General Science PYQ – Plant Biology

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General Science PYQ – Plant Biology – 34 questions, subject: Science. Every question has the correct answer with a one-line explanation; tap "Show Answer". Free practice for TNPSC, UPSC, SSC, Bank and RRB exams – Shanmugam IAS Academy, Coimbatore.

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1.  
GSHA 2021
Which of the following statement is incorrect regarding blue green algae?

Correct Answer: C [Absence of mucilage around the thallus]

Explanation:

Blue-green algae have mucilage around the thallus, so the statement that mucilage is absent is incorrect.

2.  
District Educational Officer 2023
Match the following:
(a) Carrageenin – 1. Insulation of boilers
(b) Diatomite – 2. Dental impression
(c) Kelps – 3. Irish moss
(d) Alginic acid – 4. Brown Algae

Correct Answer: D [3 1 4 2]

Explanation:

Carrageenin comes from Irish moss, diatomite is used for boiler insulation, kelps are brown algae and alginic acid is used for dental impressions, giving 3 1 4 2.

3.  
Hostel Supdt. cum PTO 2024
The plant group which are popularly called as "Vascular Cryptogams" are

Correct Answer: B [Pteridophytes]

Explanation:

Pteridophytes (ferns) have vascular tissues xylem and phloem but no seeds or flowers, so they are called vascular cryptogams.

4.  
Combined Engineering Subordinate Service 2023
Assertion [A]: Gymnosperms are naked seed plant.
Reason [R]: The ovules are enclosed by Ovary in Gymnosperm plants.

Correct Answer: D [[A] is true but [R] is False]

Explanation:

Gymnosperms are naked-seeded plants because their ovules are not enclosed by an ovary, so the assertion is true and the reason is false.

5.  
VCGS 2022
Which of the following tree is the tallest?

Correct Answer: D [Sequoia]

Explanation:

Sequoia (redwood), a gymnosperm, is the tallest tree in the world, growing over 100 metres.

6.  
Executive Officer Gr. III (HR&CE) 2022
What is the botanical name of Lemon grass?

Correct Answer: D [Cymbopogon citratus]

Explanation:

Lemon grass is botanically Cymbopogon citratus, a source of aromatic oil.

7.  
Fisheries Inspector / SI 2023
The study of particular culture and region to make of use of Indigenous plants is known as

Correct Answer: B [Ethnobotany]

Explanation:

Ethnobotany is the study of how a particular culture or region's people use indigenous plants for food, medicine and rituals.

8.  
Geology Service 2023
National Fossil Wood Park in Tamilnadu is located in

Correct Answer: A [Villupuram]

Explanation:

The National Fossil Wood Park, with 20-million-year-old petrified tree trunks, is at Thiruvakkarai in Villupuram district.

9.  
VAS AHGS 2020
What is the name of cork cambium?

Correct Answer: D [Phellogen]

Explanation:

Cork cambium is called phellogen; it produces cork (phellem) outward and secondary cortex (phelloderm) inward.

10.  
AJ 2023
Xylem tissue is composed of

Correct Answer: D [Tracheids, Fibres, Vessels and Parenchyma]

Explanation:

Xylem is made of tracheids, vessels, xylem fibres and xylem parenchyma, which conduct water and minerals.

11.  
Group 4 2024
Which of the following food material is translocated by phloem loading?

Correct Answer: D [Sucrose]

Explanation:

Food made in leaves is loaded into the phloem and translocated as sucrose, a stable non-reducing sugar.

12.  
CTS (Interview Posts) 2024
In angiosperms Lateral roots originate from

Correct Answer: D [Pericycle]

Explanation:

In angiosperms, lateral roots arise endogenously from the pericycle.

13.  
GSCE 2021
The roots that grows vertically downwards from the lateral branches into the soil is called as

Correct Answer: B [Prop roots]

Explanation:

Prop roots grow vertically down from lateral branches into the soil and support them, as in the banyan tree.

14.  
District Educational Officer 2023
The chief function of velamen tissue in plants

Correct Answer: B [Absorption of moisture from air]

Explanation:

Velamen tissue in the aerial roots of epiphytes like orchids absorbs moisture from the air.

15.  
CTS (ITI Posts) 2024
Match the following:
(a) Bulb – 1. Turmeric
(b) Corm – 2. Potato
(c) Rhizome – 3. Onion
(d) Tuber – 4. Colocasia

Correct Answer: A [3 4 1 2]

Explanation:

Onion is a bulb, colocasia a corm, turmeric a rhizome and potato a tuber, giving 3 4 1 2.

16.  
Field Surveyor 2022
Which one of the following is root parasite plant?

Correct Answer: D [Rafflesia]

Explanation:

Rafflesia is a total root parasite on host roots, whereas Cuscuta is a stem parasite and Viscum and Loranthus are partial stem parasites.

17.  
Group 1 2024
Plants that endures best at lower light intensity are called

Correct Answer: C [Sciophytes]

Explanation:

Plants that grow best in low light or shade are called sciophytes, unlike heliophytes that need strong light.

18.  
FA 2022
What term is used to describe the cultivation of plants without soil?

Correct Answer: D [Hydroponics]

Explanation:

Growing plants without soil in nutrient solution is called hydroponics.

19.  
Combined Engineering Subordinate Service 2023
Which of the following factors are necessary for photosynthesis?

Correct Answer: C [Water, Carbon dioxide, Sunlight, Chlorophyll]

Explanation:

Photosynthesis needs water, carbon dioxide, sunlight and chlorophyll: 6CO2 + 12H2O gives C6H12O6 + 6O2 + 6H2O.

20.  
Fisheries Inspector / SI 2023
Chlorophyll present in the leaf is required for

Correct Answer: A [Photosynthesis]

Explanation:

Chlorophyll absorbs sunlight and supplies the energy for photosynthesis in chloroplasts.

21.  
Fisheries Inspector / SI 2023 · Combined Engineering Subordinate Service 2023
The atmospheric carbon di oxide enters into the plants and fixed through the process called

Correct Answer: A [Photosynthesis]

Explanation:

Atmospheric carbon dioxide enters leaves through stomata and is fixed into carbohydrates in photosynthesis.

22.  
Group 1/1A 2025
Choose the right matches:
(1) Carotenoid – C55H70O5N4Mg
(2) Chlorophyll 'a' – C55H72O5N4Mg
(3) Chlorophyll 'b' – C55H70O6N4Mg
(4) Xanthophyll – C50H70O5Mg

Correct Answer: C [(2) and (3) are correct]

Explanation:

Chlorophyll a is C55H72O5N4Mg and chlorophyll b is C55H70O6N4Mg, whereas carotenoids contain no Mg or N, so (2) and (3) are correct.

23.  
Asst. Public Prosecutor Gr. II 2026
Choose the right statement among types
(1) C4 cycle occurs in Mesophyll cells and Bundle sheath chloroplast
(2) CAM cycle occurs in Mitochondria
(3) Glycolate cycle occurs in Chloroplast, Peroxisomes and Mitochondria
(4) TCA cycle occurs in Vacuole.

Correct Answer: B [(1) and (3) are correct]

Explanation:

The C4 cycle occurs in mesophyll and bundle sheath chloroplasts and the glycolate cycle in chloroplasts, peroxisomes and mitochondria, so (1) and (3) are correct.

24.  
GSCE 2021
Which is used for synthesis of anthocyanin, lignin and other aromatic compounds?

Correct Answer: A [Erythrose]

Explanation:

Erythrose-4-phosphate starts the shikimic acid pathway that gives aromatic compounds such as anthocyanin and lignin.

25.  
Group 2/2A 2025
Carbon serves for the following purpose/purposes in living organisms:
(1) It's a structural component of organic molecule.
(2) Helps to bind with other molecules.
(3) Gives flexibility to the form and function of Biomolecules such as DNA and RNA.

Correct Answer: D [(1), (2) and (3)]

Explanation:

Carbon is tetravalent and forms chains and rings that serve as the structural basis of organic molecules, bind other molecules and give flexibility to DNA and RNA, so all three are correct.

26.  
GSCE 2021
Which one of the following mineral is needed large quantity for plants?

Correct Answer: A [Nitrogen]

Explanation:

Nitrogen is the mineral nutrient needed in the largest quantity by plants, being a part of proteins, nucleic acids and chlorophyll.

27.  
GSHA 2021
Match the following minerals with its deficiency symptoms?
(a) Exanthema in citrus – 1. Zinc
(b) Hooked leaf tip – 2. Copper
(c) Little leaf – 3. Potassium
(d) Curled leaf margin – 4. Calcium

Correct Answer: A [2 4 1 3]

Explanation:

Exanthema in citrus shows copper deficiency, hooked leaf tip calcium, little leaf zinc and leaf margin curling potassium deficiency, giving 2 4 1 3.

28.  
Executive Officer Gr. I (HR&CE) 2024
Identify the Ammonifying bacterium

Correct Answer: A [Bacillus ramosus]

Explanation:

Bacillus ramosus is an ammonifying bacterium that decomposes proteins of dead organisms into ammonia.

29.  
District Educational Officer 2023
'Guttation' takes place through

Correct Answer: A [Hydathode]

Explanation:

Guttation is the loss of water as droplets from hydathodes at leaf tips and margins when root pressure is high and transpiration low.

30.  
VCGS 2022
Which of the following compound induce flowering?

Correct Answer: A [Florigen]

Explanation:

Florigen, formed in leaves and moving to buds, is the hormone believed to induce flowering.

31.  
CEGS 2024
Which of the following is not correctly matched?

Correct Answer: C [Cytokinin – Promotes senescence]

Explanation:

Cytokinin delays senescence rather than promoting it, so that pairing is incorrect.

32.  
Group 1 2022
The first step in the seed germination is imbibition of water which induce the

Correct Answer: D [Resumes metabolic activities]

Explanation:

Imbibition of water softens the seed coat and activates enzymes, so metabolic activities resume as the first step of germination.

33.  
Group 2 2022
Match the following:
(a) Apospory – 1. Development of a sporophyte directly from the gametophyte
(b) Apogamy – 2. Fruit formation without fertilization of ovules
(c) Parthenocarpy – 3. Development of an embryo from an unfertilized egg cell
(d) Parthenogenesis – 4. Development of gametophytes directly from the sporophyte

Correct Answer: C [4 1 2 3]

Explanation:

Apospory is gametophyte from sporophyte, apogamy sporophyte from gametophyte, parthenocarpy fruit without fertilization and parthenogenesis embryo from unfertilised egg: 4 1 2 3.

34.  
GSCE 2021
Match the following:
(a) Zoophily – 1. Vallisneria
(b) Hydrophily – 2. Grass
(c) Entomophily – 3. Canna
(d) Anemophily – 4. Salvia

Correct Answer: D [3 1 4 2]

Explanation:

Zoophily is illustrated by Canna, hydrophily by Vallisneria, entomophily by Salvia and anemophily by grass, giving 3 1 4 2.

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