mbbs ims msu

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physiology

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  • 1. Cell Structure& Function

2. 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.

3. Definition of Cell A cell is the smallest unit that is capable of performing life functions. 4. Cell Classified to function

  • Muscle cell
  • Nerve cell
  • Epithelial cell
  • Connective tissue cell

5. Examples of Cells Amoeba Proteus Plant Stem Red Blood Cell Nerve Cell Bacteria 6. Two Types of Cells

  • Prokaryotic
  • Eukaryotic

7. Prokaryotic

  • Do not have structures surrounded by membranes
  • Few internal structures
  • One-celled organisms, Bacteria

8. Eukaryotic

  • Containorganelles(little organs) surrounded by membranes
  • Most living organisms

Plant Animal 9. Typical Animal Cell 10.

  • Cells are surrounded by cell membrane
  • The interior of the cell is divided:
    • Nucleus
    • Cytoplasm
    • The Cytoplasm contains two components
    • Cell organelles
    • Cytosol

11. Cell Parts Surrounding the Cell 12. Cell Membrane

  • Function of cell membrane
  • Regulate the passage of substance into and out of cell and between cell organelles and cytosol.
  • Link adjacent cells together
  • Detect chemical messengers arriving at the cell surface

13. The Cell Membrane Structure 14. Overview

  • Cell membraneseparatesliving cell from nonliving surroundings
    • thin barrier = 8nm thick
  • Made ofphospholipids ,proteins& other macromolecules

15. Phospholipids

  • Fatty acidtails
    • hydrophobic
  • Phosphategroup head
    • hydrophilic
  • Arranged as abilayer

Fatty acid Phosphate 16. Phospholipid bilayer polar hydrophilic heads nonpolar hydrophobic tails polar hydrophilic heads 17. More than lipids

  • In 1972, S.J. Singer & G. Nicolson proposed that membrane proteins are inserted into the phospholipid bilayer
  • Two types of membrane protein
  • Integral membrane
  • Peripheral membrane

18. Membrane is a collage of proteins & other molecules embedded in the fluid matrix of the lipid bilayer Extracellular fluid Cholesterol Cytoplasm Phospholipids Glycolipid Transmembrane proteins Filaments of cytoskeleton Peripheral protein Glycoprotein 19. Membrane Proteins

  • Proteins determine membranes specific functions
    • cell membrane & organelle membranes each have unique collections of proteins
  • Membrane proteins:
    • peripheral proteins
      • loosely bound to surface of membrane
    • integral proteins
      • penetrate lipid bilayer, usually across whole membrane
      • transmembraneprotein

20. Proteins domains anchor molecule

  • Within membrane
    • nonpolaramino acids
      • hydrophobic
      • anchors proteininto membrane
  • On outer surfaces of membrane
    • polaramino acids
      • hydrophilic
      • extend into extracellular fluid & into cytosol

Polar areas of protein Nonpolar areas of protein 21. Many Functions of Membrane Proteins Outside Plasma membrane Inside Transporter Cell surface receptor Enzyme activity Cell surfaceidentity marker Attachment to the cytoskeleton Cell adhesion 22. Membrane carbohydrates

  • Play a key role incell-cell recognition
    • ability of a cell to distinguish one cell from another
    • important in organ &tissue development

23. Membrane Junctions

  • Some cell not anchored to other cells but suspend in the fluid.
  • Most cells are packaged into tissues and are not free to move.
  • Many cells physically joined by specialized types:
  • Desmosomes
  • Tight junctions
  • Gap junctions

24. Inside the Cell 25. Nucleus

  • Almost all cells contain a single nucleus.
  • Directs cell activities
  • Separated from cytoplasm by nuclear membrane
  • Function-Stores and transmits genetic information in the form of DNA. Genetic information passes from the nucleus to the cytoplasm

26. Nuclear Membrane

  • Surrounds nucleus
  • Made of two layers
  • Nuclear envelope
  • Nuclear pores
  • Openings allow material to enter and leave nucleus

http://library.thinkquest.org/12413/structures.html 27. Chromosomes

  • In nucleus
  • Made of DNA
  • Contain instructions for traits & characteristics

http://library.thinkquest.org/12413/structures.html 28. Nucleolus

  • Inside nucleus
  • Contains RNA to build proteins

http://library.thinkquest.org/12413/structures.html 29. Endoplasmic Reticulum

  • Moves materials around in cell
  • Smooth type (Agranular): lacks ribosomes. Site of lipid molecule synthesized
  • Rough type (Granular): ribosomes embedded in surface. Packaging of proteins to be secreted or distributed.

http://library.thinkquest.org/12413/structures.html 30. Ribosomes

  • Composed of proteins and several RNA molecules
  • Proteins factories of the cell
  • Either bound to the organelle or found free in the cytoplasm

http://library.thinkquest.org/12413/structures.html 31. Golgi Apparatus

  • Most cells have single Golgi apparatus.
  • Protein 'packaging plant'
  • Move materials within the cell
  • Move materials out of the cell

http://library.thinkquest.org/12413/structures.html 32. Lysosome

  • Spherical or oval
  • Typical cell may contain several hundreds
  • Digestive enzyme for proteins, fats, and carbohydrates
  • Transports undigested material to cell membrane for removal
  • Cell breaks down if lysosome explodes

http://library.thinkquest.org/12413/structures.html 33. Mitochondria

  • Spherical rode like structure
  • 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

http://library.thinkquest.org/12413/structures.html