4 DNA, genes and protein synthesis Flashcards
What is a gene?
A section of DNA that contains coded information for making polypeptides and RNA
What is a locus?
A section of DNA located at a particular position
How many bases code for one Amino Acid
3
The term used to describe when an amino acid is coded for by more than one triplet
Degenerate coding
Two features of the genetic code?
- Non-Overlapping
- Universal
What are exons?
Coding sequences
What are introns?
Non-coding sequences
Homologous pair
Two chromosomes that carry the same genes
Allele
An alternative form of a gene
Give examples of different alleles
ones for eye colour, hair colour, blood group etc.
Mutation
Changes in the base sequences that results in a different AA being > diff. polypeptide > protein.
Genome
Complete set of genes in a cell
The function of Messenger RNA
Transfers DNA from nucleus to cytoplasm.
What is each nucleotide composed of (three)
- Pentose sugar
- One of the organic bases
- Phosphate group
Structure of tRNA
- Small molecule
- Single-stranded chain folded into a clover leaf shape
- One end of the chain extends beyond the other so that the AA can easily attatch
Anticodon
Sequence of three opposing organic bases of those at the extended chain
In RNA, what does adenine pair up with?
Uracil
Transcription is the process of making what?
pre-mRNA
Process of Transcription
- Enzyme causes two strands of DNA to seperate to expose the bases
- The bases on one side of the DNA pair with its complemetary base that is within the nucleotide pool
- RNA polymerase moves along the strand and joins them together to form pre mRNA
What happens when the RNA polymerase reaches a stop codon?
pre-mRNA detatches and the process is complete
In eukaryotic cells what must occur to form mRNA?
Splicing
What is splicing?
Formation of mRNA. Introns are removed from the pre-mRNA so that only exons are left.
How does mRNA exit the nucleus?
Through the nucleus pore
