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23 Cards in this Set
- Front
- Back
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What are the 3 main lipids? |
Triglycerides, sterols and phospholipids |
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How are lipids formed and what is formed? |
A condensation reaction (esterification) creating a water molecule and an ester bond (covalent bond) forms |
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What is the structure and how does a triglyceride form? |
3 fatty acids molecules bonded to a glycerol molecule. Hydroxyl groups react and form 3 ester bond -O- |
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What's the structure of a phospholipid? |
A phosphate ion and a saturated and unsaturated fatty acid bonded to a glycerol molecule (phosphate head is polar and fatty acid tail is non-polar) |
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What is the structure of a sterol? |
It is a complex alcohol molecules with a hydroxyl group and is based on a complex ring structure with a polar and non-polar end |
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Where is cholesterol produced and what is its function? |
Produced in the liver and small intestine and forms part of the bilayer in the cell membrane and regulates fluidity and strength |
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What can cholesterol form part of? |
Vitamin D and steroid hormones |
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What does polyunsaturated lipid mean? |
When a lipid contains more than one carbon double bond |
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What are the steps for the emulsion test? |
1. Sample is mixed with ethanol and water is added 2. The solution is shaken and a white emulsion suspension should form if a lipid is present |
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What is the explanation for a positive emulsion test? |
Water is more soluble than lipids in ethanol so it displaces the lipids and leaves a suspension of it |
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What are globular proteins? |
They are compact, water soluble and roughly spherically-shaped proteins |
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How do globular proteins form? |
The folding of the tertiary structure of a protein where hydrophobic r- groups are on the inside and hydrophilic r-groups are on the outside (making it soluble) |
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What is the structure and function of insulin? |
It is a globular protein that is water-soluble and is involved in the regulation of blood glucose, it needs a specific shape to bind to receptors on the cell surface membrane |
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What is a conjugated protein? |
A globular protein with a prosthetic group |
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What is the function of the haem prosthetic group? |
So that oxygen can reversibly bind to the Fe2+ ions |
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What is the structure and function of catalase? |
It has a quaternary structure with 4 haem groups, the Fe 2+ ion allows it to interact with H2O2 and speed up it's breakdown |
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What are 4 structural features of a fibrous protein? |
Formed from long polypeptide chains
It is usually in soluble due to a high proportion of hydrophobic r groups
The primary structure of the protein is usually very repetitive leading to organised structures
Cross linkages at intervals increase strength and form long fibres or sheets |
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What is the structure of keratin? |
Found in hair skin and nails and has a high proportion of sulphur-containing cysteine amino acids that can form many disulfide bridges (This makes it in flexible and insoluble if there are many of these bonds) |
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Where is elastin found? |
Found in elastic fibres in skin and walls of blood vessels
Made up of tropoelastin |
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What is the structure and function of collagen? |
It is a connective tissue found in tendons and ligaments Made up of 3 polypeptide chains wound tightly together in a triple helix |
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What are 4 functions of lipids in organisms? |
Forms cell membranes Insulation Energy store Forms part of hormones |
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What are 3 diseases linked with high cholesterol? |
Type 2 diabetes Heart diseases Strokes |
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What is the structure of haemoglobin? |
Is globular and has a prosthetic group hydrophilic r groups arranged towards the outside |
