Unit 6: Chromosomal Abnormalities

Mutations that lead to cancer occur in only…

certain body cells

because cancer only occurs in certain body cells…

cancer starts in one part of the body

which cells will be affected if a mistake occurs in meiosis?

sperm and egg

karyotype

Picture of an organism’s chromosomes

Why in the karyotype do they have 2 of each chromosome

one if from the mom and one is from the dad

What is a karyotype notation?

Written as - total # of chromosomes: sex chromosomes: missing or extra (if any)

how does an organism acquire an extra or missing chromosome?

nondisjunction

nondisjunction

Chromosomes do not separate properly

when can nondisjunction happen?

during meiosis 1 or 2

deletion

a segment of a chromosome is removed

duplication

a segment of a chromosome is copied and inserted into the homologous chromosome

inversion

A segment of a chromosome is removed and then reinserted opposite to its original orientation (flipped)

reciprocal translocation

segments of 2 non-homologous chromosomes swap locations with each other

what is more harmful, chromosomal mutation or nucleotide mutations?

chromosomal mutations, as it involves several nucleotides and possibly multiple genes!