Chapter 10.1 DNA Flashcards
who investigated bacteriophages?
Hershey & Chase
bacteriophages are
viruses that infect bacteria
bacteriophages are composed of
only DNA and protein
in the experiment virus DNA were labeled with
radioactive phosphorus
in the experiment virus protein was labeled with
radioactive sulfur
viruses do not have a plasma membrane, instead a _____ is present
capsid
what was the conclusion of the experiment carried out by Hershey and Chase?
DNA is the genetic material
DNA is a
nucleic acid composed of nucleotides
what are the four characteristics of DNA structure?
- 5-carbon sugar
- phosphate group
- nitrogenous bases
- hydroxyl group
the five carbon sugar in DNA is called?
deoxyribose
in DNA where is the phosphate group located on the sugar?
at the 5’ carbon
in DNA where is the hydroxyl group located in the sugar?
at the 3’ carbon
what are the 4 nitrogenous bases of DNA
- adenine
- thymine
- cytosine
- guanine
what is a phosphodiester bond?
a bond between adjacent nucleotides
a phosphodiester bond is formed between the
phosphate group of one nucleotide and the 3’ (-OH) of the next nucleotide
the chain of nucleotides has what type of orientation
5’-3’ orientation
Erwin Chargaff determined that
there are always equal proportions of purines and pyrimidines
Rosalind Franklin is known for
studies where she identified the 3-D structure of DNA
James Watson and Francis Crick proposed
a double helix structure to DNA
the bonds holding the phosphate and sugar groups are
covalent bonds
the bonds holding the nitrogenous bases are
hydrogen bonds
what 3 things are needed for DNA replication?
- something to copy
- something to do the copying
- building blocks to make the copy
what is known as the “something to copy”?
parental DNA molecule
what is known as the “something to do the copying”?
enzymes
what is known as the “building blocks to make the copy”?
nucleotide bases
the DNA polymerase reads in what direction?
3’ -> 5’
DNA is synthesized in what direction?
5’ -> 3’
DNA replication includes what 3 things?
- initiation
- elongation
- termination
the primer required to start DNA replication is synthesized by what?
primase
what is the primer needed to start DNA replication?
a short single strand of RNA
DNA helicase…
uses energy from ATP hydrolysis to unwind the DNA
what keeps the DNA strands from coming back together after they have been unzipped?
single-stranded binding proteins
which stand is pointed in the “right” direction?
the leading strand
which strand is pointed in the “wrong” direction?
the lagging strand
what are Okazaki fragments?
discontinuous strands of replicated DNA
what replaces the primers after DNA replication?
DNA polymerase
DNA ligase forms the…
final phosphodiester linkage between fragments
DNA repair mechanisms include…
- proofreading
- mismatch repair
- excision repair
explain the proofreading mechanism of DNA repair
DNA polymerase adds a nucleotide to a growing strand
explain the mismatch repair mechanism of DNA repair
replaces a whole section of DNA even if just one base has been mismatched
explain the excision repair mechanism of DNA repair
enzymes scan for mispaired bases, chemically modifies bases, or extra bases
