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Search > Learning Exercise Results > Biology: Chromosomal Defects

Learning Exercise: Biology: Chromosomal Defects

Biology: Chromosomal Defects
The Students will be able to apply the material learned in genetics to a true event. The students will learn that variations are necessary for the success of a population but not all mutations are favorable. The students will be cytogeneticists for a day in oder to determine the chromosomal defect of their patient. At the end the students will write a description of the defect including symptoms for their patient.
Course: Biology


Submitted by:
Braulia Sapien
Date Last Modified:
May 08, 2007


CONTENT OUTLINE: (Engagement by grouping students for an activity)  Review (15-20 min) o Systems and their functions o Body systems –Respiratory system, endocrine system, and reflex arc. o Organisms: the pig—levels of organization o DNA mutations—variations o The cell  Makes proteins—muscle, hair, nails  Use up energy and go through respiration  Cell division (2 ways) • Mitosis: occurs in somatic cells (body cells) and chromosomes replicate and cell divides to make 2 identical daughter cells . In humans, there are 23 pairs of chromosomes per cell – diploid • Meiosis: occurs in sex cells or gametes and chromosomes replicate once and divide twice to make 4 genetically different sperm in males and one egg in females the egg contains all organelles, sperm only used to transfer genetic material. In humans, there are 23 single chromosomes per gamete – haploid  Variety in chromosomes—Crossing over • Occurs during prophase I • Genes located near each other on a chromosome usually stay together-- hair color and eye color • Crossing over strengthens a species: changes in the environment • Not all variabilities are favorable o Students will be looking at chromosomal mistakes as a cytogeneticist in a laboratory. ACTIVITY: (55 min, 10-15 min for clean up and closure) Karyotyping Lab to look for chromosomal abnormalities and diagnosing the disease. PROCEDURES: 1. 15 minutes of lecture to review content and make connections from the beginning of the year to this date. 2. Pass out all the materials necessary for the lab. 3. Read the key points of the lab worksheet with the students in order to understand the process and the duty of the students. 4. Explain the steps and the use of each of the materials 5. Let the students work in pairs as I walk around observing and answering questions. 6. 10 minutes before the bell rings, have the students clean up and the karyotypes are put in a folder. 7. 5 minutes before the bell rings, give closure to the activity by questioning the purpose of the activity. Review key terms such as variability and its importance. MATERIALS 1. Patriot Cytogenetics Lab sheet 2. Chromosome smear sheet 3. Chromosome key 4. Patriot Cytogenetics Lab results sheet. 5. Patriot Cytogenetics Lab Doctor’s diagnosis sheet 6. Disease Flash cards. 7. Scissors 8. Glue Sticks 9. Folder ACCOMMODATIONS: My student with muscular dystrophy will be allowed to work with a partner to help her cut out the chromosomes. She is capable of gluing the chromosomes on to the results sheet. The activity is also set up to meet the needs of the students who are deaf. For the students who are English learners, I will explain the lab more in detail while the rest of the class works on the activity.



  • High School
  • Middle School


Genetics: Chromosomes, variation


Know the importance of variations in a population. Meiosis, Mendelian genetics, Monohybrid and Dihybrid crosses.

Learning Objectives

RATIONALE: To allow students make connections from class work to real-life events so they understand the importance of genetics as a daily event. The students can apply the information they have learned about segregation of chromosomes. Mutations lead to variation but they are not always favorable. OBJECTIVES: Students will be able to understand the connections between the material covered during the year and genetic variability and apply it to real-life situations.

Type of Task

  • Group
  • Individual
  • Student-centered
  • Supervised


EVALUATION The students should be able to determine the correct disease by the chromosomal abnormalities they found. Each chromosomal smear number has a different disease. Their understanding will be further evaluated by the answers on the Patriot Cytogeneics Lab Doctor’s diagnosis sheet. EL students are allowed to work with a student that can assist him or her understand the terminology

Technical Notes

Computer and projector to show chromosomal smears.