LESSON 2 CH20 What are chromosomes? _______________________________________________________ What is the portion of chromosomes that makes each human unique to another? ________ What is the shape of this structure? __________________________________ Chromosomes: How many pairs do you have? __________ How many total ____________ What letter chromosome signifies a female __________ Male __________ Which parent determines the gender of the fetus? ______________ Why__________________________________________________________________ What are the structures in the chromosomes that carry our genetic traits? _____________ What are some examples of the genetic traits our genes deal with _________________ __________________ ___________________ How does this process of creating traits come about? ___________________________ ______________________________________________________________________ ****For each trait there are 2 genes, they can be called _______________ or ______________ Dominant Gene: ______________________________________________________________ Recessive Gene: _______________________________________________________________ Example: Each parent offers a gene for eye color… Let’s say that mom offers a gene for blue eye color and dad offers a gene for brown eye color. If the brown gene is dominant what color eyes would the offspring have? _____________________________________ How would you figure out the chances (roughly) that your child could have blue/brown eyes? First you would need to know what genes you carried for the trait (dominant/recessive homozygous/heterozygous…) In the area below take notes on homozygous/heterozygous for dominant or recessive traits and pennant squares. You will need to know this for the test, keep in mind there is actually much more that goes into deciding what traits an offspring has, this is the tip of the iceberg… Example: What are the chances these two have a child with brown eyes/Blue eyes? MOM: Bb DAD: BB B: Dominant gene for brown eye color b: Recessive gene blue eye color Answer: _________________________________ ________________________________________ ________________________________________ Example: What are the chances these two have a child with brown eyes/Blue eyes? MOM: Bb DAD: bb B: Dominant gene for brown eye color b: Recessive gene blue eye color Answer: _________________________________ ________________________________________ ________________________________________ ***We also may use this to determine probabilities that the offspring may end up with genetic disorder based on parent being a “carrier” of a recessive gene… How do you check for genetic disorders? 1) Amniocentesis: __________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 2) Ultrasound: ______________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 3) Chorionic Villi Sampling: __________________________________________________ ________________________________________________________________________ ________________________________________________________________________ Genetic Disorders: page 465/466 in your text. Sickle Cell Anemia: ___________________________________________________________ _____________________________________________________________________________ Phenylketonuria: _____________________________________________________________ _____________________________________________________________________________ Tay-Sachs Disease: ____________________________________________________________ _____________________________________________________________________________ Cystic Fibrosis: _______________________________________________________________ _____________________________________________________________________________ Down Syndrome: _____________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________