Genes - Lecture 3 Flashcards
What is intergenic DNA?
DNA between genes that are non-protein coding
What is the difference between exons and introns?
○ Exons: contain information to make a protein
○ Introns: information not needed to make a protein and make up the majority of a gene
How is the information in a gene used?
○ Transcribed into RNA
○ RNA is translated into a protein
What types of proteins are there?
○ Structural proteins
○ Motor proteins
○ Catalytic proteins (enzymes)
○ Transport proteins
○ Storage proteins
○ Protective proteins
○Regulatory proteins
What are the coding RNAs?
○ mRNA
○ Make up 4% of total RNA
What are the non-coding RNAs that are present in all organisms?
○ rRNA
○ tRNA
What are the non-coding RNAs that are not present in bacteria?
○ snRNA
○ snoRNA
○ scRNA
○ miRNA
○ siRNA
What is a simple multi-gene family?
All the genes are the same
Why are simple multi-gene families needed?
Needed when a gene product is needed in large amounts e.g. ribosomal RNA genes
What is a complex multi-gene family?
○ Genes are not identical but have similar DNA sequences
○ They code for similar but non-identical proteins
Why are complex multi-gene families needed?
Provides proteins with slightly different function which allows increased organismal complexity e.g. human globin genes
What are the gene families for the human globin genes?
○ α-globin genes on chromosome 16
○ β-globin genes on chromosome 11
○ Genes are expressed at different stages in human development
How do multigene families arise?
Gene duplication
What is the molecular clock?
○ A measure of the rate at which the sequence of a gene changes
○ The greater the time that has passed since duplication, the more differences seen between the pair of genes
○ Used to work out when a pair of genes were formed by duplication
What are pseudogenes?
○ Lost their function
○ They have changed in such a way that their nucleotide sequence no longer makes sense
