Cell_structure_function.ppt
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The document discusses the discovery of cells by Robert Hooke in 1665 and presents the cell theory, which states that all living organisms are made up of cells, the smallest working units. It differentiates between prokaryotic and eukaryotic cells, highlights the roles of various cell organelles such as the nucleus, mitochondria, and lysosomes, and explains their functions in cellular activities. Additionally, it describes parts of cells like the cell membrane and cytoplasm, emphasizing the importance of cells as the basic structural and functional units of life.
Cell_structure_function.ppt
- 1. Living Beings and their Structures
- 2. The Cell
- 3. Discovery of the cell: • Robert Hooke in 1665, observed thin slice of cork under self built microscope. • Partitioned boxes or compartments in the slice • Like a honeycomb • Hooked coined the term ‘cell’ for each box derived from Latin word ‘cella’ which means small room.
- 4. Cell Theory • Basic structural units; All living things are made up of cells. • Cells are the smallest working units of all living things. • All cells come from pre-existing cells through cell division. • Millions of living organisms of different shape and sizes.
- 5. Definition of Cell The basic structural and functional unit of life is known as cell. Why is cell known as basic structural and functional unit of life? • The function of an organism as a whole is the outcome of combined activities and interactions of the constituent cells.
- 6. Examples of Cells Amoeba proteus Plant Stem Red Blood Cell Nerve Cell Bacteria
- 7. Types of Cells •Prokaryotic cell (size 0.2-2.0 micrometer) •Eukaryotic cell (size 10-100 micrometer) On the basis of nuclear organization, are of two types:
- 8. Prokaryotic (pro = primitive and karyon = nucleus i.e. primitive nucleus) • Do not consists true nucleus • Do not have membrane bound organelles such as mitochondria, endoplasmic reticulum etc. • Few internal structures • One-celled organisms, Bacteria
- 9. Eukaryotic (eu = true and karyon = nucleus i.e. true nucleus) • Have true nucleus (DNA and RNA) • These cells have membrane bound organelles • Present in most living organisms Plant cell Animal cell
- 12. Different Parts of Cell Cell Organelles
- 13. Cell wall Cell membrane Cytoplasm Nucleus Mitochondria Golgi complex Endoplasmic Reticulum Ribosomes Lysosomes Vaculoe Plastid
- 14. Cell Wall • Most commonly found in plant cells (cellulose) & bacteria (chitin) • Supports & protects cells and maintains rigidity • Exhibits filtering mechanism
- 15. Cell Membrane (Plasma membrane) • Outer membrane of animal cell • Made up of lipid and protein molecules • Allows entry of useful materials and exit of unwanted materials • Provide shape to animal cell • Holds cytoplasm and organelles, and protects from external injury Why it is known as semi-permeable membrane?
- 16. Cytoplasm (Protoplasm) • Gel-like mixture (organic and inorganic materials like; water, minerals, salts, proteins etc.) • Helps in intracellular distribution of materials • Surrounded by cell membrane • Holds sub-cellular organelles • Contains hereditary material (prokaryotic cell)
- 17. Nucleus • Directs cell activities • Separated from cytoplasm by nuclear membrane • Contains genetic material – DNA • Helps in cell division and hence in reproduction Why nucleus is known as brain or director of the cell?
- 18. Nuclear Membrane • Surrounds nucleus • Made of two layers • Openings allow material to enter and leave nucleus
- 19. Nucleoplasm • Transparent semi-fluid substance • Contains nucleolus, chromatin network and various enzymes • maintain the shape and structure of the nucleus
- 20. Nucleolus • Inside nucleus, dense and round structure attached to chromatin fiber • Contains RNA to build proteins
- 21. Chromatin fiber (chromosome) • Contains hereditary information • Made of DNA • Contain instructions for traits & characteristics • 23 pairs of chromosomes are found in human being
- 22. Mitochondria • Produces energy through chemical reactions – breaking down fats & carbohydrates • Controls level of water and other materials in cell • Recycles and decomposes proteins, fats, and carbohydrates • Holds genetic material, DNA called mitochondrial DNAs • Stores energy in the form of ATP (adenosine triphosphate) Why mitochondraiis known as powerhouse of the cell?
- 23. Golgi Bodies • Golgi complex, Golgi apparatus or Golgi • Protein 'packaging plant‘ (process, package and store macromolecules synthesized by the cell) • Helps in the synthesis of hormones, glycoproteins etc. • Move materials out of the cell • Responsible for synthesis of cell wall, cell membrane and lysosomes
- 24. Endoplasmic Reticulum • Helps in the synthesis of proteins, fats and lipids • Moves materials around within a cell, acts as a pathway • Supports framework of the cell • Smooth type: lacks ribosomes • Rough type (pictured): ribosomes embedded in surface
- 25. Ribosomes • Each cell contains thousands • Found on endoplasmic reticulum or floating freely throughout the cell • Made up of complexes RNAs and proteins (ribonucleoprotein complex) • Responsible for synthesis of proteins
- 26. Lysosome • Hydrolytic enzymes (digestive enzymes), proteins, fats, and carbohydrates • More than 60 enzymes, (protein or food digestion) • Transports undigested material to cell membrane for removal • If lysosome explodes , digestive enzymes starts to digest own cell • Why it is called suicidal bag?
- 27. Vacuoles • Membrane-bound sacs for storage, digestion, and waste removal • Contains water solution • Help plants maintain shape
- 28. Plastids On the basis of pigments found on plastids, they are of three types: • Chloroplast (kithcen of the cell) • Chromoplast (Colourful) • Leucoplast (colourless)
- 29. Chloroplast • Usually found in plant cells • Contains green chlorophyll • Where photosynthesis takes place