This document provides an overview of cell biology for nurses. It describes the basic components and functions of eukaryotic cells, including the cell membrane, cytoplasm, organelles, and nucleus. Specifically, it discusses the structure and roles of the phospholipid bilayer, membrane transport mechanisms like passive diffusion and active transport via pumps, the cytoskeleton, ribosomes, mitochondria which generate energy in the form of ATP, and other organelles like the endoplasmic reticulum, Golgi apparatus, and lysosomes.

1. Biochemistry for nurses
Basic Biology for nurses: The Cell

2. Dr Hakim Mehenni
Email: dr.hakimmehenni.uqu@gmail.com
https://sites.google.com/site/drhakimmehenni/
Biochemistry for nurses

3. General informations on the cell
The cell is a basic unit of living organisms.
It can perform all the functions of the organism: metabolism, movement,
growth and reproduction.
There are 2 types of cells:
• Eukaryotic cell: It has a nucleus containing the genetic materials (ex: Human
cells).
• Prokaryotic cell: It doesn’t have a nucleus and the genetic material is free inside
the cell (ex: bacteria).
Biochemistry for nurses

4. General view of the eukaryotic cell
Biochemistry for nurses

5. The cell membrane
The cell is surrounded by a cell membrane (or plasma membrane)
The cell membrane is composed by:
• A bilayers of phospholipides
• Proteins (transmembrane,peripheral and intrinsic)
• Cholesterols
The cell membrane is composed by:
• A bilayers of phospholipides
• Proteins (transmembrane,peripheral and intrinsic)
• Cholesterols
Biochemistry for nurses

6. The phospholipid bilayersOil in water
Hydrophilic = Like water
Hydrophobic = Dislike water
Biochemistry for nurses

7. • To protect the cell
• To control the exchanges between the cell and the outside
environment (ex: Entrance of nutrients, disposal of wastes)
• To communicate with the outside environment (ex: others cells)
through protein receptors present in the cell membrane.
Functions of the cell membrane
Biochemistry for nurses

8. The membrane transports
The cell is alive! It needs the membrane transports in order to introduce
nutrients (O2, glucose, etc…) from outside to inside the cell, and to reject
wastes (CO2, urea, etc…) from inside the cell to outside
Different types of membrane transports:
1. Passive transport:
- simple diffusion
- facilitated diffusion
- osmosis (simple diffusion of water)
2. Active transport:
- Uniporter pump
- Symporter (co-transporter) pump
- Antiporter pump
3. Endocytosis and exocytosis
Passive= No need of energy!
Active= Need of energy!
Biochemistry for nurses

9. Passive transports No need of energy to work!
Simple diffusion
The simple diffusion is the movement of hydrophobic
molecules (ex: O2, CO2, N2) from an area where they are more
concentrated towards an area where they are less concentrated
(concentration gradient) directly through the phospholipids
bilayers membrane.
Biochemistry for nurses

10. Facilitated diffusion
The facilitated diffusion is the movement of hydrophilic molecules (Na+
, K+
,
glucose,etc…) from an area where they are more concentrated towards an area
where they are less concentrated (concentration gradient) through
transmembrane proteins (protein channels and carrier proteins).
Biochemistry for nurses

11. Facilitated diffusion
Protein
Channels for
Na+
and K+
diffusion
Biochemistry for nurses

12. Facilitated diffusion
Carrier
Protein for
glucose
diffusion
Biochemistry for nurses

13. OSMOSIS
The osmosis is the simple diffusion of water (H2O) directly through the cell membrane from
the area containing less solutes towards the area containing more solutes until equilibrating
of the concentrations.
Osmosis causes the electrolytes balance (Na+
, Cl-
, Ca2+
, K+
, etc…) on either side of
the cell membrane.
Biochemistry for nurses

14. Osmosis effect on red blood cells
Biochemistry for nurses

15. Active transports Need energy to work!
The active transports need energy to work because:
• Movement against or in absence of a concentration gradient.
• For hydrophilic molecules (ex: amino acids, glucose, Na+
, K+
, etc…)
which are not able to cross directly through the bilayers phospholipids membrane.
The active transports use 3 types of transmembrane proteins:
Biochemistry for nurses

16. ATP
ADP+Pi
Energy
HydrolysePhosphorylation
Hydrolyse of ATP provides a big energy
(35 KJ). Each day, you hydrolyse 1025
ATP molecules in your body
ATP (Adenosine Triphosphate) is a molecule
composed by an organic base (adenine) and a 3
phosphates group attached to a sugar (ribose).
ATP molecule is the source of ENERGY!
Biochemistry for nurses

17. ATP molecule is
the source of
ENERGY!
CELL METABOLISM (cell respiration)
ATP is manufactured inside the
mitochondria from the transformation
of the energy coming from the
absorbed foods into a chemical
energy stored in the chemical bond
with the 3rd
phosphate group.
Biochemistry for nurses

18. Na+
/K+
/ATPase Pump (Antiporter)
The Na+
/K+
/ATPase Pump is present in
the cell membrane.
The Na+
and K+
ions play many
important roles in our body! For example
they maintain the electrochemical
potential of electrically excitable cells
(ex: neurone or nerve cell).
Biochemistry for nurses

19. Ca2+
/ATPase Pump (uniporter)
The Ca2+
/ATPase Pump is present in the
endoplasmic reticulum membrane
and the cell membrane.
The Ca2+
ions play an important role as
second messenger in neurotransmitter
release from neurons and in contraction
of all muscle cell types.
Biochemistry for nurses

20. Sucrose co-transporter pump (symporter)
Biochemistry for nurses

21. Endocytosis and exocytosis transports
Endocytosis occurs by invagination of the cell membrane to form vacuoles
(Cells of the immune defense).
Exocytosis releases intracellular molecules to outside the cell. The molecules
are transported in vacuoles (ex: Insulin released by the pancreatic cells (release of
hormones))
Biochemistry for nurses

22. The cytoplasm
The cytoplasm is the entire cellular material delimited by the cell membrane.
It is composed by:
1. The cytosol liquid (85% of water, pH = 7):
The cytosol contains simple molecules, macromolecules, dissolved gases (O2,
CO2), ions (Na+
, K+
, Ca2+
…)
2. The cell organites.
There are 2 types of organites: Surrounded and non surrounded by a membrane
Biochemistry for nurses

23. Organites non surrounded by a membrane
Biochemistry for nurses

24. The cytoskeleton
The cytoskeleton is a dynamic
protein structure: It is a
skeleton and a musculature in
same time for the cells. The
cytoskeleton has the function to
maintain the shape of the cell,
to create a cell movement. It is
involved in the cell division.
Biochemistry for nurses

25. The ribosomes are spherical proteins which have the function to
synthesis the proteins in the cell. They convert the instructions found in messenger
RNA ( mRNA, which itself is made from instructions in DNA) into chains of amino-
acids that make up proteins.
Biochemistry for nurses

26. The centrosome is made by 2 centrioles which are protein tubules.
The centriole is composed by 9 triplets of 3 protein tubules. Its function is to manage
the movement direction during the cell division.
Biochemistry for nurses

27. Organites surrounded by a membrane
Biochemistry for nurses

28. The endoplasmic reticulum (ER)
are organites with networks of intracellular
membranes. The ER functions are to act as
a manufacturing and packaging system.
They are 2 types of endoplasmic reticulum:
• Rough endoplasmic reticulum (RER) who
has its surface covered by ribosomes which
assemble the amino-acids into proteins. The
RER is connected with the membrane
nucleus. RER is a packaging system of
proteins.
• Smooth endoplasmic reticulum (SER) who
doesn’t have ribosomes on its surface. The
SER is involved in the synthesis and
packaging of lipids, in the storing of calcium
(Ca2+
) and in the detoxification of the cell.
Biochemistry for nurses

29. The Golgi Apparatus is
composed of bags flattened on the
others. He has the function to store
the synthesized proteins coming
from the rough endoplasmic
reticulum. Then the proteins are
concentrated inside vesicles in
order to be secreted outside the cell
by exocytosis. In summary the
golgi apparatus plays a role of
storing and secretion of the
proteins.
Biochemistry for nurses

30. The Lysosomes are vesicles containing digestive proteins (digestive enzymes)
coming from the golgi apparatus. The lysosomes are the location of the cell digestion
in which damaged organites, macromolecules and toxic molecules are destroyed.
Biochemistry for nurses

31. The mitochondria is an organite having a double intracellular membrane. The
mitochondria is the location of the ATP synthesis (ATP = source of ENERGY!) in
presence of glucose and oxygen (O2) by a processus called « Cell Respiration ». The
muscular cells have a large number of mitochondria.
Biochemistry for nurses

32. Inside the mitochondria!
Biochemistry for nurses
Phosphorylation
Hydrolyse

33. The nucleus is limited by a nuclear envelope containing:
• The chromatin which is composed of DNA (DeoxyriboNucleic Acid = genetic
support of the cell).
• The nucleolus is the location of the DNA transcription (= synthesis of mRNA)
•The nucleoplasm is the liquid inside the nucleus.
The nucleus is the brain of the cell!
Biochemistry for nurses

34. The diameter of the nucleus is between 10 to 20 um.
The nucleus has 2 main functions:
1. To control the biochemical reactions of the cell.
2. To save the genetic informations required for the
life of the cell and its reproduction
Biochemistry for nurses