Role of CYTOPLASM AND NUCLEUS IN DEVELOPMENT

1. ROLE OF
CYTOPLASM AND
NUCLEUS IN
DEVELOPMENT
5th DECEMBER

2. •ROLE OF CYTOPLASM:
• It is known that different cytoplasmic components
contain different morphogenetic determinants that
are responsible for cell differentiation.
• These determinants are present in blastomere.
a cell formed by
cleavage of a fertilized
ovum.
Things that activate genes to determine the
morphology

4. •The fertilized egg of Ascidian
(tunicates) contains cytoplasm of four
different colors that is segregated into
different blastomeres.
•
1. CLEAR CYTOPLASM produces larval epidermis
1. YELLOW CYTOPLASM Gives rise to muscle cell
1. GREY VEGETAL CYTOPLASM Gives rise to GUT.
1. GREY EQUITORIAL CYTOPLASM Produces
NOTOCHORD and NEURAL TUBE.

5. •ROLE OF NUCLEUS IN DEVELOPMENT
•Most gene controlling substances are
found in cytoplasm and thought to be
produced in it.
•It was thought that the morphogenetic
determinants are produced in the nucleus
or in it’s surroundings.

6. •Haemmerling’s Experiment to study
control of NUCLEUS:
• Joachim Hämmerling was a German Botanist, in
1943 he performed an experiment to prove that it is
nucleus that controls the morphology of an
organism and cytoplasm just activate genes to
express morphology of an organism.
• He took an ALGAE, ACETABULARIA which exist in
two morphological forms
• 1. With regular cap Mediterrania
• 2. With Irregular cap Crenulata

7. •Acetabularia is:
• Green Algae
• Unicellular and
• Has two morphological species Mediterranea and
Crenulata.
Hammerling took both species and removed their caps .
He then joined the stalk of Mediterranea on the rhizoid of
crenulata containg the crenulata’s nucleus and
He joined the stalk of crenulata on the mediterranea’s
rhizoids containing the nucleus of mediterranea’s nucleus
This means only the cytoplasm of two species are
exchanged not their nucleus.

8. RESULTS

9. •RESULTS:
• The Mediterranea with the stalk containing
cytoplasm of Crenulata developed into regular cap.
• The Crenulata with the stalk containing cytoplasm
of Mediterranea developed into regular cap.
•FINDINGS:
•Nucleus bears genes.
•Cytoplasm activate the genes.