Biological molecules, Cell structure and Division, Cell membrane and Cells and the Immune system.

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What are polymers?
Polymers are large complex molecules composed on a long chain of monomers joined together.
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What are monomers?
Monomers are small, basic molecular units that together form polymers.
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What is the difference between alpha glucose and beta glucose?
The alpha glucose -OH group is at the bottom whilst the beta glucose -OH group is at the top.
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What defines alpha glucose and beta glucose as having the same molecular structure but connected in a different way?
Isomer
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What bond is formed in a condensation reaction of carbohydrates?
Glycosidic bond
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What is the waste product of a condensation reaction?
Water
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What is condensation?
This is when two molecules join together with the formation of a new chemical bond and a water molecule is released.
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What are the products of hydrolysis of sucrose?
glucose + fructose
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What are the products of hydrolysis of lactose?
glucose + galactose
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What are the products of hydrolysis of maltose?
glucose + glucose
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What is hydrolysis?
A hydrolysis reaction breaks the chemical bond between monomers using a water molecule.
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What is the test for reducing sugars?
1) Add Benedict Reagent (blue) and heat it in a water bath product to boil 2)If the test is positive it will form a brick red coloured precipitate
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What is the test for non-reducing sugars?
1) Test for a reducing sugar 2) If the test is negative add dilute hydrocholic acid 3) Heat in a water bath brought to boil 4) Neutralise with sodium hydrogencarbonate 5) Test again by the reducing sugar test if positive, the test is positive.
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What is starch?
Plants store excess glucose as starch
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What is the structure of starch?
Build up of Amylose and Amylopectin. Amylose - Long, unbranched chains and coiled structure make it compact. Amylopectin - long, branched chain easily broken down. Also, starch is insoluble so it does not affect water potential.
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What is the test for starch?
Just add iodine, if starch is present the sample should change to a blue-black colour.
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What is glycogen?
Animals store excess glucose in Glycogen rather than starch.
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What is the difference between starch and glycogen?
Glycogen is much more branched this is because it's a source of energy storage for animals which need way more energy as they're usually larger.
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What is the structure of Glycogen?
Glycogen has a similar structure to amylopectin except it is much more branched. It's also very compact and insoluble in water.
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What is cellulose?
Cellulose builds up the cell membrane because of its structure.
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What is the structure of cellulose?
Cellulose is long, unbranched chain of beta glucose. When beta-glucose molecules bond they form straigh chains of cellulose, alternate beta glucose are rotated 180 degrees. Cellulose chains are linked together by hydrogen bonds to form strong fibres.
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What is the structure of a triglyceride?
Glycerol + 3 fatty acid
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What are the bonds between glycerol and fatty acids?
Ester bond
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What is the difference between a saturated and unsaturated fatty acid?
Saturated fatty acids do not have a double bond between their carbon atoms. Whilst, unsaturated fatty acids have a double bond between their carbon atoms.
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What is the difference between a phospholipid and tryglyceride?
Phospholipids are similar except one fatty acid is replaced by a phosphate group.
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How do phospholipids make the cell membrane bilayer?
The phosphate group is hydrophylic and the fatty acid is hydrophobic. This means the fatty acid goes inwards the cell away from water whilst the phosphate goes away from the centre toward water forming a two layer bilayer.
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How do we test for lipids?
Shake the substance in ethanol and pour it in water. If a white emulsion forms the test is positive.
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What is the molecular structure of proteins?
H2N - C - R - H - COOH
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What bonds form in the condensation of amino acids?
Peptide bonds
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What is the primary structure of a protein?
The arrangement of amino acids inside the chain.
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What is the secondary structure?
Hydrogen bonds form in the polypeptide chain making it fold into either a beta pleated sheet or an alpha helix.
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What is the tertiary structure?
The chain is often then further folded and coiled. More bonds from between parts of the chain including: Disulfide bonds, hydrogen bonds and ionic bonds.
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What is a disulfide bond?
When the sulfur atoms in one cysteine bond with the sulfur atoms on a different cysteine.
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What is the Quaternary structure?
Some proteins are made of several polypeptide chains bonded together. The Quaternary structure is how these polypeptide join.
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How do we test for proteins?
We add Sodium hydroxide to the solution and copper sulphate. If proteins are present the solution turns purple.
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Difference between the lock and key and induced fit theory?
The induced fit model explains that enzymes change shape to mould around the substrate oppose to the lock and key method where the substrate and enzyme active site are complementary.
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Enzyme properties that relate to the tertiary structure?
Enzymes are very specific they usually catalyse only one reaction, this is because only a complementary active site will fit to the subtrate. The shape of the active site is determined by the tertiary structure.
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What factors affect the rate of reaction?
pH, enzyme concentration, substrate concentration and temperature.
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How does pH affect the active site?
The pH is determined by the amount of H+ and OH- ions found in the acid or alkali. These ions can mess up the ionic bonds in the tertiary structure and change shape of the enzyme.
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How does temperature affect the enzyme?
The greater the temperature, the greater the kinetic energy of molecules. This makes enzyme more likely to collide and form a ESC. Eventually, this will break some of the bonds and denature the enzyme.
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How does the enzyme concentration affect the rate of reaction?
The more enzyme molecules there are in the substrate the more likely the substrate molecules will collide with one and other. Therefore, more chances of ESC forming increasing the ROR. However, when the substrate is limited there will be no change.
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How does the substrate concentration affect the rate of reaction?
The higher the substrate the higher the chance of successful collision increasing the change of enzyme substrate complexes forming until this is inhibited by the amount of enzymes. This decreases as time passes.
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What is competitive inhibition?
Competitive inhibition molecules have similar shape to the other substrate molecules. They compete with the substrate molecules to bind to the active site but no reaction takes place. Instead they block the active site so no molecules can fit it.
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How can competitive inhibition be reduced or increased?
The greater the concentration of competitive enzymes the more enzymes are inhibited, the greater the concentration of substrate the more likely they will collide with the enzymes instead of the substrate inhibitors.
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Non-competitive inhibition
Non-competitive inhibition molecules bind to the enzymes away from the active site. This causes the active site to change shape. So molecules can no longer bind to it.
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What is the use of DNA?
DNA stores the genetic information that all the information a organisms needs to grow and develop.
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What is the use of RNA?
One of the main function of RNA is to transfer genetic information from DNA to the ribesome.
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What is the structure of a DNA nucleotide?
The pentose sugar is deoxyribose, bases are ATCG and phosphate.
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What is the structure of RNA nucleotide?
The pentose sugar is ribose, bases are AUCG and a phosphate group.
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What bonds are formed between nucleotide?
Phosphodiester bonds
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What is the DNA structure?
1) Two polypeptide chains in a double helix 2) Hydrogen bonds between bases 3) ATCG complementary bases 4) Two anti parallel (opposite direction strands).
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Is RNA or DNA shorter?
RNA Is relatively short.
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What is Semi-conservative replication?
It is called this because half of the strand in each new DNA strand is from the original molecule.
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What enzymes are used to unzip the DNA strand?
DNA helicase
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What enzymes are used to catalyse the nucleotide of the new strand?
DNA polymerase
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What did Meselson and Stahl do in their experiment?
Two samples of bacteria were grown one from a sample with light nitrogen and heavy nitrogen. As bacteria reproduced they took up nitrogen from the broth to help make nucleosides.
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What happened in Meselson and Stahl experiment?
When Light nitrogen bacteria was put into the broth with heavy nitrogen the bacteria settled in the middle because it contained one strand of light nitrogen and one start of heavy nitrogen.
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Water is vital for living organisms, give some important properties of water?
1) It is a metabolite in lots of important metabolic reactions. 2) Water is a solvent therefore substances can dissolve in it 3) Helps in temperature control 4) Water molecules are very cohesive
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Why is water being a metabolite important for a living organisms?
Water is needed in metabolic reactions such as condensation and hydrolysis which both either release or need water to break and form bonds.
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Why is water good temperature regulator?
It takes a lot of energy to break the hydrogen bonds between water. So water has a high latent heat of vaporisation, therefore a lot of energy is used in evaporation. This means the body can loose a lot of energy in sweating to cool down the body.
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What is the use of water being a good buffer of temperature?
The hydrogen bonds between water molecules can absorb a lot of energy. So water has a high specific heat capacity this is useful in living organisms as it means they do not experience rapid temperature changes.
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What is the use of water as a good solvent?
A lot of substances like ions in metabolic reactions are dissolved. This is because ionic substances have a positive and negative charge which attracts to part of water as its polar. This helps it transport ions around the body.
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Why is it useful for water to have a lot of cohesion?
Water molecules have a lot of cohesion therefore they tend to attract each other. This gives it it's flow which is useful in the xylem for transporting substances.
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What is the structure of ATP?
Made up of the nucleotide base adenine, a ribose sugar and phosphate groups.
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What is ATP?
ATP is a immediate source of energy usually made in the mitochondria in respiration.
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How is ATP produced?
In a condensation reaction with ADP and PI catalysed by the enzyme ATP synthase.
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How is energy released from ATP.
ATP is hydrolysed breaking down phosphate groups in the ATP which stored a lot of energy which is released. This is catalysed by the enzyme ATP hydrolyse.
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Why is ATP a good energy storage source?
It is immediate and controllable source of energy.
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What can ATP also do?
Inorganic phosphate can also be put to use by adding it to another compound which often makes it more reactive.
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What are Eukaryotic cells?
An organisms whose cells contain a nucleus surrounded by a membrane and whose DNA is bound together by histones.
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What are Prokaryotic cells?
A simple, single-celled organism that lacks a nucleus and membrane-bound organelle.
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What is the structure of the cell membrane?
Made mainly of lipids and proteins. It is found on the surface of animals cells and just inside the cell wall.
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What is the function of the cell membrane?
Regulates the movement of substances into and out of the cell.
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What is the structure of a nucleus?
A large organelle surrounded by a nuclear envelope which contains many pores. The nucleus contains many chromosomes.
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What is the function of the nucleus?
The nucleus controls the cell's activities by controlling transcription.
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What is the structure of the mitochondria?
Usually oval-shaped organelle with a double membrane - the inner one is folded to form Cristina inside the matrix.
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What is the function of the Mitochondria?
This is the site of aerobic respiration where ATP is produced. in other words it releases energy.
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What is the structure of a chloroplast?
A small flattened structure found in plants surrounded by a double membrane. And a membrane inside called the thykloid membrane. These membranes are stacked up in some parts of the chloroplast to form grana, grana are linked by lumallae.
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What is the function of a chloroplast?
The site where photosynthesis takes place.
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What is the structure of the Golgi Apparatus?
A group of fluid-filled-membrane-bound fluid sacs, vesicles are often found on the edges of sacs.
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What is the function of the Golgi Apparatus?
It processes and packages new lipids and proteins.
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What is the structure of the Golgi vesicle?
A small fluid-filled sac in a cytoplasm surrounded by a membrane produced by the Golgi Apparatus.
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What is the function of the Golgi vescile?
Contains digestive enzymes called lysozymes. These digest and break down invading cells or worn out components.
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What is the function of the ribesome?
This is were proteins synthesis occurs.
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What is the structure of the EPR?
A system of membranes enclosing a fluid-filled space. The surface is covered with ribesomes.
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What is the function of the EPR?
Folds and processes proteins that have been made at the ribesome.
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What is the function of the SER?
Synthesises and processes lipids.
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What is tissue?
A group of specialised cells working together for a particular function.
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What are organs?
A group of different tissues.
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What is the cell wall of bacteria from?
Murein
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What do prokaryotic cells replicate by?
They replicate by binary fission - the cell replicates and then splits into two daughter cells.
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What is the formulae for Magnification?
Size of image/Size of real object
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What is the difference between a light and electron microscope?
Light microscopes use light to form a image, they're usually have a lower resolution, and much lower magnification. Electron microscopes are more likely to produce artefacts, much more expensive, complex setting process and must be in a vacuum.
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Difference between scanning and transmission electron?
Scanning microscopes scan a beam of electrons along the surface to form a 3D image which can use a think specimen.On the other hand, TEM are 2D and can not be used on thick specimen.
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How to make a temporary mount?
1) Pipette a drop of liquid on the slide 2) Suspend a thin section of the specimen inside the drop of water 3) Add a drop of stain 4) Finally, add the cover slip.
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Why must the specimen in a light microscope be thin?
So that light can pass through the object and be viewed.
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In what condition does homogenate have to be?
Isotonic - Same concentration of chemicals inside the cell as on outside, ice-cold - to prevent activity of digestive enzymes and a buffer solution must be used to maintain pH.
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Give the steps of cell fractionation:
1) Break the cell wall and cell membrane 2) Filter the cellular depris 3) Spin at different speeds to obtain organelles based on how dense they're.
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Name the stages of mitosis:
Interphase, Prophase, Metaphase, Anaphase and then Telophase.
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What occurs in Interphase?
This consists of three stages; G1 stage - cell grows new organelles and proteins are produced, S stage - Cell replicates its DNA and G2 stage - the cell continues to grow
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What occurs in Prophase?
The chromosomes condense getting shorter and fatter. Tiny centrioles start moving toward the end of the cell. The membrane around the nucleus starts to break.
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What occurs in Metaphase?
The chromosomes line up in the centre of the cell and become attatched to the spindle by the centromere.
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What occurs in Anaphase?
The centromere divides, separating each pair of sister chromatin. The spindle pull each of the sister chromatin to the opposite ends of the cell.
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What happens in telophase?
The chromatids reach the opposite poles on the spindle they uncoil and become long and thing again. A nuclear envelope forms around them. The cell divides (cytokineses) two identically similar cells form.
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Why do some cancer drugs target the mitosis stage?
To prevent the cells from replicating and spreading the cancer.
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What is meant by the fluid mosaic structure of the cell membrane?
Fluid mosaic model describe how the cell membrane is "fluid" because the phospholips are constantly moving. And, the "mosaic" describes how the proteins are scattered through the bilayer like the tiles in a mosaic.
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What is the job of cholesterol in the phosholipid?
The cholesterol fit between the phospholipids, They bind to the hydrophobic causing them to pack more closely. This helps maintain the shape of the cells.
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What happens in the conditions of 0 degrees in the cell membrane?
The phospholipids don't have much energy. As a result, they stay virtually still and don't move around often. This makes them not as permeable but channel proteins and carrier proteins deform increasing the permeability of the cell membrane.
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What happens in the condition of 0 to 45 degrees in the cell membrane?
The phospholipids can move around and aren't packed as tightly together making the membrane more permeable. This makes the membrane partially permeable.
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What happens in the conditions of above 45 degrees in the cell membrane?
The phoshpholipid bilayer starts to melt and hte membrane becomes more permeable. Channel proteins and carrier proteins deform so they can't control the permeability either. Water levels inside the cell increase the the cell could burst.
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What is diffusion?
Diffusion is the net movement of particles from a area of high concentration to a area of low concentration. This is a passive process so no energy is required.
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What is facilitated diffusion?
Facilitated diffusion is the same as diffusion but using a protein channel or carrier.
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What factors effect simple diffusion?
1) The concentration gradient - the higher it is, the faster the rate of diffusion. 2) The thickness of the exchange surface. 3) The surface area.
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What factors effect Facilitated diffusion?
1) The concentration gradient - the higher the faster 2) The number of channel and carrier proteins
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What do channel proteins transport?
They transport charged particles by making pores in the membrane for them to diffuse through.
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What do carrier proteins transport?
The carrier proteins move large molecules across the membrane down their concentration gradient. When the molecule is attached to the carrier protein, the protein changes shape and releases the molecule at the opposite side of the membrane.
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What is osmosis?
Osmosis is the diffusion of molecules across a partially permeable surface, from a area of high water potential to a area of low water potential.
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What factors affect water potential?
1) The water potential gradient 2) The thickness of the exchange surface 3) The surface area.
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What is active transport?
Active transport is the movement is the movement of molecules and ions against the concentration gradient using energy. It also like facilitated diffusion requires channel and carrier proteins.
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What is an antigen?
A antigen is a molecule usually protein that generates a immune response when detected by the body.
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Name the stages of the immune system response
1) Phagocytes engulf pathogen 2) Phagocytes activate T-Cells 3) B-Cells activate T-Cells which divide into plasma cells 4) Plasma cells make more antibodies to a specific antigen.
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Describe the process of phagocytosis
Phagocytes find foreign antigen on the pathogen, the phagocyte moves around the pathogen engulfing it, the pathogen is now contained in the phagocyte vacuole. A lysosomes fuses with this vacuole subjecting it to digestive enzymes that break it down.
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Why are antibodies specific?
Antibodies are proteins, they're made up of amino acids and the shape is determined by the tertiary structure complementary to the specific antigen. This helps form a antibody-antigen complex.
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What is the primary immune response?
This is when an antigen enters the body for the first time and activates the immune response. It is slow as there are not enough B-Cells. Meanwhile, it takes for the immune system to produce enough antibodies the user experiences symptoms.
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What is the secondary immune response?
If the same pathogen enters the body again, the immune system will produce a quicker, stronger immune response. Clonal selection happens fast, memory B-Cells are activated and divided into plasma cells and T-Cell production is also much quicker.
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What are vaccines?
Vaccine is a way of becoming immune to a disease by injecting a dead or inactive version of the pathogen into your bloodstream for you're body immune system to create memory cells against it.
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What is antigenic variation?
Some antigen can change their surface antigens this means when you're infected for the second time the antigen is not recognised and the immune system has to start from scratch.
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What is active immunity?
This is a type of immunity when your immune system makes its own antibodies after being stimulated by an antigen.
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What is passive immunity?
This is a type of immunity you get from being given antibodies from a different organism.
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What are the differences between active and passive transport?
Active transport produces memory cells, Passive transport does not. Active transport protection is long-term, whilst for passive immunity it's not.Also, no antigen is needed for passive immunity and production is immediate oppose to Active transport.
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What are monoclonal antibodies?
These are antibodies produced from a single group of genetically identical B-Cells. Therefore, the binding site for the antibodies is specific for each of these antibodies.
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How can monoclonal antibodies be used to treat cancer?
Cancer has unique antigens that monoclonal antibodies can bind to. The monoclonal antibodies can be traced with cancer killing drugs that upon binding with the cancer antigen will destroy it. This is useful as only cancer cells are destroyed.
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What is the difference between direct ELISA and indirect ELISA?
Primary antibody binds to antigen trapped at the bottom of well, secondary antibody with enzyme binds to this antibody. Then was it all to remove excess antibodies. When a solution is added the substrat reacts with enzyme to form a coloured solution.
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What is HIV structure?
HIV has a core that contains the genetic material (RNA) and some proteins including enzyme invertase, an outer coating called capsid and an extra outer layer called an envelope.
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Why do antibiotics not work on viruses?
Bacteria use their own bacterial enzymes and ribesomes which antibiotics can target. However, in viruses case they use the host enzymes and ribesomes which antibiotics do not target because they don't target the hosts processes.
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What are the bonds between phosphate and two ester bonds?
Phosphodiester bonds
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What does HIV stand for?
Human immunodeficiency virus
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What does HIV do?
HIV kills T-Helper cells, without them the immune system can not mount to a effective immune response. This will lead to the immune system deteriorating and people being more vulnerable to disease.
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Card 4

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What defines alpha glucose and beta glucose as having the same molecular structure but connected in a different way?

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Card 5

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What bond is formed in a condensation reaction of carbohydrates?

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