chapter 1 introduction to cell biology © 2013 john wiley & sons, inc. all rights reserved

CHAPTER 1

Introduction to Cell Biology

© 2013 John Wiley & Sons, Inc. All rights reserved.

What is Biology?Biology literally means "the study of "the study of life"life". Biology is such a broad field, covering the minute workings of chemical machines inside our cells, to broad scale concepts of ecosystems and global climate change.

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Branches of Biology•Anatomy - the study of form and function, in plants, animals, and other organisms, or specifically in humans •Biochemistry - the study of the chemical reactions required for life to exist and function, usually a focus on the cellular level •Botany - the study of plants •Cell biology - the study of the cell as a complete unit, and the molecular and chemical interactions that occur within a living cell. •Ecology - the study of the interactions of living organisms with one another and with the non-living elements of their

environment. •Embryology - the study of the development of embryo (from fecondation to birth). See also topobiology. •Entomology - the study of insects

•Physiology - the study of the functioning of living organisms and the organs and parts of living organisms• Genetics - the study of genes and heredity. •Histology - the study of cells and tissues, a microscopic branch of anatomy. •Microbiology - the study of microscopic organisms (microorganisms) and their interactions with other living things •Molecular Biology - the study of biology and biological functions at the molecular level, some cross over with biochemistry •Virology - the study of viruses and some other virus-like agents •Zoology - the study of animals, including classification, physiology, development, and behavior.

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Sizes of cells and organelles (105, 107)Bacteria 1 –5 m

Animal and Plant cells10-50 m

Nucleus 5-6 m Mitochondria 2-3 m Chloroplasts 5-10 m

Nerve cells > 1 m

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Feeling of scales

Cell

Size

rangeMost Cells

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What Is Life?Basic life processes (31)

o Metabolismo Movemento Responsivenesso Homeostasis o Differentiation Reproduction and heredity Growth and development

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The Cell Theory : (91)is one of the foundations of modern biology. It

stats that :

•All living things are composed of one or more cells;

•The chemical reactions of living cells take place within cells;

•All cells originate from pre-existing cells; and

•Cells contain hereditary information, which is passed from one generation to another

• The discovery of cells followed from the invention of the microscope by Robert Hooke, and its refinement by Anton Leewenhoek.

• Cell theory was articulated in the mid-1800s by Schleiden, Schwann and Virchow.– All organisms are composed or one or more cell.– The cell is the structural unit of life.– Cells arise from pre-existing cells by division.

Leewenhoek: single lens microscope

Hooke: double lens microscope

(1.1) The Discovery of Cells (90)

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(1.2) Basic Properties of Cells (91)

• Life is the most basic property of cells.

• Cells can grow and reproduce in culture for extended periods.

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Basic Properties of Cells

1- Cells Are Highly Complex and Organized– Cellular processes are highly regulated.– Cells from different species share

similar structure, composition and metabolic features that have been conserved throughout evolution.

Levels of cellular and molecular organization

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Organization in living organisms (28-30)• Atoms:

– are the smallest chemical units • Molecules:

– are a group of atoms working together• Organelles:

– are a group of molecules working together• Cells:

– are a group of organelles working together• Tissues:

– are a group of similar cells working together• Organs:

– are a group of different tissues working together

• Organ systems: – are a group of organs working together

• Organism: – is an individual© 2013 John Wiley & Sons, Inc. All rights reserved.

Basic Properties of Cells

2- Cells Possess a Genetic Program and the Means to Use It– Genes encode information to build

each cell, and the organism.– Genes encode information for

cellular reproduction, activity, and structure.

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Levels of cellular and molecular organization

Basic Properties of Cells

3- Cells Are Capable of Producing More of Themselves– Cells reproduce, and

each daughter cells receives a complete set of genetic instructions.

Mammalian oocyte after unequal cell division to produce polar body (arrow)

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Basic Properties of Cells

4- Cells Acquire and Utilize Energy– Photosynthesis provides fuel for all living organisms.– Animal cells derive energy from the products of photosynthesis,

mainly in the form of glucose.– Cell can convert glucose into ATP—a substance with readily available

energy.

© 2013 John Wiley & Sons, Inc. All rights reserved.

Basic Properties of Cells

5- Cells Carry Out a Variety of Chemical Reactions

6- Cells Engage in Mechanical Activities

7- Cells Are Able to Respond to Stimuli

8- Cells Are Capable of Self-Regulation

9- Cells EvolveSpirogyra: alga with ribbon-like chloroplast for photosynthesis

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Cells: the basic unit of life

(99).

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The CellThe CellThe CellThe CellThe Organism’s Basic Unit of Structure and Function

ProkaryoticProkaryoticProkaryoticProkaryotic EukaryoticEukaryoticEukaryoticEukaryotic

TypesTypes of cellsof cells

Micro-organisms All other forms of life

Cellulae (Small room)

بدائية

الكائنات الدقيقة

متقدمة

ProkaryotesProkaryotes

BacteriaBacteriaBacteriaBacteria ArchaeaArchaeaArchaeaArchaea

- Exist in extreme environments - Exist in extreme environments القاسية القاسية البيئات (hot and salty) (hot and salty) البيئات

- Exist in most - Exist in most environments environments

They are differing in some other They are differing in some other structuralstructural,, biochemical biochemical andand physiological physiological characteristics characteristics صفاتصفات

Types of ProkaryotesTypes of Prokaryotes

Page 526

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النواة بدائية الخاليا تركيبProkaryotes

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Typical prokaryotic structures

Working from the outside in…

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Generalized Prokaryote

CapsuleCapsule

Cell WallCell WallPlasmaPlasmaMembraneMembrane

CytosolCytosol

Nucleoid DNANucleoid DNA

FlagellumFlagellum

Plasmid DNAPlasmid DNA

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Typical shapes of bacteria

Most bacteria retain a particular shape; a feware pleiomorphic

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Characteristic grouping (or not grouping)

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Bacterial Shape and Arrangement

• Many prokaryotes (bacteria) Many prokaryotes (bacteria) secrete a sticky protective layer secrete a sticky protective layer called called capsulecapsule outside outside the cell wall, which has the the cell wall, which has the following functions following functions وظائفوظائف::

Adhere Adhere تثبيت bacteria cells to their substratum bacteria cells to their substratum السطح.. Increase bacteria resistance Increase bacteria resistance المقاومة to host defenses to host defenses العائل ..مناعة StickStickتلصقتلصق)) ) ) bacterial bacterial cells cells togethertogether when live as colonies.when live as colonies. Protect Protect تحمى bacterial cell.bacterial cell.

Fig. 27.6

A) the bacterial capsuleA) the bacterial capsule

• In all prokaryotes, the functions of the cell wall are as following:

1. maintains تحافطتحافط the shape of the cell,

2. affords physical protection الطبيعية الطبيعية الحماية توفرتوفر الحماية

3. prevents the cell from bursting ((إنفجارإنفجار) ) in a hypotonic

environment المنخفض األسموزى الضغط ذات المنخفض البيئة األسموزى الضغط ذات .البيئة

• Most bacterial cell walls contain peptidoglycanpeptidoglycan

(a polymer of modified sugars cross-linked by short polypeptides).

• The walls of Archaea lack ((تـفـتـقـدتـفـتـقـد) ) peptidoglycan.

B) The bacterial cell wallB) The bacterial cell wall

• It is a tool for identifying تعريف specific bacteria, based on differences in their cell walls.

• A)- Gram-positive (A)- Gram-positive (Gram +veGram +ve) bacteria:) bacteria:

• Their cell walls have large amounts كمية كبيرة of peptidoglycans that react with Gram’s stain (appear violet-violet-stained تُـصبغ بنفسجياتُـصبغ بنفسجيا).

Fig. 27.5a Page 529

The Gram’s stain: The Gram’s stain: صبغة جرامصبغة جرام

• B)- Gram-negativeB)- Gram-negative (Gram -ve) bacteria:

• 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 الصبغةتظهر الصبغة

Fig. 27.5b Page 529

The Gram’s stain: The Gram’s stain: صبغة جرامصبغة جرام

Gram Staining of BacteriaGram Staining of Bacteria

• Gram +ve bacteria:Gram +ve bacteria: have Large amount of peptidoglycan that stained have Large amount of peptidoglycan that stained violet violet ((non-pathogenicnon-pathogenic غير ممرضةغير ممرضة))..

• Gram –ve bacteria:Gram –ve bacteria: Have small amount or no peptidoglycan (no Have small amount or no peptidoglycan (no staining) (staining) (pathogenicpathogenic ممرضةممرضة).).

Gram-negative species are pathogenic (Gram-negative species are pathogenic (ممرضةممرضة ) more threatening ) more threatening (( خطورة خطورة أكثر .than gram-positive species. ) than gram-positive species (أكثر

Gram-negative bacteria are commonly more resistant (Gram-negative bacteria are commonly more resistant ( ممانعة ممانعة أكثر ( (أكثرthan gram-positive species to antibiotics than gram-positive species to antibiotics الحياتية الحياتية للمضادات ..للمضادات

Prokaryotes reproduce (تـتـكاثر) only asexually (ال ) by binary fission (جنسيا البسيط الثـنائى .(اإلنقسـام

A single cell produce a colony of offspring.

Fig. 27.9 Page 531

Reproduction of Bacteria Reproduction of Bacteria البكتريا فى البكتريا التكاثر فى التكاثر

Nutrition of Prokaryotes Nutrition of Prokaryotes التغذية فى األحياء الدقيقة

• Prokaryotes are grouped Prokaryotes are grouped (6فَـت into four into four (ص8ٍن

categories categories (أنواع) according to how they according to how they

obtain energy and carbonobtain energy and carbon

Nutrition refers to how an organism obtains energy and a carbon source from the environment to build the organic molecules of its cells.

PhototrophsPhototrophs ( التغذية التغذية ضوئية Organisms that obtain energy from :(ضوئية

light.

ChemotrophsChemotrophs ( التغذية التغذية كيميائية Organisms that obtain energy :(كيميائية

from chemicals in their environment.

AutotrophsAutotrophs ( التغذية التغذية ذاتية Organisms that use CO2 as a carbon :(ذاتية

source.

HeterotrophsHeterotrophs ( التغذية التغذية متعدد Organisms that use organic :(متعدد

nutrients as a carbon source.

Nutrition of Prokaryotes Nutrition of Prokaryotes التغذية فى األحياء الدقيقة

PhotoautotrophsPhotoautotrophs (ذاتية التغذية الضوئية): use light energylight energy as energy source, and COCO2 2 as carbon source to synthesis (تخلق) organic compounds.

ChemoautotrophsChemoautotrophs ذاتية التغذية الكيميائية)): use chemical inorganic substancesinorganic substances as energy source, and COCO22 as a carbon source.

PhotoheterotrophsPhotoheterotrophs (متعدد التغذية الضوئية): use use lightlight as energy source, and organic substancesorganic substances as carbon source.

ChemoheterotrophsChemoheterotrophs (متعدد التغذية الكيميائية): use organic substancesorganic substances as a source for both energy and carbon.

There are four major modes of nutritionThere are four major modes of nutrition

Prokaryotic modes of nutritionProkaryotic modes of nutrition

Page 532Page 532

Based on Based on Carbon sourceCarbon source and and Energy sourceEnergy source that can be used that can be used by a prokaryote organism to synthesise organic compounds. by a prokaryote organism to synthesise organic compounds.

AutotrophsAutotrophs HeterotrophsHeterotrophs

Photo-Photo-autotrophautotroph

Chemo-Chemo-autotrophautotroph

Chemo-Chemo-HeterotrophHeterotroph

Photo-Photo-HeterotrophHeterotroph

COCO22 as Carbon Source as Carbon SourceOrganic compounds as Organic compounds as

Carbon SourceCarbon Source

- Light as energy - Light as energy source source

-CO-CO22 as C source as C source

- Chemicals as- Chemicals as energy source energy source

-CO-CO2 2 as C sourceas C source

- Light as- Light as energy source energy source

-Organic -Organic compounds as compounds as C sourceC source

- Chemicals as- Chemicals as energy source energy source

- Organic - Organic compounds as C compounds as C sourcesource

ProkaryotesProkaryotes

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Eu: True

Karyon: Nucleus

B- Eukaryotic CellB- Eukaryotic Cell

Animal CellAnimal Cell Plant CellPlant Cell

Page 114 - 115

Compare between Animal and Plant Compare between Animal and Plant cell?cell?

What are the functions of cell organelles What are the functions of cell organelles ??

38Fig. 7.7, Page 114

ميتوكوندريميتوكوندرياا

غشاء غشاء بالزمىبالزمى

حهاز حهاز جولـچـىجولـچـى

ريبوسوريبوسومم

الهيكل الهيكل الخلوىالخلوى

مhحلل مhحلل جسم جسم

جسم جسم مركزىمركزى

سوط سوط حركىحركى

الشبكة الشبكة اإلندوبالزميةاإلندوبالزمية

النواةالنواة

المادة المادة الوراثيةالوراثية

نويةنوية

الجدار الجدار النووىالنووى

حلمات حلمات دقيقةدقيقة

39Fig. 7.8, Page 115

فجوة فجوة مركزيةمركزية

بالستيدة بالستيدة خضراءخضراء

بينية بينية ثقوب ثقوب

الجدار الجدار الخلوىالخلوى

• All cells are surrounded by a All cells are surrounded by a plasma membrane plasma membrane غشاء بالزمىغشاء بالزمى..

• The semi-fluid substance The semi-fluid substance المادة النصف سائلةالمادة النصف سائلة within the cell is called within the cell is called

“cytosol”“cytosol”, , السيتوبالزمالسيتوبالزم containing the cell organelles containing the cell organelles ضيات الخليةmضيات الخليةعmع..

• All cells contain chromosomes which have genes in the form of DNA.All cells contain chromosomes which have genes in the form of DNA.

• All cells have tiny organelles All cells have tiny organelles عضيات صغيرةعضيات صغيرة called called ““Ribosomes”Ribosomes” that that

make proteins.make proteins.

1). 1). ProkaryoticProkaryotic and and eukaryoticeukaryotic cells cells differ in size and complexity differ in size and complexity

SimilaritiesSimilarities أوجه التشابهSimilaritiesSimilarities أوجه التشابه

Page 112

• A major difference A major difference الفرق األساسىالفرق األساسى between prokaryotic and between prokaryotic and

eukaryotic cells is the eukaryotic cells is the location of chromosomeslocation of chromosomes موضع موضع

..الصبغياتالصبغيات– In an eukaryotic cell, chromosomes are contained in a true In an eukaryotic cell, chromosomes are contained in a true nucleus nucleus

..(( النواةالنواة))

– In a prokaryotic cell, the DNA is concentrated in the In a prokaryotic cell, the DNA is concentrated in the nucleoidnucleoid (( نواة نواة شـبه ( (شـبه

without a membrane (without a membrane ( غـشاء غـشاء بدون .separating it from the rest of the cell. ) separating it from the rest of the cell (بدون

– In prokaryotic cell, DNA is a single strand (In prokaryotic cell, DNA is a single strand ( الشريط الشريط أحادى or double ) or double (أحادى

strand (strand ( الشريط الشريط ثنائى .DNA. But in eukaryotic cell, DNA is double strand.) DNA. But in eukaryotic cell, DNA is double strand (ثنائى

1). 1). ProkaryoticProkaryotic and and eukaryoticeukaryotic cells cells differ in size and complexity differ in size and complexity

DifferencesDifferences أوجه االختالف

Page 112

Basic Properties of Cells

• Characteristics that distinguish prokaryotic and eukaryotic cells– Complexity: Prokaryotes are relatively simple; eukaryotes are more complex

in structure and function.– Cytoplasm: Eukaryotes have membrane-bound organelles and complex

cytoskeletal proteins. Both have ribosomes but they differ in size.– Cellular reproduction: Eukaryotes divide by mitosis; prokaryotes divide by

simple fission.– Locomotion: Eukaryotes use both cytoplasmic movement, and cilia and

flagella; prokaryotes have flagella, but they differ in both form and mechanism.

– Genetic material:• Packaging: Prokaryotes have a nucleoid region whereas eukaryotes have a

membrane-bound nucleus.• Amount: Eukaryotes have much more genetic material than prokaryotes.• Form: Eukaryotes have many chromosomes made of both DNA and protein

whereas prokaryotes have a single, circular DNA.

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Bacterium

The structure of cells (96)

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The structure of cells

Plant cell

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Animal cell

The structure of cells (97)

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Cellular reproduction: Eukaryotes and prokaryotes (100-101)

Cell division in eukaryotesDNA (blue) and microtubules (green) of two daughter cells.

Bacterial conjugationSharing of DNA through

the F pilus

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Pathways of cell differentiation

• Types of Eukaryotic Cells: Cell Specialization– Multicellular eukaryotes

have different cell types for different functions.

• Differentiation occurs during embryonic development in other multicellular organisms.

• Numbers and arrangements of organelles relate to the function of the cell.

• Despite differentiation, cells have many features in common.

Basic Properties of Cells (104)

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Classifications of Tissues1. Epithelium:

lines and covers surfaces

2. Connective tissue: protect, support, and bind together

3. Muscular tissue: produces movement

4. Nervous tissue: receive stimuli and conduct impulses

Epithelium - Shapes:

• Squamous: flat,thin, scale-like cells

• Cuboidal:cells that have a basic cube shape. Typically the cell's height and width are about equal.

• Columnar: tall, rectangular or column shaped cells. Typically taller than they are wide.

Epithelium - Arrangements:

• Simple: Cells are found in a single layer attached to the basement membrane

• Stratified: Cells are found in 2 or more layers stacked atop each other

• Pseudostratified: a single layer of cells that appears to be multiple layers due to variance in height and location of the nuclei in the cells.

• Transitional: cells are rounded and can slide across one another to allow stretching

Connective• 1. Connective tissue proper

– a. Loose Connective Tissue• i. Areolar• ii. Adipose• iii. Reticular

– b. Dense Connective Tissue• i. Dense regular• ii. Dense irregular• iii. Elastic

• 2. Cartilage– a. Hyaline– b. Elastic– c. Fibrocartilage

• 3. Bone (osseous tissue)• 4. Blood