Last Study Guide! Flashcards
Mutation
changes in genetic material of a cell or virus
Point Mutation
chemical changes in just one base pair of a gene, which can lead to production of an abnormal protein
What are the two types of point mutation?
base-pair substitutions, insertions, and deletions
base-pair substitutions
replaces one nucleotide and its partner with another pair of nucleotides
what are the three types of substitution mutations?
silent, missense, and nonsense
silent mutations
have no effect on the amino acid produced by a codon because of redundancy in the genetic code
missense mutations
still code for an amino acid, but not necessarily the right one
nonsense mutation
change an amino acid codon into a stop codon, nearly always leading to a nonfunctional protein
insertion and deletion mutations
additions or losses of nucleotide pairs in a gene that may alter the reading frame, producing a frameshift mutation
reading frame
the way a sequence of nucleotides in mRNA is divided into codons
mutagen
physical or chemical agents that can cause mutations
Virus
a very small infectious particle consisting of nucleic acid enclosed in a protein coat and sometimes a membraneous envelope
Bacteriophage/Phage
viruses that infect bacteria
How have bacteriophages/phages contributed to our understanding of molecular genetics?
providing a simple model system to study fundamental concepts like the nature of genetic material (DNA), gene expression regulation, and the mechanisms of DNA replication
Host Range
a limited number of host cells that a virus can infect depending on its type of nucleic acid a virus a DNA or RNA virus
DNA virus
has DNA as its genome
RNA virus
has RNA as its genome
retro virus
a specific type of RNA virus that use an enzyme called “reverse transcriptase” to convert their RNA genome into DNA once inside a host cell, allowing them to integrate into the host’s DNA
Lysogenic Cycle
The virus attaches to the host cell’s walls, and its genetic material becomes part of the host’s DNA. When the host cell replicates, the viral genetic material is replicated as well. The virus reproduces when the host cell makes proteins, and it leaves the cell through budding
Lytic Cycle
a virus’s main method of reproduction, where it invades a host cell, uses its components to create more of itself, and then destroys the cell
difference between lytic and lysogenic cycle
in lysogenic the virus is in the cell and eventually goes dormant, not harming the cell and lytic kills the cell
What type of viruses are lytic or lysogenic?
bacteriophages
restriction enzymes
bacteria defense against phages that recognize and cut up phage DNA
why are restriction enzymes important in cloning?
they allow scientists to precisely cut DNA at specific sequences, creating compatible ends on DNA fragments that can then be joined, enabling the creation of new recombinant DNA
