Molecular Building Blocks 04.10.22 Flashcards
What 4 components make up living systems?
Hydrogen, Oxygen, Carbon and Nitrogen (phosphorus)
What are the key features of a living organism?
- one or more cells
- capable of reproduction
- responds to the environment
- adapting and changing (& inheritance)
- require a source of energy
- growth and development
What are some examples of single cell life?
Bacteria, simple fungi, Amoeba. Can still interact with the environment
What is simple multicellular?
Still interacts with the environment, passes on information, divides and grows. Can form a tissue that lives
What is the difference with humans being multicellular?
We are multicellular as we have tissues and different types of tissue that communicate with each other and specialise to carry out a specific function. That is controlled by DNA and gene expression and the interaction with proteins and other molecules.
What is a macromolecule?
Simple molecules built up into large, complex molecules e.g. sugars, lipids and amino acids
They can control osmotic pressure that can be used structurally for things like collagen
E.g. Haemoglobin, DNA, glycogen, Rhodopsin, Collagen
What is the structure of macromolecules?
Heterogeneous (many different types) Often specific conformations are associated to definite functions
What are some properties of water?
- Universal solvent
- Polarity
- Hydrogen bonding
- Liquid over a range from 0-100 degrees C
- Achieves maximum density at 4 degrees C
Can water dissolve ionic and polar compounds?
Yes, it is excellent because of its polarity. It will be attracted to ions with a positive or negative charge as the oxygen is electronegative itself
What is a Hydrogen bond?
Not a covalent bond, weak, but very important in protein and DNA structures and responsible for the unusual properties of H20. Lots of H-Bonds together make a structure strong.
How is a hydrogen bond formed?
Electronegative atoms such as Oxygen or Nitrogen can attract Hydrogen atoms (protons) from other molecules. They partially share this proton, leading to a mutual attraction between the two atoms.
What does water not interact with?
-Non-polar substances
-Lipids
-Aromatic groups, with a benzene ring
These are called hydrophobic compounds
When and how did life begin?
- 3.5 billion years ago
- Defined through Mrs Nerg type processes.
- One of the earliest steps of life was the segregation of life inside a lipid bilayer (hydrophobic)
- At the same time viral replication was also arising at the same time
What do many monosaccharides form?
Polysaccharide
What do nucleotides joined together form?
Nucleic acid
What do amino acids bonded with a peptide bond together form?
Protein
What are carbohydrates?
Cn(H20)n
Made of Carbon, Hydrogen and Oxygen
We can have mono, di, oligo (a few) or polysaccharides
E.g. starch and glycogen
What are monosachharides?
- Chain of carbons, hydroxyl groups, one carbonyl group
- An aldose has an aldehyde
- a ketose has a ketone
E.g. Glucose (hexose: 6 Carbon) , ribose (pentose), erythrose (tetrose)
How are the 6 C and 5 C sugars arranged?
Normally in a cyclised (ring) structure, due to the OH and H group
How can sugars be derivatives?
Derivative: sugar molecules that have been modified with substituents other than hydroxyl groups
- Amino-sugars: containing an amino group
- Alcohol-sugars e.g. sorbitol
- Phosphorylated: makes glucose polar
- Sulphated: sulphate groups
What is a glycosidic bond?
- Hydroxyl group of a monosaccharide can react with an OH or an NH group, to form glycosides
- O-glycosidic bonds (oxygen) from di and polysaccharides
- N-glycosidic bonds (nitrogen) are found in nucleotides and DNA (as bonds to an amino group)
What is an Oligosaccharides?
Contain 3 – 12 monosaccharides.
Product of digestion of polysaccharides, or part of a complex protein or lipid.
What is a Polysaccharides?
Formed by thousands of MS joined by glycosidic bond.
Glycogen – branched polysaccharide formed of glucose residues.
What are nucleotides?
Building blocks of DNA.
Made from nitrogenous base + sugar + phosphate.
What bonds do nucleotides make?
- Bonds between bases are hydrogen bonds
- Bonds between phosphate and sugar are phosphodiester
- Phosphate bonds in nucleotides are a source of energy
What is the structure of a triglyceride?
Triglyceride = 3 fatty acids bound to glycerol
- Straight carbon chains with a methyl group and a carboxyl group at ends
What are properties of lipids?
Tend to be hydrophobic and contain no oxygen in main chain
In unsaturated fatty acids - double bonds are commonly cis, spaced at 3C intervals
How many AAs are there?
20
How is charge of AA determined?
Charge is determined by all three components and on the pH of the environment
How is polarity of AA determined?
Side chain often determines polarity (and thus solubility and permeability)
Carboxyl groups = negative
Amino groups = positive
How is a peptide bond formed?
Formed by condensation
reaction (water released)
What are some properties of an amino acid?
- Very stable
- Cleaved by proteolytic enzymes – proteases or peptidases
- Can have partial double bonds
- Flexibility around C atoms not involved in bond thus allows multiple conformations
- Usually one preferred conformation, determined mainly by types of side chains and amino acid sequence
How can enzymes be useful?
Catalysts = Provide an alternative reaction pathway with a lower activation energy
Enable reactions to occur that otherwise would not be able to occur at physiological (body) temperatures and conditions.
Bind to the reactants and convert them to products – then release the products and return to their original form
Speed up reactions and provide a way to regulate the rate of reactions
How do we regulate enzyme?
Altering concentration of substrates, products, inhibitors or activators, can also be regulated by modifying the enzyme itself by phosphorylation
what is an isoenzyme?
enzymes that have a different structure and sequence but catalyze the same reaction
What is a coenzyme?
Cannot in themselves catalyze a reaction but can help enzymes to do so. Bind with the enzyme protein molecules to form active enzymes.
