Chromosome analysis lets geneticists directly observe chromosome number and structure rather than infer inheritance only from visible traits. This lesson introduces chromosome identification, karyotypes, and how a karyogram can reveal inherited disorders.
A karyotype describes the number and appearance of an individual's chromosomes, including their length, banding pattern, and centromere position. A karyogram, also called an ideogram, is the visual chart in which photographed chromosomes are arranged into pairs.
All flashcards
What is a karyotype?
A description of chromosome number and appearance, including chromosome length, banding pattern, and centromere position.
What is a karyogram?
A visual arrangement of photographed chromosomes, usually organized into homologous pairs and ordered by size.
What do p and q mean in chromosome location labels?
They designate the chromosome arms: p is the short arm and q is the long arm. Numbers specify regions along each arm.
Why are cells arrested in metaphase for karyotyping?
Chromosomes are condensed and easier to distinguish in metaphase, making them suitable for photographing and analysis.
What abnormalities can a karyogram detect?
It can reveal extra or missing chromosomes, large deletions, and visible structural changes such as translocations.
Quiz questions
What information does a karyotype describe?Answer: The number and appearance of chromosomes, including their length, banding pattern, and centromere position.
What is a karyogram?Answer: A chart displaying photographed chromosomes arranged into homologous pairs.
What chromosome complement is typically associated with Turner syndrome?Answer: One X chromosome, written X0.
Which features can help identify a chromosome in a stained karyogram?Answer: Its size, centromere position, and characteristic banding pattern.
A karyogram shows three copies of chromosome 21. What does this indicate?Answer: Trisomy 21, an aneuploidy involving an extra chromosome 21.
Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.