Biological Molecules 2.1.2 Flashcards
Describe the structure of a phospholipid and how it relates to its function.
Structure- 1 glycerol molecule & 2 fatty acids & phosphate group.
Function- the molecule is part hydrophobic and part hydrophilic. Giving it specific properties eg;
Acts as a barrier to many ions & molecules.
Basis of cell membranes when carbohydrates chains are attached
Forms glycolipids used in cell signalling.
Describe the structure and function of glycogen.
Structure- 1,4 &1,6 glycosidic bonds more 1,6 than starch = more branched = shorter = more compact.
Function- They are broken down more easily then starch into individual molecules when body needs energy. Stable insoluble storage in animals.
Describe the structure of a triglyceride and how it relates to its function.
A triglyceride’s structure is made up of 1 glycerol molecule and 3 fatty acids.
Function- an energy store and energy source.
Acts as an insulation layer eg; under skin or around nerves.
A protective layer around organs; a waxy layer on plant leaves.
Describe the structure and function of collagen
It is a fibrous protein with a quaternary structure. It’s made up of 3 polypeptide chains that are twisted around each other like rope. Strength is provided by hydrogen bonds and covalent bonds between chains. It there provides support and strength in structures such as the heart and arteries, tendons and bones and skin and cartilage. It’s insoluble.
Describe what a globular protein is.
It is one of the two main types of tertiary structures.
It is when the protein folds and coils to make a 3d shape after twisting and folding in the secondary structure.
Usually soluble in water
Used it metabolic processes as all enzymes are globular
Usually spherical in shape.
Also form protein based enzymes, plasma proteins and and antibodies.
What is a fibrous protein?
One of the two main types of the tertiary structure. It is when the protein twists into a long fibrous structure. They are important in structural roles such as that of keratin in hair and nails; and collagen in skin bone and cartilage.
Describe the protein formation within the tertiary structure.
There are two main types, globular and fibrous.
Globular- proteins with 3d shape after that forms after twisting and folding of the secondary structure.
Fibrous- Proteins with long rope like shape after folding of the secondary structure.
Bonds that hold the in place:
Weak hydrogen bond between molecules
Ionic bonds and hydrophobic interactions between different r groups if negative charge or eg ch3-
Covalent bonds between = strong
Disulphides bridges if s is in r group
Explain what the Benedicts test for reducing sugars entailed.
Tester tube= equal amounts of bright blue Benedicts solution and colourless and clear glucose.
Control tube= same as test but water used instead of glucose.
Student heated the mixture for 5 mins until colour changed. The controls fed up pale bright blue, glucose changes to orange.
Why is water a polar molecule?
Due to uneven balance of charge, the H being slightly + and the oxygen slightly - creating a dipole.
