MTM Flashcards
What is the plasma membrane?
Lipid bilayer in which proteins are embedded
What is a mitochondrion?
An organelle in which energy is extracted from food during oxidative metabolism
What makes up the cytoskeleton?
Micro tubules- tube of protein molecules
Intermediate filament- provide support and strength
Actin filament- twisted protein fibres responsible for cell movement
What does SER do?
Aids in the manufacture of carbohydrates and lipids
What is RER?
Membranes studded with ribosomes that carry out protein synthesis
What is the extracellular matrix?
Contains a network of macromolecules such as proteins and polysaccharides acts as a scaffold and stabilises the cell.
What does the centre some do?
Produces micro tubules and contains centrioles.
What is a peroxisome?
Filled with enzymes, enclosed in a single membrane and buds off the er. Breaks down lipids and destroys toxic substances via oxidation.
What are vesicles?
Transport of materials between organelles
Golgi apparatus?
Synthesises, packages and modifies molecules ready for secretion from the cell and routes new proteins to the correct compartment
Structure of mitochondria?
Double membrane and their own DNA, inner convoluted membrane forms cristae which increases the surface area for electron transport.
What are endocytosis, pinocytosis and exocytosis?
Endocytosis- the cell engulf large particles
Pinocytosis- eukaryotes ingest plasma mambrane as vesicles, type of endocytosis of soluble substances comes from ECM.
Exocytosis- vesicles fuse with the plasma membrane releasing contents into the external medium.
What are the 3 mechanisms of protein transport into organelles?
Nuclear pores- movement of RNA, proteins and ribosomes into and out of the nucleus.
Protein translocation- protein must unfold to get through the membrane, in the mitochondria, ER and peroxisomes, proteins enter the ER whilst being synthesised.
Transport vesicles- allow for the transport of substances between organelles
What is the role of endoplasmic reticulum?
Serves as an entry point for proteins destined for other organelles including, Golgi, endoscopes, lysosomes and the cell surface, enter er and are ferried in transport vesicles between organelles.
How are water soluble proteins moved?
Translocation across er membrane and released into the lumen
How do prospective cell membrane proteins move?
They partially translocate across the er membrane and become embedded
What is the cytoskeleton?
A system of crossed fine protein filaments either anchored to the plasma membrane or radiating from a central site next to the nucleus
How does the cytoskeleton move organelles?
Uses ATP to propel them along the filaments
What do the types of filaments in the cytoskeleton do?
Actin- thinnest, generate contractile forces, form a mesh beneath the plasma membrane and strengthen it.
Micro tubules- thickest, pull duplicated chromosomes and distribute them equally between daughter cells
Intermediate filaments- mechanically strengthen the cell
What is DNA?
A template, transcribed onto mRNA by RNA polymerase. 3mRNA form a codon corresponding to an amino acid.
What happens to mRNA after it has left the nucleus?
It is translated on a ribosome by tRNA onto a protein. Some of the code is redundant/ regulatory, degenerate means that the same amino acid is coded by different sets of nucleotides.
What is the primary structure of a protein?
Polypeptide chain, the sequence of amino acids. AA are lined by condensation reactions, the structure is flexible and various side chains with different properties such as polarity of hydrophilic/phobic groups determine folding.
Secondary structure
The folding of a primary structure into alpha helicopters or beta pleated sheets. Stabilised by van der waals forces, hydrogen bonds and electrostatic attraction. Alpha helices stabilised by h bonds.
Tertiary structure of a protein?
3D shape of the protein requiring the least energy to form.