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1. BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE:
BIOCHEMISTRY LECTURE
COURSE MODULE COURSE UNIT CLASS SESSION WEEK
1 1 1 1
Cell
 Read course and unit objectives
 Read study guide prior to online attendance
 Read required learning resources; refer to unit
terminologies for jargons
 Proactively participate in online discussions
 Participate in weekly discussion board (Canvas)
 Answer and submit course unit tasks
At the end of this unit, the students are expected to:
Cognitive:
1. Define correctly the cell and its organelles.
2. Compare accordingly the eukaryotic cell and prokaryotic cell.
3. Know in details the different organelles and discuss their structures and functions.
4. Distinguish correctly the various membrane transport mechanism and discuss their function.
5. Know correctly the cell life cycle.
Affective:

2. 1. Listen attentively during online discussions
2. Demonstrate tact and respect when challenging other people’s opinions and ideas
3. Accept comments and reactions of classmates on one’s opinions openly and graciously.
Psychomotor:
1. Participate actively during online discussions
2. Confidently express personal opinion and thoughts in online discussions
Mescher, A.L. Junqueria’s Basic Histology, 13th
edition. McGraw-Hill Education, 2013, (pp. 25-72).
(15 points)
Rao, M.N. Medical Biochemistry, 2nd
edition, New Age International Publishers, 2006, (pp. 1-9).
(5points)
Overview of the Cellular Basis of Life
The cell is coined as the basic living unit of all organisms. Most cells are specialized to perform
certain functions. If chemically analyzed, cells are composed primarily of four significant elements -
carbon, oxygen, hydrogen, and nitrogen. Knowing the basic function of each organelle makes it
possible to understand on how these organic compounds (i.e. carbon, oxygen) are responsible for
any biological events in the human body to maintain homeostasis and also to explain how different
sequences of biochemical reactions interact with each other for survival of cell (organism) under
various conditions.
Historical Notes on Cell
 Robert Hooke was the first person to use the term “cell”. He referred to the small empty
chambers in the structure of cork as cells.
 Matthias Schleiden and Theodor Schwann concluded that all plant and animal tissues were
composed of cells.
 Rudolf Virchow proposed the theory of biogenesis where cells only arise from pre-existing
cells.
Cell Theory
 A cell is the basic structural and functional unit of living organisms. So, when you define cell
properties, you are in fact defining the properties of life.
 The activity of an organism depends on the collective activities of its cells.

3.  According to the principle of complementarity, the activities of cells are dictated by their
structure (anatomy), which determines function (physiology).
 Continuity of life has a cellular basis.
Types of Cell
On the basis of differences in cell structure, all life forms are divided into two major classes.
 Eukaryotic cell is composed of organelles that are membrane bound structures, each having
a unique role and containing a specific complement of proteins and other molecules.
 Prokaryotic cell is lack of membranous subcellular organelles which are possessed by the
eukaryotes, but they are still able to perform the necessary processes of life.
Comparison Between Eukaryotic Cell and Prokaryotic Cell
EUKARYOTES PROKARYOTES
DNA is found in the nucleus of the cell. DNA is not enclosed within the membrane.
Contain membrane-bound organelles which
include mitochondria, endoplasmic reticulum, and
Golgi complex
Lack membrane-enclosed organelles
Cell division involve mitosis. Usually divide by binary fission.
Example of a Generalized Cell
(Photo from Junqueria’s Textbook)

4. Eukaryotic Cell Structure and Function
In eukaryotes, cells aggregate to form tissues or organs and these are further organized to form
whole organism. In humans, eukaryotic cells exist in large number of sizes and shapes to perform
varieties of functions. Eukaryotes contain subcellular structures and well-defined nucleus.
 Plasma Membrane
o Structure: Phospholipid bilayer containing cholesterol and proteins and some
carbohydrates; forms a selectively permeable boundary of the cell.
o Functions: Acts as a physical barrier to enclose cell contents; regulates material
movement into and out of the cell; functions in cell communication
 Nucleus
o Structure: It is enclosed within a double membrane called nuclear envelope;
contains nucleolus
 Nucleolus: It consists of RNA and proteins which functions in ribosomal unit
assembly.
 Nucleoplasm: It surrounds the chromatin and the nucleoli.
o Function: It contains the DNA that serves as the genetic material for directing protein
synthesis.
 Cytoplasm
o Structure: This can be seen between the plasma membrane and the nucleus where
the other cellular elements are embedded.
 Organelles are membrane-bound structures which carry out specific metabolic
activities of the cell.
 Cytosol provides support for organelles and serves as the viscous fluid
medium.
o Function: It is responsible for various cellular processes.
 Endoplasmic Reticulum
o It is further subdivided into:
 Rough endoplasmic reticulum
 Structure: Extensive interconnected membrane network that varies in
shape; ribosomes attached on the cytoplasmic surfaces
o Ribosomes are involved in the protein synthesis.
 Functions: Modifies, transports, and stores proteins produces by
attached ribosomes
 Smooth endoplasmic reticulum

5.  Structure: Extensive interconnected membrane network lacking
ribosomes
 Function: Synthesizes, transports, and stores lipids; detoxifies drugs;
forms vesicles and peroxisomes
 Golgi Apparatus
o Structure: Series of several elongated, flattened saclike membranous structures.
o Functions: Modifies, packages, and sorts materials, that arrive from the endoplasmic
reticulum in transport vesicles
 Vesicles transport cellular material. Mature vesicles are called secretory
vesicles.
 Mitochondria
o Structure: Double-membrane-bound organelles containing a circular strand of DNA
 Outer membrane is highly permeable to small molecules, due to the presence
of a pore-forming protein called porin.
 Intermembrane contains many proteins that participate in oxidative
phosphorylation.
 Inner membrane has multiple folds projecting inwards, called cristae.
o Function: It is responsible for the production of energy in the form of ATP.
 Lysosomes
o Structure: Spherical shaped membrane bound organelles formed from the golgi
apparatus; contain digestive enzymes
 The fluid inside lysosomes is much more acidic, at about pH 4.8, than the
normal pH of about 7.0–7.3.
o Function: Digest microbes or materials by the cell
 Peroxisomes
o Structure: Small vesicles surrounded by a membrane
o Function: Involved in the biosynthesis of cholesterol (peroxidase enzymes)
 Cytoskeleton
o Structure: Organized network of protein filaments
o Function: Maintains integral structural support and organization of cells
 Microfilaments maintain cell shape.
 Intermediate filaments give mechanical support to structures like nucleus
and plasma membrane.
 Microtubules provides structural support.
Some Important Notes in Prokaryotic Cell
 Prokaryotes (Eubacteria and Archaebacteria) are the most abundant organisms on earth.
 A prokaryotic cell does not contain a membrane-bound nucleus.
 Each prokaryotic cell is surrounded by a plasma membrane.

6.  The cell has no subcellular organelles, only infoldings of the plasma membrane called
mesosomes.
 The deoxyribonucleic acid (DNA) is condensed within the cytosol to form the nucleoid.
 Some prokaryotes have tail-like flagella.
Cell Membrane Transport
In order for chemical reactions to occur, the reagents must be placed appropriately along with their
enzyme catalysts. All cells have a plasma membrane, which is a barrier to the movement of
substances that are not membrane soluble. The movement of compounds across this and other
intracellular membranes depends on the chemistry of the molecule and often requires specialized
transport mechanisms.
Passive Transport Process
 Diffusion is the movement of a substance from an area of its higher concentration to an area
of its lower concentration.
o Simple diffusion is the type of diffusion of
dissolved solutes through the plasma
membrane
o Facilitated Diffusion is the type of diffusion
that requires a protein carrier.
o Osmosis is the diffusion of water point
across a selectively permeable membrane
Example of Diffusion
(Photo from basicmedicalkey.com)
Active Transport Process
 This type of cell membrane transport uses energy (ATP) provided by the cell.
o For example, cell has low intracellular sodium; but concentration of potassium inside
the cell is very high. This is maintained by the sodium–potassium activated ATPase,
generally called as sodium pump.
Sodium-Potassium Pump
(Photo from socratic.org)

7.  Exocytosis refers to bulk movement of substance out of the cell by fusion of secretory vesicles
with the plasma membrane.
 Endocytosis refers to bulk movement of substance into the cells by vesicles forming at the
plasma membrane.
Cell Life Cycle
 Interphase
o It is the longer phase of the cell cycle where the cell is active and preparing for cell division.
o The DNA molecule is duplicated exactly in a process called DNAreplicationwhich occurs
toward the end of the interphase.
 Cell Division
o Cells arise from the division of other cells.
o Mitosis consists of four stages-prophase, metaphase, anaphase, and telophase.
The result is two daughter nuclei, each identical to the mother nucleus.
 Prophase- each chromosome consists of two chromatids joined at the
centromere.
 Metaphase- chromosomes align at the center of the cell
 Anaphase- chromatids separate at the centromere and migrate to opposite
poles.
 Telophase- two new nuclei assume their normal structure, and cell division is
completed, producing two new daughter cells.
.
 Eukaryotic cell is composed of organelles that are membrane bound structures, each having
a unique role and containing a specific complement of proteins and other molecules.
 Prokaryotic cell is lack of membranous subcellular organelles which are characteristic of the
eukaryotes, but they are able to perform the necessary processes of life.

8. Cooper GM. The Cell: A Molecular Approach. 2nd edition. Sunderland (MA): Sinauer Associates;
2000. The Molecular Composition of Cells. Available from:
https://www.ncbi.nlm.nih.gov/books/NBK9879/
Study Questions
General Directions: Explain your answer with a maximum of 250-300 words. Support your answer
with references.
 Why is it essential that the medical personnel give only the proper intravenous solutions to the
patients? (5 points)
 What are the effects of IV solutions of varying tonicity on living red blood cells? (5 points)
 Why do phospholipids (which form the bulk of plasma membranes) organize into a bilayer, tail to
tail, in a watery environment? (5 points)
Rubrics:
5- The student answered the questions correctly and in detailed manner and answers were
supported with references appropriately.
3- The student answered the questions correctly, but with some missing points and the answers
weren’t supported with references.
1- The student answered the questions incorrectly and the answers weren’t supported with
references.
Engelkirk, P.G. and Engelkirk, J.D., Microbiology for Health
Sciences. 9th
edition. Lippincott Williams& Wilkins, 2011, (pp. 25)
Mescher, A.L. Junqueria’s Basic Histology, 13th
edition. McGraw-Hill
Education, 2013, (pp. 25-72).
Rao, M.N. Medical Biochemistry, 2nd
edition, New Age International
Publishers, 2006, (pp. 1-9).