Chromosome Theory of Inheritance These puppies have the

Chromosome Theory of Inheritance These puppies have the same parents, but are they all the same?

In his November 1677 letter to the Royal Society, “de Natis e semine genital Animalculis, ” Anton van Leeuwenhoek describes a scene teeming with tiny “animalcules. ” Each possesses a blunt head and a long, nearly transparent tail. And they’re propelling themselves along, “moving like a snake or like an eel swimming in water. ” The role of the egg and the sperm was not understood at the time. Many thought that a tiny human lived in the sperm, and the uterus was just an incubator.

Chromosomes 1. Improved microscopes later reveal that each cell contains structures called chromosomes. The number of chromosomes depends on the species

2. Chromosomes come in matching sets -these are called homologous pairs The chromosomes are numbered by size, with one set being the sex chromosomes. XX = girl XY = boy Every cell of your body has 46 chromosomes.

3. When looking at the chromosomes of egg and sperm, it was discovered that they don’t have paired chromosomes, they only have HALF of what the body cells have. Human body cells have 46. How many chromosomes are in a human sperm cell? 23 How many sex chromosomes? 2

4. Homologs are the same size and have the same banding pattern. FIND THE HOMOLOG!

5. Cells in your body have a complete set (all 46) - they are called DIPLOID Sex cells (sperm and eggs) only have half (23) - they are called HAPLOID

1. DNA unwinds during: a) replication b) reproduction c) cytokinesis 2. A chromosome is made of two individual __________ 3. An image of all of your chromosomes is called a ______. 4. During what phase is a karyotype made? ______ 5. Sperm and egg are both called: _________ 6. A fertilized egg is called a: __________ 7. Which parent determines the sex of the baby? 8. A karyotype can reveal a genetic __________

6 b. Chromosome Structure

7. MEIOSIS = The process of creating gametes (sex cell) It is similar to mitosis, but will produce 4 daughter cells that are each haploid and unique.

8. Errors in Meiosis can result in the gamete having with an extra chromosome. Down syndrome is caused by the baby having an extra chromosome #21. https: //johnscrazysocks. com/

9. Karyotype Amniocentesis is a procedure fluid is taken from around the fetus and tested. A karyotype is a photo of the chromosomes arranged by size.

10. Karyotype Analysis What is wrong with this set of chromosomes? Is it a male or female? X X

11. Trisomy is when there is an extra chromosome in a set. Tri = three Trisomy #18 is Edward Syndrome Down Syndrome is Trisomy #21 Trisomy #18 is also called Edward Syndrome

12. GENES are located on chromosomes and control the TRAITS of the individual GENOTYPE = genetic code PHENOTYPE = appearance There is a gene for the curly hair seen on this golden doodle.

Include these words in your explanation: GAMETE ZYGOTE 13. TASK: Work together to develop an explanation for why a litter of puppies with the same parents can all look different.

14. What about identical twins?

1. The purpose of MEIOSIS is to: Quick Check a) create identical daughter cells b) create four unique cells for the purpose of reproduction c) create four new organelles to build new cells d) copy DNA so that cells can repair themselves 2. MEIOSIS only occurs in what type of cells? a) b) c) d) zygotes skin cells gametes mitochondria

Let's review terms. . . 3. Matching sets of chromosomes are called ____ pairs 4. Egg and sperm combine to make a ________ 5. Egg and sperm are both known as ________ 6. A cell that only has half of a set of chromosomes is _____. 7. A cell that has both sets of chromosomes is ____ 8. Genes are located on __________

Assignment: Construct a Karyotype Tasmanian Devil