Specialised Cells – Adapted for a specific job
eg sperm, red blood cells, neurones
Nucleus
Cell Membrane
Cytoplasm
Ribosomes
Mitochondria
Cell Wall
Vacuole
Chloroplast
Nucleus – controls cell activity and carries
genetic information
Cell Membrane–controls movement in/out of cell
Cytoplasm – where reactions take place
Ribosomes – where protein syntheses occur
Mitochondria – where most respiration and
energy release occurs
Chloroplast – contain chlorophyll to trap sun
energy for photosynthesis
Vacuole – storage of cell sap
DIFFUSION – passive movement of
molecules from area of high concentration
High
Low
to low concentration across a semipermeable membrane
Eg movement of oxygen from lungs to blood
The greater the difference in
concentration, the faster diffusion occurs
Plant Cell
C
Chemical Reactions – occur in Cytoplasm – controlled by ENZYMES
= Biological Catalyst (speed up chemical reactions eg respiration, protein synthesis, photosynthesis)
- Long chain of amino acids folded into specific shape and denatured above 42°C and work best at specific pH
- Digestive enzymes
–Protease (stomach, pancreas, small intestine) convert proteins to amino acids
-Lipase (pancreas, small intestine) convert fats to fatty acids and glycerol
-Carbohydrase eg amylase (saliva) convert starch to sugars
Stomach produces HCl to make
Industrial uses – Baby foods contains proteases to ‘pre-digest’ food
stomach acidic for enzymes.
- Isomerases convert glucose to fructose which is sweeter so smaller amounts needed
Liver then makes bile to
so used in slimming products
neutralise acid so enzymes in
- Carbohydrases used to convert starch to sugar syrup
small intestine can work
- Proteases and Lipases in biological detergents to break down dirt
Animal Cell
Photosynthesis
-Limited by temp,
CO2, and light
sunlight
Carbon + Water
Dioxide
Glucose + Oxygen
chlorophyll
Storage as
Starch
Energy Losses in Food Chains
Sun
Plant
For respiration
Energy is lost at each stage due to
Rabbit
Fox
So farmers can keep costs to minimum by controlling
environment of farm animals eg keep warm, restrict
movement etc
respiration, heat, movement and waste
Inheritance
Homeostasis
faeces, urine, gas
83kJ
Respiration
Wood/fossil fuels
Die / Decompose
Microbes in warm, O2 rich conditions, break down material
Testes / Ovaries – produce gametes with half chromosomes (by meiosis) which fuse and then divide by
mitosis to form embryo
Sperm and
Embryo
Eagle
Foxes
Rabbits
Grass
8Kg
13Kg
15Kg
20Kg
Pyramid of Biomass – material and energy lost at
each stage
Membrane
Body cell – contain 23 pairs of chromosome (1 of each pair from each parent)– each chromosomes contains
genes = 1 or more genes code for a characteristic. Different forms of the same gene = Alleles
Photosynthesis
Respiration
Semi-Permeable
Blood sugar level – monitored by pancreas
- too much sugar? Pancreas releases INSULIN – converts glucose to glycogen
- if body cannot produce insulin/enough insulin = Diabetes
CO2
Combustion
Low
Concentration
To maintain a constant internal environment
Eg. Removal of wastes – CO2 (via lungs) and urea (via kidneys)
Eg. Maintaining temperature, blood sugar levels, water and ions
Temperature– monitored by thermoregulatory centre of brain, and skin receptors-too hot? – Vasodilation (blood capillaries widen) and sweating – evaporation
of sweat requires heat
- too cold? – Vasodilation (blood capillaries constrict) and shivering – muscle
contractions require energy and release some heat
respiration 13kJ
eat
100kJ
tissues 4kJ
Cycling of Materials
eg Carbon Cycle
Special type of diffusion = OSMOSIS
= the movement of water molecules from a dilute
solution to a more concentrated solution
Eg movement of water into/out of cells
Biology B2
-Need minerals for
Need minerals for healthy growth
healthy growth
Nitrogen
–to make amino acids to form proteins for growth – deficiency = stunted growth
Nitrogen – for growth
Magnesium –for chlorophyll – deficiency = yellow plant
High
Concentration
These cells are called STEM CELLS and can be made to differentiate into many
different types of cells (only possible from stem cells and bone marrow cells)
and can be used in treatment of certain conditions
Bb x Bb
Dominant allele – only 1 needed for gene to be expressed
(B=brown eyes, b=blue)
Recessive allele – both genes needed for expression
B
b
Inherited disease
Cystic Fibrosis – caused by recessive allele – both alleles
B
BB
Bb
needed for disease expression. If 1 allele present =
Brown Brown
carrier
Huntingtons Disease – caused by dominant allele – only 1
b
Bb
bb
allele for the
Brown Blue
disease is needed for the child to express the disease