Genetic Disorders: Reading the Karyotype

Genetic Disorders: Reading the Karyotype

Year 10 Biology Understanding chromosomal abnormalities through karyotype analysis Duration: 45 minutes

WALT (We Are Learning To)

Understand what a karyotype is and how it's created Identify normal vs abnormal chromosome patterns Recognize common genetic disorders seen in karyotypes Explain how karyotyping helps diagnose genetic conditions

Success Criteria

I can define what a karyotype is I can count and identify chromosome pairs I can spot missing or extra chromosomes I can name three genetic disorders found through karyotyping I can explain why karyotyping is important in medicine

What is a Karyotype?

A picture of all chromosomes in a cell Chromosomes are arranged in pairs from largest to smallest Shows the complete set of genetic material Used to detect chromosomal abnormalities Normal humans have 46 chromosomes (23 pairs)

How Karyotypes Are Made

Normal Human Karyotype

22 pairs of autosomes (body chromosomes) 1 pair of sex chromosomes (XX or XY) Total = 46 chromosomes Each pair has the same size and shape Chromosomes are numbered 1-22 by size

Quick Check

How many chromosomes should a normal human have? What are the two types of chromosomes called? Which chromosomes determine if you're male or female?

Down Syndrome (Trisomy 21)

Extra chromosome 21 (3 instead of 2) Total chromosomes = 47 Most common chromosomal disorder Causes intellectual disability and physical features Can be detected before birth

Turner Syndrome

Missing one X chromosome in females Karyotype shows 45,X (only 45 chromosomes) Affects only females Causes short stature and infertility Can be treated with hormone therapy

Klinefelter Syndrome

Extra X chromosome in males Karyotype shows 47,XXY Affects only males Can cause tall stature and learning difficulties Often goes undiagnosed until adulthood

Comparing Genetic Disorders

{"left":"Down Syndrome: Extra chromosome 21, 47 total chromosomes, Affects males and females equally\nTurner Syndrome: Missing X chromosome, 45 total chromosomes, Only affects females","right":"Klinefelter Syndrome: Extra X chromosome, 47 total chromosomes, Only affects males"}

Karyotype Detective Activity

Work in pairs to analyze mystery karyotypes Count total chromosomes Look for missing or extra chromosomes Identify the genetic disorder Present your findings to the class