structure and replication of DNA Flashcards
how do you get genetic information
it is inherited
DNA is a substance that
encodes genetic information of heredity in a chemical language
DNA features
very long
double-stranded molecule
shape of double helix
Stand of DNA
is made from chemical units called nucleotides
nucletide
is made up of three parts: deoxyribose sugar, a phosphate and a base
Deoxyribose molecules
have five carbon atoms, which number 1-5
The phosphate of one nucleotide
is joined to its carbon 5’5 and linked to carbon 3’3 of the next nucleotide
3’-5’ sugar - back bone
four types of bases
Adenine
Guanine
Thymine
Cytosine
Genetic information
is encoded in the sequence of bases along the length of one strand
nucleotide
one strand of DNA are linked to the nucleotides on the second strand through their bases
base pairs are held together by
hydrogen bonds
each strand
sugar-phosphate backbone 3’ end starts with a deoxyribose molecule and a 5’ end that finishes with a phosphate
two strands of DNA run
Antiparallel
chromosomes packed?
tightly coiled DNA, which is packaged with associated proteins
DNA molecule
replicate prior to cell division
Replictaion
is the process by which DNA molecules can direct the synthesis of identical copies of themselves
Template strands
DNA unwinds and unzips to form a template strand
Replication
starts at several places along DNA molecule at the same time
DNA polymerase requires …… to start
primer
primers
are short, complementary sequences of nucleotides that allow binding of DNA polymerase
3’-5’
leading strand is replicated continuously in the direction from 3’ to end towards 5’ end
nucleotides
are added fragments on the lagging stand
the fragments lagging stand
are joined together by a ligase enzyme
