Genes Flashcards
What is a gene?
A segment of DNA that can be transcribed and translated to be expressed as a protein
What is the structure of genes in a eukaryote?
promoter region - gene - terminator region
What is a promoter region in a gene?
A sequence of nucleotides that the RNA polymerase binds to in order to begin transcription
What is a terminator region in a gene?
A sequence of nucleotides that tell the RNA polymerase to stop transcription
What is an exon?
Coding regions (EXiting the nucleus)
What is an intron?
Non-coding region (remaining IN the nucleus)
Introns add resilience because mutations on them wont be expressed
What is the structure of genes in a prokaryote?
Promoter region - Operator region (switch, w a repressor molecule) - gene - terminator region
Why don’t eukaryotes have an operator region?
They have more complex mechanisms to turn off/on genes
What is an operator region and repressor molecule?
A repressor molecule can turn off the gene by binding to the operator, it changes shape to do so. One shape can bind on, the other can’t.
What is the purpose of an operator region?
Saves energy
Can be switched on to make food ect.
Is a codon in DNA?
No, only in mRNA
How does DNA get to protein?
DNA sequence
Transcribed to mRNA (RNA processing)
Translated to an A.A. sequence
What are the 4 features of genetic code?
Universality - same in all living cells
Unambiguous - 1 codon for 1 specific A.A.
Degeneracy - 20 A.A. but 64 codons
Non Overlapping - codons read in lots of 3 nucleotides that don’t overlap
What is RNA processing?
What is transcription?
the process whereby a sequence of DNA is used as a template to produce a complementary sequence of mRNA
What is translation?
the process where an mRNA sequence is read to produce a corresponding amino acid sequence to build a polypeptide
What differs DNA polymerase and RNA polymerase
DNA polymerase can copy the whole DNA sequence, while RNA polymerase only copies a small section
