Understanding:
• Living organisms synthesise many different proteins with a wide range of functions
Proteins are a very diverse class of compounds and may serve a number of different roles within a cell, including:
- Structure – e.g. collagen, spider silk
- Hormones – e.g. insulin, glucagon
- Immunity – e.g. immunoglobulins
- Transport – e.g. haemoglobin
- Sensation – e.g. rhodopsin
- Movement – e.g. actin, myosin
- Enzymes – e.g. Rubisco, catalase
Mnemonic: SHITS ME
Application:
• Rubisco, insulin, immunoglobulins, rhodopsin, collagen and spider silk as examples of the range of
protein functions
The following are specific examples of the different functions of proteins:
Structure
- Collagen: A component of the connective tissue of animals (most abundant protein in mammals)
- Spider silk: A fiber spun by spiders and used to make webs (by weight, is stronger than kevlar and steel)
Hormones
- Insulin: Protein produced by the pancreas and triggers a reduction in blood glucose levels
- Glucagon: Protein produced by the pancreas that triggers an increase in blood glucose levels
Immunity
- Immunoglobulins: Antibodies produced by plasma cells that are capable of targeting specific antigens
Transport
- Haemoglobin: A protein found in red blood cells that is responsible for the transport of oxygen
- Cytochrome: A group of proteins located in the mitochondria and involved in the electron transport chain
Sensation
- Rhodopsin: A pigment in the photoreceptor cells of the retina that is responsible for the detection of light
Movement
- Actin: Thin filaments involved in the contraction of muscle fibres
- Myosin: Thick filaments involved in the contraction of muscle fibres
Enzymes
- Rubisco: An enzyme involved in the light independent stage of photosynthesis