B4 Mindmap
- Created by: tom1000
- Created on: 14-04-16 17:46
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- B4
- Cell structure and function
- Plant and animal cells have similarities and differences
- Most animal and plant cells have parts
- Nucleus
- Cytoplasm
- Cell membrane
- Mitochondria
- Plant cells also have a few extra things animal cells don't have
- Rigid cell wall
- Made of cellulose, it supports the cell and strengthens it.
- Vacuole
- Contains cell sap, a weak solution of sugar and salts
- Chloroplasts
- where the reactions for photosynthesis take place. Contains chlorophyll and the enzymes needed for photosynthesis
- Rigid cell wall
- Most animal and plant cells have parts
- Bacteria have a simple cell structure
- They don't have a nucleus
- They have a circular molecule of DNA which floats around in the cytoplasm.
- They don't have mitochondria either
- But they can still respire anaerobically
- They don't have a nucleus
- Plant and animal cells have similarities and differences
- Enzymes
- Enzymes are proteins that speed up chemical reactions
- Enzymes are very specific
- A substrate is a molecule that is changed in a reaction
- Every enzyme has an active site, it's where the substrate joins onto the enzyme
- Each enzyme only speeds up one reaction, as it's active site is only specific to one substrate.
- The name for how the enzyme only fits one substrate is called the lock and key model
- Enzymes need the right temperature and pH
- They have to be at a specific temperature and in specific conditions to work at their optimum
- Changing the temperature changes the rate of an enzyme controlled reaction
- if you increase the temperature, activity will increase at first, but after a certain point, the bonds in the enzyme will break and it will denature
- When an enzyme denatures, it's bonds break and so it changes shape so the substrate doesn't fit the active site any more
- All enzymes also have an optimum pH and if that changes too much, it will denature aswell
- Aerobic respiration
- Respiration
- Respiration is a series of chemical reactions that release energy by breaking down large food molecules. it happens in living cell
- The energy released in respiration is used to power some of the chemical reactions that happens in cells, e.g. the reactions involved in;
- Movement - Energy is needed to make muscles contract
- Active transport - This process uses energy to move some substances in and out of cells
- Synthesis of large molecules
- Lots of large molecules (polymers) are made by joining smaller molecules together
- Glucose is joined together to make things like starch and cellulose in plant cells
- In plant cells, animal cells and microorganisms, glucose and nitrogen are joined together to make amino acids. the amino acids are joined together to make proteins
- Aerobic respiration needs a lot of oxygen
- The aerobic basically means 'with oxygen'
- It releases more energy per molecule of glucose than anaerobic respiration
- This type of respiration happens most of the time
- Aerobic respiration happens in animal and plant cells, and microorganisms
- The word and symbol equations for aerobic respiration
- Glucose + oxygen => carbon dioxide + water (+energy released)
- C6 H12 O6 + 6 O2 => 6 CO2 +6 H2O (+energy released)
- Respiration
- Anaerobic respiration
- Doesn't use oxygen
- Takes place in animal and plant cells and some microorganisms when there is very little or no oxygen
- Human cells - when you do really vigorous exercise, your body can't supply enough oxygen to your muscle cells for aerobic respiration so they just respire anaerobically
- Plant cells - if the soil a plant's growing in becomes waterlogged there won't be any oxygen getting to the roots so the root cells will have to respire anaerobically
- Bacterial cells - bacteria can get under your ski n through puncture wounds caused by things like nails. there's very little oxygen there so only the bacteria that can respire anaerobically can survive.
- Energy is always released during anaerobic respiration, but the products of the reactions are different depending on the type of cell it happens in
- Anaerobic respiration can produce lactic acid
- In animal cells and some bacteria anaerobic respiration causes lactic acid
- Anaerobic respiration can also produce ethanol and carbon dioxide
- In plant cells and some microorganisms (like yeast) anaerobic respiration produces ethanol and carbon dioxide
- Fermentation is where microorganisms break down sugars into other products as they respire anaerobically. humans use fermentation to make lots of things like booze, biogas, and bread
- Cell structure and function
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