Introduction Flashcards
What are the 4 biomacromolecules?
Carbohydrates, Lipids, nucleic acids and proteins
What is a bacteriophage?
A virus infected bacteria
What are retroviruses?
Viruses that insert themselves into the host genome
What is a provirus?
One that is integrated into the host genome.
Can phage viruses infect plants?
No
What is a virulent phage?
One that produces strictly through the lytic cycle.
What is positive-sense?
When a virus gets translated without replication.
What do tropoisomerases cause?
DNA unwinding and rewinding.
What does a type 1 tropoisomerases do?
Cuts one strand of DNA.
What does a type 2 tropoisomerases do?
Cuts both strands of DNA.
What is chromatin?
DNA packaged with proteins.
What are amino-terminal tails of histones sites for?
Covalent modification between nucleosomes.
What does DNA supercoiling do? (2)
Save space and controls gene expression
What is the difference between heterochromatin and euchromatin?
Heterochromatin is condensed and cannot be transcribed whereas euchromatin is less condensed and can be transcribed.
What are nucleosomes?
Histones combined with protein.
What are histones?
Proteins used to compact DNA.
What are nucleic acids made from? (3)
Sugar, base and phosphate.
How many rings do purines and pyrimidines have?
Purines have 2 rings (A, G), pyrimidines have 1 ring (C, T, U)
What is the difference between ‘deoxy’ ribose and ribose sugars?
Deoxyribose sugars are missing one OH group.
When does a hairpin occur?
When nucleotides of the same strand are inverted compliments.
What is a temperate phage?
A phage that undergoes the lysogenic cycle.
What is a prophage?
A phage that is integrated.
What to virulent phages cause?
Plarques that are clear patches of lysed cells on a lawn of bacteria.
What is the lysogenic cycle?
DNA enters the cell and then gets inserted into bacterial chromosome.
What is a temperate phage?
A phage that reproduces via the lysogenic cycle.
What is the lytic cycle?
DNA enters the cell, replicates and produces more phage particles that are released by cell lysis.
