DNA And The Genome Flashcards
Structure of DNA
Nucleotides. Sugar phosphate backbone, A-T C-G, hydrogen bonds between bases. Double stranded antiparallel structure. Deoxyribose sugar and a phosphate. 3’ end abdominal a 5’ end. Double helix.
Prokaryotes have …..
A single circular chromosome and smaller circular plasmids
Eukaryotes have ….
Liner chromosomes tightly coiled and packed with histone proteins. They also have circular chromosomes in mitochondria and chloroplast. Yeast is special as it also has plasmids
What does DNA polymerase do in the replication of DNA?
Adds DNA nucleotides using complementary base pairing to the deoxyribose 3’ end of the new DNA strand. Ligament joins the strands together
What does RNA splicing do?
It forms the nature mRNA transcript
How is the phenotype determined?
By the proteins that are produced by gene expression
What is cellular differentiation?
The process by which a cell expresses a certain gene to produce a particular protein, which carries out a specific function
Embryonic stem cells are ….
Pluripotent
Tissue stem cells are….
Multipotent
Single gene mutations
Substitution
Insertion
Deletion
What can nucleotide substitutions lead to? (3 types of final results)
Missense- different amino acid produced
Nonsense- stop codon
Splice-site- some introns kept and some exons left out
Simple DNA replication
Double helix unwinds and hydrogen bonds break.
RNA primes join on the 3’ end. One on the leading strand and multiple on the lagging strand.
DNA polymerase adds nucleotides continuously on the leading and in fragments on the lagging.
Ligase then seals the sugar phosphate backbone together.
Components needed for PCR (5)
Buffer
Nucleotides
Primers
Polymerase and ligase
Template DNA
In PCR primers are…
Short strands of nucleotides which are complementary to specific target sequences.
Process of PCR
- Heated to 92-98* and the strands split
- Cooled to 50-65* primers attach to the single strands
- Heated to 70-80* heat tolerant DNA polymerase binds to primers and adds nucleotides to the 3’ end
- Heated to 92-98* again
- Cooled to 50-65* primers now bond to original fragments and copies
- Heated to 70-80* heat tolerant DNA polymerase copies the DNA again