Biological molecules (Mindmap 1)
- Created by: LaurenSkyeShelley
- Created on: 30-04-17 09:27
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- Biological Molecules
- Biological molecules are particular groups of chemicals that are found in organisms
- Bonding and formation of molecules
- Covalent Bonding
- Atoms share a pair of electrons in their outer shells
- Ionic Bonding
- Ions with an opposite charge attract one another, this electrostatic attraction is known as an ionic bond
- Hydrogen Bonding
- The electrons within a molecule are not even distributed but tend to spend more time at one position
- This region is more negatively charged
- The molecule is polarised/ is a polar molecule
- This region is more negatively charged
- The electrons within a molecule are not even distributed but tend to spend more time at one position
- Covalent Bonding
- Polymerisation & formation of macromolecules
- Monomers linked together to form long chains
- These are called polymers and the process by which they are formed is called polymerisation
- Monomers linked together to form long chains
- Condensation and hydrolysis reactions
- In the formation of polymers by polymerisation, each time a new sub unit is attached a molecule of water is formed
- Reactions that produce water are condensation reactions
- Examples: formation of polypeptides from amino acids & formation of the polysaccharide starch from monosaccharide glucose
- Polymers can be broken down through the addition of water.
- Water is used to break the bonds that link the sub-units of a polymer, splitting the molecule into its constituent parts
- This is a hydrolysis reaction
- Water is used to break the bonds that link the sub-units of a polymer, splitting the molecule into its constituent parts
- Reactions that produce water are condensation reactions
- In the formation of polymers by polymerisation, each time a new sub unit is attached a molecule of water is formed
- Metabolism
- All the chemical processes in an organism are collectively called metabolism
- Mole and molar solution
- Mole is the unit for measuring the amount of a substance
- One mole contains 6.022 * 10^23 = avogadro's constant
- A molar solution is a solution that contains one mole of solute in each litre of solution
- Mole is the unit for measuring the amount of a substance
- Carbohydrates
- They are carbon molecules combined with water
- Carbon very readily forms bonds with other carbon atoms allowing a sequence of carbons to be built at various lengths
- These form a backbone along which other atoms can be attached permitting a large number of different types of molecule
- The variety of life on earth is because of organisms being based on the carbon atom
- These form a backbone along which other atoms can be attached permitting a large number of different types of molecule
- Carbon very readily forms bonds with other carbon atoms allowing a sequence of carbons to be built at various lengths
- The making of large molecules
- In carbohydrates, the basic monomer unit is a sugar, A.K.A a saccharide
- A single monomer is called a monosaccharide
- A pair of monosaccharides combine to form a disaccharide or an even larger combination would be a polysaccharide
- Examples of disaccharides
- Glucose + glucose = maltose
- Glucose + fructose = sucrose
- Glucose + galactose= lactose
- When monosaccharides join, a molecule of water is removed so it is a condensation reaction
- The bond formed is called glycosidic bond.
- Some disaccharides are reducing sugars so we use the benedict's test
- Some disaccharides are non reducing sugars so we use Benedict's test but it won't change colour so instead it is as follows: add sample to HCl acid and pace test tube in hot bath , add sodium hydrogencarbonate and test with pH paper that the solution is alkaline, re test by using benedict's and it should turn orange/brown
- Starch is polysaccharide
- Test for starch: change colour of iodine in potassium iodine solution from yellow, t blue/black
- Starch is made up of chains of a-glucose monosaccharides
- The chains may be branched or unbranched
- The main role of starch is energy storage
- It is suited to this because:
- It is insoluble and therefore dosen't affect water potential, so water is not drawn into the cells by osmosis
- Being large and insoluble, it does not diffuse out of cells
- It is compact, so a lot of it can be stored in a small space
- When hydrolysed it forms a-glucose which is easily transported and readily used in respiration
- The branched form has many ends, which each can be acted on by enzymes simultaneously meaning that glucose monomers are released rapidly
- It is suited to this because:
- It is never found in animal cells. Instead a similar polysaccharide called glycogen serves as the same
- Glycogen has a very similar structure to starch but has shorter chains and is highly branched
- Its main role is carbohydrate storage.
- It is suited to this purpose because:
- It is insoluble so does not draw water into cells by osmosis
- Insoluble so does not diffuse out of cells
- It is compact so lot can be stored in a small space
- It is highly branched so has more ends that can be acted on simultaneously by enzymes so it is more rapidly broken down to form glucose monomers which are used in respiration
- It is suited to this purpose because:
- Its main role is carbohydrate storage.
- Glycogen has a very similar structure to starch but has shorter chains and is highly branched
- Cellulose is a polysaccharide
- It differs from starch and glycogen because it is made of Beta-glucose monomers rather than Alpha
- This difference causes a difference in structure and function
- Rather than forming a coled chain, cellulose has a straight unbranched chain that run parallel to one another allowing hydrogen bonds to form cross-linkages between adjacent chains allowing there to be strength
- This difference causes a difference in structure and function
- Cellulose molecules are grouped together to form microfibrils which form fibers
- It provides rigidity to a plant
- It differs from starch and glycogen because it is made of Beta-glucose monomers rather than Alpha
- Examples of disaccharides
- A pair of monosaccharides combine to form a disaccharide or an even larger combination would be a polysaccharide
- A single monomer is called a monosaccharide
- In carbohydrates, the basic monomer unit is a sugar, A.K.A a saccharide
- They are carbon molecules combined with water
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