Unit 1: Cells And Proteins 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 which binds at a secondary binding site
Alpha helix
Polypeptide chain coiled into a helix with hydrogen by ding occurring to maintain the arrangement
Alternative RNA splicing
Removal of non-coding introns from a primary mRNA transcript to leave only the coding expand. Several mature transcripts can be produced from a single primary transcript.
Antibody
Y-shapes 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 the membrane
AQP2 (aquaporin 2)
Channel protein found in the collecting duct of the kidneys. They are triggered to move to the cell surface by ADH and allow increased reabsorption of water into the bloodstream
Aseptic techniques
Procedures in place to prevent contamination including sterilisation of equipment and work surfaces
Bacteriorhodopsin
Light absorbing molecule found in Archae (one of the three domains of life, the other two being bacteria and eukaryota) 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
A solution used to set and maintain a particular pH
Caspase cascade
Caspase proteins are involved in a series of reactions (a cascade) which destroys 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 desperate materials due to their density. Heavier components move to the bottom of the tube
Centrosome (MTOC)
Microtubules radiate from the centrosome and are active during cell division as microtubules form the spindle fibres
Chromatography
A separating technique in which there is a stationary phase (paper or gel) which the mobile phase (solvent) moves through carrying the substance being examined. Different substances have different solubility in each so move different distances
Cooperativity
Proteins composed of several polypeptides (subunits) can show cooperativity. Changes in binding of 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 basic requirements for cell growth: amino acids, glucose, salts, water. They also may contain specific growth factors required for animal cell lines
Cyclin
Proteins that control the progression of cells through the cell cycle by activating cyclin- dependant kinase (Cdk) enzymes
Cyclin dependant 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 support their shape and function
Type 1 diabetes
Diabetes is the inability to regulate blood glucose levels. Type one is caused by the failure to produce insulin
Type 2 diabetes
Diabetes is the inability to regulate blood glucose levels. Type 2 is caused by loss of function is the insulin receptors on the cell surface
G-protein
Also known as a guanine nucleotide binding protein. They 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 concentrations
Gel electrophoresis
Use to separate samples of nucleic acid and protein size. The nucleic acid is introduced to angel, they move through it due to the electric current. Smaller fragments move further than larger fragments
Genome
The complete set of genes or genetic material present in a cell or organism
GLUT4
The insulin- regulates glucose transporter. Insulin triggers the movement of GLUT4 transporters to the membrane surface, increasing uptake of glucose to be converted into Glycogen
Haemocytometer
Apparatus used to estimate the total number of cells within a sample, originally used to count the number of blood cells
Hazard
Anything that poses a potential risk or threat to an individual or the environment
Hydrophilic
From the Greek word water loving. Having a strong affinity for water
Hydrophilic signalling
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 will exclude water molecules i.e seemingly repelled from an aqueous environment
Hydrophobic signalling
Signalling molecules which can diffuse through membranes so their receptor molecules can be within the nucleus
Immunoassay
The use is antibodies linked with reporter enzymes to cause a colour change in the presence of a specific antigen
Induced fit
Model to describe the action of enzymes. When the substrate binds to the enzyme 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 starting material use to grow a culture from e.g. Bacterial culture
Interphase
The phase of the cell cycle in which the cell spend the majority of its time. In preparation for cell division, it increases in size and DNA replication occurs in preparation for the M Phase
G1
Initial growth phase of the cell division including production of more cell organelles
S
Cell growth continues and replication of chromosomes occurs
G2
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 complementary to the ligand to allow binding to occur
M phase
Division is the nucleus and division of the cell itself
Mitosis
Division of the nucleus to form two new nuclei, each with a full complement of chromosomes
Cytokinesis
Division of the cytoplasm to form two daughter cells
Microtubule
Composed of hollow straight Ross made of globular proteins called tubulins and govern the location and movement of membrane bound organelles and other cell components
Modulators
These bond to a secondary site in an enzyme to alter its confirmation. They can be positive modulators to active 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 proteins which move along actin filaments to bring about movement 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 takes 2 potassium ions into the cell
p53 protein
Protein which can activate a caspase cascade
Phosphatase
An enzyme which removes a phosphate group from its substrate
Phosphorylation
The addition of a phosphate group to a protein or other organism molecule
Post translational modifications
Addition of different chemical groups to or modification of a protein to allow a particular function
Protein conformation
Structural arrangement of the polypeptide chains within a protein which can be altered due to several factors
Protein structure
The different levels of arrangement of polypeptides within a protein
Primary protein structure
The sequence in which the amino acids are found within a protein
Secondary protein structure
Hydrogen bonding occurring within a polypeptide forming alpha helices or beta pleated sheets
Tertiary protein structure
Bonding of many types occurring between the R-groups of amino acids within a protein
Quaternary protein structure
The arrangement of multiple folded polypeptides connected together
Proteome
The entire set of proteins expressed by a genome (proteome much larger than the genome)
R-groups
Amino acids have the same basic structure with a variable R-group providing the ability of the amino acids to have different binding occurring between them
Resting potential
The neurone maintains a difference in ion concentration between the inside and outside of the cell. This can be measured.
Retinal
Light sensitive molecule within the eye which bind to membrane proteins called Opsin to form the eye photoreceptors
Retinoblastoma
A tumour suppressor protein that is dysfunctional in several major cancers. One function of pRb is to prevent excessive cell growth by 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 extra cellular signals to an intracellular response in a cell
Symport
An integral membrane protein that simultaneously transports two substances across the membrane in the same direction
Synapse
The space between two neurones
Thylakoid membrane
Membrane forming the Grana. Light energy absorbed by photosynthetic pigments causes the flow of hydrogen across the thylakoid 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
Transmembrane
Proteins which span the membrane and act as channels or transporters of ions
