Unit 1 - Cells and Protein Flashcards
Eukaryotic cells have large/ small surface area:volume
Small due to size
What do eukaryotic cells provide to increase surface area
System of internal membranes so vital functions can take place
Full name of ER
Endoplasmic reticulum
What is the ER
Membrane network continuous of nuclear membrane
What is the cytosolic face
Side that faces cytoplasm
Difference between rough ER and smooth ER
rough ER has ribosomes on cytosolic face - smooth ER doesnt
What is the Golgi Apparatus
Series of flattened membrane discs
- connected to allow mollecules to move along GA
- adjacent ER
Define vesicle
Transport material between membrane compartments
-consist of aqueous solution enclosed by lipid bilayer
Definie secretory vesicle
Vesicle that transports hormones ect. from organelles to specific sites at cell membrane where it docks on and releases content
What are Lysosomes
Membrane bound organelles containing variety of hydrolases
What do hydrolases do
Digest protein, lipids, nucleic acid and carbohydrates
What is the interior of a Lysosome like
Acidic - allows optimal enzyme function
What is a signal sequence
Short strech of amino acids at one end of the polypeptide chain that determines location of protein in cell
What are covalent modifications
Enzyme calatlysed alterations of synthesised proteins
What do covalent modifications include
Addition or removal of chemical groups - can target single thpe of amino acid or myltiple amino acids and will change the chemical properties of the site
When does post translational modification take place
As molecules move through Golgi Disks in vesicle thay bud off from one disc and fuse to next
Post translational modifications (8)
Phosphorylation, Methylation, Lipidation, Acetylation, SuMoylation, Ubiquitination, Glycosylation, Hydroxylation
What is Phosphorylation
Addition of Phosphate to serine/threonine/thyrosin
What is Methylation
Addition of CH4 group usually to Lysine/ arginine Vesicle
What is Lipidation
Attachment of lipid/ fatty acid to protein chain
What is Acetylation
Addition of Acetyl group to N-terminus of protein/ Lysine residue
What is SuMo
Small ubiquitin like modifier
What is SuMoylation
Addition of SuMo to target protein
What is ubiquitination
Addition of ubiquitin to Lysine residue of target protein of degredation
What is libiquitin
Small protein
What is glycolysation
Attachment of sugar usually to N or O in amino acid side chain
What is hydroxylation
Attachment of -OH group to side chain of protein
What are microtubules
Hollow, fibrous shafts that support give cell shape
What is a secretory protein
Any protein secreted by a cell
What are 2 examples of secretory proteins
Hormones (eg insulin), emzymes (eg trypsin)
Where are secretory proteins translated
In ribosome on RER
Difference in secretory vesicles and vesicles (mobility)
Secretory vesicles- transport cell secretion = can move
Vesicles- membrane bound = cant move
What does precursor stand for
Parent
Many secretory vesicles are synthesised and (1) and require (2) to produce (3)
1 inactive precursors
2 proteolytic cleavage
3 active protein
What is proteolytic cleave
A type of posttranslational modification eg digestive proteins
What are amino acids and what do they do
Building blocks of protein
- determine structure
Whats a monomer
Molecule that may bind to other molecules to form polymer
What is a polymer
Large molecule made of subunits (monomers)
Proteins are monomers/polymers
Polymers
What type of bonds links amino acids
Peptide bonds
What type of binds are peptide bonds
Covalent bonds
Amino group
H3N
Amino acids have same (1) but (2) may differ
1 basic structure
2 R- Groups
Types of amino acids
Acidic/ basic/ polar/ non polar
Properties of acidic amino acids
Negatively charged
- hydrophilic
- COO-
- pH 7
Properties of basic amino acids
Positively charged
- hydrophilic
- NH3
- pH7
Properties of polar amino acids
- hydrophilic
- C=H/ CH/ NH
Properties of non polar amino acids
- hydrophobic
- hydrocarbon group
Low pH = (1)
High pH = (2)
1 pos charge
2 neg charge
Define Isoelectric point
pH at which net charge is 0
How does isoelectric point affect amino acids
They are least soluble at isoelectric point
