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AP Intermediate Botany (BIEAP) study materials
AP Intermediate Botany (BIEAP) study resources

AP Intermediate Botany (BIEAP) practice questions

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Question 1Diversity of Living World and Plant Kingdom

In the five-kingdom classification proposed by R. H. Whittaker, which kingdom includes unicellular eukaryotes such as Euglena and Paramecium that lack a cell wall and show both plant-like and animal-like features?

  1. Fungi
  2. Monera
  3. Protista Correct answer.
  4. Plantae

Explanation

Whittaker's five-kingdom system places all unicellular eukaryotes in the kingdom Protista, regardless of whether they photosynthesise, ingest food, or absorb it. Euglena and Paramecium are classic protists because they are eukaryotic, mostly unicellular, and not organised into the multicellular plant, animal, or fungal body plans.

Question 2Diversity of Living World and Plant Kingdom

A specimen shows a filamentous, branched thallus with no true roots, stems, or leaves, and its cells contain chlorophyll a and b. Which group of algae does this specimen most likely belong to?

  1. Chlorophyceae Correct answer.
  2. Cyanophyceae
  3. Rhodophyceae
  4. Phaeophyceae

Explanation

Green algae of the class Chlorophyceae are characterised by chlorophyll a and b together with a grass-green colour and storage of starch. Their thallus may be unicellular, colonial, or filamentous, and they lack the complex tissue differentiation seen in land plants.

Question 3Diversity of Living World and Plant Kingdom

Which pigment is chiefly responsible for the red colour of Rhodophyceae, allowing these algae to absorb blue-green light at greater depths?

  1. Chlorophyll b
  2. Phycoerythrin Correct answer.
  3. Xanthophyll
  4. Fucoxanthin

Explanation

Red algae owe their colour to the accessory pigment phycoerythrin, which masks the green of chlorophyll and efficiently absorbs blue-green wavelengths that penetrate deeper water. This adaptation lets Rhodophyceae photosynthesise at depths where red light is largely filtered out.

Question 4Diversity of Living World and Plant Kingdom

Which feature distinguishes the class Phaeophyceae from other algal classes most reliably?

  1. Presence of a prokaryotic cell without membrane-bound organelles
  2. Presence of phycoerythrin with storage of floridean starch
  3. Presence of chlorophyll a and c with fucoxanthin and storage of laminarin Correct answer.
  4. Presence of chlorophyll a and b with storage of true starch

Explanation

Brown algae are defined by the pigment combination chlorophyll a and c plus fucoxanthin, together with the reserve food laminarin. These biochemical markers separate Phaeophyceae from green, red, and prokaryotic algal groups more reliably than thallus shape alone.

Question 5Diversity of Living World and Plant Kingdom

In the life cycle of a moss such as Funaria, which structure is the dominant photosynthetic phase?

  1. The sporophyte
  2. The gametophyte Correct answer.
  3. The zygote
  4. The protonema only

Explanation

Bryophytes exhibit a heteromorphic alternation of generations in which the haploid gametophyte is the conspicuous, independent, photosynthetic plant body. The diploid sporophyte remains attached to and nutritionally dependent on the gametophyte.

Question 6Diversity of Living World and Plant Kingdom

Why are bryophytes generally restricted to moist, shaded habitats?

  1. Their vascular tissue cannot transport water under tension
  2. Their gametophyte is always parasitic on the sporophyte
  3. Their flagellated sperm require a film of water to swim to the archegonium Correct answer.
  4. Their stomata cannot close during the day

Explanation

Bryophytes produce biflagellate sperm that must swim through a water film to reach the egg inside the archegonium, so sexual reproduction fails in dry conditions. Their lack of true vascular tissue also limits water transport, reinforcing their dependence on damp environments.

Question 7Diversity of Living World and Plant Kingdom

Which structure in a moss capsule produces the haploid spores?

  1. Archegonia undergoing fertilisation
  2. The seta undergoing meiosis
  3. Spore mother cells undergoing meiosis in the capsule Correct answer.
  4. Antheridia undergoing mitosis in the leafy shoot

Explanation

Inside the moss capsule, diploid spore mother cells undergo meiosis to yield haploid spores that are dispersed to start new gametophytes. The antheridia and archegonia produce gametes, not spores, and the seta is a sterile supporting stalk.

Question 8Diversity of Living World and Plant Kingdom

In the life cycle of a fern such as Nephrolepis, the prothallus is best described as which of the following?

  1. A diploid sporophyte bearing sori on its leaflets
  2. A small, free-living, photosynthetic gametophyte bearing antheridia and archegonia Correct answer.
  3. A spore-producing structure within the sorus
  4. A parasitic gametophyte dependent on the sporophyte

Explanation

The fern prothallus is the independent, haploid gametophyte that grows from a germinating spore and bears both antheridia and archegonia on its underside. It is photosynthetic and free-living, unlike the dependent gametophyte of bryophytes' sporophyte relationship.

Question 9Diversity of Living World and Plant Kingdom

A student examines a sorus on the underside of a fern leaflet. Which process occurs inside the sporangia of that sorus?

  1. Fertilisation producing a zygote
  2. Mitosis producing biflagellate sperm
  3. Mitosis producing haploid gametes directly
  4. Meiosis producing haploid spores Correct answer.

Explanation

Each sporangium in a fern sorus contains spore mother cells that undergo meiosis, giving haploid spores that are released and germinate into gametophytes. Gamete production and fertilisation occur later on the prothallus, not inside the sorus.

Question 10Diversity of Living World and Plant Kingdom

Which of the following features is characteristic of the gymnosperm ovule but absent in the fern ovule-equivalent structure?

  1. A multicellular archegonium containing a single egg
  2. Motile sperm that swim through a water film
  3. A free-living gametophyte that photosynthesises
  4. An integument enclosing the nucellus, with the ovule borne naked on a megasporophyll Correct answer.

Explanation

The gymnosperm ovule is a composite structure in which the nucellus is surrounded by one or more integuments, and the whole ovule sits exposed on a megasporophyll rather than enclosed in an ovary. Ferns do not form true ovules or seeds at all; their gametophyte is free-living.

Question 11Diversity of Living World and Plant Kingdom

In Pinus, pollen grains are transferred to the ovule chiefly by which agency?

  1. Water
  2. Wind Correct answer.
  3. Birds
  4. Insects

Explanation

Pines are anemophilous: they produce enormous quantities of light, winged pollen that is carried by air currents to the ovules. Their inconspicuous cones and lack of nectar or showy petals reflect this reliance on wind rather than animal pollinators.

Question 12Diversity of Living World and Plant Kingdom

Which statement correctly describes the male gametophyte of a flowering plant at the time of pollen release?

  1. It is a single haploid cell that divides only after fertilisation
  2. It is a diploid structure that undergoes meiosis in the pollen tube
  3. It is a multicellular prothallus with antheridia
  4. It is a three-celled structure comprising a tube cell and two male gametes Correct answer.

Explanation

In most angiosperms the pollen grain is shed at the three-celled stage, consisting of a vegetative tube cell and two haploid male gametes formed by mitosis of the generative cell. These gametes are delivered by the pollen tube to the embryo sac for double fertilisation.

Question 13Diversity of Living World and Plant Kingdom

Double fertilisation in angiosperms results in which pair of products?

  1. A diploid zygote and a triploid primary endosperm nucleus Correct answer.
  2. A haploid zygote and a diploid endosperm
  3. A triploid zygote and a diploid endosperm
  4. Two diploid zygotes

Explanation

One male gamete fuses with the egg to give a diploid zygote, while the second fuses with the two polar nuclei to form a triploid primary endosperm nucleus. This is the defining feature of double fertilisation in angiosperms.

Question 14Diversity of Living World and Plant Kingdom

A plant shows the following features: vascular tissue present, seeds enclosed within a fruit, and flowers with a perianth. To which group does it belong?

  1. Pteridophyta
  2. Angiospermae Correct answer.
  3. Gymnospermae
  4. Bryophyta

Explanation

Enclosure of seeds within a fruit derived from the ovary, together with true flowers, is the defining combination for angiosperms. Vascular tissue alone would also fit ferns and gymnosperms, so the fruit and flower are the decisive characters here.

Question 15Diversity of Living World and Plant Kingdom

Which of the following is a monocotyledonous character set?

  1. Parallel venation, fibrous root system, and floral parts in threes Correct answer.
  2. Reticulate venation, tap root system, and floral parts in fours or fives
  3. Naked seeds borne on cone scales
  4. Absence of vascular tissue and a dominant gametophyte

Explanation

Monocots typically show parallel leaf venation, a fibrous root system, scattered vascular bundles in the stem, and floral parts in multiples of three. These features together separate them from dicots, which usually show reticulate venation, a tap root, and floral parts in fours or fives.

Question 16Diversity of Living World and Plant Kingdom

Which of the following best explains why the sporophyte generation is considered dominant in pteridophytes but not in bryophytes?

  1. The pteridophyte sporophyte is independent and bears vascular tissue, whereas the bryophyte sporophyte is dependent and non-vascular Correct answer.
  2. The pteridophyte sporophyte is haploid, whereas the bryophyte sporophyte is diploid
  3. The pteridophyte sporophyte lacks meiosis, whereas the bryophyte sporophyte undergoes meiosis
  4. The pteridophyte gametophyte is parasitic on the sporophyte, whereas the bryophyte gametophyte is free-living

Explanation

In ferns the diploid sporophyte is the conspicuous, long-lived, independent plant with true vascular tissue, while the gametophyte is reduced to a small prothallus. In bryophytes the sporophyte remains attached to and nutritionally dependent on the gametophyte and lacks vascular tissue, so the gametophyte dominates.

Question 17Diversity of Living World and Plant Kingdom

The heterosporous condition, in which a plant produces two kinds of spores, is significant because it is regarded as a precursor to which major evolutionary advance?

  1. The origin of chlorophyll b
  2. The formation of a free-living gametophyte
  3. The seed habit Correct answer.
  4. The development of vascular tissue

Explanation

Heterospory produces small microspores and large megaspores, and retention of the megaspore on the parent sporophyte with the female gametophyte developing inside it leads towards the seed habit. Seed plants such as Selaginella among pteridophytes illustrate this transitional condition.

Question 18Diversity of Living World and Plant Kingdom

Which of the following correctly pairs a plant with its distinctive reproductive structure?

  1. Pinus - archegonium borne on a free-living prothallus
  2. Funaria - sorus on the underside of the leaf
  3. Nephrolepis - cone bearing microsporophylls
  4. Marchantia - gemma cup on the thallus for asexual reproduction Correct answer.

Explanation

Marchantia, a liverwort, produces gemmae inside gemma cups on the dorsal surface of its thallus, enabling asexual reproduction. The other pairings wrongly attach structures of one group to an unrelated plant.

Question 19Diversity of Living World and Plant Kingdom

In the classification of the plant kingdom, which sequence correctly reflects increasing complexity from the simplest to the most advanced group?

  1. Gymnosperms, Angiosperms, Pteridophytes, Bryophytes, Algae
  2. Algae, Pteridophytes, Bryophytes, Angiosperms, Gymnosperms
  3. Bryophytes, Algae, Gymnosperms, Pteridophytes, Angiosperms
  4. Algae, Bryophytes, Pteridophytes, Gymnosperms, Angiosperms Correct answer.

Explanation

The conventional progression runs from thalloid algae through the amphibious bryophytes, then vascular spore-bearing pteridophytes, then seed-bearing gymnosperms, and finally the flowering angiosperms. Each step adds features such as vascular tissue, seeds, and flowers.

Question 20Diversity of Living World and Plant Kingdom

A botanist finds a photosynthetic organism with cells containing a definite nucleus, a single chloroplast with a pyrenoid, and a rigid cell wall, reproducing by binary fission. Which group fits best?

  1. Bacillariophyta
  2. Phaeophyceae
  3. Euglenophyta Correct answer.
  4. Cyanophyta

Explanation

Euglenoids are eukaryotic, unicellular flagellates with a nucleus and chloroplasts, and many reproduce asexually by longitudinal binary fission. Their flexible pellicle and single chloroplast with a pyrenoid are characteristic of Euglenophyta.

Question 21Diversity of Living World and Plant Kingdom

Which feature of the angiosperm embryo sac is correctly matched with its ploidy?

  1. The synergids are triploid
  2. The egg cell is diploid
  3. The antipodal cells are diploid
  4. The two polar nuclei are haploid before fusion Correct answer.

Explanation

The embryo sac is a haploid structure, so the two polar nuclei are haploid until one fuses with a male gamete to form the triploid primary endosperm nucleus. Synergids, antipodals, and the egg are all haploid cells of the female gametophyte.

Question 22Diversity of Living World and Plant Kingdom

Which of the following statements about the economic importance of algae is accurate?

  1. Sargassum is a green alga used as a source of carrageenan
  2. Gelidium and Gracilaria are red algae used as sources of agar Correct answer.
  3. Chlorella is a brown alga used as a source of algin
  4. Volvox is a red alga used as a source of iodine

Explanation

Gelidium and Gracilaria are red algae from which agar, a phycocolloid used in culture media and food, is extracted. Correctly matching each genus to its algal class and product is the key to this question.

Question 23Diversity of Living World and Plant Kingdom

In a gymnosperm such as Pinus, the female gametophyte is best described as which of the following?

  1. A single haploid cell that is released as a spore
  2. A free-living photosynthetic prothallus on the soil surface
  3. A diploid tissue that directly forms the integument
  4. A multicellular haploid tissue retained within the ovule that bears archegonia Correct answer.

Explanation

In seed plants the female gametophyte is retained inside the ovule and is nourished by the parent sporophyte. In Pinus it is a multicellular haploid tissue that develops archegonia containing eggs and later provides nutrition to the developing embryo.

Question 24Diversity of Living World and Plant Kingdom

Which of the following is a correct statement about the sporophyte of a liverwort such as Marchantia?

  1. It is differentiated into a foot, a seta, and a capsule and remains attached to the gametophyte Correct answer.
  2. It is a leafy photosynthetic plant that bears gemma cups
  3. It consists of a prothallus bearing antheridia and archegonia
  4. It is a cone bearing ovules on megasporophylls

Explanation

The liverwort sporophyte is a simple structure with a foot embedded in the gametophyte, a short seta, and a capsule in which meiosis produces spores. It is nutritionally dependent on the gametophyte and is not photosynthetic.

Question 25Plant Morphology and Anatomy

In a dicot root, which tissue layer immediately interior to the endodermis gives rise to lateral roots?

  1. Pericycle Correct answer.
  2. Root hair zone
  3. Epidermis
  4. Pith

Explanation

The pericycle is a parenchymatous layer lying just inside the endodermis; its cells retain the ability to divide and initiate lateral root primordia. The endodermis itself is a single suberized barrier layer and does not produce lateral roots.

Question 26Plant Morphology and Anatomy

Which vascular bundle arrangement is characteristic of a monocot stem in transverse section?

  1. Bundles in a single ring with a continuous cambium
  2. Scattered bundles with no clear cambial ring Correct answer.
  3. Bundles in two rings only at the periphery
  4. A single central bundle surrounded by pith

Explanation

Monocot stems show atactostele organization, where numerous closed collateral bundles are scattered through the ground tissue. Because the bundles lack a continuous cambial ring, secondary thickening by a vascular cambium is not possible.

Question 27Plant Morphology and Anatomy

A leaf in which the lamina is divided into distinct leaflets borne on a common rachis is best described as which type?

  1. Peltate
  2. Sessile
  3. Compound Correct answer.
  4. Simple

Explanation

A compound leaf has its blade divided into separate leaflets, each with its own articulation on the rachis or petiolule. A simple leaf has an undivided lamina even if the margin is deeply lobed.

Question 28Plant Morphology and Anatomy

In the standard floral formula notation, what does the symbol ⊕ placed before the whorl symbols indicate?

  1. Fusion of sepals
  2. Epigynous ovary
  3. Actinomorphic symmetry Correct answer.
  4. Zygomorphic symmetry

Explanation

The circled plus sign denotes actinomorphy, meaning the flower can be divided into mirror-image halves along more than one plane. Zygomorphy is represented by a different symbol, usually a percent sign or similar mark.

Question 29Plant Morphology and Anatomy

Which meristem is responsible for the increase in girth of a dicot stem after primary growth is complete?

  1. Vascular cambium Correct answer.
  2. Intercalary meristem
  3. Apical meristem
  4. Protoderm

Explanation

The vascular cambium is a lateral meristem that produces secondary xylem inward and secondary phloem outward, increasing stem diameter. Apical and intercalary meristems contribute to length, not girth.

Question 30Plant Morphology and Anatomy

A plant structure that develops from an axillary bud and bears nodes, internodes, and leaves is which organ?

  1. Adventitious root
  2. Stem Correct answer.
  3. Stipule
  4. Taproot

Explanation

The stem is the axis bearing nodes, internodes, buds, and leaves, and it commonly arises from an axillary bud during branching. Roots lack nodes and leaves, which distinguishes them from stems.

Question 31Plant Morphology and Anatomy

Which tissue system forms the continuous outer protective covering of a young herbaceous dicot plant?

  1. Periderm
  2. Vascular tissue system
  3. Dermal tissue system Correct answer.
  4. Ground tissue system

Explanation

The dermal tissue system, represented by the epidermis in primary plant bodies, forms the outer protective covering. Periderm replaces epidermis only after secondary growth begins.

Question 32Plant Morphology and Anatomy

A transverse section of a dicot root shows a central core of small xylem elements with phloem strands lying between the xylem arms. Which stele type is present?

  1. Eustele
  2. Siphonostele
  3. Atactostele
  4. Radial protostele Correct answer.

Explanation

In a dicot root the xylem forms a solid central core with alternating phloem strands, which is a radial arrangement of a protostele. Steles with pith or with bundles in a ring are stem patterns.

Question 33Plant Morphology and Anatomy

A section of a woody stem shows a distinct band of small, thick-walled, dark-staining cells just inside the vascular cambium. These cells most likely represent which tissue?

  1. Primary phloem
  2. Collenchyma of the cortex
  3. Secondary xylem formed late in the season Correct answer.
  4. Phellogen

Explanation

Late-season secondary xylem consists of narrow, thick-walled tracheary elements that appear darker and denser, forming the latewood band of an annual ring. Primary phloem and cortex lie far outside the cambium in a woody stem.

Question 34Plant Morphology and Anatomy

In a grass leaf, bulliform cells are large, thin-walled epidermal cells that function mainly to do which?

  1. Secrete resin
  2. Roll the lamina during water stress Correct answer.
  3. Conduct water longitudinally
  4. Store starch for the plant

Explanation

Bulliform cells lose turgor under drought and cause the leaf blade to fold or roll inward, reducing transpiring surface. They are epidermal and are not primarily storage or conductive cells.

Question 35Plant Morphology and Anatomy

Which statement correctly distinguishes a stolon from a rhizome?

  1. A stolon is underground, while a rhizome creeps above soil
  2. A stolon bears no nodes, while a rhizome bears nodes
  3. A stolon stores food, while a rhizome only supports leaves
  4. A stolon grows along the soil surface, while a rhizome grows underground Correct answer.

Explanation

Both are creeping stems with nodes, but the stolon runs above or along the soil surface and the rhizome is typically subterranean. Both can bear scale leaves and adventitious roots at nodes.

Question 36Plant Morphology and Anatomy

A plant has a fruit that develops from a single flower with a single carpel and splits along one suture at maturity. This fruit type is which?

  1. Legume
  2. Caryopsis
  3. Siliqua
  4. Follicle Correct answer.

Explanation

A follicle is a dry, dehiscent fruit formed from one carpel that opens along a single suture. A legume also derives from one carpel but dehisces along two sutures.

Question 37Plant Morphology and Anatomy

In a transverse section of a monocot root, which feature reliably distinguishes it from a dicot root?

  1. Presence of a well-developed pith Correct answer.
  2. Absence of endodermis
  3. Xylem in a solid central core
  4. Presence of a vascular cambium

Explanation

Monocot roots typically have a large central pith surrounded by a ring of alternating xylem and phloem, whereas dicot roots usually have a solid central xylem core. Both root types possess an endodermis and lack a vascular cambium in the primary state.

Question 38Plant Morphology and Anatomy

Which cell type is dead at maturity and provides the main pathway for water conduction in angiosperm wood?

  1. Parenchyma cell
  2. Sieve tube element
  3. Companion cell
  4. Vessel element Correct answer.

Explanation

Vessel elements are dead, hollow cells with lignified walls whose end walls are perforated, forming continuous water-conducting tubes. Sieve elements and companion cells are living phloem components.

Question 39Plant Morphology and Anatomy

A leaf has parallel venation, a sheathing leaf base, and stomata distributed on both surfaces. These features together suggest which group?

  1. Dicot
  2. Fern
  3. Gymnosperm
  4. Monocot Correct answer.

Explanation

Parallel venation and a sheathing leaf base are typical monocot leaf features, and amphistomatous leaves are common in grasses. Dicot leaves usually show reticulate venation and a petiolate base.

Question 40Plant Morphology and Anatomy

The placentation in which ovules are attached to a central column in a multilocular ovary with septa is termed which type?

  1. Basal
  2. Marginal
  3. Axile Correct answer.
  4. Parietal

Explanation

Axile placentation places ovules on a central axis where septa meet in a partitioned ovary, as in tomato and lemon. Parietal placentation lacks septa and places ovules on the ovary wall.

Question 41Plant Morphology and Anatomy

In an anther transverse section, the layer of cells immediately surrounding the pollen sac that nourishes developing microspores is which?

  1. Middle layer
  2. Epidermis
  3. Tapetum Correct answer.
  4. Endothecium

Explanation

The tapetum is the innermost anther wall layer lining the locule and supplying nutrients and sporopollenin precursors to developing microspores. The endothecium and middle layer lie outside the tapetum.

Question 42Plant Morphology and Anatomy

A cross-section shows a stem with a ring of collateral bundles, a distinct endodermis, and a pericycle of alternating sclerenchyma and parenchyma. Which organ is this?

  1. Dicot root
  2. Dicot stem Correct answer.
  3. Monocot stem
  4. Monocot root

Explanation

A ring of collateral bundles indicates a stem eustele, and the presence of an endodermis and pericycle confirms a dicot stem, where these layers persist. Monocot stems lack a distinct endodermis and have scattered bundles.

Question 43Plant Morphology and Anatomy

Which modification is correctly matched with its function?

  1. Tendril of grapevine: climbing support Correct answer.
  2. Haustorium of Cuscuta: food storage
  3. Pneumatophore: photosynthesis
  4. Phylloclade of Opuntia: water absorption

Explanation

The grapevine tendril is a modified stem that coils around supports and aids climbing. Other listed modifications serve different functions than those stated.

Question 44Plant Morphology and Anatomy

In a monocot stem, each scattered vascular bundle is described as closed. What does this mean structurally?

  1. The bundle lacks a cambium between xylem and phloem Correct answer.
  2. The bundle is surrounded by a water-filled cavity
  3. The bundle contains only xylem
  4. The bundle is enclosed by a sclerenchymatous bundle sheath

Explanation

A closed bundle has no vascular cambium between xylem and phloem, so it cannot produce secondary vascular tissue. The bundle sheath is a separate feature and does not define closure.

Question 45Plant Morphology and Anatomy

A stem section reveals a periderm in which the cork cambium has produced several layers of suberized cells outward and a few layers of living cells inward. The inner living cells are which tissue?

  1. Secondary phloem
  2. Vascular cambium
  3. Phelloderm Correct answer.
  4. Phellem

Explanation

The cork cambium (phellogen) produces phellem (cork) outward and phelloderm inward; phelloderm cells are living and parenchymatous. Phellem cells are suberized and dead at maturity.

Question 46Plant Morphology and Anatomy

Which combination of anatomical features would be expected in a hydrophytic leaf?

  1. Thick cuticle and sunken stomata
  2. Large air spaces in the mesophyll and reduced cuticle Correct answer.
  3. Absence of stomata and no aerenchyma
  4. Multilayered palisade and sclerenchymatous hypodermis

Explanation

Hydrophytic leaves typically have abundant aerenchyma for buoyancy and gas exchange and a thin or absent cuticle because water loss is not limiting. Xerophytic leaves show the opposite features.

Question 47Plant Morphology and Anatomy

An ovary is unilocular with ovules attached to the inner wall on a swollen placenta that does not reach the center, and the fruit is a siliqua. Which placentation is present?

  1. Basal
  2. Axile
  3. Free-central
  4. Parietal Correct answer.

Explanation

Parietal placentation places ovules on the ovary wall or on a peripheral placenta in a unilocular ovary, and the siliqua of Brassicaceae is a classic example with a false septum. Free-central placentation would show a central column not connected to the wall.

Question 48Plant Morphology and Anatomy

Which sequence correctly describes the arrangement of tissues from the outside inward in a young dicot root?

  1. Pericycle, cortex, endodermis, epiblema, vascular tissue
  2. Epiblema, cortex, endodermis, pericycle, vascular tissue Correct answer.
  3. Epiblema, endodermis, cortex, pericycle, vascular tissue
  4. Cortex, epiblema, pericycle, endodermis, vascular tissue

Explanation

The young dicot root shows epiblema (epidermis) outside, a broad cortical region, then the endodermis, pericycle, and finally the central vascular cylinder. The endodermis lies inside the cortex, not outside it.

Question 49Cell Biology and Biomolecules

Which organelle is the primary site of ATP synthesis by oxidative phosphorylation in a eukaryotic cell?

  1. Rough endoplasmic reticulum
  2. Golgi apparatus
  3. Mitochondrion Correct answer.
  4. Lysosome

Explanation

The inner mitochondrial membrane carries the electron transport chain and ATP synthase, so oxidative phosphorylation occurs there. The other listed organelles handle secretion, digestion, or protein synthesis rather than bulk ATP production.

Question 50Cell Biology and Biomolecules

A cell is placed in a hypotonic solution. What is the expected immediate response of an animal cell?

  1. It loses water and shrinks
  2. It actively pumps solutes out to stay unchanged
  3. It shows no net water movement
  4. It takes in water and may swell or lyse Correct answer.

Explanation

In a hypotonic solution the external solute concentration is lower than the cytosol, so water enters by osmosis. An animal cell without a rigid wall can swell and eventually burst.