CELLS- The basic unit of life


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Life science Grade 10

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CELLS- The basic unit of life

  1. 1. • Name: Gugu Msana • Student number: 201181428 • Module : Professional studies 3a • Course: B. Education • List of sources provided in the last slide
  3. 3. what is a cell ? Cell is the basic unit of life. All organisms are composed of cell Some organisms are unicellular .eg: bacteria And while some are multicellular . eg: human Cell is the fundamental structural and functional unit of all living organisms.
  4. 4. PLANT CELL
  6. 6. History of cell study Robert hooke-1665 Coined the word “cell”. Looked at cork cells. Robert brown-1831 Discovered the “nucleus”. Theodor Schwann- 1838 Cells are unit of biological structures. Mattias Schleiden-1850 Cell are the fundamental basis of life. Virchow-1858 All cells come from cells.
  7. 7. Theodor Schwann Mattias Schleiden Rudolf Virchow Robert Brown
  8. 8. 1. Every organisms is made up of at least one cell. 2. Cells are the basic structural and functional unit of multicellular organisms. 3. All cells arise from preexisting cells.
  9. 9. CELL WALL 1. a non living rigid structure . 2. Forms an outer covering for plasama membrane. function: 1) Determining Cell Shape. 2) Strength. 3) Controlling Turgor Pressure. 4) Passage of Substances. 5) Protection. Primary wall: • The wall which help to grow in youger plant • diminishes as cell get mature.
  10. 10. Endomembrane system contains only those organelles whose functions are coordinated. It consists of:  Endoplasmic reticulum(ER)  Golgi complex  lysosomes  Vacuoles
  11. 11. Discovered by porter and thompson.  ER are a network of tiny tubular structures scattered in the cytoplasm.  consists of 30-40% of endomembrane system  ER divides into 2 compartments. 1. luminal(inside ER) 2. extra luminal(cytoplasm) FUNCTIONS: 1. Mechanical support 2. Conduction of information 3. Intercellular transport 4. Localization of enzyme 5. Large surface area.
  12. 12. Endoplasmic reticulum cont…. • Dicovered by porter and thompson. • It is a complex membrane lined network of flattened sac, tubles etc.. • runs through out cytoplasm of eukaryotic cells. • Cosist of 30-40% of total endomembrane system. • Divides the intercellular space into components. Luminal and extraluminal
  13. 13. • Has two main types: Smooth endoplasmic reticulum and rough endoplasmic reticulum. Functions: 1. Mechanical support 2. Conduction of information 3. Intercellular transport 4. Localisation of enzymes. 5. Large surface area. Function of RER: 1. Protein for transport 2. Protein processing Function of SER: 1. Storage. 2. Glycogenolysis.
  14. 14. Golgi apparatus • Is a cytoplasmic organelle osf smooth membrane sac. • Dicovered by camillo golgi, • Found in eukaryotic cells (except mammalian erythrocytes) • Occur between nucleus and exposed cell surface. • Surrounded by zone of cytoplasm which is devioded of ribosomes, mitochondria, etc... Functions: Package materials. And important for formation of glycoprotein.
  15. 15. Lysosomes and vacuole lysosomes • Membrane bound vesicular structure • Formed by packaging of golgi appartus. • Very rich in hydrolytic enzymes. • Enzymes are capable for digesting carbohydrate, protein, lipid, mucleic acid. • Polpularly called as “suicide bags”, Vacuoles: • Membrane bound space found In cytoplasm. • Bounded by single membrane called tonoplast, • In amoeba, called contractile vacuole and in proista food vacuole
  16. 16. mitochondria• These are double –membrane bound, sausage – shaped semi-autonomous organelles. • The electron micrograph shows that the boundarymembranes are separated by a fluid filled spacecalled outer compartment. • The outer membrane is smooth but the inner smooth projects in the form of many folds calledcristae into the matrix. • The matrix is rich in enzymes, a circular DNA • molecule and many small ribosomes. • The inner membrane and the cristae bear a number of particles, which have a spherical head– piece (F1 subunit) and a stalk (F0 subunit) that is embedded in the lipid of the membrane. • The F0 – F1 combination functions as ATP synthetase. • The main function of mitochondria is aerobic respiration and ATP synthesis
  17. 17. …Plastids…Found in plants and euglenoids. They are large They contain pigments, imparting colors and storage products. Plastids can be classified into: *CHLOROPLAST *CHROMOPLAST *LEUCOPLAST •Contains chlorophyll and carotenoid pigments. •Found mainly in mesophyll of leaves . •These are lens shaped, oval shaped, spherical, discoid or even ribbon-like organelles. •Contains fat soluble carotenoid pigments like carotene, xanthrophylls and others are present. •Found in yellow, orange, red. •Colorless plastids •Various shapes and sizes with stored nutrients •LEUCOPLAST can be divided into 3:- 1.Amyloplasts – store carbohydrates 2.Elaioplasts – store oils and fats 3. Aleuroplasts – store proteins.
  18. 18. plastids• Plastids are double – membrane bound organelles of different shapes, that are found only • in plant cells and contain pigments and storage products. • These are three types of plastids, depending on their colour and functions. • Chromoplasts • These are the coloured plastids containing mainly the yellow, red and orange pigments (carotene and xanthophylls). • (iii) Chloroplasts • These are the green plastids containing mainly chlorophylls and very little of carotene and xanthophylls. • Chloroplasts may be lens – shaped, oval,spherical, discoid, ribbon-like or cup –shaped • Each chloroplast has a double membrane • covering, enclosing the colourless matrix • called stroma.
  19. 19. Reference list • Robayda, A. (2013). cell the unit of life. Available: http://www.slideshare.net/AishaRobayda/cell-the-unit-of-life-1?qid=12bc18e8-e13c- 4232-9b02-cf1652411b05&v=qf1&b=&from_search=3 (Accessed 07 march 2014) • ittah,E. (2013). Cell- The basic Structure of life. Available: http://www.slideshare.net/ericittah/eric-ittah-canada-eric- ittah?qid=12bc18e8-e13c-4232-9b02-cf1652411b05&v=qf1&b=&from_search=5 (accessed 07 march 2014) • Baiju, V. (2011). Cell The unit of life. Available: http://www.slideshare.net/VigneshBaiju/cell-the-unit-of-life- 10230437?qid=12bc18e8-e13c-4232-9b02- cf1652411b05&v=qf1&b=&from_search=8 (accessed 07 march 2014)