Protein Flashcards
What elements do proteins contain?
Proteins contain elements C, H, O, and Nitrogen. Some also contain phosphorus (P), sulphur (S), and iron (Fe).
Are proteins soluble in water?
Proteins are not soluble in water; they form a colloidal system where particles are suspended evenly (e.g. milk).
What is the monomer of proteins?
The monomer of proteins is an amino acid.
How are amino acids joined together?
Amino acids are joined by a peptide bond.
What is a dipeptide?
A dipeptide is a polymer formed when 2 amino acids are joined.
What is a polypeptide?
A polypeptide is a polymer formed when more than 2 but less than 50 amino acids are joined.
What is a protein?
A protein is a polymer formed when more than 50 amino acids are joined.
How are peptide bonds formed?
Peptide bonds form through dehydration synthesis/dehydrolysis.
What is the structure of proteins?
Proteins are made of chains of amino acids that fold into complex 3D structures held in place by disulphide bonds and weak hydrogen bonds.
What happens to proteins when they are denatured?
Proteins are sensitive to heat and incorrect pH, which can break the bonds holding their 3D structure, causing them to unfold and change shape.
What is the consequence of denaturing a protein?
The protein will no longer be able to carry out its role, and this process is irreversible.
Example: Cooking raw egg white.
What are the functions of proteins?
Proteins are important for growth and repair in cells, form the structure of organisms, carry oxygen in red blood cells (haemoglobin), serve as enzymes, provide immunity (antibodies), and act as a source of energy.
What are enzymes?
Enzymes are large globular proteins that control metabolic reactions and act as biological catalysts.
What is a catalyst?
A catalyst speeds up the rate of a reaction without being changed.
How do enzymes affect reaction energy?
Enzymes lower the amount of energy needed for a reaction.
How quickly can enzymes work?
Enzymes can catalyse thousands of reactions per second.
What are intracellular and extracellular enzymes?
Intracellular enzymes work within cells, while extracellular enzymes are secreted and work outside of cells.
What is the lock and key model?
The lock and key model explains enzyme specificity, where the enzyme is the lock and the substrate is the key, fitting perfectly at the active site.
What happens when an enzyme and substrate bind?
When they bind, an activated enzyme-substrate complex is formed, and the chemical reaction takes place.
What happens to enzymes after a reaction?
After the reaction, the enzyme is unchanged and can catalyse another reaction.
Can enzymes be denatured?
Yes, enzymes can be denatured by high temperatures and incorrect pH, which changes their shape and active site, rendering them inactive.
What is the optimal temperature for enzymes in the human body?
The optimal temperature for enzymes in the human body is 37°C.
What happens to enzymes below their optimal temperature?
Below the optimal temperature, enzymes are inactive but not permanently affected.
What happens to enzymes above their optimal temperature?
Above the optimal temperature, enzymes will denature, decreasing their activity permanently.
