Gene Mutation Flashcards

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1
Q

Define Mutation

A

a sudden change in the quantity and structure of the genetic material in the cell

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2
Q

Where does genetic diversity arise from

A

mutations

recombining of DNA of 2 individuals after meiosis/ binary fission

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3
Q

When are gene mutations most likely to occur?

A

In interphase

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4
Q

What are the three types of gene mutation

A

addition
substitution
deletion

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5
Q

Define chromosome mutation

A

changes in the structure and number of whole chromosomes

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6
Q

Name two types of chromosome mutation

A

polyploidy (more than 2 chromosomes)

non-disjunction (individual chromosomes don’t divide during meiosis)

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7
Q

What are all mutations?

A

chance mutations

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8
Q

Why are errors in DNA replication more damaging than an error in transcription?

A

The error may be inherited so many have a permanent effect unlike transcription

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9
Q

Name three mutagenic agent

A

UV Light
Ionising particle
carcinogenic

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10
Q

Describe how deletion mutation alters gene structure

A

causes frameshift

removal of 1 or more bases

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11
Q

How does deletion have a greater effect than substitution?

A

Deletion causes a frameshift and alters amino acid past deletion
Substitution causes only one changed substitution

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12
Q

Meiosis produces how many daughter cells?

A

4 with the haploid number of chromosomes

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13
Q

Describe what occurs in Meiosis 1

A

Homologous chromosomes pair up
chromatids wrap around each other
crossing over occurs
By the end, the homologous pairs have separated with one chromosome from each pair in each daughter cells

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14
Q

Describe what occurs in Meiosis 2

A

chromatids move apart 4 cells are formed

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15
Q

What happens in independent segregation?

A

homologous pairs line up at random so the combination of maternal and paternal chromosomes is by chance

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16
Q

What happens in crossing over ?

A

chromatids of each pair twist around one around another
parts of the chromatids break off and regions with homologous partner
to produce new gentic combinations

17
Q

What are the equations associated with this topic

A

2n ( hapliod number) 2n2

18
Q

Describe and explain the appearance of chromosomes in X form

A

2 sister chromosomes attached to the centromere

DNA replication has occurred

19
Q

What event happens in meiosis 2 not 1

A

the separating of sister chromatids

20
Q

Describe what happens to chromosomes in meiosis

A

X condense and associate into homologous pairs
x are attached to the centromere
x line up at the equator and spindle fibre pull them 2 opposite poles

21
Q

How does meiosis cause genetic variation and explain the advantage of variation to the species?

A
crossing gene
independent segregation of chromosomes is meiosis 1/2
some better adapted
to reproduce and pass on the alleles
allows for changing environment
22
Q

How can a hybrid be fertile?

A

the diploid number of chromosomes
gametes receive one copy of all generic information
chromosomes can form bivalents

23
Q

What is the role of the centromere in meiosis

A

joins the 2 sister chromatids

so they can be separated

24
Q

How have different alleles been produced?

A

crossing over and allele exchange between chromosomes

25
Q

Define genetic diversity

A

the total number of different alleles in a population

26
Q

A decrease in the population number affects genetic diversity how ?

A

genetic diversity decreases

reduced gene pool

27
Q

Sugar Beet was chosen by farmers how does this effect genetic diversity

A

reduce genetic diversity as allele has been chosen

28
Q

What are the two types of selection?

A

Directional and stabilising

29
Q

Explain how the mutation causes an increase in allele freq. in a population?

A

mutation produced allele
selection pressure
more likely to survive and reproduce
increase in allele in the population

30
Q

Give two ways doctors could use base sequences to compare different types of
HPV.

A

Compare (base sequences of) DNA;

Look for mutations/named mutations
(that change the base sequence);

Compare (base sequences of)
(m)RNA

31
Q

Explain how the chromosome number is halved during meiosis.

A

Homologous chromosomes (pair);
One of each (pair) goes to each (daughter)
cell / to opposite poles;

32
Q

Describe the process of crossing over and explain how it increases genetic
diversity

A

Homologous pairs of chromosomes associate
/ form a bivalent;
Chiasma(ta) form;
(Equal) lengths of (non-sister) chromatids /
alleles are exchanged;
Producing new combinations of alleles;