Module 1 Flashcards
Which prime do mRNA strand run?
5’ to 3’
Which way do tRNA run?
3’ to 5’
How does a protein get made?
Ribosomes attach to mRNA, tRNA attaches at the anticodon to the specific codon associated with codon. Once this occurs, the next tRNA attaches to the next codon, the codon at the other end both join starting the protein.
How does a tRNA gain its codons for protein synthesis (opposite end of anticodon)?
A protein attaches and adds it
What ways do mRNA and tRNA run when together?
mRNA 5’-3’ and tRNA 3’ to 5’
What experiment found the codon sequences and steps?
Cell-free in vitro protein synthesis.
Steps: Grind cells, centrifuge, collect cell lysate, add Dnase, add synthetic RNA.
What is the start codons?
Aug codes for MET
What is the wobble hypothesis?
That tRNA can code for more then one RNA
What is the reading frame?
No start codon
What is an open reading frame?
Starts with a start codon
What is spontaneous mutation?
Errors in proofreading
What are induced mutations?
From mutations (e.g. UV)
What are germinal mutations?
Occur in germ line cells
Does mutation occur before or after environmental change and how do we know?
Before, experimenting with bacteria colonies, breeding on plates without something moved to without (needed to grow) and colonies grow. Mutations were always present.
What are stationary phase mutations?
They occur when populations of bacteria or fungi stop growing
What are isolalles?
No effect on phentype type.
Null alleles?
No gene products
Neutral mutations?
No affect phentypes
What is recessive suppressor-sensitive mutations?
Only visible when the second genetic factor is present.
What is a natural mutation?
Amino acid substitution results in no effect
What is a Missense mutation?
Amino acid substitution results in protein being defective
What is a nonsense mutation?
Amino acid substitution results in STOP codon
What happens to future generations if a tautomeric shift occurs?
During the 3rd generation, 1/4 children have the mutation still while the other are normal.
What causes tautomeric shift?
Change in location of hydrogen base
How do suppressor mutations revert back to their original form?
Change in the codon, second change in codon that turns the amino acid back to the start
What is an intragenic mutation?
Point mutation that occurs in same gene but different codon
What test is used to determine a mutation?
Ames Test
How do we test for chemicals that cause mutations?\
Different chemicals are added along with protein to a plate lacking a certain thing.
How do thymine dimers repair DNA replication?
Thymine dimers block replication in template strand, DNA polymerase lll restarts leaving gaps, RecA fills gaps and DNA lignase seals.
How does mismatch repair in E.coli?
Muts recognises mismatch, MutH and MutL join complex, DNA ploymerase lll fills gaps and DNA ligase seals.
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