Biological Molecules Flashcards
What are the macromolecules for sugars, amino acids, nucleotides and lipids/fats?
Sugars = polysaccharides
Amino acids = proteins
Nucleotides = nucleic acids (DNA, RNA)
Lipids/fats = associate to form membranes
What is the composition of a cell?
70% water
1% inorganic ions
3% small organic molecules
26% macromolecules
What are the two types of monosaccharides?
Ketose - ketone based
Aldose - aldehyde based
What monosaccharides form sucrose and lactose?
Sucrose - glucose and fructose
Lactose - glucose and galactose
Explain the structure and functions of D and L isomers
Dextro isomers has the amine group on the left and carboxyl group on the right(NROC) and it’s residues are used to comprise cell walls of bacteria and is also often used in therapeutics
Levo isomers have the groups the opposite way round(CORN) and all amino acids incorporated into proteins by living organisms are in this form
Describe the structure of glucose
4 chiral centres (therefore are enantiomers)
Aldose
Dextro if the hydroxyl group on the right of the penultimate carbon away from the aldehyde or ketone
Levo if the hydroxyl group is on the left of the penultimate carbon away from the aldehyde or ketone
Long chains and ring structures
What is the difference between alpha and beta glucose?
Depends on the direction of the -OH group on carbon 1
Alpha = pointing down
Beta = pointing up
Glycosylation
In which a carbohydrate is covalently bonded to an organic molecule to form structures like glycoproteins
Glycogen
Branched Aldose 1-4 alpha bonds Unable to form tight structures Easily broken down by enzymes
Starch
Alpha 1-4 bonds
Not branched
Cellulose
Beta glucose Beta bonds Straight structure Fibril structures Very strong so can’t be digested
What is an oligosaccharide?
Carbohydrates composed of a relatively small number of monosaccharides
How are peptide bonds formed?
Condensation reaction
Between amine group of one amino acid and carboxyl group of another
What is a nucleotide made up of?
Sugar
Base
Phosphate
Describe the structure of a nucleotide
Sugar - ribose or deoxyribose
Nucleic acids are made in 5’-3’ direction
Joined through a sequence of sugar-phosphate bonds
Bases are bonded by hydrogen bonds to form double helix
Describe the structure of a triglyceride
Glycerol (Ester) head with 3 fatty acid tails
Hydrophilic head with hydrophobic tails
Explain how single molecules cause diseases such as diabetes, sickle cell disease and cystic fibrosis
Diabetes - absence of protein hormone leads to failure to regulate blood glucose
Sickle cell disease - one amino acid change in a globin chain causes haemoglobin to aggregate into a polymer
Cystic fibrosis - absence of membrane protein that transports chloride leads to altered properties of secretions
Body fats
Predominantly as food reserves
Glycerol esters of fatty acids
Unsaturated (trans) H atoms opposite
Unsaturated (cis) H atoms same side
How does cholesterol integrate into the membrane?
OH group interacting with polar head
It’s steroid scaffold interacts with the fatty acids
