Tag: structure of a plant cell

Questions Related to structure of a plant cell

The plant cells wall in a cross-section appears to be made up of many layers due to the.

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

  1. Presence of large amount of cellulose in the wall

  2. Presence of lignin which prevents the folding cellulose micro fibrils

  3. Presence of different composition and structure of the lamellae which are added continuously as the wall grows

  4. Orientation of micro fibrils in the different lamellose of the wall that result in differences in the refraction of light so that layers of the wall are emphasized

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Correct Option: A

Choose the correct answers from the alternatives given.
When a plant cell is placed in pure water, it will

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

  1. Become rigid because of turgor pressure

  2. Lose water and wilt

  3. Swell and burst

  4. Alter its cell wall composition so that it becomes impermeable to water

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Correct Option: A
Explanation:

Pure water is a hypotonic solution that causes endosmosis. The water diffuses into the cell causing the cytoplasm to build up pressure against the wall. This pressure is called turgor pressure that causes rigidity of the cell and the cell does not burst. This turgor pressure is responsible for the enlargement and extension of the cells during growth.

Hence, the correct answer is 'Become rigid because of turgor pressure'.

Select the wrong statement with respect to the structure of a plant cell.

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

  1. Cellulosic cell wall is present inside the cell membrane

  2. Centrioles are usually absent

  3. A large central vacuole is present

  4. Golgi apparatus is formed of a number of unconnected units called dictyosomes

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Correct Option: A
Explanation:

Cell wall is the outer rigid protective and supportive covering of plant cells, fungi and some protists. Cell membrane is covering of protoplasm which occurs inside the cell wall. In plants the cell wall is made of cellulose.

So, the correct answer is 'Cellulosic cell wall is present inside the cell membrane'

Angiotensinogen is a protein produced and secreted by ________________.

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

  1. Juxtaglomerular (JG) cells

  2. Macula densa cells

  3. Endothelial cells (cells lining the blood vessels)

  4. Liver cells

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Correct Option: D
Explanation:

Angiotensinogen is a αα - globulin protein produced by liver cells. Renin changes angiotensinogen to angiotensin II (hormone) in response to fall in glomerular blood flow/glomerular blood pressure/GFR. Angiotensin II increases blood pressure and blood volume. 

With which of the following are basal bodies not associated?

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

  1. Plant cells

  2. Animal cells

  3. Centrioles

  4. Microtubules

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Correct Option: A
Explanation:

Basal body is also known as kinetosome. This is a short cylinder like a centriole, consists of nine triplet microtubules; it organizes assembly of the axoneme microtubules.
Animal cells posses centrioles and basal bodies, which are involved in cell division. 
Centrioles are cylindrical organelles that help in cell division. Basal bodies are formed from centrioles. 
Microtubules are filamentous structures formed from centrioles, which are involved in chromosomal separation during cell division. Nine triplets microtubules together form basal body. 
Plant cells do not possess centriole. Hence, it does not possess basal bodies formed from centrioles. 

What is the innermost portion of a mature plant cell wall called as?

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

  1. Primary cell wall

  2. Secondary cell wall

  3. Lamella

  4. Tonoplast

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Correct Option: B
Explanation:
Cell wall consists of three layers: the primary cell wall, secondary cell wall and the middle lamella.
The middle lamella- It is the first layer formed during cell division. This layer is rich in pectin. It is the outermost layer, joins together adjacent plant cells and holds them together.
The primary cell wall- It is formed after the middle lamella. It is composed of pectin compounds, hemicellulose and glycoproteins. The layer consists of a framework of cellulose microfibrils, in a gel-like matrix. It is a thin, flexible and extensible layer.
The secondary cell wall- It is a thick layer formed inside the primary cell wall. It is extremely rigid and provides strength. It is composed of cellulose, hemicellulose and lignin.

Why do plant cells possess large sized vacuole?

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

  1. Storage

  2. Dumping of cellular wastes

  3. Maintaining turgidity in a cell

  4. All of the above

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Correct Option: D
Explanation:

Vacuoles are like storage bubbles which are found mostly in plant cells. They occupy most of the portion of plant cells. These are used for storage of food or water. They also store toxic metabolic by-products or end products of plant cells. Such vacuoles are thrown out of the cell by exocytosis. Osmotic pressure and turgidity are maintained by vacuoles due to the presence of cell sap. 

The plant cell lacks 

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

  1. Centriole and aster

  2. Asters

  3. Centriole

  4. Microtubules

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Correct Option: A
Explanation:

Centrosomes are the cellular organelles which are involved in the formation of centrioles. The centrioles are the centres for the formation of the microtubules required for the spindle fibres formation during cell division. The aster is the star-like formation around the centriole. This is the region from where the spindle fibres get distributed in all the sides. The centrioles and aster are present in the animal cells and absent in the plant cells. Thus, the correct answer is option A. 

The cellulosic cell wall is essential for plant cell because 
(a) It gives shape to the cell.
(b) It gives protection to the cells.
(c) It is able to withstand high temperature, high wind speed and atmospheric moisture.
(d) It is involved in the recognition of substances required for the cells.

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

  1. a, b, and d

  2. a, c and d

  3. b, c and d

  4. a, b and c

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Correct Option: D