Additional Biology Notes

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cells, tissues and organs

an animal cell contains:

cell membrane

cytoplasm

nucleus

mitochondria

ribosomes

a plant cell contains:

chloroplast

vaucole

cell wall

cell membrane

mitochondria

nucleus

ribosomes

cytoplasm

structure and function

cell membrane - controls what goes in and out of the cell

cytoplasm - where chemical reactions takes place

nucleus - controls the activity of the cell and contains genetic material 

ribosomes - where protein synthesis takes place

mitochondria - the site of aerobic respiration to break down glucose to create energy

chloroplasts - contain chlorophyll to absorb sunlight for photosynthesis

vaucole - contains cell sap and keeps the cell rigid for support

call wall - made of cellulose to support and strengthen the cell

a bacterial cell contains:

cell membrane 

cell wall

flagella

DNA plasmid

circular DNA

slime capsule 

Specialised cells

a cell containing a small amount of cytoplasm - more space for fat

a cell containing many mitochondria - provides more energy to reform pigment needed to let you see in colour

a cell with large surface area - greater uptake of mineral ions and water

a cell with a fatty myelin sheath - insulates neurone for faster nerve impluses

a cell with no nucleus - more space for haemoglobin to carry oxygen 

Diffusion

diffusion is the spreading out of the particles in a gas or substance in a solution

the movement is from an area of high concentration to an area of low concentration

6 mark question about naming substances that diffuse into animal and plant cells:

animal cells:

during respiration,oxygen is being used and so will diffuse into the cells whilst carbon dioxide is being produced so will diffuse out of cells.

in digestion, glucose, fatty acids and amino acids (the products of digestion) will diffuse from small intestine into the bloodstream

water being absorbed back into the body through the large intestine

plant cells:

in the leaf, carbon dioxide will diffuse into the leaf through stomata whilst oxygen diffuses out. This is the reactant and product of photosynthesis

water being lost in leaves from transpiration 

water being taken in from the soil into the roots

smallest to largest:

CELL - a group of cells make a tissue

TISSUE - a group of tissues make an organ

ORGAN - organs doing the same process makes up an organ system

ORGAN SYSTEM - a process such as digestion 

photosynthesis

the equation for photosynthesis:

carbon dioxide + water -----sunlight------ oxygen + glucose

how do plants use this glucose?

converted into starch for storage

to make oils

to make proteins

energy for respiration

Test for starch is to put iodine on as iodine will go from orange to black in the presence of starch

Use of glucose in plants

plants use glucose in a number of ways such as:

stored or converted into starch which is used as a back up energy source

to make amino acids and proteins

to make fats and oils

respiration

growth and reproduction

the limiting factors of photosynthesis

the effect of light intensity…

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