Term
| Name the three types of mutations possible |
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Definition
1. Point mutations (substitution)
2. Insertion/deletion
3. Large scale changes in chromosome structure
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Term
| What are point mutations (substitutions)? Give three types and their descriptions. |
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Definition
A substitution is when one base is replaced (on both strands).
Types:
1. Silent mutation - The base change results in the same amino acid product
2. Missense mutation - The base change results in a different amino acid
3. Nonsense mutation - The base change results in a stop codon product |
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Term
| What type of mutations do insertions and deletions cause? |
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Definition
| Unless there are three subsequent bases inserted or deleted, a freameshift mutation results. This causes completely different amino acid products. |
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Term
| What are four types of large scale chromosome changes? |
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Definition
1. Deletion - A segment of the chromosome is deleted
2. Duplication - A segment of the chromosome is duplicated
3. Inversion - A segment of the chromosome is reversed
4. Reciprocal translocation - Two segments of non-homologous chromosomes are switched |
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Term
| What is an operon? What type of organisms are operons found in? |
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Definition
| Operons are a set of genes whose proteins work together, along with a promotor and operator. They create one mRNA which codes for several proteins. Operons are found in bacteria (not in eukaryotes). |
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Term
| What is the difference between polycistronic and monocistronic mRNA? |
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Definition
| Polyscistronic mRNA (found in prokaryotes) codes for more than one protein. Monocistronic mRNA (found in eukaryotes) codes for one protein. |
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Term
| What role do repressor proteins play in relation to operons? |
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Definition
| Repressor proteins are regulatory proteins which bind to the operator of an operon when repressors bind to it. This prevents transcription. |
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