1. The thresholds for permanent sterility in men for an acute exposure and under prolonged exposure conditions are:

a. 0.5 to 1 Gy and 0.2 Gy/y, respectively.

b. 2.5 to 3 Gy and 1.5 Gy/y, respectively.

c. 3.5 to 6 Gy and 2 Gy/y, respectively.

d. 7.5 to 10 Gy and 6 Gy/y, respectively.

2. The thresholds for permanent sterility in women for an acute exposure and under prolonged exposure conditions are:

a. 0.5 to 1 Gy and 0.2 Gy/y, respectively.

b. 2.5 to 6 Gy and 0.2 Gy/y, respectively.

c. 3.5 to 6 Gy and 2 Gy/y, respectively.

d. 0.5 to 2 Gy and 2 Gy/y, respectively.

3. Which of the following statements is false?

a. The genetic information is coded in terms of the order of the bases (A, C, G, T) in the DNA molecule. The DNA is the essential ingredient of the chromosomes. The chromosomes thus carry the information that specifies all the characteristics of a human.

b. A gene is a finite segment of DNA. The gene is defined by the sequence of the bases it contains.

c. The position of a gene in the DNA molecule is called the "locus" of the gene.

d. Males have 22 pairs of autosomes plus a pair of X chromosomes. Females have 22 pairs of autosomes plus a Y and an X chromosome. One chromosome of each pair is derived from each parent.

4. A segment of a gene that is transcribed and translated into protein is called:

a. an intron.

b. an exon.

5. By the term "genome" we denote:

a. the DNA of the chromosomes.

b. the translated parts of the genes.

c. the DNA of the mitochondria.

d. the DNA of the chromosomes and mitochondria.

6. Which of the following statements is false:

a. By "mutations of the genome" we mean changes in bases of the DNA of the chromosomes.

b. Mutations can occur both in somatic cells and in germs cells.

c. Mutations in the germ cells are more apparent than mutations in the somatic cells, unless the latter ones occur under conditions of clonal proliferation (cancer).

d. Mutations in the germ cells can cause death during embryonic development or adverse effects in the progeny ("genetic diseases" or "hereditary diseases").

7. Which of the following statements is false:

a. If the two chromosomes in a chromosome pair have the genes for given characteristics lined up in the same order, the two chromosomes are called "homologous".

b. If the two chromosomes in a chromosome pair have the genes for given characteristics lined up in different orders, the two chromosomes are called "heterologous".

c. In a given chromosome pair, if the two genes controlling the same characteristic are alike, the person is said to be homozygous for that pair of genes.

d. In a given chromosome pair, if the two genes controlling the same characteristic are different, the person is said to be heterozygous for that pair of genes.

e. The chromosomes in the XY pair are homologous.

8. A recessive gene does not express itself if:

a. the person is homozygous for the recessive gene.

b. the person is heterozygous for the recessive gene.

c. the recessive gene is on a pair of heterologous chromosomes.

d. the corresponding gene on the other chromosome is not completely dominant.

9. Genetic diseases are divided into: mendelian, chromosomal and multifactorial.

a. True.

b. False.

10. Which of the following statements referring to mendelian diseases is false?

a. Mendelian diseases are caused by a mutation on a single gene either on the autosomes or on the sex chromosomes.

b. Mendelian diseases are subdivided into: autosomal dominant, autosomal recessive and X-linked.

c. Autosomal dominant diseases are caused by dominant mutant genes and autosomal recessive diseases are caused by recessive mutant genes.

d. Autosomal recessive diseases are always expressed in the first generation of the progeny.

11. X-linked recessive mendelian diseases are caused by recessive genes located on:

a. an autosome.

b. the Y chromosome.

c. the X chromosome.

12. Which of the following statements is false?

a. Chromosomal diseases are caused by gross abnormalities in the structure of the chromosomes or in the total number of chromosomes.

b. Multifactorial diseases have a genetic component and an environmental component and their expression varies among individuals, families and populations.

c. Most of the genetic diseases observed in a population are mendelian or chromosomal.

13. The effect of radiation on genetic diseases is:

a. to introduce new types of diseases.

b. to increase the occurence probability of naturally existing diseases.

c. both of the above.

14. The doubling dose is used to estimate the hereditary risks of radiation. It is the dose required to produce as many mutations as those naturally occuring in a generation. The doubling dose is used in the estimation of:

a. the absolute mutation risk.

b. the relative mutation risk.

15. The estimation of the hereditary risks of radiation is mainly based on:

a. studies of the children of the survivors at Hiroshima and Nagasaki.

b. animal data.

16. In the megamouse project, both male and female mice were irradiated with different doses, dose-rates and fractionation patterns to estimate:

a. the relative mutation risk for seven specific-locus mutations.

b. the absolute mutation risk for seven specific-locus mutations.

17. Based on mice data, the doubling dose for humans (at low dose-rate exposures) has been calculated to be:

a. 0.2 Gy.

b. 1 Gy.

c. 2.5 Gy.

d. 5 Gy.