BIO1-PRELIM-W1-2-L1-CELL THEORY, STRUCTURES AND FUNCTIONS.pptx

Lecture presentation

1. General Biology 1 11 th Grade - STEM

2. Thi s sub j ect i s des i gned t o enhance the understanding of the pri n cipl e s a n d c on c e p ts i n the s tudy of biolo g y , particularly life processes at the cellular and molecular levels. It also covers the transformation of energy in organisms. COURSE DESCRIPTION

3. LESSON 1: THE CELL (Theory, Structure and Functions)

4. At the end of the lesson, you should be able to: Recite the postulates of cell theory and explain the roles of a cell in an organism, particularly in the levels of organization of an organism; Descr i b e the s t r uctu r e a n d fu n ct io n s of major a n d sub c e l l u lar organelles; Determine the role of each cellular organelle and explain how it relates to the functions of other organelles. Learning Outcomes:

5. History of cell In 1665, British scientist Robert Hooke examined a piece of cork and found little structures in it which he compared to cellulae . He named these structures “cells”. Later it was discovered that the cell he had found in the cork w e r e actually outer walls of former pla n t cell.

6. HISTORY OF CELL In the late 1600’s, Dutch scientist Anton van Leeuwenhoek examined different subjects , using a refined microscope than that of Hooke. protist Leu w enhoek and sperm, f o u n d m o ving which he collectively termed “animalcules”

7. Cell Theory: Definition The Cell Theory, developed in the mid-1800’s as a result of various discoveries about cells, it is one of the basic principles of biology. The cell is the basic unit of life; All living organisms are composed of cell; and New cells are created from pre-existing cell

8. First Postulate: Cell is the basic unit of life I n o r de r th a t a n o r g a nis m m a y be considered living, it must have a cell. On e p r oo f th a t an o r g an i s m i s ali v e ju s t b y look i n g a t it s cell i s the movement of the organelles inside it.

9. First Postulate: Cell is the basic unit of life In the cork that Hooke examined, the protoplasm of the cell had already dissipated, indicating the cell’s death. When Leeuwenhooek observed his teeth scrapings, he found animalcules shooting and spinning inside the cell.

10. Second Postulate: ALL LIVING ORGANISMS ARE COMPOSED OF CELL In 1838, German botanist Mattthias Jacob Schleiden established that the small compartments in his plant specimens are cells. In 1839, a German zoologist named Theodore Schwann after doing microscopic studies of animal cells, instituted that all animals are also composed of cells.

11. Third Postulate: new cells are created from pre-existing cells German scientist Rudolf Virchow introduced the third tenet of the cell theory: Omnis cellula e cellula which means “Cells come from pre-existing cell”.

12. Development of Cell Theory 1590 – Zacharias Janssen invented a primitive microscope with the help of his father Hans. 166 3 -1665 – R obert H o o k e viewed a thin slice of cork

13. Development of Cell Theory 1665-1676 Marcello Malpighi and Nehemiah Grew conducted separated investigations on plant cell. They determined the presence of organelles within its cells .

14. Development of Cell Theory 1670-1683 Anton van Leeuwenhoek upgraded Janssen’s microscope and produced his lens. With this invention, he discovered mobile organelles in many subjects, which he called animalcules .

15. Development of Cell Theory 1831- Robert Brown made a series of discoveries about cell organelles and ultimately discovered the nucleus . This became a major breakthrough in the history of biology.

16. Development of Cell Theory 1838 Matthias Schleiden microscopically examine plants and recognized that plant parts come from cells. In his writings in Contribution in Phytogenesis , he proposed that the different structures of a plant are all composed of cells.

17. Development of Cell Theory 1839 Theodore Schwann declared that animals are likewise composed of cells. This put an end to the debates – whether or not plants and animals are different in structural origin and composition.

18. Development of Cell Theory 1840 Albrecht von Roelliker stated that sperm and egg are composed of cells and that all humans are configured from cells. 1849 Louis Pasteur was developing fermentation, a process to kill bacteria, he proved that bacteria are able to multiply and that bacterial cells come from other bacterial cells.

19. Development of Cell Theory 1858 Rudolf Virchow declared, “Omnis cellula e cellula” which he meant that cells come from pre- existing cells. With this conclusion, the cell theory was completed.

20. Question! If life were to be found in other planets, would you expect it to form cells? Why or why not?

21. ASTROBIOLOGY Our space exploration has been continually searching for life in outer space. On the space probes sent to other planets (especially Mars), these are equipped to look after life. However, very high resolution are still not possible on-site.

22. Cell Structure and Functions

23. MAJOR PARTS OF THE CELL Cytoplasm Consisting of a jelly-like cytosol within the cell in which other cellular components are found. Nucleus S e r v es as the b r ain of the cell and d i r ects all of the cell ’ s activity. Plasma Membrane A phospholipid bilayer with embedded proteins that separates the internal contents of the cell from its surrounding environment.

24. Plasma Membrane It encloses and safeguards its organelles from possible harm that foreign materials can inflict on them.

25. Plasma Membrane I t a l s o c o n t r ol s the exchange of essential components and obtains chemical messages from other cells. Wastes such as CO 2 and NH 3 also leave the cell through it.

26. Plasma Membrane: FLUID MOSAIC MODEL Th e plasma mem b r ane i s a mosaic primarily, phospholipids , cholesterol , of c ompone n t s — and p r o t eins —th a t move freely and fluidly in the plane of the membrane.

27. Components of Plasma Membrane 1. Phospholipids It is a lipid made of glycerol, two fatty acid tails, and a phosphate-linked head group. Biological membranes usually involve two layers of phospholipids with their tails pointing inward, an arrangement called a phospholipid bilayer .

28. Components of Plasma Membrane 2. Cholesterol It is another lipid composed of four fused carbon rings, is found alongside phospholipids in the core of the membrane.

29. Components of Plasma Membrane 3. Proteins Proteins help move large molecules or aid in cell recognition Peripheral proteins are attached on the surface (inner or outer) I n t eg r al p r o t eins a r e em b edded c o m pl e t ely th r ou g h the membrane

30. CYTOPLASM I t i s the e n t i r e r egion of a cell b e t w een plasma membrane and nuclear envelope. It is composed primarily of water, proteins and salts.

31. CYTOPLASM In the c y t o p lasm, the o r g anel l es a r e suspended in a gel-like solution called cytosol , which i s c ompose d of bot h o r g anic a nd inorganic compounds. C y t oso l ac c ou n ts f o r about 70 % of cell u lar c o n t e n t . I t c o n t ains a rich s u p pl y of s m a ller o r g anic mac r omolec u les and molecules.

32. CYTOPLASM Th e C y t oplas m al s o c o n t ains en z ymes that break down waste and enable metabolic reactions. It allows for cellular expansion and growth. Together d e t er m ines with c y t os k el e t on , c y t opl a sm cell shap e a n d ac c o m m od a t es movement for some cell types.

33. Nucleus Discovered by Robert Brown in 1833. It is the most vital part of the cell and dubbed as the “control center” It directs all of the cell’s activities and determines how a cell should appear and function.

34. Nucleus A double layer of nuclear membrane encloses the nucleus to keep it distinct from other cellular components. Nucleolus serves as the site of ribosomes synthesis. Nucleus holds chromosomes which carry tightly wrapped and coined DNA .

35. The cell organelles: endomembrane system The endomembrane system is a group of membranes and organelles in eukaryotic cells that works together to modify , package , and transport lipids and proteins.

36. The cell organelles: endomembrane system This system is made up of organelles that are communally linked by structure specific to each of them. These organelles are: Lysosomes Peroxisomes Centrosomes Endoplasmic Reticulum Ribosomes Vacuoles Golgi Apparatus

37. Endoplasmic R eticulum

38. Endoplasmic R eticulum The En doplas m ic R e t i culum ( ER) interconnected membranous sacs i s a ser i es of a n d tub u les th a t collectively modifies proteins and synthesized lipids . These two functions are perform ed in separate areas of E R; the r oug h endopla s mic r e t i culum a n d smo o th endoplasmic reticulum .

39. Endoplasmic R eticulum The hollow portion of ER tubules is called lumen or cisternal space . The membrane of the ER, which is a phospholipid bilayer embedded with proteins , is continuous with nuclear envelope.

40. Rough E ndoplasmic R eticulum It has ribosomes on its surface. It makes membrane proteins and proteins for export out of cell. Proteins are made by ribosomes on ER surface They are then threaded into the interior of the Rough ER to be modified and transported

41. S mooth E ndoplasmic R eticulum It incorporates proteins into cisternae and transports synthesized proteins across the cytoplasm, thereby allowing the s y n the s is of f a t ty acids a n d phospholipids. It is abundant in liver cell, where it detoxifies hydrophobic chemicals. This makes them water-soluble for excretion.

42. RIBOSOMES

43. CELLULAR STRUCTURES

44. RIBOSOMES Ribosomes a r e i n v ol v ed i n p r ov i din g a f r ame f or proteins synthesis; hence they are site of protein production. Th e y a r e p r ese n t i n bot h pro k a r yot i c and eu k a r yotic cells . D e v elopi n g muscle cell s , s k in a n d h a ir cells c o n t a i n large numbers of free ribosomes.

45. Vacuoles

46. Vacuoles A vacuole is a fluid –filled vesicles enclosed by a membrane. It has a selectively membrane freely allowing water passage but retaining smaller molecules within it and stores chemicals within the cell. Vacuoles ability to break down large molecules makes it comparable with lysosomes in animal cells. Likewise, both organelles thrive in acidic environment.

47. L ysosomes

48. L ysosomes The lysosomes serve as digestion slots for cellular materials that are due for expiration or are no longer useful. It is the cell’s reprocessing area, where it hacks chemical bonds of any foreign substance it comes contact with, in order to recycle with the raw material

49. L ysosomes It is dubbed as the cell’s “suicide bags” These organelles are capable for self-destruction In order to save the rest of the other organelles from being poisoned. This happens through autophagy , or the natural process of organelle destruction.

50. LYSOSOMES Cells take in food by phagocytosis Lysosomes digest the food & get rid of wastes Example: macrophages

51. P eroxisome

52. P eroxisome s I t is a small , r oun d o r g anelles enc l o s ed b y single membrane, somehow resembles that of a lysosomes. I t i s r esponsible f o r sel f- d a ma g e a n d mo s tly disintegrate proteins , accommodate the breakdown of fatty acids and detoxify many poisons that enter the body. It also shields the cell from serious damage caused reactive oxygen species (ROS) molecules

53. Golgi APPARATUS

54. Golgi APPARATUS Stacks of flattened sacs H a v e a shipp i ng s i de ( ci s f a c e ) & a receiving side (trans face) Receive proteins made by ER T r ansport v esicl e s with modifi e d proteins pinch off the ends CIS TRANS Tr a nsport vesicle

55. Golgi APPARATUS a stack of pancakes Modify, sort, & package molecules from ER for storage OR transport out of cell

56. CENTROSOME

57. CENTROSOME It comprised of two centrioles or cylindrical structures with a central cavity surrounded by microtubules arranged side by side. These structure take part in the assembly of spindle fibers at cell division and contribute to the successful outcome of mitosis.

58. CENTROSOME It is found in all eukaryotic cells, assist in arranging microtubules (hollow tubes of proteins) to be utilized for cell division. They also enable the said microtubules to form part of the cell’s microtubules to form part of the cell’s cytoskeleton. In this way, cellular shape is maintain and the cell structure is stabilized.

59. M itochondri a

60. mitochondria Mitochondria are the sites of cellular respiration , the metabolic process that uses oxygen g e n e r a tion extracting ener g y t o dri v e the of A T P by from sugars, fats, and other fuels .

61. ADENOSINE TRIPHOSPHATE It is the major energy currency of the cell that provides the energy for most of the energy-consuming activities of the cell. Mechanism: When the third phosphate group of ATP is removed by hydrolysis, a substantial amount of free energy is released.

62. MITOCHONDRIA Th e mi t ocho n dri a a r e o v a l - shaped organelles found in most eukaryotic cells. Th e y a r e c o n s i de r ed t o b e the ‘powerhouses’ of the cell . Mi t ochondri a a r e mo s t ple n tiful i n cells th a t r e qui r e s i gnifi c a n t ene r gy t o funct i on , such amo u n ts of as l i v er and muscle cells.

63. MITOCHONDRIA The mitochondria has two membranes that are similar in composition to the cell membrane: Outer membrane —is a selectively permeable membrane that surrounds the mitochondria. It is the site of attachment for the respiratory assembly of the electron transport chain and ATP Synthase. It has integral proteins and pores for transporting molecules just like the cell membrane

64. MITOCHONDRIA Inner m e mb r an e — f old s i n w a r d ( c al l ed cri s t ae) t o i n c r ease s ur f a c es f or cellular metabolism. It c o n t ains rib o so m es a n d th e DN A of the m i t o ch o ndri a . Th e inner membrane creates two enclosed spaces within the mitochondria: I n t e r m emb r a n e sp a c e b e t w e en t h e o u t er me m b r a n e a n d t h e i n ner membrane; and matrix that is enclosed within the inner membrane.

65. CHLOROPLAST

66. CHLOROPLAST Chloroplasts, which are found in plants and algae, are the sites of photosynthesis . This process converts solar energy to chemical energy by absorbing sunlight and using it to drive the synthesis of organic compounds such as sugars from carbon dioxide and water.

67. CHLOROPLAST Chlo r opla s ts a r e doubl e m e mb r an e - bound organelles and are the sites of photosynthesis. The chloroplast has a system of three membranes: the outer membrane , the inner membrane , and the thylakoid system .

68. Structure of chloroplast Outer membrane —This is a semi-porous membrane and is permeable to small molecules and ions which diffuse easily. The outer membrane is not permeable to larger proteins.

69. Structure of chloroplast Intermembrane Space —This is usually a thin intermembrane space about 10-20 nanometers and is present between the outer and the inner membrane of the chloroplast.

70. Structure of chloroplast In n e r mem b r an e — Th e inner mem b r ane of the chlo r opla s t f orm s a bo r de r t o the stroma. It regulates passage of materials in and out of the chloroplast. I n addi t ion regulation activity, fatty acids, t o the and a r e s y n thesi z ed i n the inner chlo r opla s t membrane.

71. Structure of chloroplast Stroma —This is an alkaline, aqueous fluid that is protein-rich and is present within the inner membrane of the chloroplast. It is the space outside the thylakoid space. The chloroplast DNA, chloroplast ribosomes, thylakoid system, starch granules, and other proteins are found floating around the stroma.

72. Structure of chloroplast Thylakoid System The thylakoid system is suspended in the stroma. It is a collection of membranous sacks called thylakoids . Thylakoids are small sacks that are interconnected.

73. Structure of chloroplast The membranes of these thylakoids are the sites for the light reactions of the photosynthesis to take place. The chlorophyll is found in the thylakoids. The thylakoids are arranged in stacks known as grana. Each granum contains around 10- 20 thylakoids.

74. Practice: HOMEWORK Draw and label each part of plant and animal cell in a short bond paper.

75. EN R ICHME N T Why cells are generally small in size?