Tag: structural organization in living organisms

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Questions Related to structural organization in living organisms

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

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

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
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'.
Multiple choice biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

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

  1. T.P. $-$ D. P.D.
  2. D. P. D. $-$ T.P.
  3. T.P. $-$ D.P.
  4. D. P.D. $+$ T.P.
Reveal answer Fill a bubble to check yourself
D Correct answer
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. 
Multiple choice biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

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

  1. Prokaryotic

  2. Protozoan cells

  3. Hygrophytic plant cells

  4. Xerophytic plant cells
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

The percentage of water in a typical plant cell is about 

  1. 10%

  2. 20%

  3. 50%

  4. 80%
Reveal answer Fill a bubble to check yourself
D Correct answer
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. 

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

The secretory cells of the plants are

  1. <font color="#000000">Nectary cells</font>

  2. Hydathode

  3. Laticifer cells

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
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.
Multiple choice biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

Most abundant element in plant body is 

  1. Potassium

  2. Nitrogen

  3. Carbon

  4. Hydrogen
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

Growth of cell wall during cell elongation takes place by 

  1. Apposition

  2. Intussusception

  3. Both A and B

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

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

Cell wall of plant cells is formed of 

  1. Cellulose

  2. Hemicellulose

  3. Proteins

  4. Fats
Reveal answer Fill a bubble to check yourself
A Correct answer
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. 

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

Which of the following is the characteristic of plants ________________.

  1. Glucose and cellulose

  2. Pyruvic acid and glucose

  3. Cellulose and starch

  4. Starch and pyruvic acid
Reveal answer Fill a bubble to check yourself
C Correct answer
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.