CHAPTER 1 Introduction to Cell Biology © 2013 John Wiley & Sons, Inc. All rights reserved.

What is Biology? "the study of life" Biology literally means "the study of 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.

3 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 plantsBotany 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.Ecology Embryology - the study of the development of embryo (from fecondation to birth). See also topobiology.Embryology Entomology - the study of insectsEntomology

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.Zoology

5 Sizes of cells and organelles (105, 107) Bacteria 1 – 5  m Animal and Plant cells  m Nucleus5-6  m Mitochondria2-3  m Chloroplasts5-10  m Nerve cells> 1 m

6 Feeling of scales Cell Size range Most Cells

7 What Is Life? Basic life processes (31) o Metabolism o Movement o Responsiveness o Homeostasis o Differentiation Reproduction and heredity Growth and development

© 2013 John Wiley & Sons, Inc. All rights reserved. The Cell Theory : (91)Cell Theory 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) © 2013 John Wiley & Sons, Inc. All rights reserved.

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

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

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

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 Evolve Spirogyra: alga with ribbon-like chloroplast for photosynthesis © 2013 John Wiley & Sons, Inc. All rights reserved.

17 Cells: the basic unit of life

(99).

19 The Cell The Organism’s Basic Unit of Structure and Function ProkaryoticProkaryotic EukaryoticEukaryotic Types of cells of cells Micro-organisms All other forms of life Cellulae (Small room) بدائية الكائنات الدقيقة متقدمة

Prokaryotes BacteriaBacteriaArchaeaArchaea - Exist in extreme environments البيئات القاسية (hot and salty) - Exist in most environments They are differing in some other structural, biochemical and physiological characteristics صفات Types of Prokaryotes Page 526

21 تركيب الخلايا بدائية النواة Prokaryotes

22 Typical prokaryotic structures Working from the outside in…

23 Generalized Prokaryote Capsule Cell Wall Plasma Membrane Cytosol Nucleoid DNA Flagellum Plasmid DNA

24 Typical shapes of bacteria Most bacteria retain a particular shape; a few are pleiomorphic

25 Characteristic grouping (or not grouping)

26 Bacterial Shape and Arrangement

Many prokaryotes (bacteria) secrete a sticky protective layer called capsule outside the cell wall, which has the following functions وظائف : Many prokaryotes (bacteria) secrete a sticky protective layer called capsule outside the cell wall, which has the following functions وظائف : 1.Adhere bacteria cells to their substratum. 1.Adhere تثبيت bacteria cells to their substratum السطح. 2.Increase bacteria resistance to host defenses. 2.Increase bacteria resistance المقاومة to host defenses مناعة العائل. 3.Stick تلصق ) ) bacterial cells together when live as colonies. 4.Protect bacterial cell. 4.Protect تحمى bacterial cell. Fig A) the bacterial capsule

In all prokaryotes, the functions of the cell wall are as following: تحافط 1.maintains تحافط the shape of the cell, الحماية الطبيعية توفر 2.affords physical protection الحماية الطبيعية توفر ( إنفجار ) البيئة ذات الضغط الأسموزى المنخفض 3.prevents the cell from bursting ( إنفجار ) in a hypotonic environment البيئة ذات الضغط الأسموزى المنخفض. peptidoglycan Most bacterial cell walls contain peptidoglycan ( a polymer of modified sugars cross-linked by short polypeptides ). ( تـفـتـقـد ) The walls of Archaea lack ( تـفـتـقـد ) peptidoglycan. B) The bacterial cell wall

It is a tool for identifying تعريف specific bacteria, based on differences in their cell walls. A)- Gram-positive ( Gram +ve ) bacteria: A)- Gram-positive ( Gram +ve ) bacteria: violet- تـُصبغ بنفسجيا Their cell walls have large amounts كمية كبيرة of peptidoglycans that react with Gram’s stain (appear violet- stained تـُصبغ بنفسجيا ). Fig. 27.5a Page 529 The Gram’s stain: صبغة جرام

B)- Gram-negative B)- Gram-negative ( Gram -ve ) bacteria: تظهر الصبغة 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 لا تظهر الصبغة ) Fig. 27.5b Page 529 The Gram’s stain: صبغة جرام

Gram Staining of Bacteria Gram +ve bacteria: have Large amount of peptidoglycan that stained violet ( non-pathogenic غير ممرضة ). Gram +ve bacteria: have Large amount of peptidoglycan that stained violet ( non-pathogenic غير ممرضة ). Gram –ve bacteria: Have small amount or no peptidoglycan (no staining) ( pathogenic ممرضة ). Gram –ve bacteria: Have small amount or no peptidoglycan (no staining) ( pathogenic ممرضة ). Gram-negative species are pathogenic ( ممرضة ) more threatening ( أكثر خطورة ) than gram-positive species. Gram-negative species are pathogenic ( ممرضة ) more threatening ( أكثر خطورة ) than gram-positive species. Gram-negative bacteria are commonly more resistant ( أكثر ممانعة ) than gram-positive species to antibiotics للمضادات الحياتية. Gram-negative bacteria are commonly more resistant ( أكثر ممانعة ) than gram-positive species to antibiotics للمضادات الحياتية.

Prokaryotes reproduce ( تـتـكاثر ) only asexually ( لا جنسيا ) by binary fission ( الإنقسـام الثـنائى البسيط ). A single cell produce a colony of offspring. Fig Page 531 Reproduction of Bacteria التكاثر فى البكتريا

Nutrition of Prokaryotes Nutrition of Prokaryotes التغذية فى الأحياء الدقيقة Prokaryotes are grouped into four categories according to how they obtain energy and carbonProkaryotes are grouped (صُنٍفـَت) into four categories (أنواع) according to how they obtain 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.

Phototrophs ضوئية التغذية Phototrophs ( ضوئية التغذية ): Organisms that obtain energy from light. Chemotrophs كيميائية التغذية Chemotrophs ( كيميائية التغذية ): Organisms that obtain energy from chemicals in their environment. Autotrophs ذاتية التغذية Autotrophs ( ذاتية التغذية ): Organisms that use CO 2 as a carbon source. Heterotrophs متعدد التغذية Heterotrophs ( متعدد التغذية ): Organisms that use organic nutrients as a carbon source. Nutrition of Prokaryotes Nutrition of Prokaryotes التغذية فى الأحياء الدقيقة

 Photoautotrophs light energyCO 2  Photoautotrophs ( ذاتية التغذية الضوئية ): use light energy as energy source, and CO 2 as carbon source to synthesis ( تخلق ) organic compounds.  Chemoautotrophs inorganic substancesCO 2  Chemoautotrophs ذاتية التغذية الكيميائية )): use chemical inorganic substances as energy source, and CO 2 as a carbon source.  Photoheterotrophs use light organic substances  Photoheterotrophs ( متعدد التغذية الضوئية ): use light as energy source, and organic substances as carbon source.  Chemoheterotrophs  Chemoheterotrophs ( متعدد التغذية الكيميائية ): organic substances use organic substances as a source for both energy and carbon. There are four major modes of nutrition

Prokaryotic modes of nutrition Page 532 Based on Carbon source and Energy source that can be used by a prokaryote organism to synthesise organic compounds. AutotrophsHeterotrophs Photo- autotroph Chemo- autotroph Chemo- Heterotroph Photo- Heterotroph CO 2 as Carbon Source Organic compounds as Carbon Source - Light as energy source -CO 2 as C source - Chemicals as energy source -CO 2 as C source - Light as energy source -Organic compounds as C source - Chemicals as energy source - Organic compounds as C source Prokaryotes

37 Eu: True Karyon: Nucleus B- Eukaryotic Cell Animal Cell Plant Cell Page Compare between Animal and Plant cell? What are the functions of cell organelles ?

38 Fig. 7.7, Page 114 ميتوكوندريا غشاء بلازمى حهاز جولـﭽـى ريبوسوم الهيكل الخلوى جسم مُحلل جسم مركزى سوط حركى الشبكة الإندوبلازمية النواة المادة الوراثية نوية الجدار النووى حلمات دقيقة

39 Fig. 7.8, Page 115 فجوة مركزية بلاستيدة خضراء ثقوب بينية الجدار الخلوى

All cells are surrounded by a plasma membrane غشاء بلازمى. All cells are surrounded by a plasma membrane غشاء بلازمى. The semi-fluid substance المادة النصف سائلة within the cell is called “cytosol”, السيتوبلازم containing the cell organelles عِضيات الخلية. The semi-fluid substance المادة النصف سائلة within the cell is called “cytosol”, السيتوبلازم containing the cell organelles عِضيات الخلية. 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 عضيات صغيرة called “Ribosomes” that make proteins. All cells have tiny organelles عضيات صغيرة called “Ribosomes” that make proteins. 1). Prokaryotic and eukaryotic cells differ in size and complexity Similarities Similarities أوجه التشابه Page 112

A major difference الفرق الأساسى between prokaryotic and eukaryotic cells is the location of chromosomes موضع الصبغيات. A major difference الفرق الأساسى between prokaryotic and eukaryotic cells is the location of chromosomes موضع الصبغيات. – In an eukaryotic cell, chromosomes are contained in a true nucleus ( النواة ). – In a prokaryotic cell, the DNA is concentrated in the nucleoid ( شـبه نواة ) without a membrane ( بدون غـشاء ) separating it from the rest of the cell. – In prokaryotic cell, DNA is a single strand ( أحادى الشريط ) or double strand ( ثنائى الشريط ) DNA. But in eukaryotic cell, DNA is double strand. 1). Prokaryotic and eukaryotic cells differ in size and complexity Differences Differences أوجه الاختلاف 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. © 2013 John Wiley & Sons, Inc. All rights reserved.

Bacterium The structure of cells (96) © 2013 John Wiley & Sons, Inc. All rights reserved.

The structure of cells Plant cell © 2013 John Wiley & Sons, Inc. All rights reserved.

Animal cell The structure of cells (97) © 2013 John Wiley & Sons, Inc. All rights reserved.

Cellular reproduction: Eukaryotes and prokaryotes ( ) Cell division in eukaryotes DNA (blue) and microtubules (green) of two daughter cells. Bacterial conjugation Sharing of DNA through the F pilus © 2013 John Wiley & Sons, Inc. All rights reserved.

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

Classifications of Tissues 1. 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