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WorksheetsIB Biology Topics 3.1 and 3.2 (Genetics)
Total questions: 32
Worksheet time: 10mins
The image shows a karyogram. What information can be determined from this karyogram?
The sex is female.
The haploid number is 54.
Disjunction occurred during meiosis.
The species is not human.
Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is based on DNA sequences and the cladogram on the right is based on comparing protein sequences.
What is the reason that cladograms based on DNA sequences are more reliable predictors of the phylogenetic relationship of species than cladograms based on protein sequences?
Amino acids are not as chemically stable as DNA nucleotides.
DNA mutates but amino acids do not.
Several different triplets of bases can code for the same amino acid.
There are 20 different amino acids but only 4 nucleotides.
What distinguishes an allele from a gene?
An allele is made of RNA.
An allele is shorter.
An allele is a variety of a gene.
An allele cannot be transferred during genetic modification.
Which is a characteristic of the pairs of sister chromatids that are visible during meiosis?
They result from the replication of DNA before meiosis.
They are only present in meiosis I.
They split apart during metaphase I in meiosis.
They are only present in meiosis II.
The bacterium Neisseria gonorrhaeae causes infections related to the human reproductive system. The graph shows the percentage of samples in which this bacterium showed resistance to six antibiotics over a period of ten years.
What is a possible explanation for the total percentage resistance being larger than 100% in 2010?
People do not take the antibiotics as prescribed.
More people have been sampled in that year.
There was an epidemic of Neisseria gonorrhaeae in that year.
Some bacteria are resistant to more than one antibiotic.
Which is a characteristic of the haploid number of eukaryotic chromosomes?
It doubles in mitosis.
It is fixed for each species.
It is an even number for all species.
It is positively correlated with an animal's mass.
The diploid number of chromosomes in humans (Homo sapiens) is 46 and the diploid number of chromosomes in rice (Oryza sativa) is 24. What does this indicate about diploid chromosome numbers?
Plant species have a lower diploid number of chromosomes in animals.
Members of a species have the same diploid number of chromosomes.
The evolutionary progress of species is determined by the diploid number of chromosomes.
The complexity of the organisms is correlated to the diploid number of chromosomes.
What is characteristic of homologous chromosomes?
They have an identical DNA sequence.
They are of the same length in karyograms.
They form pairs in prokaryotes.
They carry the same alleles.
What is the effect of dominant alleles?
I. They mask the effect of recessive alleles.
II. They become more frequent than recessive alleles in a population.
III. They have a joint effect with recessive alleles when characteristics are co-dominant.
I only
I and II only
I and III only
I, II and III
What is a possible source of the chromosomes used for pre-natal karyotype diagnosis?
The mother's lymphocytes.
The mother's cheek cells.
The cells from the chorionic villi.
The fetal hair root cells.
What causes the presence of three chromosomes 21 in Down syndrome?
Crossing over
Allele change
Non-disjunction
Gene mutation
What is a characteristic of the human Y chromosome?
It is made of DNA and histones covered by phospholipids.
It contains some genes that are not present on the X chromosome.
It is the largest chromosome in the human karyotype.
It has a condensed length of approximately 100 µm.
What is the composition of eukaryotic chromosomes?
DNA only
DNA and ribose
DNA and RNA
DNA and proteins
The image shows a human karyotype.
According to the image, what conditions can be determined?
Non-disjunction has occurred and the individual is male.
Non-disjunction has occurred and the individual is female.
The individual is female and has Down syndrome.
The individual is male and has Down syndrome.
What information can be concluded from the karyotype?per
The person is a normal male.
The person is a normal female.
The person is a male with Down syndrome.
The person is a female with Down syndrome.
Which genetic condition can be diagnosed by karyotyping?
Trisomy 21
Sickle-cell anemia
Hemophilia
Colour blindness
What is the name given to a heritable factor which controls a specific characteristic?
Allele
Chromosome
Gene
Mutation
What commonly causes Down syndrome in humans?
Non-disjunction
Base substitution
Amniocentesis
Gene mutation
The sequence of the first six amino acids of the normal β hemoglobin (HbA) chain are listed.
valine – histidine – leucine – threonine – proline – glutamic acid
Which sequence of amino acids could there be in the first six amino acids of the sickle-cell β hemoglobin (HbS) chain?
glutamic acid – histidine – leucine – threonine – proline – valine
valine – valine – histidine – leucine – threonine – proline
glutamic acid – histidine – leucine – threonine – proline – glutamic acid
valine – histidine – leucine – threonine – proline – valine
What is a gene mutation?
Failure of chromosome pairs to separate properly during cell division
Changes to genes caused by natural selection
Changes to the nucleotide sequence of the genetic material
Changes in karyotypes
Which is a source of chromosomes for pre-natal diagnosis of abnormalities by karyotyping?
Sperm
Ovaries
Erythrocytes
Chorionic villi
Which statement is a definition of a gene?
The whole of the genetic information of an organism
The factor that affects the phenotype in the homozygous state
A heritable factor that controls a specific characteristic
The factor that affects the phenotype in the heterozygous state
A human cell has between 20 000 and 25 000 genes whereas an E. coli cell has approximately 4000 genes. Which of the following statements is true?
The human genome is larger than the E. coli genome.
There are more genes on each human chromosome than on the E. coli chromosome.
The human cell and the E. coli cell produce approximately the same variety of proteins.
The DNA in both organisms is associated with histones (proteins).
What is the difference between the alleles of a gene?
Their position on the chromosome
Their amino acid sequence
Their pentose sugars
Their base sequence
Which of the following statements about homologous chromosomes is correct?
Each gene is at the same locus on both chromosomes.
They are two identical copies of a parent chromosome which are attached to one another at the centromere.
They always produce identical phenotypes.
They are chromosomes that have identical genes and alleles.
In some people, hemoglobin always contains the amino acid valine in place of a glutamic acid at one position in the protein. What is the cause of this?
An error in transcription of the hemoglobin gene
An error in translation of the mRNA
Lack of glutamic acid in the diet
A base substitution in the hemoglobin gene
What are homologous chromosomes?
Identical chromosomes
Non-identical chromosomes with different genes
Non-identical chromosomes with the same genes in the same sequence but not necessarily the same alleles
Non-identical chromosomes with the same genes in a different sequence and not necessarily the same alleles
Which of the following is the cause of sickle-cell anemia?
Tryptophan is replaced by leucine.
Leucine is replaced by valine.
Glutamic acid is replaced by valine.
Lysine is replaced by glutamic acid.
What does the karyogram below correspond to?
A normal male
A normal female
A female with Down syndrome
A male with Down syndrome
The Human Genome Project allowed the first accurate estimates of the number of different genes in the human genome. What was a typical estimate, based on the results of the Human Genome Project?
46
64
25 000
1 000 000
What is the set of alleles that an individual possesses?
A gene
A genotype
A genome
A genus
Which of the following is an inherited disease that is due to a base substitution mutation in a gene?
Trisomy 21
AIDS
Type II diabetes
Sickle cell anemia
