2.2 Biologial Molecules Flashcards
How does the formation of a dipeptide occur?
Two amino acids joining
A condensation reaction occurs between the O-H and the H to form H2O and a bond between last carbon of one NCC amino acid and the first N from the other NCC amino acid.
Draw the formation of a dipeptide.
https://www.ecosia.org/images?q=formation+of+a+dipeptide#id=C0CE21F3D6A63B85DB9495CDCA9279B549DFC922
How are peptide bonds broken between two amino acids?
A hydrolysis reaction occurs because water is used to split them. H2O is added so that the last carbon of the NCC amino acid gains an O-H and the first N from the other NCC amino acid gains a H.
Draw the hydrolysis of a peptide bond breakage.
https://www.ecosia.org/images?q=hydrolysis+of+peptide+bond+breakage#id=9E25968166637C0FA0CE45ED232744ECB47FE088
What is the primary structure of a protein?
The sequence of amino acids found in a molecule.
-changing just one amino acids can alter the function of the protein
What is the secondary structure of a protein?
The coiling or folding of an amino acid chain, which is held into either a alpha-helix or beta-pleated sheet by bonds such as hydrogen bonds.
-Some chains do not adopt any regular structure and some chains have more than one secondary structure at different ends of the chain.
What is the tertiary structure of a protein?
The overall 3-D shape of a protein molecule. Its shape arises due to interactions including hydrogen bonding, disulphide bridges, ionic bonds and hydrophobic interactions.
What is the quaternary structure?
The protein structure that consists of more than one polypeptide chain.
What is a globular protein?
One which has spherical molecules which are soluble in water and often have metabolic roles in the organism.
What are disulfide bridges?
Bonds which form between two cysteine proteins (cysteine proteins are a type of amino acid).
What is a phosphodiester bond?
The bond between a sugar a phosphate group in a polynucleotide or dinucleotide.
How does a phosphodiester bond join together two nucleotides to create a dinucleotide?
A condensation reaction occurs between the phosphate group and the sugar.
This involves the hydrogen being removed from the hydroxyl (OH) group on the carbon 3 of the ribose sugar. And the other hydroxyl group being removed from the phosphate group.
https://goo.gl/images/yixX71
This leaves a covalent (phosphodiester) bond between carbon 3 of the ribose sugar and the oxygen of the phosphate group.
H20 is left as a waste product.
What are ionic bonds in the context of protein folding?
The electrostatic attraction of oppositely charged atoms where electrons are transferred.
Some amino acids have an extra carboxylic (-COOH) group and some have an extra amine group (NH2).
An ionic bond forms between these as the carboxylic group and the amine group are oppositely charged.
What are hydrophilic/hydrophobic interactions which assist in protein folding?
The hydrophobic molecules arrange in the centre of the helix, whereas the hydrophilic arrange on the outside.
How do hydrogen bonds join atoms in water molecules?
The oxygen is more electronegative, meaning electrons are more attracted to the oxygen.
The hydrogen atoms are more electropositive meaning electrons are less attracted to the hydrogen.
This creates forces of attraction keeping the atoms together, and creates the polarity of the molecule.
What are lipids?
A group of substances that are solubule in alcohol but not water.
They are a major component of every living cell and:
-act as a source of fuel
-are macromolecules (not polymers)
What is a macromolecule?
A very large, organic molecule
What is meant by a saturated molecule?
It has no double bonds, so cannot take on any more atoms.
What is meant by a unsaturated molecule?
It has avaible double bonds, so can bond more atoms
How does a molecules saturation affect melting points?
If a molecule is more unsaturated (more double bonds), there are more ‘kinks’ in the chain so cant pack together so closely, and are therefore more fluid with a LOWER MELTING POINT.
What is a triglyceride?
A lipid molecule which is broken down in respiration to generate ATP. It consists of three fatty acid chains and a glycerol. It is the main component of fat in our bodies.
How is a triglyceride formed?
Glycerol and fatty acid chains undergo a condensation reaction to produce ester bonds between the two.
Each fatty acid chain joins to a carbon from the glycerol. The -COOH group from the fatty acid and the -OH from the glycerol react to form water, and an ester bond forms in there place, between the carbon and the oxygen.
https://www.ecosia.org/images/?q=formation%20of%20a%20triglyceride#id=7FFE6C7B7B107724ED40B1B97BB3FB21B33FF72C
What are the biological uses of triglyceride?
- store of energy
- insulation
- buoyancy
- protection
Why are triglycerides and effective store of energy?
- triglycerides are insoluble in water, so can be stored without affecting the water potential of the cell
- contains twice the energy of glucose
How are triglycerides used as insulators?
- lipids stored as adipose in mammals such as whale blubber, acting as a heat insulator
- lipids make up the myelin sheath around nerve cells, acting as electrical insulators
How are triglycerides used as protection?
- we have fat surrounding our delicate organs, acting as a shock absorber
- in bacteria, the cell wall is sometimes covered in a lipid rich outer coat.