Chapter 2 IB Biology 2. 1 Cell Scheme 2. 1. 1 Outline the cell scheme (2). •All organisms are tight of one or over cells •Cells are the lowest aces of existence •All cells conclude from preexisting cells •TOK: cell scheme substitutes the ancient ideas of unbidden breed or abiogenesis in which heavy subject assembles itself into subsistence contrives •Exception: muscle cells- over than 1 kernel, very long; (fungal cells) hyphae roots- not a uncombined ace; protoctista- not specialized to uncombined duty; subcellular monstrositys approve organelles 2. 1. Discuss the exemplification for the cell scheme (3). •Robert Hooke principal described cells in 1665 time observing hinder delay a microscope he built. Coined the tidings “cell”
Antoine van Leeuwenhoek observed the 1st subsistence cells and referred to them as lewdcules. “microscope” •In 1838, botanist Mathias Schleiden orderly that fixs are made of rebellious unalike nature designated cells. Later, Theoder Schwann made a contemptible proposition encircling lewds. •The 2nd doctrine continues to procure-about assistance consequently we hold not been telling to confront any subsistence existence that is not made of at fineest one cell. Louis Pasteur in the 1860s done experiments to assistance the latest doctrine. Behind sterilizing chicken broth by outburst, Pasteur illusioned that subsistence organisms would not ‘spontaneously’ revert. “biogenesis” •Only behind inhospitableness to preexisting cells was existence telling to reinspecify itself in the chicken broth. •Eukaryotes- mitosis; prokaryotes- binary fission; thus all cells hold a contemptible ancestor- contriveer ancestral contrive 2. 1. 3
State that unicellular organisms heave out all the dutys of existence (1). •Functions include: Metabolism- chemical reactions that answer delayin an organism •Growth- may be poor but is frequently obvious in some way •Reproduction- lineal molecules that can be ignoringed to offspaccentuation •Response- to environment is peremptorily to inception •Homeostasis- keep a faithful inner environment ex: temp •Nutrition- cater a spaccentuation of mixtures delay sundry chemical bonds which can be tedious to cater the organism delay the NRG and the nutrients compulsory to keep existence CHNOPS 2. 1. 4 Compare the not-absolute magnitudes of molecules, cell membrane density, viruses, bacteria, organelles and cells, using the mismisappropriate SI ace (3). Cells- 100 micrometers (plant) •Organelles- < 10 micrometers •Bacteria- 1 micrometer •Viruses- 100 nanometers
•Membranes- 10 nanometers dull •Molecules- 1 nanometer •Animal cell- 10 micrometers •cm = 10-2 m •mm = 10-3 m •um = 10-6 m •nm = 10-9 m •A = 10-10 m 2. 1. 5 Calculate the rectirectilinear magnification of drawings and the aimive magnitude of samples in pictures of notorious magnification (2). •Magnification = magnitude of picture disunited by the magnitude of sample •Magnification = measured diffusiveness / lamina bar roll •Actual magnitude = measured diffusiveness / magnification 2. 1. Explain the significance of the demeanor area to comignoaccentuation agreement as a rudiment limiting cell magnitude (3). •In the cell, the admonish of ebullition and devaspecify origination and admonish of respaccentuation decrease are dutys that halt of its compass. •Most of the chemical reactions answer in the delayin of the cell and its magnitude affects the admonish of these reactions.
•The demeanor of the cell, the membrane, restrains what representatives propose in and out of the cell. •Cells delay over demeanor are per ace comignoaccentuation are telling to propose representatives in and out of the cell, for each ace comignoaccentuation of the cell. As the width of the aim extensions, the demeanor area as-well extensions but at a plenteous sinferior admonish than the compass. •This media that a vast cell has hither demeanor area to procure in deficiencyed representatives and to rid the cell of devaspecify than a fine cell. •Besuit of this, cells are poor to the magnitude they can earn and calm?} be telling to heave out the dutys of existence. Vast lewds hold over cells not vastr ones. •A vast demeanor area to comignoaccentuation agreement media the cell can act over prolificly: for all ace of comignoaccentuation that requires nutrients or consequences devastate, there is over membrane to acceleration it. But this is not frequently an utility- cell can promote ebullition quickly.
•As organisms amplify, cells disunite. 2 fine cells are over prolific than one. •Alveoli in lungs maximize demeanor for gas fluctuate. 2. 1. 7 Specify that multicellular organisms illusion emergent properties (1). •Different monstrositys conclude conjointly to constitute arrangement •Cells-tissues-organs-etc. •Ability to propagate themselves. Allows possibility of amplifyth and for retrieval of injured or animationhither cells. 2. 1. 8 Explain that cells in multicellular organisms distinguish to heave out specialized dutys by expressing some of their genes but not others (3). Set-out out as uncombined cell that propagates at a speedy admonish then the consequenceing cells go thununidevise a incongruousiation (incongruous cells- incongruous dutys- to run an organism) arrangement to consequence all required cell profits that are compulsory for organism. •Every cell in a multicellular organism comprises all the genes of that organism. However, the genes that are activated differ from cell to cell. •Differentiation- when we rupture star multifarious into its ingredient pieces, they each answer to be pastre. Combined, they can percontrive a all new duty.
Cells delayin a multi cellular organism specialize their duty. •Examples: muscles cells, cardiac cells •This incongruousiation arrangement is the consequence of the face of undeniconducive inequitconducive genes but not others •Genes recognize for the origination of all incongruous cells in the organism •Each cell comprises all the genetic info for the origination of the adequate organism •Each cell beseems a inequitconducive profit of cell haltent of which DNA member beseems erratic 2. 1. 9 Specify that stock cells keep the magnitude to disunite and hold the power to distinguish along incongruous pathways (1). Keep power to disunite and distinguish into diversified cell profits •Embryonic stock cells keep the power to contrive any profit of cell in an organism and can equal contrive a adequate organism •When stock cells disunite to contrive a inequitconducive profit of web, they as-well consequence some cells that stop as stock cells. This recognizes for the endhither origination of a defolinferior profit of web.
•Pluripotent- bestow amalgamate to any profit of cell •Treating complaints? 2. 1. 10 Outline one sanitary use of stock cells (2). •Reassign distinguishd cells obsolete due to deterioration Sanitary cloning- implanted stock cells substitute obsolete cells •Tissue- inequitconducive stock cells- these cells live in undeniconducive web profits and can merely consequence new cells of that defolinferior web •For copy, stock cells hold been introduced to humans to substitute the injured blight cream of some leukemia endurings •Bone cream conveys are one of the sundry sanitary uses of stock cells. Stock cells establish in the blight cream bestow amalgamate to the red lineage cells, pure lineage cells and concoctionlets in the association. These stock cells can be used in blight cream conveys to handle mass who hold undeniconducive profits of cancer.
When a enduaccentuation has cancer and is bestown proud doses of chemotherapy, the chemotherapy kills the cancer cells but as-well the usual cells in the blight cream. This media that the enduaccentuation cannot consequence lineage cells. So antecedently the enduaccentuation is handleed delay chemotherapy, he or she can rafter a blight cream product in which stock cells are removed from the blight cream by using a deficiencyle which is inserted into the pelvis (hip blight). Alternatively, if stock cells cannot be used from the enduaccentuation then they can be producted from a matching donor.
After the chemotherapy handlement the enduaccentuation conquer hold a blight cream transfix in which the stock cells are conveyed folinferior into the enduaccentuation thununidevise a drop, usually via a specify in the chest or the arm. These conveyed stock cells conquer then confront their way folinferior to the blight cream and set-out to consequence wellsome lineage cells in the enduring. For-this-conclude the sanitary use of stock cells in blight cream conveys is very deep as it recognizes some endurings delay cancer to rafter proud chemotherapy handlement.
Without this sanitary use of stock cells, endurings would merely be telling to engage low doses of chemotherapy which could inferior their chances of cuaccentuation the complaint. •Ethical issues- corenic stock cells conclude from cores obtained from labs doing IVF. compromises egress of core. 2. 2 Prokaryotic Cells 2. 2. 1 Draw and dedicate a diagram of the ultrabuilding of Escherichia coli (E. coli) as an copy of a prokaryote (1). •Plasmid is round monstrosity not on diagram. Refer to dimensions. •Size of cell: 1-2 um •Absence of membrane skip organelles Prokaryote copys: (face at notes for pictures) •straight rod- Escherichia •Club patternd rod- corynebacterium •Spore contriveing rods- bacillus •Coccus Staphylococcus 2. 2. 2 Annotate the diagram delay the dutys of each designated building. •Cell rampart: Protects the cell from the delayout environment and keeps the pattern of the cell. It as-well prevents the cell from severance if inner influence amalgamates. ?? •Plasma membrane: Semi-permetelling membrane that restrains the bes affecting into and out of the cell. It comprises all and peripheral proteins.
Substances ignoaccentuation thununidevise by either erratic or ignoringive rapture.?? •Cytoplasm: Contains sundry enzymes used to catalyze chemical reactions of metabolism and it as-well comprises the DNA in a tract-of-land designated the nucleoid. Ribosomes are as-well establish in the cytoplasm. ?? •Pili: Acceleration bacteria amalgamate to each other for the fluctuate of genetic representative. Complicated in perform-over of DNA in a arrangement designated conjugation (trodden adjunction betwixt bacterial cells in which plasma DNA is perform-overred betwixt a donor and a berth cell) •Flagella (consummate flagellum): Made of a protein designated flagellin.
Helps bacteria propose environing (mobility) •Ribosomes: They are the birth of protein organization. Contributes to protein organization by translating herald RNA.?? unobstructed in cytoplasm (70s) •Nucleoid: Tract-of-land compriseing DNA; complicated delay cell restrain and reorigination •Plasmid- fine, round DNA not alike to deep chromosome; invert rebelliously of chromosomal DNA; not required by cell below usual stipulations but it may acceleration the cell mixture to strange circumstances; usual to confront at fineest one anti-biotic hindrance gene delayin a plasmid •Slime capsule- sticky layer delayout of cell rampart, sticks cells conjointly . 2. 3 Identify buildings from 2. 2. 1 in electron micrographs of liver cells (2). 2. 2. 4 Specify that prokaryotic cells disunite by binary fission (1). •Binary fission- pastre disruption arrangement in which DNA is copied and 2 daughter chromosomes beconclude designated to incongruous tract-of-lands on plasma membrane and cell disunites into 2 genetically particular daughter cells. Arrangement product of cell 2. 3 Eukaryotic Cells 2. 3.
1 Draw and dedicate a diagram of the ultrabuilding of a liver cell as an copy of an lewd cell (1). . 3. 2 Annotate the diagram delay the dutys of each designated building. •Ribosomes: Establish either unmoulded unobstructed in the cytoplasm or designated to the demeanor of the ununidevise endoplasmic reticulum and in mitochondria and chloroplast. Ribosomes are the birth of protein organization as they render herald RNA to consequence proteins. •Rough endoplasmic reticulum: Can deviate proteins to fluctuate their duty and/or purpose. Synthesizes proteins to be excreted from the cell. Lysosome: catalyze the rupturedown of proteins, nucleic aculeateds, lipids and carbs, amalgamate delay old or injured organelles so recycling can answer, rupturedown of representatives that are brought in by phagocytosis •Golgi attendance: Receives proteins from the ununidevise endoplasmic reticulum and may exalt deviate them. It as-well packages proteins antecedently the protein is sent to it’s ultimate purpose which may be intracellular or extracellular. •Mitochondrion: Is lawful for aerobic respiration. Converts chemical distillation into ATP using oxygen. •Nucleus: Contains the chromosomes and for-this-conclude the lineal representative.
It is lawful for restrainling the cell. Extra: •Smooth ER- origination of membrane phospholipids can cellular lipids, origination of sex hormones, detoxification of drugs in liver, storage of calcium ions deficiencyed for muscle contractions, raptureation of lipid based mixture, to aid in liver in releasing glucose into lineagestream when deficiencyed •Centrosome- a couple of centrioles at upupright angles; complicated in assembling microtubules which are deep in providing building and recognizeing proposement and cell disruption •Vacuole- storage organelle; accumulation germinative patronage to cater alimentation, metabolic devastates and toxins to be expelled, and ater; enables cells to hold a prouder demeanor area to comignoaccentuation agreements equal at vastr magnitudes; in fixs, upengage of h2o caters inflexibility 2. 3. 3 Identify buildings from 2. 3. 1 in electron micrographs of liver cells (2). 2. 3. 4 Compare prokaryotic and eukaryotic cells (3). Prokaryote Eukaryote DNA in a accentuation contrive delayout proteinDNA delay proteins as chromosomes/chromatin DNA unobstructed in the cytoplasm- no kernelDNA enclosed delayin a nuclear compress No mitochondriamitochondria 70S ribosomes80S ribosomes
No inner compartmentalization to contrive organellesinner compartmentalization offer to contrive sundry profits of organelles Magnitude hither than 10 micrometersSize over than 10 micrometers •also: unicellular vs. multicellular •no membrane skip organelles vs. membrane skip organelles •binary fission vs. mitosis •asexual reorigination vs. asexual and sexual reorigination •similarities: twain cells hold some character of delayout skipary that frequently compromises a plasma membrane, twain heave out all dutys of existence, DNA is offer in twain . 3. 5 Specify 3 differences betwixt fix and lewd cells (1). Fix Lewd Outer cell rampart delay a plasma membrane honorable delayinOnly a plasma membrane Chloroplasts No chloroplasts Vast centrally located vacuolesNo vacuoles/ or fine ones Accumulation carbs as starchStore carbs as glycogen Do not comprise centrioles delayin a centrosome areaContain centrioles delayin a centrosome area Fixed, repeatedly bowed, pattern consequently of a unpliant cell rampartCell is pliant and over approvely to be a rounded pattern . 3. 6 Outline 2 roles of extracellular ingredients (3).
•The fix cell rampart bestows the cell a lot of power and prevents it from severance below proud influence as it is made up of cellupromote crystallized in groups designated microfibrils. It bestows the cell its pattern, prevents immoderate inspire up engage by osmosis and is the conclude why the all fix can restrain itself up abutting dismally. Prevents startning of pathogens. Allows turgor influence/ proud influence to enucleate delayin the cell. The lewd cell comprises glycoproteins in their extracellular matrix (ECM) which are complicated in the assistance, proposement and adhesion of the cell. Cell to cell interaction, powerens plasma membrane, recognizes bindment betwixt neighboring cells, troddens stock cells to distinguish 2. 4. 1 Draw and dedicate a diagram to illusion the building of membranes (1). 2. 4. 2 Explain how the hydrophilic and hydrophobic properties of phospholipids acceleration to keep the building of cell membranes (3). One area of membrane is inspire discerptible and polar and is hydrophilic •The other area isn’t inspire discerptible and is non polar- hydrophobic
•These hydrophobic and hydrophilic tract-of-lands suit phospholipids to frequently align as a bilayer if there is inspire offer and there is a vast enumerate of phospholipid molecules •Membrane is pliant past fatty aculeated folinferior do not strongly invite one another •What keeps the overall building of membrane is the leaning inspire has to contrive hydrogen bonds •In hydrophobic tract-of-land (fatty aculeated followers) in lewd cells these are cholesterol molecules- designate membrane flowingity (changes temp) •Proteins are embedded in flowing matrix of phospholipid bilayer (mosaic pi) •Integral proteins hold twain hydrophobic and hydrophilic tract-of-lands in the concordant protein •Hydrophobic tract-of-land (mid individuality of phospholipid membrane) restrains protein in assign •Hydrophilic tract-of-land is laagered to inspire explanations on either margin of membrane •Peripheral proteins do not abut into the average hydrophobic tract-of-land but stop skip to the demeanor of the membrane 2.
4. 3 List the dutys of membrane proteins (1). •Hormone styptic births- hold inequitconducive patterns that fit pattern of inequitconducive hormone •Enzymatic action- catalyze chemical reactions •Cell adhesion- proteins hold conjointly to contrive connections •Cell to cell communication- cater identification •Channels for ignoringive rapture- proud to low attention •Pumps for erratic rapture- proteins shuttle a be from one margin of membrane to another by changing pattern; ATP 2. 4. 4 Define osmosis and clearance (1). •Diffusion is the ignoringive proposement of particles from a tract-of-land of proud attention to a tract-of-land of low attention.
Osmosis is the ignoringive proposement of inspire molecules, despite a imperfectly permetelling membrane, from a tract-of-land of inferior solute attention to a tract-of-land of prouder solute attention (hypo-osmotic explanation to hyperosmotic explanation). •Facilitated clearance- compromises a membrane delay inequitconducive consigner proteins that are captelling of combining delay the be to and its proposement 2. 4. 5 Explain ignoringive rapture despite membranes by pastre clearance and facilitated clearance (3). •Simple clearance- bes other than inspire propose betwixt phospholipids molecules or thununidevise proteins which hold channels •Facilitated clearance- nonchannel protein consigners fluctuate pattern to recognize proposement of bes other than inspire. No NRG.
Polar molecules deficiency acceleration. •Substances that propose ignoringively despite membrane are influenced by magnitude and pattern •Small bes and nonpolar propose delay ease; vast, polar, or twain do not •Channel proteins- beget a hydrophilic pore in membrane thununidevise which fine fluctuated particles (ions) can difamalgamate into cell •Transport proteins- acceleration propose bes (glucose) into cell. Substadmonish binds to protein which carries molecules despite membrane and releases it delayin cell 2. 4. 6 Explain the role of protein cross-examines and ATP in erratic rapture despite membranes (3). •Active rapture compromises the proposement of bes thununidevise the membrane using NRG from ATP.
The utility of erratic rapture is that bes can be proposed abutting the gradient, signification from low to proud attention •This is practicable consequently the cell membrane has protein cross-examines embedded it which are used in erratic rapture to propose bes using ATP •Each protein cross-examine merely raptures undeniconducive bes so the cell can restrain what concludes in and goes out •Transport or consigner proteins •Ex: Na +/ K + cross-examine. Sodium proposed out of cell, potassium proposed in (deep for strength cells) 2. 4. 7 Explain how vesicles are used to rapture representatives delayin a cell betwixt the ununidevise ER, Golgi attendance, and plasma membrane (3). •Materials are infections betwixt ununidevise ER, Golgi app, and plasma membrane •Nucleus comprises chromosomes that comprise genes for coding proteins.
RNA ignoringes from kernel to cytoplasm •Rough ER comprises ribosomes which constitute proteins calculated for ship-yield •Protein goes into lumen of Golgi app for arrangementing antecedently it leaves thununidevise the cell demeanor membrane by exocytosis 2. 4. 8 Describe how the flowingity of the membrane recognizes it to fluctuate pattern, rupture and recontrive duaccentuation endocytosis and exocytosis (2). •The phospholipids in the cell membrane are not valid but are in a flowing specify recognizeing the membrane to fluctuate its pattern and as-well vesicles to amalgamate delay it. •This media bes can invade the cell via endocytosis and egress the cell via exocytosis. The membrane then receipts to its contriveer specify. •In exocytosis the vesicles amalgamate delay the membrane expelling their gratified delayout the cell.
The membrane then goes folinferior to its contriveer specify. Endocytosis is a contemptible arrangement which compromises the draging of the plasma membrane interior so that a vesicle is straightened off it and then this vesicle can heave its gratified anywhere in the cell. •Cell engages up be by outside it delay membrane, ATP •2 profits: •pinocytosis (be is fluent) •phagocytosis (be is valid) •endocytosis and exocytosis- erratic rapture that requires ATP; contemptible in unicellular organisms Summary of arrangementes: ATP requiredConcentration gradient Diffusion
NoDown (proud to low) Facilitated clearanceNoDown OsmosisNoDown Erratic rapture delay consigner proteinsYesAgainst is practicable EndocytosisYesAgainst is practicable 2. 5 Cell Disruption 2. 5. Outline the quantitys in the cell cycle, including interbearing (G1, S, G2), mitosis, and cytokinesis (2). •The principal quantity of cell disruption is interbearing which is disunited into 3 bearings; G1, S and G2. The cell cycle set-outs delay G1 (Gap bearing 1) duaccentuation which the cell amplifys vastr. This is followed by bearing S (synthesis) duaccentuation which the DNA is invertd. Finally, G2 (gap bearing 2) is the promote amplifyth bearing in which organelles extension in enumerate, cell amplifys and preps for mitosis, DNA starts to clip contrive chromatin to chromosomes and microtubules start to contrive. •? The fourth quantity is mitosis, which is disunited into prophase, metaphase, anabearing and telophase.
Duaccentuation mitosis the spindle fibers bind to the chromosomes and drag sister chromatids privately, providing the concordant genetic representative to each of these locations. This quantity unconnecteds the two daughter genomes. •Finally, cytokinesis is the latest quantity duaccentuation which the cytoplasm disunites to beget two daughter cells. In lewd cells the cell is straightened in two to contrive a cleavage furrow time fix cells contrive a concoction betwixt the dividing cells. 2. 5. 2 Specify that tooths (cancer) are the consequence of stormy cell disruption and that these can answer in any organ or web (1). •Proto-oncogenes are genes that consequence proteins, which inflame amplifyth (cell disruption). If derangement answers, a tooth conquer contrive. Mutations: radiation, viruses, chemicals that are carcinogenic, EM radiation 2. 5.
3 States that interbearing is an erratic duration in the existence of a cell when sundry metabolic reactions answer, including protein organization, DNA answer, and an extension in the # of mitochondria and/or chloroplasts (1). 2. 5. 4 Describe the equalts that answer in the 4 bearings of mitosis (2). •Duaccentuation prophase, chromatin beseems chromosomes, nuclear compress disintegrates, the spindle microtubules start to contrive, centrosomes propose inland oppobirth poles of cell due to diffusivenessening microtubules. Each chromosome consists of 2 particular sister chromatids held conjointly by a centromere. Duaccentuation metaphase, the chromatids propose to the equator and the spindle microtubules from each pole bind to each centromere on oppobirth margins. •Duaccentuation anaphase, the spindle microtubules drag the sister chromatids privately splitting the centromeres. This splits the sister chromatids into chromosomes. Each particular chromosome is draged to oppobirth poles. Chromatids of each duplicated chromosome unalike and beconclude unduplicated chromosome
•Duaccentuation telophase, the spindle microtubules rupture down and the chromosomes uncoil and so are no longer individually perceptible. As-well the nuclear membrane reconstitutes. Chromosomes beconclude chromatin (shapeless). Centrioles invert in lewd cells. The cell then disunites by cytokinesis to contrive two daughter cells delay particular genetic nuclei. 2. 5. Explain how mitosis consequences 2 particular nuclei (3). •Duaccentuation prophase, the chromosomes beconclude perceptible. The nuclear compress disintegrates and the spindle microtubules amplify and avail from each pole to the equator. •At metabearing the chromatids propose to the equator. The sister chromatids are two DNA molecules contriveed by DNA answer and are for-this-conclude particular.
•These sister chromatids are then unconnectedd in anabearing as the spindle microtubules bindes to centromere and drags the sister chromatids to oppobirth poles. As the sister chromatids unalike they are designated chromosomes. This media that each pole has the concordant chromosomes (concordant genetic representative). Finally the microtubules rupture down, the chromosomes uncoil and the nuclear membrane reconstitutes. The cell then disunites into two daughter cells delay genetically particular nuclei. •4 chromosomes in originator cell = 4 chromosomes in each daughter cell •duplicated chromosome delay 2 seaboards alike by centromere and chromosome is 1 seaboard 2. 5. 6 Specify that amplifyth, corenic enucleatement, web relit, and asexual reorigination compromise mitosis (1). •Growth- origination of contemptible cells •Embryonic enucleatement- recognizes zygote to amplify into multicellular organism •Tissue relit- wounds deficiency particular retrieval cells •Asexual reiter-ation- recognizes for a speedy and expressive extension in enumerate of individuals