Max Lee
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Eukaryotic cell definition and 2 examples
Cells that contain their genetic information enclosed in a nucleus. Animal or plant cells
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Prokaryotic cell definition and 1 example
Cells that dont contain their genetic information enclosed in a nucleus. Bacterial cells
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1 micro meter = ? m (standard form)
1 x 10^-6 m
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1 order of magnitude and 2 orders of magnitude equals ? times bigger
10x bigger than the one before it. 100x
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In a cell, where does chemical reaction take place
Cytoplasm
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Cell membrane
Control molecules that can leave or enter the cell
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Mitochondria
Where aerobic respiration takes place
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Ribosomes
Sites of protein synthesis
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Chloroplasts
Contain chlorophyll and are the sites of photosynthesis
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What does 'plant wall' do
Strengthens the cell
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Permanent vacuole
Filled with cell sap that helps give the cell its shape
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Differentiation
When cells become specialised
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3 animal specialised cells
Sperm, nerve, muscle cells
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Sperm cell role and 2 adaptions
Role is to join with an egg cell, fertilising it. Long tail to swim to the ovum and streamlined to make it easier
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Nerve cell role and 2 adaptions
Role is to send electrical impulses around the body. Long axon to carry impulses , dendrites increase surface area
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Muscle cell role and 2 adaptions
They contract. Also packed full of mitochondria to provide energy to contract.
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3 plant specialised cells
Root hair, Xylem, Phloem cells
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Root hair cells adaptation
Role to absorb water. Covered in hair - increasing surface area to absorb water
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Xylem cells adaptation
Long tubes to carry water and dissolve minerals. Thick walls to provide support the plant.
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Phloem cells adaptation
Carry dissolved sugars up and down the plant, mitochondria to provide energy.
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PRACTICAL microscope
Place the slide onto the stage. Use the clips to hold the slide on place. Select lowest power objective lens, position the lens almost touching the slide by turning the coarse fining dial. Look down through the eyepiece and slowly turn coarse focusing dial to get it to focus. Then use fine focusing dial to bring the cells into a clear focus. Calculate the magnification by eye piece lens (10x) multiplied by objective lens (e.g 4x). REPEAT with higher power objective lens.
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light vs electron microscopes
Light microscope have limited magnification and resolution. Electron microscope much greater magnification and resolution
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Magnification formula
Size of image / Size of real object
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How many chromosomes in humans
46
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Chromosomes
Carry a large number of our genes
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Mitosis
Doubles the internal structures and chromosomes in a cell. They are pulled to opposite sides of the cell and the cell membrane divides to form two identical cells
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Mitosis occurs when :
Organism repairs itself
Asexual reproduction
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Stem cells
Undifferentiated cells which can differentiate to other types of cells.
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2 places stem cells can be found
Bone marrow and embryo
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Diffusion
Spreading out in particles resulting in the net movement from an area of higher concentration to an area of lower concentration
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2 factors affecting diffusion
Higher temp = greater rate of diffusion
Higher concentration gradient = greater rate of diffusion
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Osmosis
Diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane (diffusion for water)
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Active transport
Moves substances from a more dilute solution to a more concentrated solution (opposite of diffusion)
