Structure and functions in living organisms

Elements present in carbohydrates

Carbon, Hydrogen, Oxygen

Elements present in protein

Carbon, Hydrogen, Oxygen and Nitrogen (also may contain sulphur/phosphorus)

Elements present in lipids

Carbon, Hydrogen, Oxygen (may also contain phosphorus/nitrogen)

Nucelus function

membrane-bound organelle that contains genetic material (DNA) and controls the cell’s activities

cytoplasm function

where chemical reactions take place

cell membrane function

a thin barrier that can control which substances enter and leave the cell

cellulose cell wall function

the rigid outer layer of a plant cell that supports it

what is a cellulose cell wall made of?

a strong carbohydrate formed from long chains of glucose molecules

what is the importance of cell differentiation in the development of specialised cells?

allows a zygote to develop into a multicellular organism that each perform different functions

what would happen if we didn’t have cell differentiation?

all cells would be the same, and the organism could not perform specialized tasks essential for life

advantages of using stem cells for medicine

-potential to replace damaged tissues/cells
-can treat a wide variety of conditions eg autoimmune diseases

disadvantages of using stem cells for medicine

-ethical issues
-cost and accessibility
-threat of tumours developing after transplantation

structure of carbohydrates

starch and glycogen from simple sugars

structure of proteins

long chains of amino acids

structure of lipids

made of glycerol and fatty acids

how does temperature affect enzyme function?

increased temperature—>

higher kinetic energy

more collisions

rate of reaction hits peak

why is it bad if the temperature is too high for the enzymes?

excessive heat breaks weak bonds holding enzymes structure

—> causes it to dentature

how can enzyme function be affected by changes in pH?

it alters the active-site which is important for binding to substrate

—> decreases rate of reaction

diffusion definition

the net movement of particles moving from an area of high concentration to low concentration (down the concentration gradient)

how does surface area: volume affect the rate of osmosis?

higher surface area to volume ratio—>more efficient rate of osmosis because there is more membrane area for water molecules to pass through relative to the cell’s volume

chemical symbol equation for photosynthesis

6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂

word equation for photosynthesis

carbon dioxide + water + light energy —> glucose + oxygen

how does varying carbon dioxide concentration/light intensity affect the rate of photosynthesis?

CO₂ /light is a reactant

increasing it—> increase rate of photosynthesis

too much—> it will plateau as other factors become limiting factors

how does temperature affect the rate of photosynthesis?

low temp- enzyme activity slows
rising temp- enzyme and substrate molecules collide more
too high- (above 40) decreased rate enzymes denature- lose shape and cannot function

what does CORMMSS stand for?

Change

Organism

Repeat

Measurement₁

Measurement₂ 

Same₁

Same₂

What chemical is needed to test for the presence of glucose?

Benedicts

What chemical is needed to test for the presence of starch?

Iodine

What chemical is needed to test for the presence of protein?

Biuret

What chemical is needed to test for the presence of fats?

Ethanol emulsion

How to perform glucose experiment?

Add some benedicts solution to food sample

Heat 75°C for several minutes in a boiling water bath

Observe colour change

Colours of benedict test

Brick-red— High concentration

Orange— Moderate concentration

Yellow— Low concentration

Green— Traceable concentration

Blue— No reducing sugars

How to perform iodine test?

Add a few drops of iodine to food sample

If in test tube, gently shake

Observe colour change

Colours of iodine test

Yellow/Brown— No starch

Blue/Black— Starch present

How to perform protein test?

Add a few drops of biuret to food sample

Shake well 

Observe colour change

Colours for protein test

Blue— No protein present

Purple/Lilac— Protein Present

How to perform ethanol emulsion test?

Add a few drops of ethanol to food sample

Mix with water

Observe for emulsion formed

How to know if lipids are present in ethanol test?

Colourless- No fats present

Cloudy/milky white emulsion- Fats present

What is a biological catalyst?

a substance that speeds up the rate of a chemical reaction without being consumed or changed by it

What is an enzyme

a biological catalyst, which is a protein that speeds up the rate of a chemical reaction within the body without being used up in the process

What is the role of enzymes as biological catalysts in metabolic reactions?

They speed up metabolic reactions by lowering their activation energy, allowing essential processes to occur at biologically relevant rates

How can temperature affect enzyme function?

It increases enzyme activity to an optimal point- boosts reaction rates- more frequent collisions

Beyond optimum- Enzyme denatures, loses shape & function- causes reaction rate to plummet

Osmosis definition

The movement of water particles from an area of higher water potential to an area of low water potential down the water potential gradient