver cells have high energy demands so have more….

Page 12: Energy in cells (Photosynthesis and Respiration)

Aerobic Respiration (with O2)

• Cellular respiration with oxygen

• Also a series of reactions controlled by enzymes

• Glucose (food) and oxygen convert to lots of energy (ATP) with waste products of CO2 and H2O

C6H12O6 + 6O2 6CO2 + 6H2O + ATP glucose oxygen carbon dioxide water energy

Page 13: Energy in cells (Photosynthesis and Respiration)

4 stages of aerobic respiration

Stage Name Location in cell

Energy (ATP) produced

Link to equation

1

2

3

4

Page 14: Energy in cells (Photosynthesis and Respiration)

4 Stages of aerobic respiration (with oxygen)

– Glycolysis, – Link reaction , – Krebs cycle, – Electron transport chain

These stages are linked by carrier molecules in a similar way to photosynthesis reactions…

Page 15: Energy in cells (Photosynthesis and Respiration)

4 stages of aerobic respirationStage Name Location in

mitochondria or cell

Energy (ATP) produced

Link to equation

1 Glycolysis

(breakdown of glucose)

Cytoplasm 2 ATP Forms Pyruvate

No O2 needed

2 Link reaction Matrix none Forms Acetyl Co enzyme A and CO2

No O2 needed

3 Krebs Cycle or Citric Acid Cycle

Matrix 2 ATP Produces H2

No O2 needed

4 Electron Transfer Chain

Cristae 32 ATP O2 needed, combines with H2 to produce H2O

Page 16: Energy in cells (Photosynthesis and Respiration)

Carrier molecules in respiration (molecules that link stages of aerobic respiration)

• Co-enzyme A – an acetyl carrier– Acetyl co-enzyme A (full)– Transports acetyl group from glycolysis to

Krebs cycle

• NAD – the hydrogen carrier– NADH2 (full)– Transports hydrogen from Krebs cycle to

Electron transport chain

Page 17: Energy in cells (Photosynthesis and Respiration)

Anaerobic respiration (no O2)

• Respiration without oxygen• Another series of reactions controlled by

enzymes• Stops after glycolysis (stage 1)• Much less energy (ATP) produced• Different waste or by-products produced

• PlantsGlucose carbon dioxide + ethanol + 2ATP

• AnimalsGlucose lactic acid + 2ATP

Page 18: Energy in cells (Photosynthesis and Respiration)

Factors affecting respiration

All respiration reactions are controlled by enzymes …so again all things that effect enzymes affect both types of respiration, plus:

• Too much toxic product. Too much carbon dioxide (aerobic respiration) and too much ethanol or lactic acid (anaerobic respiration) is toxic. Toxic products must be removed during respiration for it to continue efficiently.

Page 19: Energy in cells (Photosynthesis and Respiration)

See Factors Affecting Enzymes…

•Temperature, •pH, •Surface Area, •Substrate (reactant) concentration,•Enzyme concentration, •Co-Factors (enzyme helpers), •Inhibitors (heavy metals, poisons).

Page 20: Energy in cells (Photosynthesis and Respiration)

ATP

• Adenosine triphosphate (ATP) is the universal energy carrier in all cells

• Cellular respiration is the process of recharging ADP (Adenosine diphosphate) to ATP

P

P

P

P

P

P

Page 21: Energy in cells (Photosynthesis and Respiration)

Role of ATP (Energy carrier molecule)

ATP ADP

Energy releasedfrom breaking off onephosphate (-P) from ATP.Where?

-P

+P

Respiration recharges ADP to ATP using energy and adding one phosphate (+P). Where?

Page 22: Energy in cells (Photosynthesis and Respiration)

Energy in cells summary

P/S

Respiration

Light Energy

CO2and

H2OGlucose

O2

O2

All Autotroph and Heterotroph cells

ATP

Heat Energy

H2O

CO2

Photosynthetic Autotroph cells

ADPkJ

Page 23: Energy in cells (Photosynthesis and Respiration)