Inter First Year Zoology Unit V Important Questions for 2 Marks

Q: List out any two differences between a flagellum and a cilium.
A:
Flagellum:
a. It is a long and whip like structure.
b. Flagellae generally originate in the anterior part of the body.
c. flagellae exhibit undular movements.

Cilium:

a. It is a short and hair like structure.
b. Cilia are present all over the body or confined to peristome only.
c. Cilia exhibit pendular movements.

Q: Draw a labelled diagram of T. S. of flagellum.
A:

Inter First Year Zoology 2 Marks Important Questions - Unit V

Q: What is a kinety?
A: In ciliate protozoans, a row of kinetosomes along with kinetodesmata constitute a kinety. It lies just below the pellicle.

Q: What are dynein arms? What is their significance?
A: a. Each A tubule of the each peripheral tubule of flagellum has a pair of arms,
known as dynein arms. They extend towards B tubule of the adjacent doublet.
b. Dynein arms help in bending of flagellum.

Q: Differentiate proter and opisthe.
A: During binary fission in Paramecium, the daughter individual formed from the anterior
half of the parent is called proter and that is formed from the posterior part is
known as opisthe.

Q: Define conjugation with reference to ciliates. Give two examples.
A: Temporary union of two ciliates for the exchange of micronuclear material is
known as conjugation. Eg: Paramecium, Vorticella.

Q: Why do we refer to the offspring formed by asexual method of reproduction, a
clone?
A: As the daughter individuals formed by asexual reproduction are morphologically
as well as genetically similar to that of the parent organism, they are described as
a clone.

Junior Intermediate Zoology Unit - V Important Questions for 4 Marks

Q: Describe the process of longitudinal binary fission in Euglena.
A: Longitudinal binary fission takes place in Euglena during favourable conditions.
The division of nucleus during binary fission is known as karyokinesis and that of cytoplasm is called cytokinesis.

Euglena is a common protozoan in fresh water bodies and is green in colour due to
presence of chromatophores containing chlorophyll. Euglena is a spindle shaped individual having two flagellae in the anterior end arising from two basal granules
besides cytostome, cytopharynx, reservoir, contractile vacuole, stigma, paraflagellar
body etc. Almost in the middle of the body, there is a nucleus.

a. During binary fission, nucleus divides by mitosis.
b. Then the basal granules and chromatophores also divide.
c. A constriction appears in the anterior end, grow deep dividing the parent Euglena into two daughter Euglenae.
d. The basal granules and flagellae are retained by one daughter and the other acquires new flagellae from the newly formed basal granules.
e. Stigma, paraflagellar body and contractile vacuole of the parent disappear and new
structures are formed in both daughter Euglenae.
f. As the daughter Euglenae formed after longitudinal binary fission are like mirror
images, the binary fission in Euglena is also called symmetrogenic division.

Q: Write short notes on multiple fission.

A: Division of the parent individual into many daughter individuals is known as multiple fission. Generally, multiple fission takes place during unfavourable conditions. In multiple fission, nucleus of the parent individual divides many times by mitosis. Thus many nuclei are formed. Each nucleus is surrounded by a bit of cytoplasm and thus many small daughter individuals are formed. When the body covering of the parent ruptures, all the daughter individuals are liberated out and each one develops into a complete organism.

Eg: Multiple fission in Plasmodium is described as schizogony, male gametogony
and sporogony.
Multiple fission in Amoeba is known as sporulation.

Q: Draw neat labelled diagram of Euglena.
A: