Topic 4A - DNA, RNA And Proteinsynthesis Flashcards
What is a gene
A sequence of DNA that codes for either a polypeptide or a functional RNA
What is an intron
A segment of DNA or RNA molecule which doesn’t code for amino acids
What is an exon
The coding bit of a gene that codes for an amino acid
What are the 3 components of nucleotides
A pentose sugar, a phosphate group, an organic base
Describe the role of DNA
Carries genetic information, determines our inherited characteristics
Describe the structure of RNA
Ribose sugar
Phosphate group
A, C, U, G organic base
Single stranded
Describe the role of RNA
Transfers genetic information from DNA to ribosomes for Proteinsynthesis
What is the genetic code
The order of bases on DNA. Consists of codons.
Identify 3 features of the genetic code
Non-overlapping = each triplet is only read once
Degenerate = more than one triplet codes for the same amino acid
Universal = same bases and sequences used by all species
What is a gene
A sequence of bases on a DNA molecule that codes for a specific sequence of amino acids to make a polypeptide.
What is a locus
The fixed position on a DNA molecule occupied by a gene
What is a locus
The fixed position on a DNA molecule occupied by a gene
What is an allele
Different versions of the same gene
What is the genome
The complete set of genetic information contained in the cells of an organism
What is the proteome
The complete set of of proteins that can be produced by a cell
Describe the structure of mRNA
A long single strand. It’s base sequence is complementary to the DNA it was transcribed from.
Describe the structure of tRNA
Single strand of nucelotides folded into a clover shape. On one end is an anti codon and on the opposite end is an amino acid binding site
What is produced by transcription
mRNA
Where does transcription take place
In the nucleus
Outline the process of transcription
DNA uncoils into 2 strands with exposed bases. One used as a template.
Free nucleotides line up next to their complementary bases, and are joined together by RNA polymerase
What happens to mRNA after transcription
Must be spliced to leave the nucleus
What is produced by translation
Proteins
Where does translation take place
In cytoplasm on the ribosomes
Outline the process of translation
The anticodon of tRNA attaches to complementary bases on the mRNA
Amino acids bonded to tRNA to form peptide bonds, continuing to form a polypeptide chain until a stop codon is reached
Process requires ATP
What is the genetic code?
Sequence of base triplets in mRNA that code for a specific amino acid
(Base triplets dont share their bases - the code is non overlapping)
How can code be degenerate?
More possible combinations of triplets than there are amino acids
How can genetic code be universal ?
Same specific base triplets code for the same amino acids in all living things
