Unit 1 Glossary Flashcards
Actin
Globular protein which forms microfilaments. Associated with myosin for cell movement
Affinity
The degree to which a substance tends to combine with another
Allosteric enzymes
Enzymes which change conformation in response to a modulator
Alpha helix
Polypeptide chain coiled into a helix with hydrogen bonding occurring to maintain the arrangement
Alternative RNA splicing
Removal of non-coding introns from a primary mRNA transcript to leave only the coding exons. Several mature transcripts can be produced from a single primary transcript
Antibody
Y-shaped globular protein with specificity to an antigen
Apoptosis
Programmed cell death in response to damage to DNA etc
Aquaporin
Integral channel forming proteins within the membrane which selectively allow movement of water molecules across a membrane
Aquaporin 2 (AQP2)
Channel protein found in the collecting ducts of the kidneys. They are triggered to move to the cell surface by ADH and allow increased re absorption of water into the bloodstream
Aseptic techniques
Procedures in place to prevent contamination including sterilisation of equipment and work surfaces
Bacteriorhodopdin
Light absorbing molecule found in archae. It pumps protons across the membrane creating a proton gradient which can then be used to generate ATP
Beta sheets
Polypeptide chain arranged in rows with the chain coiling in parallel or anti-parallel arrangements
Buffer
Used to set and maintain a particular pH
Caspase cascade
Caspase proteins are involved in a series of reactions (a cascade) which destroy a cell
Cell cycle checkpoints
Checkpoints which assess the readiness of a cell to enter the next stage of the cell cycle. They occur during G1, G2 and Metaphase
Centrifuge
Apparatus which spins very quickly to seperate materials due to their density - heavier componets move to the bottom (pellet). Liquid is called supernatant
Centrosome (MTOC)
Microtuble organising centre. Found near the
nucleus. Microtubules radiate from the centrosome. They form the spindle fibres so are active during cell division.
Chromatography
Has a stationary phase (e.g. paper or gel) which the mobile phase (e.g. a solvent) moves through carrying the substance being examined - different distances moved by substances of different solubility
Cooperativity
Proteins composed of several polypeptides (subunits) can show cooperativity. Changes in binding to one subunit give the other subunits a greater affinity for the molecule e.g. binding of oxygen to one haemoglobin subunit gives the other subunits a greater affinity for oxygen
Complex media
A nutrient rich growth medium providing all the basic requirements for cell growth e.g. amino acids, glucose, salts, water etc - also have specific growth factors required for animal cell lines
Cyclin
Proteins that control the progression of cells through the cell cycle by activating cyclin-dependent kinase (CDK) enzymes
Cyclin dependent kinases (CDKs)
When activated by cyclin, CDKs cause the phosphorylation of proteins which stimulate the cell cycle
Cytoskeleton
A microscopic network of protein filaments and tubules in the cytoplasm of many living cells, which supports their shape and function
Type 1 diabetes
Failure to produce insulin
Type 2 diabetes
Loss of function of insulin receptors on cell surface
G-protein
Also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior
Gated channels
Channel forming proteins controlled by signalling molecules or ion concentration
Gel electrophoresis
Used to separate samples of nucleic acid and protein by size - introduced to a gel, they move though it due to an electric current - smaller fragments move further than larger fragments
Genome
The complete set of genes or genetic material present in a cell or orgnism
GLUT4
The insulin-regulated glucose transporter. Insulin triggers the movement of GLUT4 transporters to the membrane surface, increasing uptake of glucose to be converted to glycogen
Haemocytometer
Used to estimate total number of cells withing a sample, originally used to count number of blood cells
Hazard
Anything that poses a potential risk or threat to an individual or the environment
Hydrophilic
From the Greek meaning water loving. Having a strong affinity for water
Hydrophilic signals
Signalling molecules which are not able to pass through the membrane and must have receptor molecules on the cell surface. The signal is transduced across the membrane
Hydrophobic
Literally means ‘water-fearing’. The tendency of non-polar substances to aggregate in aqueous solution and exclude water molecules i.e. seemingly repelled from an aqueous environment
Hydrophobic signals
Signalling molecules which can diffuse through membranes so their receptor molecules can be within the nucleus
Immunoassay
Uses antibodies linked with receptor enzymes to cause a colour change in the presence of a specific antigen
Induced fit
Model to describe the action of enzymes for example. When the substrate binds to the enzymes active site there is a temporary conformational change to the enzyme which increases binding and interaction with the substrate, lowering the activation energy required for the reaction
Inoculum
The staring material used to grow a culture from e.g. bacterial culture
Interphase
The phase of the cell cycle in which the cell spends the majority of its time. In preparation for cellular division, it increases in size and DNA replication occurs in preparatiion for the M phase
G1 phase
Initial growth phase of the cell including production of more cell organelles
S phase
Cell growth continues and replication of chromosomes occurs
G2 phase
Assessment of DNA replication and final preparations for mitosis
Kinase
Catalyses the transfer of a phosphate group from a donor molecule (usually ATP) to an acceptor
Ligand
A substance which can bind to a protein e.g. hormones. The protein has a shape complemntary to the ligand to allow binding to occur
M phase
Division of the nucleus and division of the cell itself
Mitosis
Division of the nucleus to form 2 new nuclei, each with a full complement of chromosomes
Cytokinesis
Division of cytoplasm to form 2 daughter cells
Microtubule
Composed of hollow straight rods made of globular proteins called tubulins govern the location and movement of membrane-bound organelles and other cell components
Modulators
These bind to a secondary site on an enzyme to alter its conformation. They can be positive modulators to activate the enzyme or negative modulators to deactivate it
Monoclonal antibodies
Antibodies produced from hybridomas which are all identical and specific to a particular antigen
Myosin
Motor protein which move along actin filaments to bring about movements in a cell
Na/KATPase
The enzyme which acts as the Sodium Potassium pump which per cycle removes 3 Sodium ions from the cell and take 2 Potassium ions into the cell
p53 protein
Protein which can activate a caspase cascade
Phosphatase
An enzyme that removes a phosphate group from its substrate
Phosphorylation
The addition of a phosphate group to a protein or other organic molecule
Post translational modification
Addition of different chemical groups to or modification of a protein to allow a particular function
Protein confromation
Structural arrangement of the polypeptide chains within a protein which can be altered due to several factors
Primary structure
The sequence in which the amino acids are found within a protein
Secondary structure
Hydrogen bonding occurring within a polypeptide forming alpha helices or beta pleated sheets
Tertiary structure
Bonding of many types occurring within a polypeptide forming alpha helices or beta pleated sheets
Quaternary structure
The arrangement of multiple folded polypeptides connected together
Proteome
The entire set of proteins expressed by a genome (larger than a genome due to PTM and Alt RNA Splicing)
R groups
Amino acids have the same basic structure with a variable R-group providing the ability of the amino acids to have different bonding occurring between them
Resting potential
The neuron maintains a difference in ion concentration between the inside and outside of the cell, high levels in the cytoplasm - this can be measured and is known as the resting potential
Retinal
Light sensitive molecule within the eye which binds to membrane proteins called opsin to from the eyes photoreceptors
Retinoblastoma
A tumour suppressor that is dysfunctional in several major cancers. One function of pRb is to prevent excessive cell growth y inhibiting cell cycle progression until a cell is ready to divide. When phosphorylated, it allows DNA replication in the S phase
Signal transduction
Conversion of extracellular signals to an intracellular response in a cell
Symport
An integral membrane protein that simultaneously transports two substances across membrane in the same direction
Synapse
Structure which allows a neurone to passa signal to another neurone or another cell
Thykaloid membrane
Membrane forming the Grana. Light energy absorbed by photosynthetic pigments causes the flow of hydrogen across the thykaloid membrane. Diffusion of the hydrogen back across the membrane drives ATP synthase and generates ATP
Transcription factor
A protein that binds to specific DNA sequences, thereby controlling the rate of transcription of genetic information from DNA to messenger RNA (mRNA)
Transmembrane
Proteins which span a membrane and ac as channels or transporters of ions
