Biochemistry Flashcards
What are the first two laws of thermodynamics?
- Energy is never created or destroyed
2. Energy transfer is never 100% due to entropy which will always increase or stay the same
What is a exergonic reaction
Where the free energy of the reactants is less than the products so ^g is negative. Hence these reactions can occur spontaneously
What is a amphipathic molecule?
What is the hydrophobic effect?
One with both hydrophillic and hydrophobic parts.
The immiscbleness of hydrophillic and phobic molecules
What is the general structure of an amino acid
What are the different classes of amino acids
NH2- CHR’- COOH
- polar, unpolar, hydrophobic, basic and acidic
What are the two types of proteins that are formed at the tertiary stage?
Fibrous- chains are parallel
Globular- formed from hydrogen bonds and ionic dipole interactions
What is structure of DNA subunits? How do they join together
Deoxyribose contains five carbons in a pentagonal shape.
Numbered from the base group clockwise, carbon 3 contains an OH group and carbon five is bonded to the phosphate group.
Nucleotides join in a condensation reaction between another nucleotides phosphate and its own hydroxyl group to form a phosphodiester bond. The energy comes from the free nucleotide cleaving its other two phosphates.
What is a nucleoside? Hence a nucleotide
A base and a sugar e.g adenine + ribose = adenosine
Nucleotide = nucleoside + phosphate
What are the two types of nucleic acids? Which go in which category?
Purines (short name long molecule): A and G
Pyrimidines (long name short molecule ): U, T, C
What are the different types of RNA molecules? What are their functions?
TRNA- carries amino acids to the ribose during protein synthesis
MRNA- carries genetic info from the nucleus to the ribosome
RRNA- makes the ribosome
What is the structure of the tRNA molecule?
It is a three stem loop molecule (three leafed clover) where there is an anticodon (complementary to the mrna molecule) and a 3’ end where amino acids are bound.
How is transcription initiated?
By TBP (tata box binding protein) binding to the TATAT box, which causes kinking of the DNA, hence allowing RNA polymerase and transcription factors to bind as they now know the start and direction of replication
What are the three stages in transcription
Initiation
Elongation., moving in the 5’ to 3’ direction
Termination- stem loops form, where they form the protein will be cleaved.
