Studied by 21 people
What are variations or changes in DNA?
Mutations
How do mutations happen?
An incorrect base is inserted or a base is skipped during transcription
Mutations can involve changes in the…
Sequence of nucleotides in DNA, or the number or structure of chromosomes.
What are mutations that change a single base pair?
Point mutations
Point mutations usually involve a…
Substitution
What is it called when one base is changed?
A substitution
A mutation that would cause translation to stop before the protein is finished is called a…
Nonsense mutation
Mutations in which one or many bases are inserted or removed from the DNA sequence are called…
Insertions and deletions
What are insertions and deletions also called?
Frameshift mutations
What are the four types of chromosomal mutations?
Deletion, duplication, inversion and translocation
Which chromosomal mutation results in the loss of all or part of a chromosome?
Deletion
Which chromosomal mutation produces an extra copy of all or part of a chromosome?
Duplication
Which chromosomal mutation reverses the direction of parts of a chromosome?
Inversion
Which chromosomal mutation results in part of one chromosome breaking off and attaching to another?
Translocation
Do all mutations affect an organism?
No
What are chemical or physical changes in the environment?
Mutagens
What are some examples of chemical mutagens in our world?
Pesticides, plant alkaloids, tobacco smoke, and environmental pollutants.
What are some examples of physical mutagens in our world?
X-rays, magnetic radiation & UV light.
A gene located on a sex chromosome is…
A sex-linked gene
Why is colorblindness more common in males?
Because the genes for color vision are on the X chromosome. For females to be colorblind, they need to be double recessive.
What do most female cells do with the extra X chromosome?
They inactivate it
The deactivated X chromosome is called a…
Barr body
How do calico cats have their differing fur colors?
The two X chromosomes with fur color genes are “switched off” differently in different parts of the body
How can a pedigree be used?
To analyze the pattern of inheritance followed by a particular trait.
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