| Site of photosynthesis | - Leaf in eukaryotic plants
- Chloroplasts |
| Structure of the leaf adaptations | - LSA: absorbs as much sunlight as possible
- Leaves arranged to minimise overlapping: avoids shadowing
- Thin: shorter diffusion distance
- Transparent cuticle + epidermis: let light through to mesophyll cells
- Many stomata: gaseous exchange, short diffusion path to MC, open + close in response to light intensity
- Air spaces: lower mesophyll layer to allows rapid diffusion
- Xylem and phloem |
| Photosynthesis word equation | carbon dioxide + water ------> (light) glucose + oxygen |
| Metabolic pathway meaning | - A series of small reactions controlled by enzymes
e.g. photosynthesis and respiration |
| Phosphorylation meaning | - Adding phosphate to a molecule
e.g. ADP is phosphorylated to ATP |
| Photophosphorylation meaning | - Adding phosphate to a molecule using light |
| Photolysis meaning | - The splitting (lysis) of a molecule using light (photo) energy |
| Photoionisation meaning | - When light energy 'excites' electrons in in a molecule, giving them more energy + causing them to be released
- The release of electrons causes mol to become a +charged ion |
| Decarboxylation meaning | - The removal of carbon dioxide from a molecule |
| Dehydrogenation meaning | - The removal of hydrogen from a molecule |
| Redox reactions meaning | - Reactions that involve oxidation and reduction |
| The main stages of photosynthesis | - Capturing of light energy
- Light-dependent reaction
- Light-independent reaction |
| Capturing of light energy | - By chloroplast pigments such as chlorophyll |
| Light-dependent reaction | - Some light energy absorbed is conserved in chemical bonds
- During the process an electron flow is created by the effect of light on chlorophyll
- Causing water to slit (photolysis) into protons, electrons + oxygen
- Produces are reduced NADP, ATP + O2 |
| Light-independent reaction | - These protons used produce sugars + other organic molecules |
| Structure of chloroplasts | - The grana
- The thylakoids
- The stroma |
| The grana | - Grana are stacks of up to 100 disc like structure called thylakoids |
| The thylakoids | - Where light-dependent reactions happen
- Contains photosynthetic pigment, chlorophyll
- Some have tubular extensions that join up w/ thylakoids in adjacent grana, granal lamellae |
| The stroma | - Fluid-filled matrix
- Where light-independent stage of photosynthesis happens
- Within the stroma are the no. of other structure like starch grains |
| ATP properties that make it a good source of energy | - Stores or releases only a small, manageable amount of energy at a time, so no energy wasted as heat
- Easily broken down
- It can be quickly re-made
- Small, soluble molecule, easily transported around cell
- Can make other molecules more reactive by transferring one of its phosphate groups to them (phosphorylation) |
| What is ATP (recap) | - Cells cant get its energy directly from glucose
- So, in respiration, the energy released from glucose is used to make ATP
- ATP carries energy around the cell |
| How ATP works (recap) | - ATP is synthesised via condensation reaction (catalysed by ATP synthase) between ADP + an inorganic phosphate, using energy from an energy-releasing reaction
- Energy is stored as chemical energy in the phosphate bond
- ATP diffuses to the part of the cell that needs energy
- Here, its hydrolysed back into ADP + inorganic phosphate
- Chemical energy is released from the phosphate bond and used by the cell
- ATP hydrolyse catalyses this reaction
- The ADP + inorganic phosphate are recycled, the process starts again |
| Coenzymes | - A molecule that aids the function of an enzyme |
| How coenzymes work | - Transfers a chemical group from 1 molecule to another
- A coenzyme used in photosynthesis is NADP
- It transfers hydrogen from 1 molecule to another
- This means it can reduce (give hydrogen to) or oxidase (take hydrogen from) a moelcule |
| Examples of coezymes on resporaton | - NAD, coenzyme A and FAD
- NAD + FAD transfer hydrogen from 1 molecule to another
- This means that can reduce (give hydrogen to) or oxidase (take hydrogen from) another molecule
- Coenzyme A transfers acetate between molecules |
