Protein (2.4) Flashcards
What is the structure of an amino acid?
A central carbon atom with an amine group (NH2), a carboxyl group (COOH), a hydrogen atom (H) and a variable side chain (R).
How many amino acids are there?
There are 20 different amino acids. Nine amino acids CANNOT be made by the body. They come from food and are called essential amino acids.
What do amino acids form?
When amino acids are joined together on the ribosome they form long chains called polypeptides, which make up proteins.
How do amino acids come together to form polypeptides?
Amino acids are joined together in a condensation reaction (the removal of a molecule of water) that produces a dipeptide and water. The covalent bond between the amino acids is called a peptide bond, thus long chains of covalently bonded amino acids are called polypeptides.
How are polypeptides broken down?
Polypeptides are broken down in a hydrolysis reaction (the addition of a water molecule).
What is a protein?
A long chain of recurring monomers called amino acids.
What determines the structure of proteins?
The amino acid sequence determines the three-dimensional conformation of a protein and thus its function.
What are the two main structural forms of proteins?
Fibrous proteins (eg. collagen, fibrin)
- Have a structural role
- Water insoluble
- Long chains of polypeptides
Globular proteins (eg. haemoglobin, insulin)
- Have a functional role
- Water soluble
- Polypeptide chains are folded into a specific shape
Define denaturation
A structural change in a protein that results in the loss (usually permanent) of its biological properties.
What are the factors that cause denaturation and how do they affect the protein?
Temperature;
High temperatures break the bonds that hold the protein together, so the protein unfolds and lose its capacity to function as intended.
pH;
Changing the pH will alter the charge of the protein, which in turn will alter its solubility and overall shape.
What is the proteome?
The totality of proteins expressed within a cell, tissue or organism at a certain time. The proteome of each individual will be unique as DNA is unique and DNA codes for proteins.
What is the role of proteins within a cell?
SHITS ME
Structure: collagen, spider silk.
Hormones: insulin, glucagon.
Immunity: immunoglobins.
Transport: haemoglobin.
Sensation: rhodopsin.
Movement: actin, myosin.
Enzymes: Rubisco, catalase.
