TOPIC:Science: "Introduction to Cell Biology

SCIENCE

1. CELL BIOLOGY Prepared by: Ms. Salemah P. Salim, LPT

2. WHY STUDY BIOLOGY? Helps understand the functions and reactions of your body It explains similarities and differences with other organisms It helps to understand how animals survive, respond, and interact with their environment – biology involves in studying and examining other animals (specimens are used to further understand the body system) other life forms have vital role to keep the balance in their environment- food chain Causative agents of diseases such as bacteria Helps to respond to the demands of an increasing human population C onsumption are improved to answer the need for increased food population Plants are important in providing oxygen, food, medicines, and clothing It is a science that helps you think critically, make informed choices, and solve problems

3. Intro to Cell Biology Biology is the science that deals with structures, functions, and relationships of living things and their environment. –molecular, cellular, organismal, population, community or ecosystem The biosphere is the zone of life on Earth which comprise the sum total of all the ecosystems. The Marine census been identified 8.7 million species that have been identified but millions more have yet to be discovered. These abundance and diverse count, microscopic or not, simple or independent, or complex or multi-colonial, are all made of cells.

4. Cell prokaryotic eukaryotic Cell wall Plasma membrane Animal cell Plant cell Plasma membrane Plasma membrane Cell wall Energy processing Energy processing mitochondria mitochondria chloroplast Genetic control Breakdown and storage Manufacture and distribution Structural support and communication nucleus lysosome peroxisome vesicle peroxisome ribosome Endoplasmic reticulum Golgi apparatus cytoskeleton Extracellular matrix Cell junction

5. Cell Theory King Charles II commissioned a microscopic examination of the natural world, insect anatomy. Robert Hooke Glass, crystal, point of a pin Earliest microscopic Thin slice of cork from a bark of an oak tree Described it like honeycomb that has perforation and has porous surface, cellulae , Latin word for small room Drawings were collected in Micrographia and become best seller 1 st person credited in publishing of seeing a cell in 1666 the hollow chambers were walls left behind by the plant cell that is dead

6. Cell Theory Anton Van Leeuwenhoek He got copy of Hooke’s Micrographia 1 st to study magnified cell He devised his simple microscope blood, semen, feces, pepper, tartar, pond animalcules – little animals His detailed sketches aroused the curiosity to investigate the invisible world 1 st person to observe living cells in 1676

7. Cell Theory Robert Brown (1831) Able to compare kinds of plant specimens All composed of cells and each has dark dense spot Matthias Jakob Schleiden ( 1838) German botanist focused on plant cells He concluded all plant parts are made of cells Theodore Schwann (1839 ) German physiologist examined animal cells He stated that all animal tissues are composed of cell too

8. Cell Theory Rudolf Carl Virchow (1858) German physician He concluded that all cells come from previously existing cells through the process of process of cell division

9. Cell Theory Along with the finding of other scientists, they all confirmed that cells are fundamental units of life and that the bodies of living organisms are made up cells. The cell theory is universal for all living things, no matter how simple or complex, or tiny or huge it is. Cell theory can be summed up into three basics components. All living organisms are composed of one or more cells . An organism can be unicellular, one-celled or multicellular. A single-celled organism can perform all the essential functions that enable it to grow, survive and reproduce. Multicellular organisms are more complex in structure and function, but the mechanism on how they are able to live is still the same as with simple life forms.

10. Cell Theory 2. The cell is the basic unit of life in all living things . Cell operates similarly to a complete machine that has many compartments that perform different but interrelated and interconnected functions. 3. All cells come from pre-existing cells . Cell cannot be spontaneously created but always be a product of reproduction from pre-existing cell.

11. Basic Cell Type Biologist recognize two main types of cells; prokaryotes and eukaryotes Simple prokaryotes, pro “before” and karyon “nut”, before the nut Complex eukaryotes, eu “true” and karyon “nut”, true nut All living things have cells that share fundamental structural parts. Fundamental Structural Parts Cell membrane/plasma membrane – outer boundary, regulates the passage of materials into and out of the cell Cytoplasm – a gel-like substance, making up the cells internal environment Nucleus – a central genetic region, containing the genetic material in the form of DNA that provides instructions to make proteins, regulates activities, and enables cells to reproduce

12. Prokaryotes Smaller in size cell with simple internal structure that allow organism to reproduce very fast, can exist in great numbers in air, bodies of water, soil and even inside the bodies of living hosts Bacteria, blue green algae, archeans (bacteria living in extreme environment) Semipermeable membrane allows waste product to pass through while preventing the diffusion of essential products to the external environment Rigid cell wall is responsible for maintain its shape Some have capsule that acts as protective layer made of polysaccharides

13. Prokaryotes Nucleoid region stores its genetic material in the form of DNA Cytoplasm is not organized into distinct interior compartments Ribosomes are scattered all over cytoplasm\ Some possess a plasmid , an independent circular DNA structure apart from its chromosomal DNA Some possess appendages to enable cell to cell communication Flagellum/flagella, a tail like structure that can be seen at the end part or scattered randomly over the surface for locomotion Fimbriae, smaller and brittle-like fibre allows to attach themselves to surface such as doorknob or nostril Conjugation pili, tubular structures in cell surface for cell to cell communication to pass DNA from one bacterium to the next

14. Eukaryotes Fungi, plants, animals, protists Have genetic material (DNA) encased within a distinct nucleus Have many membrane-bound interior compartments and their organelles are neatly arranged Hooke’s analogy of the cell as a small room is useful, like a room, a cell is surrounded by walls that separates it from the rest of the outside environment while at the same time provides stable structure and support.

15. Cell structures for Protection Plasma membrane/cell membrane A thin barrier that forms a boundary Separate individual cell from the external environment -structural support It acts as gatekeeper to regulate the passage of important molecules, ions, and gases between outside and inside of a cell - maintains and limits the materials for the cell not to loose its identity and will not undergo cell abnormality Aka phospholipid bilayer Consists of a double layer of phospholipid in both prokaryotic and eukaryotic cells embedded with variety of molecules- provides protection Each phospholipid molecules composed of three basic parts, a. charged phosphate, b. glycerol , ( a and b are joined together to form the ‘head’ that bears charge considered as polar molecules), c. t wo fatty acids (make up the tail, nonpolar molecule) Semipermeable or selectively permeable-Separates the internal contents Passageway of ions, H2O, O2, CO2

16. Plasma membrane/cell membrane Nonpolar (hydrophobic) tails are attracted to each other while being repelled by water – thus face inward where there is no water Polar (hydrophilic) heads of the phospholipid layer are oriented in two different directions – in the exterior of the cell membrane, the phospholipid heads face toward the outside environment, while the other heads of the phospholipid molecules face the interior cytoplasm Membrane structures: 1.Cholesterol, 2. Carbohydrates, 3. Membrane Proteins (transport, channel, cell recognition, enzymatic, cytoskeleton, junction, receptor)

17. 1. Plasma membrane/cell membrane Cholesterol molecules helps strengthen the cell membrane, making it more flexible but less fluid which makes the membrane less permeable to water-soluble substances such as ions or simples sugars Carbohydrates attached to membrane proteins serve as identification tags, enabling cells to distinguish one type of cell from another Membrane Proteins ; a. transport – extend from the phospholipid layer to help materials across the membrane, b. channel – form tunnels that help cell to import or export needed materials and wastes, c. cell recognition – enable cells to distinguish own cells from that of other organisms, such as pathogens that may invade the body, d. enzymatic – participate in metabolic reactions such as degradative and synthetic reaction, e. cytoskeleton – act as muscle and skeleton to maintain cell shape and motility, f. junction – assist cell-to-cell adhesion and communication between cells, g. receptor – facilitate exchange of signals with other cells by changing shape to allow specific molecule, the ligand, to bind to it.

18. Cell structures for Protection 2 . Cell wall Plants, algae, fungi, bacteria’s cell membrane is surrounded by an additional boundary - Outermost covering of the cell Composed of multiple cellulose layer which is rigid that gives protection, provides strength and defines the shape of the cell Cell wall’s composition varies and is related to the different needs of each type of organism – in plants and algae (polysaccharide cellulose) since the molecules cannot easily pas across the cellulose, their cell walls have openings or channels to let water and other molecules to diffuse, in fungi (chitin), and bacteria (peptidoglycan)

19. Cell structures for Protection 3 . Cytoplasm Jelly-like structure that fills the space between the nucleus and cell membrane Cytosol is the fluid portion consisting mainly of water and excluding the organelles in it – it is necessary for maintaining cell structure. Many chemical reactions occur in the cytoplasm wherein water acts as natural solvent The cytoplasm provides shape to the cell It fills up the cells thus enabling the organelles to remain in their position

20. Genetic Control Organelles 4. Nucleus It is found in the middle of the cell and is the storehouse of genetic information in the form of DNA Control center of the cell compared to the chief operating officer of a company because it directs all activities of the cell following strictly the instructions n the operations manual (DNA) It performs crucial tasks such as protecting the DNA at all times from damage and its instructions must be made available for use at proper times – it must be kept safe inside the nucleus since there are molecules that may damage the DNA

21. Genetic Control Organelles DNA is a long chain of molecule which can be segmented into portions called genes that contain instructions for making proteins. It is packed by special group of proteins (histones – forming a complex structure called chromatin then further condenses to form tightly coiled structures - chromosomes) Many proteins are involved in turning the genes on and off, they need access to the DNA at certain times . The nucleus facilitates this demand by enclosing the DNA thru nuclear envelope (that is filled with holes nuclear pores that allow large molecules to pass between the nucleus and cytoplasm). It also possesses the nucleolus which is a dense region where small organelles essential for making proteins. ( ribosomes ) After ribosomes are formed in nucleolus, they are pass through the nuclear pores into the cytoplasm, where protein synthesis occurs.

22. Manufacturing, Storage, Distribution, and Breakdown Organelles 5. Endoplasmic Reticulum An interconnected network of thin and folded membranes fills much of the large portion of the cytoplasm It is arranged like a maze (interior of this maze-lumen) of enclosed spaces with many creases and folds The lumen and its surface are the sites for many processes such as the production of proteins and lipids. Some regions of the ER is dotted with ribosomes that join amino acids together to form proteins.

23. Manufacturing, Storage, Distribution, and Breakdown Organelles The surface of the ER covered by ribosome is called Rough Endoplasmic Reticulum – bumpy look under microscope As proteins are being made in the ribosomes, they enter the lumen where proteins are modified further with the addition of sugar chains adding to stability Proteins made on the ER are either incorporated into the cell membrane or secreted to areas where the body needs them Some ribosome not bound in the ER are suspended in the cytoplasm and used in chemical reactions within the cytoplasm Surfaces of the ER that are not studded with ribosomes are called Smooth Endoplasmic Reticulum that is responsible for the production of lipids and performance of other specialized functions, such as breaking down drugs and alcohol.

24. Manufacturing, Storage, Distribution, and Breakdown Organelles 6. Golgi Apparatus From the ER, proteins are transported into layered stacks of membrane-enclosed spaces called Golgi complex where proteins are processed, sorted, and delivered The membranes of the Golgi have enzymes that further modify the proteins. Finally, finished products are packed in this organelle. Some of the packed proteins are stored temporarily within the Golgi apparatus for later use. Some are transported to other organelles within the cell or carried to the membrane where they will be secreted out of the cell.

25. Manufacturing, Storage, Distribution, and Breakdown Organelles 7. Vesicles There are organelles that are physically interconnected with each other by means of membranes or by the transfer of materials through vesicles After a protein has been manufactured, part of the ER pinches off to form small, membrane-bound sacs called vesicles enclosing the protein. A protein protected by vesicle can be transported to the Golgi apparatus, where further modifications can be made. A new vesicle will again be formed at the end of the Golgi for storage , transport or secretion ( secretory ). They are generally short lived and are formed and recycled as needed by the cell. The synthesis, storage and export of the molecules is made possible because these organelles are functionally connected with each other. Instructions fro the nucleus pass out the thru nuclear pore to ER. Transport vesicles travel from ER to the Golgi then to other destinations Some vesicles may develop into lysosomes and vacuoles.

26. Manufacturing, Storage, Distribution, and Breakdown Organelles 8. Vacuoles It is a fluid-filled sac for the storage of materials need by the cell that includes water, food molecules, inorganic ions, and enzymes. Most animal cells contain many small vacuoles while plants have a central vacuole that is unique only to them A central Vacuole is a single large vacuole that takes up most of the space inside a plant cell – nucleus placed the side of the cell. It is filled with a watery fluid that strengthens the cell and helps supports the entire plant (erect). Plant wilts when not watered, its leaves shriveled because there is not enough water in each cell’s central vacuole to support the leaf’s normal structure. It also contains other substances such as toxins that can harm predators and protect the plant waste products that may harm the cell itself, and pigments that give colors to the petals