7. Nucleic Acid And DNA Replication Flashcards
What is the name an functions of DNA and RNA?
DNA= Deoxyribonucleic acid - holds genetic info
RNA= Ribonucleic acid - transfers genetic info from DNA to ribosomes.
What does a DNA nucleotide made up of?
Pentose sugar = deoxyribose
Nitrogen containing bases = Adenine , Thymine, Cytosine, Guanine
And contains a phosphate group.
How and why does a DNA need to be kept parallel?
Kept parallel so less likely to get damaged. Parallel by pairing up Purines (Adenine and Guanine ) with pyramidines ( Thymine and Cytosine)
What bond forms on the backbone of DNA strand?
Phosphodiester bond (like a covalent bond) which is formed by condensation reaction between phosphate and deoxyribose sugar making a polynucleotide DNA molecule. Catalysed by DNA polymerase.
Phosphdiester bond is a strong bond,
What holds the polynucleotides of DNA together?
Hydrogen bonds between specific complementary base pairs (AT and CG) making a double helix with 2 polynucleotide. Many hydrogen bonds provide strength.
What are the scientists who first proposed model of DNA structure and replication?
James Watson and Francis Crick
What is the structure of a messenger RNA (mRNA)?
Linear
No hydrogen bonds
Contains codons
What is the structure of a transfer RNA (tRNA)?
Clover leaf shape
Contains some hydrogen bonds as its folded.
Contains anticodons (that bind to the codons on mRNA.
Has an amino acid binding site.
Whats the structure of a ribosomal RNA (rRNA)?
Contains hydrogn bonds
What are the differences between DNA and mRNA?
DNA:
- deoxyribose
- Thymine
- Long
- Double stranded
- Contains hydrogen bonds
mRNA:
- Ribose
- Uracil
- Short
- Single stranded
- Doesn’t contain hydrogen bonds.
What is DNA in prokaryotic cells compared to eukaryotic?
- DNA shorter
- Fewer genes
- DNA circular not linear
- DNA not associated with histones
- No introns present
- Sometimes additional plasmids.
Both :
- nucleotide structures identical and nucleotide joined by phosphodiester bonds.
What is the process of semi conservative DNA replication?
- DNA helicase breaks hydrogen bonds between complementary bases in 2 polynucleotide strands
- this gives singled stranded DNA with exposed bases, that can act as templates, determining order of nucleotides on newly synthesised strands.
- Free DNA nucleotides bind complementary bases on exposed strands (AT and CG) by hydrogen bonds.
- DNA polymerase forms phosphodiester bonds between adjacent nucleotides by condensation reaction.
- by semi conservative replication.
What enzymes are used in semi conservative DNA replication?
DNA helicase
DNA polymerase
