Cell signaling occurs through two main types: electrical signals using ions and chemical signals using signaling molecules. The majority (60-70%) of drugs bind to G protein-coupled receptors (GPCRs). Muscle contraction, writing, and boxing occur due to nicotinic acetylcholine receptor ion channels. Signaling molecules act by binding to receptors and are also called ligands. Signaling molecules can be agonists, which stimulate pathways, or antagonists, which inhibit pathways. End targets of cell signaling include transport proteins, cytoskeleton, enzymes, and genes. Signaling mediators include adapter proteins, effectors, cAMP as a second messenger, and protein kinases. Scaffold proteins cause localization of signaling mediators

1. (For all competitive
exams)
Important points for
Life Sciences

2. 1.) Cell signaling are of two
types. What are they?

3. Electrical
signals(ions)
Chemical
signals(signaling
molecules)

4. 2.) 60-70% of drugs bind to
which kind of receptors?

5. Ans.) GPCR (These are
Pharmacological agonists)

6. 3.) Muscle contraction
occurring, writing, boxing are
being happened because of
________?

7. Ans.) Nicotinic Acetylcholine
receptor Ion channel.

8. 4.) Intracellular receptors
means receptors on____?

9. Ans.) Organelles

10. 5.) Signalling molecule act by
binding to the receptor and are
also called as _______?

11. Ligand.

12. 6.) Signalling molecules are 2
types. What are they?

13. Agonists(stimulate a
pathway)
Antagonists(inhibit a
signaling pathway)

14. 7.) What are the different End
targets in Cell signaling?

15. Transport protein
Cytoskeleton
Enzymes
Genes

16. 8.) Signalling mediators are?

17. Ans.) Adapter proteins,
Effectors,
cAMP(2nd messenger)
and Protein kinases
(Transcriptional factors are also signaling
mediators only when Genes are end targets)

18. 9.) The proteins that make few
signaling mediators in a
particular line and not to get
disturbed are called______?

19. Ans.) Scaffold proteins (These
proteins cause physical co-
localization of a few signaling
mediators)

20. 10.) ______ is a Scaffold
protein in Yeast?

21. Ans.) Ste-5

22. 11.) Interaction of 2 or more
pathways is called as ______?

23. Ans.) Cross-talk

24. 12.) In Juxtacrine signaling,
the signaling molecule is
expressed as a Plasma
membrane component. This
signaling process is also
called as ____?

25. Ans.) “Contact-dependent
signaling pathway”.
(Note: In Autocrine signaling the signaling
molecule is released whereas in Juxtacrine the
signaling molecule is not released.)

26. 13.) The Ovarian follicles that
tried to get matured undergo a
Programmed cell death
called____?

27. Ans.) Atresia

28. 14.) Oestrogen acts in +ve
Feedback manner in
Hypothalamus to secrete a
peptide signaling molecule
called____?

29. Ans.) “Kisspeptin” (this
happens on 9th day)

30. 15.) ______ is the major
ovulating hormone?

31. Ans.) Leutinising hormone

32. 16.) Estrogen and
Progesterone have two
functions. What are they?

33. Ans.) The two functions are:
a.) Acts as –ve feedback on
Hypothalamus to seize the
concentration of or release
of Gonadotropin and

34. b.) Enhances the condition of Endometrial lining for the possible
implantation of Fertilised egg:
i.) Promote proliferation of Endometrial Squamosa Epithelial cells
ii.) Increases Vascularisation
iii.) Increases thickness of walls
iv.) Promote formation of Endometrial glands &
v.) Increases Secretorial activity.

35. There are 3 types of termination mechanisms
for a pathway. They are:
A.) Making the
signaling molecule not
to be present in the
vicinity of receptor.
This is 2 types:
i.) Reuptake of
Signalling molecule
ii.) Degradation of
Signalling
molecule
B.) Making the receptor desensitize to the signaling
molecule. Ex: Phosphorylation of receptor
C.) Invagination of Signaling molecule-Receptor
complex(i.e internalization and degradation)

36. (These are the few important points for
Life Sciences competitive examinations).
Powerpoint template credits: fppt.com

37. THANK YOU.
Keep learning.
Be Happy.