DNA unit Flashcards
purines
Adenine
Guanine
pyrimidine
Cytosine
Uracil
Thymine
What differenciates the species if the structure of DNA is the same?
Genes
Humans have ____ copies of _____ chromosomes
Humans have 2 copies of 23 chromosommes
basic structure of DNA
Double stranded,
Anti-parallel
Double helix
codons
3 lettter word (3 bases)
nucleotide
it consists of..
-one sugar
-phosphate
-a base
why do different species have different genes?
becuase they need to make different proteins
ex: humans need skin while mice need fur
when does DNA replication occur
during the s phase before cell division
Where does DNAreplication occur
In the nucleus
why does DNA replication occur
To produce idendical set of DNA
Three basic steps of DNA replication
- seperate the two sides of the DNA strand
- Allow new DNA nucleotides to join to the open original DNA strand
- proofread the base pairing and join up the new DNA molecule
Enzymes
are proteins that are specific to the one job they do
RNA nucleotides
it contains
-a sugar,
-ribose,
-a phosphate,
-a base
Where are free floating DNA and RNA nucleotides found?
in the nucleus
