Genes and Proteins Flashcards
(23 cards)
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.
