Medical genetics /The human genome/ /Nucleic acid structure and function

Self-assessment:Questions

Medical genetics /The human genome/ /Nucleic acid structure and function

1. Which of the following is not a typical feature of mitochondrial inheritance?

A. Maternal transmission

B. Heteroplasmy

C. More introns in mitochondrial genes than in nuclear genes

D. Th e presence of fewer than 40 genes in the mitochondrial genome

E. Lack of a straightforward genotype – phenotype Relationship

2. In preimplantation genetic diagnosis (PGD), which of the following does not take place?

A. In vitro fertilisation

B. Testing of each of the cells of the embryo for the specific mutation

C. Fetal sex determination of embryos in sex - linked disease

D. Th e use of the polymerase chain reaction (PCR) to detect a specific mutation or haplotype

E. Th e use of fluorescence in situ hybridisation (FISH) to detect an unbalanced chromosome abnormality

3. Which one of the following conditions is not usually regarded as multifactorial?

A. Rheumatoid arthritis

B. Insulin - dependent diabetes mellitus

C. McCune – Albright syndrome

D. Asthma

E. Parkinson disease

4. Which of the following is not useful in connection with the following genetic conditions?

A. Venesection for iron overload in haemochromatosis

B. Regular blood pressure check in neurofi bromatosis type 1 (NF1)

C. Neonatal screening for hypothyroidism and phenylketonuria (PKU)

D. Dietary treatment for PKU

E. Enzyme replacement therapy for familial adenomatous polyposis (FAP

5. Which of the following pairings between individuals and a genetics landmark is incorrect?

A. Mendel and the independent assortment of different gene pairs to gametes

B. Flemming and the identification of chromosomes within the nucleus

C. Th e discovery of the helical structure of DNA and Watson, Crick, Franklin and Wilkins

D. The first identification of a chromosomal abnormality and Jeffreys

E. PCR and Mullis

6. Which of the following statements are true?

A. Th e human genome contains approximately 3 million base pairs

B. PaleGiemsa staining chromosomal regions tend to have a higher G + C content and to be relatively gene - rich

C. Around 50% of the human genome codes for proteins

D. Some RNA molecules are transcribed from DNA and can regulate the expression of other genes

E. Th e genome was sequenced using a radioactively labelled DNA sequencing method

F. Th e number of genes perautosome increases wit chromosome number from chromosome 1 to 22, with chromosome 1 containing the fewest

7. Which one of the following is not true of human RNA molecules?

A. They may undergo splicing

B. They can function in the splicing process

C. They are present in the nucleus but not in the cytoplasm

D. They can form functional complexes with proteins

E. They are generally single – stranded

8. Which of the following four statements are true?

1. Th e pyrimidine bases are cytosine and guanine

2. Base pairing is by hydrogen bonds

3. C pairs with T and A pairs with G

4. Th e sugar – phosphate backbone of the DNA molecule relies on covalent rather than hydrogen bonds

9. Which of the following does not play a role in the regulation of transcription?

A. Transcription factors

B. Enhancer sequences

C. Silencer sequences

D. The promoter

E. The spliceosome

10. Which of the following genetic alterations or repair defects is correctly paired with the associated disease?

A. Base excision repair defect and xeroderma pigmentosum

B. Nucleotide excision repair defect and MutYH – associated polyposis

C. Mismatch repair defect and Huntington disease

D. Trinucleotide repeat length mutation and colon cancer

E. Chromosomal microdeletion deletion and Williams Syndrome

11. Which of the following would be least likely to result in a reduced amount or shortening of a protein encoded by a 20 - exon gene?

A. A 2 bp insertion in the second exon

B. A 1 bp deletion in the third exon

C. A nonsense mutation in the sixth exon

D. A T to C nucleotide substitution in the middle of the fifth exon

E. Methylation of the cytosines surrounding the promoter

12. Which of the following is not a post – translational modification?

A. Phosphorylation

B. Polyadenylation

C. Glycosylation

D. Proline hydroxylation

E. Disulphide bond formation