Tag: biology

Questions Related to biology

When a student observed a stomatal epidermal peel under the microscope, it appeared pinkish red.
The stain used was :

biology caskets of life observation of cells observing cells cell as structural and functional unit

  1. Iodine

  2. Methyl orange

  3. Safranin

  4. Methylene blue

Show answer
Correct Option: C
Explanation:

Safranin stains epidermal peel of leaf pinkish red in colour. Safranin is a biological stain used in histology and cytology. Safranin is used as a counterstain in some staining protocols, colouring all cell nuclei red. It can also be used for the detection of cartilage, mucin and mast cell granules.

Hence C is the correct option.

How is a bacterial cell different from an onion peel cell?

biology caskets of life observation of cells observing cells cell as structural and functional unit

  1. Bacterial cell- prokaryote, onion peel cell- eukaryote

  2. Onion peel cell- prokaryote, bacterial cell- eukaryote

  3. Bacterial cell- contains membranous organelles, onion peel cell- no membranous organelle

  4. None of these

Show answer
Correct Option: A
Explanation:

Bacterial cells are primitive cells hence, called as prokaryotic cells. They do not possess membrane bound organelles as mitochondria, lysosomes, etc. They also do not have well-defined membrane bound nucleus. 
Onion peel cell is an eukaryotic cell with well-defined membrane bound nucleus, membrane bound organelles as mitochondria, vacuole, etc. 

Temporary mount of a peel is made in :

biology caskets of life observation of cells observing cells cell as structural and functional unit

  1. Alcohol

  2. Water

  3. Glycerine

  4. Acetone

Show answer
Correct Option: C
Explanation:
Temporary mount of a leaf peel is used to observe stomata. Stomata are small openings found widely scattered on the epidermis of leaves and young stems.
Glycerine is a dehydrating agent. Once glycerine is added it forms a protective layer that keeps it moistened. It avoids the drying of the specimen. If staining is done after adding glycerine then the specimen will not be stained properly because the stain will be washed off with glycerine.
Hence C is the option. 

Temporary mount of a peel is made in :

biology caskets of life observation of cells observing cells cell as structural and functional unit

  1. Alcohol

  2. Water

  3. Glycerine

  4. Acetone

Show answer
Correct Option: C
Explanation:
Temporary mount of a leaf peel is used to observe stomata. Stomata are small openings found widely scattered on the epidermis of leaves and young stems.
Glycerine is a dehydrating agent. Once glycerine is added it forms a protective layer that keeps it moistened. It avoids the drying of the specimen. If staining is done after adding glycerine then the specimen will not be stained properly because the stain will be washed off with glycerine.

A well stained leaf peel preparation when focussed under high power of the microscope would
show :

biology caskets of life observation of cells observing cells cell as structural and functional unit

  1. epidermal cells, stomata and guard cells, each with one nucleus and many chloroplasts.

  2. epidermal cells, stomata and guard cells, each with many nuclei but one chloroplast.

  3. stomata and guard cells without nuclei or chloroplast.

  4. stomata but no guard cells or epidermal cells.

Show answer
Correct Option: A
Explanation:
A well-stained leaf peel shows nuclei in a high power microscope. The leaf peel possesses stomata, guard cells and epidermal cells. The nuclei are present in both epidermal and guard cells, but stomata do not possess any nucleus.
So A is the correct option. 

Given below are the steps in the preparation of a temporary mount of a stained leaf peel.
(i) Cover the material with the cover slip
(ii) Transfer the stained peel to a clean glass slide and add a drop of glycerine
(iii) Remove the peel from lower surface of leaf
(iv) Drop it in water in Petri dish and add a drop of  safranin stain.
The correct sequence of the experiment steps is

biology caskets of life observation of cells observing cells cell as structural and functional unit

  1. (a) (iii), (iv), (ii), (i)

  2. (b) (i), (ii), (iii), (iv)

  3. (c) (ii), (iii), (iv), (i)

  4. (d) (iii), (iv), (i), (ii)

Show answer
Correct Option: A

Which one of the following organisms is correctly matched with its three characteristics?

biology caskets of life observation of cells observing cells cell as structural and functional unit

  1. Onion: Bulb, Imbricate aestivation. Axile Placentation

  2. Maize, Closed vascular bundles, Scutellum

  3. Pea: $C _3$$ pathway, Endospermic, seed, Vexillary aestivation

  4. Tomato: Twisted aestivation, Axile placentation Berry

Show answer
Correct Option: A
Explanation:
Onion belongs to the family Liliaceae. It is a modified stem which is present in the underground, called bulb. It shows imbricate aestivation in perianth. The gynoecium is in axile placentation. The above characteristics are matched with the characteristics of onion. 

Hence, the correct answer is option A.

To distinguish microscopically between cheek cell and onion cell mount, one should look for the presence or absence of 

biology caskets of life observation of cells observing cells cell as structural and functional unit

  1. Mitochondria

  2. Plastids

  3. Cell membrane

  4. Nucleus

Show answer
Correct Option: B
Explanation:

Plastids are double membrane bound organelles found inside plants and some algae, which are primarily responsible for activities related to making and storing food. Many plastids are photosynthetic but some are not.

Therefore, to differentiate between a plant and an animal cell under a microscope, one must look for the presence of plastids.

Geeta was asked to prepare a temporary mount of onion peel and list the steps. While writing, she wrote the following steps, which may not be in proper sequence. The correct sequence would be
(i)   Add a few drops of safranin stain and transfer to a slide.
(ii)  Cover it with a coverslip.
(iii) Add a drop of glycerine.
(iv) Take out onion peel.
(v)  Keep the peel in water in a petri dish.

biology caskets of life observation of cells observing cells cell as structural and functional unit

  1. i, ii, iii, iv, v

  2. iv, v, iii, ii, i

  3. iv, v, i, iii, ii

  4. v, iv, i, iii, ii

Show answer
Correct Option: C
Explanation:

Initially, onion peel has to be taken out.
Then, keep the onion peel in water in a petridish. This will remove the impurities sticked to onion peel. 
Then, add a few drops of safranine stain and transfer to a slide.
Then, add a drop of glycerine on onion peel. This step prevents the peel from drying out. 
Then, cover it with a cover slip for observing it under the microscope and to study the cell pattern. 

Why is glycerine used for preparing a temporary mount?

biology caskets of life observation of cells observing cells cell as structural and functional unit

  1. Glycerine is isotonic to the cell sap

  2. It avoids drying of the material

  3. Both A and B

  4. None of the above

Show answer
Correct Option: C
Explanation:

Glycerine is isotonic to the cell sap. Due to this, cells used for mount will not shrink or swell and can be seen in their natural form. Also, glycerine makes the mounted material moist and prevents it from drying out.