Tag: structural organization in living organisms

Questions Related to structural organization in living organisms

When a plant cell is placed in pure water, it?

biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

  1. Expands until the osmotic pressure reaches that of water

  2. Becomes less turgid until the osmotic potential reaches that of pure water

  3. Becomes more turgid until the pressure potential of cell reaches its osmotic potential

  4. Becomes more turgid until the osmotic potential reaches that of pure water

Show answer
Correct Option: C
Explanation:
Plant cells are enclosed by a rigid cell wall. When the plant cell is placed in a hypotonic solution, it takes up water by osmosis and starts to swell, but the cell wall prevents it from bursting. The plant cell is said to have become "turgid" i.e. swollen and hard. The pressure inside the cell rises until this internal pressure is equal to the pressure outside. This liquid or hydrostatic pressure called the turgor pressure prevents further net intake of water.
So the correct answer is 'becomes more turgid until the pressure potential of the cell reaches its osmotic potential'.

Draw well labelled diagram of the following

biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

  1. plant cell

  2. Animal cell

  3. prokaryotic cell

  4. Nerve cell

  5. striated and smooth muscles

Show answer
Correct Option: A

In a plant cell, O.P. is equal to?

biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

  1. T.P. $-$ D. P.D.

  2. D. P. D. $-$ T.P.

  3. T.P. $-$ D.P.

  4. D. P.D. $+$ T.P.

Show answer
Correct Option: D
Explanation:
When a plant cell is placed in hypotonic solution, water enters into a cell by osmosis and as a result turgor pressure develops. The cell membrane gets stretched and osmotic pressure of cell decreases. As cell absorbs more and more water its TP increases and OP decreases. When a cell is fully turgid, its OP is equal to TP and DPD is zero. The turgid cell cannot absorb any more water. Thus, with reference to a plant cell, the DPD can be described as actual thirst of the cell for water and can be expressed as DPD=OP-TP. When DPD is zero, entry of water will stop. Thus it is DPD that tends to equate and represents water absorbing ability of a cell, it is also called suction force (SF) or suction pressure (SP). 
Therefore, the correct answer is option D. 

The inclusion like raphides, druses and sphaeraphides can be mainly found in which of the following cells?

biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

  1. Prokaryotic

  2. Protozoan cells

  3. Hygrophytic plant cells

  4. Xerophytic plant cells

Show answer
Correct Option: D
Explanation:

Plant cells sometimes form mineral crystals. Calcium carbonate occurs as a mass of crystals around a cellulose core to form cystolith (eg, leaf of Banyan). In several plants, calcium oxalate forms needle-like raphides, prismatic crystals, star-shaped sphaeraphides or Druses or powdery mass named as crystal sand.

Xerophytes, in general, possess hypertonic cell sap and have higher mineral content which favours accumulation and formation of inorganic crystals.
Thus, the correct answer is option D.

The percentage of water in a typical plant cell is about 

biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

  1. 10%

  2. 20%

  3. 50%

  4. 80%

Show answer
Correct Option: D
Explanation:

Plants are made up of water, organic and inorganic substances. Water makes the majority of the volume of the plant cell. Water comprises of 80-90 percent of the plant's total weight. Water is used to support the cell structure, for metabolic functions, to carry the nutrients and for photosynthesis. 

The secretory cells of the plants are

biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

  1. Nectary cells

  2. Hydathode

  3. Laticifer cells

  4. All of the above

Show answer
Correct Option: D
Explanation:
Nectaries secrete sweet liquid to attract and feed pollinators.
A hydathode is a type of secretory tissue in leaves, usually found in Angiosperms and peridophytes, that secretes water through pores in the epidermis or margin of leaves, typically at the tip of a marginal tooth or serration.
A laticifer is a type of elongated secretory cell found in the leaves and/or stems of plants that produce latex and rubber as secondary metabolites.
Thus, the correct answer is option D.

Most abundant element in plant body is 

biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

  1. Potassium

  2. Nitrogen

  3. Carbon

  4. Hydrogen

Show answer
Correct Option: D
Explanation:

A most abundant compound in living organisms protoplasm is water. Plants contain even more water than animals do- most of them are anywhere from 90 to 95% water. In plants, about 85% of the fresh weight of leaves can be water. Each water molecule is made up of two hydrogen and one oxygen atom. Hence, hydrogen is the most abundant element in a plant body.

Growth of cell wall during cell elongation takes place by 

biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

  1. Apposition

  2. Intussusception

  3. Both A and B

  4. None of the above

Show answer
Correct Option: B
Explanation:

Plant cell is covered by a cellulosic cell wall. The cell wall is dead at maturity but grows when immature to permit cell elongation. Intussusception is growth by deposition of new materials between existing components of cell walls. Cell elongation occurs through intussusception. In apposition, new wall layers are laid. Growth of wall in new cells occurs through apposition.

Cell wall of plant cells is formed of 

biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

  1. Cellulose

  2. Hemicellulose

  3. Proteins

  4. Fats

Show answer
Correct Option: A
Explanation:

The cell wall is a protective outer covering of the cell. It is mostly present in plant cells. It is not present in the animal cell. It supports the contents of the cell and protects from pathogen attack and wear and tear. It is made of cellulose. Cellulose is a natural polymer made of smaller sugar units. It gives remarkable strength to the wood. 

Which of the following is the characteristic of plants ________________.

biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

  1. Glucose and cellulose

  2. Pyruvic acid and glucose

  3. Cellulose and starch

  4. Starch and pyruvic acid

Show answer
Correct Option: C
Explanation:

Cellulose is a structural polysaccharide found in the cell walls of plants.

Plant cell wall is required not only for the structure to determine the actual shape of cells and functional properties to control inner and outer cellular communication but also for overall growth and tree expansion. Cellulose is the most significant component of plant cell walls. 
Starch is an energy storage polysaccharide found in plants.Plants need energy to grow.They use energy from sunlight to make a simple sugar, glucose.Plants make polymers - starch - out of extra glucose,so it's right there when they need it.