definitions Flashcards
Organic Molecule
Contain C and H.
Proteome
Complete set of proteins expressed by the organism at a certain point in time.
Primary Structure
Linear sequence of amino acids in the polypeptide chain.
Secondary Structure
Folding/coiling of regions of the polypeptide chain.
Tertiary Structures
Folding/coiling of the entire polypeptide chain, resulting in its 3D structure.
Quaternary Structure
2 or more polypeptide chains joined together to form a single functional protein.
Chaperonins
Proteins that assist with the folding of other proteins.
Fibrous Proteins
Elongated and insoluble.
E.g. Catalase
Globular Proteins
Folded and coiled into a spherical tertiary and/or quaternary structure. Generally soluble.
E.g. Collagen
Denaturisation
Process of altering hydrogen bonds, disulphide bridges, that create the tertiary structure.
Usually loss of function.
Cofactors
Non-biological compounds that assist with protein folding and function.
Condensation Polymerisation
Reaction during which nucleotides link together.
Gene
Region of DNA that contains information to produce a protein.
Genome
Complete set of genes in an organism.
mRNA
Carries copy of DNA from nucleus to ribosomes.
rRNA
rRNA and proteins make up ribosomes.
tRNA
Transfers amino acids from cytoplasm to ribosomes.
Ribosomes
Organelles that make proteins based on mRNA instructions.
Codon
Triplet of nucleotides.
Degenerate
More than 1 codon can code for the same amino acid
RNA Polymerase
Synthesises RNA by transcription of genes.
Promoter
Binding region for RNA polymerase.
Exons
Sections of gene that codes for protein
Introns
Sections of gene that does not code for protein.
Transcription
Production of mRNA from DNA in nucleus.
Initiation:
Transcription factors join to RNA polymerase.
RNA polymerase recognises it, attaching and unzipping the DNA molecule by breaking hydrogen bonds.
Elongation:
RNA polymerase moves along, creating a transcription bubble. It moves from 3’-5’on the DNA and creates the mRNA prime from the 5’-3’ direction.
Termination:
Transcription ends when RNA polymerase reaches the termination codon and detaches.
The DNA molecule reforms.
RNA Processing
5’ cap added to 5’ end.
Poly-A tail added to 3’ end.
Splicing removes introns and joins exons together.
Alternative Splicing
mRNA can be spliced in many ways as some exons may be removed.
Translation
Codons on mRNA translated into amino acid sequence by ribosomes.
Initiation:
Ribosome attaches to 5’ end of mRNA strand, moving along until it reaches the start codon.
tRNA binds joins to start codon, attaching to complementary bases.
Elongation:
Complementary tRNA molecules adds specific amino acids to the growing polypeptide chain via condensation polymerisation.
Termination:
When stop codon reached, polypeptide chain released into the cytoplasm or rough endoplasmic reticulum.
Regulatory Genes
Code for transcription factors that control rate of expression for other genes.
Structural Genes
Code for proteins that are not involved in gene regulation.
Operon
Unit of DNA, consisting of regulated clusters of related genes.
Enzyme
Organic catalysts that increase the rate of metabolic reactions by lowering the activation energy.
Active Site
Part of enzyme formed by tertiary folding that interacts with specific substrate to catalyse a specific reaction.
Lock and Key Model
Substrate has a complementary shape to active site.
Induced Fit Model
Substrate binds to active site and creates a ‘conformational change’ of active site so they fir better.
Catabolic Reactions
Substrates broken down and energy released.
Anabolic Reactions
Require input of energy to produce larger molecules from smaller substrates.
Reversible Inhibition
Bonds between inhibitor and enzyme weak and can be easily broken.
Irreversible Inhibition
Bonds between inhibitor and enzyme are strong and can’t be broken.
Competitive Inhibition
Shape of inhibitor is complementary to shape of active site, blocking substrate from binding.
Non-competitive Inhibition
Inhibitor binds to an allosteric site, changing the shape of the enzyme’s active site.
Coenzymes
Non-protein, organic cofactors.
Cytokines
involved in communication between immune cells.
Apoptosis
Programmed cell death.
Vector
Organism that spreads disease to others but is not affected by it.
Virus
Highly infectious pathogen that infects living cells and uses the cell’s metabolic machinery to replicate.
Prion
Misfolded proteins that have pathogenic properties.
Bacteria
Unicellular prokaryotes that can have pathogenic properties.
Antigen
Specific group of molecules that can induce an immune response.
Self-Antigen
Displayed by cells of organism.
Non-self-Antigen
Not displayed by cells of organism.
Foreign material provoking an immune response.
First Line of defence
Physical, chemical microbiological barriers that provide innate resistance.
Innate Immune Response
Non-specific, fast acting response against pathogens that have entered the organism.
Leukocytes
White Blood cells
Phagocytes
Leukocytes that engulf and breakdown pathogens via phagocytosis.
Complement Proteins
Proteins that circulate in the blood and create pores in pathogen’s membrane, enhancing phagocytosis.
Opsonisation
Tagging of antigens, attracting phagocytes to pathogen.
Interferons
Cytokines that are produced by host cell infected by virus. Activates nearby cells to increase resistance and create antiviral proteins.
Inflammation
Accumulation of fluid, plasma proteins and leukocytes that occurs when tissue is damages or infected.
Fever
Increase in body temperature to create unfavourable environment for pathogen.
Adaptive Immunity
Specific, slower response against pathogens.
Results in immunological memory.
Immunological Memory
Ability to remember antigens after primary exposure to create more effective secondary response upon re infection.
Lymphocytes
White Blood Cells that are specific for adaptive immune response.