Topic 8A: Mutations Flashcards
What is a mutation?
Changes in the base sequence of DNA
What causes a mutation?
- errors in DNA replication
- environment?
How can the RATE of mutations be increased?
by using mutagenic agents
Name the types of mutations..
Deletion Addition Duplication Substitution Inversion Translocation
What is a substitution mutation?
When one or more bases are swapped for another
What is a deletion mutation?
When one or more bases are removed
What is an addition mutation?
When one or more bases are added
What is a duplication mutation?
When one or more bases are repeated
What is an inversion mutation?
When a sequence of bases is reversed
What is a translocation mutation?
When a sequence of bases is moved from one location in the genome to another
Which mutations cause a frame shift?
Addition
Deletion
Duplication
What effect does mutations have on a body?
- changes the aa acid sequence of a polypeptide
- alters tertiary structure
- changed 3D shape
- doesn’t work properly
- mention active site and catalyst when talking about enzymes
Some mutations can cause…
genetic disorders
What are genetic disorders?
inherited disorders caused by abnormal genes or chromosomes
An example of genetic disorder?
cystic fibrosis
Some mutations can increase the chance of have developing certain cancer like…..
BRAC 1 can increase the chances of developing breast cancer
What is a hereditary mutation?
- When the gamete contains a mutation for a genetic disorder
- or when a type of cancer is fertilised
- this will be present in the fetus
- mutations that are passed down in the offspring
Are all hereditary mutations harmful?
No-some are beneficial and drive evolution
Not all mutations affect the order of amino acids. Why?
Because the genetic code is degenerate. This means more than one DNA triplet codes for the same amino acid.
What is it called when the mutation doesn’t cause a change?
a silent mutation
What happens in an Addition mutation?
- causes a frame shift to the RIGHT
- changes the number of bases in DNA code
- triplet code is altered
What happens in a Deletion mutation?
- causes a frame shift to the LEFT
- changes the number of bases in DNA code
- triplet code is altered
What happens in a Duplication mutation?
- causes a frame shift to the RIGHT
- changes the number of bases in DNA code
- triplet code is altered
Mutations occur…
spontaneously
Name examples of mutagenic agents
- ultraviolet radiation
- ionising radiation
- some chemicals and viruses
How do mutagenic agents increase the rate of mutations?
- Act as a base
- Alters bases
- Changes the structure
How do mutagenic agents act as a base?
- Chemicals called “base analogs” can substitute for a base during DNA replication
- This changes the base sequence in DNA
Example of a base analog
- 5-bromouracil substitutes for thymine
- it pairs with guanine instead of adenine
- causes substitution mutation in new DNA
How do mutagenic agents alter the bases?
-some chemicals can delete or alter bases
Example of a mutagenic agent that alters bases
- alkylating agents can add an alkyl group to guanine
- this changes the structure
- pairs with thymine instead of cystosine
How do mutagenic agents change the structure of DNA?
- radiation can change the structure of DNA
- this causes problems in DNA replication
Example of a mutagenic agent that changes the structure of DNA
- UV Radiation
- causes adjacent thymine bases to pair up together
