Unit 13
- Created by: daisy
- Created on: 19-09-18 19:31
Unit 13
DNA
A-T
C-G
It is a nucleic acid or polynucleotide that contains a deoxyribose sugar unit
Carrier of genetic information that builds organisms
It is made by two polynucleotide chains that lie along side each other
The two strands twist around each other to form a double helix
The two strands are joined together by hydrogen bonds making DNA stable
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RNA
A-U
C-G
RNA is used in translation and transcription
It is a single stranded molecule
The pentose sugar in the nucleotides is ribose
Cells access the information stored in DNA by creating RNA to direct the synthesis of proteins through the process of translation
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Nucleotides
nucleotides are monomers that bond together to form the nucliec acid polymer
They join together by a condensation reaction
This reaction takes place between the -OH functional group from the phosphate group of one nucleotide and the hydrogen from the -OH group on carbon 3 of the sugar of another nucleotide
They also have functions related to cell signalling, metabolism and enzyme reactions
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Phospholipids
Are a form of lipids found in cell membranes
They are made when one molecule of gylcerol bonds with two fatty acids and one phosphate group through a condensation reaction
Phospholipids have a negatively charged phosphate group which is soluble in water
They have an uncharged hydrocarbon chain which is soluble in water
this dual solubility allows phospholipids to form cell membranes
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Tryglyceride
This is a type of lipid used for energy storage, insulation and protection
They are found in fatty tissue under the skin and surrounding the organs
Tryglycerides are soluble in water
A tryglyceride molecule is made when one molecule of gylcerol joins together with three fatty aicd molecules. The three -OH functional groups of the gylcerol molecule form bonds with the acid functional groups of three fatty aicds.
These three new bonds are called ESTER BONDS
The reaction is a condensation reaction as water is made
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Polypeptide
A polypeptide is a string of amino acids linked together
Amino acids are the basic building blocks of protein
Due to each amino acid having a unique R group, a particular amino acid sequence creates a polypeptide whose function is dependent upto its chemcial structure
Most commonly they are used for:
- proteins
- transporters
- enymes
- hormones
- structure
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Alpha Glucose
Starch is formed from alpha glucose
Alpha-glucose is a form of glucose that is in a ring shape
The ring shaped glucose structures occur when the hydroxyl OH group on the carbon 6 atom reacts with the aldehyde group on the carbon 1 atom. A water molecule is removed meaning it is a condensation reaction
Alpha H
|
OH
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Beta glucose
Cellulose is made of beta glucose
Beta OH
|
H
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Cellulose
It is a natural polymer
Cellulose is the main substance found in place cell walls and helps the plant to remain strong
humans cant digest cellulose
The molecule consists of carbon, hydrogen and oxygen atoms
Composed of a long chain of glucose molecules
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Glycogen
This is a multibranched polysaccharide of glucose
It serves as a form of energy storage in humans, animals, fungi and bacteria
it is mainly stored in the liver and muscles to provide the body with a readily available source of energy if blood glucose levels decrease
The polysaccaride structure represents the main storage of glucose in the body
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Starch
Starch is energy store compound in plants
It is made of alpha glucose
There are two types of starch straight and branching
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Amino Acids
Amino Acids are made of the 5 elements carbon, hydrogen, oxygen, nitrogen and sulfur
There is a central carbon atom called the alpha carbon with four chemical groups attached to it
- a hydrogen atom
- an amino group
- a carboxylic group
- a variable R group
There are 20 different R groups meaning there are 20 different amino acids
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Fatty acids
Saturated fatty acids
- form straight chains meanig they can line up against each other easily forming attractions between all the molecules
- The attractions require lots of energy to overcome them, as a result of this they have a high melting point and are solids at room temp
- Saturated fatty acids have a carboxylic group at the end
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Fatty acids
Unsaturated fatty acids
- they form bent chains unlike saturated fatty acids and have a double bond
- their shape means they push away from each other so attractions are not strong
- they have low melting points and are liquids and room temp
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