Cell Biology Quiz-14

Cell Biology Quiz-14

Dear Readers,

NEET is the most famous and important medical entrance examination held in our country. This exam is an objective type, an offline test which includes 4 sections namely– Physics, Chemistry, Botany, and Zoology. The maximum marks that can be scored are 720 marks and have 180 questions. About half of the paper consists of questions from Biology, as the NEET exam essentially focuses on capacitating students to go for seats in medical courses. One of the most significant and crucial sections in the NEET exam is of Biology. It comprises of theories, descriptions, discoveries, diagrams, definitions, explanations of differences, and relations. The majority of the topics covered in the NEET syllabus are from the NCERT syllabus of Class 11 & 12 and other related sources become part of the rest of the syllabus. Clear Exam curates a list of articles selected by professionals who recommend the highly vital topics for NEET exams. The table below takes you directly to the respective topic where the in-depth article and the MCQs are available for an easy and productive learning experience. Prior to solving NEET question papers or practicing mock tests, you must ensure to study the basic concepts in NEET and practice a few sample questions related to this exam. Students will be covered for all their studies as the topics are available from basics to even the most advanced. .

Q1.   Solenoid is a structure of

•  Nucleosomal organisation with 10nm thickness
•  Condensed chromatin fibre with 30nm diameter
•  Highly condensed form of chromatid with 300 nm thickness
•  Well organised chromatid with 700 nm thickness

Solution
(b) Solenoid Model (the supra-nucleosomal structure) explains how the nucleosomes are packed into the 200-300 Å thick nucleofilament of chromatin. Finch and Klug (1976) found a close packing of nucleosomes to produce a nucleofilament, a fibre 100Å in diameter. The nucleofilaments (chromatin fibre) is further coiled up to a form of solenoid with a diameter of 300-350Å (30 nm). There are about six nucleosomes per turn of the solenoid coils.

Q2.   What is the difference between RNA and DNA?

•  Base
•  Sugar
•  Both (a) and (b)
•  Phosphate

Solution
(a) DNA has deoxyribose pentose sugar and four nitrogenous bases, i.e., adenine (A), guanine (G), both purines and cytosine(C), thymine (T) both pyrimidines. While, RNA has ribose pentose sugar and four nitrogenous bases as in DNA except uracil (U) in place of thymine.

Q3.   Which statement is not true about prokaryotes?

•  DNA is completed with histones
•  Well-developed nucleus is absent
•  Mesosome is present
•  Mitochondria is absent

Solution
(a) In prokaryotic cells, the genetic material is not organised into nucleus and all the membrane bound organelles are absent. The histone proteins are absent and therefore, the genetic material is not organised into chromatin

Q4.   Which is not true about spherosomes?

•  Arise from ER
•  Related to fat
•  Single membrane bound structure
•  Involved in photorespiration

Solution
(d) Spherosomes are not involved in photorespiration.

Q5.   A conspicuous rounded body present in nucleoplasm and attached to a particular chromosome at a definite place is

•  Plasmid
•  Karyolymph
•  Nucleolus
•  Nuclear reticulum

Solution
  (c) Nucleolus is present is nucleoplasm and attached to a particular chromosome at particular place.

Q6.   In prokaryotic cells, which enzyme erases primer and fill gaps in DNA

•   Helicase
•  Primase
•  DNA polymerase-II
•  DNA polymerase-I

Solution
(d) (a) Helicase Unwinds the double helix (b) DNA polymerase-I Erases primer and fill gaps (c) DNA polymerase-II Synthesises DNA (d) Primase Synthesises RNA primers

Q7.   Vacuoles are separated from cytoplasm by a membrane called

•  Protoplast
•  Cytoplasm
•  Chloroplast
•  Tonoplast

Solution
(d) Vacuoles are separated from cytoplasm by a membrane called tonoplast

Q8.   Which of the character is not applicable to tRNA?

•  It is the smallest of the RNAs
•  It acts as an adaptor for amino acid
•  It has a clover leaf like structure
•  It is the largest of the RNAs

Solution
(d) Transfer RNA (tRNA) or soluble RNA (sRNA) is the smallest (4S) which constitutes about 15% of the total. tRNA is also called adapter molecule because it helps in transferring amoni acids to ribosomal sites during polypeptide synthesis.

Q9.   Which of the following statements are correct about prokaryotic cells? I. DNA lies freely in the cytoplasm, not associated with any organelle II. The amount of DNA do not change as there are no haploid and diploid stages III. Transcription and translation occurs in the cytoplasm IV. Protein synthesis occurs only in the cytoplasm Correct option regarding the above statement is

•  I, II and III
•  I and II
•  Only I
•  I, II, III and IV

Solution
(d) In a prokaryotic cell, DNA lies freely in the cytoplasm, not associated with any organelle The amount of DNA remains unchanged as there are no haploid or diploid stages. Transcription and translation occurs in the cytoplasm. Protein synthesis occurs only in cytoplasm

Q10.   For the study of structure of nucleus, the best cell is

•  Cell in the interphase
•  Cell in the late prophase
•  Cell in the divisional phase
•  Cell in the meiotic phase

Solution
(a) Nucleolus is the site of ribosomal RNA synthesis. During interphase, nucleus contains loose and indistinct network of nucleoprotein fibres called chromatin