Biology F212 Biological Molecules Key Words
- Created by: Ellen
- Created on: 30-05-13 17:18
Metabolism
Sum total of all the biochemical reactions taking place in the cells of an organism
Covalent Bonds
Very strong bonds formed when electrons are shared between atoms.
Carbohydrates
Make up a group of molecules containing, hydrogen and oxygen.
Monosaccharides
The monomers of carbohydrates
Soluble in water
Sweet tasting
Form crystals
Polysaccharides
Polymers of monosaccharides
Consists of hundreds of monomers bonded together to fomr a single large molecule
Glycosidic Bond
Covalent bond formed when carbohydreate molecules join together in condensation reactions
Condensation Reaction
Type of chemical reaction where two molecules are joined together by a convalent bond.
A water molecule is released
Hydrolysis
The reaction where a molecule is broken down into two smaller molecules by the addition of a water molecule and the breaking of a covalent bond
Cellulose
A carbohydrate polymer made by bonding many beta glucose molecules
Maltose
Two alpha glucose molecules bonded together
Small, soluble, sweet and crystalline
Glucose
6 carbon monosaccharide sugar
Small, soluble, sweet and crystalline
Deoxyribose
5 carbon sugar in DNA nucleotides
Starch + Glycogen
Large molecules of alpha glucose joined by condensation reactions
Insoluble in water
Forms grains/grandules
Amino Acids
The monomers of all proteins
Structure: amino group, carbon, acid group (N-C-C)
Peptide Bond
The covalent bond formed when amino acids are joined together in condensation reactions.
Protease
The enzyme responsible for forming and breaking the peptide bonds in organisms
Deamination
Removal of the amine group of the amino acid
In the liver
Primary Structure
The sequence of amino acids found in a protein molecule
Secondary Structure
The coiling or folding parts of a protein molecule due to the formation of hydrogen bonds formed as the protein is synthesised
Alpha helix and beta pleated sheets
Tertiary Structure
The overall 3D shape of a protein molecule
the result of interactions between hydrogen bonding, formation of disulfide bridges, ionic bonds and hydrophobic interactions
Quarternary Structure
Protein structure whwere a protein consists of more than one polypeptide chain
e.g Haemoglobin and insulin
Globular Proteins
Proteins with relatively spherical molecules
Soluble in water
metabolic roles in organisms
e.g Hb + plasma proteins
Fibrous Proteins
A protein with a relatively long, thin structure
Insoluble in water
Metabolically innactive
Structural role in organisms
Haemoglobin
Globular Protein
Soluble in water
Wide range of amino acid constituants in primary structure
Contains a prosthetic group -haem
Much of the molecule is wound into Alpha helix structures
Collagen
A structural fibrous protein
Insoluble in water
Mostly left handed helix structures
Found in connective tissue, bone, skin and cartilage
Lipids
A diverse group of chemicals
Dissolve in organic solvents such as alcohol but not water
Include fatty acids, tryglycerides and cholesterol
Ester Bond
The bond formed when fatty acid molecules are joined to gylcerol molecules in condensation reactions
Glycerol
3-carbon molecule that forms the basis of lipids
Triglycerides
A molecule consisting of a glycerol molecule and three fatty acid molecules covalently bonded together
Cholesterol
A lipid molecule found in all cell membranes and involved in the synthesis of steroid hormones
Structure: 4-carbon based ring structures, small narrow and hydrophobic
Sits between the phosphlipid tails
Regulate fluidity and strength of the membrane
Phospholipid
Gylcerol molecule plus two fatty acids and a phosphate group
Part hydrophobic part hydrophillic
Forms the basis of cell membranes
Hydrogen Bond
Weak bond formed when partially positively charged groups come close to partially negatively charged groups
In water molecules and secondary and tertiary structure
Cohesion
The attraction between water molecules due to hydrogen bonding creating surface tension
Makes water columns very strong and difficult to break
Starch Test
Add iodine to the sample
Positive = brown to blue black
Reducing sugar test
Add Benadicts solution and heat to 80ºC
Positive = blue to orange-red
Non-reducing sugar
If reducing test negative
Boil with HCL
Cool and neutralise with sodium hydrogencarbonate solution or sodium carbonate
Repeat Benedicts test
Positive = blue to orange-red
Biuret test
Add biuret reagent
Positive = blue to lilac
Ethanol emulsion test
Add ethanol to extract
Dissolve lipid
Pour solution into water in another test tube
Positive = white emulsion forms near top of water
Nucleotides
The monomers of nucleic acids
Formed by honding a phosphate group, sugar molecule and a nitrogenous base
Gene
A length of DNA That codes for one or polypeptides.
Each gene occupies a specific place on a chormosome
Diff versions of the same gene are called allels
Base pairing rules
DNA = A-T C-G
RNA = A-U C-G
DNA
A stable polynucleotide molecule
Acts as an info store - bases projecting from the backbone act as a coded sequence
Pyrimidine
Thymine, cytosine and uracil
Nitrogenous bases consisting of a single ring structure
Purine
Adenine and guanine
Nitrogenous bases consisting of a double ring structure
RNA
Ribonucleic acid
Single-strand molecule that exists in three forms
tRNA
Transfer RNA
The RNA polynucleotide that is involved in protein synthesis
It transports amino acids to the ribosomes to be added to the growing polypeptide chain
rRNA
Ribsomal RNA found in the ribosomes
mRNA
Messenger RNA carries the info coding for a polypeptide from the nulceus to the ribosomes in the cytoplasm
Transcription
The assembly of an mRNA molecle that is a copy of the DNA coding strand and complementary to the template strand
Enzyme
A protien that acts as a biological catalyst
Catalyst
A molecule that lowers the activation energy needed for a chemical reaction (speeds the reaction up) but does not get used up in the reaction
Lactase
Catalyses the breakdown of milk sugar lacose into glucose and galactose monomers
Lactose intolerant people cannot produce lactase
Catalase
Catalyses the breakdown of hydrogen peroxide to water and oxygen
Produced by most organsims as hydrogen peroxide is a toxic by-product of some metabolic reactions
Rubisco
Catalyses the binding of carbon dioxide to ribulose bisphosphate for use in photosynthesis
ATP-ase
Catalyses the breakdown of ATP to produce ADP and a phosphate group
Releases energy that is used to drive processes such as active transport
Glycogen synthetase
Catalyses the joining together of glucose molecules to build up glycogen
Extracellular Enzymes
Catalyse reactions outside the cell
Intracellular Enzymes
Catalyse reactions inside the cell
Activation Energy
The amount of energy that must be applied for a reaction to proceed
Lock-and-key hypothesis
The theory of enzyme action where there enzlyme active site is complementary to the substrate molecule
Induced-fit hypothesis
The theory of enzyme action in which the enzyme molecule changes shape to fit the substrate molecule more closely as it binds to it
Inhibitor
Slows down an enzyme controlled reaction
Slows down or prevents the formation of enzyme-subsrate complexses
Competitive Inhibitor
A substance that reduces the reate of an enzyme-controlled reaction by binding to the enzymes active site
Denaturation
Changes the tertiary structure of an enzyme such that it cannot function and its function cannot be restored
Limiting Factor
In a situation where if all other conditions are kept constant, increasing the concentration of that factor will increase the rate of reaction
Cofactors
Any substance that must be present to ensure enzyme-controlled reactions take place at the appropriate rate
Coenzyme
An organic non-protein molecule that binds temporarily with the substrate to an enzyme active site
Prosthetic Groups
A coenzyme that is a permanent part of the enzyme molecule
Contribute to the final 3D shape and other properties of the molecule
Non-competitive inhibitor
Binds to the enzyme molecule in a region away from the active site to inhibit an enzyme controlled reaction
Initial rate of reaction
Rate of reaction at the beginning of the reaction
Turnover number
the number of reactions an enzyme can catalyse in one second
Related discussions on The Student Room
- I enjoy chem practicals more than bio practicals. Is a chem degree right for me? »
- Any good youtube channels for Bio + Chem a levels? »
- Biochemistry at University »
- Biochemistry vs Chemistry vs Natural Sciences »
- Grade Growth Chronicles | From C's to A's (23-24) »
- 25 mark essay question »
- Access to Science course »
- Paper 3 AQA a Level biology »
- Biochemistry Personal Statement Example »
- End of year 12 mocks diary 2023 »
Comments
No comments have yet been made