University:
University of Wolverhampton
Course:
4PY019 | Pharmacy
Academic year:

2024
Views:

168

Pages:

3
Author:

Sara

1. Centromere: - regions of repetitive DNA = give chromosomes their constricted appearance - holds sister chromatids together in mitosis + meiosis 2. Steps of DNA replication: 1) initiation 2) elongation 3) termination 3. Replication fork 1) DNA replication starts with single molecule of DNA formation: made of 2 complementary strands 2) before start, ds DNA unzips into 2 single strands 3) helix structure undone by breakage of weak hydrogen bonds 4. Leading strand: 5' to 3' continuous 5. Lagging strand: 3' to 5' discontinuous 6. DNA primase: synthesis of RNA primers that act as templates for starting point of DNA replication 7. DNA polymerase: synthesis of new DNA molecules by adding nucleotides to leading + lagging strands 8. Topoisomerase: unwinds + rewinds DNA strands to prevent DNA from becoming supercoiled 9. Exonuclease: removes nucleotides bases from end of DNA chain 10. DNA ligase: joins DNA strands by the formation of phosphodiester bonds 11. Error correction: DNA polymerase proofreads new strand 1) excise bases that are mismatched 2) replace with the correct base 3) move forward to new base 12. Central dogma: 1/3 the concept that genetic info flows from DNA to mRNA + then to protein 13. Transcription: in the nucleus - DNA sequence rewritten using RNA nucleotides - in eukaryotes, RNA goes through additional step to become mRNA 14. Translation: - sequence of nucleotides in mRNA is translated into A.A in a polypeptide - ribosome links proteinogenic A.A to be specified by mRNA using tRNA 15. Triplets: groups of 3 successive nucleotide bases in DNA 16. Codons: - specify A.As - 3 stop codons at the end of a protein (UAA, UAG, UGA) - start codon AUG marks beginning of protein + encodes for methionine - used during translation - A.A in a specific order from N-terminus to C-terminus 17. 1) Initiation (TRANSCRIPTION): 1) TFIID binds to TATA box via TBP 2) 5 more transcription factors + RNA polymerase combine TATA box to form transcription-initiation complex 18. 2) Elongation - (TRANSCRIPTION): addition of nucleotides to MRNA 1) RNA polymerase moves along DNA template 3' to 5' 2) this builds mRNA molecule using complementary base pairing with nucleotides being added to 3' end of RNA molecule 19. 1) Initiation TRANSLATION: - 2 ribosomal subunits 40S and 60S 1. aminoacyl tRNA synthetase catalyses bonding between specific tRNAs + A.A 2. peptidyl transferase connects A and P site by peptide bonds during elongation - initiation factors eIFs - GTP = energy source 2/3 20. Stop codon: - UAA, UAG + UGA - stop signals = terminates translation - releases polypeptide from ribosome 21. Prokaryotic mRNA translation: - has a Shine-Dalgarno sequence = helps recruit mRNA to initiate protein synthesis by aligning ribosome with start codon sequence - 1st A.A = formylmethionine 22. Somatic mutations: occur in somatic cells + only affect individual in which mutation arises 23. Germ-line muta- alters gametes + passed to offspring tions: 24. Missense mutations: - changes in 1 DNA base pair that result in the substitution of 1 A.A for another in the protein - NO EFFECT 25. Duplication mu- DNA abnormally copies 1 or + times tation: - alters function of protein 3/3