Transcript Zoology 106 course

Zoology 106 course
General Animal Biology
For Premedical Student
By Dr. Ashraf M. Ahmed
1429-1430H
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Questions Considered
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Why do certain reactions occur?
Why do others not occur?
What drives these processes?
Why do organic molecules have certain
properties?
• Can we predict the presence or absence
of certain properties?
• Can we make new materials with other
desired properties?
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Roles
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My role
Professor
Guide
Your Role
Student
Understand the material!
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Homework
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Every problem in the Text is assigned.
However,
They will not be graded.
They will not be collected.
They will not be discussed in class.
They are available to you to determine if
you understand the material.
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Attendance
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Assumption: you are adult students
Attendance in lecture is expected
Attendance at tests is expected.
A missed examination will receive a zero.
No excuses will be accepted.
A missed final exam will receive a zero.
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A Word on the Final Exam
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Communication in Class
• During my class you should
• Turn your cell phone off.
• Turn your desire to communicate with
anyone but me off.
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Expectations
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A professional student is expected to
attend class
purchase course materials
study
do the homework
be prepared for class
be prepared for tests
do well
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Doing Well
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Read the chapter before lecture
Attend lecture
Take notes
Do not rely on copies of Power Points
Re-read the chapter after lecture
Review lecture notes daily
Rewriting the lecture notes is strongly suggested
Keep, maintain, and study note cards
Do homework problems.
Form a study group
Learn the functional groups
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Good Luck
Dr. Ahmed Abdel.Zaher
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Types
The
Cell
Cellulae (Small room)
of cells
The Organism’s Basic Unit of Structure and Function
‫متقدمة‬
‫بدائية‬
Prokaryotic
Micro-organisms
‫الكائنات الدقيقة‬
Eukaryotic
All other forms
of life
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Cell Theory
1- All organisms are composed of one or
more of cells.
2- Cell is the basic unit of life.
3- The new cell arises only from preexisting cell.
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1). Prokaryotic and eukaryotic cells
differ in size and complexity
Similarities ‫أوجه التشابه‬
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All cells are surrounded by a plasma membrane ‫غشاء بالزمى‬.
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The semi-fluid substance ‫ المادة النصف سائلة‬within the cell is called
“cytosol”, ‫ السيتوبالزم‬containing the cell organelles ‫ ِعضيات الخلية‬.
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All cells contain chromosomes which have genes in the form of DNA.
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All cells have tiny organelles ‫ عضيات صغيرة‬called “Ribosomes” that
make proteins.
Page 112
1). Prokaryotic and eukaryotic cells
differ in size and complexity
Differences ‫أوجه اإلختالف‬
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A major difference ‫ الفرق األساسى‬between prokaryotic and
eukaryotic cells is the location of chromosomes ‫موضع الصبغيات‬.
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In an eukaryotic cell, chromosomes are contained in a true nucleus (‫) النواة‬.
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In a prokaryotic cell, the DNA is concentrated in the nucleoid (‫)شـبه نواة‬
without a membrane (‫ ) بدون غـشاء‬separating it from the rest of the cell.
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In prokaryotic cell, DNA is a single strand (‫ )أحادى الشريط‬or double strand
(‫ )ثنائى الشريط‬DNA. But in eukaryotic cell, DNA is double strand.
Page 112
‫‪(A)- Prokaryotes‬‬
‫الكائنات وحيدة الخلية ذات النواة البدائية‬
‫األحياء الدقيقة ‪Micro-organisms‬‬
‫‪Page 112, 526‬‬
Types of Prokaryotes
Prokaryotes
Bacteria
- Exist in most
environments
Archaea
- Exist in extreme environments
‫( البيئات القاسية‬hot and salty)
They are differing in some other structural, biochemical
and physiological characteristics ‫صفات‬
Page 526
Prokaryotes
1- Bacteria
‫شبه نواة‬
‫الريبوزومات‬
‫غشاء بالزمى‬
‫الجدار الخلوى‬
‫الكبسولة‬
‫األسواط‬
Fig. 7.4 The prokaryotic cell is much simpler in structure, lacking a nucleus
and the other membrane-enclosed organelles of the eukaryotic cell.
Page 112
Prokaryotic Cell
Plasma
membrane
Ribosomes
Nucleoid
Cell Wall
Cytoplasm
(Cytosol)
Capsule
A) the bacterial capsule
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Many prokaryotes (bacteria)
secrete a sticky
protective layer called
capsule outside
the cell wall, which has the
following functions ‫وظائف‬:
1.
2.
3.
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Adhere ‫ تثبيت‬bacteria cells to their substratum ‫السطح‬.
Increase bacteria resistance ‫ المقاومة‬to host defenses ‫مناعة العائل‬.
Stick )‫ )تلصق‬bacterial cells together when live as colonies.
Protect ‫ تحمى‬bacterial cell.
Fig. 27.6
B) The bacterial cell wall
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In all prokaryotes, the functions of the cell wall are as
following:
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maintains ‫ تحافط‬the shape of the cell,
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affords physical protection ‫توفر الحماية الطبيعية‬
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prevents the cell from bursting (‫ )إنفجار‬in a hypotonic
environment ‫البيئة ذات الضغط األسموزى المنخفض‬.
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Most bacterial cell walls contain peptidoglycan
(a polymer of modified sugars cross-linked by short polypeptides).
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The walls of Archaea lack (‫ )تـفـتـقـد‬peptidoglycan.
The Gram’s stain: ‫صبغة جرام‬
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It is a tool for identifying ‫ تعريف‬specific bacteria, based on
differences in their cell walls.
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A)- Gram-positive (Gram +ve) bacteria:
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Their cell walls have large amounts ‫ كمية كبيرة‬of peptidoglycans
that react with Gram’s stain (appear violet-stained ‫)تـُصبغ بنفسجيا‬.
Fig. 27.5a
Page 529
The Gram’s stain: ‫صبغة جرام‬
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B)- Gram-negative (Gram -ve) bacteria:
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their cell walls have no or small amount of
peptidoglycan. So, do not react or very weakly react with
Gram’s stain (do not appear stained ‫)ال تظهر الصبغة‬
Fig. 27.5b Page 529
Gram Staining of Bacteria
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Gram +ve bacteria: have Large amount of peptidoglycan
that stained violet (non-pathogenic ‫)غير ممرضة‬.
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Gram –ve bacteria: Have small amount or no peptidoglycan
(no staining) (pathogenic ‫)ممرضة‬.
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Gram-negative species are pathogenic (‫ ) ممرضة‬more threatening
(‫ )أكثر خطورة‬than gram-positive species.
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Gram-negative bacteria are commonly more resistant (‫)أكثر ممانعة‬
than gram-positive species to antibiotics ‫للمضادات الحياتية‬.
Reproduction of Bacteria
‫التكاثر فى البكتريا‬
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Prokaryotes reproduce (‫ )تـتـكاثر‬only asexually (‫)ال جنسيا‬
by binary fission (‫)اإلنقسـام الثـنائى البسيط‬.
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A single cell produce
a colony of offspring.
Fig. 27.9 Page 531 Mov
Nutrition of Prokaryotes
‫التغذية فى األحياء الدقيقة‬
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Nutrition refers to how an organism obtains
energy and a carbon source from the environment
to build the organic molecules of its cells.
• Prokaryotes are grouped (‫صنٍفـَت‬
ُ ) into four
categories (‫ )أنواع‬according to how they obtain
energy and carbon
Nutrition of Prokaryotes
‫التغذية فى األحياء الدقيقة‬
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Phototrophs (‫)ضوئية التغذية‬:
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Chemotrophs (‫)كيميائية التغذية‬:
Organisms that obtain energy from light.
Organisms that obtain energy from
chemicals in their environment.
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Autotrophs (‫)ذاتية التغذية‬:
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Heterotrophs (‫)متعدد التغذية‬:
a carbon source.
Organisms that use CO2 as a carbon source.
Organisms that use organic nutrients as
There are four major modes of nutrition
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Photoautotrophs (‫)ذاتية التغذية الضوئية‬:
use light energy as energy source, and CO2 as carbon source to synthesis
(‫ )تخلق‬organic compounds.
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Chemoautotrophs )‫)ذاتية التغذية الكيميائية‬:
use chemical inorganic substances as energy source, and CO2 as a carbon
source.
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Photoheterotrophs (‫)متعدد التغذية الضوئية‬:
use light as energy source, and organic substances as carbon source.
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Chemoheterotrophs (‫)متعدد التغذية الكيميائية‬:
use organic substances as a source for both energy and carbon.
Prokaryotic modes of nutrition
Based on Carbon source and Energy source that can be used
by a prokaryote organism to synthesise organic compounds.
Prokaryotes
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Autotrophs
CO2 as Carbon Source
Photoautotroph
Chemoautotroph
Heterotrophs
Organic compounds as
Carbon ( C) Source
PhotoHeterotroph
ChemoHeterotroph
- Light as energy
source
- Chemicals as
energy source
- Light as
energy source
- Chemicals as
energy source
-CO2 as C source
-CO2 as C source
-Organic
compounds as
C source
- Organic
compounds as C
source