CELL STRUCTURE
Tissue - |
A group of cells working together to carry out a specific function |
Organ - |
A group of tissues working together to carry out a specific function out |
Organ System- |
A group of organs working together to carry out a specific function |
Organelles found within animal cells - |
- Nucleus -mitochondria -ribosomes -cell membrane -cytoplasm |
Organelles found within Plant cells - |
-Nucleus -Mitochondria -ribosomes -cell membrane -cytoplasm -permanent vacuole -chloroplasts -cell wall |
CHEMICAL ELEMENTS
lipids |
- C, H, O (Carbon, Hydrogen and Oxygen) |
proteins |
- C, H, O, N, S (Carbon, Hydrogen, Oxygen, Nitrogen and Sulphur) |
complex carbs like starch and glycogen are made up of |
- simple sugars |
Proteins are made up of |
- amino acids |
the two molecules that Lipids are made up of |
- Glycerol and fatty acid tails |
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FUNCTIONS OF THE ORGANELLES
Nucleus |
- controls the cell -contains genetic material (In the form of chromasomes) |
Cytoplasm |
- where most of the chemical reactions take place |
Mitochondria |
- where aerobic respiration takes place |
Ribosomes |
- the site of protein synthesis |
Cell wall |
- provides strength and support (Made out of cellulose) |
Permanent Vacuole |
- supports the cell and contains cell sap (A solution of sugars and salt) |
Chloroplasts |
- the site of photosynthesis |
Cell Membrane |
- controls what enters and leaves the cell - separates the cell from its environment |
ENZYMES
enzymes |
- biological catalysts that increase rate of metabolic reactions |
factors that effect enzyme function |
- Temperature -pH - Substrate concentration -Enzyme concentration |
effect of temperature |
-as temperature increase, rate of reaction increases UNTIL the temperature exceeds the optimum and the rate of reaction begins to decrease |
Why does this happen? |
as temperature increase, particles have more kinetic energy, increasing chance of collision between molecules which speeds up the reaction |
when the temperature exceeds optimum |
- active site distorts as the enzyme denatures and it no longer fits the substrate |
effect of pH |
- the rate of catalysed reaction is fastest at the optimum pH. If the pH is too high or too low, the enzyme may denature and this affects rate of reaction |
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STEM CELLS (HIGHER)
Differentiation |
- the process by which cells become specialised |
Stems cells |
- unspecialised cells that can differentiate into lots of different types of cells |
ADVANTAGES |
-can be used to treat paralysis -possibility to cure degenerative diseases like Parkinson's -Whole new tissues and organs can be grown for drug testing |
DISADVANTAGES |
-use of embryonic cells creates ethical issues -it's expensive -long-term side effects are unknown |
DIFFUSION
diffusion |
- the movement of molecules from an area of high concentration, to an area of low concentration |
how does temperature affect the rate of diffusion |
- as temperature increase, rate of diffusion increases as particles gain kinetic energy and move faster |
how does concentration gradient affect rate of diffusion |
- the greater the concentration gradient (The difference between the two areas), the greater the rate of diffusion |
how does surface area of the membrane affect rate of diffusion |
- as surface area increases, rate of diffusion increases as there is more space for the particles to pass through |
OSMOSIS |
- the movement of water molecules from a high water concentration to a low water concentration (Down the water potential gradient) through a partially permeable membrane. |
ACTIVE TRANSPORT |
- the movement of particles from an area of low concentration to an area of high concentration (Going against the concentration gradient) |
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