1. Bell Ringer 4/15
Using the laws of codominance, predict the outcome of crossing a blue flower with a yellow flower. BB  Blue YY  Yellow Using the same information, predict the outcome under the rules of incomplete dominance.

2. Chromosomes and Karyotyes

3. Genetic Screening An examination of a person’s genetic makeup
Can be done in a fetus or a person already born
Looks at the DNA sequence or at chromosomes (a bunch of DNA and protein)
When doing genetic screening on a fetus, normally an amniocentesis is performed
Produces a picture of chromosomes of a fetus (can only diagnose some disorders)

4. Chromosomes Made of DNA and protein Found in the nucleus of a cell
Is chromatin that is coiled up

6. After DNA copies itself, the chromosome looks like this:
When the copies are attached to each other, each one is called a chromatid
Prokaryotes have only ONE main circular chromosome, no nucleus

7. Number of chromosomes in a cell
Diploid (2n) - two of each kind of chromosome in a cell
One from each parent
All body (somatic) cells in animals are diploid
Ex: skin, heart, muscle, stomach
In humans the diploid number is 46 (2n = 46)

8. Haploid (n) – one of each kind of chromosome in a cell
Only sex cells (gametes)
Sperm and egg
In humans, the haploid number is 23 (n=23)

9. Haploid + haploid = diploid
Sex cells have to be haploid because they join together to make a new organism
Haploid + haploid = diploid
Sperm egg = baby
= 46 =

10. Abnormal chromosome numbers
Nondisjunction
When the chromatids fail to separate during formation of gametes
This causes the sperm or egg cells to have an incorrect number of chromosomes

11. Two types of chromosomes
Sex chromosomes
X or Y
Determine if you are:
Male (XY)
Female (XX)
You have one pair of sex chromosomes, known as the 23rd pair
Autosomes
All other chromosomes
22 pairs in humans (44 total)

12. Karyotype  picture of chromosomes in a cell
Chromosomes are lined up in pairs (numbered 1-22) from longest to shortest
23rd pair (sex chromosomes) are always last
Often used for genetic screenings

13. Male

14. Female

15. Trisomy 21 = 3 of Chromosome 21 (Down Syndrome)

16. Monosomy = 1 chromosome

20. Karyotyping Links  Karyotyping
For each patient, you should have (to turn in):
The name of the karyotype
Number of chromosomes, XX or XY, any extra or missing chromosomes
Ex: 45,XY,-8
The patient’s diagnosis

21. Chromosomal Study You need:  Partner  Packet  Scissors  Glue Stick
Make two karyotypes
 Normal (male or female)
 Abnormal (male or female)
 After putting your karyotype together, research your genetic disorder to answer the questions on the handout.
Once your finish  Clean up!!!  Both names on paper  Unit Guide  Finish Blood Type Worksheet  Google Classroom assignment