Cell Structure and Function PDF

Introduction to Cells Session Learning Outcomes (SLOs) SLO# 1: Explain the cell theory and the basic cell structure SLO# 2: Compare the structure of a prokaryotic cell with the structure of a eukaryotic cell SLO# 3: Explain how cell fractionation is used to isolate the cell components. SLO# 1:...

Introduction to Cells Session Learning Outcomes (SLOs) SLO# 1: Explain the cell theory and the basic cell structure SLO# 2: Compare the structure of a prokaryotic cell with the structure of a eukaryotic cell SLO# 3: Explain how cell fractionation is used to isolate the cell components. SLO# 1: Recognize organelles found in eukaryotic cells. SLO# 2: Identify the function and organization of the various organelles in eukaryotic cells. SLO# 3: Explain how the diseases are associated with specific cell-organelles.  chemical Cell Theory Leyer Ei 1- Cells are the smallest ftp 4emieverAorganismgee structural and functional unit of organisms 2- All organisms are composed of cells en en 3- All cells come only from preexisting cells (Cell division)  Characteristics of a Cell or cell functions Store information in the DNA Make and Use energy Mitrochinaria Capable of movement Sense environmental changes byresepters andresponse to them Can duplicate (growth, repair, reproduction & development) in what is selfregulation homeosta cells Capable of self-regulation (homeostasis) status corigina retinabitt to 9 EEtgt.fi nng30oYetn Build molecules (proteins, carbohydrates, fats, nucleic acids) Types of cells Prokaryot an organism consisting of a cell or cells in e cause they don'thave a thereDNA hack anovertheis which the genetic material is DNA in the form of chromosomes contained within a place distinct nucleus sniff SIT Eukaryotes Bacteria cells to i Animal cells Plant cells  Prokaryotes vs. Eukaryotes Prokaryotic Bacteria Eukaryotic Cells archaea Cells > 10 µm Size 10-100 µm midro Does not have a true Nucleus Has a true membrane nucleus. Only a nucleoid bound nucleus thetethleusonly Has no membrane bound Membrane Has membrane bound organelles IG bound Organelles organelles DID I s sight side One circular piece of DNA DNA Many linear pieces of with no proteins only one chromsom DNA with proteins DNAcan'tform Small ribosomes Ribosomes Large ribosomes All Prokaryotes are past.mn hoatf Number of cells Eukaryotes are either unicellular Wi Te unicellular or onesingle cell multicellular Asexual only through Reproduction Sexual and asexual binary fission through mitosis & meiosis if the bectrica Fya has the same  Three important Cell Regions dis days Facesia 1- Cell membrane: 2- Nucleus I This is the outermost The control center of the cell boundary on the cell. that contains the DNA (deoxyribonucleic acid) which directs the functioning of the cytoplasm cell. Nucleus cell membrane 3- Cytoplasm: The part between the cell membrane and the nucleus It contains a liquid called cytosol. Within the cytosol are organelles which are special structures that carry out different cell functions.  Three important Cell Regions As well, two other important terms are: 1- Intracellular which refers to the area inside of the cell. intracellular Extracellular 2- Extracellular which refers to the area outside of the cell.  Why study cells? after form Cells Tissues Organs Bodies tissue Bodies are made up of cells. Cells do all the work of life.  904 do we have this study 7 How study cells? a 99 Ans We study cells using biochemistry techniques. 125 Cell fractionation if the to spreate the commberants cells to Js - Isolating organelles w.CI - Homogenization s Soul slot - Ultracentrifugation The bigger the Cell Fractionation organelles thefaster Jescasapartandseparates Testitments to themajororganelles APPLICATION: shea andother n'Shestructures from Fractionate cell components based on size and density. IT c lysoms TECHNIQUE: different metgandri FEe.atatshort Cells are homogenized in a blender. she is high The resulting homogenate is centrifuged.sting tEitsne ask Differential centrifugation results in a series of pellets, each containing different cell about numbers components Bits RESULTS: Tolerating Using microscopy to identify the organelles in each pellet Using biochemical methods to determine the metabolic functions of the organelles.  Organelles in eukaryotic cells The Cell Membrane consider Structure as a The cell membrane is also known as the orgneebe plasma membrane. 6 It is composed of two layers of phospholopids. II because it is made of these two layers It is called the phospholipids bilayer hydrobilic A phospholipid is a type of fat composed of: in Aqueous environment Phosphate 1- A hydrophilic “water-loving” phosphate head outside head that faces the aqueous environment. Fatty see F 2- Two hydrophobic water-fearing” fatty acid c acid tails inside tails which face other fatty acid tails erea Aqueous environment com'bani n The Cell Membrane Structure of diff muleculs o iftem.PT tsyreg arop theTfunction can Besides the phospholipidactually bilayer, the cell membrane also contains: proteins, sterols and sugars within the bilayer which help it perform specific functions. This model of the membrane is called the fluid mosaic model.  in The Cell Membrane Function The cell membrane has several important functions: 1- It forms a physical barrier to protect the inside of the cell from outside environment. specific carrier 2- It controls the transport of substances into and out of the cell. This is possible because the membrane is mulecolus semi-permeable. or sellctivegalwall spsific not all of them  The Cell Membrane 3- It plays a role in cell-to-cell communication. like the alum intranet affair.nl thbeEEHanh wall 4- It is an attachment surface for cell walls, other cells and the intracellular cytoskeleton.  Organelles do the work of cells The basic set of organelles found in most animal cells. - Nucleus - Endoplasmic reticulum - Golgi apparatus - lysosomes - Mitochondria - Peroxisomes - Ribosomes Model Animal Cell  Cell organelles are of 2 types Membranous Organelles. Endoplasmic Non-Membranous reticulum. Organelles. Mitochondria. 1. Ribosomes no cell membrane. Golgi. 2. Cytoskeletal. Lysosomes. structures  Many cell organelles are connected through the endomembrane system Many of these organelles work together in: during the synthesis of protein all of the organelles -Synthesis like cytoblasm -Storage, and mitochinaria etc -Export molecules. cortiappratee ER molecules with export  The Nucleus: Information Structure Central The nucleus is the largest cellular organelle in animals. praschromsons chromatin tangled is 88M the The nucleus is composed of: ofDNAspread 1- Nuclear Membrane 9 28 2- Nucleoplasm 3- Nucleolus mediffs 4- Chromatin and Chromosomes Yaedision IT it line envelope  chromsom Structure The Nucleus 1-Nuclear Membrane pervelopes Pores It surrounds and protects the contents of the nucleus nuclear pores. phospholipid wig It consists of double layer of membrane and it contains Phys.pe layer opid Lamina 1145 this It contains nuclear pores which permit exchange between nucleoplasm & cytoplasm. 81 Amd or  chromatin is yh The Nucleus found inside or divied fa.ge Structure the Nuclear DNA membrane into con hses 2- Nucleoplasm stacy known asChrohomes The liquid within the nucleus. It is similar to the cytosol within the cytoplasm until cell defiestRNA ifeng.gg 3- Nucleolus Proteins is a "sub organelle" of the cell nucleus. Made up of a combination of rRNA and proteins. Site of ribosomes synthesis. Nucleolus The nucleolus loses its identity during cell division. will disapper during divison  The Nucleus true chromatinStructure The nucleus is composed of: can be expressed exssulapblefteigDN.fi 4- Chromatin and chromosomes Strands of DNA wrapped around proteins called histones create chromatin. There are two types of chromatin: 2- f mpased chosen Heterochum Het 1- Euchromatin, is the less compact DNA form, and eroc contains genes that are frequently expressed by hro GTxpress.TT the cell. mat in, is if the the patheston mor DNA is more e compated then com pact for m, and contains INA  that is The Nucleus infrequently Structure 895 one up Chromatin forms chromosomes when it condenses into easily visible strands during cell division  Chromosome Structure Structure Nuclesosomes – Core of DNA wrapped around 8 histone proteins p plus linker DNA 1i liner DNA b. Solenoid – coiling of nucleosomes0871s baem 7 like phone cord in them c. Chromatin fiber – series of nucleosomes very strong stracture is important forthe d. Metaphase chromosomes function of  chromatin i.itin i.iiimi 8 iii fiii Iiii iii in.e DNA t aE.me Warraped iiiiiEi 2 f see iiiii protiens chromosome BE 5s fare at made the Prosses µ 1 of era scraptionf Regulgates iiiiiiii sina.io i 8 Hmscript afraid cnet.LI it doyt Heterochromatin methyaltion w ̅ loosens DNA I Enchromation  DNA Each human cell contains 46 chromosomes (except sperm or egg cells) i 29.19 oneextra 2 Gramm  Anucleated and polynucleated cells red blood cell Do not have a nucleus 1-1Anucleated cells contain no nucleus and are therefore incapable of dividing to produce daughter cells. I www SI 2- Polynucleated cells contain multiple nuclei.with a sing m.name In humans, skeletal muscle cells, called myocytes, become polynucleated during development It during development skeletal muscle cells fuse Gogther Multinucleated cells can also be abnormal in humans. leading Cells arising from the fusion of monocytes and macrophages, known as giant multinucleated cells, sometimes accompany that inflammation and are also implicated in tumor formation. a multi  thesetumors are generally benign I butcanbelocallyaggressive Giant-cell tumoralike of the bone (GCTOB) is a relatively uncommon tumor of the bone. It is characterized by the www.sina.ffff presence of multinucleated giant cells (osteoclast-like f cells). Malignancy in giant-cell tumor is uncommon and occurs in about 2% of all cases. ii one on many nudues inside abnormal Multinucleated giant cells due to an infection.  Day 2 Biomedical importance Functions The nucleus of a eukaryotic cell stores DNA and directs the cell's activities. DNA mitosis si.wreplactj.gg Nucleus contains the biochemical processes involved in the Replication t of DNA before mitosis. Its its Involved in the DNA repair. fi condition The nucleus repair damaged DNA this isimportantforpreventing mutations Transcription of DNA – RNA synthesis. could leadto dise such cancer chromatin DNA intoRNA to MRNA specifically mRNA messenger  g all cells has the same total of number gens but they differ The nucleus contains a variety of proteins: The process by which RNA is I 2min synthesized from 1- Enzymes mediate transcription. 2 a DNAtemplate RNA polymerases that synthesize the growing RNA molecule. ingint rip Topoisomerases that change the amount of supercoiling in DNA. É 4 help to relive thistension making it easier for to proceed 81 trgnmg.gr gtion 2- Enzymes involved in regulating the transcription. Transcription factors that regulate expression. GThisprote.in play a crucial role inregulating transcription they bindtospecificDIAsequeriesand  a yes Nuclear transport Small molecules can enter the nucleus without regulationand energy ATP needs energy is_ Macromolecules: RNA and Proteins are actively transported across the nuclear membrane with regulation by the nuclear pore complexes it Passive not allaw transport she 00 energy no need Of active for transport needs  M a Assembly and disassembly of the nucleus it's dispeers During its lifetime a nucleus may be broken down: o The process of cell division. o As a consequence of apoptosis e death  ny of a death in which series moleculars of Disorders of nucleus a cell leadto steps in itsdeath Defective nucleoli (singular = nucleolus) have been implicated in several rare hereditary diseases, mostly I neurodegenerative disorders such as Alzheimer’s and Huntington’s disease. ka eea.se bemsewehaieeencyTtE Parkinson’s disease may be caused by oxidative stress within cells due to defective nucleoli. the gene will expression aginist the reposions be a ffacted Antibodies to certain types of chromatin organization, particularly nucleosomes, have been associated with a number of autoimmune diseases, such as systemic lupus erythematosus, and multiple sclerosis These are known as anti-nuclear antibodies (ANA). yous more compacted less affctive Nucleus Summary  Cytoplasm: If it helps in the transportation of materials It is jelly-like substance containing water and miniral salts.the locationwhere have activities we manycellular Acts as a medium where biochemical reactions and most living processes occur within the cell. involved in Glycolysis Enzymes (glycolytic pathway) Glycolysis which the is proiessofbreakingfonnglucoset All the machinery for protein synthesis (mRNA,18tr mffyf.gg jffffftie transfer RNA, enzymes, and other factors) hey are Oxygen, CO2, electrolytic ions, low molecular weight substrates, metabolites, waste products, etc almost cytoplasm er Ess Contains organelles with different cell functions. roteins ribosome the  ffa so The Endoplasmic Reticulum: nefnugteteniyg one're is msn.ms Biosynthetic Factory Rugh no vibosoms they.is ribosomg Endoplasmic reticulum (ER) is a network of membranes throughout the cytoplasm of the cell. There are two kinds of endoplasmic reticulum: Smooth and rough. Stiff's.it Rough ER is embeddedrotien with ribosomes on cytoplasmic side. Smooth ER Rough ER membrane Is lacks attached ribosomes continuous with the nuclear envelope surrounding the nucleus Although physically interconnected, smooth and rough ER differ in structure and function. Biomedical importance Smooth Endoplasmic Reticulum IS UH many metabolic processes (synthesis & hydrolysis) Production fats soerspids 1- Lipids biosynthesis: synthesizes lipids, phospholipids as in plasma membranes, and steroids 2- Detoxification: the detoxification of alcohol, and other potentially harmful substances. like drugs storage 3- Sequestration ff of Ca++: Some smooth ER helps store and release calcium ions. wheneverthe cells needs the IS it win i plays a'critical role in syntesizingproteinsby cation ribosomes Rough ER The ER system i involved in synthesizingand serves Siq as a location for the proteins- synthesizing ribosomes. Directs molecules towards single places. o Intracellular storage (eg, in lysosomes and specific granules of leukocytes), www.i s inswitinteYaW o Provisional intracellular storage of proteins before exocytosis o Integral membrane proteins. msn.in Sends proteins to the Golgi apparatus. Synthesis of other organelles (lysosomes & Peroxisomes).  reactions e using molecular oxygen no a 18 α s Eg i Be jiii  e signal sequences direct proteins tointhe correct i organelle. 5 roti's destined No signal Proteins that from the ER iffee are supposed here a specific g fÉ ii ii mama i 0 proteins destined for the ER possess an N-terminal signal sequence that directs them to that organelle, whereas those destined to remain in the cytosol lack this sequence. Hansomedanggatt he level ofgens recombinant DNA techniques can be used to change the location of the two proteins  is involved in a Golgi Apparatus: finishes, sorts, and ships cell products The Golgi apparatus finishes, sorts, and ships cell products. This means it processes dyif proteins and lipids, modifies them, sorts them 3 main structures can be observed under EM : into vesicles, and prepares them for their final destination, whether inside Flattened vesicles. ffff.at the cell or outside. secretory vesicles. orlipids to be secret hey Microvesicles. in intracelly of a s involved The main structural unit of Golgi apparatus is a flattened membrane vesicle described as GOLGI SACCULE. Each stack of saccules in Golgi of complex possess 1. Forming face(Cis–face) 2. Maturing face(Trans-face)  Biomedical importance iii iiiiiiiiiii.ie Serves as a molecular warehouse and finishing if w ̅ factory for products manufactured by the ER. Protters's lipids it modifie and prepare - Products travel in transport vesicles from the ER to the Golgi apparatus. Ci's - One side of the Golgi apparatus functions as a receiving dock for the product and the other as a shipping dock. o d Trans fare Biomedical importance protiens lipids Jo - Products are modified as they go from cir one side to the Golgi apparatus to the face other side Tras Face - Prepares for “shipment” in vesicles from Now trans face to other sites gÉes ftp.nfo heidEell cis 78 and hides trans to the trans as they face productsmodify the they carry vacuoles 894 5 35des aegrfadaf.ly for 1- Vesicles for transport (the secretion of proteins from the cells(hormones, plasma proteins, and digestive enzymes). 2- Vacuoles for storage. for later use 3- lysosomes for find out later golgi Apparatus is also  9 11 KNOWN 958 Laissong Dalton complex Baker's https://youtu.be/iA8hFSHS6Ho Body  to Shipping and sorting done by the Golgi complex is a very important step in protein synthesis. If the Golgi complex makes a mistake in shipping the proteins to the right address, certain functions in the cell may stop. Defects in various aspects of Golgi function leads to 1. Congenital glycosylation disorders. 2. Muscular dystrophy. 3. Diabetes. 4. Cancer. 5. Cystic fibrosis.  acts like a disposal system breakdown for some molucing w Lysosomes: Digestive Compartments ̅ synthysizes a lot ofProtiens securry scell Membrane-bound vesicles responsible for the 0 intracellular digestion of both intra and extracellular 7 substances. miiiiiii.itEgEfeii iig Enzymes & membrane of lysosomes are synthesized by rough ER & transferred to the Golgi apparatus for processing. f lysosomes The membrane serves to safely isolate these potent enzymes from the rest of the cell. ensuring they don't why damge other parts of the cell by digesting cellular components unitent onally  Biomedical importance The enzyme content varies in different tissues according to the requirement of tissues or the edimeng metabolic activity of the tissue. Lysosomal membrane is impermeable and specific I translocators are required. i the cell a.tn membrane Contain lytic enzymes (Low pH) soso.ca a Digestion of large molecules Recycling of cellular resources enzymes jj need low acid IE i Apoptosis Efeelldeathtoremog work The metabolites that result are transported either by vesicles or directly across the membrane.  Cellular digestion wwIINoÑhh_f Phagocytosis Lysosomes carry out intracellular digestion by Phagocytosis Theprocess by which cells en 7 If ff solid matter first thing after the antifiction Lysosomes help digest food particles engulfed by a 1. cell. sina.IM ms A food vacuole binds with a lysosome. 2. The enzymes in the lysosome digest the food. 3. The nutrients are then released into the cell. Cellular digestion Digestive enzymes Lysosom e Digestion e Food vacuole Plasma membran e  lysosomes Cellular digestion can't 5 9 Products of lysosomal digestion are released and reutilized. FIFE Indigestible material accumulates in the vesicles called residual bodies and their material is removed by exocytosis. IS Some residual bodies in non dividing cells contain a high amount of a pigmented substance called Lipofuscin. 0T Also called age pigment or wear –tear pigment.  Recycler Lysosomes also help remove or recycle damaged parts of a cell by autophagy.. If ftp.ghe The damaged organelle is first enclosed in a membrane vesicle. WSI so d. Then a lysosome Fuses with the vesicle, Dismantles its contents, and Breaks down the damaged organelle. s.is Ifois enhanced in secretory cells that have Autophagy accumulated excess secretory granules. IIHJ IWi Digested products from autophagosomes are reutilized in the cytoplasm. HER  lysosome fuses with Yes Lysosome Vesicle containing damaged mitochondrion Digestion membrandes.ge Breaks the am or dam go here ETH  kill ifh it self i Apoptosis = cell death and apoptosis - Critical role in programmed destruction of cells in multicellular organisms IS Auto-destruct mechanism “cell suicide” Some cells have to die in an organized fashion, especially During development ex: development of space between your fingers During embryonic development ex: if cell grows improperly this self- destruct mechanism is triggered to remove damaged cell cancer over-rides this to enable tumor growth  Disorders of Tay-Sachs disease Lysosomes Lysosomes play an important role in the metabolism of several substances in the human body, and consequently many diseases have been ascribed to deficiencies of lysosomal enzymes Individual lysosomal enzymes are missing or inactive and this lead to the accumulation of that particular substance. lysosomes gets enlarged and they interfere the normal function of the cell. Diseases called lysosomal storage will diseases which are usually fatal empudes the LINT Most important is Tay-Sachs disease agraded lipids build up in brain cells Eakins child dies before age 5. enzymeisrequired  if the d sease I.IT Endomembrane System: Relationships among the major organelles of the endomembrane system  Ribosomes: Protein Factories Ribosomes are the structures where proteins are made. They are produced in the nucleolus Composed of rRNA and ribosomal proteins known as a Ribonucleoprotein 4 what is it made of ribosomes f D Consists of a large subunit and a small subunit 1. In Prokaryotes: only free ribosomes; 70S ribosomes large: 50S subunit 1. Eukaryotes: free and bound Small: 30s subunit ribosomes; 80S ribosomes Large: 60S subunit. Small: 40S  Some ribosomes are free ribosomes; others are bound. 1- Free ribosomes: Suspended in the cytoplasm (singly or in groups called polyribosomes) Involved in making proteins that function within the cytoplasm cell. 2- Bound ribosomes: Attached On the endoplasmic reticulum associated with nuclear envelope Associated with proteins packed in certain organelles or exported from the cell.  o Ribosomes make proteins for use in the cell and export 08 8 88 Nucleus, Ribosomes, & ER Disorders of ribosomes Defects in the function of ribosomes may cause: 1.Anemia (5 infants in 1 million are affected) 2.Cartilage hair hypoplasia 3.Shwachman diamond syndrome.(1 child in every 100,000 is born with ribosomal disorder) 4.Dyskeratosis congenita (1 child in 1 million is affected)  Mitochondria: factories of energy Consists of flattened membranous sacs called cisternae. Every type of cell has a different amount of mitochondria. Figure 1-18 Essential Cell Biology (© Garland Science 2010)  The singular for mitochondria is mitochondrion. A mitochondrion is composed of: 1- Outer membrane (smooth) 2- Inner membrane (folded) 3- Matrix: (liquid within inner membrane) 4- Christae (folds of the inner membrane) 0oz 5- Intermembrane space (liquide between membranes) 6- Each one also has singular circular chromosomes as well as its own ribosomes which allow it to self replicate.  Biomedical importance The main function of mitochondria is to produce energy for the cell in a chemical process called cell respiration. 3 The process by which chemical is energy thereleased oxidationduring organic 7 molecules 381 win it Chemical formula for cellular respiration: C6H12O6 +O2 Co2 + H2o + ENERGY  Both the membranes have different appearance and biochemical functions: Outer membrane: Inner membrane: i It is permeable to most ions It surrounds the matrix. and molecules which can It contains components of move from the cytosol to electron transport system. intermembranous space. 56T It is impermeable to most ions including H, Na, ATP, GTP, CTP and to large Matrix: molecules. It is enclosed by the inner special carriers are present mitochondrial membrane. (ATP –ADP transport). Contains enzymes of citric acid cycle. Mitochondria plays a key role in aging (apoptosis) Mitochondria have a role in their own replication- they contain copies of circular DNA. ribosoms Mitochondrial DNA has information for some mitochondrial proteins and some RNAs. 2016899 This DNA is inherited maternally. Mitochondrial matrix contains some rRNA and some tRNA used in the translation of mRNA. mDNA encodes some enzymes, involved in oxidative phosphorylation Most mitochondrial proteins are derived from genes in nuclear DNA.  Disorders of mitochondria Mutation rate in mt DNA is 10 times more. herthe mtochatp system The mutations of mtDNA are more likely to cause muscular dysfunctions. The most mitochondrial deficiency diseases are characterized by muscular dysfunction. Because of their high-energy metabolism, skeletal muscle fibers are very sensitive to mitochondrial defects. These diseases typically begin with drooping of the upper eyelid and progress to difficulties in swallowing and limb weakness. Generally, in these diseases the mitochondria show morphological changes. Peroxisomes Called Peroxisomes 0 because of their ability to produce or utilize H2O2. They are small, oval or spherical in shape. They have a fine network of tubules in their matrix.  Peroxisomes mdepenfse.tk About 50 enzymes have been identified. Enzymes synthesized by free ribosomes in cytoplasm. will Itecell function of thecell The number of enzymes fluctuates according to the function of the cells. t et Peroxisomes are relatively large in hepatocytes and kidney cells but very small in intestine cells so called microperoxisomes Smooth ER is riessph Is sopen  Biomedical importance Some peroxisomes use oxygen to break fatty acids down into smaller molecules that are transported to mitochondria and used as fuel for cellular respiration. Peroxisomes in the liver detoxify alcohol and other harmful compounds by transferring hydrogen from the poisons to oxygen and produce H2O2. the The H2O2 formed by peroxisomes is itself toxic, but the organelle also contains an enzyme (catalase) that converts H2O2 to water. matter which is safe  Disorders of Alembert's Peroxisomes A large number of disorders arise from defective peroxisomal proteins, because this organelle is involved in several metabolic pathways. The most common peroxisomal disorder is X-chromosome- linked adrenoleukodystrophy, caused by a defective integral membrane protein that participates in transporting very long- chain fatty acids into the peroxisome for oxidation. Accumulation of these fatty acids in body fluids destroys the myelin sheaths in nerve tissue, causing severe neurologic symptoms. Deficiency in peroxisomal enzymes causes the fatal Zellweger syndrome, with severe muscular impairment, liver and kidney lesions, and disorganization of the central and peripheral nervous systems. Summary Peroxisome oxidation of toxic molecules ribosomes builds proteins