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1. CELL SIGNALING,
REGULATING MECHANISM
AND CYTOPLASM

2. Cytoplasm
• Consists of 80%-90% water, and salts,
organic molecules, enzymes, proteins and
nutrients
• Moves cellular materials through a
cytoplasmic streaming mechanism
• Maintains shape and consistency of cell
• Storage space for chemical substances
• Good conductor of electricity

3. Nucleus
• Largest organelle in cell
• Uninucleate, binucleate,
multinucleate
• Bounded by nuclear
envelope
• Nucleomma Cisterna
• Houses the genetic
material

4. Nucleus
• Regulates metabolic process in cell
• Distributes genetic material equally
• Site for separation of chromosomes
during cell division

5. Ribosome
• Large and small subunit
• Primary site in the process of
protein synthesis
• Can be found in groups or
alone
• Attached to Endoplasmic
Reticulum

6. Endoplasmic Reticulum
• Complex internal membrane
system
• Flattened sheets, sacs and tubes
• Makes proteins and shuttles
cellular products
• Involved in metabolism of fats,
production of various materials
• Rough ER, smooth ER

7. Rough ER
• Connects polysaccharide groups to the
polypeptide
• Proteins not destined for cytoplasm is
synthesized here

8. Smooth ER
• Involved in synthesis of lipids and hormones
• Storage for calcium ions
• Breaks down toxins and drugs in liver cells

9. Golgi Apparatus
• Central delivery system of cell
• Modify or package proteins and
lipids into vesicles
• Transports lipids
• Creates lysosomes and organelles
involved in digestion

10. Lysosome
• Contains powerful degrading
enzymes
• Built in the Golgi Apparatus
• Breaks down harmful products, waste,
bacteria
• Tay-Sachs, Pompe’s diseases are
examples of lysosome malfunction

12. Peroxisomes
• Oxygen is used to oxidize substances
• Breaks down lipids and detoxifies
chemicals
• Self replicates by enlarging then
dividing
• Can convert hydrogen peroxide to
water

14. Mitochondria
• Generates ATP
• Found near the nucleus
• Cristae are formed from folds in the inner
membrane
• Have their own DNA
• Similar traits with bacteria

15. Signal Transduction

16. • Forms of intercellular signaling

17. Extracellular signal molecules bind to
specific receptors

18. Autocrine Signaling
A way for a cell to alter its own extracellular
environment. The cell secretes chemicals
outside of its membrane and the presence of
those chemicals on the outside modifies the
behavior of that same cell. This process is
important for growth.

20. Paracrine Signaling
A way for a cell to affect the behavior of
neighboring cells by secreting chemicals
into the common intercellular space.

21. Endocrine Signaling
Utilizes hormones. A cell secretes chemicals
into the bloodstream. Those chemicals affect
the behavior of distant target cells.

22. Direct Signaling
A transfer of ions or small molecules from one
cell to its neighbor through pores in the
membrane. Those pores are called gap
junctions. This is the fastest mode of cell-cell
communication.

23. Synaptic Signaling
It is found in the nervous system. It is a
highly specific and localized type of
paracrine signaling between two nerve
cells or between a nerve cell and a
muscle cell.

25. Nitric oxide gas signals by binding directly
to an enzyme inside the target cell

27. Cell Receiving Signals
• Some small molecules are capable of entering
the cell through the plasma membrane.
• Some small hormones also enter the cell
directly, by passing through the membrane.

28. There are three types of cell surface receptors:

29. M) Signaling via G protein linked receptors
adenylylG protein
bg a
receptor
membrane
cytosol
extracellular
space
cyclase
GDPligand
GTP
ATP
cAMP
Pi
Some G proteins
regulate the
production of cAMP

30. What is the cAMP?

31. Some G proteins activate the inositol
phospholipid signaling pathway by
activating phospholipase C-b

32. Ion Channel Receptors
• When a signaling molecule binds to an ion
channel on the outside of the cell, this triggers
the change of the conformation of the protein
and the channel opens, allowing the ions to
move in or out of the cell following their
electrical gradients

34. Transmembrane Receptors
• Transmembrane proteins include G protein-
linked receptors and they are seven-pass
trans membrane proteins. This means that the
polypeptide chain traverses the membrane
seven times.

36. Triggered Chemical Reactions
• the movement and binding of the G-
protein
• transformation of GTP into GDP
• activation of second messengers

37. Ca2+ functions as an intracellular second
messenger
• Three main types of Ca2+ channels that
mediate Ca2+ signaling:
1. Voltage dependent Ca2+ channels in the plasma
membrane
2. IP3-gated Ca2+-release channels
3. Ryanodine receptors

38. The concentration of Ca2+ in the
cytosol is kept low in resting cells

40. Thank You For Your
Time