SBI3U Genetic Processes Problem Solving Question:
Specific Expectation:
D2.3 use the Punnett square method to solve basic genetic problems involving
monohybrid crosses.
1. In dinosours, gene (T) for sharp teeth is dominant over the gene (t) for dull teeth.
a. Cross a homozygous sharp toothed dinosaur with a homozygous dull-toothed
dinosaur to produce the F1 (first generation) offspring. What are the genotypes
and phenotypes of the resulting offspring?
Givens:
Genotypes of the parents: TT and tt
Dominant trait: sharp-teeth
Recessive trait: dull-teeth
Required: Genotype and phenotype of F1 offspring
Analysis: Cross Homozygous sharp-toothed (TT) with Homozygous dull-toothed (tt)
Solution:
T
T
Tt
Tt
Tt
Tt
t
t
Paraphrase:
100% of resulting F1 offspring will have a Heterozygous dominant (Tt) genotype, and
100% of them will have sharp-teeth.
b. Now cross two of the F1 generation of offspring from question 1a to produce the
F2 offspring. What are their genotypes and phenotypes?
Givens:
Genotypes of F1 offspring: Tt
Required: Genotype and Phenotype of F2 offspring
Analysis: Cross Heterozygous sharp-toothed (Tt) with Heterozygous sharp-toothed (Tt)
Solution:
T
t
T
TT
Tt
Tt
tt
t
Paraphrase:
25% of the F2 offspring will have Homozygous dominant (TT) genotypes, 50% will have
Heterozygous dominant (Tt) genotype and 25% will have Homozygous recessive (tt).
75% of the F2 offspring will have sharp-teeth and 25% will have dull-teeth.
SBI3U Cellular Biology Problem Solving Question:
Specific Expectations:
B2.2 Investigate the effect of various qualitative factors on the rate of diffusion of
molecules across a plasma membrane
B3.4 Explain the importance of various cellular processes in human systems
B2.1 Use appropriate terminology related to cellular biology, including but not
limited to: macromolecules, passive transport, active transport, catalyst, and fluid
mosaic model
1. A marathon runner collapses after running on a hot day. Although the runner
consumed adequate water along the route, blood testing showed that many of his
red blood cells had burst. Why was this the case? Provide a diagram to illustrate
what happened.
Analysis:
Review and understand key concepts:
1. The law of diffusion (the movement of particles from an area of higher concentration to an
area of lower concentration)
2. Two types of solutions:
Hypotonic (A solution which is more dilute ie. less solutes than the cytosol. The cell gains water
and swells.)
Hypertonic (A solution which is more concentrated ie. more solutes than the cytosol. The cell
loses water and shrinks.)
Solution:
The marathon runner is a case of a hypotonic
solution. The solute concentration is higher inside
of his red blood cells than the outside. This causes
water to move inside of the cells, causing them to
swell and burst.