Mutations

This lesson covers:

  1. What 'DNA mutations' are 
  2. How mutations can arise 
  3. The possible consequences of mutations
  4. You do not need to know about insertion or deletion mutations, which is why the video finishes early, but feel free to watch on if you're interested 

What is a mutation?

A change in the way an organism looks

A change to the structure of an organisms cells

A change in the base sequence of DNA 

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True of false? Mutations can occur spontaneously in our cells, but certain factors can increase the risk.

True

False

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Which of the following can increase the risk of mutations?

(Select all that apply)

Carcinogens like those found in cigarette smoke 

A balanced diet

Ionising radiation such as x-rays and gamma rays

Regular exercise 

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Will exposure to ionising radiation always cause a mutation?

Yes

No

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one / two / three / four / five


A triplet, or a codon, is a set of bases which codes for amino acid.

three
one

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A mutation to one of the bases in DNA can change the that a triplet (codon) codes for. 

amino
acid

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What is the most likely result of a genetic mutation?

A significant advantage to the organism 

No significant change to the organism 

A significant disadvantage to the organism 

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Most mutations occur in _______________ .

Coding DNA

Non-coding DNA

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Non-coding DNA often controls the expression of coding DNA.


What does it mean for a gene to be expressed?

It's turned off, so the proteins it codes for will not be produced 

It's turned on, so the proteins it codes for will be produced 

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What happens in a substitution mutation?

An extra base is added into the sequence 

A base is deleted from the sequence 

One base in the sequence is replaced with a different base 

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Enzymes are proteins that speed up the rate of chemical reactions.


Describe how a change of one of the bases in the gene for an enzyme could affect the functioning of that enzyme. 

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