Molecular Biology explains living processes in terms of the chemical substances involved. In this IBDP Biology blog we will learn:
- Carbon Properties and Metabolism
- Carbohydrates, proteins and nucleic acid formation
- Catabolism and Anabolism
Carbon Atoms
Metabolism: The sum of all the chemical reactions in the cells. Most occur in the cytoplasm catalysed by enzymes
We are Carbon based life forms
Carbon atoms contain four electrons in their outer shell - this allows for four covalent bonds with other types of atoms to be formed (Methane is CH4)
Covalent bonds: Strongest types of bonds between atoms therefore stable molecules can be formed
From these properties of carbon, there is an infinite number of possible molecules involving carbon
Life is based on Carbon compounds such as:
- Carbohydrates
- Lipids (Fats)
- Proteins
- Nucleic Acids (DNA)
Carbohydrates
Contain: Carbon Hydrogen and Oxygen
Carbohydrates: Organic compounds consisting of one or more simple sugars
Monomers are commonly ring shaped molecules (sugars that consist of single sub-unit)
Isomers of Glucose: Compounds with the same chemical formula but different arrangement of atoms
Polysaccharides: All composed of Glucose
The basic linkage between the glucose subunits is a glycosidic bond
- Glycosidic bonds from
Carbon 1 to Carbon 4 (linear sturcture)
- Glycosidic bonds from
Carbon 1 to Carbon 6 (branced structure)
Cellulose: Found in plant walls made up of 1,4 glycosidic links (beta glucose)
Starch: Amylopectin has some 1,6 linkages
Glycogen: Store glucose in liver and muscles more 1,6 glycosidic linkages than Amylopectin (alpha glucose)
Lipids
Contains Carbon Hydrogen Oxygen
Insoluble in Water but soluble in non polar organic solvents
Common Lipids are:
- Triglycerides (fats and oils)
- Phospholipids (plasma membrane)
- Steriods (membrane structure)
Proteins
Contains Carbon Hydrogen Oxygen and Nitrogen
Proteins: Large organic compounds made of amino acids arranged into one or more linear chains that then fold more complex 3D structures
Nucleic Acids
Contains Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus
Sub-units are called Nucleotides
Nucleotides consist of:
- Base
- Sugar
- Phosphate
All of which are covalently bonded
If the sugar is Ribose RNA is formed, If the sugar is Deoxyribose then DNA is formed
Anabolism & Catabolism
Anabolism: The synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers by condensation reactions eg. Condensation
Condensation makes bonds and releases water (reaction). Anabolism is the process.
Condensation builds molecules an example is Protein Synthesis
Catabolism: The breakdown of complex molecules into simpler molecules including the hydrolysis of maromolocules into monomers eg. Hydrolysis
Hydrolysis breaks bonds and water is used up (reaction). Catabolism is the process.
Hydrolysis breaks down molecules an example is Digestion
That's the end of this sub-topic yay!
References
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.shutterstock.com%2Fsearch%2Fcarbon%2Batom%2Bmodel&psig=AOvVaw2GeAE9AZN0q-InCJQCqT4a&ust=1625159481465000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCMCH74Htv_ECFQAAAAAdAAAAABAN
- https://www.visionlearning.com/images/figure-images/61-d-2x.jpg
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.visionlearning.com%2Fen%2Flibrary%2FBiology%2F2%2FLipids%2F207&psig=AOvVaw2tY6T0dveAFW5cPF0gpZ3y&ust=1625159666821000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCIiMtNftv_ECFQAAAAAdAAAAABAD
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.azom.com%2Farticle.aspx%3FArticleID%3D11177&psig=AOvVaw1NQXyfN2mV8a7Z-_Qm7PIM&ust=1625160302448000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCMD97ofwv_ECFQAAAAAdAAAAABAR
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.technologynetworks.com%2Fgenomics%2Flists%2Fwhat-are-the-key-differences-between-dna-and-rna-296719&psig=AOvVaw3NFaQAt2fSJ0DAOdNew3lU&ust=1625160359222000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCMCH7qLwv_ECFQAAAAAdAAAAABAD
Drafted by Venetia (Biology)