BIO 123 Chapter 8 Notes
BIO 123 Chapter 8 Notes BIOL 123
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This 8 page Class Notes was uploaded by Amber Logan on Wednesday October 28, 2015. The Class Notes belongs to BIOL 123 at University of New Mexico taught by Dr. Dorothy C. Scholl in Fall 2015. Since its upload, it has received 62 views. For similar materials see Biology for Health Related Sciences and Non-Majors in Biology at University of New Mexico.
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Date Created: 10/28/15
Chapter 8 Notes The Cell Cycle Mitosis and Cancer 0 The Cell Theory 0 All cells come from preexisting living cells 0 All cells have DNA as the molecule of heredity o All living things are composed of 1 cells 0 All cells have 0 A plasma membrane made up of a phospholipid bilayer o Ribosomes DNA 9 RNA 9 proteins 0 Enzymes facilitatecatalyze reactions 81 Prokaryotes Reproduce by Binary Fission 0 First cells on Earth have replicated since the beginning 0 Vertical gene transfer when a bacterial cell divides and DNA is transferred to offspring daughter cells 0 Binary fission to split in half asexual process where parent cell copies its DNA and divides producing 2 genetically identical daughter cells clones 0 Horizontal gene transfer when DNA is transferred from 1 cell to another without replication 0 Bacterial conjugation plasmid DNA is transferred to another bacterium via pilus 0 Transformation when bacteria cells uptake plasmidsother DNA material from the environment 0 Transduction occurs when a virus incorporates its genetic material into a host cell 0 Can occur across species ie virus prokaryote introducing its DNA into a eukaryotic cell Vertical gene transfer www5hutterstockcom 163605500 Image 1 o Prokaryotes divide rapidly o E coli takes 20 minutes to divide 0 Big factor of antibiotic resistance develops when there is an error mutation in DNA replication allowing the daughter cells to evolve and adapt to their environment 82 The Eukaryotic Cell Cycle An Overview 0 Only eukaryotes can form multicellular organisms mitochondria produce more ATP than prokaryotes can and we can reproduce asexually or sexually 0 As we develop from a singlecelled zygote our cells become differentiated they only express certain genes Result development of tissues organs and organ systems 0 Eukaryotic cell cycle interphase mitotic phase see Image 2 o lnterphase nondividing part of the cellcycle Cells are still metabolically active during this stage 0 Mitotic phase mitosis cytokinesis I Mitosis division of nuclear DNA Cytokinesis division of the cytoplasm and its content ie organelles o Occurs in somatic cells somo body Are diploid cells have 2 copies of 1 gene 1 from each parent Humans have 23 pairs 46 total of homologous chromosomes contain the same genes at the same locus location on both chromosomes see Image 3 23IrCI pair determines sex XX for females and XY for males S Replication n t e rph of DNA A Homologous Pair of Chromosomes G1 Gap 1 Aquot I 68quot 9m Gene for eye color gt GeneforenzymeA gt Gene for cytochrome 0 cell prepares t0 dwldel A duplicated A duplicated chromosome chromosome M WOSIS came from mother came from father Cells that cell dwisnon cease dwisuon Image 2 Image 3 83 lnterphase nondividing stage of the cell cycle is still metabolically active 0 cell spends most of its life here 0 3 substagesphases 0 G1 cell growth 0 S phase DNA replication 0 G2 final preparations 0 some cells enter into Go stage permanent nongrowingnondividing stage comes after G1 when we become adults 0 Le neurons cartilage cardiac muscle etc First Gap G1 0 cell carries out its normal metabolic functions 0 stage after mitosis daughter cells are half the size of the parent cell 9 cell grows cytoplasm size doubles size and number of organelles increases etc gt G1 checkpoint proteins called cyclins make sure cell is healthy enough to move onto next stage 0 If it is not healthydoes not need to divide anymore cell either goes through apoptosis or goes into G0 phase Sphase 0 DNA is replicated 0 think 8 for synthesis of DNA 0 Sister chromatids identical chromosomes Held together at centromere Locusallele location on a chromosome that codes for a certain trait gt Checkpoint cyclins and other regulatory proteins make sure DNA is replicated correctly Second Gap G2 0 Cell makes final preparations for division 0 Cell contents divides 0 Cell structures involved in division are synthesized ie centrioles form and begin to organize the mitotic spindle gt G2 checkpoint makes sure that cell is ready to begin mitosis 84 The Mitotic Phase NOTE Dr Scholl has posted a PPT on Learn with detailed slides covering all of the stages of Mitosis I highly recommend going through her slides and my notes 0 Mitotic phase mitosis division of DNA cytokinesis division of cytoplasm and its contents Mitosis Allows us to repairregenerate somatic body cells 0 Somatic cells vs Gametes body cells sex cells eggs and sperm are diploid have 2 copies of are haploid have 1 copy of each each gene 1 from each parent gene 0 2n 23 o n 23 23 homologous pairs code for are the result of the crossing over the same trait of chromosomes that occurs in meiosis 5 substages 1 Prophase Chromatin condenses into chromosomes 92 total as a result of DNA replication in S phase Mitotic spindle begins to forms Nuclear membrane begins breaking down 2 Prometaphase Mitotic spindle attaches to sister chromatids at the centromere Kinetochore mitotic spindle fibers centromere Nuclear membrane completely breaks down Centrosomes migrate to opposite ends of the cell 3 Metaphase Chromosomes line up along the equator metaphase plate of the cell 0 This movement is controlled by the centrosomes 4 Anaphase Kinetochore spindle fibers shorten 9 sister chromatids are pulled apart 5 Telophase Chromatids are pulled to opposite ends of the cell and begin turning into chromatin again Formation of nuclear membrane begins Centrosomes shrink and mitotic spindle breaks down Mitosis Maternal Paternal Intelphase Prophase Metaphase Anaphase Telophase Image 4 0 Factors that regulate mitosis 0 Presence or lack of essential nutrients 0 Growth factors chemicals that stimulatesuppress growth ie vitamin D cytokines chemical messengers secreted by cells etc o Densitydependent inhibition when you reach a certain number of cells mitosis stops 0 Anchorage dependence cells need a platform to adhere to NASA and microchambers development of cells that do not need to anchor to a surface to divide 9 mitosis of neurons 0 In the lab cell cultures 0 Primary cell lines come directly from the animalsource 0 Cells will only divide 45 times because every time DNA replicates the telomeres repeating segments of DNA located at the end of eukaryotic chromosomes that prevent sections of DNA from being lost during replication of chromosomes are lost Cancer cells divide immortally Cytokinesis 0 Division of cytoplasmic material 0 Cleavage furrow forms when plasma membrane pinches together forming a new membrane and splitting the parent cell into 2 daughter cells 0 Results in 2 genetically identical daughter cells Image 5 85 Apoptosis Programmed Cell Death 0 Apoptosis programmed cell death selfdestruct switch 0 Protects other cellsthe organism from harm 0 vs necrosis when a cell uncontrollably digests its components due to trauma such as injury poison or an infection is harmful to the organism 0 Why it s needed Gets rid of cells that are not needed 0 Le webbing cells between fingers when we are fetuses gets rid of dangerous cells 0 Le cell infected w a virus 0 Induced by stress or chemical signals 9 formation of caspases executioner proteins that break down cells from the inside 9 formation of blebs irregular bulges in the cell membrane 9 cell shrinks and breaks down into apoptotic bodies Cancer 86 Cancer the Price We Pay for Being a Multicellular Organism 0 Cancer abnormal growth of cells that can potentially spread to other parts of the body 0 Are immortal not subject to the same regulation of cell division interphase is basically nonexistent mutations in checkpoints and growth factors 0 Tumors can be benign or malignant Benign not spreading to other tissues of the body Malignant cancer cells have metastasized and spread from the original tumor site 0 Stages of cancer Stage 1 early cancer benign Stage 2 depends on of lymph nodes involved Stage 3 depends on of lymph nodes involved Stage 4 metastatic malignant usually terminal 0 Cancer cells have damaged sections of DNA and stop expressing certain genes that are normally turned onstart expressing certain genes that are normally turned off Telomerase enzyme that breaks down telomeres 9 allows cancer cells to replicate repeatedly wout loss of DNA 0 Are your own cells don t behave like normal cells Why it s hard to find a cure cure could attack your healthy cells 87 Environment or Genetics The Causes of Cancer 0 Remember cancer arises because of damage to specific regions of DNA 0 Genes that cause cancer Protooncogenes normal genes involved w cell growth and development that can become an oncogene when theyother genes that regulate their expression mutate Oncogene a gene that under certain circumstances can transform a cell into a tumor cell 0 Mutagens cause damage to DNA lnclude carcinogens substances that cause cancer 0 Le radiation asbestos cigarette smoke etc 0 9095 of all cancer is caused by the environment 510 is caused by genetics 9 our lifestyles are more important than our genes 88 Types of Cancers and Treatments Types of Cancer 0 Over 100 different types 0 Get their names from their origin eg lung cancer originates in the lungs 0 Can also be classified by the type of cell the cancer originated in o Carcinomas derived from epithelial cells which line our body surfaces ie skin tracts linings of body cavities etc o Leukemia derived from blood cells Blood cells are formed in your bone marrow by stem cells when a stem cell divides you get 1 stem cell and 1 specialized cell that can be any cell in the body in this case a blood cell 1 type is triggered by a sexually transmitted virus called HTLV l or II which breaks down tumor suppressors protooncogenesturns on tumor promoters oncogenes 0 Top killing cancers 1 Lung cancer 99 of cases are attributed to smoking 3IrCI hand smoking when fabrics absorb smoke molecules and are spread that way 2 Prostate cancer in males 3 Breast cancer in females 4 Colon and rectal cancers silent killers asymptomatic symptoms don t show up until Stage 34 5 Malignant melanoma 6 Leukemia childhood cases are usually curable while adult cases are more difficult to cure 7 Ovarian cancer in females silent killer symptoms mimic other problems Cancer Treatments 0 There is no single cure 0 Most common treatment chemotherapy drugs radiation beams of intense energy 0 Childhood leukemia can often be cured by bone marrow transplant Best marrow match is often a sibling s Connections What We Can Learn from Cancer 0 Because cancer cells are immortal we might be able to learn how to slow our aging process by studying them 0 By studying cell cycle and genetics of cancer we may be able to learn how to grow organ clones from our own cells Picture Credits Image 1 httpwwwshutterstockcompic163605500stockphotoverticalversushorizontaIgene transferinbacteriahtml Image 2 httpwwwscqubccatheceIIcycIeauniversaIcellulardivisionprogram Image 3 httpscvmrsdabbswikispacescomHomologousChromosomesandDifferent Versions of Genes Image 4 httpswww bio purdue eduB CBLabp 1 093 Image 5 httpiwscolinedubiopagefacultymcculloch1406outlineschapter2011chap1 1htm Image 6 Image 7
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