Unit 1 Flashcards
What are allosteric enzymes?
Enzymes which change conformation in response to a modulator.
What is an alpha helix?
A polypeptide chain coiled into a helix with hydrogen bonding occurring to maintain the arrangement.
What is 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.
What is an antibody?
A Y-shaped globular protein with specificity to an antigen.
What are aseptic techniques?
Procedures in place to prevent contamination including sterilisation of equipment and work surfaces.
What are beta sheets?
Polypeptide chain arranged in rows with the chain coiling in parallel or anti-parallel arrangements.
What is a buffer?
Used to set and maintain a particular pH.
What is the caspase cascade?
Caspase proteins are involved in a series of reactions (a cascade) which destroy a cell.
What are 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.
What is a centrifuge?
Apparatus which spins very quickly to separate materials due to their density - heavier components move to the bottom of the tube.
What is a centrosome?
Microtubules radiate from the Centrosome and are active during cell division as microtubules form the spindle fibres.
What is 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.
What is cooperativity in proteins?
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.
For example, binding of oxygen to one haemoglobin subunit gives the other subunits a greater affinity for oxygen.
What is cyclic GMP (cGMP)?
Molecule that is broken down by phosphodiesterase in retinal cells. Reduction in the concentration of cGMP causes ion channels to close which triggers a nerve impulse in the neurons in the retina.
What are cyclins?
Proteins that control the progression of cells through the cell cycle by activating cyclin-dependent kinase (CDK) enzymes
Cyclins are essential for regulating the cell cycle and ensuring proper cell division.
What is the function of cyclin-dependent kinases (CDKs)?
Cause the phosphorylation of proteins which stimulate the cell cycle when activated by cyclin
CDKs are crucial for the progression of the cell cycle and are activated at specific points.
Define cytoskeleton.
A microscopic network of protein filaments and tubules in the cytoplasm that supports cell shape and function
The cytoskeleton is involved in various cellular processes including movement and division.
What is cytosol?
The liquid part of the cytoplasm which contains the components of the cytoskeleton and in which the cell’s organelles are suspended
Cytosol plays a key role in cellular metabolism and the transport of materials.
What is depolarization?
A reduction in the difference of electrical potential across the plasma membrane of a nerve or muscle cell
Depolarization is critical for the generation and propagation of action potentials in neurons.
What is diabetes?
Inability to regulate blood glucose levels
There are two main types: Type 1 (failure to produce insulin) and Type 2 (loss of function of insulin receptors on cell surface).
What is the endoplasmic reticulum (ER)?
Network of membrane tubules continuous with the nuclear membrane, site of protein synthesis and modification
The ER is divided into Rough ER (with ribosomes) and Smooth ER (lipid synthesis).
What distinguishes Rough ER from Smooth ER?
Rough ER has ribosomes on its surface; Smooth ER synthesizes lipids
Rough ER is involved in protein synthesis while Smooth ER is involved in lipid production and detoxification.
Define G-Protein.
Guanine nucleotide-binding proteins that act as molecular switches inside cells
G-Proteins are involved in transmitting signals from a variety of stimuli outside a cell to its interior.
What are Gated Channels?
Channel forming proteins controlled by signalling molecules or ion concentration
Gated channels play a critical role in maintaining the cell’s ion balance and in signal transduction.