COL: Proteins Flashcards
What are proteins?
Proteins are the working molecules of life. They consist of C, H, O, and N (sometimes S, P, and Fe) atoms.
Most chemical reactions that occur in living organisms are catalysed/enabled by proteins, they’re involved in cellular reactions and have a very complex structure.
What is the structure of protein?
- polymers of amino acids
- the amino acids interact with one another, causing the protein chain to twist in a specific way.
- These shapes are very important
What are 3 functions of protein?
- Play a role in transport - haemoglobin (protein in blood), carrier molecules in the cell membrane.
- Nutrients - albumin (a protein in the blood that helps maintain fluid balance and carries important substances throughout the body) in eggs, and meat protein.
- Hormones - Proteins are involved in insulin secretion and glycemic control
More functions of protein
- Movement and actions in muscle- actin & myosin
- Protection against disease - by forming antibodies
- Reserve source of energy
- Structural role in cell membranes
More functions
- Structural components in muscle, skin, cartilage, wool, hair (keratin) and hair (keratin).
- Enzymes - control chemical reactions
- Pigments eg. eye colour
- Important in structure, growth, maintenance and repair of cells.
Protein’s shape
A protein’s shape is determined by the order that amino acids are joined.The shape of a protein determines its function, if it ends in ‘ase’ = enzyme
Where are they produced?
In the cytoplasm of the cell at ribosomes. DNA controls cellular processes by directing the synthesis of RNA molecules.
What are amino acids?
Organic molecules that combine to form proteins (monomers). There are 20 different amino acids used to make the many proteins in animals and plants. They bond together by means of peptide bonds. A chain of 50< = polypeptide
50> = protein
Which organisms produce their own amino acids?
Bacteria and plants but animal cells can produce some amino acids, those that can’t be produced are called essential amino acids (these must be ingested).
Properties of proteins
- Heat/pH can cause a protein to denature
- Low temperature makes proteins inactive.
- Polymers are formed by condensation synthesis.
- For every monomer added, water is released
- Polymers are broken up by hydrolysis
- Controlled by enzymes
What are enzymes?
Proteins that act as catalysts. (catalyst: start/accelerate reactions without taking part in the reactions.)
1. They have the same properties as proteins, pH & temp specific (optimum temp in body 37 degrees), they are sometimes inactive until needed again.
Reactions
Enzymes make chemical reactions occur at a suitable rate for an organism’s survival.
What would happen without enzymes?
The metabolic rate in cells would be too slow for an organism to survive.
Anabolism (anabolic reaction)
Synthesis of larger molecules
Catabolism (catabolic reaction)
the process of breaking down large molecules into smaller ones
What happens during the lock and key mechanism of enzymes ?
The enzyme and substrate fit together like a key fits a lock. Once joined together, chemical reactions take place . When the reaction is finished, the product is released from the enzyme and can be used again.
What are examples of enzymes in daily life ?
Digestion
Lactase - helps digest lactose
Protease - helps break down protein
Lipase - helps digest fats
What is the difference between Coezymes and Cofactors
Co-enzymes = they enhance the action of the enzyme, and some are water soluble (organic) eg. B1 & 6.
Co-factors= organic nonprotein molecules that bind with the protein
molecule to form the active enzyme.
