MYTUTOR SUBJECT ANSWERS

158 views

How does a deletion of a base in the DNA base sequence lead to a mutated protein?

It is important to note that bases on the DNA (and mRNA) are read in separate sets of 3s along a DNA/(mRNA) stand (this is called a triplet code in DNA, or the codon in mRNA). So, if a base is deleted, the whole sequence undergoes a frame shift in which the base after the deleted one is read with the original group (E.g. ATTGCAC --> ATGCAC). This means that the triplet code (the set of 3 bases) is different. Note above how both triplet codes have been altered by this. This will happen to ALL the sequences following the deletion, so all those triplet codes will be altered and incorrect.

As the codon on the mRNA is transcribed from this altered DNA sequence, it will also have a different codon. The codon on the mRNA is translated into a polypeptide, with each codon of 3 bases coding to 1 specific amino acid. Hence, if the codon is wrong, the amino acid is wrong, so the polypeptide is wrong.

Polypeptides are long chains of amino acids strung together, and are folded into specific 3D shapes (the tertiary structure) to form a protein. They do this by forming hydrogen, ionic and/or disulphate bonds with the specific amino acids in the chain. If these amino acids aren’t there because a different one has been coded for by the mRNA due to the deletion in the DNA, then these bonds cannot form. Hence, the 3D shape will not be formed so the protein is not formed correctly, hence mutating it. 

Febi S. GCSE Biology tutor, A Level Biology tutor, GCSE Chemistry tut...

4 months ago

Answered by Febi, an A Level Biology tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

120 SUBJECT SPECIALISTS

£20 /hr

Catherine T.

Degree: BSc Medical Sciences with Professional Training Year (Bachelors) - Exeter University

Subjects offered: Biology, Science+ 3 more

Biology
Science
Human Biology
Extended Project Qualification
English Literature

“Aims and methods: I focus on breaking things down in to easy to digest pieces of information and will use a variety of methods to look at an aspect of your course. I will aim to make things clear and easy to remember, whilst also hopi...”

MyTutor guarantee

£26 /hr

Hannah G.

Degree: Chemistry (Other) - Liverpool University

Subjects offered: Biology, Science+ 1 more

Biology
Science
Chemistry

“First year Chemistry undergraduate, looking to help you achieve your full potential in Chemistry and Biology. ”

£20 /hr

ATHANASIOS T.

Degree: Law LLB (Bachelors) - Bristol University

Subjects offered: Biology, Law

Biology
Law

“I am Biological Science graduate and aspiring lawyer with an interest in science ethics and intellectual property. I am currently studying for my second degree at the University of Bristol law school. I have a passion for volunteering...”

MyTutor guarantee

About the author

Febi S.

Currently unavailable: for new students

Degree: Medicine (Bachelors) - Imperial College London University

Subjects offered: Biology, Maths+ 2 more

Biology
Maths
Chemistry
-Medical School Preparation-

“Hiya! I’m Febi, a first year medical student at Imperial College, offering to tutor Maths to GCSE and Chemistry and Biology to A level! I’m known to be friendly, encouraging and patient, qualities which I definitely bring to my tutori...”

You may also like...

Posts by Febi

How does a deletion of a base in the DNA base sequence lead to a mutated protein?

What are surds and how does multiplying them work?

You added 75cm^3 of 0.5moldm^-3 HCl to impure MgCO2, and some was left unreacted. The unreacted HCl reacted completely with 21.6cm^m of 0.5moldm^-3 NaOH. So what is the percentage purity of the MgCO3 sample?

Other A Level Biology questions

What is meant by the phrase saltatory conduction?

Outline the process of ATP synthesis in mitochondria.

Describe the structure of the cell membrane

Understanding HIV, vaccines and monoclonal antibodies

View A Level Biology tutors

Cookies:

We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok