Lecture 2: Biochemistry and Saccharides Flashcards
Why must all biochemical molecules be considered in aqueous solution?
Because water is hugely important factor in many molecules, being integrated into things such as proteins and allowing them to function. And frequently used during enzyme catalytic mechanisms.
What structures do each of these basic molecules make?
- Sugars
- Fatty Acids
- Amino Acids
- Nucleotides
Sugars - Polysaccharides
Fatty Acids - Fats, Lipids, Membranes
Amino Acids - Proteins
Nucleotides - Nucleic Acids
Why is carbon such an important molecule?
Because C-C covalent bonds are very stable, so compounds made up of it are harder to destroy. They can form chains so can produce large stable structures. Can form alternating double bonds which also contribute to stability. The ability to form 4 bonds for each C atom allows more variation in compounds.
What functional group will readily protonate in water?
Amines, -NH2 -> -NH3+
What group can oxidize to form cross-bridges? Known as a thiol group?
Sulfhydryl group, -SH
What is an inorganic phosphate?
Inorganic phosphates are salts of phosphate molecules. The phosphate anions and metal cations form ionic bonds.
What are organophosphates?
Organophosphates are molecules that are formed by the esterification of alcohol and phosphoric acid, (H3PO4 + -OH). They are present in many molecules such as DNA, RNA and ATP. Also used in nerve agents and pesticides. Organophosphates can have one to three R groups, non-R groups have a H attached.
How are amides formed?
Combining a carboxylic acid with a molecule containing an amine group.
What are the constituents that can form to make a phosphate ester?
An organophosphate and a free hydroxyl group
What is phosphorylation and why is it important?
Phosphorylation is a process of adding a phosphoryl group. Phosphorylation of proteins allow them to function, not all proteins require it although most use it. Phosphorylation of serine, threonine or tyrosine side chains can alter activity or function of modified protein.
Give the characteristics of carbohydrates.
Carbohydrates are carbon based organic molecules, they are made up of simple sugars, monosaccharides, meaning that they are polysaccharides. Are a source of energy for animals. Condensed and then condensed in the form glycogen. Can bind to lipids and proteins to form molecules that can perform structural or regulatory roles.
What is the difference between an aldose and ketose?
Aldoses are carbohydrates which have an aldehyde attached to them, whereas a ketose is the same but rather with a ketone group somewhere on them.
What are 3 important classes of sugars that relates to the number of carbon atoms?
Trioses, which are 3 carbon chains
Pentoses, which are 5 carbon chains
Hexoses, which are 6 carbon chains
In aqueous solution, what happens to a sugar molecules?
The majority of straight chain molecules undergoes cyclization, with the aldehyde or ketone group reacting with a hydroxyl group on the second to last carbon on the opposite end of the chain.
Describe the mechanism of cyclization in an aldohexose sugar.
The hydroxyl group on the 2’ carbon will attack the aldehyde group’s 6’ carbon, an electron pair will then be donated to the =O of the aldehyde, making it electronegative with three pairs of electrons, the oxygen from the aldehyde group has 3 spare electrons and a hydrogen, making it electropositive. The spare hydrogen is then transferred to the electronegative oxygen.
