Mutations

Question 1

How do chromosomal mutations occur?

Answer 1

Loss of genetic material through the deletion of part or one or more chromosomes
Often lethal
Relocation of genetic material
inversion where one more more genes are inverted or order reversed
Can have serious consequences on how genes are regulated or expressed
Translocation
genes move to a no homologous chromosome
Duplication
Extra chromosomes are inherited
Gain in genetic material
Polyploidy
Watermelon and banana are triploid
Extra sets of chromosomes
3n, 4n, 6n, 8n (strawberries), and other
Lethal in animals
Many in crops

Question 2

What is Aneuploidy?

Answer 2

One fewer or one extra chromosome that is found in a germ cells due to non-disjuction which is the failure of chromosomes to separate properly in anaphase I or II of meiosis
Leads to one less or one more chromosome being inherited
Can be autosomal or sex chromosomes
Turner Syndrome
Occurs in the sex chromomes
Results in a monosomy- inheritance of one few chromosome
Characterized by just one X chromosome
Trisomy- one extra chromosome inherited 2n= 47
Down syndrome
Kleinfelter Syndrome
2n=48
Male inherits two or three X chromosomes from his mother
1:500 male furthers

Question 3

What is a point mutation?

Answer 3

Point mutations- changes to the nucleotide base sequence of a gene

Question 4

What are chromosomal mutations?

Answer 4

hances to the number of chromosomes or structure of a chromosome, often associated with meiosis

Question 5

What are mutagens?

Answer 5

Chemicals that cause mutations
At least fifty five carciogen chemical in tobacco snake transfer small hydrocarbon groups to the nucleotide bases in DNA
Many environmental pollutants are converted by the body to other compounds that bind irreversible to DNA replication errors that lead to mutations

Question 6

Explain how point mutations occur

Answer 6

Occur at gene level
Are transferred onward to the mRNA and protein
DNA->RNA-> protein (central dogma)

Question 7

What is Base Substitution

Answer 7

A for T

Question 8

What is Insertion?

Answer 8

Inserting one more nucleotides

Question 9

What is deletion?

Answer 9

One or more nucleotides bases absent from the gene

Question 10

What are Silent mutations?

Answer 10

If nothing happens when the above occur

Question 11

What are Frameshift mutation

Answer 11

reading frame of DNA, RNA, and aa chain is altered

Question 12

What are Mis-sense mutation

Answer 12

amino acid order disrupted, but still there is a chain that are laid down to produce a protein

Question 13

What are Non-sense mutations

Answer 13

protein synthesis is terminated early and the sequence is short