Any1 up for helping me with mutations!?? Plzz

[Jenko13]

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Can someone plzz help me to answer/understand this question:

Explain the role that mutation has in evolution? Are all mutations beneficial, harmful or make no difference? (7marks)

I dont rlly understand wat a mutation is!??

[hamzie]

Mutations are the insertion deletion and substitution of nucleotides
Remember?

And they can be beneficlal though it is rare

sometimes they do not make a difference since more than one codon can code for the same thingy (i havent slept and the word isnt coming to me)

But theyll more likely be harmful - cancer

[k02033]

Mutations are changes in the DNA information on the chromosomes. Mutations arise from exposure to mutagens and incorrect DNA replications and transcriptions that does not get repaired (most do). There are 2 types of mutations, change in chromosome number and change in DNA base sequence. This results in new polypeptides formed since its made as instructed by the DNA base sequence. This new polypeptide forms new proteins which may change cellular structure and function and alter enzyme activity. This leads to new alleles and variations. If this mutation is not lethal and is advantagous and has occured in sex cells, it may be passed on to offsprings and slowly dominate and create a generation of new alleles in a population over time.

then insert a paragraph on natural selection to get 7 marks

[christoffpow]

Originally Posted by Jenko13

Can someone plzz help me to answer/understand this question:

Explain the role that mutation has in evolution? Are all mutations beneficial, harmful or make no difference? (7marks)

I dont rlly understand wat a mutation is!??

Well mutation are caused my mutagens. Mutagens alter the sequence of DNA or induce a mutation..

Mutations in DNA will lead to changes in the mRNA, (messenger RNA) in transcription, and therefore the polypeptide produced will be different. This 'different' polypeptide can then affect the functioning and structure of an organism.. for example. If a polypeptide (protein) is structural, then it could affect the structure of a body part, for example the shape of a birds beak.

Mutations lead to new Alleles. They are one characteristic that leads to variation in organisms.. thats what a mutation does.

They can be dangerous, neutral and advantageous. For example, some mutations in DNA sequence can cause sickle-cell anemia in humans, or make bacteria more resistant to antibiotics.

Often mutations are neutral, they have no advantages or disadvantages. Mutations only really show their true advantages/disadvantages to an organism when there is a major change in the external environment (natural selection comes in here).

Mutations however are an advantage that they are a source for new Alleles, thus are a source for variation in organisms. (in fact, the only source of variation in asexually reproducing organisms).

i just wrote a novel.. but this helps me to study so..

[samthebear]

Originally Posted by Jenko13

Explain the role that mutation has in evolution? Are all mutations beneficial, harmful or make no difference? (7marks)

Evolution is a theory based on the result of natural selection. Because natural selection operates on the assumption that all populations have varients, mutations provide the basis for variations within a population. Without mutations, there will be no variables for natural selection to act on. (eg: if there is an environmental change which negatively affects the organism, the whole species will be affected in equal measures. If one organism dies because of the new environment, the whole species will die too.)

Mutations can occur in somatic (body) and germline (gamete) cells. mutations occuring in germline cells have the potential to affect subsequent generations and mutations occuring in somatic cells affect the individual only and cannot be 'passed on' to off-spring.
Mutations are more often benign than beneficial or harmful, this is because all variations within a speices are considered mutations. variations such as eye colour, skin colour, hair colour are all considered mutations but are benign - that is there is no benefit nor harm from it.
However mutations occuring in the tumour suppressor gene may result in the uncontrolled growth of cells resutling in a tumour. In these cases, the tumour may become cancerous and in this case a mutation is harmful.
Mutations in itself does not become beneficial until environmental pressures indicate that the mutation is benefical in survival.*

*I cant think of any examples when a mutation is beneficial on its own (ie: it helps to extend your natural life expectancy, or it has an innate benefical nature.) if anyone can think of one please post.