Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
The Cell
Antoni  van  Leeuwenhoek <ul><ul><li>(1632-1723), Dutch, maker of first  single  lens  microscope </li></ul></ul><ul><ul><...
Types  of  Microscopes <ul><ul><ul><li>1.  COMPOUND/LIGHT MICROSCOPE </li></ul></ul></ul><ul><ul><ul><li>Principle: sunlig...
 
 
Image under Compound  microscope Scanning  EM Transmission  EM
CELL <ul><li>Robert  Hooke   (1665)  =  studied the cork & other plant materials    many small partitions separating </li...
Cell Diversity <ul><li>Cells that connect body parts </li></ul><ul><li>Cells that cover and line body organs </li></ul><ul...
3 Main Parts <ul><li>1. PLASMA MEMBRANE </li></ul><ul><li>2. CYTOPLASM </li></ul><ul><li>3. NUCLEUS </li></ul>
1. Plasma Membrane <ul><li>syn:  plasmalemma, cell membrane </li></ul><ul><li>- outer covering of the cell </li></ul><ul><...
Plasma Membrane <ul><li>some, cholesterol and glycolipids </li></ul><ul><li>LIPID BILAYER + integral and peripheral protei...
Plasma Membrane <ul><li>Impermeable to: ions, glucose, a.a. </li></ul><ul><li>transport assisted by: ion channels, transpo...
Plasma Membrane
rane
Definition of Terms <ul><li>Intracellular fluid (ICF)  – inside body cells i.e. fluid in cytoplasm, 2/3 of body fluid  </l...
Definition of Terms <ul><li>Solute – any material dissolved in a fluid </li></ul><ul><li>Solvent – fluid in w/c the solute...
Definition of Terms <ul><li>CONCENTRATION  – the amount of a solute in a solution </li></ul><ul><li>CONCENTRATION GRADIENT...
Substances move across cellular membranes by: <ul><li>PASSIVE PROCESSES  – substance moves down its concentration gradient...
Passive Processes <ul><li>DIFFUSION  – a substance moves from one place to another due to the substance's kinetic energy  ...
Diffusion
2 Types of Diffusion <ul><li>1. SIMPLE DIFFUSION  </li></ul><ul><ul><li>lipid-soluble substances diffuse through the lipid...
Simple Diffusion
2 Types of Diffusion <ul><li>1. SIMPLE DIFFUSION  </li></ul><ul><ul><li>Ion channels – allow a specific type of ion to mov...
 
2 Types of Diffusion <ul><li>2. FACILITATED DIFFUSION  </li></ul><ul><ul><li>an integral membrane protein assists a specif...
 
Passive Processes 2.  OSMOSIS  = net movement of water through a selectively permeable membrane - water moves from an area...
Osmosis
EFFECT  of  OSMOSIS  in  CELLS ISOTONIC   = any solution in w/c cells maintain their normal shape and volume, concentratio...
Effects of Osmosis
Passive Processes 3. FILTRATION  = process by w/c H2O and solutes are forced through a membrane (or capillary wall) by  fl...
Active Processes 1.  ACTIVE TRANSPORT   - cellular energy is used to transport substances across the membrane against a co...
Active Transport
Active Processes 2.  TRANSPORT IN VESICLES  - VESICLE   –  small round sac formed by budding off from an existing membrane...
2 Types of Transport in Vesicles 1. ENDOCYTOSIS –   materials move into a cell in a vesicle formed from the plasma membran...
<ul><li>1. PHAGOCYTOSIS –   large solid particles (e.g. bacteria, viruses, aged or dead cells), are taken in by the cell  ...
<ul><li>2. BULK-PHASE ENDOCYTOSIS (PINOCYTOSIS) –   cells take up tiny droplets of ECF  </li></ul><ul><li>- fuses with a l...
2 Types of Transport in Vesicles 2. EXOCYTOSIS   – results in secretion (release of materials from a cell) a. SECRETORY CE...
Exocytosis
Table. 3.2
Specializations of the Plasma Membrane <ul><li>Microvilli </li></ul><ul><li>Membrane junctions </li></ul>
Membrane Junctions <ul><li>1. TIGHT JUNCTIONS  = formed from fusion of adjacent cell membrane --> impermeable or leak-proo...
2. Cytoplasm <ul><li>consists of all cellular contents bet. the cell membrane and nucleus </li></ul><ul><li>Includes:   </...
1. Cytoskeleton <ul><li>network of 3 different types of protein filaments </li></ul><ul><li>1. MICROFILAMENTS  – thinnest,...
1. Cytoskeleton 2. INTERMEDIATE FILAMENTS   – found in parts of cells subject to tension (stretching), hold organelles in ...
 
<ul><li>found near the nucleus </li></ul><ul><li>Includes: </li></ul><ul><li>1. Centrioles (paired) – composed of microtub...
3. Cilia and Flagella <ul><li>CILIA  – short, hairlike projections extending from the surface of the cell </li></ul><ul><u...
4. Ribosomes <ul><li>Tiny, round, dark bodies </li></ul><ul><li>Actual site of protein production </li></ul><ul><li>high r...
5. Endoplasmic Reticulum (ER) <ul><li>network of folded membranes  </li></ul><ul><li>2 Types </li></ul><ul><li>Rough ER   ...
5. Endoplasmic Reticulum (ER)
6. Golgi Complex <ul><li>Stack of flattened membranous sacs </li></ul><ul><li>Modify and package proteins </li></ul><ul><u...
 
7. Lysosomes <ul><li>membrane-encosed vesicles, >/= 60 digestive enzymes </li></ul><ul><li>digestion, recycling </li></ul>...
 
8. Peroxisomes <ul><li>Sacs containing oxidase enzymes </li></ul><ul><li>Use oxygen to detoxify harmful or poisonous subst...
9. Proteasomes <ul><li>continuous destruction of unneeded , damaged or faulty proteins  </li></ul><ul><li>contain protease...
10. Mitochondria <ul><li>powerhouse of the cell (site of ATP production) </li></ul><ul><li>increased in: muscles, liver, k...
3. Nucleus <ul><li>most prominent feature of a cell </li></ul><ul><li>NUCLEAR ENVELOPE – separates the nucleus from the cy...
3. Nucleus <ul><li>GENES  – hereditary units </li></ul><ul><ul><li>direct cellular activities  </li></ul></ul><ul><ul><li>...
 
 
 
Protein Synthesis <ul><li>DNA found in genes gives instructions for making proteins </li></ul><ul><li>1. Transcription – D...
Transcription <ul><li>occurs in the nucleus </li></ul><ul><li>genetic info in DNA  base triplets  is copied into complemen...
3 Kinds of RNA <ul><li>1.  Messenger RNA  (mRNA )  – directs synthesis of a protein </li></ul><ul><li>2.  Ribosomal RNA  (...
Base pairing
Translation <ul><li>mRNA attaches to ribosomes and directs protein synthesis by converting sequence of nucleotides (CODON)...
 
Somatic Cell Division <ul><li>process by which damaged, diseased or worn out cells are replaced </li></ul><ul><li>process ...
2 Types of Cell Division <ul><li>1. REPRODUCTIVE CELL DIVISION (MEIOSIS) </li></ul><ul><li>- the process that produces gam...
Prerequisite of somatic cell division: DNA Replication  <ul><li>DNA – building blocks  “nucleotides” </li></ul><ul><ul><li...
<ul><li>duplication of the DNA sequences that make up the genes and chromosomes --> daughter cells w/ same genes and same ...
DNA Replication
Cell Cycle <ul><li>sequence of changes that a cell undergoes from the time it forms until it duplicates its contents and d...
<ul><li>DNA replication occurs </li></ul><ul><li>manufactures organelles and cytosolic components </li></ul><ul><li>increa...
Mitotic Phase <ul><li>consists of: </li></ul><ul><li>MITOSIS  – nuclear division </li></ul><ul><li>CYTOKINESIS  – cytoplas...
<ul><li>PROPHASE   =  chromatin coil and shorten   chromosomes,  bar-like bodies </li></ul><ul><ul><li>Chromosome = 2 str...
<ul><li>Mitosis </li></ul><ul><li>STAGES : </li></ul><ul><li>METAPHASE  – chromosomes cluster and align  at the center (me...
<ul><li>Mitosis </li></ul><ul><li>STAGES: </li></ul><ul><li>ANAPHASE   –  movement of chromosomes toward    opposite ends ...
<ul><li>Mitosis </li></ul><ul><li>STAGES: </li></ul><ul><li>TELOPHASE   –  chromosomes uncoil and become  chromatin again,...
Cytokinesis <ul><li>division of a cell's cytoplasm and organelles </li></ul><ul><li>formation of cleavage furrow that exte...
 
END <ul><li>QUIZ NEXT MEETING! </li></ul>
Upcoming SlideShare
Loading in …5
×

Cell

883 views

Published on

Published in: Technology
  • Be the first to comment

  • Be the first to like this

Cell

  1. 1. The Cell
  2. 2. Antoni van Leeuwenhoek <ul><ul><li>(1632-1723), Dutch, maker of first single lens microscope </li></ul></ul><ul><ul><li>The first to document the structure of RBC & the nature of the circulatory system </li></ul></ul><ul><ul><li>protozoans & bacteria, life cycles of many species of insects. </li></ul></ul><ul><ul><li>MICROMETER ( µ m) = 1/1000 </li></ul></ul>
  3. 3. Types of Microscopes <ul><ul><ul><li>1. COMPOUND/LIGHT MICROSCOPE </li></ul></ul></ul><ul><ul><ul><li>Principle: sunlight (light source) </li></ul></ul></ul><ul><ul><ul><li>2. ELECTRON MICROSCOPE </li></ul></ul></ul><ul><ul><ul><li>Principle: beam of electrons </li></ul></ul></ul><ul><ul><li>a. Transmission (magnification: >/=1Mx) </li></ul></ul><ul><ul><li>b. Scanning – 3D image <250,000x </li></ul></ul><ul><ul><li>Magnification = extent to which an image is enlarged </li></ul></ul>
  4. 6. Image under Compound microscope Scanning EM Transmission EM
  5. 7. CELL <ul><li>Robert Hooke (1665) = studied the cork & other plant materials  many small partitions separating </li></ul><ul><li>cavities  cells. </li></ul><ul><li>Basic structural and functional units of an organism </li></ul><ul><li>Carry out all chemical activities </li></ul><ul><li>needed to sustain life </li></ul>
  6. 8. Cell Diversity <ul><li>Cells that connect body parts </li></ul><ul><li>Cells that cover and line body organs </li></ul><ul><li>Cells that move organs and body parts </li></ul><ul><li>Cell that stores nutrients </li></ul><ul><li>Cell that fights disease </li></ul><ul><li>Cell that gathers information and controls body functions </li></ul><ul><li>Cells of reproduction </li></ul>
  7. 9. 3 Main Parts <ul><li>1. PLASMA MEMBRANE </li></ul><ul><li>2. CYTOPLASM </li></ul><ul><li>3. NUCLEUS </li></ul>
  8. 10. 1. Plasma Membrane <ul><li>syn: plasmalemma, cell membrane </li></ul><ul><li>- outer covering of the cell </li></ul><ul><li>- surrounds each cell  separate its contents from external environment </li></ul><ul><li>- regulates what enters & leaves the cell </li></ul><ul><li>- allows communication </li></ul>
  9. 11. Plasma Membrane <ul><li>some, cholesterol and glycolipids </li></ul><ul><li>LIPID BILAYER + integral and peripheral proteins </li></ul><ul><li>SELECTIVE PERMEABILITY </li></ul><ul><ul><li>- water & nonpolar (lipid-soluble) molecules e.g. FA, fat-soluble vit., steroids, O2, CO2 </li></ul></ul><ul><li>mainly made up of phospholipids and proteins (latter, mainly glycoproteins) </li></ul>
  10. 12. Plasma Membrane <ul><li>Impermeable to: ions, glucose, a.a. </li></ul><ul><li>transport assisted by: ion channels, transporters </li></ul><ul><li>Integral proteins act as: receptors, enzymes, cell identity markers </li></ul>
  11. 13. Plasma Membrane
  12. 14. rane
  13. 15. Definition of Terms <ul><li>Intracellular fluid (ICF) – inside body cells i.e. fluid in cytoplasm, 2/3 of body fluid </li></ul><ul><li>Extracellular fluid (ECF) – fluid outside body cells </li></ul><ul><li>Interstitial fluid – the ECF between cells </li></ul><ul><ul><li>e.g. plasma (in blood vessels), lymph (in lymphatic vessels) </li></ul></ul><ul><ul><li>** materials dissolved in body fluids: gases, nutrients, ions, etc. </li></ul></ul>
  14. 16. Definition of Terms <ul><li>Solute – any material dissolved in a fluid </li></ul><ul><li>Solvent – fluid in w/c the solute is dissolved e.g. water </li></ul><ul><li>Solution – homogenous mixture of 2 or more components (e.g. air, seawater, alcohol) </li></ul>
  15. 17. Definition of Terms <ul><li>CONCENTRATION – the amount of a solute in a solution </li></ul><ul><li>CONCENTRATION GRADIENT – difference in concentration between 2 different areas </li></ul><ul><ul><li>moving down vs. moving up </li></ul></ul>
  16. 18. Substances move across cellular membranes by: <ul><li>PASSIVE PROCESSES – substance moves down its concentration gradient using only its own energy of motion (kinetic energy) </li></ul><ul><ul><li>SIMPLE DIFFUSION, OSMOSIS </li></ul></ul><ul><li>ACTIVE PROCESSES – cellular energy (e.g. ATP) is used to push the substance through the membrane against its concentration gradient </li></ul><ul><ul><li>ACTIVE TRANSPORT, VESICLES </li></ul></ul>
  17. 19. Passive Processes <ul><li>DIFFUSION – a substance moves from one place to another due to the substance's kinetic energy </li></ul><ul><ul><ul><li>particles move from a region of higher to lower concentration </li></ul></ul></ul><ul><ul><ul><li>endpoint: EQUILIBRIUM – substance is evenly distributed throughout the solution and the concentration gradient disappears </li></ul></ul></ul><ul><ul><ul><li>may or may not involve a membrane </li></ul></ul></ul>
  18. 20. Diffusion
  19. 21. 2 Types of Diffusion <ul><li>1. SIMPLE DIFFUSION </li></ul><ul><ul><li>lipid-soluble substances diffuse through the lipid bilayer e.g. O2, CO2, N, f.a., steroids, vit. ADEK, H2O, urea </li></ul></ul><ul><ul><li>used in: exchange of gases, absorption of nutrients, release of wastes </li></ul></ul>
  20. 22. Simple Diffusion
  21. 23. 2 Types of Diffusion <ul><li>1. SIMPLE DIFFUSION </li></ul><ul><ul><li>Ion channels – allow a specific type of ion to move across the membrane through the channel's pore </li></ul></ul><ul><ul><li>e.g. K, Cl, Na, Ca </li></ul></ul>
  22. 25. 2 Types of Diffusion <ul><li>2. FACILITATED DIFFUSION </li></ul><ul><ul><li>an integral membrane protein assists a specific substance across the membrane </li></ul></ul><ul><ul><li>substance binds to a specific TRANSPORTER on one side of the membrane --> released on the other side after the transporter undergoes a change in shape </li></ul></ul><ul><ul><li>movement along a conc. gradient, NO ATP needed </li></ul></ul><ul><ul><li>e.g. glucose, fructose, galactose </li></ul></ul>
  23. 27. Passive Processes 2. OSMOSIS = net movement of water through a selectively permeable membrane - water moves from an area of higher water to an area of lower water concentration - or, from an area of lower solute concentration to an area of higher solute concentration OSMOTIC PRESSURE – depends on the concentration of its solute particles - the higher the solute conc., the higher the osmotic pressure
  24. 28. Osmosis
  25. 29. EFFECT of OSMOSIS in CELLS ISOTONIC = any solution in w/c cells maintain their normal shape and volume, concentrations of solutes are same on both sides = tissue fluids, blood plasma, 0.9% NSS, 5% dextrose (glucose) HYPOTONIC = lower concentration of solutes (higher conc. of H2O) than the cytosol inside the cell = cell swells --> ruptures HYPERTONIC = higher concentration of solutes (lower conc. of water) than the cytosol inside the cell = cell shrinks
  26. 30. Effects of Osmosis
  27. 31. Passive Processes 3. FILTRATION = process by w/c H2O and solutes are forced through a membrane (or capillary wall) by fluid or hydrostatic pressure (pressure gradient) e.g. filtering capacity of the kidney (e.g. in urine formation)
  28. 32. Active Processes 1. ACTIVE TRANSPORT - cellular energy is used to transport substances across the membrane against a concentration gradient (from an area of low to an area of high concentration), needs ATP - splitting of ATP changes the shape of a transporter protein (PUMP) --> moves a substance across the membrane against its conc. gradient - Na, K, H, Ca, I, Cl
  29. 33. Active Transport
  30. 34. Active Processes 2. TRANSPORT IN VESICLES - VESICLE – small round sac formed by budding off from an existing membrane - transport substances, take in and release substances - requires energy (ATP)
  31. 35. 2 Types of Transport in Vesicles 1. ENDOCYTOSIS – materials move into a cell in a vesicle formed from the plasma membrane - substances are surrounded by a piece of the plasma membrane w/c buds off inside the cell to form a vesicle containing the ingested substances.
  32. 36. <ul><li>1. PHAGOCYTOSIS – large solid particles (e.g. bacteria, viruses, aged or dead cells), are taken in by the cell </li></ul><ul><li>- fuses w/ a lysosome --> break down of material </li></ul><ul><li>- e.g. WBCs, macrophages </li></ul>2 Types of Endocytosis
  33. 37. <ul><li>2. BULK-PHASE ENDOCYTOSIS (PINOCYTOSIS) – cells take up tiny droplets of ECF </li></ul><ul><li>- fuses with a lysosome --> enzymatic breakdown of engulfed solutes </li></ul>2 Types of Endocytosis
  34. 38. 2 Types of Transport in Vesicles 2. EXOCYTOSIS – results in secretion (release of materials from a cell) a. SECRETORY CELLS – release digestive enzymes, hormones, mucus, etc. b. NERVE CELLS – during release of neurotransmitters * membrane-enclosed secretory vesicles form inside the cell, fuse w/ the cell membrane, and release contents into the ECF
  35. 39. Exocytosis
  36. 40. Table. 3.2
  37. 41. Specializations of the Plasma Membrane <ul><li>Microvilli </li></ul><ul><li>Membrane junctions </li></ul>
  38. 42. Membrane Junctions <ul><li>1. TIGHT JUNCTIONS = formed from fusion of adjacent cell membrane --> impermeable or leak-proof sheets </li></ul><ul><ul><li>= keep digestive juices & harmful substances from damaging the organs or getting into the bloodstream </li></ul></ul><ul><li>2. DESMOSOMES = anchoring junctions (button-like thickenings), prevent cells under mechanical stress from being pulled apart e.g. skin </li></ul><ul><li>3. GAP JUNCTIONS = allows communication e.g. heart, nervous system </li></ul>
  39. 43. 2. Cytoplasm <ul><li>consists of all cellular contents bet. the cell membrane and nucleus </li></ul><ul><li>Includes: </li></ul><ul><ul><li>CYTOSOL (ICF) – fluid portion of the cytoplasm, 55% of total cell volume, 75-90% H2O, site of chemical reactions </li></ul></ul><ul><ul><li>ORGANELLES – specialized structures inside cells w/ specific functions </li></ul></ul>
  40. 44. 1. Cytoskeleton <ul><li>network of 3 different types of protein filaments </li></ul><ul><li>1. MICROFILAMENTS – thinnest, concentrated at the periphery --> strength and shape </li></ul><ul><li>- provides mechanical support and generates movement </li></ul><ul><li>- anchor cytoskeleton to integral proteins </li></ul><ul><li>- support for microvilli </li></ul><ul><li>- intercellular attachment </li></ul>
  41. 45. 1. Cytoskeleton 2. INTERMEDIATE FILAMENTS – found in parts of cells subject to tension (stretching), hold organelles in place, intercellular attachment 3. MICROTUBULES – long, hollow tubes, determines cell shape, movement of organelles w/in the cell, migration of chromosomes during cell division, movement of cilia and flagella
  42. 47. <ul><li>found near the nucleus </li></ul><ul><li>Includes: </li></ul><ul><li>1. Centrioles (paired) – composed of microtubules </li></ul><ul><li>2. Pericentriolar material – composed of tubulins, organizing centers for growth of the mitotic spindle (role in cell division) </li></ul>2 . Centrosome
  43. 48. 3. Cilia and Flagella <ul><li>CILIA – short, hairlike projections extending from the surface of the cell </li></ul><ul><ul><li>propel fluids across surfaces of cells </li></ul></ul><ul><li>FLAGELLA - move an entire cell </li></ul>
  44. 49. 4. Ribosomes <ul><li>Tiny, round, dark bodies </li></ul><ul><li>Actual site of protein production </li></ul><ul><li>high rRNA content </li></ul><ul><ul><li>Free ribosomes </li></ul></ul><ul><ul><li>attached to RER </li></ul></ul>
  45. 50. 5. Endoplasmic Reticulum (ER) <ul><li>network of folded membranes </li></ul><ul><li>2 Types </li></ul><ul><li>Rough ER – extends from the nuclear envelope, studded w/ ribosomes, synthesis of secretory proteins and membrane molecules </li></ul><ul><li>Smooth ER – extends from the RER --> network of membranous tubules, lacks ribosomes, f.a. & steroids (e.g. estrogen, testosterone) are produced, detoxification (e.g. alc, pesticides, carcinogens) </li></ul>
  46. 51. 5. Endoplasmic Reticulum (ER)
  47. 52. 6. Golgi Complex <ul><li>Stack of flattened membranous sacs </li></ul><ul><li>Modify and package proteins </li></ul><ul><ul><li>secretory vesicles </li></ul></ul><ul><ul><li>carries proteins and phospholipids to become part of cell membrane </li></ul></ul><ul><ul><li>incorporated in lysosomes </li></ul></ul>
  48. 54. 7. Lysosomes <ul><li>membrane-encosed vesicles, >/= 60 digestive enzymes </li></ul><ul><li>digestion, recycling </li></ul><ul><li>autophagy, autolysis </li></ul>
  49. 56. 8. Peroxisomes <ul><li>Sacs containing oxidase enzymes </li></ul><ul><li>Use oxygen to detoxify harmful or poisonous substances (e.g. alcohol, formaldehyde) </li></ul><ul><li>Disarm “free radicals” </li></ul><ul><ul><li>FR -> H2O2->H2O </li></ul></ul><ul><ul><li>liver and kidney cells </li></ul></ul>
  50. 57. 9. Proteasomes <ul><li>continuous destruction of unneeded , damaged or faulty proteins </li></ul><ul><li>contain proteases </li></ul>
  51. 58. 10. Mitochondria <ul><li>powerhouse of the cell (site of ATP production) </li></ul><ul><li>increased in: muscles, liver, kidneys </li></ul>
  52. 59. 3. Nucleus <ul><li>most prominent feature of a cell </li></ul><ul><li>NUCLEAR ENVELOPE – separates the nucleus from the cytoplasm </li></ul><ul><li>NUCLEAR PORES – control movement of substances </li></ul><ul><li>NUCLEOLI – sites of assembly of ribosomes </li></ul>
  53. 60. 3. Nucleus <ul><li>GENES – hereditary units </li></ul><ul><ul><li>direct cellular activities </li></ul></ul><ul><ul><li>arranged along chromosomes </li></ul></ul><ul><ul><ul><li>46 chromosomes (23/parent) </li></ul></ul></ul><ul><ul><ul><li>in a nondividing cell, chromosomes appear as diffuse granular mass --> CHROMATIN </li></ul></ul></ul><ul><li>GENOME – total genetic information carried in a cell or organism </li></ul>
  54. 64. Protein Synthesis <ul><li>DNA found in genes gives instructions for making proteins </li></ul><ul><li>1. Transcription – DNA is copied --> RNA </li></ul><ul><li>2. Translation – information in RNA (attached to a ribosome) is translated into a sequence of a.a. --> protein molecule </li></ul>
  55. 65. Transcription <ul><li>occurs in the nucleus </li></ul><ul><li>genetic info in DNA base triplets is copied into complementary sequence of CODONS in a strand of RNA (helped by RNA polymerase) </li></ul><ul><li>PROMOTER – sequence of nucleotides in DNA where RNA polymerase attaches to </li></ul><ul><li>TERMINATOR – sequence of nucleotides in DNA where transcription ends </li></ul>
  56. 66. 3 Kinds of RNA <ul><li>1. Messenger RNA (mRNA ) – directs synthesis of a protein </li></ul><ul><li>2. Ribosomal RNA (rRNA) – joins w/ ribosomal proteins to make ribosomes </li></ul><ul><li>3. Transfer RNA (tRNA) – binds to an a.a. and holds it in place on a ribosome until it becomes part of a protein during translation </li></ul>
  57. 67. Base pairing
  58. 68. Translation <ul><li>mRNA attaches to ribosomes and directs protein synthesis by converting sequence of nucleotides (CODON) into a specific sequence of a.a. --> PROTEIN </li></ul><ul><li>tRNA contains the triplet of nucleotides called ANTICODON </li></ul><ul><li>Protein synthesis ends when ribosome reaches a STOP CODON </li></ul><ul><li>15 a.a./second </li></ul>
  59. 70. Somatic Cell Division <ul><li>process by which damaged, diseased or worn out cells are replaced </li></ul><ul><li>process by which cells reproduce themselves </li></ul>
  60. 71. 2 Types of Cell Division <ul><li>1. REPRODUCTIVE CELL DIVISION (MEIOSIS) </li></ul><ul><li>- the process that produces gametes (sperm & oocytes) </li></ul><ul><li>2. SOMATIC CELL DIVISION </li></ul><ul><li>- division of all body cells (except gametes) --> two identical cells </li></ul>
  61. 72. Prerequisite of somatic cell division: DNA Replication <ul><li>DNA – building blocks “nucleotides” </li></ul><ul><ul><li>Deoxyribose sugar </li></ul></ul><ul><ul><li>Phosphate group </li></ul></ul><ul><ul><li>Nitrogen-containing base </li></ul></ul>
  62. 73. <ul><li>duplication of the DNA sequences that make up the genes and chromosomes --> daughter cells w/ same genes and same number of chromosomes </li></ul>Prerequisite of somatic cell division: DNA Replication
  63. 74. DNA Replication
  64. 75. Cell Cycle <ul><li>sequence of changes that a cell undergoes from the time it forms until it duplicates its contents and divides into two cells </li></ul><ul><li>2 MAJOR PERIODS </li></ul><ul><li>1. INTERPHASE – cell is not dividing </li></ul><ul><li>2. MITOTIC PHASE – cell is dividing </li></ul>
  65. 76. <ul><li>DNA replication occurs </li></ul><ul><li>manufactures organelles and cytosolic components </li></ul><ul><li>increased metabolic activity </li></ul><ul><li>cell is growing </li></ul>Interphase
  66. 77. Mitotic Phase <ul><li>consists of: </li></ul><ul><li>MITOSIS – nuclear division </li></ul><ul><li>CYTOKINESIS – cytoplasmic division into 2 cells </li></ul>
  67. 78. <ul><li>PROPHASE = chromatin coil and shorten  chromosomes, bar-like bodies </li></ul><ul><ul><li>Chromosome = 2 strands of chromatids , held together by a buttonlike body, centromere </li></ul></ul>Mitosis
  68. 79. <ul><li>Mitosis </li></ul><ul><li>STAGES : </li></ul><ul><li>METAPHASE – chromosomes cluster and align at the center (metaphase plate) </li></ul>
  69. 80. <ul><li>Mitosis </li></ul><ul><li>STAGES: </li></ul><ul><li>ANAPHASE – movement of chromosomes toward opposite ends of the cell </li></ul>
  70. 81. <ul><li>Mitosis </li></ul><ul><li>STAGES: </li></ul><ul><li>TELOPHASE – chromosomes uncoil and become chromatin again, nuclear envelope forms around each chromatin mass </li></ul>
  71. 82. Cytokinesis <ul><li>division of a cell's cytoplasm and organelles </li></ul><ul><li>formation of cleavage furrow that extends around the center of the cell </li></ul><ul><li>endpoint: 2 new and separate cells </li></ul>
  72. 84. END <ul><li>QUIZ NEXT MEETING! </li></ul>

×