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1.1 cell structure
- 1. What are characteristicsof living things? Organisation Response to stimuli Homeostasis (maintaining stable internal conditions), Change through the time… Metabolism Growth and development Reproduction
- 2. CELL STRUCTURE ANDCELLSTRUCTURE AND FUNCTIONSFUNCTIONS
- 3. All living thingsare made of organized parts, obtain energy from their surroundings, perform chemical reactions, respond to their environment, grow and develop, change with time, and reproduce A cell is the smallest unit that can carry on all of the processes of life
- 4. Cell TheoryCell Theory •The cell theory grew out of the work of many scientists and improvements in the microscope. • The cell theory is a unifying concept of biology. • In 1665, Robert Hooke discovered cells in slices of cork. • In 1673, Anton van Leeuwenhoek was the first to observe living cells in microorganisms; Leeuwenhoek called these organism animalcules (now called protists).
- 5. Cell Theory • Allorganisms are made of cells • All cells are produced from other cells (all cells arise from pre-existing cells by cell division) • The cell is the most basic unit of life
- 6. What is acell? How do cells organise in living things?
- 7. Cell Diversity Amoeba Proteus NerveCell Bacteria Plant Stem Red Blood Cell
- 8. All cells sharecertain characteristics • Cells tend to be microscopic • All cells are enclosed by a membrane • All cells are filled with cytoplasm • Unicellular organisms are made up of one cell • Multicellular organisms are made up of many cells that often specialize according to function - differentiation cell membrane cytoplasm
- 9. Cell Size – Cellsize is limited by a cell’s surface area–to-volume ratio.
- 10. Cell size differsamongst species
- 11. Cell Shape – Acell’s shape reflects its function
- 12. Two Types ofCells Prokaryotic cells (without membrane-bound structures) Eukaryotic cells (with membrane-bound structures)
- 14. Prokaryotic cell (‘pro’- before, ‘karyon’ – nucleus)
- 15. Prokarotic cells • Donot have a nucleus and membrane-bound organelles • Have few internal structures • Single, circular chromosome in nucleoid region • Surrounded by cell membrane and a cell wall made up of peptidoglycan • Prokaryotic cells are one-celled organisms: bacteria • Divided into two domains, i.e., Archaea and Bacteria
- 16. Eukaryotic cell (‘eu’- proper, ‘karyon’ – nucleus)
- 17. Eukaryotic cells • Cellshave a nucleus and membrane-bound organelles • Incudes protists, fungi, plants, and animals • The three basic parts of a cell are the plasma membrane, the cytoplasm, and the nucleus.
- 18. Prokaryotic cell Eukaryoticcell Organisms bacteria protists, fungi, plants, animals Size ~ 1-10 µm ~ 10-100 µm Structure • Most have a cell wall and some have a capsule surrounding it • Lack nucleus and many organelles • Ribosomes 70S (50S + 30S) • Only plant cells have cell wall • Has typical nucleus and many organelles • Ribosomes 80S (60S + 40S) Prokaryotic cell vs. Eukaryotic cell
- 19. Virus • No nucleus •No membranes • No organelles • Cannot reproduce on its own • Generally not considered alive by most standards Flu virus
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- 22. A cellA cellis a basic unit of life, that is capable of performing life functions A cell can be likened to a factory
- 23. Each part ofthe cell has their own structure and function
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- 28. Cell Membrane Coverthe cell’s surface Act as a barrier between inside and outside of the cell Controls the transport of materials in and out of the cell
- 29. cell membrane outsidecell inside cell Cell Membrane • Double layer of phospholipids that is highly fluid without breaking. • Embedded proteins in the lipid layer and give the membrane its mosaic character - fluid mosaic. • Selectively permeable protein cholesterol protein carbohydrate chain protein channel
- 30. Phospholipid bilayer • Thefluid portion of the membrane • Phospholipid molecules have: * A polar head group, hydrophilic and points toward the aqueous environment on both sides of the membranes * A pair of nonpolar tails, hydrophobic and point away from the aqueous environments and toward each other
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- 32. Phospholipid bilayer • Establishthe physical integrity of the membrane • Create an effective barrier to the rapid passage of hydrophilic materials such as water and ions • Serves as a lipid “lake” in which a variety of proteins “float” Membranes also contain cholesterol, which is important to membrane integrity and fluidity. Cholesterol prevents the phospholipid from packing tightly together, thus make the cell surface more flexible and stable and prevents freezing in low temperatures
- 33. Membrane Proteins – Cellmembranes often contain proteins embedded within the phospholipid bilayer. – Proteins help move large molecules or aid in cell recognition (peripheral and integral)
- 34. Cell Wall • Mostcommonly found in plant cells & bacteria • Outermost layer of a plant cell (made of cellulose) • Permeable, contains small pores to move water and oxygen and carbon dioxide in and out. • Maintains structure, supports & protects the cell
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- 36. Protoplasm: a clearsubstance like jelly which forms the living part of an animal or plant cell including the nucleus Protoplasm: cytoplasm + nucleus Cytoplasm: cytosol + many organelles Cytoplasm: all the living material in a cell, not including the nucleus Organelle: a membrane-bound structure within a cell which carries out a particular function
- 37. Nucleus • Separate fromcytoplasm by double membrane • Contains genetic material - DNA • Controls all the activities of the cell
- 38. Nuclear Membrane (nuclearenvelope) • Surrounds nucleus • Made of two layers • Pores allowing material to enter and leave nucleus Chromosomes Made of DNA and proteins Contain instructions for traits & characteristics Chromatin condenses to form discrete chromosomes as a cell prepares to divide. Nucleolus The site of ribosomal RNA synthesis
- 39. Cytoplasm • Jelly-like substance •Contains organelles, cytoskeleton, fluid including molecules (proteins, water, food and wastes) • Medium for chemical reaction – Cytosol includes molecules and small particles, such as ribosomes, but not membrane bound organelles. About 20% of the cytosol is made up of protein
- 40. Cytoskeleton • Maintains cellshape and support • Helps position and transport organelles • Provides strength • Assists in cell division • Aids in cell movement
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- 42. Cytoskeleton • Consists ofmicrotubules, microfilaments and intermediate filaments • The microtubules assist in cell division by moving the cells apart. • Microfilaments are made of protein and help with muscle contractions. • Both help support the cell and give structure but do allow for movement.
- 43. Cilia and Flagella •Hairlike structures that extend from the surface of the cell, where they assist in movement • Some cells have flagella. (usually only one) • Many cells have cilia (thousands) • A flagella is like a whip. • Cilia are like tiny paddles. • Cilia and flagella are made of microtubules. Cilia Flagella
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- 45. Endoplasmic Reticulum • Continuouswith the nuclear membrane • Involved in cell product transport of proteins and lipids • The rough and smooth ER are sometimes attach to each other. • Rough ER: surface covered with ribosomes and prepares proteins for export or insertion into the cell membrane. – Most abundant in cells that produce large amounts of protein for export, such as digestive glands and antibody-producing cells
- 46. Endoplasmic Reticulum • SmoothER: lacks ribosomes and makes lipids such as steroids participates in detoxification of toxins. – In ovaries and testes, smooth ER produces estrogen and testosterone, respectively – In skeletal and heart muscle cells, smooth ER releases calcium, which stimulates contraction – Abundant in liver and kidneys for detoxification
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- 48. Ribosomes • Each cellcontains thousands • Float freely in cytoplasm or attached to rough endoplasmic reticulum • Made of protein and rRNA. Ribosome assembly begins in the nucleolus and is completed in the cytoplasm • Site of protein synthesis
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- 50. Golgi Body • Asystem of membranes that work closely with the ER • Consists of flattened membranous sacs called cisternae • Involves in processing, packaging and secreting of proteins/lipids
- 51. cis face (“receiving” sideof Golgi apparatus) trans face (“shipping” side of Golgi apparatus) 0.1 m TEM of Golgi apparatus Cisternae The Golgi apparatus
- 53. Vesicle Vesicles are membrane-boundsacs that hold materials
- 55. Lysosome • Surrounded bysingle membrane • Contains hydrolytic enzyme • Digestive 'plant' for proteins, fats, carbohydrates and nucleic acid as well as old organelles, viruses and bacteria. • Transports undigested material to cell membrane for removal • Cell breaks down if lysosomeLysosomes are rare in plant cells
- 57. Peroxisome • Small organelleswith a single membrane and a granular interior containing specialized enzymes • Collect the toxic peroxides (eg. H2O2) that are the unavoidable by- products of chemical reactions and break them down without mixing with other Glyoxysome, a structurally similar organelle found only in plants especially in young plants, are the sites where stored lipids are converted into carbohydrates for transport to growing cells
- 58. Mitochondrion • Rod-shaped organelle withdouble membrane • Produces energy (ATP) through chemical reactions • Have their own DNA which only comes from the mother.
- 60. Vacuoles • Large andpermanent in plants • Contains sap fluid • Storage areas for cellular products and substances such as water, waste, enzymes and poisons • Help plant cells maintain shape
- 61. Plastid • Plastids storestarch and pigments. – Chloroplasts – contain green pigment, chlorophyll that absorbs light energy to make carbohydrates – Chromoplasts – contain colorful pigments – Amyloplasts – store starch
- 63. Chloroplast • Found onlyin plant cells and some protists • Have double membrane and their own DNA • Contains chlorophyll • Carry out photosynthesis in the presence of sunlight, water and
- 66. Centrioles • Only inanimal cell • Found near nucleus • Tubes found in the centrosomes • Consist of two short cylinders of microtubules at right angles to each other • Involved in cell division • Centrioles form cilia and flagella
- 67. Are plant cellslike animal cells? With the same structure? A typical plant cell has a more regular and rigid shape as compared to a typical animal cell. They contain other organelles that are not found in animal cells such as cell wall, chloroplasts
- 68. Animal Cell andPlant Cell
- 69. Plant Cells Vs.Animal Cells • Contain chloroplasts for photosynthesis • Have a cell wall to maintain structure and rigidity • Centrioles are absent • Usually do not contain lysosomes • Have one large central vacuole • Cells are square and rigid or geometric shaped • No chloroplasts • No cell wall • Centrioles are present • Contain lysosomes • Has small and few vacuoles • Cells are fluid and flexible, many shapes
- 70. 1. Which organellesynthesizes proteins? A. Nucleus B. Ribosome C. Centriole D. All above 2. Most of a cell's ATP is synthesized by membrane-bound organelles called A.Vacuole B. Ribosome C. Mitochondria D. Nucleus 3. Which organelle modifies, packages, and sorts proteins for secretion or use within the cell? A. Mitochondria B. Golgi body C. Nucleus D. Endoplasmic reticulum
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- 75. How big isa cell?
- 76. Kính hiển viquang học Kính hiển vi điện tử Tế bào trứng cá Đa số tế bào thực vật và động vật Lục lạp Đa số vi khuẩn Phage T2 Lipits Proteins Nguyển tử Các phân tử nhỏ Cell size
- 77. The Microscope inCell Studies • 2 different types of microscopes: i) light microscope – uses light as a source of radiation ii) electron microscope – uses electrons UNSWFYBIO/2008JK
- 78. Magnification and Resolution •Magnification - the number of times larger an image is compared with the real size of the object - magnification = size of image actual size of specimen • Resolution - the ability to distinguish between two separate points UNSWFYBIO/2008JK
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- 82. Comparison of advantagesand disadvantages of the light and electron microscope LIGHT MICROSCOPE ELECTRON MICROSCOPE Advantages Disadvantages Cheap to purchase Expensive to purchase Cheap to operate – uses a little electricity where there is a built-in light source Expensive to operate – requires up to 100 000 volts to produce the electric beam Small and portable Very large and must be operated in special rooms Unaffected by magnetic fields Affected by magnetic fields Preparation of material is relatively quick and simple, requiring only a little expertise Preparation of material is lengthy and requires considerable expertise and sometimes complex equipment Material rarely distorted by preparation Preparation of material may distort it Living as well as dead material may be viewed A high vacuum is required and living material cannot be observed Natural colour of material can be observed All images are in black and white Disadvantages Advantages Magnifies objects up to 1500X Magnifies objects over 500 000X Can resolve objects up to 200 nm apart Has a resolving power for biological specimens of around 1 nm The depth of field is restricted It is possible to investigate a greater depth of field