Protozoa can reproduce both sexually and asexually. Asexual reproduction occurs through binary fission, multiple fission, budding, or plasmotomy. During binary fission, the protozoan undergoes karyokinesis and cytokinesis to form two daughter cells. There are four types of binary fission: longitudinal, transverse, irregular, and oblique. Sexual reproduction involves the fusion of gametes through processes like syngamy, conjugation, or endomixis. This introduces genetic variation and allows protozoa to survive unfavorable conditions. Important protozoa like Plasmodium reproduce using both asexual and sexual life cycles to complete their development within the host.

1. REPRODUCTIO
N IN
PROTOZOABy
VYSHNAV P V
M.Sc. Microbiology (2020-2022)
Department of microbiology
Central University of Punjab Mansa Road,
Bathinda

2. WHAT IS PROTOZOA ?

3.  WHAT is the Importance
of protozoa?
Parasitology, food chain
 PURPOSE OF
REPRODUCTION
Maintain the continuity
of generation
 TYPE OF
REPRODUCTION
Sexual & asexual

4. ASEXUAL REPRODUCTION
 without the fusion of nucleus
 During favourable condition
 Clone
 Different examples are
BINARY FISSION
 Common type
 Karyokinesis followed by cytokinesis
 Reconstruction of required materials
 Depending on the plane of fission binary fission is of the following
types.
 LONGITUDINAL BINARY FISSION
 TRANSVERSE BINARY FISSION
 IRREGULAR BINARY FISSION
 OBLIQUE BINARY FISSION

5. LONGITUDINAL BINARY FISSION
 It is common in Mastigophores (e.g.:
euglena
 cytokinesis takes place by a
longitudinal furrow from the
anterior end which proceeds
towards the posterior end
 Besides the nucleus, the organelles
that undergo division are
blepharoplasts and chloroplasts.
 'Symmetrogenic division‘
 What are Newly synthesized
organelle?
contractile vacuole, stigma and
paraflagellar body etc.

6. TRANSVERSE BINARY FISSION
 Mainly seen in a ciliated organism like
paramoecium
 Macronucleus able to controls vegetative function
while Micronucleus controls reproductive function
 macronucleus divides by amitosis process,
micronucleus divides by mitosis
 During cytokinesis a constriction appears in the
middle of the body, by the deepening of the
constriction transversely two daughter cells are
formed
 The anterior daughter individual is called –
PROTER
 The posterior daughter individual is called -
OPISTHE
 Organelle that is shared and newly appeared ??
 homothetogenic binary fission

7. IRREGULAR BINARY
FISSION
 no defined plane of fission
 Example: Amoeba
OBLIQUE BINARY
FISSION
 common in dinoflagellates
 the plane of fission is
oblique to the body axis of
the organism.
 Example: Ceratium

8. MULTIPLE FISSION OR SPORULATION
• Encysted animals nucleus get multiplied repeatedly
• Release of minute daughter nuclei
• Under favourable circumstances, the cyst bursts and these small animals come out
• common in sarcomastigophores and apicomplexans
GAMOGONY:
Example: plasmodium
SPOROGONY
• It occurs following sexual fusion
• Motile spores are known as swarmers or swarm spores. The swarmers are of two types
SCHIZOGONY OR AGAMOGONY
• It is an asexual reproduction method where schizonts were produced by the increased
number of division in sporozoites.

9. LIFE CYCLE OF PLASMODIUM

10. PLASMOTOMY
 A type of asexual reproduction in which
a multinucleate protozoan cell divides
into two or more multinucleate
daughter-cells without the occurrence
of mitosis. e.g.: Opalina
BUDDING
 daughter nuclei produced by mitotic
division migrate into a cytoplasmic
protrusion (bud) which is ultimately
separated from the mother cell by
fission
 monotonic budding, eg. Vorticella and
multiple buds are formed in Suctorians
 exogenous budding eg. Ephelota
 endogenous budding e.g. Acineta

11. ACINETA

12. SEXUAL
REPRODUCTION
• gametes fuse to form a new individual
• Able to survive unfavourable condition by
creating genetic variability
• involves the meiotic division.
SYNGAMY OR SEXUAL FUSION:
• complete and permanent union or fusion of two
specialised protozoan unit or gametes resulting in
the formation of a fertilized cell or zygote or
oospore
• Depending upon the degree of differentiation of
the fusing gametes syngamy may be of the
following types

13. ISOGAMY
 When two fusing gametes are similar in size and shape
 isogamy examples are Chlamydomonas, Cryptomonas
ANISOGAMY:
 When two fusing gametes, differ morphologically as
well as in behaviour
Example: Plasmodium and Volvox
OOGAMY
 Large non-motile gametes are fertilized by smaller
motile gametes, e.g., Plasmodium
HOLOGAMY:
 The two ordinary mature protozoan individuals do not
form gametes but themselves behave as gametes and
fuse together to form a zygote. Examples are Sarcodina
and Mastigophora

14. SIGNIFICANCE OF SYNGAMY:
 (i) Syngamy brings about a nuclear reorganization,
and physiologically it has distinct effects
 (ii) It brings two previously separated lines of
heredity in close association.
 (iii) It increases diversity among the offspring
 Automixis
In protozoa the nucleus divides into two, the two
nuclei fuse together, this is called automixis.
If the two nuclei that fuse are present in a single cell,
then the process is called autogamy
if the two fusing nuclei are present in two different
cells, then the process is known as paedogamy.

15. CONJUGATION

16.  CYTOGAMY
 There is no nuclear exchange in cytogamy. This process resembles conjugation
 pellicle of the 2 individuals does not break down
 The early nuclear division is similar to those of conjugation
ENDOMIXIS

17. HEMIXIS

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