IMMS Flashcards
What is the function of the cytosol?
fluid matrix of the cell
Describe the structure of the nucleus.
nuclear membrane- double membrane perforated with pores
contains cellular DNA and nucleolus
What is the function of the nucleolus?
forms RNA
What are the types of nuclear DNA?
euchromatin- actively transcribing chromatin
heterochromatin- less active
What is the function of the rough endoplasmic reticulum?
protein synthesis
What is the function of the smooth endoplasmic reticulum?
lipid production
What is the general function of the Golgi?
processing and modifying proteins
What are the different parts of the Golgi and what do each do?
cis face- received vesicles from SER
medial face- forms complex oligosaccharides
transface- proteolysis
What is the function of the lysosomes?
contain hydrolytic enzymes
What are the three elements of the cytoskeleton and what size are they?
microfilaments- 5nm
intermediate- 10nm
microtubules- 25nm
What are microfilaments made of?
actin
What is the function of intermediate filaments?
anchored to transmembrane proteins and spread tensile forces
What are the types of intermediate filaments in the cytoskeleton?
cytokeratin desmin glial fibrillary acidic neurofilaments laminin vimentin
What are microtubules made of?
tubule proteins
Describe the structure of a phospholipid
hydrophilic head and hydrophobic tail
consists of a glycerol, 2 fatty acids and a phosphate head
What effect does the phospholipid bilayer have on the membrane?
gives fluidity and elasticity
What is the function of cholesterol in the cell membrane?
gives fluidity
What are glycolipids and glycoproteins function in the cell membrane?
cell signalling
What are the types of cell junctions?
tight junction adherens junction desmosomes gap junction hemidesmosomes
What is the function of tight junctions?
seals neighbouring cells together in an epithelial sheet to prevent leakage of molecules between them
What is the function of adherens junctions?
joins an actin bundle in one cell to a similar bundle in a neighbouring cell
What is the function of desmosomes?
joins intermediate filaments in one cell to those in a neighbouring cell
What is the function of gap junctions?
allows passage of small water-soluble ions and molecules
What is the function of hemidesmosomes?
anchors intermediate filaments in a cell to the basal lamina
What junctions are occluding?
tight junctions
What junctions are anchoring?
adherens
desmosomes
hemidesmosomes
What junctions are communicating?
gap junctions
What are steroid hormones derived from?
cholesterol
What is the main difference between peptide and steroid hormones?
peptide- fast response, stored in vesicles ready for release
steroid- slow response, only made and released when needed
Describe the different types of signalling
autocrine- cells release signals that act on self
paracrine- signals to nearby cells
endocrine- signalling via bloodstream via hormones (NO DUCTS)
exocrine- signalling via bloodstream via hormones (DUCTS)
Describe the distribution of water in an average person
2/3 intracellular: 28L
1/3 extracellular: 14L- 3L plasma, 1L transcellular, 10L interstitial
What is found in the ECF?
glucose, urea, Cl-, HCO3-, Na+
What is the main cation in ECF and ICF?
ECF- Na+
ICF- K+
Define osmolality
concentration of solutes in plasma per kg of solvent
Define osmolarity
concentration of solutes in plasma per litre of solution
Define osmotic pressure
how easily a solution can take in water
Define oncotic pressure
specific types of osmotic pressure concerning blood proteins (albumin)
What is oedema?
increased fluid movement from plasma to interstitial space
What are the types of oedema?
lymphatic
hypoalbumininic
venous
inflammatory
What controls serum osmolarity? How does it do so?
vasopressin (AKA ADH)
if serum osmolarity increased, ADH released and makes you thirsty
What is the smallest carbohydrate unit?
monosaccharide
What is an oligosaccharide?
3-10 monosaccharides
joined via glycosidic bonds
What is a polysaccharide?
> 10 monosaccharides
joined via glycosidic bonds
How are glycosidic bonds formed?
condensation reactions
What bonds are present in glycogen and how does this affect it’s role as an energy source?
1,6 and 1,4 glycosidic bonds
lots of terminal end points for hydrolysis
What is the difference between saturated and unsaturated fatty acids?
unsaturated: carbon carbon double bonds
saturated: NO double bonds
What are the components of a triglyceride?
3 fatty acids and 1 glycerol
What is the structure of a fatty acid?
straight chain of carbons with methyl group at one end (CH3) and carboxyl group at the other end (COOH)
What type of fatty acids are most rigid?
unsaturated
What is the structure of an amino acid?
carbon with an amino group (NH2), carboxyl group (COOH) and side chain (R)
What determines polarity of an amino acid?
the side chain (R)
Describe each protein structure
PRIMARY
sequence of linear amino acids with peptide bonds
SECONDARY
alpha helix/ beta pleated sheet
hydrogen bonds
folding due to backbone
SUPER SECONDARY
helix turn helix, beta aloha beta, zinc fingers, leucine zip
TERTIARY
folding into 3D shape
involved disulphide brides, hydrogen bonds, ionic bonds, hydrophobic bonds (folding due to R group)
QUATERNARY
multiple tertiary proteins joined together
What are the strongest and weakest bonds in protein structures?
strongest- ionic bond
weakest- van der waal forces
What are isoenzymes?
enzymes with different structures that do the same job
What is the function of coenzymes?
form covalent bonds with enzymes to maximise activity
Why is the ATP-ADP cycle energetically favourable?
ATP has 2 phosphorus