Biology · Science General

Cell Biology and Structure

3,221 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

Basal body is associated with the development of

  1. Cilia and flagella

  2. Cell plate

  3. Phragmoplast

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

Basal bodies/ basal granules/ kinetosomes/ blepharoplasts are the micro-cylinders that lie below the plasmalemma at the base of flagella or cilia. Cilia and flagella are vibratile hair like narrow protoplasmic processes present on the free surface of the cell which are connected with motility. Each one is made up of four parts: basal body, rootlets, basal plate and shaft.

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. Microtubules of cilia are composed of tubulin.

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

  4. Cilia are hair-like cellular appendages.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The shaft of cilia and flagella consists of an external sheath, semi fluid matrix and an axoneme. Axoneme has 9+2 fibrillar arrangement, comprising of nine peripheral doublet microtubule fibrils and two central singlet microtubule fibrils, central sheath, linkers and spokes. Certain flagella possess lateral hairs called flimmer filaments. Such flagella are called tinsel Flagella.

Flagella devoid of flimmers are called smooth or whiplash flagella. The cilia function like an oar. They have a power or effective stroke which pushes the fluid in one direction with a jerk while the cell is pulled in the opposite direction. This movement does not depends on calcium ion flux.

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

Read the following statements and state true (T) or false (F) regarding cilia and flagella of eukaryotic cells.
The axoneme usually has nine pairs of triplets of radially arranged peripheral microtubules.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Axoneme refers to the cytoskeletal structure which forms the central strand of a cilium or a flagellum.
  • It is composed of an array of microtubules which typically consists of nine pairs of doublet around two single central ones.
So the correct answer is 'False'.
Multiple choice zoology locomotion and reproduction flagella other cell components single membrane bound organelles

ATP powers the movement of cilia and flagella in eukaryotic cell. These ATP molecules are hydrolysed into ADP+Ip in cilia and flagella by the activity

  1. Nexin protein

  2. Dynein protein

  3. Myosin of muscles

  4. Flagellin protein
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Movement of cilia and flagella in a eukaryotic cell is powered by ATP and these ATP molecules are hydrolysed into ADP+Pi in cilia and flagella by the activation of dynein protein
Nexin protein is found in cilia and flagella and it prevents microtubules from moving
Myosin of muscles- It is found in animals

Flagellin protein is found in flagella and it made up the structure of it.
so correct answer is  ' Dynein protein ' 

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

Rhizoplasts or rootlets, are the part of which of the following structure?

  1. Centriole

  2. Root hairs

  3. Ciliary apparatus

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

Rhizoplast is a fibril which is a connecting link between blepharoplast, with the nucleus in flagellated cells or organisms. It is a striated contractile structure attached to the basal region of the cilium in a variety of ciliates and flagellates. Many regulate the flagellar beat pattern, and is sensitive to calcium concentration. They are composed of a 20 kD protein, rather similar to spasmin. The ciliary rootlet or rhizoplast, is a cytoskeleton-like structure that originates from the basal body at the proximal end of a cilium. It extends proximally toward the cell nucleus. Rootlets are typically 80-100 nm in diameter and contain cross stria distributed at regular intervals of approximately 55-70 nm. 


So, the correct answer is option C.

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

The cilia and flagella arise from

  1. Basal bodies

  2. Basal granules

  3. Blepharoplasts

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

A basal body (synonymous with basal granule, kinetosome and in older cytological literature with blepharoplast) is an organelle formed from a centriole, and a short cylindrical array of microtubules. It is found at the base of a eukaryotic undulipodium (cilium or flagellum) and serves as a nucleation site for the growth of the axoneme microtubules. Centrioles, from which basal bodies are derived, act as anchoring sites for proteins that in turn anchor microtubules within centrosomes, and are known as the microtubule organizing center (MTOC).

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

Cartwheel structure is shown by

  1. Flagella

  2. Cilia

  3. Centriole

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

Centrosome is composed of two centrioles lying at right angles to each other. Each centriole has a cartwheel constitution. There is a whorl of nine peripheral triplet fibres of tubulin tilted at an angle of 40 degrees. In cilia and flagella also the cartwheel structure is present but the fibrils have 9+2 arrangement- peripheral doublet fibrils are tilted at an angle of 10 degrees.

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.'