Botany MCQ Quiz - Objective Question with Answer for Botany - Download Free PDF

The correct answer is Water.

Key Points

Xylem:

• Water Transport: Xylem is responsible for the transport of water and dissolved minerals from the roots to other parts of the plant.
• It forms a network of interconnected tubes that extend from the root system to the leaves.
• Structure and Components: Xylem tissue is composed of several types of specialized cells.
• The main conducting cells in xylem are called tracheary elements, which include tracheids and vessel elements. These cells have thick, lignified cell walls that provide structural support and prevent collapse under the tension created during water transport.
• Unidirectional Flow: The movement of water through xylem occurs in a unidirectional manner, primarily driven by transpiration, which is the loss of water vapor through the stomata on the leaves.
• This process creates a negative pressure or tension, pulling water upward from the roots to the upper parts of the plant.

Phloem:

• Nutrient Transport: Phloem is responsible for the transport of organic nutrients, such as sugars, amino acids, and hormones, from the site of production (usually leaves) to other parts of the plant.
• It allows the distribution of these nutrients to areas of growth, storage, or metabolic activity.
• Structure and Components: Phloem tissue consists of several cell types, including sieve tube elements, companion cells, phloem fibers, and phloem parenchyma cells.
• The main conducting cells are the sieve tube elements, which form sieve tubes. These cells lack nuclei and have perforated sieve plates that allow the movement of nutrients between adjacent cells.
• Bidirectional Flow: The movement of nutrients through phloem can occur in both upward (from source to sink) and downward (from sink to source) directions.
• This bidirectional flow is facilitated by pressure gradients and active transport mechanisms. Source tissues, such as mature leaves, produce sugars and load them into the phloem, while sink tissues, such as developing fruits or roots, consume the nutrients.

The correct answer is Thallophyta.

Key Points

• Litmus is a natural dye extracted from lichen, which belongs to the division Thallophyta.
• Thallophyta includes simple, non-vascular plants without true roots, stems, or leaves.
• Lichens are a symbiotic association of algae and fungi, categorized under Thallophyta due to their primitive structure.
• Litmus is commonly used as an acid-base indicator in laboratories due to its color-changing properties.
• It turns red in acidic solutions and blue in basic solutions, making it an essential tool for pH testing.

Additional Information

• Thallophyta:
  • Thallophytes are primarily aquatic or grow in moist habitats.
  • They reproduce through spores and lack a well-defined vascular system.
  • Examples include algae, fungi, and lichens.
• Lichens:
  • Lichens are a mutualistic relationship between algae (providing food through photosynthesis) and fungi (offering protection and water absorption).
  • They are bioindicators of air quality, as they are sensitive to pollution.
• Litmus Indicator:
  • Litmus solution is extracted by processing lichens with solvents.
  • It is one of the oldest and most widely used natural pH indicators.
• Other Natural Indicators:
  • Turmeric: Turns reddish-brown in basic solutions.
  • Red Cabbage Extract: Changes color across a wide pH range.
  • China Rose (Hibiscus): Acts as an indicator in acidic and basic solutions.

The correct answer is Sieve tubes.

Key Points

• The translocation of food (mainly sucrose) in plants occurs through the phloem tissue, specifically the sieve tubes.
• Sieve tubes are elongated cells that are connected end-to-end to form sieve plates, allowing for the movement of food substances in upward and downward directions.
• The process of translocation is energy-dependent and is facilitated by adjacent companion cells that provide the necessary ATP for active transport.
• Companion cells are closely associated with sieve tubes and are responsible for loading and unloading sugars into the sieve elements.
• Translocation in phloem operates based on the pressure-flow hypothesis, which involves the movement of solutes from a source (e.g., leaves) to a sink (e.g., roots or fruits).

Additional Information

• Phloem components:
  • Sieve tubes: Conducting elements responsible for translocation.
  • Companion cells: Support sieve tubes metabolically and regulate solute movement.
  • Phloem parenchyma: Stores food and other substances.
  • Phloem fibers: Provide mechanical support.
• Translocation mechanism:
  • Source: Regions where sugars are synthesized (e.g., leaves).
  • Sink: Regions where sugars are stored or utilized (e.g., roots, fruits).
  • Energy is required for loading and unloading sugars into sieve tubes via companion cells.
• Pressure-flow hypothesis:
  • Describes the movement of sucrose and other solutes in the phloem.
  • High pressure develops at the source due to sugar loading and water influx.
  • Low pressure at the sink facilitates the movement of sugars along the concentration gradient.
• Comparison with xylem:
  • Phloem transports food; xylem transports water and minerals.
  • Phloem flow is bidirectional; xylem flow is unidirectional (upward).

The correct answer is Meristem.

• Permanent tissues are derived from meristematic tissue once they lose the ability to divide.
• They are classified as simple and complex tissues.
• Parenchyma, collenchyma and sclerenchyma are three types of simple tissues.
  • Parenchyma tissue is involved in photosynthesis, secretion, food storage, and other activities of plant life.
  • Collenchyma tissue provides support, structure, mechanical strength, and flexibility to the petiole, leaf veins, and stem of young plants, allowing for easy bending without breakage.
  • Sclerenchyma is one of the three types of ground, or fundamental, tissue in plants; the other two types are parenchyma (living thin-walled tissue) and collenchyma (living support tissue with irregular walls).
• Xylem is planted vascular tissue. It transports water and dissolved minerals from the roots to the rest of the plant and also provides physical support.

Additional Information

• Permanent tissues in a plant are those tissues that contain non-dividing cells.
  • The cells are also modified to perform specific functions in the plants.
  • The cells of the permanent tissue are derived from the meristematic tissue. 
  • The permanent tissue cells are also fully differentiated. The cells are large and a definite shape and size.
  • The metabolism that occurs in the cells of the permanent tissue is fairly at a lower rate.
  • The permanent tissue in plants mainly helps in providing support, protection as well as in photosynthesis and conduction of water, minerals, and nutrients. Permanent tissue cells may be living or dead.

The correct answer is Disrupted stomatal apparatus on aerial organs.

Key Points

• Gas exchange in plants primarily occurs through stomata, which are predominantly located on aerial organs like leaves and stems, rather than roots.
• Roots are not major sites for gas exchange, and the absence of a functional stomatal apparatus on aerial organs would directly hinder the plant's ability to exchange gases (O₂ and CO₂).
• The disruption of stomatal function does not significantly affect water absorption in roots, as water uptake is primarily mediated by root hairs and the epiblema layer.
• Stomatal dysfunction would limit photosynthesis and respiration processes, directly impacting plant growth and metabolism.
• This issue contrasts with other options (e.g., root hairs or epiblema cells), which are more relevant to water absorption rather than gas exchange.

Additional Information

• Stomata: Tiny openings on the surface of leaves and stems that regulate gas exchange and water loss through transpiration. They are controlled by guard cells.
• Root Hairs: Extensions of the epidermal cells in roots, responsible for increasing the surface area for water and nutrient absorption from the soil.
• Epiblema: The outermost layer of root cells that aids in water absorption and sometimes forms root hairs for efficient uptake.
• Suberin in Endodermis: A hydrophobic material present in the Casparian strips of endodermal cells, which regulates water and nutrient flow into the vascular system of roots.
• Photosynthesis and Respiration: Processes that depend on gas exchange (CO₂ for photosynthesis and O₂ for respiration), primarily facilitated by stomata in aerial parts of the plant.

Concept:

Photosynthesis: 

• The leaves have a green pigment called chlorophyll.
• It helps leaves to capture the energy of the sunlight.
• This energy is used to synthesise (prepare) food from carbon dioxide and water. Since the synthesis of food occurs in the presence of sunlight, it is called photosynthesis.

In the presence of sunlight Carbon dioxide + water → Carbohydrate + oxygen.

• Some plants, green algae, and cyanobacteria can perform photosynthesis.
• The process of photosynthesis is commonly written as

                   6CO2 + 6H2O + Sun-Light → C6H12O6 + 6O2

Plant cells have a cell wall to protect them and make them rigid structure.

Explanation:

1. Plants convert energy from sunlight into food stored as carbohydrate’s - Correct

2. Plants have chlorophyll. - Correct

3. Plant cells do not have cell walls. - Incorrect.

Additional Information

In the plant cells, there are different components and organelles for specific functions-

• Cell Wall – It is a rigid layer composed of cellulose. It is the outermost layer of the cell, below this cell membrane is present. The primary function of the cell wall is to protect and provide structural support to the cell.
• Cell Membrane – It is a semi-permeable membrane that helps in regulating and the substance for entry and exit inside and outside the cell.
• Nucleus – It is a vital part of the cell as it contains all the information or DNA of the cell and their heredity information for growth and cell division.
• Vacuole – Most of the part of the plant cell is occupied by the vacuole. It is surrounded by Tonoplast. The vital role of the vacuole is to provide support again the pressure of the cell wall.
• Golgi apparatus – They act as a transport system in the cell, as they transport various molecules to a different part of the cell.
• Ribosomes – They are the sites of protein synthesis, also termed as the protein factory of the cell.
• Mitochondrion – They break the complex molecules and produce energy and hence called the powerhouse of the cell.
• Lysosomes – They are termed suicidal bags as they hold the enzymes that are capable to digest the whole cell itself.

The correct answer is Collenchyma.

 Concept:

• Collenchyma is a specialized simple permanent tissue that provides support and flexibility to plants.
  • This tissue is made up of living cells having uneven thickenings of cellulose, pectin, and hemicellulose on the walls.
  • Cells possess chloroplast, then it is involved in manufacturing sugar and starch.
  • Provides tensile strength and flexibility to the plant body.

Explanation:

• Parenchyma- this tissue provides support to plants. It also stores food. So this option is not correct.

• Collenchyma- it allows easy bending of plant parts and provides flexibility. So the option is correct.
• Sclerenchyma- this tissue makes the plant hard and stiff. It is present in the husk of a coconut. So the option is not correct.

Additional Information

• Parenchyma is the most common and abundant tissue in plants which is made up of thin-walled living cells having a distinct nucleus.
  • The main function of parenchyma is to store and assimilate food. Hence, they are referred to as food storage tissues.
  • Serves as a packing tissue to fill the spaces between other tissues and maintain the shape and firmness of the plant.
  • Stores waste products of plants.
• Sclerenchyma is a lignified supportive tissue made up of thick-walled and lignified cells.
  • Provides mechanical strength to the plant.

The correct answer is Calyx.

Key Points

• Flowers contain the plant’s reproductive structures.
• A typical flower has four main parts - or whorls - known as the calyx, corolla, androecium, and gynoecium.
• The outermost whorl of the flower has green, leafy structures known as sepals.
  • The sepals, collectively called the calyx, help to protect the unopened bud.

Important Points

• The second whorl is comprised of petals - usually, brightly coloured - collectively called the corolla.
• The number of sepals and petals varies depending on whether the plant is a monocot or dicot. 
  • In monocots, petals usually number three or multiples of three; in dicots, the number of petals is four or five, or multiples of four and five.
  • Together, the calyx and corolla are known as the perianth.
• The third whorl contains the male reproductive structures and is known as the androecium.
  • The androecium has stamens with anthers that contain the microsporangia.
• The innermost group of structures in the flower is the gynoecium, or the female reproductive component(s).
• The carpel is the individual unit of the gynoecium and has a stigma, style, and ovary.
  • A flower may have one or multiple carpels.

The correct answer is Parasite.

Important Points

• Cuscuta is a parasitic plant.
• Since Cuscuta does not have chlorophyll, it cannot synthesize its own food by photosynthesis.
• It uses the nutrients of host plants for its growth.
• Other parasitic plants are - Rafflesia, Viscum, Nuytsia floribunda.
• Parasitic plants cause damage to the host plant.

The correct answer is Chlamydomonas.

• Chlamydomonas is found in stagnant water and on damp soil as well as freshwater, seawater, and even in snow.
• About Chlamydomonas-
  • Class: Chlorophyceae
  • Order: Chlamydomonadales
  • Scientific name: Chlamydomonas
  • Phylum: Chlorophyta
  • Higher classification: Chlamydomonadaceae

The correct answer is the apple tree.

 Key Points

• Apple, (Malus Domestica), the fruit of the domesticated tree Malus Domestica (family Rosaceae), is one of the most widely cultivated tree fruits.
• A scientific name is a formal system of naming species of living things by giving them a name composed of two parts both by using Latin words and they can also be formed by using words from other languages.

 Additional Information

Based on whether plants have a well-differentiated body and the presence or absence of specialized tissues for transport, and the ability to bear seeds Kingdom Plantae (Plant Kingdom) is can be classified into 5 different groups.

• Thallophyta
  • The plant body is not differentiated from roots, stems, and leaves.
  • They are commonly called algae.
• Bryophyta
  • These are small terrestrial plants.
  • They show differentiation in the body design, with stem, leaf-like structures, and root-like structures.
• Pteridophyta
  • The plant body is differentiated into roots, stems, and leaves, apart from having a specialized tissue for conduction.
• Gymnosperms
  • Gymnosperms are plants with naked seeds.
• Angiosperms
  • Angiosperms are seed-bearing plants. Seeds develop inside tissues that get modified to form the fruit of the plant. 

Hence, we can conclude that plants are divided into 5 groups.

The correct answer is Option 2, i.e., Cork. 

• In-Plant tissues, the cell walls of 'cork' are coagulated by 'suberin' which makes them impervious to water & gas molecules. 
• Protective tissues: 
  • These tissues provide fortification to the plant. 
  • They include two basic things which are known as the 'epidermis & cork'.
• The following table shows the components of protective tissues with respective features. 

  Components of Protective tissues	Features
  Epidermis	It is a layer of cell that makes up the outer casing in the plant. At certain places, the stomata perforate the epidermis. The stomata help in loss of gaseous exchange & water
  Cork	It is the external protective tissue that substitutes the epidermal cells in mature roots & stems. Cork cells lack intercellular gaps & lifeless. The cell walls of corks are coagulated by suberin which makes them impervious to water molecules & gas molecules.

Concept:

About Plant Reproduction:

• Sexual Reproduction is defined as the production of a (New organism) from Two-parents by making use of their (Gametes or Sex cells). Plants also have Male and Female sex organs are carried within the (Flower and the Seeds which are inside a Fruit).
• These plants are called (Angiosperms or Flowering plants) as they reproduce by the Sexual reproduction method. 
• Most of the plants contain Reproductive organs of both (Males and Females) in the flowers.

Parts of a flower and their functions:

• Sepals: Protect the unopened flower
• Petals: Maybe brightly colored to attract insects
• Stamens: The male parts of the flower (each consists of an anther held up on a filament)
• Anthers: Produce male sex cells (pollen grains)
• Carpel: Female reproductive part of the flower which consists of ovules (inside which the egg cells ultimately form), ovary, style, and stigma.
• Stigma: The top of the female part of the flower which collects pollen grains
• Ovary: Produces the female sex cells (contained in the ovules)
• Nectary: Produce a sugary solution called nectar, which attracts insect

Explanation:

The swollen bottom part of flower is Carpel.

• The (Male organ part) of a flower is called the (Stamen) and the (Female organ part) of a flower is called (Carpel). It helps in making the (Male Gametes) of the plant and that is present in Pollen grains.
• These Pollen Grains helps in making (Female Gametes or Egg cells) of the plant and are present in Ovules. The (Male Gametes) fertilize the (Female Gametes).
• The fertilized (Egg cells) grow in Ovules and become Seeds.
• When germinated, these Seeds started growing as (new Plants).

The correct answer is leaves

Explanation:

Photosynthesis - Food-Making Process in Plants - 

• In plants, leaves are the food factories.
• Hence, all the raw materials, like water and minerals, carbon dioxide must reach leaves.
• Chlorophyll, the green pigment present in leaves helps to capture the energy of the sunlight to synthesize (prepare) food from carbon dioxide and water.
• The process is called photosynthesis because the synthesis of food occurs in the presence of sunlight. 

Additional Information

Sweet Potato stored food in their root.

But make their food at leaves.