Lecture 3: PROTEINS + CELLULAR FUNCTION Flashcards
What are proteins described as?
The workhorses of the cell
What are proteins?
Giant molecules described as nanostructures or tiny molecular machines
What do proteins do?
Carry out and catalyse these processes in a cell:
- Sense and respond to their environment
- Make and break molecule
- Obtain energy it needs
- Replicate itself
Want do some proteins form?
Much of our physical makeup - muscle, ligaments, tendons, hair and nails
How are proteins structurally described?
As non-branching polymers that form macromolecules about 50-100 A in size
What is 1A?
10^-10m
What is each protein composed of?
A specific sequence of amino acids joined together by chemical bonds called peptide bonds
What is unique to each protein?
The sequence of amino acids and the length of the sequence
How many different amino acids make proteins?
20
How is protein structure determined?
By protein crystallography, electron cryo- microscopy and NMR spectroscopy
What are the ways of depicting chemical structure?
Skeletal, ball and stick and space filling
What is the skeletal model?
Each line represents a bone
What is the ball and stick model?
Each ball represents an atom and lines represent a bond
What is the space filling model?
Spheres are the size of the atoms actual radius
What are enzymes?
Proteins with the -ase suffix
What is insulin?
A cell signalling hormone
What is the function of insulin?
After a meal, insulin is generated and binds to the insulin receptor to signal cells to take up glucose
What is Trypsin involved in?
Digestion
What is the function of trypsin?
To break down proteins during digestion
What are proteases?
Enzymes which break down proteins
What do viruses and bacteria do?
Make proteins
What do viruses and bacteria use to make proteins?
The same amino acid building blocks
What does HIV do?
Makes a protease (HIV Protease) which is essential for its replication. Treatment can inhibit it
What is amylase involved in?
Digestion
What is the function of amylase?
To break down starch into sugars
Where is amylase found?
In the saliva as well as pancreatic juices
What is alcohol dehydrogenase involved in?
Metabolism
What is the function of alcohol dehydrogenase?
An enzyme that helps metabolism ethanol
What is hexokinase involved in?
Metabolism
What is the function of hexokinase?
Adding a phosphate to glucose, after glucose has been taken up by the cel
What are kinases?
Enzymes that usually add phosphates to molecules
What is haemoglobin involved in?
Oxygen transport - metabolism
What is the function of haemoglobin?
It binds to oxygen in the lungs and carries it in the blood to tissues for use in metabolism
What is ATP synthase involved in?
Metabolism and Energetics - Membrane proteins
What is the function of ATP Synthase?
It is a remarkable membrane protein that generates ATP for use in cellular functions
What are antibodies involved in?
Immune protection
What do antibodies do?
Bind to cellular invaders like bacteria and viruses to help protect the body from infection
How many SARS-CoV2 structures were solved in 2020?
More than 1000
What does SARS-CoV2 bind to?
ACE receptor
What can therapeutic antibody fragments do?
Block SARS-CoV2 from binding to the ACE receptor
What is DNA polymerase involved in?
Replication and maintenance
What is the function of DNA polymerase?
DNA polymerase binds to one strand of DNA and adds the complementary strand to it
What is RNA Polymerase involved in?
Replication and maintenance
What is the function of RNA Polymerase?
RNA Polymerase creates a single strand of RNA that is complementary to one of the strands of DNA
What are cells?
A bag of proteins, lipids and nucleic acids which are very crowded inside
