Unit 1 Flashcards
1
Q
Affinity chromatography
A
A technique used to separate and purify proteins based on a specific binding interaction between an immobilised ligand and its binding partner.
2
Q
Bright-field microscopy
A
Technique used to observe whole organisms, parts of organisms, thin sections of dissected tissues or individual cells.
3
Q
buffer
A
a solution used to set and maintain a particular pH
4
Q
centrifugation
A
a process that uses centrifugal forces to separate components of different densities in a mixture.
5
Q
fluorescence microscopy
A
microscopy technique that uses specific fluorescent labels to bind to and visualise certain molecules or structures within cells or tissues.
6
Q
Native page
A
Molecules not denatured, separated based on shape, size and charge
7
Q
SDS page
A
Molecules denatured and given equally negative charge. Separating proteins on size alone.
8
Q
Growth factors
A
proteins that promote cell growth and proliferation
9
Q
Haemocytometer
A
Microscopic grid used to estimate the total number of cells within a sample
10
Q
Hazard
A
anything that poses a potential risk or threat to an individual or the environment.
11
Q
immunoassay
A
technique used to detect and identify specific proteins
12
Q
inoculum
A
starting material used to grow a culture from
13
Q
iso-electric point
A
the pH at which a soluble protein has no net charge and will precipitate out of a solution.
14
Q
Linear dilution series
A
A series of dilutions that differ by an equal interval
15
Q
Log dilution series
A
A series of dilutions that differ by a constant proportion
16
Q
primary cell lines
A
a culture of cells is isolated directly from animal or plant tissues; they have a finite life-span and limited expansion capacity.
17
Q
reporter enzyme
A
an enzyme linked to an antibody specific to a protein antigen; used in immunoassay techniques.
18
Q
serum
A
source of growth factors, hormones, lipids and minerals for the culture of cells.
19
Q
supernatant
A
the liquid that lies above a solid residue or pellet in centrifugation
20
Q
turbidity
A
a measure of the degree to which a fluid loses its transparency due to the presence of suspended particles or cells in suspension
21
Q
vital staining
A
a technique in which a harmless dye is sued to stain either living tissue cells or dead cells for microscopical observation to allow a viable cell count to be made.
22
Q
western blotting
A
an analytical technique used to identify and locate specific proteins in a sample of tissue homogenate or extract based on their ability to bind to specific antibodies.
23
Q
allosteric enzymes
A
enzymes that change conformation in response to a modulator.
24
Q
alpha helix
A
Polypeptide chain, coiled into a helix with hydrogen bonding occurring to maintain the arrangement
25
Alternative RNA splicing
removal of non-coding introns from a primary mRNA transcript to leave only the coding exons. several different mature Transcripts can be produced from a single primary transcript.
26
beta pleated sheets
polypeptide chain arranged in rows with the chain folding in parallèle or anti parallel arrangements
stabilised by hydrogen bonds
27
confirmation
structural arrangement of the polypeptide chains within a protein, it can be altered by factors such as pH and the bonding of ligands and modulators
28
cooperativity
changes in binding of a target molecules to one subunit chnaged the affinity of the other other subunits for the target molecule
29
disulphide bridge
a strong covalent bond that stabilises the tertiary and quaternary structures of many proteins
30
endoplasmic reticulum
a network of membrane tubules within the cytoplasm of a eukaryotic cell, continuous with the nuclear membrane
31
exon
section of RNA that is usually retain during splicing
32
glycoprotein
a protein with a carbohydrate added by post-translational modification.
33
golgi apparatus
a series of flattened membrane discs that packages proteins into membrane-bound vesicles inside the cell, before the vesicles are sent to their destination. site of post translational modifications (addition of carbohydrates)
34
hydrolyse
a class of enzymes that use water to break chemical bonds
35
ligand
a substance that can bind to a protein, it is complementary
36
lysosome
a modified golgi vesicle containing hyrolytic enzymes
37
modulators
these bond to a secondary site on an enzyme to alter its conformation: positive modulators activate enzymes and negative modulators deactivate them
38
prosthetic group
a non-protein unit tightly bound to a protein and necessary for its function
39
protein kinases
catalyse the transfer of a phosphate group from a donor (ATP) to an acceptor (Phosphorylation)
40
protein phosphatase
an enzyme that removes a phosphate group from its substrate
41
primary structure
sequence in which amino acids are found within a protein
42
secondary structure
hydrogen bonding occurring within a polypeptide forming alpha helixes or beta pleated sheets
43
tertiary structure
binding of many types occurring between the R groups of amino acids within a protein
44
quaternary structure
the arrangement of multiple folded polypeptide subunits connected together
45
protéolytique cleavage
a major form of pst-translational modification; it occurs when a protease cleaves one or more bonds in a target protein to activate, inhibit or destroy the proteins activity
46
rough endoplasmic reticulum
organelle made up of membranes with ribosomes attached,
47
signal sequence
a short stretch of amino acids at one end of the polypeptide that determines its eventual location in a cell
48
smooth endoplasmic reticulum
a membranous organelle found in most eukaryotic cells; it synthesises lipids and steroid hormones
49
electrochemical gradient
a gradient of electrochemical potential, usually for an ion that can move across a membrane, consisting of the difference in solute concentration and difference in charge across a membrane
50
facilitated diffusion
the passive transport of substances across the membrane through specific transmembrane proteins
51
fluid mosaic model
a model that describes the structure of the plasma membrane as a mosaic of components including a phospholipid bilateral, which gives the membrane a fluid character, and cholesterol, proteins and carbohydrates
52
glucose symport
an integral membrane protein involved in the transport to glucose and sodium iona across the cell membrane at the same time and in the same direction
53
integral membrane proteins
also called intrinsic proteins, they have one or more segments embedded in the phospholipid bilayer.
54
ligand gated channels
transmembrane protein channels controlled by the binding of signal molecules
55
membrane potential
an electrical gradient that forces ions to move passively in one direction; positive ions are attracted to the negative side of the membrane and vice versa.
It is the electrical potential difference and is created when there is a difference in electrical charge on the two sides of the membrane
56
peripheral membrane proteins
membrane proteins that adhere only temporarily to either side of a membrane with which they are associated
57
sodium potassium ATPase
the enzyme that acts as the sodium potassium pump - removing three sodium ionas from the cell and taking two potassium ions back into the cell during a cycle of action
58
transmembrane proteins
proteins that span a membrane and act as channels or transporters of ions
59
transporter proteins
a membrane protein involved in the movement of ions, small molecules and macromolecules across a protein.
They bind to the specific substance and unfit a conformational change to transfer the solutes across the membrane
60
voltage gated channels
a class of transmembrane proteins that form ion channels, they are activated by changes in the electrical membrane potential near the channel
61
action potential
a wave of electrical excitation along a neurons plasma membrane
62
cones
photoreceptors cells responsible for colour vision; only function in bright light
63
cyclic GMP
a second messager for visual transduction: it is present in high concentrations in receptor cells.
As part of triggering a nerve impulse: it is broken down by PDE and its reduction in concentration affects the function of ion channels in membrane of rod cells
64
depolarisation
an electrical state in an excitable cell whereby the inside of the cell is made less negative relative to the outside that it is at the resting membrane potential
65
diabetes mellitus
an inability to regulate blood glucose levels; in type 1 there is a failure to produce insulin; in type 2 there is a loss of function of insulin receptors of cell surface
66
extracellular signalling molecule
cues such as growth factors, hormones, cytokines and neurotransmitters designed to transmit specific information to target cells.
67
GLUT 4 glucose transporter proteins
the insulin-regulated glucose transporter; insulin triggers the movement of GLUT 4 transporters to the membrane surface, increasing the uptake of glucose to be converted to glycogen.
68
G proteins
also known as guanine nucleotide-binding proteins; a family of proteins that act as molecular switches inside cells, which are involved in transmitting signals from a variety of stimuli outside a cell to its interior.
In triggering of a nerve impulse: Photoexcited rhodopsin activate hundred of G proteins called transfixing, each of which activate one molecule of phosphodiesterase (PDE)
69
hormone response elements (HREs)
a short sequence of DNA within the promoter of a gene that is able to bind to a specific hormone-receptor complex and therefore regulate transcription
(They are the specific sites on DNA which cytosol complexes bind to and affect transcription)
70
hormone receptor complex
formed when steroid hormones bind to specific receptors in the cytosol or the nucleus; they bind to specific sites on DNA and affect gene expression
71
hydrophilic signalling molecule
not able to pass through membrane and so signal is transducer across by receptor molecules on the cell surface
72
hydrophobic signalling molecule
can diffuse directly through membranes ad so their receptor molecules can be within the nucleus
73
ion concentration gradient
gradients created by pump enzymes that transport ionic solutes
74
opsin
a light-sensitive protein molecule found in animals
75
phosphodiesterase (PDE)
Activated by transducins and catalysed the hyrdolysis of cyclic GMP
76
phosphorylation cascade
a series of events in which one kinase activates the next one in a sequence; phosphorylation cascades can result in the phosphorylation of many proteins as a result of the original signalling event
77
photon
basic unit of light
78
photoreceptor cells
rods and cones - found in the retina and capable of visual photo transduction
79
repolarisation
the restoration of a membrane potential following depolarisation
80
resting membrane potential
the difference in ion concentration between the inside and outside of a cell
81
retinal
a light sensitive molecule within the eye that bonds with opsin to form photoreceptors
82
rhodopsin
the retinal-opsin complex in rod cells
in triggering a nerve impulse: when retinal absorbs photon of light, rhodopsin changes conformation to photexcited rhodopsin and activated G proteins
83
rods
photreceptor cells in the retina that function in dim light and respond to low light intensities - they do not allow colour perception
84
signal transduction
conversion of extracellular signals into an intracellulaire réponse
85
threshold value
when the depolarisation reaches about -55mV, a neuron will fire an action potential.
86
transcription factor
a protein that binds to specific DNA sequences, thereby controlling the fate of transcription of genetic information from DNA to mRNA
87
transducin
a protein naturally expressed in vertebrate retina rods and cones
(maybe a G protein?)
88
anaphase
phase in which spindle micro tubules shorten by depolymerisation, sister chromatids are separated and the chromosomes are pulled to opposite poles
89
apoptosis
programmed cell death triggered by cell death signals that can be internal or external
90
caspase cascade
protease enzymes involved in a series of reactions that destroy a cell
91
cell cycle
G1 - cell growth
S - DNA replication
G2 - Prepares to Divide
M- Divides by mitosis
92
cell cycle checkpoints
checkpoints during G1, G2 and M that asses the readiness of a cell to enter the next stage of the cell cycle.
G1 - size of cell checked and damage
G2 - Success of replication and damage to DNA
M - Prgression halted until chromosomes aligned correctly and securely tied to spindles
93
centromere
the specialised DNA sequence of a chromosome that links a pair of sister chrimatids
94
cyclic proteins
proteins that control the progression of cells through the cell cycle by activating cyclin-dependent kinases.
95
Cyclic dependent kinases
When activated by cyclin, CDKs cause the phosphorylation of proteins, which stimulates the cell cycle.
96
Cytokinesis
Division of cytoplasm to form two daughter cells
97
cytoskeleton
a microscopic network of protein filaments and tubules in the cytoplasm of many living cells that supports their shape and function.
98
death signal molecules
external and internal signals that result in the activate ion of protease enzymes called caspases, which cause apoptosis.
99
G1 cyclin CDK
phosphorylation by this inhibits the retinoblastoma protein; this allows the transcription of the genes that code for proteins needed for DNA replication; allowing cells to progress from G1 to S phase.
100
growth factors
a naturally occurring substance, usually a protein or steroid hormone. capable of stimulating cellular growth, proliferation healing, and cellular differentiation.
101
interphase
phase of the cell cycle in which the cell spends majority of its time; it consists of G1, S and G2.
102
kinetochores
a complex of proteins associated with the centromere of a chromosome during cell division, to which the spindle microtubules attach.
103
metamorphosis
process that involves a significant change in an organisms physical form during development
104
metaphase
phase in which chromosomes align at the metaphase plate and attach to spindle fibres.
105
microtubule organising centre
structure found in eukaryotic cells from which microtubules are produced for the formation of spindle fibres.
106
microtubules
microscopic hollow tubes made of the proteins rub upon that are a part of the cells cytoskeleton
107
mitosis
division of the nucleus to form two new nuclei, each with a full complement of chromosomes
108
p53
a tumour suppressor protein taht can stimulate DNA repair, arrest the cell cycle or cause cell death by the activation of caspases
109
prophase
phase in which DNA condenses into chromosomes, each consisting of two sister chromatids; the nuclear membrane breaks down, the spindle forms, and chromosomes attach via their kinetochores in their centromere region
110
proto-oncogene
a normal gene, usually involved in the control of cell growth or division, which can mutate to form a tumour- promoting oncogene.
111
retinoblastoma protein (Rb)
a tumour suppressor protein that is dysfunctional is several major cancers; one function of Rb is to prevent excessive cell growth by inhibiting cell cycle prgression until a cell is ready to divide; when phosphorylated, it allows DNA replication in the S phase.
112
spindle fibres
microtubules to which chromosomes are attached by kinetochores during cell division
113
telophase
phase in which the chromosomes decondense and nuclear membranes form around them
114
tubulin
the protein that polymerises into long chains or filaments that form microtubules, which serve as a cytoskeleton for living cells.
115
tumour promoting oncogene
a mutated proto-oncogene that has the potential to cause cancer
