Genetic Information, Variation and Relationships (DNA) Flashcards
(11 cards)
Define what is meant by a gene
A gene is a base sequence of DNA that codes for: the amino acid sequence of a polypeptide, or a functional RNA
Define what is meant by a locus
The position of DNA
Define what is meant by a proteome
Complete range of different proteins that a cell is able to produce
Define what is meant by introns
Non coding regions of DNA
Describe three words associated with genetic code
Universal - Has the same genetic code for all living organisms
Non - overlapping - each bade only appears in 1 triplet base sequence
Degenerate - more than 1 codon codes for an amino acid
Where does transcription take place
The nucleus
Describe the process of transcription (producing mRNA)
DNA helicase breaks the hydrogen bonds between complimentary base pairs to form a template strand
Free floating mRNA nucleotides are attracted to their complimentary base pair on the template strand. Adenine bonds to Uracil (not thymine) and cytosine bonds to guanine
mRNA polymerase joins adjacent nucleotides by forming phosphodiester bonds
This produces a single strand of pre mRNA
Introns (non coding regions) are spliced to form mRNA
Do you make pre mRNA in prokaryotic cells
No - transcription results directly in the production on mRNA from DNA
Where does translation take place
In the cytoplasm, within the ribosomes
Describe the process of translation (using mRNA to make proteins)
mRNA leaves the nucleus by the nuclear pores and attaches to the ribosome (or rough endoplasmic reticulum). There are only 2 codons at a time within the ribosome
tRNA brings a specific amino acid for its anticodon which binds to mRNA’s codon through complimentary base pairing
A peptide bond forms between the amino acids with the use of ATP
The tRNA is and the ribosome moves along for the next codon attached to it
This process repeats to form a polypeptide chain until you reach a stop codon
