Cell biology

‫الرحيم‬ ‫الرحمن‬ ‫هللا‬ ‫بسم‬
UNIVERSITY OF ALBUTANA
Faculty of Medical Laboratories
science
2/13/2021 By :Wijdan Abdu Mohammad

Lecture (1)

• About me and course
• The course outlines
• Concept of cell biology
• Cell theory

Lecturer : Wijdan Abdu Mohammad Edrees
Email : Wijdan243.Abdu@gmail.com
Course name: Cell Biology
Course code : MLsBO114
Credit hours : 2(1+2)
13-Feb-21 By : Wijdan Abdu Mohammad

The course outlines
Introduction to cell structure and function
Types of cells
The cell membrane structure and function
The cytoplasmic organelles
The cytoplasmic matrix
The cytoplasmic structure and function
The nucleus structure and function
The cell cycle and cell division

The evaluation
Final exam 50
Practical 30
Attendance 10
Essay 5
Quiz 5

References

What do we mean by cell biology?

Cell biology
Is a biological science that deals with the study of structure,
function, molecular organization, growth reproduction and
genetics of the cells.
Cell biology = cytology

Cell
Is the fundamental unit of live
It is too small to be seen with naked eye
Some cell can bee seen with naked eyes

Cell theory
Principles of cell theory:
1- All living organsims are composed of one or more cells
2- Cells are the basic units of structure and function of the livings
organism.
3- Cells can raise only by division come preexisting cell.

The cell has been studied by the following three
avenues:
• Classical cytology deal with only light microscopically
visible structure of the cell.
• Cell physiology studied biochemistry, biophysics, and
functions of the cell.
• Cell biology interpreted the cell in terms of molecules
(macromolecules such as nucleic acids and proteins).

CELL BIOLOGY AND OTHER BIOLOGICAL SCIENCES

• Due to its wide application in various branches of biological
science, many new hybrid biological sciences, have sprung up.
Some of them are as follows:
1- Cytogenetics (Cytology and Genetics).
Cytogenetics is branch of cell biology which is concerned
with the cytological and molecular bases of heredity, variation,
mutation, phylogeny.

2- Cytotaxonomy (Cytology and Taxonomy).
Each plant and animal species has a definite number of
chromosomes in its cells.
the chromosomes of the individuals of a species resemble closely
with one another in shape and size.
Cytotaxonomy can be defined as a cytological science which
provides cytological support to the taxonomic position of any
species.

3- Cell Physiology (Cytology + Physiology).
The cell physiology has helped in understanding various
complicated physiological activities at cellular level.
4. Cytochemistry (Cytology +Biochemistry).
The cytochemistry deals with the chemical analysis of living
matter. For example carbohydrates, protein and nucleic acids .

5. Ultrastructure and Molecular Biology.
These are the most modern branches of biology in which the
merging of cytology with biochemistry.
6. Cytopathology (Cytology + Pathology).
7. Cytoecology (Cytology +Ecology).
studies the effects of ecological changes on the chromosome
number of the cell.

Thanks

Lecture 2

The objective :
To know the cell types and diversity

Diversity of cells
• Cells are not all alike , in fact they are widely different in size ,
shape , internal organization and even in their needs.
• Not all cells are alike even those in one organisms .

Diversity of cells
1. Size
Cells are come in different sizes , most of them are very small
and they need a mean to be seen Ex :
Bacteria , White blood cell , RBCs.
while others are large enough and can be seen with necked eye
Ex :
Human egg (ova)

Diversity of cells
2. Shape :
Cells diverse in their shape and structure according to their
function:
Ex :
Nerve cell
Red blood cell
Muscle cell

Diversity of cells
3. Internal organization:
The content and composition of cells have some
diverse according to their function as in RBC it lose the
nucleus to be able for caring large amount of oxygen .

Diversity of cells
4.Cells differ in heir need :
Some cell need sunlight for their nutrition , some need
complex molecule, while others need specific molecules
such as minerals .
Cancerous cells need more oxygen for its growing.

Types of cells
• The presence or absence of the nucleus is used
as basis for simple but fundamental
classification of all living things into two main
categories:
Prokaryote
Eukaryote

The prokaryote
• Is an organism whose cells have no nucleus.
• Spherical , rod like , small about a few micrometer in
long.
• They reproduce quickly by dividing into two.

Prokaryotic

The Eukaryote
• Is an organisms have a nucleus and varity of many
other internal organelles
• Bigger and more elaborated than prokaryotes.
• Include plants, animals, and fungi.
Note :
Amoeba is a single cell eukaryotic organism.

Eukaryotic cell

The end

Lecture 3&4

The objective :
To know the cytoplasm function and structure .

The parts of cell
1- Nucleus
2- Cytosol ( cytoplasmic matrix )
3- Organelles
4- cell membrane or cell wall

Cytosol :
Is the jelly-like mixture in which the other organelles
are suspended.
Cytoplasm = cytosol + organelles

Cytoplasm
• Everything within the cell membrane which is not the nucleus
is known as the cytoplasm
• Cytoplasm present between plasma membrane and nucleus .
• Cytoplasm have two portion :
1- liquid portion ( cytosol)
2- Other portion ( organelles)

What about the liquid portion???
Lipids
Carbohydrate
Protein
Electrolyte.

Cytoplasmic matrix function
• Raw materials
• Exchange
• Products
• Biosynthesis
• Metabolic activity
• Cytoplasmic streaming

The organelles
• Mitochondria
• Endoplasmic reticulum
• Golgi apparatus
• Lysosomes
• Peroxisomes
• Cytoskeleton
• Secretory vessels

The function of cytoplasm
• Breaking down waste
• Help metabolic activity
• Give the cell shape
• Keep organelles in place

Lecture 5

The objective :
To know the function and importance of cellular
organelles.

What are the cytoplasmic organelles ?
Cytoplasmic organelles

Endoplasmic Reticulum (ER)
• The endoplasmic reticulum, or ER,
consists of stacks of flattened sacs.
• involved in the production of various
materials.
• Rough ER associated with the
nucleus, the ribosomes are present
there
• Smooth ER, without ribosomes, is
• responsible for various activities,
including the synthesis of lipids
hormones.

Golgi apparatus
• Golgi apparatus (Golgi complex or
Golgi body) is a group of flattened
sacs .
• They function to modify and
package proteins and lipids into
vesicle.
• shaped sacs that bud from the ends
of a Golgi apparatus. Vesicles
migrate to and merge with the
plasma membrane, releasing their
contents outside of the cell

Lysosomes
• Lysosomes are vesicles from
a Golgi apparatus that
contain digestive enzymes ,
They break down food,
cellular debris, and foreign
invaders such as bacteria.

Mitochondria
• Mitochondria carry out
aerobic respiration, a
process in which energy (in
the form of ATP) is obtained
from carbohydrates. The
mitochondria
• Can also produce energy
from non carbohydrate
sources such as fats.

Chloroplast
• Found in green plant cells
• Is responsible from
photosynthesis
• Convert the sun light into
energy in form of ATP

Ribosomes
• Ribosomes carry out the
process of producing
protein.

Peroxisomes
• Are organelles common in
liver and kidney cells that
• break down potentially
harmful substances.

Cytoskeleton
• Is involve Microtubules,
intermediate filaments, and
microfilaments are three
protein fibers .
• In what they are involve are
involve ? establishing the
shape or movements of the
internal structure of the cell.

Lecture 6

The objective :
To understand the nucleus structure and function

Nucleus
Is centrally located and spherical or oval cellular component
which controls all the vital activities of the cell and carries the
hereditary material the DNA in it.

The nucleus consists of the following three structures
1. Chromatin
2. Nuclear envelope
3. Nucleolus

Chromatin
• Are condense form of chromosomes in non dividing cells .
And it either :
a. Euchromatin is the well-dispersed form of chromatin which
takes lighter DNA-stain and is genetically active (slightly
condense)
b. Heterochromatin is the highly condensed form of
chromatin which takes dark DNA-stain and is genetically
inert.

Nuclear envelope
• The nuclear envelope separates the nucleus from the rest of
the cell.
• It s consist two nuclear membranes
Inner nuclear membrane
Outer nuclear membrane which is continuous with rough ER.
• At certain points the nuclear envelope is interrupted by
structures called pores or nucleopores.

• Nucleopores
Nuclear pores regulate exchange between the nucleusand cytoplasm, number
of nucleoporesis found to be correlated with the transcriptionalactivity of the
cell
• Nucleoplasm
Is the glutinous substancewithin the nuclearenvelopealso it called
karyoplasm composed of ( water, salts, enzymes and many otherorganic
martials )
Is rich in those moleculeswhich are needed for DNA replication,
transcription, regulation of gene actions .

Nucleolus
• Nucleus contains in its nucleoplasm a conspicuous, darkly
stained, circular suborganelle, called nucleolus. Nucleolus
lacks any limiting membrane and is formed during interphase.
• Nucleolus is the site where ribosomes are manufactured

Lecture 7

The objective :
To understand the cell cycle and cell division

Cell cycle
• Each cell passes through a series of defind stages which called
cell cycle each cycle dived into two phases
M phase which is include the process of
I. mitosis in which duplicated chromosomes into two nuclei
II. Cytokinesis
During which the entire cell divide into two daughter cells.
Inter phase the period between cells divisions.

72
Types of Cell Reproduction
 Asexual reproduction involves a single cell dividing to make 2
new, identical daughter cells
 Mitosis & binary fission are examples of asexual reproduction
 Sexual reproduction involves two cells (egg & sperm) joining
to make a new cell (zygote) that is NOT identical to the
original cells
 Meiosis is an example

Mitosis
The process of cell division which results in the production of two
daughter cells from a single parent cell.
The daughter cells are identical to one another and to the
original parent cell.
Mitosis can be divided into stages

• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase & Cytokinesis

Interphase
The cell prepares for division
– DNA replicated
– Organelles replicated
– Cell increases in size

Interphase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Prophase
The cell prepares for nuclear division
– Packages DNA into
chromosomes

Prophase

Metaphase
The cell prepares chromosomes for division
– Chromosomes line up at
the center of the cell
– Spindle fibers attach from
daughter cells to
chromosomes at the
centromere

Metaphase

Anaphase
The chromosomes divide
– Spindle fibers pull
chromosomes apart
– ½ of each chromosome
(called chromotid)
moves to each
daughter cell

Anaphase

Telophase
The cytoplasm divides
– DNA spreads out
– 2 nuclei form
– Cell wall or cell
membrane pinches in to
form the 2 new daughter
cells

Telophase

Animal Mitosis -- Review
Interphase Prophase
Metaphase Anaphase
Telophase Interphase

Plant Mitosis -- Review
Interphase Prophase
Metaphase Anaphase
Telophase Interphase

Meiosis
Meiosis is the type of cell division by which germ cells (eggs and sperm)
are produced.
One parent cell produces four daughter cells.
Daughter cells have half the number of chromosomes found in the
original parent cell
.
twice
, but the nucleus divides
once
During meiosis, DNA replicates

Meiosis
Four stages can be described for each division of the
nucleus.

Meiosis I
First division of meiosis

First Division of Meiosis
• Prophase 1: Each chromosome duplicates and remains closely
associated. These are called sister chromatids.
• Metaphase 1: Chromosomes align at the center of the cell.
• Anaphase 1: Chromosome pairs separate with sister chromatids
remaining together.
• Telophase 1: Two daughter cells are formed with each daughter
containing only one chromosome of the chromosome pair.

Prophase I
http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html

Metaphase I

Telophase I

Meiosis
Second Division of Meiosis

Second Division of Meiosis
• Prophase 2: DNA does not replicate.
• Metaphase 2: Chromosomes line up at the center of the cell
• Anaphase 2: Centromeres divide and sister chromatids move
separately to each pole.
• Telophase 2: Cell division is complete.
Four haploid daughter cells are formed.

Prophase II

Metaphase II

Telophase II

Differences in Mitosis & Meiosis
• Mitosis
– Asexual
– Cell divides once
– Two daughter cells
– Genetic information
is identical
• Meiosis
– Sexual
– Cell divides twice
– Four haploid daughter
cells
– Genetic information is
different

END
Thanks

CELL(PLASMA ) MEMBRANE
Lecture 8

Our objective :
To know the plasma membrane structure and
function

Cell membrane
• plasma membrane separates the cytoplasmic contents of the
cell (the intracellular fluid) from the fluid outside the cell (
extracellular fluid).

Structure of plasma membrane
• The major components of the plasma membrane include:
 Lipids
 Carbohydrates
 Proteins

Lipids
• The basic structure of the plasma membrane is formed by
lipids which are one of the more abundant of the membrane
components.
• Lipids are amphipathic molecules that have polar (water-
soluble) and nonpolar (water-insoluble) regions.

They are three main types of membrane lipids
Phosphoglycerides
Sphingolipids
Cholesterol

Phosphoglycerides
Most membrane lipids contain a phosphate group.
Most phospholipids are built on a glycerol backbone hence they
are called phosphoglycerides
Sphingolipids
Less abundant class of membrane lipids derivative of sphingosine
( amino alcohol).
Cholesterol
Found in animal cells and absent from most plants and bacterial
cells.

Carbohydrates
• The plasma membrane of eukaryotic cell contain carbohydrate
that are liked to both proteins and lipids .
• Depending on the species and cell type , the carbohydrate
range between (2__10)%.
• More than 90% of membrane carbohydrate linked to protein to
form (glycoprotein), the remaining is linked to lipids to form
(glycolipid).

Proteins
• The plasma membrane contain hundreds of different proteins
which can be grouped into three distinct classes depending on
their relationship to lipid bilayer.

Integral protein:
• Penetrate the lipid bilayer , are transmembrane protein
Peripheral protein:
• Located entirely outside of the lipid bilayer on cytoplasmic or
extracellular side . They associated with surface of the
membrane.
Lipid –anchor protein :
• Located out side the lipid bilayer on either cytoplasm or
extracellular surface .

Functions of plasma membrane

Compartmentalization
• The plasma membrane enclose the content of the entire cell,
whereas the nuclear and cytoplasmic diverse intracellular
space .
• Membrane compartmentalization allows specialized activities
To proceed without external interference and enable cellular
activities to be regulated indepently to one another.

Scaffold for biochemical activities
• Plasma membrane provide the cell with an extensive
framework or scaffolding within which the components can be
ordered.

Providing a selectively permeable barrier
• Plasma membrane which encircle a cell serve as general
barrier with gates (bridges )to promote the movement of select
elements into and out of the cell.

Transportation solute
• The plasma membrane contain the machinery For physical
transporting substance from one side to another . Often from a
region where he solute is present at low concentration into
region where that the solute is present at higher concentration
which is called OSMOSIS.
• Plasma membrane is also able to transport specific ions .

Intercellular interaction
• Plasma membrane of multicellular organisms mediates the
interaction between a cell and its neighbor.
• Also allow cell to recognize and signal one another to
exchange martials and information.

Responding to external signals
• Plasma membrane play critical role in process known signal
transduction which is the response to external signals
(stimuli).
• Membrane possess receptor that combine with specific
molecules (ligands) having complementary structure.

Energy transduction
• Energy transduction is the process one type of energy is
convert to another type .
• The most fundamental energy transduction occur during
photosynthesis when energy in sunlight is absorbed by
membrane bound pigments convert into chemical energy .

The end of ours lectures
Thanks and good luck

Cell biology

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Cell biology

Similar to Cell biology (20)

Recently uploaded

Recently uploaded (20)

Cell biology