DNA Flashcards
Purines
2 ringed nitrogenous bases: Adenine and Guanine
Pyrimidines
1 ringed nitrogenous bases: Cytosine, Thymine
Adenine and Thymine form how many bonds?
2 hydrogen bonds
Guanine and Cytosine form how many bonds?
3 hydrogen bonds
What is the base-pairing rule?
number of A = T
number of C = G
What is the structure of DNA?
Double-helix structure; nitrogenous bases in the middle; sugar and phosphates group in the ladder part
What sugar does DNA have?
deoxyribose
What sugar does RNA have?
ribose
Nitrogenous bases form…
hydrogen bonds
A sugar from one nucleotide and a phosphate group from another nucleotide form…
covalent bonds
Why is DNA replication a semi-conservative model.
Because one half of the old strand is kept to use as a template. The end result is one half of the old strand and one half of the newly made one.
DNA helicase
Breaks the hydrogen bonds between nitrogenous bases to split the DNA molecule into two separate strands
DNA polymerase
catalyzes the making of covalent bonds between sugars and phosphate groups when making a new polynucleotide chain.
What is the end result of DNA replication?
One half old strand, one half new strand.
When does DNA replication occur?
Before the cell divides
Why does DNA replication occur?
In preparation for cell division; each new cell gets the same genetic info as the OG cell
Chromatin
The form that DNA is in during normal cell activity
Chromosome
The form that DNA is in when the cell divides
Histones
Proteins that the DNA molecule is wrapped around to condense
Where is DNA?
in the nucleus
When a DNA molecule unzips at a certain region, what is this are called?
replication bubble
What did Rosalind Franklin do? What did she discover?
took an x-ray of DNA and discovered the structure of DNA (sugar and phosphate on the sides and nitrogenous bases in the middle)
What did Watson and Crick do? What did they discover?
made a model of DNA; twisted double helix and base-pairs
What makes up the backbone of DNA?
phosphate and sugar
What is Chargaff’s rule?
DNA should have a 1:1 ratio (G=C, A=T)
Why is metaphase important?
DNA lines uo to ensure exact copies can be pulled to each side
The 2 strands of DNA are ____ to each other
anti-parallel
