State Exam — General Science
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Showing 11–20 of 37 questions
Q.11 Hard Botany
Which of the following statements about stomatal conductance is correct?
AIt remains constant regardless of humidity
BIt increases with decreasing light intensity
CIt is directly proportional to stomatal aperture and inversely related to diffusion path length
DIt is independent of guard cell turgor pressure
Correct Answer:  C. It is directly proportional to stomatal aperture and inversely related to diffusion path length
Explanation:

Stomatal conductance (gs) is the rate of gas diffusion through stomata, dependent on aperture width and inversely on distance (g = A/L).

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Q.12 Hard Botany
In the electron transport chain of chloroplasts, which complex transfers electrons from water to plastoquinone?
ACytochrome b₆f complex
BPhotosystem II (PSII)
CPhotosystem I (PSI)
DATP synthase
Correct Answer:  B. Photosystem II (PSII)
Explanation:

PSII catalyzes photolysis of water at the oxygen-evolving complex, transferring electrons to plastoquinone in the thylakoid membrane.

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Q.13 Hard Botany
In the light-dependent reactions, where exactly does the photolysis of water occur?
AStroma
BThylakoid membrane (lumen side)
CInner mitochondrial membrane
DCytoplasm
Correct Answer:  B. Thylakoid membrane (lumen side)
Explanation:

Water photolysis occurs in the thylakoid lumen as part of Photosystem II, releasing O2, H+, and electrons that drive the electron transport chain.

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Q.14 Hard Botany
The ratio of ATP to NADPH consumed in the Calvin cycle is:
A1:1
B2:1
C3:2
D2:3
Correct Answer:  C. 3:2
Explanation:

For every 3 turns of Calvin cycle (fixing 3 CO2), 9 ATP and 6 NADPH are used. This gives a ratio of 3:2 (ATP:NADPH).

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Q.15 Hard Botany
The Casparian strip in the endodermis of roots is primarily composed of:
ACellulose and pectin
BSuberin and lignin
CCuticle and wax
DProteins and lipids
Correct Answer:  B. Suberin and lignin
Explanation:

The Casparian strip contains suberin (waxy substance) and lignin, which prevents apoplastic (cell wall) movement of water and minerals, forcing symplastic transport.

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Q.16 Hard Botany
In photosynthesis, the Z-scheme diagram shows the flow of electrons between which two photosystems?
APSI and PSII
BOnly PSII
CCytochrome b6f complex only
DStromal lamellae only
Correct Answer:  A. PSI and PSII
Explanation:

The Z-scheme illustrates electron flow from PSII through the cytochrome b6f complex to PSI, showing how electrons are elevated twice to reach NADP+ reduction.

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Q.17 Hard Botany
The transpiration coefficient (amount of water transpired per unit dry matter produced) is lowest in:
AC3 plants
BC4 plants
CCAM plants
DHydrophytes
Correct Answer:  C. CAM plants
Explanation:

CAM plants have the lowest transpiration coefficient because they open stomata only at night, minimizing water loss while fixing CO2 efficiently.

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Q.18 Hard Botany
Which structure in plant cells is analogous to the centrosome in animal cells?
ACell wall
BPlasmodesmata
CChloroplast
DNucleus
Correct Answer:  B. Plasmodesmata
Explanation:

While plant cells lack true centrosomes with centrioles, plasmodesmata serve similar intercellular communication functions. However, most plant cells lack a distinct MTOC (microtubule-organizing center).

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Q.19 Hard Physics
Which quantum number determines the shape of an orbital?
APrincipal quantum number (n)
BAzimuthal quantum number (l)
CMagnetic quantum number (m)
DSpin quantum number (s)
Correct Answer:  B. Azimuthal quantum number (l)
Explanation:

The azimuthal quantum number (l) determines the shape of the orbital (s, p, d, f)

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Q.20 Hard Physics
A wire of resistance R is stretched to double its length. What is the new resistance?
AR
B2R
C4R
DR/2
Correct Answer:  C. 4R
Explanation:

Resistance R = ρL/A. When length doubles, L becomes 2L and area becomes A/2 (volume constant). New R = ρ(2L)/(A/2) = 4ρL/A = 4R

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