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Biology B1 - Coggle Diagram
Biology B1
Microscopes
Units for microscopy:
1km = 1000m
1m = 100cm/1000mm
1cm = 10mm
1mm = 1000 micrometres
1 micrometre = 1000 nanometres
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- The first light microscopes developed in the 1600s and have improved since
- Light microscopes are capable of magnification of up to 2000x
- Electron microscopes were invented in the 1930s and have a much higher magnification of x2,000,000
- Transmission electron microscopes provide detailed 2D images
- Scanning electron microscopes provide 3D, less detailed + black and white image
- Electron microscopes must be left in special conditions
Diffusion, Osmosis and Active Transport
Diffusion is the spreading out of gas or particles in an environment or solution
- Diffusion occurs naturally as particles collide
- Diffusion is affected by concentration gradient, temperature and net movement
- In animals diffusion is involved in movement of sugars across a cell membrane or respiration
Osmosis is the movement of water through a partially permeable membrane
- A dilute solution of sugar contains a high conc of water and low conc of sugar
- A concentrated solution would be the opposite
- If a cell has the same concentration in and out the cell it is isotonic
- More concentration of solute outside a cell makes a cell hypotonic, the opposite is hypertonic
Active transport is the process which uses energy to move substance in a solution against a concentration gradient, from low conc to high conc
- This allows cells to absorb from very dilute solutions
- It is used in plants to absorb mineral ions from soil
- It is used to move glucose from the gut to the blood
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Specialisation In Cells
Human/animal
Nerve cells are specialised to carry impulses around the body, adaptations include:
- Lots of dendrites to connect to other cells
- An axon that carries an impulse from one place to another
- The nerve endings or synapses are specialised to pass impulses to another cells or between a nerve and muscle cell
- Lots of mitochondria to provide enough energy
Muscle cells are adapted to provide movement through contracting and relaxing:
- They contain special proteins that slide over each other making the muscle contract
- They contain many mitochondria to transfer energy needed
- They can store glycogen for energy when contracting
Sperm cells are cells released by the male during sexual reproduction, adaptations include:
- A long tail for movement
- Mid-section full of mitochondria for energy
- front of head contains digestive enzymes to enter egg
- Large nucleus of DNA
Plant
Plant cells are also specialised for certain purposes such as root hair cells:
- Massive surface area
- Large vacuole speeds up osmosis
- Lots of mitochondria
Photosynthetic cells are where plants produce energy, adaptations include:
- Large quantity of chloroplasts
- Positioned in continuous layers
- Large vacuole keeps stability during osmosis
Xylem cells form tubes to carry water and minerals from roots to leaves
- Dead cells form hollow tubes
- Structure of dead cells makes xylem very strong and help support the stem and tubes
Phloem cells transport food made by photosynthesis around a plant
- Cell wall breaks down between cells to form sieve plates which allow movement of water
- Companion sustain phloem with mitochondria