Mutations

Question 1

nondisjunction

Answer 1

when a pair of homologous chromosomes fail to separate during meiosis. Results in 1 gamete getting 2 copies of chromosomes & the other gets none

Question 2

Aneuploidy

Answer 2

A chromosomal abnormality in which one or more chromosomes are present in extra copies or are deficient in number.

Question 3

monosomic zygote

Answer 3

has 1 copy of a particular chromosome after fert. (2n-1)

Question 4

trisomic zygote

Answer 4

3 copies of a particular chromosome after fert. (2n+1)

Question 5

Nondisjunction genetic disorders

Answer 5

associated with serious disorders in humans. Usually = spontaneous miscarriage or severe birth defects, some can be survived. Example = Down syndrome= aneuploidy involving 3 copies of chromosome 21

Question 6

Sex Chromosome Nondisjunction

Answer 6

Examples:
Turner Syndrome - XO monosomy
Klinefelter Syndrome - XXY trisomy

Question 7

Polyploidy

Answer 7

occurs when an entire set of chromosomes fails to separate.
Common in plants, not animals. Most modern foods = banana (3n - triploid), strawberry (8n - octaploid)

Question 8

Triploid

Answer 8

organisms have 3 sets of chromosomes (3n)

Question 9

Tetraploid

Answer 9

4 sets of chromosomes (4n)

Question 10

Breakage of Chromosomes

Answer 10

Cell will try to repair but if it goes wrong can lead to 4 outcomes.
Deletion (removes chromosome segment)
Duplication (repeats segment)
Inversion (reverses a segment in chromosome)
Translocation (moves segment from 1 chromos. to a nonhomologous chromos.)

Question 11

cri du chat syndrome

Answer 11

“cry of cat” in french. Results from specific deletion within human chromosome 5.
A child will be mentally impaired & has cat-like cry. Usually die in infancy or early childhood.

Question 12

Mutations

Answer 12

Changes in genetic material.

Question 13

Genome mutation

Answer 13

a nondisjunction (change in number of chromosomes)

Question 14

Chromosome mutation

Answer 14

a chromosome breakage (change in chromosome size/shape)

Question 15

Point mutation

Answer 15

changes in just 1 base pair.
3 types:
substitution of base pair
insertion of a base pair
deletion of base pair
Example =Sickle-cell hemoglobin.

Question 16

Codon

Answer 16

a unique sequence of 3 nucleotides of DNA or mRNA that specifies an amino acid or termination signal.

Question 17

Wobble position

Answer 17

3rd nucleotide in the codon sequence which is often interchangeable

Question 18

co-linear

Answer 18

Sequence of DNA coding strand tells us the sequence of the mRNA which in turn tells us the sequence of amino acids.

Question 19

Silent mutation

Answer 19

will have no effect on gene expression.

Question 20

nonsense

Answer 20

ends translation, truncated protein. Changes to a stop codon, usually a nonfunctional protein.

Question 21

missense

Answer 21

incorrect amino acids = altered protein

Question 22

Silent mutation: Substitution

Answer 22

Will change the codon but not the amino acids. Is silent & has no effect on amino acid sequence.

Question 23

Missense mutation: Substitution

Answer 23

Changes the codon which also changes the amino acids. Missense = causes altered protein.

Question 24

Nonsense mutation: Substitution

Answer 24

Changes the codon into a stop codon. Ends translation = truncated protein.,

Question 25

Insertion

Answer 25

mutation involving the addition of 1 or more nucleotide pairs to a gene. Alters the reading frame= frameshift mutation

Question 26

Deletion

Answer 26

A mutational loss of 1 or more nucleotide pairs from a gene. Usually, alter the reading frame = frameshift mutation.

Question 27

Spontaneous mutation

Answer 27

most common. Occurring in Eukaryotes ~ once every 2-12 x 10^ -6 times/ gene in a cell.
Occurs during DNA replication, recombination or repair (from DNA damage)

Question 28

Induced mutation

Answer 28

Caused by mutagens.

Question 29

mutagens

Answer 29

physical, and chemical agents such as radiation, carcinogens, and viral enzymes.

Question 30

germline mutations

Answer 30

mutations occurring in gametes and will affect an entire individual & carry on forward to the next generation.