Biology

Plant Transport and Physiology

1,834 Questions

Access a comprehensive set of questions on plant transport mechanisms and physiological adaptations. Topics include water movement, translocation of food, and plant responses to external stimuli. These biology questions are essential for medical entrance exams and other science competitive tests.

Xylem and phloem transportTranspiration and evaporationPlant adaptationsGeotropic and phototropic responsesWater absorption by rootsRespiration in roots

Plant Transport and Physiology Questions

Multiple choice botany water absorption and ascent of sap in plants factors affecting the transport of water and minerals in plants ascent of sap long distance transport of water

Choose the correct answers from the alternatives given :
In which of the following plants metabolism would be hindered if leaves are coated with vaseline on their upper surface ?

  1. Pistia

  2. VaIlisneria

  3. Lotus

  4. Mango
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lotus have stomata on the upper surface of its leaves. Hence, Coating of Vaseline on its upper surface will hinder transpiration. 

Mango is a terrestrial plant which has stomata in the lower surface of leaves. Hence transpiration will not be affected in mango because of coating Vaseline on the upper surface.
So, the correct answer is lotus.

Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

Which of the following reveals the role of air in the growth of green plants?

  1. Joseph Priestley

  2. Jan Ingenhousz

  3. T. W. Engelman

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Joseph Priestley conducted experiments in 1774 showing that plants restore the air that has been 'injured' by burning candles or breathing animals, demonstrating the role of plants in gas exchange.

Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

Van Helmont concluded that plants get their food from

  1. Air

  2. Water

  3. Humus
  4. Air and ${H _2 O}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Van Helmont concluded that plants get their food from water. Van Helmont wanted to prove plants use materials from the soil to perform photosynthesis and done an experiment and proved that.

Multiple choice botany the leaf mechanism of absorption mineral absorption significance of transpiration

Choose the correct answers from the alternatives given.
One important difference between the anatomy and physiology of roots and leaves is that

  1. Unlike roots, the xylem vessels in leaves normally transport sap in both directions

  2. A waxy cuticle covers most leaves but is absent in roots

  3. Leaves, but not roots, have ground tissue consisting mainly of parenchyma cells

  4. Phloem always conducts sap away from leaves and toward roots
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The leaves are covered with waxy cuticle but roots do not possess any cuticle. Cuticle helps in preventing loss of water from the surface of the leaves. Since roots are present underground immersed in the soil they do not show transpiration and hence no cuticle is present. 

Hence, the correct answer is 'A waxy cuticle covers most leaves but is absent in roots'.

Multiple choice biology the leaf mechanism of absorption mineral absorption significance of transpiration

Meaningful girdling (ringing) experiment cannot be done on sugarcane because

  1. Phloem is present inside the xylem.

  2. It can not tolerate the injury.

  3. Vascular bundles are scattered.

  4. Plants are very delicate.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Monocots have scattered vascular bundles, while dicots have a continuous ring arrangement of vascular bundles. In a dicot stem, after a few years of growth, phloem is present as a single continuous layer or sheet on the outer side as a constituent of bark. 
  • It can be easily removed because it is present as a continuous sheet. In a similar manner phloem cannot be removed in a monocot stem, because of the scattered arrangement, some of the vascular bundles might be present near the surface and some embedded deep inside. 
  • Removing phloem from each of the bundles individually is not possible. The girdling experiment is used to identify the tissue through which food is conducted. In this experiment, a ring of phloem is removed from the woody plant. 
  • Hence girdling experiments cannot be performed on a monocot stem-like sugarcane.
Multiple choice biology fruit and seed morphology of the fruit fruit plants: structure and function

The ripening of fruits can be accelerated by 

  1. Reducing the supply of water to plant when fruits are maturing

  2. Increasing the supply of nitrogen to the atmosphere surrounding them

  3. Warming up the surroundings artificially

  4. Artificially adding ethylene gas to the atmosphere surrounding them
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ethylene is unique in that it found only in gaseous form, and accelerates ripening of fruits, leaves abscission and promotes senescence.

Multiple choice evs modern agriculture agricultural practices in india different types of farming and agriculture various agricultural practices

Which of the following ill effect is sorted out by the rooftop gardening?

  1. Insolation

  2. Photorespiration

  3. Ozone depletion

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The primary cause of heat buildup in cities is insolation i.e. absorption of solar radiation by roads and buildings. Storage of this heat by building material results in subsequent re-radiation. Due to transpiration of plant surface, its temperature does not rise 4-5 degree above the ambient and sometimes is cooler. This then translates into the cooling of the environment. Hence rooftop gardening reduces the overall heat absorption of the building which then reduces energy consumption. Thus the correct answer is option A.

Multiple choice evs - i flow of water irrigation irrigation and its types irrigation and types

In drip irrigation system water is irrigated drop by drop directly at the ____ of the crop through drippers set in small plastic tubes

  1. Root system

  2. Shoot system

  3. Leaf system

  4. Venation system
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Drip irrigation is designed to deliver water directly to the root zone of plants, minimizing evaporation and runoff.

Multiple choice biology transport in plants transport of food, water and minerals theories of translocation transport in the phloem of plants

Which hypothesis states that root absorbs a large quantity of ions along with absorption of water due to transpiration?

  1. Donnan equilibrium hypothesis

  2. Ion exchange hypothesis

  3. Mass flow hypothesis

  4. Kranz's hypothesis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Pressure flow hypothesis often regarded as mass flow hypothesis explains best about the movement of Plant sap through phloem .The concept was proposed by E.Munch . The transpiration of water from leaves and other part of plant body produces negative pressure inside transport vessels causing root to absorb large amount of water along with ions to maintain the continuity of column of water . 

So, correct Option is Option C.

Multiple choice biology transport in plants transport of food, water and minerals theories of translocation transport in the phloem of plants

Plants absorb minerals salts from the soil solution through

  1. A semipermeable membrane into the cytoplasm

  2. Perforations at the apex of root hair cells

  3. The cell wall which is semipermeable

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The mineral salts are absorbed into the symplasm, i.e., cytoplasm of root cells. There are special specific mineral transporters present in the plasma membrane of cells, which absorb the minerals from soil solution by transporting them across the membrane from soil solution to the cytoplasm of root cells. This way minerals can be absorbed irrespective of or against the concentration gradient of minerals. The minerals are present in the soil solution at very low concentrations and are usually absorbed against the concentration gradient with the help of specific carriers.

Multiple choice biology transport in plants transport of food, water and minerals theories of translocation transport in the phloem of plants

During respiration in plant root, carbonic acid is formed in the

  1. Root cells.

  2. Intercellular space.

  3. Soil.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Soil respiration refers to the production of carbon dioxide when soil organisms respire. They include roots and other microbiota. Roots continuously respire and liberate significant quantities of CO2. The CO2, when dissolved in soil water, produces carbonic acid.  Immediately they ionize into H+ and bicarbonate ions. Thus during respiration in plant root carbonic acid is formed. Thus the correct answer is option C.

Multiple choice biology transport in plants transport of food, water and minerals theories of translocation transport in the phloem of plants

The ions are .......... absorbed to the surface of root cells.

  1. Electrostatically

  2. Electromagnetically

  3. Osmotically

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Plant root cells contain relatively large quantities of organic cations and anions that do not diffuse through cell membranes. These organic ions could act as non-diffusible ions and may bind inorganic ions by electrostatic attraction. Thus ions are absorbed to the surface of roots electrostatically.

Thus, the correct answer is option A.

Multiple choice biology transport in plants transport of food, water and minerals theories of translocation transport in the phloem of plants

Contact exchange of ions occurs.

  1. Between root and soil particles

  2. Root and coil solution

  3. Cell and external solution

  4. All the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The contact exchange theory posits that ions adsorbed on the surface of soil particles are exchanged directly with ions on the surface of root hairs through contact.

Multiple choice botany root - external morphology morphology of the root root system in plants root

Root hairs arise from .......... and increase the ........... for absorption.

  1. Cortex and surface area

  2. Epidermis and cambium

  3. Cortex and cambium

  4. Epidermis and surface area
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

From the region of maturation in roots, the epidermis develops a special unicellular hair like structure known as root hairs that help to increase the surface area of root to maximize the absorption of water and minerals.

So, the correct option is 'Epidermis and Surface area'.