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Biology Topic 1 Cell Biology - Coggle Diagram
Biology Topic 1 Cell Biology
Prokaryotes Simpler Cells
Bacteria
Cell membrane- site of chemical reactions. Gel like substance containing enzymes to catalyse the reactions.
Bacteria DNA- not in the nucleus as it floats in the cytoplasm. Controls the function of the cell.
Cell wall- Not made of cellulose. Supports and strengthens the cell.
Cytoplasm- semi permeable. Controls the movement of substances in and out the cell.
Plasmids- Small rings of DNA. Contain additional genes.
Eukaryotes Complex Cells
Animal
Cytoplasm- Site of chemical reactions. gel like substance containing enzymes to catalyse reactions.
Nucleus- contains genetic materials. Controls the activities of the cell and codes from proteins.
Cell membrane- semi permeable. Controls the movement in and out the cell.
Ribosome- Site of protein synthesis.
Mitochondria- Site of respiration. Where energy is released for the cell to function.
Plant
Permanent vacuole- contains cell sap. Contains sugars and fats.
Cell wall- Made of cellulose. Supports and strengthens the cell,
Chloroplast- site of photosynthesis. Contains chlorophyll and absorbs light energy.
Magnification
Magnification M = Size of Image I / Real size of the object A
Specialised Cells
Plant
Root hair
absorb water and minerals from the soil. Have hair like projections to increase surface area.
Xylem
Carry water and minerals. TRANSPIRATION. Only flows in one direction.
Phloem
Carries glucose. TRANSLOCATION. Can carry in both directions.
Animal
Nerve
carries electrical signals. Long branched connections and insulating sheath.
Sperm
Fertilise an egg. Streamlined with a long tail, contain many mitochondria.
Muscle
contract to make movement. Contains a large number of mitochondria. Long
Transport in Cells
Diffusion
Requires no energy. Movement of particles in a solution or gas from a high concentration to a low concentration.
Osmosis
Requires no energy. Movement of particles in a liquid from a low concentration to a higher.
Active Transport
Requires energy. Movement of particles from a dilute solution to a concentrated solution.
Cell Differentiation
Animal
Early stages of development only for repair and replacement.
Plant
All stages of the life cycle. cells are grouped together in meristems.
Undefferentiated Cells
Called
STEM
cells
Human Embryonic Stem Cells
can be cloned and differentiated into most cells. Therapeutic cloning is using the same gene so the body doesn't reject the cell.
Adult Bone Marrow Stem Cells
Can form many types of human cells e.g. blood cells. Tissue is matched to avoid rejection.
Meristems (plants)
Can differentiate into a plant cell. Used to produce clones quickly and economically.
Mitosis and the Cell Cycle
Cells divide in a series of stages.
Stage 1:
Growth
- Increase the number of sub-cellular structures. e.g. ribosomes, mitochondria
Stage 2:
DNA Synthesis
- DNA replicates to form two of each chromosome.
Stage 3:
Mitosis
- One set of chromosomes is pulled to either end of the cell and the nucleus divides. The cytoplasm and cell membranes divide to form two identical cells.