IB Biology Topic 3.1 MCQ's

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? A. The human genome is larger than the E. coli genome. B. There are more genes on each human chromosome than on the E. coli chromosome. C. The human cell and the E. coli cell produce approximately the same variety of proteins. D. The DNA in both organisms is associated with histones (proteins).

A

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. A. I only B. I and II only C. I and III only D. I, II and III

A

What is the set of alleles that an individual possesses? A. A gene B. A genotype C. A genome D. A genus

B

Which of the following is an inherited disease that is due to a base substitution mutation in a gene? A. Trisomy 21 B. Sickle cell anemia C. AIDS D. Type II diabetes

B

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? A. 46 B. 64 C. 25 000 D. 1 000 000

C

What distinguishes an allele from a gene? A. An allele is made of RNA. B. An allele is shorter. C. An allele is a variety of a gene. D. An allele cannot be transferred during genetic modification.

C

What is a gene mutation? A. Failure of chromosome pairs to separate properly during cell division B. Changes to genes caused by natural selection C. Changes to the nucleotide sequence of the genetic material D. Changes in karyotypes

C

What is the name given to a heritable factor which controls a specific characteristic? A. Allele B. Chromosome C. Gene D. Mutation

C

Which of the following is the cause of sickle-cell anemia? A. Tryptophan is replaced by leucine. B. Leucine is replaced by valine. C. Glutamic acid is replaced by valine. D. Lysine is replaced by glutamic acid.

C

Which statement is a definition of a gene? A. The whole of the genetic information of an organism B. The factor that affects the phenotype in the homozygous state C. A heritable factor that controls a specific characteristic D. The factor that affects the phenotype in the heterozygous state

C

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? A. An error in transcription of the hemoglobin gene B. An error in translation of the mRNA C. Lack of glutamic acid in the diet D. A base substitution in the hemoglobin gene

D

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? A. glutamic acid - histidine - leucine - threonine - proline - valine B. valine - valine - histidine - leucine - threonine - proline C. glutamic acid - histidine - leucine - threonine - proline - glutamic acid D. valine - histidine - leucine - threonine - proline - valine

D

What is the difference between the alleles of a gene? A. Their position on the chromosome B. Their amino acid sequence C. Their pentose sugars D. Their base sequence

D