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Mixed Test (Biology)

Description: This test will help the students to revise the topics thoroughly.
Number of Questions: 15
Created by:
Tags: Human diseses Immunology and Vaccination Vaccination and Immunisation Pregnancy and Parturition Pregnancy and Development
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Baculovirus vectors can be produced in cell lines derived from ________.

  1. moth

  2. chicken bursa

  3. chinese hamster ovary

  4. tobacco

  5. green monkey kidney


Correct Option: A
Explanation:

Baculovirus vectors in moth cell lines produce large amounts of glycosylated recombinant protein. The baculovirus is a natural infectious agent of insect cells.

Herd immunity has been deemed instrumental in rapid disease eradication. What is the minimum percentage of children which needs to be vaccinated successfully, in order to achieve herd immunity to diphtheria?

  1. 100%

  2. 10%

  3. 50%

  4. 75%

  5. Herd immunity cannot be achieved against diphtheria


Correct Option: D
Explanation:

Herd immunity can only be achieved in those diseases which depend on human transmission, such as diphtheria. Thus, in the case of tetanus, active immunization is of benefit to the individual, but not to the community, since it will not eliminate the organism which is found in the feces of domestic animals and persists in soil as highly resistant spores.

Which one of the following diseases has been completely eradicated world-wide?

  1. Measles

  2. Smallpox

  3. Tuberculosis

  4. Cowpox

  5. Psittacosis


Correct Option: B
Explanation:

The eradication of smallpox was due to an enormous World Health Organization (WHO)-sponsored effort combining extensive vaccination and selective epidemiologic control methods. The WHO also hopes to eradicate poliomyelitis in the near future.

Which of the following is the most important risk factor in the aetiology of intraventricular haemorrhage (IVH)?

  1. Coagulation disorder

  2. Intermittent positive-pressure ventilation

  3. Pneumothorax

  4. Extreme prematurity

  5. Hypoxic–ischaemic encephalopathy


Correct Option: D
Explanation:

Prematurity is the most important risk factor, with IVH being very rare in term infants.

A subunit vaccine makes use of just a small portion of a pathogen. A small protein subunit used in a vaccine may fail to stimulate T-cell immunity because of the

  1. lack of glycosylation

  2. lack of conformation

  3. lack of carrier determinants

  4. HLA-related unresponsiveness

  5. inherently insufficient antigen concentration


Correct Option: D
Explanation:

A major concern about subunit vaccines, especially when just short peptides are used, is the variation in ability to associate with the different polymorphic forms of MHC molecules present in an outbred population.

Which of the following is the most useful tool in the prediction of neurodevelopmental outcome for a baby with moderate encephalopathy secondary to hypoxic–ischaemic encephalopathy (HIE)?

  1. Doppler assessment of the cerebral arteries

  2. Bedside amplitude integrated EEG

  3. MRI

  4. Neurological examination

  5. Cranial ultrasound


Correct Option: C
Explanation:

The change that best predicts a bad outcome is abnormality in signal intensity in the posterior limb of the internal capsule (PLIC) and basal ganglia with 90% sensitivity and 100% specificity, and positive predictive value of 100%.

After examining a newborn female infant, doctor found that she was suffering form sensorineural deafness. Which one of the following is the most common cause of sensorineural deafness in newborn infants?

  1. Prematurity

  2. Autosomal dominant inheritance

  3. Autosomal recessive inheritance

  4. Congenital rubella

  5. Hyperbilirubinaemia


Correct Option: C
Explanation:

Inherited causes now account for 50% of all cases of severe sensorineural hearing impairment; 80% are due to single-gene autosomal recessive disorders and 15% to autosomal dominant disorders.

Which one of the following is most likely to lead to a decrease in the need for early top-up blood transfusion for extremely preterm infants?

  1. Iron supplementation

  2. Erythropoietin

  3. Vitamin E supplementation

  4. Decreased frequency of blood sampling

  5. Folate supplementation


Correct Option: A
Explanation:

In preterm infants, Iron stores are low and exhausted quickly because of the infant's rapid growth rate. However routine administration of iron is controversial and not given in all units

Which one of the following conditions does not causes hydrops fetalis in an infant?

  1. α-Thalassemia

  2. β-Thalassemia

  3. ABO incompatibility

  4. Rhesus isoimmunisation

  5. Twin-to-twin transfusion


Correct Option: B
Explanation:

Classic β-thalassaemia major does not affect neonates because most of the haemoglobin is in the fetal (HbF) form.

A potential disadvantage of immunological protection using passive transfer of horse globulins is

  1. irreversible protection

  2. lack of antibody-mediated immune response

  3. type IV hypersensitivity reactions

  4. immunodeficiency

  5. serum sickness


Correct Option: E
Explanation:

Horse globulins containing anti-tetanus and anti-diphtheria toxins have been extensively employed prophylactically, but have the drawback that serum sickness develops in response to foreign proteins, producing vasculitic skin rashes, swollen joints and transient albuminuria due to immune complex-mediated inflammatory reactions.

Protein based subunit vaccines present an antigen to the immune system without viral particles. An antibody response to a protein vaccine can only be obtained

  1. if the molecule is first linked to a carrier

  2. if the molecule maintains discontinuous epitopes

  3. if the peptide bonds are maintained

  4. if the molecule is glycosylated

  5. if disulfide bonds are maintained


Correct Option: C
Explanation:

The peptide bonds hold the amino acids together and if these are not maintained, then the vaccine will simply consist of a mixture of amino acids; not much use as a specific vaccine.

A live attenuated viral vaccine can be given to _________.

  1. patients treated with steroids

  2. pregnant women

  3. patients with leukemia

  4. patients treated with radiotherapy

  5. children under 8 years of age


Correct Option: E
Explanation:

Live attenuated organisms can be safely administered to children under 8 years of age, so long as they are not immunodeficient. Attenuated vaccines for poliomyelitis (Sabin), measles and rubella have gained general acceptance and are routinely given to babies and infants.

Which among the following statements does not characterises an idiotype?

  1. It is independent of the constant region of the T-cell receptor.

  2. An epitope is an antigenic determinant.

  3. Idiotype is sometimes used to describe the collection of multiple idiotopes.

  4. The idiotype describes the distinctive sequence and region that makes any immunoglobing.

  5. The idiotype defines the surface and properties of the constant region of antigen receptors of T cells.


Correct Option: E
Explanation:

Idiotype defines the surface and properties of the variable region and of antigen receptors of T cells. Thus, determining the antigen specificity and therefore the idiotope of the molecule.

Tetanus toxoid is usually given to humans

  1. together with the toxin

  2. without the addition of any other agent

  3. with complete Freund's adjuvant

  4. absorbed to aluminum hydroxide

  5. only as a therapeutic agent, not prophylactically


Correct Option: D
Explanation:

Bacterial exotoxins can be detoxified by formaldehyde treatment which does not destroy the major immunogenic determinants. The toxoid is generally given after adsorption to aluminum hydroxide which acts as an adjuvant and produces higher antibody titers.

A feature of a Salmonella-based vaccine expressing antigens from other infectious agents is that

  1. immunity is limited to the gut

  2. only secretory IgA is elicited

  3. it does not invade the mucosal lining of the gut

  4. it provokes both oral and systemic immunity

  5. the organism does not need to be attenuated


Correct Option: D
Explanation:

Salmonella infects cells of the mononuclear phagocyte system throughout the body and thereby stimulates the production of cell-mediated immunity, in addition to both secretory and systemic antibody production. It can be made to express proteins from shigella, cholera, malarial sporozoites, etc and has potential as an orally administered vaccine.

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