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WorksheetsIB Biology SL Topic 3 Pretest
Total questions: 25
Worksheet time: 17mins
I. Size of the chromosomes
II. Gene mutations of the chromosomes
III. Age of the individual
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.
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.
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
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).
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.
a) co-dominance
b) multiple alleles
c) sex-lingage
d) polygenic traits
