Topic 2 - Nucleotides and nucleic acid Flashcards
DNA and RNA are both (1)
1 - polynucleotides
What is the basic structure of a nucleotide
Phosphate group (circle) bonded to pentose sugar (pentagon) bonded to organic base (rectangle)
DNA vs RNA
Number of strands
DNA - two antiparallel strands
RNA - one strand
DNA vs RNA
Length
DNA - Very long
RNA - Relatively short
DNA vs RNA
Pentose sugar
DNA - Deoxyribose
RNA - Ribos
DNA vs RNA
Nitrogenous bases
DNA - Adenine, Cytosine, Guanine and thymine
RNA - Adenine, Cytosine, Guanine and Uracil
DNA vs RNA
Function
DNA - Store genetic information
RNA - Transfer genetic information and forms ribosomes with proteins
What are polynucleotides made up of, what reactions are involved and what bonds
Polynucleotides are polymers made up of many nucleotide monomers joined together by a series of condensation reactions, forming phosphodiester bonds.
What is the DNA double helix head together by
Hydrogen bonds between complementary base pairs
How many hydrogen bonds are there between complementary base pairs
2 hydrogen bonds between A & T
3 hydrogen bonds between C & G
What is semi conservative replication
Semi conservative replication is the method in which DNA replicates, creating two molecules of DNA that consist of one original DNA strand and one newly synthesised DNA strand
Describe the process of semi conservative replication
DNA helicase breaks H bonds between the two strands
Free nucleotides complementary base pair to the exposed strands
DNA polymerase catalyses condensation reactions to join adjacent nucleotides, forming phosphodiester bonds.
Draw the structure of ATP
3 phosphate groups (circle) bonded to a ribose sugar (pentagon) bonded to an adenine (rectangle)
ATP -> ADP vs ADP -> ATP
Reaction type
ATP -> ADP - Hydrolysis
ADP -> ATP - Condensation
ATP -> ADP vs ADP -> ATP
Enzyme involved
ATP -> ADP - ATP hydrolase
ADP -> ATP - ATP synthase
ATP -> ADP vs ADP -> ATP
Energy profile of reaction
ATP -> ADP - release energy
ADP -> ATP - requires energy
During which processes can the condensation of ADP to form ATP occur
Respiration and photosynthesis
Describe DNA molecules in prokaryotes and their association with proteins
In prokaryotic cells, DNA molecules are short, circular and not associated with proteins.
Describe DNA in eukaryotes
In eukaryotes, the nucleus contains very long, linear DNA molecules associated with proteins, called histones. Together a DNA molecule and its associated proteins form a chromosome.
Which organelles in eukaryotic cells also contain DNA
The mitochondria and chloroplasts of eukaryotic cells also contain DNA which, like the DNA of prokaryotes, is short, circular and not associated with protein.
What is the genome
The genome is the full set of DNA found in an organism.
What is the proteasome
The proteasome is the full range of proteins that can be synthesised from the genome.
What is a gene
A gene is a section of DNA that code for polypeptides and functional RNA and are located at a fixed locus on a DNA molecule.
What is a sequence of 3 DNA bases
A sequence of three DNA bases, called a codon, codes for a specific amino acid. The genetic code is universal, non-overlapping and degenerate.
What is a section of DNA that codes for polypeptides called
Introns
What is a section of DNA that codes for amino acid sequences called
Exons
What is transcription
Transcription is the process of making messenger RNA from a DNA template.
Describe the process of transcription
DNA helicase breaks the hydrogen bonds between the DNA helix, free RNA nucleotides base pair with the exposed DNA template strand,
In prokaryotes, transcription results directly in the production of (1) from DNA.
1 - mRNA
In eukaryotes, transcription results in the production of (1)
1 - pre-mRNA; this is then spliced to form mRNA
What is translation
Translation is the process of making proteins by forming a specific sequence of amino acids based on coded instructions in mRNA
Describe the process of translation
RNA polymerase catalyses phosphodiester bonds between adjacent RNA nucleotides and the mRNA strand detaches, allowing the DNA helix to reform.
mRNA attaches to a ribosome on the rough endoplasmic reticulum, tRNA carries the corresponding amino acid to each codon on the mRNA one at a time, with an enzyme catalysing the formation of a peptide bond between amino acids using ATP, until a stop codon is reached and the peptide is released, folding into its tertiary structure.
