1.1 - Chemical Elements and Biological Compounds Flashcards
What is meant by ‘organic’?
Molecules that have high proportion of carbon atoms.
What is meant by ‘inorganic’?
A molecule or ion that has no more than one carbon atom.
What are 3 functions of inorganic ions?
- muscle contractions
- nervous coordination
- maintaining water potential
What is magnesium like as an inorganic compound?
- mg2+ is a contituent of chlorophyll (photosynthesis)
- chlorosis is lack of chlorophyll (leaves turn yellow)
- mammels need magnesium for growth and repair
What is iron like as an inorganic compound?
- consitituent of haemoglobin (transports oxygen in red blood cells)
- anaemia is the lack of iron in the human diet
What are phosphate ions like as inorganic ions?
- used for making nucleotides like ATP
- constituent of phospholipids, found in biological membranes
What is calcium like as an inorganic ion?
- structural component of bones and teeth in mammels
- component of plant cell walls, providing strength
Why are water molecules dipole?
Positively charged hydrogen and negatively charged oxygen
What bonds form between water molecules?
Hydrogen bonds which are very weak but a very large number of them present makes them difficult to break.
Name the 8 properties of water.
- Water is a metabolite
- High specific heat capacity
- High latent heat of vaporisation
- cohesion
-high surface tension - high density
- water is transparent
What are carbohydrates made out of?
Organic compounds containing carbon, hydrogen and oxygen.
What is one unit of carbohydrate called?
Monosaccharide
What is 2 units of carbohydrates called?
Disaccharide
What are many units of monosaccharides called?
Polysaccharide
What is the formula for monosaccharides?
(CH20)n
n being number of carbon molecules
The name of 3 carbon atoms in a monosaccharide?
Triose
The name of 5 carbon atoms in a monosaccharide?
Pentose
The name of 6 carbon atoms in a monosaccharide?
Hexose (aka glucose)
What is the hexose (aka glucose) formula?
C6H1206
What are the 2 isomers of glucose?
Alpha and beta
Whats the difference between alpha and beta glucose?
Alpha is a hoh
Name 4 functions of monosaccharides?
- a source of energy in respiration
- building blocks for larger molecules
- intermediates in reactions
- consituents of nucleotides
How are disaccharides formed?
2 monosaccharides bonded together from a glycosidic bond and the elimination of water, from a condensation reaction.
What forms the disaccharide maltose?
Glucose + glucose (found in germinating seeds)
How is the disaccharide sucrose formed?
Glucose + fructose (transport of phloem)
How is the disaccharide lactose formed?
Galactose + Glucose (double G)(mammalian milk)
How do you test for the presence of sugars?
- Benedicts reagent detects reducing sugars in a solution
- equal volumes of solution and reagent are heated to 70*
- If sugar is present =
blue - green - yellow - orange - red
How are polysaccharides linked?
Large, complec polymers linked by glycosidic bonds
Features of the polysaccharide starch?
- insoluable
- cannot diffuse out of the cell
- compact molecule
- carries alot of energy in its CH and CC bonds
What is the function of starch?
Main store of glucose in plants, made out of alpha glucose.
What are the 2 types of starch?
Amylopectin and amylase
What is amylopectin?
Chains of glucose monomers joined with alpha 1-4 glycosidic bonds (chickens feet look)
What is amylase?
Linear, unbranched molecules with alpha 1-4 glycosidic bonds coiling into a helix.
How do you test for the presence of starch?
The iodine potassium iodide test, iodine reacts with starch, resulting in colour change orange/brown - blue/black.
What is glycogen
Main storage product in animals
- a1-4, a1-6 bonds
What is cellulose?
Polymer of beta glucose
Cell wall - cellulose microfibril - microfibril - cellulose molecule
What are the structural differences between starch and cellulose?
-Starch is alpha glucose, cellulose is beta glucose
- cellulose is organised in chains, starch is coiled and compacted into branches
What is chitin?
- N-acetylglucosamine
- resembles cellulose, long chains of beta glucose 1-4 monomers
- strong, waterproof and light weight
What are lipids? (3 features)
- they contain carbon, hydrogen but less oxygen
- non-polar compound
- insoluable in water but dissolve in organic solvents
What are triglycerides?
One glycerol + 3 fatty acids
How are triglycerides formed?
Formed by a condensation reaction and ester bond, broken by hydrolysis.
What are phospholipids?
- Found in the cell membrane
- Phosphate group is hydrophillic
- fatty acid tails are hydrophobic
Name the roles of lipids?
Phopholipids -
- biological membranes
- electrical insulation
Triglycerides -
- energy reserves in plants and animals
- thermal insulation
- protection
- metabolic water produced
Waxes -
- waterproofing
What is the test for fats and oils?
The emulsion test, sample + ethanol = dissolved lipids
SE + equal vol of water is shaken.
Dissolved lipids come out of the solution, forming emulsion (cloudy white sample)
What are the 2 main causes of heart disease?
- fatty acids and deposits in coronary arteries (atherosclerosis)
- high blood pressure (hypertension)
What happens if a diet is high in saturated fats?
- Low density Lipoprotein (LDL) builds up.
- Fatty material called atheroma is deposited in arteries, restricting blood flow and oxygen.
- Can result in angina, myocardial infarction or heart attacks.
What happens if a diet is high in unsaturated fats?
- More high density lipoproteins (HDL) is produced, which carries away harmful fats.
- The higher the ration of HDL, the lower the risk of heart disease or cardio-vascular disease.
What are proteins?
- carbon, hydrogen, oxygen and nitrogen.
- made out of monomers of amino acids
- chains of amino acids are called polypeptides
- 20 amino acids are used to make up proteins
What is the structure of an amino acid?
Attached to a central C atom are -
- amino group (NH2) at one end (Nterminal)
- carboxyl group (COOH) at the other end (Cterminal)
- a hydrogen atom
- the R group (variable in each amino acid)
What is a peptide bond?
The chemical bond formed between the condensation reaction of an amino group of one amino acid and the carboxyl group of another.
What is the primary structure of a protein?
Order of amino acids in a polypeptide chain.
What is the secondary structure of a protein?
The shape the polypeptide forms due to hydrogen bonding between O and H groups,
Causes the peptide to spiral into a-helix or B-pleated (sheet)
What is the tertiary structure of a protein?
A-helix can be twisted to form a more complex structure
The shape is maintained by-
- hydrogen bonds
- ionic bonds
- disulphide bonds
- hydrophobic interactions
What is the quaternary structure of a protein?
- some polypeptide chains don’t function unless in combination
- may be associated with large, complex molecules like haemoglobin.
What are fibrous proteins?
- long thin molecules, insoluable in water
- structural function like bone
- polypeptides are in parallel chains or sheets, cross linkages causing long fibres
- strong and tough
What are globular proteins?
- compact and folded into spherical molecules
- soluable in water
- enzymes, antibodies, plasma proteins and hormones
What is the test for proteins?
The biuret test
- solution + biuret reagent (NaOH and Cu2SO4 react)
- creates blue CUOH
- interacts with peptide bonds in the protein, so turns purple
- the more concentrated the protein, the darker the purple.
