Essential Biology 4.3 Theoretical Genetics
Due Date:
Student Name:
Candidate Number: 002171-
Blog resource: http://tinyurl.com/26unw7c
Click4Biology: http://tinyurl.com/62qztrs
Cite all sources using the CSE method (or ISO 690 Numerical in Word. Highlight all objective 1 command terms in
yellow and complete these before class. Highlight all objective 2 and 3 command terms in green – these will be
part of the discussions in class. After class, go back and review them.
Complete the self-assessment rubric before submitting to Moodle. Avoid printing this if possible.
1. Define the following:
Genotype
Gene expression
Phenotype
Dominant allele
Recessive allele
Codominant alleles
Homozygous
Heterozygous
Carrier
Mixed phenotype
Autosome
Sex chromosome
Gene locus
Monohybrid cross
Test cross
2. Outline the conventions for notation of genotypes, using one example of each:
Dominant/recessive alleles
Codominant alleles
Sex-linked traits
1. The allele for tall plants is dominant over the allele for dwarf plants.
a. State the possible genotypes of a tall plant.


b. Explain how a test cross could be used to determine the genotype of a tall plant.



Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 4.3 Theoretical Genetics
Due Date:
Student Name:
Candidate Number: 002171-
3. Mendel is known as the father of genetics for his extensive experimental work with peas and
different types of crosses.
a. Complete the punnet grid below to show the outcome of the monohybrid cross that results
in peas of different colours.
b. Complete the punnet grid below to show the possible outcomes of a cross between two
members of the F1 generation. Describe all genotypes produced.
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 4.3 Theoretical Genetics
Due Date:
Student Name:
Candidate Number: 002171-
4. Human ABO blood types follow a codominant inheritance pattern.
a. Describe what is meant by “some genes have multiple alleles.”

b. Complete the table below to show how blood type is inherited.
alleles
i
IA
IB
i
IA
IB
c. Highlight the genotype and phenotype which is an example of
codominance.
5. Complete this pedigree chart to show the inheritance of blood types in this
family.
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 4.3 Theoretical Genetics
Due Date:
Student Name:
Candidate Number: 002171-
6. Sickle cell is another example of codominance.
a. State the genotypes and phenotypes of these individuals.
HbAHbA
HbAHbs
HbsHbs
genotype
phenotype
b. Predict the phenotype ratios of offspring in the following crosses. Show all your working,
and set it out as expected. Take care with notation.
i.
Carrier mother with affected father
ii.
Affected father with unaffected mother.
iii.
Carrier mother with carrier father.
c. Explain how the prevalence of sickle cell in regions of Africa is an example of natural
selection in action.




A
B
C
D
E
d. The pedigree chart below shows a family affected by sickle cell:
i.
Deduce the genotype of each individual with a letter.
F
G
H
$
#
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 4.3 Theoretical Genetics
Due Date:
Student Name:
Candidate Number: 002171-
ii.
Calculate the likelihood of any further children produced by E and her # having
sickle cell anemia.
iii.
Male $ is healthy but of unknown genotype. Calculate the likelihood of any children
produced with female D having sickle cell anemia. Show all working.
7. Some traits are autosomal whereas others are carried on sex chromosomes.
a. Distinguish between autosomes and sex chromosomes.


b. Annotate the diagram to distinguish between the X and Y chromosomes.
c. Outline the role of the SRY gene on the Y chromosome.



d. Outline how non-disjunction can lead to gender-related chromosome abnormalities.



Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 4.3 Theoretical Genetics
Due Date:
Student Name:
Candidate Number: 002171-
8. Some inherited disorders are associated with gender.
a. Define sex-linkage.

b. State two examples of sex-linked genetic disorders.


c. Explain why sex-linked disorders are more common in males than females.




d. Explain why human females can be homozygous or heterozygous for sex-linked genes,
where males cannot.




e. The allele for colour blindness (n) is recessive to the allele for normal vision (N). This gene is
carried in a non-homologous region on the X chromosome. Complete the table below to
show the genotypes and phenotypes of individuals with regard to colour blindness.
Female
N
X X
Normal
Male
N
Affected
Not possible! Why?
Carrier
f.
In the space below, complete a punnet grid to show a cross between a normal male and a
carrier female. What is the expected ratio of phenotypes?
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 4.3 Theoretical Genetics
Due Date:
Student Name:
Candidate Number: 002171-
9. Hemophilia is a blood-clotting disorder that is also recessive and sex-linked.
a. State the normal function of the gene associated with hemophilia.

b. Describe the effects and symptoms of hemophilia.


c. Use the pedigree chart to deduce the possible genotype(s) of the named individuals.
Leopold
Helen
Alice
Mary
Rubert
Bob
Britney
d. Outline one form of genetic engineering used to help patients with hemophilia.





e. Suggest reasons why the frequency of some disease-related alleles might be increasing in
the population.


Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 4.3 Theoretical Genetics
Due Date:
Student Name:
Candidate Number: 002171-
Works Cited
1. Allott, Andrew. IB Study Guide: Biology for the IB Diploma. s.l. : Oxford University Press, 2007. 978-019-915143-1.
2. Mindorff, D and Allott, A. Biology Course Companion. Oxford : Oxford University Press, 2007. 978099151240.
3. Clegg, CJ. Biology for the IB Diploma. London : Hodder Murray, 2007. 978-0340926529.
4. Campbell N., Reece J., Taylor M., Simon. E. Biology Concepts and Connections. San Fransisco :
Pearson Benjamin Cummings, 2006. 0-8053-7160-5.
5. Taylor, Stephen. Science Video Resources. [Online] Wordpress, 2010.
http://sciencevideos.wordpress.com.
6. Burrell, John. Click4Biology. [Online] 2010. http://click4biology.info/.
7. IBO. Biology Subject Guide. [Online] 2007. http://xmltwo.ibo.org/publications/migrated/productionapp2.ibo.org/publication/7/part/2/chapter/1.html.
Self Assessment:
Essential Biology
Criterion
Presentation &
Organisation
Academic
Honesty
Objective 1
understanding
Objective 2
understanding
Objective3
understanding
Logic, notation,
mathematical
working
Further research
Assessment
Complete (2)
Partially complete (1)
NA
Complete and neat. All command terms
highlighted, tables and diagrams well presented.
Self
Sources cited using the CSE (ISO 690 numerical)
method, with Works Cited section complete and
correct.
All answers for the following command terms
Most answers for the following command terms
correct:
correct:
Define
Draw
Label
List
Measure State
Most answers for the following command terms
All answers for the following command terms correct:
correct:
Annotate Apply
Calculate Describe Distinguish Estimate Identify
Outline
Most answers for the following command terms
All answers for the following command terms correct:
correct:
Analyse Comment Compare Construct Deduce Derive Design Determine Discuss
Evaluate
Explain Predict
Show Solve
Sketch Suggest
Answers are presented in a logical and concise
manner. SI units used most times, with correct
NA
unit symbols and definitions of terms. All
mathematical working shown.
Evidence is apparent of research and reading
beyond the textbook and presentations to find
correct answers to challenging questions. If any
NA
questions are unanswered, this criterion scores
zero.
NA
Total (max 10):
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
MrT