Category: Class 11 Biology Objective Questions

Biology Multiple Choice Questions on “Body Fluids and Circulation Basics”.

1. Which of the following is the most commonly used body fluid?
a) Blood
b) Plasma
c) Lymph
d) Serum
Answer: a
Clarification: Blood is the most commonly used body fluid by most of the higher organisms including humans for the transportation of essential nutrients to the body tissues. Another body fluid, lymph also helps in the transport of certain substances.

2. Which of the following is absent on blood?
a) Fluid matrix
b) Plasma
c) Fibroblast
d) Formed elements
Answer: c
Clarification: Fibroblast are special cells which are responsible for the formation of fibres in the areolar tissue which is a type of connective tissue. Blood is a special type of connective tissue which consists of a fluid matrix, plasma and formed elements.

3. How much percentage of plasma is present in the blood?
a) 35%
b) 45%
c) 50%
d) 55%
Answer: d
Clarification: Plasma constitutes nearly 55% of the blood. 90-92% of plasma is water and proteins contribute 6-8 per cent of it. Fibrinogens, albumins and globulins are the major proteins.

4. Which of the following are needed for clotting of blood?
a) Fibrinogen
b) Albumin
c) Globulin
d) Magnesium ions
Answer: a
Clarification: Fibrinogens are needed for clotting or coagulation of blood. Globulins primarily are involved in defence mechanisms of the body and the albumins help in the osmotic balance.

5. What is plasma without clotting factors known as?
a) Blood
b) Serum
c) Lymph
d) Fluid
Answer: b
Clarification: Plasma without the clotting factors is known as serum. Factors for coagulation or clotting of blood are also present in the plasma in an inactive form.

6. Which of the following is not a formed element?
a) Erythrocytes
b) Leucocytes
c) Platelets
d) Lymph
Answer: d
Clarification: Erythrocytes, leucocytes and platelets are collectively called as formed elements. They constitute nearly 45% of the blood. A reduction in these number can lead to numerous disorders.

7. RBCs are formed in the thymus.
a) True
b) False
Answer: b
Clarification: RBCs are formed in the red bone marrow in the adults. RBCs are devoid of the nucleus in most of the mammals and are biconcave in shape. They have a red coloured iron-containing pigment called haemoglobin.

8. What is the average life span of RBCs?
a) 120 seconds
b) 120 hours
c) 120 days
d) 120 weeks
Answer: c
Clarification: RBCs have an average life span of about 120 days after which they are destroyed in the spleen which is also known as the graveyard of RBCs. These molecules play a significant role in the transport of gases.

9. What is the colour of leucocytes?
a) White
b) Black
c) Red
d) Colourless
Answer: d
Clarification: Leucocytes which are also known as white blood cells because they are colourless in nature as they lack haemoglobin. They are nucleated and are relatively lesser in number as compared to RBCs.

10. WBCs are characterised into 4 main categories.
a) True
b) False
Answer: b
Clarification: WBCs are characterised into 2 main categories- granulocytes and agranulocytes. Neutrophils, eosinophils and basophils are different types of granulocytes while lymphocytes and monocytes are the agranulocytes.

11. Which of the following are the most abundant in WBCs?
a) Neutrophils
b) Basophils
c) Eosinophils
d) Lymphocytes
Answer: a
Clarification: Neutrophils are the most abundant cells of the total WBCs as they constitute about 60-65 per cent of the total. Basophils are the least amongst as they constitute only 0.5-1 per cent of the total WBCs.

12. Which of the following is not secreted by basophils?
a) Histamine
b) Serotonin
c) Heparin
d) Serum
Answer: d
Clarification: Basophils secrete histamine, serotonin and heparin which are involved in the inflammatory reactions. Histamine acts as a vasodilator while serotonin acts as a vasoconstrictor.

13. Which of the following WBCs are involved in allergic reactions?
a) Basophils
b) Eosinophils
c) Neutrophils
d) Monocytes
Answer: b
Clarification: Eosinophils resist infections and are also associated with allergic reactions. Neutrophils and monocytes are phagocytic cells which destroy foreign organisms entering the body.

14. Lymphocytes constitute how much per cent of the total WBCs?
a) 10-15%
b) 20-25%
c) 40-50%
d) 56%
Answer: b
Clarification: Lymphocytes constitute for about 20-25% of the total WBCs. These are of two major types-B and T forms. Both B and T lymphocytes are responsible for the immune responses of the body.

15. Platelets are produced from which of the following cells?
a) Erythrocytes
b) Thrombocytes
c) Megakaryocytes
d) Lymphocytes
Answer: c
Clarification: Platelets are also called thrombocytes which are the cell fragments produced from megakaryocytes which are the special cells in the bone marrow.

Biology Multiple Choice Questions on “Regulation of Excretory System”.

1. Which of these are not involved in the regulation of kidney function?
a) Hypothalamus
b) Heart
c) JGA
d) Spleen
Answer: d
Clarification: The functions of the kidneys are regulated by several organs of the body, such as the hypothalamus, the heart and the JGA or the juxtaglomerular apparatus, and some of their hormones.

2. Which of these do not activate osmoreceptors?
a) Blood volume
b) Body fluid volume
c) Homoeostasis
d) Ionic concentration
Answer: c
Clarification: Osmoreceptors are activated by the blood volume, the body fluid volume and the ionic concentration. When these elements are within the normal range, or during homeostasis, the osmoreceptors are not active.

3. What is another name for ADH?
a) Oxytocin
b) Noradrenaline
c) Vasopressin
d) Ghrelin
Answer: c
Clarification: Another name for ADH or the antidiuretic hormone is vasopressin. It is released from the pituitary gland. The functions of ADH or vasopressin include prevention of diuresis and increasing blood pressure.

4. Where is vasopressin released from?
a) Neurohypophysis
b) Pineal gland
c) Adrenal gland
d) Pancreas
Answer: a
Clarification: Vasopressin or the antidiuretic hormone (ADH) is released from the neurohypophysis or the posterior lobe of the pituitary gland. Oxytocin is also released from here. ADH prevents diuresis.

5. Which of these is not a function of ADH?
a) Stimulates water reabsorption
b) Decreases blood pressure
c) Prevents diuresis
d) Decreases perspiration
Answer: b
Clarification: ADH or the antidiuretic hormone is also known as vasopressin. Vasopressin stimulates water reabsorption from the kidneys, prevents diuresis, decreases perspiration and increases blood pressure.

6. Which of these hormones do not lead to the constriction of blood vessels?
a) Epinephrine
b) Angiotensin II
c) ANF
d) ADH
Answer: c
Clarification: Epinephrine, which is released from the adrenal medulla, ADH or vasopressin, which is released from the posterior pituitary gland and angiotensin II lead to the constriction of blood vessels. They are vasoconstrictors.

7. Which of the following can increase GFR?
a) Increase in blood pressure
b) Decrease in blood pressure
c) Increased Bowman’s capsule hydrostatic pressure
d) Ureteral constriction
Answer: a
Clarification: GFR or the glomerular filtration rate of the kidneys can be increased by increasing the blood pressure. The higher the pressure with which blood flows through the glomerulus, the higher is the rate of filtration.

8. On which of these does ADH act upon?
a) Glomerulus
b) Loop of Henle
c) PCT
d) Collecting duct
Answer: d
Clarification: ADH or the antidiuretic hormone acts upon the latter parts of the nephron to increase reabsorption and prevent diuresis. Hence, ADH or vasopressin mainly acts upon the DCT and the collecting duct.

9. A fall in GFR can stimulate the juxtaglomerular cells to release which hormone from the kidney?
a) Angiotensinogen
b) ADH
c) Renin
d) Angiotensin I
Answer: c
Clarification: A fall in the GFR or the glomerular filtration rate leads to the release of renin from the kidney. Renin converts the inactive angiotensinogen present in blood to its active form, angiotensin I.

10. Aldosterone decreases the reabsorption of sodium ions. True or false?
a) True
b) False
Answer: b
Clarification: Aldosterone is a hormone which is released from the adrenal cortex. It increases the reabsorption of sodium ions and water from the latter parts of the nephrons, such as the DCT and the collecting tube.

11. Which of these hormones converts angiotensinogen to angiotensin I?
a) Aldosterone
b) ADH
c) Angiotensin II
d) Renin
Answer: d
Clarification: Renin is a hormone released by the juxtaglomerular cells of the kidney when there is a fall in the glomerular filtration rate (GFR). It converts the inactive angiotensinogen present in blood to angiotensin I.

12. Which of these hormones activates the adrenal cortex to release aldosterone?
a) ADH
b) Angiotensinogen
c) Angiotensin II
d) Angiotensin I
Answer: c
Clarification: When the GFR decreases, the juxtaglomerular cells of the kidney release renin, which converts angiotensinogen to angiotensin I and further to angiotensin II. Angiotensin II activates the adrenal cortex to release aldosterone.

13. Which of these hormones can decrease blood pressure?
a) Epinephrine
b) ADH
c) ANF
d) Angiotensin II
Answer: c
Clarification: Angiotensin II, epinephrine and ADH or the antidiuretic hormone or vasopressin are vasoconstrictors. They can increase blood pressure. ANF or the Atrial Natriuretic Factor is a vasodilator and can decrease blood pressure.

14. Which of these hormones acts as a check on the renin-angiotensin mechanism?
a) ANF
b) ADH
c) Renin
d) Angiotensinogen
Answer: a
Clarification: ANF or the Atrial Natriuretic Factor is a vasodilator and can decrease blood pressure. It acts as a check on the renin-angiotensin mechanism that is activated when the glomerular filtration rate decreases.

15. Where is aldosterone released from?
a) Pituitary gland
b) Adrenal cortex
c) Pineal gland
d) Adrenal medulla
Answer: b
Clarification: Aldosterone is released from the zona glomerulosa of the adrenal cortex. It is a mineralocorticoid hormone that increases the reabsorption of sodium ions and water from the distal parts of the nephron.

Biology Online Quiz for AIIMS Exam on “Neural Control and Coordination – Eye-2”.

1. What is the inner layer of the eye known as?
a) Sclera
b) Cornea
c) Choroid
d) Retina
Answer: d
Clarification: Each eyeball is surrounded by three layers. The outermost protective layer is the sclera. The middle one is known as choroid. The innermost layer is the retina. It contains light-sensitive photopigments.

2. Which of these structures hold the lens in place?
a) Cartilage
b) Tendons
c) Ligaments
d) Adherens junctions
Answer: c
Clarification: The lens present in the eye is a transparent crystalline structure through which light passes before it falls on the retina. The lens is held in place by the ligaments which are attached to the ciliary body.

3. Which of these is surrounded by the iris?
a) Cornea
b) Sclera
c) Pupil
d) Lens
Answer: c
Clarification: The iris is a continuation of the ciliary body. It is a part of the choroid. The pupil, which is the aperture located just in front of the transparent lens, is surrounded by the pigmented and opaque iris.

4. Which of these cells are not present on the retina?
a) Mast cells
b) Photoreceptor cells
c) Ganglion cells
d) Bipolar cells
Answer: a
Clarification: The retina is the innermost layer surrounding the eye. It contains three types of neural cells-the ganglion cells, the bipolar cells and the photoreceptor cells. The light entering the eye falls on the retina.

5. Which of these statements is false regarding photopigments of the eye?
a) Scotopic vision is a function of rods
b) Visual purple is a derivative of rhodopsin
c) They are light sensitive proteins
d) There are three types of cones
Answer: b
Clarification: Rods and the three types of cones are the photoreceptor cells of the retina. Photopigments are light sensitive proteins. Scotopic vision is a function of rods. Visual purple is also called rhodopsin.

6. To which of these colors are the cone cells of the eye unresponsive?
a) Red
b) Blue
c) Yellow
d) Green
Answer: c
Clarification: Rods and cones are the photoreceptor cells of the retina. There are three types of cone cells which are responsive to three different colors of light. These colors are red, blue and green, but not yellow.

7. The sensation of what color is produced when all cones are stimulated equally?
a) White
b) Black
c) Yellow
d) Purple
Answer: a
Clarification: Each type of cone cell is responsive to different colors of light and various degrees of combinations give sensations of different colors. when all cones are stimulated equally, a sensation white light is perceived.

8. What is the point of exit of optic nerves and entry of blood vessels in the eye?
a) Choroid
b) Fovea
c) Macula lutea
d) Blind spot
Answer: d
Clarification: The point on the retina from which optic nerves exit the eye and through which retinal blood vessels enter the eye is known as the blind spot. No photoreceptor cells are present in this region.

9. In which of these structures are cone cells densely packed?
a) Choroid
b) Blind spot
c) Fovea
d) Cornea
Answer: c
Clarification: Cone cells are densely packed in the fovea, which is the central pit of the macula lutea. The macula lutea is a yellow-pigmented region present near the center of the retina, which is the innermost layer of the eye.

10. The space between the cornea and the lens is called the vitreous chamber. True or false?
a) True
b) False
Answer: b
Clarification: The space between the cornea and the lens is known as the aqueous chamber. It contains a fluid known as aqueous humor. The space between the lens and the retina is known as the vitreous chamber.

11. Which of these is not a protein?
a) Iodopsin
b) Rhodopsin
c) Opsin
d) Retinal
Answer: d
Clarification: Iodopsin and rhodopsin are photosensitive pigments which are proteinaceous in nature. Opsin is also a protein. However, retinal is not a protein. It is an aldehyde of vitamin A.

12. In which of these structures is visual acuity the greatest?
a) Lens
b) Blind spot
c) Fovea
d) Cornea
Answer: c
Clarification: Visual acuity or resolution is the greatest at the fovea. The fovea is the central pit of the macula lutea, which is a yellow-pigmented region of the retina. The fovea contains a large number of cone cells.

13. Which of these does not take place when light falls on the photopigments of the eye?
a) Opsin undergoes conformational changes
b) Action potentials are generated in the ganglion cells
c) Retinal and opsin bind together
d) Potential differences are generated in the photoreceptor cells
Answer: c
Clarification: When light falls on the photopigments, retinal and opsin dissociate and opsin undergoes conformational changes. Potential differences are generated in the photoreceptor cells which lead to action potentials being generated in the ganglion cells.

14. Which of these structures are present on the retina?
a) Macula lutea
b) Macula densa
c) Macula adherens
d) Macula flava
Answer: a
Clarification: The retina is the innermost layer that surrounds the eye. It contains a yellow-pigmented region near its center at the posterior pole of the eye known as the macula lutea. The central pit of the macula lutea is the fovea.

15. Identify the structure in the given diagram.

a) Lens
b) Cornea
c) Iris
d) Pupil
Answer: b
Clarification: The given diagram is that of the cross section of the eye. The indicated structure is present at the anterior pole of the eye, on the outermost layer called sclera. It is identified to be the cornea.

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Biology Multiple Choice Questions on “Biological Classification – Protista – 1”.

1. Protists survive in ________
a) dry desert
b) aquatic regions
c) dry mountains
d) hot hills
Answer: b
Clarification: Protists survive in aquatic regions. They can either survive in fresh water lakes, large oceans, deep seas and marshy areas etc. This is because their body is adapted to survive in areas with low oxygen concentration.

2. Which among the following comprises of animal like protists?
a) Protozoans
b) Chrysophytes
c) Slime molds
d) Dianoflagellates
Answer: a
Clarification: Since, Protozoans are mobile and can ingest food into their body they resemble animals. Some of the protozoans follow holozoic nutrition like that of animals. Therefore, Protozoans are animal like protists.

3. Diatoms are grouped under _________
a) Chrysophytes
b) Protozoans
c) Dianoflagelletes
d) Euglenoids
Answer: a
Clarification: Diatoms are grouped under Chrysophytes. Chrysophytes comprise of golden algae, diatoms and plant like protists etc. It’s because of the golden-yellow color of the species they are named as Chrysophytes.

4. Cell wall in diatoms is made of _______
a) Chitin
b) Pectin
c) Silica
d) Cellulose
Answer: c
Clarification: Cell wall in diatoms is made up of Silica. It’s a double shelled cell wall that fits exactly into each other like the lid of a box. Cell wall of diatoms remains in the earth even after they die and accumulate to form diatomaceous earth.

5. Diatomaceous earth can be used as a pest control because _________
a) it is porous
b) it contains silica which is poisonous for pests when eaten and therefore they die
c) it snatches out lipids from the outermost waxy layer of pests called cuticle and makes them dry which results in their death
d) it acts as anesthesia when given in minor quantities but pests die when large quantities are in taken
Answer: c
Clarification: Diatomaceous earth is used in pest control and grain storage. This is because they are abrasive in nature which snatches out lipids from the outermost layer of pests called cuticle and makes them dry which results in their death.

6. Diatoms store food as _______
a) Starch
b) Glucose
c) Oil
d) Fructose
Answer: c
Clarification: Diatoms store food as oil. Plants store their food as starch. Diatoms are the main food producing bodies in oceans. They prepare food by photosynthesis.

7. Chrysophytes contain chlorophyll or carotene or xanthophyll in them. Their cell wall is rigid and is made up of chitin.
a) True
b) False
Answer: b
Clarification: Chrysophytes contain chlorophyll or carotene or xanthophyll in them. Chrysophytes attain color due to these pigments present in them. Their cell wall is rigid and is made up of Cellulose/ Pectin/ Silica.

8. Cell wall in dianoflagelllates contain _______
a) Chitin
b) Cortex
c) Silica
d) Pectin
Answer: b
Clarification: Dianoflagellates have a complex cell wall made up of cortex. They also possess light sensitive organelle in their cell. Eye spot is found in some of them. Erythropsidium is known to have smallest eye.

9. Dianoflagellates contain ________
a) two flagella with both being transversal
b) two flagella with both being longitudinal
c) two flagella with lone being longitudinal and other being transversal
d) three flagella with one being along x-axis, other being along y-axis and the third one being along z-axis
Answer: c
Clarification: Dianoflagellates contain two flagella with lone being longitudinal and other being transversal. These two flagella help them for their movement and rotation.

10. Dianoflagellates are plant like protists.
a) True
b) False
Answer: b
Clarification: Dianoflagellates are neither plant nor animal like protists. This is because they perform both photosynthesis and locomotion. Therefore, they are neither plants nor animals.

11. What is red tide?
a) Accumulation of cell wall deposits of red algae is called red tide
b) Accumulation of red blood cells in water
c) Coloration of water due to rapid multiplication of red dianoflagellates
d) Spread of chrysophytes due to rapid reproduction
Answer: c
Clarification: Red tide is the coloration of water due to very rapid multiplication of red dianoflagellates. Chemicals released due to this rapid growth are harmful for aquatic life.

12. Which among the following is responsible for red tide?
a) Gonyaulax
b) Udinium
c) Noctiluca
d) Golden algae
Answer: a
Clarification: Red tide is the coloration of water due to very rapid multiplication of red dianoflagellates like Gonyaulax. Chemicals released due to this rapid growth are harmful for aquatic life.

13. Which among the following belong to plankton?
a) Dianoflagellates
b) Chrysophytes
c) Euglenoids
d) Protozoans
Answer: b
Clarification: Chrysophytes are found in aquatic habitats. They are present in fresh water as well as marine. Chrysophytes Are microscopic in nature and float in water currents like planktons.

14. Protists are unicellular eukaryotes.
a) True
b) False
Answer: b
Clarification: All the unicellular eukaryotes are placed in Protista. But all protists are not unicellular. There are few protists that are multi-cellular. But all the protists are eukaryotic organisms.

15. Desmids belong to ________
a) Dianoflagellates
b) Chrysophytes
c) Euglenoids
d) Protozoans
Answer: b
Clarification: Chrysophytes comprise of diatoms and golden algae (desmids). Desmids are unicellular eukaryotes and can prepare their own food by photosynthesis. Desmids reproduce both by sexually and asexually.

Botany Question Bank on “Flowering Plants Morphology – Fruit and the Seed-2”.

1. Dicotyledon seeds have two seed leaves.
a) True
b) False
Answer: a
Clarification: Dicotyledon seeds have two seed leaves. The word cotyledon means seed leaves. When a dicotyledonous seed germinates it initially gives rise to two seed leaves whereas in monocotyledonous seed only a single leaf arises.

2. Which among the following is incorrect about structure of the seed?
a) Testa and tegmen are the two layers of a seed coat
b) Testa and tegmen are closely attached that they can’t be separated unless soaked in water
c) Seed coat provides protection to the embryo
d) Testa is the thin inner layer and tegmen is the thick outer layer of a seed coat
Answer: d
Clarification: Testa and tegmen are the two layers of a seed coat. These are so closely attached that they can’t be separated unless soaked in water. Testa is the thick outer layer and tegmen is the thin inner layer of a seed coat .Seed coat provides protection to the embryo.

3. A scar on seed coat through which seed is attached to the fruit is called ________
a) Cotyledons
b) Seed coat
c) Hilum
d) Micropyle
Answer: c
Clarification: A scar on seed coat through which seed is attached to the fruit is called Hilum. The hilum on a bean seed is called an eye. It marks the former place of attachment of a seed.

4. Which among the following is not correct about embryo inside the seed?
a) An embryo contains cotyledons, radicle and plumule
b) Cotyledons store food and provide nourishment to the developing plumule and radicle
c) A plumule develops into roots
d) Cotyledons are also called as seed leaves
Answer: c
Clarification: An embryo contains cotyledons, radicle and plumule. Cotyledons store food and provide nourishment to the developing plumule and radicle. A plumule develops into roots. Cotyledons are also called as seed leaves.

5. Endosperm provides nourishment to a developing embryo and cotyledons provide nourishment to the developing radicle and plumule.
a) True
b) False
Answer: a
Clarification: Endosperm provides nourishment to a developing embryo and cotyledons provide nourishment to the developing radicle and plumule. Endosperm sometimes can be completely digested and absorbed before the seed gets detached.

6. Which among the following is incorrect about structure in a monocotyledon seed?
a) A monocotyledonous seed mainly comprises of seed coat, endosperm and aleurone layer
b) Seed coat is due to fusion of pericarp
c) Endosperm comprises of starch required for the nourishment of the endosperm
d) Special tissue surrounding the endosperm is called the seed coat
Answer: d
Clarification: A monocotyledonous seed mainly comprises of seed coat, endosperm and aleurone layer. Seed coat is due to fusion of pericarp. Endosperm comprises of starch required for the nourishment of the endosperm. Special tissue surrounding the endosperm is called the aleurone laer.

7. A single cotyledon is also termed as __________
a) Scutellum
b) Aleurone
c) Epicarp
d) Endocarp
Answer: a
Clarification: A single cotyledon i.e. a monocotyledon is also termed as scutellum. A scutellum consists of the embryonic shoot called plumule and the embryonic root called radicle. They get their nourishment from the endosperm in the initial stage and from the cotyledons during their development into a shoot system.

8. Embryonic shoot is covered by a protective layer called _________
a) Coleoptile
b) Coleorrhiza
c) Scutellum
d) Aleurone
Answer: a
Clarification: A scutellum contains an embryonic shoot and an embryonic root called as plumule and radicle respectively. The embryonic shoot is covered by a protective layer called coleoptile.

9. Embryonic root is covered by a protective layer called ________
a) Coleoptile
b) Coleorrhiza
c) Scutellum
d) Aleurone
Answer: b
Clarification: A scutellum consists of an embryonic root and an embryonic shoot called as radicle and plumule respectively. Embryonic root is covered by a protective layer called coleorrhiza.

10. Which among the following is correct about the structure of a monocotyledon?

a) a-Endosperm; b-Seed coat; c-Aleurone layer; d-Scutellum; e-Coleoptile; f-Radicle; g-Coleorhiza
b) a-Scutellum; b-Seed coat; c-Aleurone layer; d-Endosperm; e-Coleoptile; f-Plumule; g-Coleorhiza
c) a-Scutellum; b-Seed coat; c-Aleurone layer; d-Endosperm; e-Coleorhiza; f-Plumule; g-Coleoptile
d) a-Endosperm; b-Seed coat; c-Aleurone layer; d-Scutellum; e-Coleorhiza; f-Plumule; g-Coleoptile
Answer: a
Clarification: Endosperm provides nourishment to the embryo. Seed coat protects the embryo. Aleurone layer surrounds the endosperm and gives protection. A monocotyledon is also called as Scutellum. Coleoptile protects the plumule and coleorhiza protects the radicle.

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