IB HL Biology I – Genetics Practice #1     Name: _______________________________ Block: ___
1.	Describe the consequence of a base substitution mutation with regards to sickle cell anemia. (4 marks)
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2.	Which response describes the behaviour of chromosomes in metaphase I and anaphase II of meiosis? (2 marks) 
	Metaphase I	Anaphase II	
A.	Chromosomes line up at the equator	Separation of homologous chromosomes	
B.	Tetrads (bivalents) line up at the equator	Separation of homologous chromosomes	
C.	Chromosomes line up at the equator	Separation of sister chromatids	
D.	Tetrads (bivalents) line up at the equator	Separation of sister chromatids	
3.	(a)	State the names of the parts of the chromosome labelled (i) and (ii) on the diagram below. (2 marks)

(b)	Explain how the inheritance of chromosome 21 can lead to Down’s syndrome. (3 marks)
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 (c)	Explain how meiosis promotes variation in a species. (2 marks)
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4.	Karyotyping involves arranging the chromosomes of an individual into pairs.  Describe one application of this process, including the way in which the chromosomes are obtained. (4 marks)
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5.	What is a possible consequence of two base substitution mutations occurring in the same gene? 
A.	Two amino acids coded for by the gene are changed.
B.	Amino acids in two polypeptides coded for by the gene are changed.
C.	All of the codons between the two mutations are changed.
D.	All of the codons from the first mutation onward are changed.
6.	Which characteristics are used to identify chromosomes when constructing a karyotype?
I.	The length of the chromosome.
II.	The position of the centromere on the chromosome.
III.	The pattern of bands on the chromosome.
IV.	The position of the chromosome on the spindle.
A.	I only
B.	I and II only
C.	I, II and III only
7.	What fluid is sampled to try to detect chromosomal abnormalities in a fetus? (1 marks)
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8.	The diagram below shows a cell undergoing meiosis. Outline the stage of meiosis? (1 marks)

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9.	What can be concluded on the basis of the following karyotype? (3 marks)

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HL IB Biology I: Genetics Practice #2 				Name: _________________________
1.	Define sex linkage and state one example. (2 marks)
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2.	The diagram below shows the pedigree of a family with red green colour-blindness, a sex-linked condition.

(a)	Deduce, with a reason, whether the allele producing the condition is dominant or recessive. (2 marks)
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(b)	(i)	Determine all the possible genotypes of the individual in the 2nd generation, using appropriate symbols.
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 (ii)	Determine all the possible genotypes of the individual in 3rd generation, using appropriate symbols.
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3.	The following diagram represents a two generation pedigree showing blood groups from one generation. 

(a)	Define the term co-dominant alleles. (1 mark)
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 (b)	Deduce with a reason the probable phenotypes and genotypes of the 2nd generation offspring if their father was 1st generation-1.
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 (3)
(c)	Deduce with a reason the probable phenotypes and genotypes of the 2nd generation offspring if their father was 1st generation-3
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(3)

4.	If a man has blood group O and a woman has blood group AB, what are the possible phenotypes and ratios of the offspring? 
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5.	A parent organism of unknown genotype is mated in a test cross. Half of the offspring have the same phenotype as the parent. What can be concluded from this result? 
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6.	Outline which process results in the greatest genetic variation in a population? (2 marks)
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7.	Outline one example of inheritance involving multiple alleles. (2 marks)
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8.	Hemophilia is caused by an X-linked recessive allele. In the pedigree shown below, deduce with a reason which individuals in the pedigree must be carriers of hemophilia?

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 (Total 4 marks)

IB HL Biology I – Genetics Practice #3       Name: ______________________________ Block: ____
_____1.	 If a man has blood group O and a woman has blood group AB, what is the probability that their child will be blood group O?
A.	0%
B.	25%
C.	50%
D.	100%
_____2. A parent organism of unknown genotype is mated in a test cross. Half of the offspring have the same phenotype as the parent. What can be concluded from this result?
A.	The parent is homozygous dominant for the trait.
B.	The trait being inherited is polygenic.
C.	The parent is heterozygous for the trait.
D.	The parent is homozygous recessive for the trait.
_____3. 	A cell replicates its DNA and then starts to divide by meiosis. What is the expected arrangement of chromosomes if crossing over has taken place between the two genes shown?

4.	(a)	Define the term sex linkage.
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 (1)
(b)	A male and female with normal colour vision each have a father who is colour blind. They are planning to have children. Predict, showing your working, the possible phenotypes and genotypes of male and female children.

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(3)

(c)	Explain the relationship between Mendel’s law of segregation and meiosis.
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 (3)
(d)	Distinguish the differences between animal cells and plant cells undergoing mitosis and cytokinesis.
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 (2)
5.	(a)	Annotate a simplified structure of a nucleotide.
(2)

A genetic cross was made between pure-breeding snapdragon plants with red flowers and pure-breeding snapdragon plants with white flowers. The cross produced F1 offspring that had only pink flowers. When the F1 plants were self-pollinated, the resulting F2 generation had some red, some white and some pink flowers.
(b)	(i)	Identify the relationship between the red and white alleles for flower colour. (1) 
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 (ii)	Deduce the genotype of the F1 plants. (1)
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 (iii)	Construct a Punnett grid to show the cross between two F1 plants.
(2)
(iv)	Deduce the proportion of the different phenotypes of the F2 offspring. (1)
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 (c)	Discuss two advantages of genetic screening. (2) 
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6.	A boy inherited red-green colour-blindness from one of his grandfathers. Deduce, giving your reasons, which of his two grandfathers was also colour-blind.
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(3)
7.	The following sequence of pictures, made using an electronic imaging technique, shows a cell undergoing division.

(a)	State the stage of mitosis typified by image II...........................................................................
(1)
(b)	List two processes that involve mitosis.
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(2)
(c)	State the process that results in tumour (cancer) formation or development.
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(1)
(d)	Explain, using one example, how non-disjunction in meiosis can lead to changes in chromosome number.
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(2)
8.	The ACHOO syndrome is an inherited condition that leads to sneezing in response to bright light and is hypothesized to be inherited in an autosomal (not sex-linked) dominant fashion. The following is a pedigree chart that shows three generations from one family.
		
	[Source: “Autosomal dominant pedigree chart. In Autosomal Dominance the chance of receiving and expressing a particular gene is 50% regardless of the sex of parent or child.” Jerome Walker. 22 July 2006.]
	If the ACHOO syndrome is inherited as an autosomal dominant condition, what is the probability that a heterozygous father and an unaffected mother produce an unaffected child?
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(2)
9.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Describe the causes of Down syndrome.
(5)
(b)	Describe how human skin colour is determined genetically.
(5)
(c)	Explain the causes of sickle-cell anemia.
(8)
(Total 20 marks)
10.	(a)	Define the term polygenic inheritance.
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(b)	Explain, using a named example, how polygenic inheritance gives rise to continuous variation.
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(c)	Describe the inheritance of colour blindness in humans.
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(3)
_____11.	Which of the following genotypes is possible in the offspring of a homozygous male with blood group A and a female with blood group B?
A.	IAIA
B.	IAi
C.	ii
D.	IBi
_____12.	A man of blood group A and a woman of blood group B have a child. If both are heterozygous for the gene, what are the chances of them having a child with blood group B?
A.	0%
B.	25%
C.	50%
D.	75%
IB HL Biology I –  Genetics Practice #4       Name: ______________________________ Block: ____
1.	In Zea mays, the allele for coloured seed (C) is dominant over the allele for colourless seed (c). The allele for starchy endosperm (W) is dominant over the allele for waxy endosperm (w). Pure breeding plants with coloured seeds and starchy endosperm were crossed with pure breeding plants with colourless seeds and waxy endosperm.
(a)	State the genotype and the phenotype of the F1 individuals produced as a result of this cross.
genotype	.............................................................................................................................
phenotype	.............................................................................................................................
(2)
(b)	The F1 plants were crossed with plants that had the genotype c c w w. Calculate the expected ratio of phenotypes in the F2 generation, assuming that there is independent assortment. Use the space below to show your working.

	Expected ratio	.....................................................................................................
(3)
	The observed percentages of phenotypes in the F2 generation are shown below.
coloured starchy	37%	colourless starchy	14%
coloured waxy	16%	colourless waxy	33%
	The observed results differ significantly from the results expected on the basis of independent assortment.
(c)	State the name of a statistical test that could be used to show that the observed and the expected results are significantly different.
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(1)
(d)	Explain the reasons for the observed results of the cross differing significantly from the expected results.
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(2)
2.	(a)	(i)	Define allele............................................................................................................................
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(ii)	Outline the consequences of a base substitution mutation. (2) 
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 (b)	(i)	Mendel crossed tall, round-seeded plants with short, wrinkled-seeded plants.
All F1 produced were tall, round-seeded plants. When F1 plants were crossed with other F1 plants, the F2 generation produced many more than 1/16 short, wrinkled-seeded plants. Deduce, with reasons, the inheritance of these genes.
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(ii)	The same cross was later repeated but gave fewer F2 short, wrinkled-seeded plants although still more than 1/16. Outline a named statistical test that could indicate if your deduction about the inheritance of these two genes is likely to be correct.
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 (2)
3.	(a)	Define sex linkage.
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(1)
(b)	State one example of sex linkage.
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(1)
(c)	Draw a simple pedigree chart that clearly shows sex linkage in humans. Use conventional symbols. Start with an affected woman and an unaffected man.

(4)

4.	(a)	Define the term co-dominance.
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 (1)
(b)	A man of blood type AB and a woman of blood type B are expecting a baby. The woman’s mother had blood type O. Deduce the possible phenotypes of the offspring from the cross shown below.

(4)
5.	A gene in humans called APC is located on chromosome 5. This gene controls cell division and is known as a tumour suppressor gene. Mutations of APC cause a genetic disease called FAP (Familial Adenomatous Polyposis).
(a)	State, with a reason, whether FAP is a sex-linked genetic disease or not. (1)
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50% of the gametes produced by a person with FAP have an APC gene with the mutation.
(b)	Identify, with a reason, whether FAP follows a dominant or recessive pattern of inheritance. (2) 
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_____6.	A gene in cattle controls whether horns develop or not. When cattle without horns are mated together, none of the offspring ever has horns. A male with horns is mated with females without horns. If half of the offspring have horns and half do not, what is the conclusion?
A.	The male is homozygous dominant.
B.	The male is homozygous recessive.
C.	The male is heterozygous.
D.	Only males have horns.
_____7.	In Drosophila the allele for normal wings (W) is dominant over the allele for vestigal wings (w) and the allele for normal body (G) is dominant over the allele for ebony body (g). If two Drosophila with the genotypes Wwgg and wwGg are crossed together, what ratio of phenotypes is expected in the offspring?
A.	9 × normal wings, normal body : 3 × normal wings, ebony body : 3 × vestigal wings, normal body : 1 × vestigal wings, ebony body
B.	3 × normal wings, normal body : 3 × normal wings, ebony body : 3 × vestigal wings, normal body : 1 × vestigal wings, ebony body
C.	3 × normal wings, normal body : 1 × normal wings, ebony body : 3 × vestigal wings, normal body : 1 × vestigal wings, ebony body
D.	1 × normal wings, normal body : 1 × normal wings, ebony body : 1 × vestigal wings, normal body : 1 × vestigal wings, ebony body
_____8.	What are the possible outcomes of recombination?
	I.	A different combination of unlinked genes not seen in the parents
II.	A different combination of linked genes not seen in the parents
III.	The same combination of genes seen in the parents
A.	I and II only
B.	I and III only
C.	II and III only
D.	I, II and III

9.	(a)	A farmer has rabbits with two particular traits, each controlled by a separate gene. Coat colour brown is completely dominant to white. Tailed is completely dominant to tail-less. A brown, tailed male rabbit that is heterozygous at both loci is crossed with a white, tail-less female rabbit. A large number of offspring is produced with only two phenotypes: brown and tailed, white and tail-less, and the two types are in equal numbers.
(i)	Deduce the pattern of inheritance of these traits.
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(2)
(ii)	State both parents’ genotypes and the gametes that are produced by each during the process of meiosis.
Male genotype:....................................................................Female genotype...........................................................
Male gametes:.....................................................Female gametes:	..............................................................
(2)
(iii)	Predict the genotypic and phenotypic ratios of the F2 generation. Show your working.
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 (2)
10.	(a)	State the two classes of compounds that compose chromosomes in animal cells.
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(b)	Outline how meiotic division results in almost an infinite genetic variation in the gametes produced.
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(c)	In a species of plant, tall is dominant to short and the production of round seeds is dominant to that of wrinkled seeds. The alleles are unlinked.
	A plant heterozygous for both characteristics is crossed with a plant homozygous for tall with wrinkled seeds.
Use the letters:
T - allele for tall
t - allele for short
R - allele for round seed
r - allele for wrinkled seed.
Determine the phenotypes and genotypes of the offspring of this cross.
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(2)
(d)	State how chromosome number can increase in human beings.
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IB HL Biology I –  Genetics Practice #5       Name: ______________________________ Block: ____
1.	The following is a DNA gel. The results are from a single probe showing a DNA profile for a man, a woman and their four children.

						[Source: The Biology Project, University of Arizona]
	Which fragment of DNA is the smallest?
A.	I
B.	II
C.	III
D.	IV
2.	The following is a DNA gel. The results are from a single probe showing a DNA profile for a man, a woman and their four children.

	Which child is least likely to be the biological offspring of the father?
A.	Child 1
B.	Child 2
C.	Child 3
D.	Child 4
3.	Outline a method for carrying out gene therapy, using a named example.
(Total 6 marks)
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4.	Discuss the ethical arguments for and against the cloning of humans.
(Total 4 marks)
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5.	Discuss the ethical issues for and against the use of transgenic plants.
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 (Total 6 marks)
6.	Outline the process of DNA profiling (genetic fingerprinting), including ways in which it can be used.
(Total 6 marks)
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8.	(a)	Define the term degenerate as it relates to the genetic code.
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(b)	Apart from international cooperation, outline two positive outcomes of the Human Genome Project.
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 (2)
(c)	State the catalytic activity of reverse transcriptase.
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(1)
(d)	State one use of monoclonal antibodies in diagnosis and one use in treatment.
Diagnosis:	..............................................................................................................
Treatment:	..............................................................................................................
(2)
9.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Define the term gene linkage and outline an example of a cross between two linked genes.
(8)
(b)	Describe the inheritance of ABO blood groups including an example of the possible outcomes of a homozygous blood group A mother having a child with a blood group O father.
(5)
(c)	Outline sex linkage.
(5)
10.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Outline how the process of meiosis can lead to Down’s Syndrome.
(4)
(b)	Discuss the advantages and disadvantages of genetic screening for chromosomal and genetic disorders.
(8)
(c)	Describe the technique for the transfer of the insulin gene using E. coli.
(6)
11.	The diagram below shows a DNA profiling of a family with five children. Segments of the DNA inherited by some members of the family are shown as two dark bands in each column. The DNA fragments are labelled A to F.

(a)	State two properties of the fragmented pieces of DNA which allow them to be separated in gel electrophoresis.
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 (1)
(b)	Determine which DNA fragment Son 2 inherited from his mother and which from his father.
From his mother: ........................................................................................................
From his father: ..........................................................................................................
(1)
(c)	Identify the child that genetically most resembles one of the grandparents.
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(1)
(d)	Apart from determining family relationships, outline one other application for DNA profiling.
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 (1)
12.	(a)	State two procedures used for the preparation of a DNA profile.
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(1)
	The following part of a DNA profile was used as evidence in a criminal investigation. DNA profiles of two suspects labelled S1 and S2 were compared to the DNA profile taken from the scene of the crime labeled E.

(b)	Analyse the profiles to determine which suspect was present at the crime scene.
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(2)