Genes and Proteins Flashcards
How are proteins made up?
From chains of amino acids called polypeptides.
How are amino acids held together?
By hydrogen bonds and molecular interactions.
What determines a protein’s function?
The three-dimensional shapes of the protein’s molecules.
What are the functions of proteins?
- Acting as structural unit.
- Enzymes
- Hormones
- Antibodies
What are mutation?
Random changes in genetic information.
Mutations can result in the alteration of what?
Genes or chromosomes.
What does the mutation of a gene result in?
No protein or an altered protein being expressed.
What is a single gene mutation?
A mutation that affects DNA nucleotide sequences.
What are the three types of single gene mutations?
- Deletion
- Insertion
- Substitution
What are the subcategories of substitution mutations?
- Missense
- Nonsense
- Splice-site mutations
What do nucleotide insertions or deletions result in?
Frameshift mutations or expansion of a nucleotide sequence repeat.
What can be altered by mutations of regulatory
sequences ?
Gene expression
What can be altered by splice-shift mutations?
Post-transcription processing.
What are chromosome mutations?
Alterations to the structure of a chromsome.
What are the types of chromosome mutations?
- Duplication
- Deletion
- Translocation
- Inversion
What do nonsense mutations result in?
A premature stop codon being produced which results in a shorter protein.
What do splice- site mutations result in?
Some introns being retained and/or some exons not included in the mature transcript.
What do frame-shift mutations result in?
All of the codons and all of the amino acids after the mutation being changed. This has a major effect on the structure of the protein produced.
What is duplication?
Where a section of a chromosome is added from its homologous partner.
What is deletion?
Where a section of chromosome is removed.
What is inversion?
Where a section of chromosome is reversed.
What is translocation?
Where a section of a chromosome is added to a chromosome, not its homologous partner.
What can these substantial changes result in?
The mutations being lethal.
