Tag: botany

Quizzes (264) Questions (5276)

Questions Related to botany

Multiple choice botany cell theory, cell specialization, and cell replacement number and shape of cells unicellular and multicellular organisms diversity and classification in animals

Forthe formation of diploid cells from haploid cells, colchicine is used to

  1. Stop the spindle fibres formation

  2. Replicate DNA twicely in one cell cycle

  3. Stop the formation of centromere

  4. Stop the mitotic division
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Colchicine is an alkaloid that inhibits microtubule polymerization by binding to tubulin. This prevents the formation of spindle fibers during mitosis, leading to polyploidy.

Multiple choice botany cell theory, cell specialization, and cell replacement number and shape of cells unicellular and multicellular organisms diversity and classification in animals

Growth at cellular level, is principally a consequence of increase in the amount of

  1. Protoplasm

  2. DNA

  3. Cell wall

  4. Cell organelles
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Protoplasm comprises of cytoplasm, nucleus and other cell organelles. Growth at cellular level includes increase in size of nucleus and other cell organelles. The growth at cellular level is a result of increase in amount of protoplasm.

Thus, the correct answer is 'Protoplasm.'

Multiple choice botany cell theory, cell specialization, and cell replacement number and shape of cells unicellular and multicellular organisms diversity and classification in animals

Which of the following factors affect a cell's surface area to volume ratio?
(I) Cell size
(II) Presence of selectively permeable membrane
(III) Presence of a convoluted membrane
(IV) Presence of many membrane transport protein

  1. (I) only

  2. (I), (II), (III) only

  3. (I) and (III) only

  4. (III) and (IV) only
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The surface area to volume ratio is primarily determined by the physical dimensions (size) of the cell. While membrane structure affects transport efficiency, the geometric ratio itself is a function of the cell's size and shape.

Multiple choice botany cell theory, cell specialization, and cell replacement number and shape of cells unicellular and multicellular organisms diversity and classification in animals

Refer to the following table for your possible answer.

Cell types analysed Average mass of DNA/cell (x $10^{-11}$g)
X $0.00$
Y $3.35$
Kidney $6.70$
Lung $6.70$

What is the correct identify of cell type X and Y?

  1. X-sperm cell, Y-liver cell

  2. X-liver cell, Y-smooth muscle cell

  3. X-smooth muscle cell, Y-mature red blood cell

  4. X-mature red blood cell, Y-sperm cell
Reveal answer Fill a bubble to check yourself
D Correct answer
Multiple choice botany cell theory, cell specialization, and cell replacement number and shape of cells unicellular and multicellular organisms diversity and classification in animals

The maximum work that a standard Daniell cell can do before it stops working is
$[1 \,F = 96487\, C\, mol^{-1}\, and\, E^o = 1.1 V]$

  1. $212.271\, kJ \,mol^{-1}$
  2. $21.227\, kJ \,mol^{-1}$
  3. $721.221 \,kJ \,mol^{-1}$
  4. $71.222 \,kJ \,mol^{-1}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The maximum work (Gibbs free energy change) is calculated as W = nFE. For a Daniell cell, n=2. W = 2 * 96487 * 1.1 = 212271.4 J/mol, which is 212.271 kJ/mol.

Multiple choice botany cell theory, cell specialization, and cell replacement number and shape of cells unicellular and multicellular organisms diversity and classification in animals

The surface area to volume ratio increase as the cell size 

  1. Unaltered

  2. Slightly increase

  3. Decrease

  4. Increase in many layers
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The total area on the surface of an object is called as 'Surface area' and here the object is 'cell'. While the volume is the amount of the space present inside the cell.

The volume is expressed in cubic units while surface area is expressed in square units
The surface area and volume gets affected, when size of the cell is altered i.e., either increased or decreased.
Let's see how the surface area and volume ratio gets affected...

  • When the cell size increases, the volume increases more than surface area because the volume increases in cubes while surface area increases in squares. Hence, both volume and surface area increases at different rates. And here the surface area to volume ratio decreases as the volume is more than surface area.
  • When the cell size decreases, the volume decreases at unequal rates with respect to surface area. This leads to an increase of the surface area to volume ratio.
Therefore, the surface area to volume ratio increases with the decrease in cell size.

Multiple choice botany cell theory, cell specialization, and cell replacement number and shape of cells unicellular and multicellular organisms diversity and classification in animals

Smaller cells have

  1. Small surface area per volume ratio.

  2. Large surface area per volume ratio.

  3. Slow exchange rate of nutrients.

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

Surface area to the volume ratio gets smaller as the cell gets larger. Thus, if the cell grows beyond a certain limit, not enough material will be able to cross the membrane fast enough to accommodate the increased cellular volume. Small cells, therefore, have a large surface area to volume ratio. The large surface area to volume ratio of small cells makes the transport of substances into and out of cells extremely efficient.

Multiple choice botany cell theory, cell specialization, and cell replacement number and shape of cells unicellular and multicellular organisms diversity and classification in animals

Large cells have a

  1. High metabolic rate.

  2. High respiration rate.

  3. Low surface: volume ratio.

  4. High surface: volume ratio.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

As a cell increases in size, its volume increases much faster than its surface area. This results in a decrease in the surface area to volume ratio, which limits the efficiency of nutrient and waste exchange.

Multiple choice botany cell theory, cell specialization, and cell replacement number and shape of cells unicellular and multicellular organisms diversity and classification in animals

When a cell of $2\mu$$m$ diameter grows to double its diameter, its surface area: volume relationship will _____________.

  1. Remain the same.

  2. Become double.

  3. Reduce to half.

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

Surface area (SA) is proportional to r^2 and volume (V) to r^3. The ratio SA/V is proportional to 1/r. If the diameter (and thus radius) doubles, the ratio becomes 1/2 of the original.

Multiple choice botany cell theory, cell specialization, and cell replacement number and shape of cells unicellular and multicellular organisms diversity and classification in animals

Metabolically active cells have

  1. Lower nucleocytoplasmic ratio.

  2. Higher nucleocytoplasmic ratio.

  3. Higher surface: volume ratio.

  4. Both B and C.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Metabolically active cells require efficient exchange (high surface area to volume ratio) and often have a large nucleus to manage cellular processes (higher nucleocytoplasmic ratio).