DNA genes and chromosomes Flashcards
(25 cards)
state what each nucleotide is made up of
pentose sugar
phosphate group
nitrogenous base
joining of mononucleotide
2 mononucleotides joined tgt by condensation reaction
between deoxyribose on one and phosphate group
bond formed is called phosphodiester
new structure called dinucleotide
difference between AT and GC
AT is 2 hydrogen bonds
CG is 3 hydrogen bonds
How is DNA stable
phosphodiester backbone protects more chemically reactive organic bases
adaptations and functions of DNA
very stable structure passed down without change.
2 separate strands only held by H bonds allows for easy separation and rejoining for DNA replication and protein synthesis.
extremely large molecule so can carry lots of information.
helical cylinder of deoxyribose-phosphate backbone that protects genetic information from physical and chemical forces.
complimentary base pairing allows DNA to replicate and transfer into MRNA
What’s a dinucleotide
Condensation reaction between Penrose sugar on one mononucleotide and phosphate group of another
Phosphodiester bonds formed
What is DNA important
Deoxyribonucleic acid
Contains genetic material that codes for proteins required for development and functioning
What is DNA backbone made of
Repeated joining of sugar and phosphate group of each nucleotide (covalent bond)
Carbon 5 prime (bears phosphate) to 3 prime (bears hydroxyl)
Carbon 3 takes part in condensation reaction
Double helix
Strong sugar phosphate backbone due to covalent bonding between p and Pentose
Two strands run in opposite sides “anti parallel”
Two strands twisted to form a helix and held together by hydrogen bonds formed between nitrogenous bases
Why is DNA stable
Phosphodiester backbone protects reactive organic bases
Hydrogen bonds link bases forming bridges
Interactive forces between base pairs hold molecule together
Difference between DNA and RNA
DNA :
Double stranded
Longer
C-G and A-T
Deoxyribose (H) carbon 2
RNA
Single stranded
Shorter
C-G A-U
Ribose sugar (OH)
Names of bases
Thymine
Adenine
Cytosine
Guanine
Difference between bacterial and eukaryotic DNA
Bacterial ; short circular and not associated with proteins
Eukaryotic ; long linear and associated with proteins to form chromosomes
How a polynucleotide is made from several mono
Ester bond firms between 3’ carbon on new nucleotide and p group on og in condensation reaction this forms phosphodiester bond and water produced.
Enzyme DNA polymerase used
Which molecules make up backbone of polynucleotide
Phosphate and pentose sugar
Function of RNA
Transfers genetic info from nucleus to ribosomes for protein synthesis
DNA codes for
Functional proteins
Gene expression
Doesn’t code for anything
Why is prokaryotes DNA shorter
Only have exons
Prokaryotes and chloroplast
Both have circular DNA
No protein association
Exons only
Few genes
DNA with pro and eu
Same nucleotide structure
Joined by phosphodiester bond
DNA in mitochondria
EU longer DNA
EU contains introns
EU linear and PRO circular
EU associated with proteins
Telomeres
Found at end of chromosomes and protective structures help seal chromosomes
Define a gene
Section of DNA that contains coded info for protein synthesis
2 way cell division occurs
Nuclear division ; meiosis or mitosis
Cytokinesis ; whole cell divides
Semi conservative replication
1.DNA helicase breaks hydrogen bonds between DNA strands therefore separating them
2.both strands act as template
3.free nucleotides attach by complimentary base pairing
4. DNA polymerase joins nucleotides to new DNA strand
5.phosphodiester bond formed by condensation reaction between phosphate and dexoyribose
