DNA, structure, replication and organization Flashcards
The Hershey-Chase experiments
Concluded that the DNA was the genetic material in a virus
DNA structure
DNA consists of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine. Antiparallel.
Nitrogen bases in DNA
Adenine, Thymine, Guanine, Cytosine
What nitrogen bases pair together?
A-T and C-G
What is a pentose?
5 carbon sugar
Purines
Adenine and Guanine
Pyrimidines
Cytosine and Thymine
phosphodiester bond
the type of bond that links the nucleotides in DNA or RNA. joins the phosphate group of one nucleotide to the hydroxyl group on the sugar of another nucleotide
How to read DNA
5’ to 3’
RNA structure
single strand polynucleotide. Thymine is replaced by Uracil.
Three major types of RNA
mRNA, tRNA, rRNA
mRNA
messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome
tRNA
transfer RNA; type of RNA that carries amino acids to the ribosome
rRNA
ribosomal RNA; type of RNA that makes up part of the ribosome
how id the genetic information coded in the DNA molecule
must lie on the linear sequence of nitrogen bases.
DNA replication
DNA unzips into two parts and splits with the cell. In it’s new home each side of the DNA strand attack to matching nucleotides to create 2 exact copies. It is important in puberty and other times of growth as it is the reproducing of your cells.
semiconservative replication
Method of DNA replication in which parental strands separate, act as templates, and produce molecules of DNA with one parental DNA strand and one new DNA strand
conservative replication
the parental molecule serves as a template for the synthesis of an entirely new molecule
dispersive replication
a disproved model of DNA synthesis suggesting more or less random interspersion of parental and new segments in daughter DNA molecules
Meselson-Stahl Experiment
determined that DNA replication was semiconservative
replication fork
A Y-shaped region on a replicating DNA molecule where new strands are growing.
leading strand template
The DNA template strand for the leading strand. 3’.
lagging strand template
The DNA template strand for the lagging strand. 5’.
leading strand
The new continuous complementary DNA strand synthesized along the template strand in the mandatory 5’ to 3’ direction.
lagging strand
A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5’ to 3’ direction away from the replication fork.
DNA helicase
An enzyme that unwinds the DNA double helix during DNA replication
Topoisomerase
corrects “overwinding” ahead of replication forks by breaking, swiveling, and rejoining DNA strands. makes linear.
DNA primase
synthesis of RNA primer. Starts the replication.
single strand binding proteins
bind to and stabilize single-stranded DNA
DNA clamp
A protein which prevents elongating DNA polymerases from dissociating from the DNA parent strand.
DNA polymerases
a group of enzymes that bond the new nucleotides together
Okazaki fragments
Small fragments of DNA produced on the lagging strand during DNA replication, joined later by DNA ligase to form a complete strand.
DNA ligase
enzyme that chemically links DNA fragments together
replication origin
nucleotide sequence at which DNA replication is initiated
How many origins of replication do eukaryotes have?
multiple
How many origins of replication do prokaryotes have?
1
