Importance Of Water

Question 1

AO1: Concepts about water being a major component in cells

Answer 1

> Metabolite - condensation & hydrolysis
Solvent - biochemical reactions
High specific heat capacity - buffer
Large latent heat of vaporisation - cooling effect

• Link to structure of water: Polar molecule, 2 different charged regions so H-bonds form between the H and O2 of 2 different water molecules

Question 2

AO2: Concepts about water being a major component in cells

Answer 2

Cohesion = surface tension -> habitat = help some organisms avoid predators within the water, can survive on the surface

Link to biodiversity increase (more habitats)

Buffer = maintain enzyme activity in changing environments

Question 3

AO1: Mass transport in plants - Transpiration, cohesion tension theory

Answer 3

Water moves through the xylem through cohesion between the water molecules and adhesion to the walls

• Link to structure of water

Question 4

AO2: Mass transport in plants

Answer 4

Water = solvent, carry dissolved ions e.g. nitrates that might’ve been absorbed from the cells

Combined with organic substances made in photosynthesis to make proteins such as the enzyme rubisco, which is essential in photosynthesis

Question 5

AO1: Photosynthesis- Light dependent reaction, photolysis

Answer 5

> Water is split into protons, electrons and oxygen using light energy

• Electrons replace those lost from the chlorophyll to the ETC, protons used to reduce NADP

Question 6

AO2: Photosynthesis

Answer 6

Create ATP and reduced NADP

Important for light independent reaction

ATP=hydrolysed to release energy for the regeneration of RUBP and for the reduction of GP->TP

Some of the carbon from TP is used to make the organic substances of a plant e.g. glucose - an essential respiratory substrate for the plant to produce ATP for all its metabolic processes

Question 7

AO1: Digestion and Absorption

Answer 7

> Hydrolysis = breaking bonds using water to split apart molecules

• e.g. starch -> maltose -> glucose

In depth about carbohydrate digestion

Mention the enzymes involved but MAIN FOCUS is the hydrolysis reactions

• Name bonds broken
• Splitting into smaller molecules —> Name the molecules

Question 8

AO2: Digestion and Absorption

Answer 8

> Glucose now small enough to be absorbed by co-transport into epithelial cells and the blood stream and then can be used in respiration in glycolysis to produce ATP for metabolism or it can be stored as glycogen

> Without water, hydrolysis in digestion would not be possible, starch couldn’t be hydrolysed

• Therefore, would be excreted, wouldn’t be able to get the valuable molecules that you need in your bloodstream to be assimilated in the body