DNA structure/replication Flashcards
nucleic acid
large, linear polymers that form when nucleotides bond together.
Types of nucleic acid
DNA AND RNA
differences of RNA and DNA
RNA contains one more oxygen than DNA
the 5 carbon sugar is called ribose in RNA and called deoxyribose in DNA
Bases of DNA: GACT
Bases of RNA: GACU
RNA is single stranded and short whilst DNA is double stranded and long
double helix
a DNA molecule composed of 2 polymer strands that twist to form a helix shape
What is DNA made up of
nucleotides
What 3 chemical components do nucleotides in contain
Nitrogenous base
phosphate
5 carbon pentose sugar
How does DNA have a negaitve charge
nucelotides contain phosphate groups which have a negative charge
Types of nitrogen bases in DNA
Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)
what is the first carbon of a pentose sugar attached to
nitrogen base
what is the 5th carbon of a pentose sugar attached to
phosphate group
How are the nitrogen bases -adenine, thymine, cytosine and guanine arranged
adenine and thymine-guanine and cytosine are arranged complementary and antiparallel to each other
what does DNA form into
a double helix
What does Adenine bind with
Thymine
What does guanine bind with
cytosine
nucleotide
a monomer that makes up a large molecule of DNA
monomer
a molecule that can be bonded to another molecule to form a polymer
condensation polymerisation
is the reaction that occurs when nucleotides bond together to form a phosphodiester bond
phosphodiester bond
term used to describe the bonding of multiple nucleotides
when mutiple nucleotides bind together, the bond between them is called
a phophodieste rbond
what links nucleotides
condensation polymerisation
Steps of DNA replication
1.replication fork formation
2.Primer binding
3. elongation
4. Termination
Replication fork formation
dna helicase spilts DNA into two seperate strands
What direction can DNA only replicate in
the 3 to 5 primer direction
Primer binding
when primase binds to the 3’ end of the DNA strand
what creates primers
DNA primase
difference between lagging and leading strand
the lagging strand replicates discontinuously forming short fragments, whereas the leading strand replicates continuously
primase
creates primers during celluar DNA replication
what does DNA polymerase III do in lagging strand
synthesis the leading strand and Okazaki fragments
DNA polymerase III
duplicates chromosomal DNA
Termination(in DNA replication)
enzymes remove all primers from the original strands and replaces them with nitrogenous bases
what does ligase do
joins fragments of newly synthesized proteins(but if asked abt DNA replication should say that is joins the okazki fragments)
Okazaki Fragments
discontinuous short sequences of DNA nucleotides
why do we call the lagging strand the lagging strand
the replication of the lagging strand is delayed compared to the leading strand
types of pentose sugar in nucleotides
deoxyribose(found in DNA)
ribose(found in RNA)
how does the lagging strand become a perfect DNA strand
DNA polumease 1 cuts out the primers and replicates themwith DNA nucleotides.
where does DNA replication begin
beginning of orgin of replication(oriC)
where does DNA replication proceed towards/end
the terminus
Why do cells replicate
growth and development
maintenance of cells and repair and replacmement of damaged cells
reproduction-
what does it mean when you see word condensaiton
water will be produced
what carbon is attached to the phosphate and what carbon is attached to the sugar molecule and what carbon is attached to the nitrogen base
carbon 5 is attached to the pentose sugar and phosphate group
Carbon 1 is attached to the nitrogen base
How many bonds does A and T have
How many bonds does C and G have
A and T has 2 hydrogen bonds
C and G has 3 hydrogen bonds
What does the base ‘U’ that replaces T stand for in RNA
Uracil
What happens when phosphate group at carbon 5’ of one nucleotide bonds with the with hydroxyl group at carbon 3’ of the neighbouring nucleotide in the strand
a phosphodiester bond is formed and a molecule of water is released -
types of rna
Trna-transfer rna bring amino acids to ribsomes
Rrna-ribsomal rna makes up the ribsome
Mrna-is a copy of dna
all functions of DNA
sends out insturctions to make proteins
contains the genetic material for growth and reproduction
Controlsall cells functions
DNA polymerase 1
DNA polymerase 1 cuts out the primers and replicates them with DNA nucleotides.
chromatin
dna wrapped around histones
what bonds are broken down when the DNA is unzipped into two strands
hydrogen bonds
If the cells didn’t go through the g2 phase
they may lead to genetic issues, mutations, cancer and apopsotisis
