Variation

Question 1

Why sexually produced organisms vary in characteristics

Answer 1

Homologous Chromosomes show random segregation so daughter nuclei contain a mixture of paternal and maternal chromosomes

Homologous chromosomes cross over during Prophase 1 so daughter nuclei receive chromosomes that are a mixture of paternal and maternal segments

The segregation of sister chromatids is also random one chromatid can have a mixture of maternal and paternal DNA while the other does not

Random Fertilization- Different organisms can have different combinations of alleles for different traits

Question 2

What is the importance of genetic variation

Answer 2

Genetic variation means that some organisms within a population will have a necessary combination of genes that will make it better adapt to its environment. The organisms would then survive and pass on their alleles to the next generation. If conditions remain the same these alleles will become common. If conditions change new alleles would allow a better ability to survive over time. Genetic Variation ensures a subsection of the population would be able to survive without this variation changes in environmental conditions would completely wipe out populations.

Question 3

Mutation

Answer 3

Mutation- A permanent change in the nucleotide sequence of DNA. This can affect a single base pair or a wide region of the chromosome that affects multiple genes. Mutations are caused by errors in replication, exposure to radiation chemical mutagens or due to infections by viruses

Question 4

Gene Mutations- 3 types

Answer 4

Gene mutations is a permanent change of the DNA sequence within gene

Silent Mutation-change in DNA sequence nucleotide base pair that doesn’t result in a change in the amino acid incorporated in the protein

Nonsense Mutation- Change in the DNA sequence nucleotide base pair results in a stop codon that signals the premature termination of the protein

Missense Mutation- change in DNA sequence nucleotide base pair that that results in another amino acid being incorporated instead of the original.

Question 5

4 other types of mutations that occur in the gene

Answer 5

Insertion-The number of DNA bases within the gene are increased which results in a new protein being formed which may or may not carry out the processes of the original protein

Deletion-These are when the number of DNA bases within the gene is decreased.
This results in a different protein being formed. This new protein may or
may not be able to carry out the original function.

Duplication- This results when a piece of DNA is abnormally copied 1 or more times. This is a protein altering mutation

Frameshift Mutation- Changes in the bases cause differences in the way that codons in the frame are read. This causes a different amino acid to be incorporated which can severely impact the functionality of the protein.

Insertions/deletions that change the amount of DNA bases by multiples of 3 will not cause a frameshift mutation but may still affect the functionality of the protein.

Question 6

4 Chromosome Mutations

Answer 6

Deletion- Removal of chromosomal segment
Duplication-Repetition of chromosomal segment
Inversion-Reverses a segment within a chromosome
Translocation- Movement of a segment of a chromosome from one chromosome to another non-homologous chromosome