1. An Introductory Overview of Cells Lecture no.3 28/02/20161

2. What We Will Be Covering-I? What is a Cell? The Two Types of Cells ? The Exception? The Organelles and Their Functions. 28/02/20162 Lecture no.3

3. Life begins with cells Cell came from Latin word mean small room. A cell is the functional and structural unit of all living organism. The Cell Theory --1839 by the German botanist Matthias Jakob Schleiden and German physiologist Theodore Schwann. 28/02/20163 Lecture no.3

4. Cell Theory All living things are made up of cells. Cells are the smallest working units of all living things. All cells come from preexisting cells through cell division. 28/02/20164 Lecture no.3

5. Examples of Cells Bacteria Plant Stem Red Blood Cell Nerve Cell Amoeba Proteus 28/02/20165 Lecture no.3

6. Types of Cells 1.Prokaryotic Bacteria Archaea 2. Eukaryotic Unicellular Protists Multi-cellular Fungi Plants Animals 28/02/20166 Lecture no.3

7. Prokaryotic Cells Characteristics Unicellular (some multi-cellular). Lacks a membrane bound nucleus. Lacks membrane bound organelles. Has a cell membrane and cell wall. Has ribosomes (protein production). Circular DNA. 28/02/20167 Lecture no.3

8. Eukaryotes Characteristics Unicellular (Protists). Multicellular (fungi, plants, animals). Membrane bound Nucleus. Contains Organelles. Linear DNA. Typical plant cell Typical animal cell 28/02/20168 Lecture no.3

9. Types of Eukaryotic Cells 1. Somatic Greek for “body’’ All cells in the body except the sex cells. Found in the bones, skin, organs, tissues, blood. Reproduce by Mitosis. All somatic cells in a human body have the same genetic information (except RBC) 2. Germ The Sex Cells. Sperm and Ova. Reproduce by Meiosis. Are haploid e.g. in humans: 23 chromosomes 28/02/20169 Lecture no.3

10. Is there any exception ? 28/02/201610 Lecture no.3

11. The Exception: Viruses Characteristics Latin for “poison”. Does not meet all the criteria of “Life” Viruses are not cells; they are supra- macromolecules made of two types of macromolecules i.e. proteins and nucleic acids Outer coat is made of proteins and inner core is nucleic acid, which may be either DNA or RNA, but not usually both. Require a host to replicate. 28/02/201611 Lecture no.3

12. Cell Parts Organelles 28/02/201612 Lecture no.3

13. I- Surrounding the Cell 28/02/201613 Outer membrane of cell that controls movement in and out of the cell. Made of phospholipid bilayer with embedded proteins (enzymes, receptors, channels etc). Place of communication with the environment and other cells. “Gate of the Cell”. Outer membrane of cell that controls movement in and out of the cell. Made of phospholipid bilayer with embedded proteins (enzymes, receptors, channels etc). Place of communication with the environment and other cells. “Gate of the Cell”. - Cell Membrane - Cell wall Most commonly found in plant cells & bacteria. Made of mucopolysaccharides (yeast, procaryotes) or cellulose (plants) “Supports & protects cells”. “Supports & protects cells”. Most commonly found in plant cells & bacteria. Made of mucopolysaccharides (yeast, procaryotes) or cellulose (plants) “Supports & protects cells”. “Supports & protects cells”. Lecture no.3

14. II- Inside the Cell 28/02/201614 First described by Robert Brown in 1831. Largest organelle. Separated from cytoplasm by nuclear membrane in eucaryotes. Contains genetic material – DNA. “Control Center” - Nucleus Double membrane envelop that surrounds nucleus. Contains nuclear pores which is place of selective transport between cytoplasm and inside of nucleus (proteins, mRNA) “Gate of the Nucleus” - Nuclear membrane Lecture no.3

15. Continue… 28/02/201615 In nucleus. Present in the form of strings of DNA and histones. Contain instructions for traits & characteristics. “Director of the Cell” - Chromosomes Inside nucleus. The nucleolus plays an indirect role in protein synthesis by producing ribosomes. Nucleolus is not a structure!!! Just a visible region. - Nucleolus Lecture no.3

16. Chromosomes in eukaryotes & prokaryotes are different PROKARYOTESEUKARYOTES single chromosome plus plasmidsmany chromosomes circular chromosomelinear chromosomes made only of DNAmade of chromatin, a nucleoprotein (DNA coiled around histone proteins) found in cytoplasmfound in a nucleus copies its chromosome and divides immediately afterwards copies chromosomes, then the cell grows, then goes through mitosis to organise chromosomes in two equal groups © 2007 Paul Billiet ODWSODWS Lecture no.3

17. Constant for each cell in the body (except sex cells which only have half sets). Constant throughout the life of an individual. Chrosomes are of two types: autosomes (same in males and females) and sex (X and Y) chromosomes Constant for all members of a species. Numbers of chromosomes Lecture no.3

18. Human Genome Basics Most human somatic cells are diploid, having 2 copies of each chromosome, one from each parent. The gametes, sperm & egg, are haploid, with 1 copy of each chromosome. Humans have a haploid number n of 23, meaning that there are 23 chromosomes in a complete haploid set. Thus, gametes have 23 chromosomes and diploid cells have 46. The pairs of chromosome in a diploid cell are called homologues. The X and Y chromosomes are sex chromosomes, and the other 22 chromosomes are called autosomes. Normal males are XY and normal females are XX. Thus, sperm cells either contain an X or a Y. Eggs always contain an X chromosome. Lecture no.3

19. Conti… In somatic cells: diploid (2n) cell: 23 x2= 46 chromosomes : 22 pair of autosomes + XY chromosomes : 22 pairs of autosomes + XX chromosomes In germ cells: Sperms are of two types: 22 autosomes + Y chromosome 22 autosomes + X chromosome Ova has: 22 autosomes + X chromosome 28/02/201619

20. 28/02/201620 Chromosomes and reproduction Lecture no.3

21. 28/02/201621 Gel-like material. The portion of the cell enclosed by the cell membrane but not part of any organelle It stores the organelles, water, and the chemicals in it. “Area of Movement”. “Area of Movement”. - Cytoplasm The transportation center for the cell. Smooth and rough types. SER Site of fatty acid and phospholipid synthesis, While RER place of extracellular proteins synthesis -Endoplasmic Reticulum Continue… Lecture no.3

22. 28/02/201622 Found in the cytoplasm and on the ER. Their job is to make proteins. The nucleus makes the ribosomes. - Ribosomes Place of oxidative metabolism and ATP production. Contains its own DNA and ribosomes. “Powerhouse of the Cell” - Mitochondria Continue… Lecture no.3

23. 28/02/201623 Package and to move protein to the out side of the cell. They also process proteins from ribosomes that are located on the ER. - Golgi Bodies Digest the wastes and unwanted organelles. Acidic organelles - low pH due to proton pump (pH=5) in the membrane. Contain many degradative enzymes such as acid hydrolases. - Lysosome Continue… Lecture no.3

24. 28/02/201624 Tay-Sachs disease : is a genetic defect in one of specific lysosomal hydrolases

25. 28/02/201625 The vacuole in the plant cell is larger than the vacuole in the animal cell. Membrane-bound sacs for storage, digestion, and waste removal. “Storage Tanks”. “Storage Tanks”. - Vacuoles Contains green chlorophyll. Where photosynthesis takes place. “Food Producers”. - Chloroplast Continue… Lecture no.3

26. Summary 28/02/201626 Lecture no.3

27. See you later to continue with the The structure and properties of Nucleotides 28/02/201627 Lecture no.3