DNA Flashcards
Nucleic acids are
Large molecules contained in the nucleus that are important for transferring and storing genetic info
2 types of nucleic acids
DNA-deoxyribonucleic acid
RNA-Ribonucleic acid
Elements in nucleic acids
C H O N P
Nucleotides
Monomers
With a phosphate group,pentose backbone(deoxi or rib) and a base pair
Nucleotides bonding
Condensation reaction
Phosphodiester
Who discovered the structure of DNA
James Watson and Francis Crick
What is dna composed of
2 polynucleotide strands that are antiparallel
Adenine and thymine H bonds
2
Guanine + cytosine H bonds
3
Why does DNA with a higher GC content have a higher mp
More H bonds to break
How is DNAs structure related to its function
-Sugar phosphate backbone gives it strength
-Helical coiled shape=compact
-sequence of bases codes for amino acids
-long molecule=stores large amount of genetic info
-H bonds daily broke for replication and transcription
-Double helix protects bonds
-stable preventing code being corrupted
What is complementary to DNA polymerase 3’ or 5’
3’
Dna helicase
Breaks H bonds between base pairs
Polymerase
Adjacent nucleotides
Forms phosphodiester bonds between phosphate and deoxyribose
How is dna replicated
-helicase breaks h bonds between nucleotides
-both strands are used as templates
-free nucleotides are attracted to their complementary base
-polymerase makes phosphodiester bonds between the phosphate and deoxyribose
-2 new strands are made of half the original dna
2 models for dna replication
Conservative
Semi conservative
Conservative hypothesis
1 new DNA molecule made entirely of new material while the other was entirely old material
What is an ion
An element that has a different number of electrons than it would originally have and has a charge
Fe2+
Haemoglobin
Help bind to oxygen
Nitrate ions
Amino acids
Dna
Phosphate ions
Activate enzymes
So they can hydrolyse
Produce phospholipid
Affect osmosis
Sodium ions
Are involved in sodium potassium pump in the co transport of glucose
Aid nerve impulses
Is moved by active transport creating diffusion gradient which affects water potential
Ca2+
Nerve impulses
Muscle contracting
Synapses
H+
Générâtes ATP
• Which scientists came up with a method to test for DNA replication? Date?
Meselsohn and Stahl (1958)
• They (m+s)used an isotope of which element in their experiment? Can you name them?
14N (light nitrogen) & 15N (heavy nitrogen)
• Which organism did they(m+ s) use in their experiment?
E.Coli bacteria
• Why did they(m and s) use bacteria?
Bacteria will take in nitrogen from their surroundings into any new DNA they make!
Name the 4 bases found in RNA
Adenine, Uracil, Guanine & Cytosine
Which sugar is found in RNA?
What does RNA stand for?
ribose
Ribonucleic acid
Is RNA double or single stranded?
Name 3 different types of RNA
single
tRNA, mRNA, rRNA
tRNA location and function
cytoplasm, carries amino acids to ribosomes for protein synthesis
rRNA location and function
produced in nucleolus found in ribosomes
mRNA location and function
leaves nucleus and goes to ribosomes – protein synthesis
Eukaryotic chromosome structure
• ChromosomeslongpiecesofDNAfoundinthe nucleus.
• Chromosomesareonlyvisiblewhenthecellsare dividing (from prophase onwards).
• DNAiswrappedaroundhistoneproteinsforming nucleosomes – these coil up further to form chromatin.
• Thesenucleosomesthencoiluptightlyduringmitosis (and meiosis).
•Telomeres at the end of the chromosomes are repetitive DNA – they offer protection against degradation.
