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![Osmosis
• Osmolarity is the concentration of solutes in a solvent
• When solute concentration goes up (high osmolarity),
water concentration goes down, and vice versa
• Water moves by osmosis from areas of low solute [or
high water] (low osmolarity) concentration to high areas
of solute [low water] (high osmolarity) concentration](https://image.slidesharecdn.com/chapter3kfggsqj-250831173441-5db4c8ab/75/chapter_3_Anatomy-and-Physiology-Seeley-s-Edition-24-2048.jpg)
chapter_3_Anatomy and Physiology Seeley's Edition
- 1. Cells: The LivingUnits Raritan Valley Community College Dr. Ahmed Katsha [email protected]
- 2. Disclosure • This courseis using Open Education Resources (OER) mainly from OpenStax. • This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. • Images in these slides are from OpenStax textbook unless otherwise noted. • Text is a mix from OpenStax text and Dr. Ahmed Katsha own explanation.
- 3. Learning Objects – Describethe structure and function of the cell membrane, including its regulation of materials into and out of the cell – Describe the functions of the various cytoplasmic organelles – Explain the structure and contents of the nucleus, as well as the process of DNA replication – Explain the process by which a cell builds proteins using the DNA code – List the stages of the cell cycle in order, including the steps of cell division in somatic cells
- 4. Group discussion 1/4 1.What are the basic parts of cell? 2. What are the functions of the plasma membrane? 3. What does “bi layer” plasma membrane mean? 4. What are the membrane proteins and what do they do?
- 5. Cell theory – Cellsrepresents the basic unit of life. – These tiny fluid-filled sacs house components responsible for the thousands of biochemical reactions necessary for an organism to grow and survive. – Primary responsibility of each cell is to contribute to homeostasis Easy concept
- 6. Cells • Cells sharesimilar structures and functions – Basic parts of human cells: 1. Plasma membrane 2. Cytoplasm 3. Nucleus Easy concept
- 7. Cell Membrane • Thecell membrane consists of two adjacent layers of phospholipids. • A single phospholipid molecule has a phosphate group on one end, called the “head,” and two side-by-side chains of fatty acids that make up the lipid tails • The head is hydrophilic and the tail is hydrophobic Easy concept
- 8. Cell Membrane • Themembrane separates the Intracellular fluid (ICF); the fluid interior of the cell from the Extracellular fluid (ECF), the fluid environment outside. – Phospholipids make 70-75% of the cell mass. • Cell membrane contains 5% glycolipids and 20% cholesterol that stabilize the membrane Easy concept
- 9. Videos • Plasma membrane •https://www.youtube.com/watch?v=moPJkCbKjBs Function of the plasma membrane: 1. Mechanical barrier. 2. Selective permeability. 3. Electrochemical gradient. 4. Communication. 5. Cell signaling.
- 10. Membrane Proteins • Twotypes of proteins • An integral protein is a protein that is embedded in the membrane. – Example : channel protein; selectively allows particular materials, such as certain ions, to pass into or out of the cell. • Peripheral proteins are found on the inner or outer surface of the lipid bilayer and sometimes attached to the internal or external surface of an integral protein. Easy concept
- 11.
- 12. Membrane Proteins functions •Transport • Cell recognition and identification • Receptors and ligands • Anchors for other cellular structures. • Enzymes. • Forming joining areas Easy concept
- 13. Group discussion 2/4 1.What does passive transport mean? 2. What is diffusion? How many types? 3. Does osmosis refer to the movement of solvent or solutes? 4. How many types of tonic solution are there? 5. What are the differences between endocytosis and exocytosis?
- 14. Transport across theCell Membrane • Plasma membrane has selective permeability allows only substances meeting certain criteria to pass through it unaided. – only small, nonpolar materials can move through the lipid bilayer; oxygen and carbon dioxide gases, and alcohol • Two general methods substances move through membrane 1. Passive processes: no energy required. 2. Active processes: energy (ATP) required. Easy concept
- 15. Passive transport ActiveTransport Simple Diffusion Active Transport Facilitated Diffusion Endocytosis Osmosis Exocytosis Two types of membrane transport based on energy use Easy concept
- 16. Passive Membrane Transport •A concentration gradient is the difference in concentration of a substance across a space. • Molecules (or ions) will spread/diffuse from where they are more concentrated to where they are less concentrated until they are equally distributed in that space. – When molecules move in this way, they are said to move down their concentration gradient.
- 17. Diffusion Diffusion is themovement of particles from an area of higher concentration to an area of lower concentration. By CTho at English Wikipedia - Own work. It is/was also available (along with the source images) at http://ctho.ath.cx/pics/new/2006-09-24/, Copyrighted free use, https://commons.wikimedia.org/w/index.php?curid=1353812
- 18. Diffusion • Plasma membranewith its selective permeability feature creates a concentration gradient for certain substances. • Whenever a substance exists in greater concentration on one side of the cell membranes and can cross it, it will diffuse down its concentration gradient. • Damage to plasma membrane disrupts the cell and eventually the homeostasis of the organism.
- 19. Diffusion • Gases suchas oxygen (O2) and CO2 can easily diffuse through the lipid bilayer. • O2 generally diffuses into cells because it is more concentrated outside of them, and CO2 typically diffuses out of cells because it is more concentrated inside of them. • No energy required and therefore it is a passive transport.
- 20. Facilitated Diffusion • Diffusionprocess used for substances that cannot cross the lipid bilayer due to their size, charge, and/or polarity. – Large polar, ionic molecules, charged atoms or molecules • Protein channels and specialized transport mechanisms in the membrane • Facilitated diffusion of substances crossing the cell (plasma) membrane takes place with the help of proteins such as channel proteins and carrier proteins.
- 21. Facilitated Diffusion • Channelproteins are less selective than carrier proteins, and usually mildly discriminate between their cargo based on size and charge. • Some channels are constantly open. Others are opened only when a chemical or electrical signal presents.
- 22. Facilitated Diffusion • Carrierproteins are more selective, often only allowing one particular type of molecule to cross. • Diffusion rate is affected by the number of available carriers. • Sugar, amino acids, Na+ , K+ , Ca++ and many other ions are transported through this mechanism
- 23. Osmosis – The diffusionof water through a semipermeable membrane down its concentration gradient.
- 24. Osmosis • Osmolarity isthe concentration of solutes in a solvent • When solute concentration goes up (high osmolarity), water concentration goes down, and vice versa • Water moves by osmosis from areas of low solute [or high water] (low osmolarity) concentration to high areas of solute [low water] (high osmolarity) concentration
- 25. Videos • Osmosis • https://www.youtube.com/watch?v=w3_8FSrqc-I •https://www.youtube.com/watch?v=SSS3EtKAzYc (nice experiment on eggs) • https://www.youtube.com/watch?v=7-QJ-UUX0iY
- 26. Diffusion Freely permeable membrane Solutes Area oflow osmolarity Area of high osmolarity Solutes particles will diffuse through the membrane to the area of low concentration
- 27. Osmosis Selective permeable membrane Solutes Area oflow osmolarity Area of high osmolarity Since solutes particles cannot diffuse, water will move from area of low osmolarity to high osmolarity. Both areas have same osmolarity now although different water volume
- 28. – Osmosis occurswhen there is an imbalance of solutes outside of a cell versus inside the cell. – Based on osmolarity of two solutions we have three types of solutions: 1. Isotonic solution. 2. Hypertonic solution. 3. Hypotonic solution. Solutions based on Osmolarity
- 29. • Same osmolarityinside and outside the cell. • No net movement of water and therefore no volume change of the cell. Isotonic solution
- 30. • Outside thecell has higher osmolarity than inside cell. • Water leaves the cell, resulting in cell shrinking. Hypertonic solution
- 31. • Outside thecell has lower osmolarity than inside cell. • Water flows into cell, resulting in cell swelling. • Can lead to cell bursting. Hypotonic solution
- 32. Active Membrane Transport •During active transport, ATP is required to move a substance across a membrane, often with the help of protein carriers, and usually against its concentration gradient. • Two forms 1. Active transport through pump 2. Vesicular transport
- 33. Active Transport Pump –ATP changes the shape of the carrier protein and causes ions to bind to it and move against their concertation gradient. – Example of pumps: Na+ /K+ pumps
- 35. Vesicular Transport • Donot involve membrane carriers. • Large particles that don’t usually transported or don’t fit on a carrier. • Requires ATP • Includes : – Endocytosis: transport into cell – Exocytosis: transport out of cell
- 36. Videos • Endocytosis andexocytosis • https://www.youtube.com/watch?v=DuDmvlbpjHQ • https://www.youtube.com/watch?v=lam7btcxnY0 (detailed)
- 37. Endocytosis: bringing “intothe cell” • The process of a cell ingesting material by enveloping it in a portion of its cell membrane, and then pinching off that portion of membrane. • Once pinched off, the portion of membrane and its contents becomes an independent, intracellular vesicle. – A vesicle is a membranous sac—a spherical and hollow organelle bounded by a lipid bilayer membrane. • Phagocytosis (“cell eating”) is the endocytosis by many immune cells of invading pathogens
- 38.
- 39. Exocytosis: taking “outof the cell” • The process of a cell exporting material using vesicular transport • When the vesicle membrane fuses with the cell membrane, the vesicle releases it contents into the interstitial fluid. – The vesicle membrane then becomes part of the cell membrane. – Digestive enzymes and hormones are secreted in this way.
- 40. Membrane Potential (MP) •The separation of ions and other charged particles across plasma membrane creates ions gradient. • The cells tend to maintain the difference between inside and outside resulting in a positive charge on the outer side of the membrane and a negative charge in the inner side of the membrane.
- 41. Membrane Potential (MP) •Cells tend to keep K+ inside. But due to huge difference between inside and outside, K+ escape to outside from leakage channels. • These channels open “randomly” and allows K+ to escape.
- 42. Membrane Potential (MP) •K+ ions can use the leakage channels to get inside the cell as well (attracted to the negative particles on the inner of the cell membrane) • Once the number of K+ leaked outside equals the number of K+ leaked toward inside, the MP is established. • Cells at rest have certain level of MP called the resting MP.
- 43. Group discussion 3/4 1.How many types of cytoplasmic organelles are there? 2. Describe the functions of Mitochondria, Endoplasmic reticulum , Golgi apparatus, Peroxisomes, Lysosomes 3. What is the difference between rough and smooth ER?
- 44. Cytoplasm – Cytosol: thejelly-like substance within the cell, provides the fluid medium necessary for biochemical reactions. – An organelle (“little organ”) is one of several different types of structures in the cell, each performing a unique function. – The organelles and cytosol, taken together, compose the cell’s cytoplasm Easy concept
- 45. Organelles – Some organelleshave a membrane that separate them from the cytosol. These are called membranous organelles. • Example, mitochondria and Golgi apparatus – Others do not have and therefore called non- membranous organelles. • Example, filaments and centrosome Easy concept
- 46. Cytoplasm – A setof three major organelles together form a system within the cell called the endomembrane system. – They work together to perform various cellular jobs, including the task of producing, packaging, and exporting certain cellular products. – The organelles of the endomembrane system include the endoplasmic reticulum, Golgi apparatus, and vesicles. Easy concept
- 47. Endoplasmic Reticulum (ER) •A system of channels that is continuous with the nuclear membrane (or “envelope”) covering the nucleus and composed of the same lipid bilayer material. • The ER provides passages throughout much of the cell that function in transporting, synthesizing, and storing materials. Easy concept
- 48. Endoplasmic Reticulum (ER) •Rough ER (RER) is so called because its membrane is dotted with embedded granules—organelles called ribosomes, giving the RER a bumpy appearance. • Helps in protein synthesis and modification of proteins destined for the cell membrane or for export from the cell Easy concept
- 49. Endoplasmic Reticulum (ER) •Smooth ER (SER) lacks ribosomes and therefore have a smooth surface • Synthesis of lipids, phospholipids, as well as steroid hormones. • Stores and regulates the concentration of cellular Ca++ , a function extremely important in nervous and muscular cells. • The smooth ER additionally metabolizes some carbohydrates and performs a detoxification role, breaking down certain toxins. Easy concept
- 50. Golgi Apparatus • responsiblefor sorting, modifying, and shipping off the products that come from the rough ER. • Also produces lysosomes. Easy concept
- 51. Lysosomes and Peroxisomes •Lysosomes contain digestive enzymes that breakdown several organic compounds. • These organic compounds might be nutrients, defected proteins, bacteria or any materials that need to be broken down and recycled. • Peroxisomes are specialized lysosomes that deal mainly with toxins. Their main function will be detoxification. They are mainly located in liver cells. Easy concept
- 52. Ribosomes • A ribosomeis an organelle that serves as the site of protein synthesis. • It is composed of two ribosomal RNA subunits that wrap around mRNA to start the process of translation, followed by protein synthesis. • They can freely floating within the cell or bind to ER Easy concept
- 53. Mitochondria • Is amembranous, bean-shaped organelle that is the “energy transformer” of the cell. • Muscle and neuron cells are packed full of mitochondria since energy is needed for their functions. Easy concept
- 54. Peroxisomes • a membrane-boundcellular organelle that contains mostly enzymes • Lipid metabolism and chemical detoxification Easy concept
- 55. The Cytoskeleton • Agroup of fibrous proteins that provide structural support for cells. • Cytoskeletal components are also critical for cell motility, cell reproduction, and transportation of substances within the cell. • Three types: 1. Microfilaments 2. Microtubules 3. Intermediate filaments Easy concept
- 56. Centrioles • Two short,identical microtubule structures found near the nucleus of cells • The cellular origin point for microtubules extending outward as cilia or flagella or can assist with the separation of DNA during cell division. Easy concept By Kelvinsong - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=27711468
- 57. Cellular Extensions • Specialcells have structures extending from the cell membrane: • Microvilli are projections that extend from the surface of the small intestine cell to increase surface area. By Boumphreyfr - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=6891773
- 58. Cilia • Cilia arefound on many cells of the body, including the epithelial cells that line the airways of the respiratory system. • Cilia move rhythmically; they beat constantly, moving waste materials such as dust, mucus, and bacteria upward through the airways, away from the lungs and toward the mouth. Blausen.com staff (2014). "Medical gallery of Blausen Medical 2014". WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=28761835
- 59. Flagella • A flagellum(plural = flagella) is an appendage larger than a cilium and specialized for cell locomotion. The only flagellated cell in humans is the sperm cell that must propel itself towards female egg cells. By Mariana Ruiz Villarreal spermatozoa - I did the diagram myself based on the one found on the book "Gray's anatomy" 36th edition, Williams & Warwick, 1980; and a diagram found of the review "Formation and organization of the mammalian sperm head" from Kiyotaka Toshimori and Chizuro Ito. (Chiba, Japan)., Public Domain, https://commons.wikimedia.org/w/index.php? curid=699220
- 60. Nucleus • The nucleusis generally considered the control center of the cell because it stores all of the genetic instructions for manufacturing proteins. • The genetic information is stored within DNA. – Muscle cells, contain more than one nucleus multinucleate and Red blood cells lack the nucleus.
- 61. Structure of theNucleus • The nucleus is surrounded by a membrane called the nuclear envelope with nuclear pores; tiny passageway for the passage of proteins, RNA, and solutes between the nucleus and the cytoplasm. • The nucleolus is a region of the nucleus that is responsible for manufacturing the RNA necessary for construction of ribosomes. Easy concept
- 62. Chromatin • Within thenucleus are threads of chromatin composed of DNA and associated proteins • The chromosome is composed of DNA and proteins; it is the condensed form of chromatin. It is estimated that humans have almost 22,000 genes distributed on 46 chromosomes.
- 63. Videos • Mitosis • https://www.youtube.com/watch?v=L0k-enzoeOM •https://www.youtube.com/watch?v=gwcwSZIfKlM • https://www.youtube.com/watch?v=ofjyw7ARP1c • Protein synthesis • https://www.youtube.com/watch?v=itsb2SqR-R0 • https://www.youtube.com/watch?v=41_Ne5mS2ls • https://www.youtube.com/watch?v=h5mJbP23Buo
- 64. DNA Replication • Inorder for an organism to grow, develop, and maintain its health, cells must reproduce themselves by dividing to produce two new daughter cells, each with the full complement of DNA as found in the original cell. • DNA replication is the copying of DNA that occurs before cell division can take place.
- 65. DNA Replication • Stage1: Initiation. The two complementary strands are untwisted and separated by special enzymes, including helicase. • Stage 2: Elongation. Each strand becomes a template along which a new complementary strand is built. The enzyme DNA polymerase brings in the correct bases to complement the template strand, synthesizing a new strand base by base. This growing strand continues to be built until it has fully complemented the template strand. • Stage 3: Termination. Once the two original strands are bound to their own complementary strands, DNA replication is stopped and the two new identical DNA molecules are complete.
- 66.
- 67. DNA Replication –Each newDNA molecule contains one strand from the original molecule and one newly synthesized strand. The term for this mode of replication is “semiconservative,” because half of the original DNA molecule is conserved in each new DNA molecule.
- 68. Protein Synthesis • Theprocess by which the genetic information in DNA is converted to proteins • Gene is a functional segment of DNA that provides the genetic information necessary to build a protein. • The nucleotide sequence of a gene is ultimately translated into an amino acid sequence of the gene’s corresponding protein.
- 69. Protein Synthesis • Twogeneral processes always in this order: 1. Transcription: happens in nucleus. The genetic code is converted to messenger RNA (mRNA) 2. Translation: happens in cytoplasm. Copy of the genetic code is converted into amino acid sequence (protein) by ribosomes.
- 70. Protein Synthesis in“English” • There is only ONE type of DNA and all the genetic information is saved within it. DNA is valuable and strictly accessible. • In order for the proteins to be produced, the genetic information need to be converted into “less” valuable material. That is the messenger RNA (mRNA). • mRNA represent a copy of the DNA. • mRNA is less valuable, because it can be easily replaced and produced and usually there are hundreds of copies of each gene in form of mRNA.
- 71. Forming mRNA • MessengerRNA (mRNA) – single-stranded nucleic acid that carries a copy of the genetic code for a single gene out of the nucleus and into the cytoplasm where it is used to produce proteins. – RNA polymerase is an enzyme that adds new nucleotides to a growing strand of RNA. This process builds a strand of mRNA. DNA RNA A↔T A↔U C↔G C↔G
- 72. Cell Cycle • Sequenceof events in the life of the cell from the moment it is created at the end of a previous cycle of cell division until it then divides itself, generating two new cells. • Two major periods of cell cycle: 1. Interphase • Interphase is the period of the cell cycle during which the cell is not dividing. 2. Cell division (mitotic phase) • is the division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed.
- 73. Interphase • Can bedivided into three sub- phases: 1. G1 (gap 1): growth phase in the cell cycle and normal cell activities 2. S (synthetic): period during which a cell replicates its DNA. 3. G2 (gap 2): cell continues to grow and makes the necessary preparations for mitosis
- 74. Mitotic Phase • Duringthis phase, a cell undergoes two major processes. • First, it completes mitosis, during which the contents of the nucleus are equitably pulled apart and distributed between its two halves. • Second Cytokinesis; dividing the cytoplasm and cell body into two new cells. – Mitosis is divided into four major stages that take place after interphase 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase
- 75. Cell Division-Prophase • Firstphase of mitosis. The chromatin coils and condenses into visible chromosomes. • The nuclear envelope disintegrates • The cell contains two centrosomes side- by-side, which begin to move apart. • Microtubules begin to extend from each centrosome toward the other forming the mitotic spindle. • Microtubules attach themselves to the centromeres that adjoin pairs of sister chromatids.
- 76. Cell Division-Metaphase • Secondstage of mitosis. • the sister chromatids, with their attached microtubules, line up along a linear plane in the middle of the cell. • A metaphase plate forms between the centrosomes that are now located at either end of the cell. • The microtubules are now poised to pull apart the sister chromatids and bring one from each pair to each side of the cell.
- 77. Cell Division-Anaphase • Thirdstage of mitosis. Very fast • The pairs of sister chromatids are separated from one another, forming individual chromosomes • The chromosomes are pulled to opposite ends of the cell • Each end of the cell receives one partner from each pair of sister chromatids, ensuring that the two new daughter cells will contain identical genetic material.
- 78. Cell Division-Telophase • Finalstage of mitosis. • Two new daughter nuclei at either end of the dividing cell form. • The mitotic spindle breaks. • Each end of the cell receives one partner from each pair of sister. • Each new cell receiving its own complement of DNA, organelles, membranes, and centrioles. • The cell is already beginning to split in half as cytokinesis begins.
- 79. Cell division-Cytokinesis • Formationof the cleavage furrow. • A contractile band made up of microfilaments that forms around the midline of the cell during cytokinesis . • It squeezes the two cells apart until they finally separate.
- 80.
Editor's Notes
- #28 Video from youtube eggs and water.