Cell Biology 2013 Course (2)

7/29/2019 Cell Biology 2013 Course (2)

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Cell Biology CourseDepartment of Biochemistry

Semester (1)


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12 weeks

Practical 2 hrs 25 marks

Theoretical 1 hr 65 marks

Dr Ahmed Salah Ibrahim (6 hrs)

Cell theory and cell structure Cell signalling and communication

Prof. Dr. Liala Eissa (6 hrs) Cell Cycle

Apoptosis


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:

25%


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BIOLOGY

=__________________= ________________

Study of living things

Bacteria

The science of LIFE


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Creatures or Organisms?

The term creature implies a Creator!

So, it is best to call them creatures.

Modern textbook authors that deny God do notlike to use the term creature.


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What are the characteristics of living things?

What does it mean to be living?

People, plant, and animals are all alive; stones,

sand, and wind are not.

But what are the fundamental

properties that characterize living things anddistinguish them from nonliving matter?


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The answer begins with a basic fact that All living things are

made of cells: small, membrane enclosed units filled with a

concentrated aqueous solution of chemicals and has the

ability to create copies of themselves

by growing and dividing.

The simplest forms of life is the cell.


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9

Intro into Cell Biology

-> All living organismsare made out of cells

-> Cells are thesmallest living unit

Human egg cell + sperm


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(Cell)(Robert Hooke)

:

cell Theory:

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.10(10,000,000,000,000).

..

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.


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Cell Theory

Schleiden and Schwann proposed thecell theory in 1838, sine then cell

biology research was forever changed.

The cell theory states that:

1-All life forms are made from one or

more cells.

2-Cells only arise from pre-existing cells.3-The cell is the smallest form of life.


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Cells are divided into two main classes,initially defined by whether theycontain a nucleus:

1-Prokaryotic cells (bacteria) lack anuclear envelope

2-Eukaryotic cells have a nucleus inwhich the genetic material isseparated from the cytoplasm.


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Prokaryotic cells are generally smaller and

simpler than eukaryotic cells; in addition to

the absence of a nucleus, their genomes areless complex and they do not contain

cytoplasmic organelles or a cytoskeleton


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14

Intro into Cell Biology

Cell Types


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Cell biology:


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cell biology

is the sciences that study all life processes within cells..

Understanding the cell biology is important for manyapplications in medicine, agriculture, biotechnology, andbiomedical engineering.

Striking examples include the development of new drugsspecifically targeted to interfere with the growth ofcancer cells.


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Biochemistry & Biophysics: study of the

structures and behaviors of molecules


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Microbiology: study of prokaryotic cells and

viruses


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Cell Biology: study of the structure and

function of eukaryotic cells


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Developmental Biology: study of how communities

of cells form tissues, organs, and build an

organism


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Anatomy & Physiology: study of the structures

and functions of tissues and organs


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Zoology & Plant Biology: study of the

organisms


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Ecology: study of how organisms interact

with each other and with their environments


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Levels of Biological Complexity

.1Biochemistry & Biophysics

.2Microbiology

.3Cell Biology

.4Developmental Biology

.5Anatomy & Physiology

.6Zoology & Plant Biology

.7Ecology


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Tools for studying Cell Biology

Research in cell biology depends on the

laboratory methods that can be used

to study cell structure and function

1- Microscopy methods

2- Biochemistry and molecular biology

methods

S i 2 Di i C ll


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Section 2: Discovering Cells

Microscope = makes small objects appear larger.

The first cell sightings were possible because of theinvention of the microscope.

* An Electron Microscope = does not use light, but

uses a beam of electrons instead. Light Microscope:

- Convex lens = a lens with a curved shape

- Magnification = how large image appears under the

scope. - Resolution = is how clear or sharp the image is.

CompoundLightMicroscope = a light microscope

with more than one lens.


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Light Microscopy

Robert Hooke first coined the term "cell" following his observations of apiece of cork with a simple light microscope in 1665

Using a microscope that magnified objects up to about 300 times theiractual size was able to observe a variety of different types of cells,including sperm, red blood cells, and bacteria.

Current light microscopes are able to magnify objects up to about athousand times.

Since most cells are between 1 and 100 pm in diameter, they can beobserved by light microscopy, as can some of the larger subcellularorganelles, such as nuclei, chloroplasts, and mitochondria

However, the light microscope is not sufficiently powerful to reveal finedetails of cell structure due to limited resolution


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Hookes Microscope


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The cellular structure of cork as

observed by Hooke


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Fluorescence microscopy

It is very sensitive method for studying theintracellular distribution of molecules

A fluorescent dye is used to label themolecule of interest within either fixed orliving cells. The fluorescent dye is a moleculethat absorbs light at one wavelength andemits light at a second wavelength.

An important recent advance in fluorescencemicroscopy has been the

use of the green fluorescent protein (GFP) ofjellyfish to visualize proteins within livingcells.


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Fluorescence microscopy of a protein labeled with GFP A microtubule-

associated protein fused to GFP was introduced into mouse neurons in

culture and visualized by fluorescence microscopy. Nuclei are stained

blue


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Electron Microscope

The electron microscope can achieve a much

greater resolution than that obtained with

the light microscope because the

wavelength of electrons is shorter than thatof light.

There are two types of Electron microscope:

1- Transmission Electron microscopes

2- Scanning Electron microscopes
http://en.wikipedia.org/wiki/File:Electron_Microscope.jpg


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http://en.wikipedia.org/wiki/File:Electron_Microscope.jpg


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Transmission electron microscopy (TEM) involves a high voltage electron

beam. The electron beam that has been partially transmitted through the

very thin specimen carries information about the structure of the specimen.

Transmission electron microscopes produce two-dimensional, black andwhite images.

Unlike the TEM, where the electrons in the primary beam are transmitted through the

sample, the Scanning Electron Microscope (SEM) produces images by detectingsecondary electrons which are emitted from the surface due to excitation by the

primary electron beam. In the SEM, the electron beam is scanned across the surface of

the sample, with detectors building up an image by mapping the detected signals with

beam position.

Because the SEM image relies on electron interactions at the surface rather thantransmission it is able to image bulk samples and has a much greater depth of view,

and so can produce images that are a good representation of the 3D structure of the

sample.


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Cell Biology 2013 Course (2)

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