Biology U3AOS2 Generalised

The general structure of the biochemical pathways in photosynthesis and cellular respiration from initial reactant to final product

Photosynthesis - 6CO2 + 12H2O --(sunlight)-> C6H12O6 + 6O2 + 6H2O

Cellular respiration - C6H12O6 + 6O2 ---> 6CO2 + 6H2O + 30/32 ATP

Anaerobic fermentation - C6H12O6 ---> Lactic acid + 2ATP (animals) OR Ethanol + 2CO2 + 2ATP (yeast)

The general role of enzymes and coenzymes in facilitating steps in photosynthesis and cellular respiration

Enzymes such as Rubisco are involved in photosynthesis as they 'fix' carbon into a form that can be used more efficiently by the plant. Coenzymes such as ATP/ADP+Pi, NAD(P)H/NAD(P)+ and FADH2/FAD+ provide energy for various reactions in both cellular respiration and photosynthesis

The general factors that impact on enzyme function in relation to photosynthesis and cellular respiration: changes in temperature, pH, concentration, competitive and non-competitive enzyme inhibitors

Temperature increases enzyme activity up to certain point (optimal temperature) where it will denature enzymes

pH decreases enzyme activity above and below the optimal range

Concentration of substrate will increase enzyme activity up to saturation point (all enzymes working). Concentration of enzymes will increase enzyme activity until there is no substrate left to act upon, and all enzymes are working.

Competitive inhibitors will decrease enzyme activity but can be outcompeted/dislodged by increased substrate concentration

Non-competitive inhibitors will permenantly hinder enzyme activity as they are irreversible

Inputs, outputs and locations of the light dependent and light independent stages of photosynthesis in C3 plants (details of biochemical pathway mechanisms are not required)

Light-dependent stage in grana and has equation 12H2O + 12NADP+ + 12 ADP+Pi --> 6O2 + 12NADPH + 12ATP

Light-independent stage in stroma and has equation 6CO2 + 12NADPH + 12ATP --> C6H12O6 + 12NADP+ + 12ADP+Pi + 6H2O

the role of Rubisco in photosynthesis, including adaptations of C3, C4 and CAM plants to maximise the efficiency of photosynthesis

Rubisco is an enzyme that fixes carbon into a form that can efficiently be used by plants within the Calvin cycle. C3 plants have no adaptations. C4 plants seperate the light-independent stage across space to prevent photorespiration. CAM plants seperate the light-independent stage across time to minimise photorespiration and reduce water loss

The factors that affect the rate of photosynthesis: light availability, water availability, temperature and carbon dioxide concentration

Light availability - The more light is available, the more photosynthesis is possible up to the light saturation point

Water availability - More water available, more inputs for photosynthesis, increases rate up to saturation point

Temperature - Affects enzymes within photosynthesis in normal manner

Carbon dioxide concentration - Affects photosynthesis rate as substrate concentration usually does

The main inputs, outputs and locations of glycolysis, Krebs Cycle and electron transport chain including ATP yield (details of biochemical pathway mechanisms are not required)

Glycolysis occurs in the cytosol, has equation C6H12O6 + 2ADP+Pi + 2NAD++H+ --> 2 pyruvate + 2ATP + 2NADH

Krebs cycle occurs in mitochondrial matrix, has equation 2 acetyl-CoA (derived from pyruvate) + 2ADP+Pi + 6NAD++H+ +2FAD+4H+ --> 4CO2 + 2ATP + 6NADH + 2FADH2

Electron transport chain occurs in cristal membrane, has equation 6O2 + 26/28ADP+Pi + 10NADH + 2FADH2 --> 6H2O + 26/28ATP + 10NAD++H+ + 2FAD+4H+

The location, inputs and the difference in outputs of anaerobic fermentation in animals and yeasts

Glycolysis occurs similarly in both plants and animals in the cytosol, prod. 2 pyruvate + 2 ATP. Then, in order to preserve NADH, 2 pyruvate is converted to 2 CO2 + 2 ethanol (in yeast) or lactic acid in animals

The factors that affect the rate of cellular respiration: temperature, glucose availability and oxygen concentration

Temperature - Same as normal temp. effect on enzyme activity.

Glucose availability - Glucose is an input of cellular respiration, so increase in availability increases rate upto saturation

Oxygen - Increases rate of aerobic respiration, as is req. for ETC up to saturation point. Too low O2 leads to unsustainable anaerobic resp.

Potential uses and applications of CRISPR-Cas9 technologies to improve photosynthetic efficiencies and crop yields

CRISPR-Cas9 can edit crops to increase yield, make them more appealing, increase photosynthetic efficiency, modify Rubisco action, change C3 plants to C4, CAM, increase resistance to bacteria/herbicides, modify taste

Uses and applications of anaerobic fermentation of biomass for biofuel production.

Biofuel is a fuel made from organic material.

Deconstruction - Biomass broken down to increase SA:V ratio, makes fermentation more efficient

Digestion by enzymes - Broken-down biomass exposed to enzymes that convert starch etc. into glucose

Ethanol fermentation - Yeast used to ferment sugars anaerobically, producing ethanol that diffuses out of yeasts

Purification and dehydration - Ethanol distilled via removal of water, converting it into biofuel