Biology Multiple Choice Questions
- In situ hybridisation:
- a. to detect rnRNA for protein products
- b. detect location of mRNA in cell ✅
- c. method is as sensitive as immunofluorescence methods
- Concerning mitochondrial DNA:
- a. deletions have been demonstrated in human diseases
- b. codes for parts of mitochondrial enzymes
- c. originates in cell nucleus
- d. exhibits RFLP
- e. familial pathogenic mutations are always of maternal origin ✅
- With respect to mRNA, it can be determined by:
- a. Southern blot
- b. in-situ hybridisation with labelled oligonucleotides
- c. Northern blot ✅
- d. PCR
- e. in-situ hybridisation with labelled DNA probes
- Which of the following is/are true of genes?
- a) Mitochondrial genes are all maternally derived
- b) Splicing of introns occurs in mRNA ✅
- c) Less than 10% of DNA is translated
- d) Oncogenes are normal components of human DNA
- e) Oncogenes are activated by the process of chromosomal translocation
- Which of the following is/are true of genetic linkage?
- a) A low lod score indicates linkage of two genes
- b) It is distinct from association
- c) Autosomal crossovers are equally frequent in males and females ✅
- d) Linked gene loci are sometimes on different chromosomes
- e) Linkage disequilibrium is used in DNA diagnosis
- Which of the following diseases can be diagnosed prenatally by DNA diagnostic tests?
- a) Duchenne muscular dystrophy
- b) Cystic fibrosis
- c) Sturge-Weber syndrome
- d) Haemophilia A
- e) Polycystic kidney disease ✅
- Which of the following is/are true of autosomal recessive disorders?
- All offspring of two individuals with autosomal recessive disorder will be affected
- Genetic counselling for members of affected families is based on the assumption that mutation rates are high ✅
- Both parents heterozygotes for Cystic Fibrosis gene. They have 4 children. Which of the following are true:
- a) The chance that no children will be affected is the same as that all children will be affected
- b) The probability that no children will be affected is < 5%
- c) The most likely outcome is one affected child
- d) The chance of 4 affected children ✅
- _____ An allele is ___.
- A. one of the bases in DNA
- B. an alternate form of a gene ✅
- C. another term for epistasis
- D. present only in males and is responsible for sex determination
- E. found in mitochondria but not in nuclei
- _____ What is the probability that on four flips of a coin, heads will occur on three flips and tails on 1?
- A. 1/4
- B. 1/2
- C. 3/16 ✅
- D. 1/8
- E. insufficient information to answer this
- _____ What would be the dimensions of a Punnett square for the cross Ww x ww?
- A. 4 x 4
- B. 2 x 2 ✅
- C. 2 x 1
- D. 1 x 1
- _____ In dihybrid crosses, the ratio 9:3:3:1 indicates ___.
- A. Codominance
- B. Independent assortment ✅
- C. Intermediate dominance
- D. Three alleles for each trait
- _____ In a cross of a round hybrid pea with a true breeding round parent (Ww x WW), what genotypic proportions would be observed in the offspring?
- A. Half heterozygous, half homozygous dominant
- B. Half round, half wrinkled
- C. All heterozygous
- D. All round ✅
- _____ The fundamental Mendelian process which involves the separation of contrasting genetic elements at the same locus would be called ___.
- A. segregation ✅
- B. independent assortment
- C. continuous variation
- D. discontinuous variation
- E. dominance or recessiveness
- _____ Probabilities are calculated using the addition rule when they ___.
- A. Are equally likely
- B. Are independent
- C. Are mutually exclusive ✅
- D. Occur disproportionately
- _____ Probabilities are calculated using the multiplication rule when they ___.
- A. Are equally likely
- B. Are independent ✅
- C. Are mutually exclusive
- D. Occur disproportionately
- _____ What ratios typically result from crosses dealing with a single genetic locus?
- A. 9:3:3:1, 1:2:1
- B. 1:1:1:1, 1:4:6:4:1
- C. 3:1, 1:1, 1:2:1 ✅
- D. 9:7, 12:3:1
- E. 15:1, 1:2
- _____ There are three different genotypes resulting from a monohybrid cross. How many different genotypes would there be resulting from a dihybrid cross?
- A. 4
- B. 8
- C. 9 ✅
- D. 16
- _____ The base thymine is always paired with ___.
- A. Adenine ✅
- B. Guanine
- C. Cytosine
- D. Thymine
- _____ The sequence of one strand of DNA is 5’ TCGATC 3’. The sequence of the complementary strand would be ___.
- A. 5’ AGCTAG 3’
- B. 5’ TCGATC 3’
- C. 5’ CTAGCT 3’ ✅
- D. 5’ GCTAGC 3’
- E. 5’ GATCGA 3’
- _____ Starting with a cross between AA and aa, the proportion of heterozygotes in the F2 progeny will be ___.
- A. 1/8
- B. 1/4
- C. 1/3
- D. 1/2 ✅
- E. All heterozygotes
- _____ Genotype is to DNA as phenotype is to ___.
- A. Genotype
- B. Proteins ✅
- C. Expressivity
- D. RNA
- E. Mutation
- _____ Albinism, lack of pigmentation in humans, results from an autosomal recessive gene designated a. Two parents with normal pigmentation have an albino child. What is the probability that their next child will be albino? What is the probability that the next child will be an albino girl?
- A. 1/2; 1/4
- B. 1/4; 1/2 ✅
- C. 1/4; 1/8
- D. 1/8; 1/4
- _____ Starting with a P generation with the following genotypes (AABB x aabb). Based on classical Mendelian inheritance, what is the expected phenotypic ratio observed among the F2 progeny?
- A. 9:3:3:1 ✅
- B. 1:2:1
- C. 3:1
- D. 1:1
- E. 1:1:1:1
- _____ In the previous, if A = plain fur and a = spotted fur and B = Long ears and b = short ears, what phenotypic class would be observed in the highest proportion in the F2 generation?
- A. spotted – short ears
- B. plain – short ears
- C. spotted – long ears
- D. plain – long ears ✅
