Explore topic-wise MCQs in Biology.

This section includes 37 Mcqs, each offering curated multiple-choice questions to sharpen your Biology knowledge and support exam preparation. Choose a topic below to get started.

1.

Which of the following inhibits \[{{O}_{2}}\] release in light phase  [DPMT 2004]

A. PMA
B. Zeatin
C. DCMU
D. None of these
Answer» D. None of these
2.

The most effective wavelength of visible light in photosynthesis is in the region of [AFMC 1989, 2003; MP PMT 1989, 2000; CPMT 1990, 2000; DPMT 1986, 87, 2004; CBSE PMT 1999; RPMT 1999; Kerala CET 2003]

A. Violet
B. Green
C. Yellow
D. Red
Answer» E.
3.

Emmerson defined 'red drop' as a decline in photosynthesis also termed Emmerson's effect. It appears at

A. 460 nm wavelength
B. 630 nm wavelength
C. 680 nm wavelength
D. 680 nm wavelength
Answer» E.
4.

Under conditions of constant illumination, the compensation period for a whole aquarium would be of infinite length when

A. The biomass of animals equals the biomass of plants
B. The respiratory exchanges of the animals are equal to the photosynthetic exchanges of the plants
C. The oxygen intake of the animals equals of oxygen output of photosynthesis
D. The carbon dioxide output of the animals and plants equals to the photosynthetic intake of the plants
Answer» E.
5.

If water supply to the plant is extremely meagre to as to cause wilting of leaves, the rate of photosynthesis may

A. Increase
B. Decrease
C. First increase than decrease
D. First decrease than increase
Answer» C. First increase than decrease
6.

Warburg studied his effect on

A. Chlamydomonas
B. Chlorella
C. Volvox
D. All the above
Answer» C. Volvox
7.

What plant is used in an experiment commonly performed in laboratory in demonstrate evolution of oxygen in photosynthesis [RPMT 1997]

A. Sunflower
B. Hydrilla
C. Croton
D. Balsam
Answer» C. Croton
8.

The thylakoids are removed and kept in a culture medium containing\[C{{O}_{2}}\]and\[{{H}_{2}}O\]. If the setup is exposed to light, hexose sugars are not formed as the end product. The most appropriate reason for this will be that [AIIMS 1980, 85]

A. Carbon assimilation cannot take place
B. The pigments (P-700 and P-680) are not linked
C. Enzymes are not available
D. The light trapping device is not functional
Answer» D. The light trapping device is not functional
9.

The path of\[C{{O}_{2}}\]in the dark reaction of photosynthesis was successfully traced by the use of the following or The dark reaction is traced by [CPMT 1990; MP PMT 1987; BHU 1992]

A. \[{{O}_{2}}^{18}\]
B. \[{{C}^{14}}{{O}_{2}}\]
C. \[{{p}^{36}}\]
D. X-rays
Answer» C. \[{{p}^{36}}\]
10.

Sedohaptulose is a carbohydrate having

A. 3 carbon atoms
B. 2 carbon atoms
C. 4 carbon atoms
D. 7 carbon atoms
Answer» E.
11.

Radioactive\[{{C}^{14}}\]is given to\[C{{O}_{2}}\]and released to atmosphere. This\[C{{O}_{2}}\]is taken by RuBP in a\[{{C}_{3}}\]plant. First radioactive\[{{C}^{14}}\]is seen in which compound [Manipal 2005]

A. PGAL
B. PEP
C. RMP
D. PGA
Answer» E.
12.

The first step in dark reaction of photosynthesis is [CPMT 2004]

A. Formation of ATP
B. Ionization of water
C. Attachment of \[C{{O}_{2}}\] to a pentose sugar
D. Excitement of electron of chlorophyll by a photon of light
Answer» D. Excitement of electron of chlorophyll by a photon of light
13.

Carbon dioxide is fixed in [MP PMT 1999]

A. Light reaction
B. Dark reaction
C. Aerobic respiration
D. Anaerobic respiration
Answer» C. Aerobic respiration
14.

Dark reaction of photosynthesis take place in [CPMT 1986, 90; RPMT 1995; MP PMT 2000]

A. Grana
B. Stroma
C. Matrix
D. Cytoplasm
Answer» C. Matrix
15.

In\[{{C}_{4}}\]plants,\[C{{O}_{2}}\]combine with PEP in presence of [CPMT 1990]

A. PEP carboxylase
B. RuBP carboxylase
C. RuBP oxygenase
D. Hydrogenase
Answer» B. RuBP carboxylase
16.

Which of the following may show photosynthesis in moonlight

A. Some thermal algae
B. Some marine algae
C. Some fresh water algae
D. None of the above
Answer» C. Some fresh water algae
17.

Photosynthesis will proceed upto

A. Limit of light
B. Limit of wind
C. Limit of moisture
D. None of the above
Answer» B. Limit of wind
18.

Bacteriochlorophyll differs from chlorophyll 'a'  in having [CPMT 1989]

A. One pyrrol ring with one hydrogen
B. One pyrrol ring with two hydrogen
C. One pyrrol ring with three hydrogen
D. One pyrrol ring with four hydrogen
Answer» C. One pyrrol ring with three hydrogen
19.

 Photosynthesis consists of essentially two biological reaction systems, one followed by the other, the second of these systems does which of the following [CPMT 1988]

A. Fixes\[C{{O}_{2}}\]
B. Traps light energy
C. Synthesizes starch
D. Works only in the presence of light
Answer» B. Traps light energy
20.

Chlorophyll 'a' is found in [CBSE PMT 1992]

A. All oxygen releasing photosynthetic forms
B. All plants except fungi
C. All higher plants that photosynthesize
D. All photosynthetic prokaryotes and eukaryotes
Answer» B. All plants except fungi
21.

Which of the plants can show CAM cycle

A. Members of graminae
B. Members of cactaceae
C. Members of chenopodiaceae
D. All the above
Answer» C. Members of chenopodiaceae
22.

No. of carboxylation in \[{{C}_{4}}\]cycle is/are [DPMT 2003]

A. 1
B. 2
C. 5
D. 3
Answer» C. 5
23.

How many types of photosynthetic cells occur in\[{{C}_{4}}\]plant

A. One type
B. Two types
C. Four types
D. Eight types
Answer» C. Four types
24.

CAM photosynthesis occurs in plants with [MP PMT 1993]

A. Thin green leaves with reticulate venation
B. Thin green leaves with parallel venation
C. Fleshy green leaves
D. Thin coloured leaves
Answer» D. Thin coloured leaves
25.

Which of the following is essential for the normal growth of \[{{C}_{4}}\] plants

A. Silicon (100 m)
B. Vanadium\[(100\mu m)\]
C. Sodium (100 m)
D. Barium (100 m)
Answer» D. Barium (100 m)
26.

Atriplex spongiosa is a

A. \[{{C}_{3}}\]plant
B. \[{{C}_{4}}\]plant
C. CAM plant
D. All the above
Answer» C. CAM plant
27.

Which of the following is a CAM plant

A. Maize
B. Sugarcane
C. Agave
D. Mango
Answer» D. Mango
28.

Which of the following is \[C{{O}_{2}}\] acceptor in \[{{C}_{4}}\] plants [CPMT 1986,2004; AMU 1987; CBSE PMT 1990; BHU 1994, 2000; MP PMT 1996; CPMT 1998; Orissa PMT 2002; BVP 2002]

A. Phosphoenol pyruvate (PEP)
B. Ribulose 1, 5 diphosphate (RuDP)
C. Oxaloacetic acid (OAA)
D. Phosphoglyceric acid (PGA)
Answer» B. Ribulose 1, 5 diphosphate (RuDP)
29.

Which one is a\[{{C}_{4}}\]plant [BHU 1979, 82; DPMT 1984; CBSE PMT 1988; MP PMT 1993, 95]

A. Papaya
B. Pea
C. Potato
D. Maize
Answer» E.
30.

Green bacteria contains

A. Chlorobium chlorophyll-660
B. Chlorobium chlorophyll-650
C. Both [a] and [b]
D. Chlorobium chlorophyll-700
Answer» D. Chlorobium chlorophyll-700
31.

Photosynthetic pigments in bacteria are located in  [Wardha 2005]

A. Thylakoid mambrane
B. Cytoplasm
C. Chloroplast membrane
D. Ribosomes
Answer» B. Cytoplasm
32.

What is the bye-product of bacterial photosynthesis

A. \[{{O}_{2}}\]
B. \[{{H}_{2}}O\]
C. \[S\]
D. \[{{H}_{2}}S\]
Answer» D. \[{{H}_{2}}S\]
33.

Assertion : CAM plants lack structural compartmentation of leaf, as found in\[{{C}_{4}}\]plants. Reason : Stomata of CAM plants are open during the day.

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C. If the assertion is true but the reason is false
D. If both the assertion and reason are false
E. If the assertion is false but reason is true
Answer» D. If both the assertion and reason are false
34.

Assertion : Photorespiration is completed in three cell organelles. Reason : Peroxisomes, glyoxysomes and desmosomes are involved in photorespiration.

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C. If the assertion is true but the reason is false
D. If both the assertion and reason are false
E. If the assertion is false but reason is true
Answer» D. If both the assertion and reason are false
35.

Assertion : Six molecules of\[C{{O}_{2}}\] and twelve molecules of \[NADP{{H}^{+}}+{{H}^{+}}\]and 18 ATP are used to form one hexose molecule. Reason : Light reaction results in formation of \[ATP\]and \[NADP{{H}_{2}}\]  [AIIMS 2002]

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C. If the assertion is true but the reason is false
D. If both the assertion and reason are false
E. If the assertion is false but reason is true
Answer» C. If the assertion is true but the reason is false
36.

Assertion : Sciophytes require higher light intensity than heliophytes. Reason : Sciophytes grow below the canopy of trees.

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C. If the assertion is true but the reason is false
D. If both the assertion and reason are false
E. If the assertion is false but reason is true
Answer» F.
37.

Assertion : Oxidative phosphorylation requires oxygen. Reason : Oxidative photophosphorylation occurs in mitochondria.

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C. If the assertion is true but the reason is false
D. If both the assertion and reason are false
E. If the assertion is false but reason is true
Answer» C. If the assertion is true but the reason is false