Name _________________________________________________
Date _______________
Period ______
Fertilization of Two Gametes – Review of Meiosis and Genetics.
Fertilization is the union of two gametes, egg and sperm to form a zygote, or fertilized egg. Fertilization
restores the original number of chromosome pairs and reshuffles the genetic information, allowing for
variation among offspring.
1. Find another gamete in the room to “mate” with.
2. Tape your two gametes here:
Sperm
Egg
3. Show the union of the two gametes during fertilization and the total number of chromosomes in the zygote. Be sure
to draw the alleles on the chromosomes.
4. Recall from your earlier experience:
Trait
Eye Color
Ear Lobe
Tongue Rolling
PTC Taster
Blood Types
Phenotype
(Variant of Trait)
Pigmented (Brown/Black)
Non-Pigmented (Blue)
Attached
Free
Can Roll
Cannot Roll
Can Taste PTC
Cannot Taste PTC
A protein receptors
B protein receptors
AB protein receptors
O no protein receptors
Symbol
B
b
A
a
R
r
N
n
A
B
AB
O
Describe the combination of the alleles that make your zygote:
Genotype:
Phenotype:
Picture of your baby:
Name _________________________________________________
Date _______________
Period ______
Analyzing genotype and phenotype are related for blood types, an example of co-dominance: Co-dominance is a cross
between organisms with two different phenotypes produces offspring with a third phenotype in which both of the
parental traits appear together.
Blood Types: Distinct molecules called agglutinogens (a type of antigen) are attached to the surface of red blood cells.
There are two different types of agglutinogens, type "A" and type "B". Each type has different properties. The ABO blood
type classification system uses the presence or absence of these molecules to categorize blood into four types.
Type A blood cells are covered with A agglutinogens, type B have B
agglutinogens, type AB have both A and B, and type O blood have none.
Blood Type Is Determined Genetically: The A and B antigen molecules on the surface of red blood cells are made by
two different enzymes. These two enzymes are encoded by different versions, or alleles, of the same gene. The A allele
codes for an enzyme that makes the A antigen, and the B allele codes for an enzyme that makes the B antigen. A third
version of this gene, the O allele, codes for a protein that is not functional; it makes no surface molecules at all.
Everyone inherits two alleles of the gene, one from each parent. The combination of your two alleles determines your
blood type.
The table on the left shows all of the possible combinations of blood type
alleles. The blood type for each allele combination is shown on the right. For
example, if you inherit a B allele from your father and an A allele from your
mother, your blood type will be AB.
5. Based on your alleles for blood type, draw a picture that shows how the DNA, Genes, and Proteins are related. Use
our protein model work from earlier to help get you started. Be sure to
a. Draw ALL your chromosomes and label with the correct alleles
b. Clearly identify how the genotype is related to the phenotype
Ribosome
Nucleus
6.
If blood type is co-dominant, what do you think incomplete dominance is? Find out and provide an example. (pg
511 in blue biology book at home)