Q21
The DNA present in chloroplast is:
Correct Answer
Option B
Solution
The DNA in chloroplasts is circular and double-stranded, similar to bacterial DNA.
This supports the endosymbiotic theory.
Cell: The Unit of Life
Q22
In tissue culture experiments, leaf mesophyll cells are put in a culture medium to form callus. This phenomenon may be called as
Correct Answer
Option A
Solution
In tissue culture experiments, leaf mesophyll cells are put in a culture medium to form callus.
This phenomenon may be called as dedifferentiation.
Dedifferentiation is a phenomenon by which the living differentiated plant cells, that by now have lost the capacity to divide can regain the capacity of division under certain conditions.
Q23
How many different proteins does the ribosome consist of?
Correct Answer
Option D
Solution
The ribosome consists of structural RNAs and about 80 different proteins.
Q24
Which of the following functions is carried out by cytoskeleton in a cell?
Correct Answer
Option B
Solution
An elaborate network of filamentous proteinaceous structures consisting of microtubules, microfilaments and intermediate filaments present in cytoplasm is collectively referred to as the cytoskeleton.
It is involved in many functions such as mechanical support, motility, maintenance of the shape of the cell.
Q25
Which type of substance would face difficulty to pass through the cell membrane?
Correct Answer
Option C
Solution
Substances that have a hydrophilic moiety find it difficult to pass through the plasma membrane; thus, their movement has to be facilitated.
Q26
If the pH in lysosomes is increased to alkaline, what will be the outcome?
Correct Answer
Option C
Solution
Lysosomes contain hydrolytic enzymes which become active at acidic pH.
If pH in lysosomes is increased to alkaline or basic then hydrolytic enzymes will become inactive.
Q27
Which of the following statements with respect to Endoplasmic Reticulum is incorrect?
Correct Answer
Option C
Solution
In prokaryotes, ER is absent be it RER or SER.
Q28
Which of the following is an incorrect statement?
Correct Answer
Option B
Solution
A mature sieve tube elements possess a peripheral cytoplasm and a large central vacuole but lacks a nucleus.
Rest of other statements are correct.
Q29
When the centromere is situated in the middle of two equal arms of chromosomes, the chromosome is referred as :
Correct Answer
Option B
Solution
When the centromere is situated in the middle of two equal arms of chromosomes, the chromosome is referred as Metacentric.
When the centromere is present slightly away from the middle, it is called sub-metacentric chromosome.
When the centromere is present very close to one end of the chromosome, it is called acrocentric chromosome.
When the centromere is present at terminal position, the chromosome is called telocentric.
Q30
The organelles that are included in the endomembrane system are
Correct Answer
Option C
Solution
Endomembrane system consist of endoplasmic reticulum, Golgi complex, vacuoles and lysosomes.
Mitochondria is semi-autonomous cell organelle.
Ribosome is non-membranous cell organelle.
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