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B1 - Mocks - Coggle Diagram
B1 - Mocks
L5 - Specialised Cells
Sperm cells contain acrosome in their heads (this substance contains enzymes), contain mitochondria to provide energy for movement and have flagellum for swimming.
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Muscle cells contain filaments of protein that can slide over each other to cause muscle contraction, they also contain many mitochondria to aid with movement.
Root hair cells have thin walls to not restrict the movement of water and have a large surface area.
The xylem lacks certain walls so that a continuous column can be formed, lignin strengthens the cells.
The phloem is accompanied by companion cells which provide the phloem with the energy required to transport substances.
L3 - Microscopes
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Light Microscope:
Pros: Cheap, portable, accessible, little preparation needed.
Cons: Limited magnification and resolution (x1500, 200nm)
Electron Microscope:
Pros: Massive magnification and resolution.
Cons: Expensive and difficult to set up and maintain.
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L9/10 - Stem cells
Embryonic stem cells can differentiate into any type of cell but there are ethical concerns surrounding their use.
Adult stem cells (extracted from bone marrow) can only differentiate into a set number of cell types.
In plants, stem cells are located in the meristem.
Therapeutic cloning is a process in which embryonic cells are created containing the genetic material of the patient.
Stem cells could be used to replace nerve cells of paralysed patients or the insulin-producing cells in people with diabetes.
L6 - Differentiation
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In mature animals, the role of cell differentiation is simply repair and replacement. When a cell differentiates, it acquires different sub-cellular structures to enable it to carry out a function.
L8 - The Cell Cycle
1) Before a cell divides, the DNA within the cell replicates, the cell grows bigger, more organelles are made.
2) Mitosis occurs; one copy of each chromosome is created and they move to opposite sides of the cell.
3) Division occurs; the cytoplasm and cell membrane divide and the cell becomes two identical daughter cells.
L1 - Cell Structure
Animal Cells:
- Nucleus - Controls activities of the cell; stores genetic information.
- Cytoplasm - Most of the cell's chemical reactions occur here.
- Cell membrane - Controls the movement of substances in and out of the cell.
- Mitochondria - Aerobic respiration takes place here.
- Ribosomes - Synthesise protein molecules (used for cell growth).
Plant Cells:
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- Chloroplasts - Contain chlorophyll, the pigment that absorbs sunlight for photosynthesis.
- Vacuole - Contains cell sap.
- Cell wall - Cellulose wall that ensures that the cell is rigid and strong.
L2 - Pro and Eukaryotes
Plant and animal cells are eukaryotic, they contain a membrane bound nucleus.
Bacterial cells are prokaryotic. Within these cells, genetic information is stored in a single loop and in small loops known as plasmids.
L7 - Chromosomes
The nucleus of a cell contains chromosomes, these chromosomes contain a large number of genes. They are typically found in pairs.
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L11 - Diffusion
Diffusion is the passive net movement of particles from an area of high to low concentration (down the concentration gradient), this does not require energy.
Examples of diffusion in the body include: oxygen and carbon dioxide in gas exchange and the urea from cells into the blood plasma.
L12 - Rate of diffusion
To increase the rate of diffusion: increase the steepness of the concentration gradient, increasing the temperature, increasing the surface area of the diffusion surface