Unit 1 Flashcards
Explain why the strands of DNA are described as anti parallel
Strands run opposite directions each end has a 5’end with phosphate and a 3’end with deoxyribose sugar
Describe key features of a DNA molecule
2 strands twisted into a double helix with the sugar phosphate backbone on outside and base pairs inside
DNA nucleotides joined together by weak hydrogen bonds between base pairing
Each strand had a 5’end with phosphate and a 3’end with deoxyribose sugar run antiparallel
The base sequence of DNA forms the genetic code
Describe how the DNA is organised in prokaryotes
They have circular chromosomes and some have smaller circular chromosome
Where linear chromosomes found
And where are circular chromosomes found
Nucleus of a eukaryote
Chloroplasts mitochondria of eukaryote and in prokaryotes
Histone protein
Used for packaging linear chromosomes
What enzyme is responsible for DNA replication and what does It need to start replication process
DNA polymerase
Needs primers
What is a primer
Short strand of nucleotide which binds at the 3’end of DNA template to add nucleotides
Why does DNA polymerase do
Adds DNA nucleotides using complementary base pairs to the deoxyribose 3’end of the new strand
What role does the enzyme Ligase have in this process
It joins fragments of DNA together on the lagging strand
What’s pcr used for
Technique that amplifies DNA using complementary primers for specific target sequences
Name enzyme that plays important role in pcr and it’s function
Heat tolerant DNA polymerase
Used to replicate region of DNA
List practical applications of pcr
Sole crimes ,settle paternity suits ,diagnose genetic disorders
Where is mRNA found in a cell and it’s job
Nucleus and cytoplasm
Carries a copy of the dna code from dna to ribosomes
3 base codons
Where is tRNA found in a cell and it’s job
Cytoplasm
Carries specific amino acid to the ribosome
3basses anti codon
Where is the rRNA found in a cell and it’s job
Cytoplasm
rRNA and proteins from the ribosomes
