Proteins Flashcards
(26 cards)
What are the 4 levels of a protein structure?
Primary
Secondary
Tertiary
Quaternary
What do all the 4 levels do?
Interact, as well as attract or repell
What is the primary structure of proteins?
The polypeptide.
What is the polypeptide?
Amino acid sequence. Peptide bonds
Why are there infinite possibilities of polypeptides?
20 different amino acids Could be at any length Amino acids can be in any order They all have different properties Some are polar, non polar Some are (+) or (-) charged Contain sulfur Properties of amino acids determine polypeptide folds up into a protein
What is the secondary structure of proteins?
Repeated units
What are the repeated units? What are they held together by?
Alpha helixes and beta pleated sheets. H-bonds
What is the tertiary structure of proteins?
3D folded structure
What does the 3D folded structure have and do?
A hydrophobic core and folds a single protein into a 3D structure
What does the 3D structure give proteins?
Their functional properties, such as active sites on enzymes.
What are the R-group interactions?
- Hydrophilic polar amino acids orient to the outside
- hydrophobic non polar amino acids are protected in the core
- oppositely-charged ions attract
- disulfide bridges formed between sulfur-containing amino acids
How does the 3D create its structure?
With 2 or more alpha helixes, 2 or more beta pleated sheets, or one of each
What is the quaternary structure of proteins?
Multiple subunits
Name 3 examples of quaternary structures
Haemoglobin
DNA polymerase
Ion channels in the plasma membrane
What are fibrous proteins?
Insoluble on water structure
They support and strengthen
Help support the cell
The water can’t dissolve the amino acids
It’s a long and narrow structure exposing hydrophobic and hydrophilic properties
Name 3 examples of fibrous proteins
Keratin -hair/nails Elastin -skin Collagen -tissue strengthening
What are globular proteins?
Soluble in water Functional Works as enzymes and antibodies They can float around the cell Amino acids stick together They will move around the water freely
Name 5 examples of globular proteins
Amylase -digest starch Insulin -blood sugar regulation Haemoglobin -carries oxygen and red blood cells Immunoglobulins -immune system/defense Na+ / K+ pump -membrane transport
What are some uses of proteins?
Hormones -insulin Immunoglobulin -antibodies Enzymes -catalase Gas transport -haemoglobin
What are the polar and non polar amino acids used in what kinds of channels?
Membrane channels
What die the polar sections allow?
It allows ions to pass through. Charged or polar molecules cannot normally pass through the hydrophobic
Where does the polar amino acids position themselves?
On the outside and line the protein channels for facilitate diffusion
Where do the non polar amino acids position themselves?
The position themselves with the hydrophobic tails
What does non gated mean? What does gated mean?
Non gated- tunnel
Gated- will cause a shape change to let things through
