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Biology

Description: This test is based on certain topics from biology which are highly beneficial for learning aspirants.
Number of Questions: 15
Created by:
Tags: cardiovascular system mascular system respiratory system etc. Human Heart Anatomy of Human Heart Blood Coagulation Blood Coagulation Mechanism Heart Beat and its Control Nervous Control of Heart Double Circulation Human Circulatory System
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Which among the following statements regarding haemostasis is not true?

  1. Platelet activation stimulates production of thromboxane A2 (TXA2) by cyclooxygenase (COX).

  2. Aggregation of platelets is stimulated by ADP via P2Y receptors.

  3. Primary haemostasis initially involves vasodailation.

  4. Fibrin is broken down by plasmin.

  5. Binding of thrombin to thrombomodulin prevents cleavage of fibrinogen.


Correct Option: C
Explanation:

Primary haemostasis initially involves vasoconstriction in response to vascular damage which limits blood loss, and platelet adhesion and activation due to exposure and binding to subendothelial matrix.

In the process of blood clotting the antithrombin is activated by

  1. aspirin

  2. warfarin

  3. heparin

  4. P2Y receptor

  5. GPIIb/IIIa receptor antagonists


Correct Option: C
Explanation:

Heparin is a highly effective anticoagulant. Unfractionated heparin activates antithrombin which inactivates thrombin and factors IXa and Xa.

Which of the following does not characterise the cardiovascular system of the body?

  1. The cardiovascular system distributes electrolytes to the body cells and nullifies thermoregulation.

  2. Blood re-enters the heart through the vena cave

  3. Perfusion of the systemic circulation requires a much higher pressure.

  4. The systemic and pulmonary circulations are perfused in series.

  5. The elastic arteries are the aorta and its major branches.


Correct Option: A
Explanation:

The key functions of the cardiovascular system are distribution of O2, water, electrolytes and nutrients to all body tissues, transportation of CO2 and metabolic waste products from the tissues to the lungs and kidneys and thermo regulation.

In a normal healthy person a tonic depression of heart rate and vascular tone is caused by

  1. chemoreceptor reflexes

  2. cardiopulmonary reflexes

  3. stretch receptors reflexes

  4. baroreceptor reflex

  5. cardiovascular receptors reflex


Correct Option: B
Explanation:

Cardiopulmonary reflexes are diverse cardiovascular reflexes originating in the heart and lungs that exert a tonic depression of heart rate and vascular tone.

The ventricular origin of the heart beat is represented by

  1. the QT interval

  2. the PR interval

  3. the QRS

  4. the ST segment

  5. the T wave inversion


Correct Option: C
Explanation:

The QRS complex is one of the components of a typical electrocardiogram (ECG) tracing of a complete cardiac cycle, normally occuring after the P wave. A wide and misshapen QRS may reflect bundle branch block or ventricular origin of the heart beat.

The spread of oncogenic cells in the body is known as

  1. new synthesis

  2. metastasis

  3. angiogenesis

  4. apoptosis

  5. biosynthesis


Correct Option: B
Explanation:

Metastasis is the process by which cancer cells spread from the original tumour and set up secondary tumours in other parts of the body.

Boon and colleagues showed that syngeneic transplantable tumors which mutate such that they express strong transplantation antigens are rejected. They called these variants

  1. tum

  2. Xenogeneic

  3. Tum +

  4. MCA

  5. non-immunogenic


Correct Option: A
Explanation:

Tum cell lines are those which have mutated such that they cannot be grown in syngeneic animals with a normal immune system.

_____________ is related directly with an abnormality of the humoral immune response?

  1. Bruton's agammaglobulinemia

  2. Chronic mucocutaneous candidiasis

  3. Ataxia telangiectasia

  4. Wiskott Aldrich syndrome

  5. DiGeorge syndrome


Correct Option: A
Explanation:

In the above question the only immune deficiency disorder that is related with an abnormality exclusively of the humoral response is Bruton's agammaglobulinemia.

Anuj is suffering from pancreatic carcinoma. In pancreatic carcinoma the ras gene

  1. is absent

  2. contains a single point mutation, but not always at the same position

  3. is normal but is over expressed

  4. has a large deletion

  5. has large insertions


Correct Option: B
Explanation:

A point mutation leads to a single amino acid substitution at either position 12, 13 or 61. These mutations are found in over 90% of patients with pancreatic carcinomas, in 40% of patients with colorectal cancers and their preneoplastic lesions, in acute myeloid leukemia (AML) and in preleukemic syndromes.

Agglutinin is an antibody which aggregates a particulate antigen on BBCs. Wheat germ agglutinin binds strongly to

  1. surface lipoproteins on resting T-cells

  2. surface glycoproteins on resting T-cells

  3. surface glycoproteins on resting B-cells

  4. surface glycoproteins on activated T- and B-cells

  5. surface lipoproteins on activated T- and B-cells


Correct Option: D
Explanation:

Within 24 h of stimulation by lymphocyte polyclonal activators, high concentrations of binding sites for this lectin appear on the surface of the cell.

Mrs. Bhatiya is12 weeks pregnant and is noted to have an elevated blood pressure and proteinuria on a routine pregnancy health check. Which of the following statements is true?

  1. Cardiac output falls during pregnancy.

  2. She has pre-eclampsia .

  3. An underlying glomerulonephritis could be present .

  4. Most pregnant patients have significant proteinuria .

  5. Blood pressure always rises during pregnancy .


Correct Option: C
Explanation:

If blood pressure is relatively high in early pregnancy, this is abnormal. There are a number of causes of this including an underlying glomerulonephritis or pre-existing essential hypertension.

The Rh (Rhesus) blood group is related to

  1. A Antigen

  2. B Antigen

  3. O Antigen

  4. AB Antigen

  5. D antigen


Correct Option: E
Explanation:

The Rh (Rhesus) blood group is related to D antigen on red cells, present in 85% of the population (Rh+).Antibody to D antigen can be raised in Rh individuals by transfusion of Rh+ blood or when red cells from a Rh+ fetus enter the circulation of a Rh mother. This can cause haemolytic disease of the newborn .

The accurate assessment of global and ventricular function, myocardial perfusion and myocardial scar is done through

  1. a thallium scan

  2. the right heart catheterization

  3. the echocardiogram

  4. the chest X-ray

  5. the cardiac magnetic resonance imaging


Correct Option: E
Explanation:

Cardiac magnetic resonance imaging is a non-invasive imaging modality providing accurate assessment of global and ventricular function, myocardial perfusion and myocardial scar.

The Na+ electrochemical gradient is reduced by:

  1. beta 1-adrenergic agonists

  2. phosphodiesterase inhibitors

  3. digoxin

  4. NCX

  5. SERCA


Correct Option: C
Explanation:

Partial inhibition of the Na+ pump with digoxin reduces the Na+ electrochemical gradient, thus impeding NCX, so more Ca2+ remains in the cell to support the next beat.

Which of the following is the main prefered target for cancer therapy?

  1. Integrins

  2. Angiostatin

  3. Interleukins

  4. Cyclins

  5. Fibrin


Correct Option: A
Explanation:

Integrins are a family of transmembrane glycoprotein receptors that mediate cell-matrix.They are involved in the anchoring of cells to an extracellular matrix. They affect tumour progression, and this has made them an appealing target for cancer therapy.

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