2.1 (Molecules to Metabolism) Flashcards
1
Q
When was DNA discovered and what is the central idea?
A
Discovered in 1953; the central idea is ‘DNA makes RNA makes protein’ and this flow cannot be reversed.
2
Q
Why is the reductionist approach of molecular biologists limited?
A
Molecules can have dual roles and may interact with each other in ways that a reductionist approach overlooks.
3
Q
Why are there an almost infinite number of different possible molecules involving carbon?
A
- Carbon atoms contain four electrons in their outer shell allowing them to form four covalent bonds with potential four other different atoms
- Covalent bonds are the strongest type of bond between atoms. Stable molecules can be formed.
- Because of the stability of covalent bonds large molecules with many bonds can be formed.
4
Q
Describe carbohydrates.
A
- Contain carbon, hydrogen and oxygen
- Organic compounds consisting of one or more simple sugars
- Monomers follow the general basic formula of (CH2O)x
- Monomers are commonly ring shaped molecules
5
Q
Describe lipids.
A
- Lipids are a group of organic molecules that are insoluble in water but soluble in non-polar organic solvents
- Common lipids include triglycerides (fats – solid at room temperature and oils – liquid at room temperature), phospholipids and steroids
6
Q
Describe proteins.
A
- Contain carbon, hydrogen, oxygen and nitrogen (additionally sulphur is common component, but it is not present in all proteins)
- Proteins are large organic compounds made of amino acids arranged into one or more linear chains
7
Q
Describe nucleic acids.
A
- Contain carbon, hydrogen, oxygen, nitrogen and phosphorus
- Chains of sub-units called nucleotides
- Nucleotides consist of base, sugar and phosphate groups covalently bonded together
- If the sugar is ribose then the nucleic acid formed is RNA if the sugar is deoxyribose then DNA is formed
8
Q
What is condensation reaction?
A
- Water releasing
- Makes bonds
- Anabolic reactions build molecules
9
Q
What is hydrolysis?
A
- Water splitting
- Breaks bonds
- Catabolic reactions break down molecules
10
Q
Give examples of anabolism by condensation.
A
- Maltose synthase condenses two molecules of glucose into maltose forming a glycosidic bond
- A ribosome condenses two amino acids into a dipeptide forming a peptide bond
11
Q
Give examples of catabolism by hydrolysis.
A
- A protease hydrolyses a dipeptide into two amino acids breaking the peptide bond
- Lactase hydrolyses Lactose into Glucose and Galactose breaking the glycosidic bond
12
Q
What is vitalism and how was this falsified?
A
- ‘Only organisms can synthesise organic compounds’.
- Wöhler accidentally synthesised urea in 1828, whilst attempting to prepare ammonium cyanate
- Vitalism proposes that an unknowable factor is essential in explaining life. Vitalism on this premise is both unscientific and and unfalsifiable.
