Biology · Science General

Cell Biology and Structure

3,062 Questions

Cell biology focuses on the structure and function of cellular organelles. Key topics include cellular respiration, DNA inheritance, and energy production. These fundamental biology concepts are crucial for medical entrance and state service examinations.

Cell organelles functionsCellular respiration sitesDNA and ribosomesAnimal cell structurePlant cell components

Cell Biology and Structure Questions

Multiple choice zoology locomotion and reproduction flagella other cell components single membrane bound organelles

Which of the following statements regarding cilia is not correct?

  1. Cilia contain an outer of nine doublet microtubules surrounding two single microtubules.
  2. The organized beating of cilia is controlled by fluxes of Ca$^{2+}$ across the membrane.

  3. Cilia are hair-like cellular appendages.

  4. Microtubules of cilia are composed of tubulin.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cilium is an organelle found in eukaryotic cells and are hair-like appendages. Inside cilia, is a microtubule-based cytoskeleton called the axoneme. The axoneme of cilia has a ring of nine outer microtubule doublets and two central microtubule singlets in addition to the nine outer doublets, called 9+2 axoneme.
The organized beating of cilia, however, are produced by controlled sliding of outer doublet microtubules.

Multiple choice zoology locomotion and reproduction flagella other cell components single membrane bound organelles

9 + 0 arrangement is found in

  1. Flagellum

  2. Centriole

  3. Cilium

  4. Spindle fibres
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Centriole- The centrosome is made up of 2 centrioles which are right angled to each other and is composed of a protein known as tubulin.
  • It produces spindle apparatus at the time of cell division.
  • Each centriole has 9 peripheral groups of microtubules (triplet) with no central microtubules thus, this type of arrangement in centriole is called 9+0 pattern.
  • So, the correct answer is 'Centriole'.
Multiple choice zoology locomotion and reproduction flagella other cell components single membrane bound organelles

Axoneme with 9+2 microtubular arrangement occurs in

  1. Cilia

  2. Flagella

  3. Both A and B

  4. Centriole
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Axoneme with 9+2 microtubular arrangement occurs in both cilia and flagella.
  • Cilia and flagella are cellular projections which are covered by an extension of the plasma membrane. 
  • They both have similar internal structures and are made up of microtubules.
  • The microtubule arrangement within cilia and flagella is 9 + 2 arrangement of microtubules.
  • It contains nine fused pairs of microtubules on the outer side of a cylinder and the two unfused microtubules at the centre.
  • So, the correct answer is 'Both A and B'.
Multiple choice zoology locomotion and reproduction flagella other cell components single membrane bound organelles

Tubulin occurs in

  1. Microtubules

  2. Cilia and flagella

  3. Microvilli

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

Tubulin belongs to the protein superfamily of globular proteins.Alpha and beta tubulins polymerize into microtubules. Microtubules function in many processes like structural support, intracellular transport, and DNA segregation. Microtubules emerge from microtubule organizing center in eukaryotic cells.

Cilia and flagella contain the motor protein dynein and microtubules, in the form of two central and nine doublets surrounding it.Cilia and flagella help in locomotion in unicellular eukaryotes.
Microvilli are cellular membrane protrusions that increase the surface area for diffusion.
Therefore option D is correct.

Multiple choice zoology locomotion and reproduction flagella other cell components single membrane bound organelles

Axoneme is a structure associated with

  1. Golgi bodies

  2. Only cilia

  3. Only flagella

  4. Both cilia and flagella
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Axoneme is the central strand of a cilium or flagellum. It is composed of an array of microtubules, typically in nine pairs around two single central ones.Cilia and flagella is made of the axoneme which is composed of microtubules and their associated proteins.

So, the correct answer is 'D'.
Multiple choice zoology locomotion and reproduction flagella other cell components single membrane bound organelles

The movement of the flagellum is regulated by 

  1. Plasma membrane

  2. Nucleus

  3. Basal body

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

Bacterial flagella are helically shaped structures containing the protein flagellin. The base of the flagellum (the hook) near the cell surface is attached to the basal body enclosed in the cell envelope. The flagellum rotates in a clockwise or counterclockwise direction, in a motion similar to that of a propeller. This movement is regultaed by plasma membrane.

Thus, the correct answer is 'Plasma membrane.'

Multiple choice zoology locomotion and reproduction flagella other cell components single membrane bound organelles

Filaments present in flagella/cilia are

  1. Microfibrils

  2. Microtubules

  3. Microfilaments

  4. Microvilli
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Cilia and flagella are small hair-like projections from the cell and are composed of microtubules which are arranged with their positive end at the outer tip of the axoneme.
  • A microtubule is a tubular linear polymer of tubulin protein which is a part of the cytoskeleton that helps to provide structure and shape to the cytoplasm of a eukaryotic cell.
  • So, the correct answer is 'Microtubules'.
Multiple choice biology transport in plant transport in the phloem of plants vascular tissue permanent tissue

Which of the following statement is true?

  1. Vessels are multicellular with wide lumen.

  2. Tracheids are multicellular with narrow lumen.

  3. Vessels are unicellular with narrow lumen.

  4. Trachieds are unicellular with wide lumen.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Vessels are multicellular with wide lumen. They are made up of vessel  elements lying one above the other. The wall of vessels is hard but not thick having wide lumen. Whereas tracheids are unicellular with narrow lumen. 

Thus, the correct answer is 'Vessels are multicellular with wide lumen'.

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of dicot leaf internal structure of leaf (dicot and monocot)

Largest number of chloroplasts are found in

  1. Palisade tissue

  2. Spongy tissue

  3. Transfusion tissue

  4. Bundle sheath cell
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Palisade cells contain the largest number of chloroplasts per cell, which makes them the primary site of photosynthesis in the leaves of those plants that contain them, converting the energy in light to the chemical energy of carbohydrates. Beneath the palisade mesophyll are the spongy mesophyll cells, which also perform photosynthesis. Spongy cells acts well in high intensity light.

Multiple choice zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

Colloblast (adhesive) cells are the characteristic of 

  1. Hydra

  2. Comb jelly

  3. Obelia

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Tentacles are the organs which are used to catch the prey. These are present at the opening of the gastrovascular cavity. Colloblasts are a cell type found in ctenophores. They are widespread in the tentacles of these animals and are used to capture prey. These are found in all ctenophores except those of the order Beroida, as they lack tentacles. So, the correct answer is option B.

Multiple choice zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

Which is absent in ctenophores?

  1. Epidermis

  2. Intercellular and intracellular digestion

  3. Cnidoblasts

  4. Medusa phase.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ctenophores have colloblast in their tentacles to capture/ disarm their prey as opposed to cnidarians like jelly fish having Cnidoblasts doing the same function.

So, the correct answer is 'Cnidoblasts'.

Multiple choice zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

What is present in mesoglea of ctenophores which makes it a loose layer of cells?

  1. Amoebocytes

  2. Elastic cells

  3. Nerve cells and muscle cells

  4. All the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The loose layer of jelly-like substance in Ctenophores is mesoglea which are composed of muscle bundles and nerve fibres that lie under the epethelial cells. They are hydrostatic and have elastic cells along with amoebocytes that have a role in phagocytosis, 

So, the correct answer is 'All the above'.

Multiple choice biology the flower structure of a bisexual flower growth and development in plants basics of leaf and flower

A nectar-secreting gland cell characteristically contains

  1. Granular cytoplasm filling the cell and a small nucleus.

  2. Granular cytoplasm living a central vacuole and a small nucleus.

  3. Granular cytoplasm filling the cell and a large conspicuous nucleus.

  4. Vacuolated cytoplasm but with a large nucleus.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Nectaries are the excretory glands (that exude their secretion and do not store it) which are characterized by presence of rich granular cytoplasm in protoplast and conspicuous nucleus.
They lack vacuoles which makes. Large vacuole with inconspicuous cytoplasm and small nucleus are characteristic features of secretory cells that store their secretions. 
Therefore, the correct answer is option C.

Multiple choice botany caskets of life the cell structure multicellular organisms number and shape of cells
Different cells have different sizes. Arrange the following cells in an ascending order of their size and select the correct option.
(i) Mycoplasma (ii) Ostrich egg (iii) Human RBCs (iv) Bacteria.
  1. $(i)\rightarrow (iv)\rightarrow (iii) \rightarrow (ii)$
  2. $(ii)\rightarrow (iii)\rightarrow (i) \rightarrow (ii)$
  3. $(ii)\rightarrow (i)\rightarrow (iii) \rightarrow (iv)$
  4. $(iii)\rightarrow (ii)\rightarrow (i) \rightarrow (iv)$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The size order is: Mycoplasma (smallest, ~0.1-0.3 micrometers) < Bacteria (~1-2 micrometers) < Human RBCs (~7-8 micrometers) < Ostrich egg (largest, macroscopic).