OCR BIOL 2036SEF/S236F Cellular and Molecular Biology Revision Note PDF

BIOL 2036SEF/S236F Cellular and Molecular Biology Revision Note Topic 1 – Topic 4(Part 1) Topic 1 Principle of Cell Signalling (Part I) BIOL 2036SEF / S236F Cellular and Molecular Biology Autocrine Types of Signalling Extracellular fluid ▪ What are the differences? Molecular Biology of the Cell 6th...

BIOL 2036SEF/S236F Cellular and Molecular Biology Revision Note Topic 1 – Topic 4(Part 1) Topic 1 Principle of Cell Signalling (Part I) BIOL 2036SEF / S236F Cellular and Molecular Biology Autocrine Types of Signalling Extracellular fluid ▪ What are the differences? Molecular Biology of the Cell 6th Edition Embryo development / Immune response Immune response Nerve impulse Growth / Metabolism 3 4 Types of Signalling Direct Contact Paracrine Endocrine Synaptic Distance Types of Tissues Duration of the Signal (molecules) Short /long Same Tissues Transient Muscle contraction Short Between different cells types Seconds Immune response Long Different tissues / organs Hours Hormones Long/ Between Synapse Between two nerve cells Milli-seconds Nerve impulse Examples 5 Cellular Response is the Result of Combination of Signals ▪ Cells receives multiple signals ▪ Cell respond by integrating all the signals Molecular Biology of the Cell 6th Edition 6 Receptors are Classified into Cell Surface Receptor and Intracellular Receptor ▪ Hydrophilic signalling molecules ▪ Hydrophobic, small signalling molecules Molecular Biology of the Cell 6th Edition 7 They play an important role in the transmission of neuronal signals at the synapses and the neuromuscular junctions There are Three Types of Cell-Surface Receptor ▪ Ion-channel-coupled receptor ▪ G-protein-coupled receptor ▪ Enzyme-coupled receptor Neurotransmitter binds  Ion channels opens  Ions moves through channel, across cell membrane Molecular Biology of the Cell 6th Edition 8 GPCRs are involved in a wide variety of physiological processes. Behavioral and mood regulation: Receptors in the brain bind several different neurotransmitters, including serotonin, histamine GABA and glutamate Autonomic nervous system transmission: Both the sympathetic and parasympathetic nervous systems are regulated by GPCR pathways, responsible for control of many automatic functions of the body such as blood pressure, heart rate, and digestive processes = catalytic receptor 9 Autophosphorylation Protein Kinase Docking The binding of an extracellular ligand causes enzymatic activity on the intracellular side Examples of the enzymatic activity include: Receptor tyrosine kinase, as in fibroblast growth factor receptor. Most enzyme-linked receptors are of this type. Serine/threonine-specific protein kinase, as in bone morphogenetic protein Guanylate cyclase, as in atrial natriuretic factor receptor Molecular Biology of the Cell 6th Edition 10 11 Typical G-Protein-Coupled Receptor Signalling Pathway via cAMP Molecular Biology of the Cell 6th Edition 12 Typical G-Protein-Coupled Receptor Signalling Pathway via cAMP Molecular Biology of the Cell 6th Edition ▪ Binding of Glucagon → GTP-bound G-protein subunit → active Adenylate Cyclase (AC) ▪ AC → synthsize cyclic AMP (cAMP) or degrade by phosphodiesterase (PDE) *control by PKC ▪ cAMP → activate PKA & cAMP-response-elementbinding protein (CREM) → transcriptional program of gluconeogenesis 13 Cyclic-AMP ▪ A secondary messenger ▪ Reply rapid response (minutes) ▪ Rapid cycling between ATP and 5’AMP ▪ Trigger Ca2+ release ▪ Signal mediated by PKA 14 Typical G-Protein-Coupled Receptor Signalling Pathway via phospholipid Molecular Biology of the Cell 6th Edition 15 ▪ What is ▪ Phosphatidylinositol signal pathway? Extracellular signal molecule binds with the G-protein receptor (Gq) activates phospholipase C (PLC) located on the plasma membrane. PLC hydrolyses phosphatidylinositol 4,5 biphosphate (PIP2) → two second messengers: inositol 1,4,5-triphosphate(IP3) diacylglycerol (DAG) ▪ IP3 (water soluble molecule) binds with the IP3 receptor in the membrane of the smooth endoplasmic reticulum and mitochondria → open Ca2+ channels. ▪ DAG helps activate protein kinase C (PKC) → phosphorylates many other proteins → changing catalytic activities → cellular responses. 16 Phosphatidylinositol 4,5bisphosphate ▪ Phospholipid on plasma membrane ▪ PIP2 catalysed by phospholipase-C ▪ IP3 diffuse through cytosol ▪ Diacylglycerol on plasma membrane Molecular Biology of the Cell 6th Edition q 17 G-Protein-Coupled Receptor Signalling Pathway via PIP2 Molecular Biology of the Cell 6th Edition 18 ▪ G-protein q activates phospholipase C (PLC) ▪ Activated PLC cleaves PIP2 into inositol 1,4,5-triphosphate (IP3) and diaglycerol (DAG) ▪ IP3 diffuse in the cytoplasm and binds to IP3 receptor on the ER surface ▪ The binding open channel and calcium ions diffuse from ER to the cytoplasm ▪ Ca2+ pumps on the surface of plasma membrane and or by coupled transport of sodium ions from the outside (10-7M  10-6M) ▪ Increase in cytosol [Ca2+] open ryanodine receptor on ER surface  further increase cytosol [Ca2+] ▪ High cytosol [Ca2+] inhibit IP3 receptor and ryanodine receptor at a delayed time  delayed negative feedback ▪ High cytosol [Ca2+] causes translocation of protein kinase C (PKC) from cytosol to plasma membrane ▪ Diaglycerol remains in plasma membrane and binds with PKC ▪ Diaglycerol, Ca2+, and phosphatidylserine activates PKC ▪ Activated PKC phosphorylate effector proteins 19 G-Protein-Coupled Receptor Signalling Pathway via PIP2 ▪ G-protein Gaq activated and activate phospholipase C, which catalyzes the formation of two intracellular messengers, IP3 and DAG, from PIP2 (phosphatidylinositol 4,5-bisphosphonate). Molecular Biology of the Cell 6th Edition 20 ▪ Ligand binding results in receptor dimerization ▪ Mutual phosphorylation of tyrosine residues in the General Process of ECR – RTK Pathway active site of the tyrosine kinase domain of the dimerised receptors ▪ Phosphorylation of tyrosine residues results in conformational change and fully activate the tyrosine kinase domain by generating phosphorylated tyrosine docking sites Molecular Biology of the Cell 6th Edition 21 Intracellular Signalling Proteins of ECR – Receptor tyrosine kinases (RTK) Pathway The signal is terminated by a phosphatase that removes the phosphates from the phosphotyrosine residues. Topic 2 Anabolism of Biomolecules BIOL 2036SEF/S236F Cellular and Molecular Biology Glucose Metabolism 24 What is Glucose Metabolism ? ▪ There are 4 main processes that involved in glucose metabolism : i) Gluconeogenesis ii) Glycogenolysis iii) Glycolysis iv) Glycogenesis 25 Protein Metabolism 27 Amino Acid Metabolism 28 29 Amino acids degradation ▪ The general ways of amino acids degradation ▪ 1. Deamination - Elimination of amino group from amino acid with ammonia formation. - Types of deamination : i) Oxidative ii) Reductive iii)Hydrolytic iv)Intramolecular 2. Transamination 3. Decarboxylation 30 Deamination ▪ - Elimination of amino group from amino acid with ammonia formation. ▪ - Types of deamination : i) Oxidative ii) Reductive iii) Hydrolytic iv) Intramolecular 31 Oxidative Deamination ▪ L-Glutamate dehydrogenase present in both cytosol and mitochondria to the liver. ​L-Glutamate takes part in amino acids deamination. ▪ Removes the amino groups as an ammonium ion from glutamate ▪ Provides alpha-ketoglutarate for transamination. 32 33 Transamination ▪ Transfers an amino group to a ketoacid to form new amino acids. ▪ responsible for the deamination of most amino acids ▪ This is one of the major degradation pathways which convert essential amino acids to non-essential amino acids ▪ The enzyme that involved is aminotransferase (transaminase) ▪ There are different reaction of transaminases between alanine aminotransferase and aspartate aminotransferase. 34 Glutamate's amino group, in turn, is transferred to oxaloacetate in a second transamination reaction yielding aspartate. Glutamate + oxaloacetate ↔ α-ketoglutarate + aspartate 35 36 Transamination pathway 37 Decarboxylation ▪ The process to remove of carbon dioxide from the amino acid with formation of amines. ▪ The enzyme that involved is decarboxylases. The coenzyme is pyrpdoxalphosphate Lipids Metabolism 39 Comparison of b-oxidation and fatty acid synthesis ▪ Conversion of purines, their ribonucleosides, Biosynthesis of purine nucleotides and their deoxyribonucleosides to mononucleotides involves so called “salvage reaction. ▶ Liver is the major site for purine nucleotide synthesis. ▶ Erythrocytes, polymorphonuclear leukocytes and brain cannot produce purines. ▶ Folic acid is essential for the synthesis of purine nucleotides. Folic (methotrexate) are employed to control cancer. 40 41 Biosynthesis Of Pyrimidine Nucleotides ▪ ▶ The catalyst for the initial reaction is cytosolic carbamoyl phosphate synthase II, *DO NOT mix up with mitochondrial carbamoyl phosphate synthase I, it is for urea synthesis. ▪ ▶ Phosphoribosyl pyrophosphate (PRPP), an early participant in purine nucleotide synthesis, is a much later participant in pyrimidine biosynthesis. ▪ ▶ Phosphoribosyl pyrophosphate (PRPP) acts as a cofactor for uridine monophosphate synthetase (UMPS) which converts orotic acid into UMP (precursor). ▪ ▶ Mammalian cells reutilize few free pyrimidines, “salvage reactions” convert the ribonucleosides (uridine and cytidine) and the deoxyribonucleosides (deoxythymidine and deoxycytidine) to their respective nucleotides. 42 Biosynthesis Of Pyrimidine Nucleotides ▪ ▶ The catalyst for the initial reaction is cytosolic carbamoyl phosphate synthase II, *DO NOT mix up with mitochondrial carbamoyl phosphate synthase I, it is for urea synthesis. ▪ ▶ Phosphoribosyl pyrophosphate (PRPP), an early participant in purine nucleotide synthesis, is a much later participant in pyrimidine biosynthesis. ▪ ▶ Phosphoribosyl pyrophosphate (PRPP) acts as a cofactor for uridine monophosphate synthetase (UMPS) which converts orotic acid into UMP (precursor). ▪ ▶ Mammalian cells reutilize few free pyrimidines, “salvage reactions” convert the ribonucleosides (uridine and cytidine) and the deoxyribonucleosides (deoxythymidine and deoxycytidine) to their respective nucleotides. 43 44 1. FOLATE BIOCHEMISTRY ▪ ▪ Tetrahydrofolate is synthesized by two mechanisms: ▫ Conversion of folate to dihydrofolate and dihydrofolate to tetrahydrofolate is catalyzed by dihydrofolate reductase (DHFR). ▫ Methyltetrahydrofolate from liver stores is converted to tetrahydrofolate, a reaction that requires VITAMIN B12. Two steps in the conversion of 5phosphoribosylamine to IMP (purine synthesis) use tetrahydrofolate as a carbon donor. ▪ Tetrahydrofolate is also involved in the generation of dTMP from dUMP (pyrimidine synthesis) – this reaction is catalyzed by thymidylate synthase (see 2A below). 45 Topic 3 Cell Surface Molecules and Cellular Communication BIOL 2036SEF/S236F Cellular and Molecular Biology Extracellular Matrix Molecules and Integrins 48 ▪ Proteoglycan Water-hydrated gel ▪ Hyaluronan Components of Extracellular Matrix (ECM) ▪ Collagen – very strong fiber ▪ Elastin – fibrous protein ▪ Fibronectin – connect ECM to integrin Fibrous Structural Proteins ▪ Laminin ▪ Integrin Connect ECM to cells 49 Components of Extracellular Matrix (ECM) Provide framework for fibrous proteins; ▪ Proteoglycan ▪ Hyaluronan Compressive resistance Lubrication ▪ Collagen ▪ Elastin Tensile strength and recoil 50 ▪ ECM helps to fix the relative positions of different cells ▪ ECM is not static but dynamic ▪ ECM does not just provide structural function ▪ ECM also participate in cell-cell communication and gene regulation Deville, S. S., & Cordes, N. (2019). The Extracellular, Cellular, and Nuclear Stiffness, a Trinity in the Cancer Resistome—A Review. Frontiers in Oncology, 9. 51 Functions of ECM ▪ Mechanical Support ▪ Cell anchorage and cell migration ▪ Maintain cell polarity ▪ Control of Cell Proliferation ▫ Provide growth signals and constraints ▪ Scaffolding for tissue renewals ▫ Intact ECM is crucial for the regeneration of tissues ▪ Establishment of tissue microenvironments ▫ Interstitial space accumulates cell signaling molecules 52 ▪ primarily cell-matrix adhesion but also in some cell-cell adhesions ▪ Homologous transmembrane cell-matrix adhesion receptor ▪ Homologous – formed by multiple polypeptides of same/similar structure ▪ Transmembrane – cross the membrane ▪ Receptor - receiving something. ECM this time Integrins ▪ Alpha subunit and beta subunit ▪ Forms a groove Structure of Integrins ▪ Binds ECM with low affinity ▪ Binding is Ca2+ / Mg2+ dependent ▪ Bind with actin/filament Extracellular domain Transmembrane domain Cytoplasmic domain Molecular Biology of the Cell. 4th edition. Alberts B, Johnson A, Lewis J, et al. New York: Garland Science; 2002. ▪ Integrin is cell-specific  large family 53 54 ▪ Adhesion Junction ▪ Adherens junction ▪ Desmosome Types of Cell – Cell Junction ▪ Tight Junction ▪ Communication Junction ▫ Gap junction ▫ Plasmodemata ▪ Cell – Matrix Junction ▫ Hemidesmosome ▫ Actin-linked cell-matrix Junction 55 56 ADHESION JUNCTIONS COMMUNICATING JUNCTIONS Molecular Biology of the Cell 6th Edition 57 Adhesion Junction 58 https://www.mechanobio.info/what-is-mechanosignaling/what-are-cell-cell-adhesions/ 59 ▪ Adherens junction Adherens Junction ▪ Found in most multicellular organisms ▪ Linking cells by binding to actin (adhesion belt) ▪ Response to pulling force ▪ Coordinate actin movements ▪ Affect cell shape and orientation ▪ Coordinate tissue remodelling 60 Tissue Remodelling ▪ Coordinated contraction of adhesion belt ▪ Changing orientation Molecular Biology of the Cell 6th Edition 61 ▪ Desmosomes Desmosomes ▪ Found in vertebrates only ▪ Linking cells by binding to the intermediate filament ▪ Forming a 3D network of intermediate filament ▪ Provide mechanical strength to epithelial cells 62 Provide Mechanical Strength ▪ Linking intermediate filament ▪ Form a 3D filament network Molecular Biology of the Cell 6th Edition 63 Molecular Biology of the Cell 6th Edition 64 Component & Structure of Adhesion Junction 65 Cadherin Family ▪ Major junction molecules (CAM) ▪ Multiple domain ▪ EC  Extracellular Domain https://www.researchgate.net/figure/Classical-cadherin-structure-and-model-of-homophilic-binding-a-The-classical-cadherins_fig1_227220621 Molecular Biology of the Cell 6th Edition 66 Cadherin Superfamily ▪ Major junction molecules (CAM) ▪ Multiple domain C-terminal N-terminal 67 ▪ Classical cadherin (similar sequence) ▪ E-cadherin (epithelial cell) ▪ N-cadherin (nerve cell) ▪ P-cadherin (placenta) ▪ Non-classical cadherin (diverse seq) ▫ Brain cell (> 50 member) Members of Cadherin Superfamily 68 Features of Cadherin Superfamily ▪ Calcium dependent (Cadherin) ▪ “Calcium-dependent Adhesion” ▪ Usually homophilic binding instead of heterophilic binding ▪ Homophilic binding leading symmetrical anchoring junctions 69 ▪ Calcium dependent (Cadherin) Features of Cadherin Superfamily With Calcium Without Calcium Molecular Biology of the Cell 6th Edition 70 Features of Cadherin Superfamily Molecular Biology of the Cell 6th Edition ▪ Usually homophilic binding instead of heterophilic binding ▪ Both cells are identical ▪ Both cells are different ▪ Common in cell adhesion molecules ▪ Common in cell recognition molecules ▪ (e.g. Cell-ECM adhesion) 71 Tight Junction 72 ▪ Forming seal between cells Tight Junction ▪ ▪ Separating fluid on the two sides of a cell ▪ Provide selective permeability A fence of the plasma membrane ▫ Maintaining the difference in the distribution of cell surface protein on the plasma membrane 73 Blocking fluid from the lumen of the intestine flow to the inside of villus Cell surface protein of the two sides cannot diffuse to the other side Molecular Biology of the Cell 6th Edition 74 Structure of Tight Junction ▪ Claudin is primary and essential ▪ Occludin is not essential but important for limiting permeability Molecular Biology of the Cell 6th Edition 75 Gap Junction 76 ▪ Forming communication channel between two cells ▪ Linking the cytoplasm between two cells ▪ Allow passing of small water-soluble molecules ▪ Signalling between two cells mediates by Gap Junction ▪ ▪ Ca2+ concentration pH 77 78 Structure of Gap Junction ▪ Connexins (multiple members) ▪ Six connexins form one hemichannel (connexon) ▪ Multiple connexon aggregate and form a molecular sieve ▪ Different members of connexins provide different selectivity and permeability 79 Structure of Gap Junction Selectivity and permeability depends on connexins combination Molecular Biology of the Cell 6th Edition Topic 4 Cell Division and Programmed Cell Death (Part – 1) Chromatin, Chromatid & Chromosomes Chromatin refers to a mixture of DNA and proteins that form the chromosomes found in the cells of humans and other higher organisms https://www.sciencesfp.com/cells-and-inheritance.html https://micro.magnet.fsu.edu/cells/nucleus/chromatin.html 82 1hr 23hr The Cell Cycle  The mitotic phase alternates with interphase in the cell cycle  Interphase  mitosis  interphase  mitosis Interphase can be divided into subphases  G1 phase (GAP 1 phase)  cell grows in size  varies most in length from cell to cell  S phase (synthesis phase)  DNA is copied (DNA replication)  Single  Double  Other organelles are copied (ex: centrosomes in animal cells)  G2 phase (GAP 2 phase)  More growth and preparation (make proteins) for mitosis http://www.cellsalive.com/cell_cycle.htm Another G phase of Interphase ▪ ▪ ▪ Called G0 phase called the resting phase The cell exits the “cycle” and (usually) does NOT reproduce again E.g. muscle cells, nerve cells, red blood cells Interphase “Intermission” or “Inbetween” ▪ not part of mitosis Includes stages G1, S, and G2 of the cell cycle DNA is in chromatin form Nucleus & nucleolus present ▪ Longest phase of cell cycle ▪ ▪ ▪ The Mitotic (M) phase  Is made up of 2 parts 1. Mitosis division of the nucleus (called Karyokinesis) 2. Cytokinesis  division of the cytoplasm Mitosis ▪ ▪ Continuous pathway (Early, Mid, & Late) Consists of 4 phases and cytokinesis ▫ Prophase ▫ Metaphase ▫ Anaphase ▫ Telophase ▫ Cytokinesis Prophase “Pack Together” ▪ Chromatin  Chromosomes ▫ ▪ DNA “packs” together Mitotic spindle fibres form from centrosomes ▫ Centrioles are in centrosomes in animals ▫ ▫ appear as asters in animals Microtubule Organizing Centers (MTOC’s) (in plants) Centrosomes & Spindle fibres move towards “poles” ▪ Late: Nucleus and nucleolus disappear ▪ kinetochore fibres attach to each kinetochore on each chromosome  they begin to migrate toward the cell centre Mitotic Spindle Fibers  Two types of spindle fibers 1. Kinetochore fibers 2. Polar fibers  Kinetochores generate fibers that attach sister chromatids to spindle fibers.  Kinetochore fibers and spindle polar fibers work together to separate chromosomes during mitosis and meiosis. Spindle fibers that don't contact chromosomes during cell division G2 OF INTERPHASE PROMETAPHASE PROPHASE Aster Centrosomes (with centriole pairs) Chromatin (duplicated) Early mitotic spindle Centromere Fragments of nuclear envelope Kinetochore Nonkinetochore microtubules Figure 12.6 Nucleolus Nuclear envelope Plasma membrane Chromosome, consisting of two sister chromatids Kinetochore microtubule Metaphase “Meet in the Middle”   Chromosomes line up in the middle of cell  Called equatorial or metaphase plate Spinder fibers pull chromosomes to line up SAME IN PLANTS AND ANIMALS Anaphase “Away” ▪ ▪ ▪ ▪ SISTER CHROMATIDS separate and begin moving to opposite ends (poles) of the cell Polar fibers lengthen and elongate the cell Late anaphase  each pole contains a complete set of single chromosomes NOTE: This is the only time there is DOUBLE the amount of DNA in ONE cell SAME IN PLANTS AND ANIMALS NOT CHROMATIDS NOW!!! METAPHASE ANAPHASE Metaphase plate Figure 12.6 Spindle Centrosome at one spindle pole TELOPHASE AND CYTOKINESIS Cleavage furrow Daughter chromosomes Nuclear envelope forming Nucleolus forming Telophase “Two New Cells”  Spindle fibers disappear  2 daughter nuclei  2 nucleoli begin to form at each pole  Chromosomes  chromatin OPPOSITE OF PROPHASE Cytokines is “Division of the Cytoplasm”     Occurs in Late telophase In animal cells  a cleavage furrow forms, which pinches the cell in two. In plant cells  vesicles from the Golgi apparatus produce a cell plate at the middle of the cell At the end of cytokinesis, there are two distinct IDENTICAL daughter cells. Cytokinesis  Cleavage furrow Contractile ring of microfilaments Figure 12.9 A 100 µm Daughter cells (a) Cleavage of an animal cell (SEM) In animal cells  Cytokinesis occurs by a process known as cleavage, forming a cleavage furrow ▪ In plant cells, during cytokinesis ▫ A cell plate forms Vesicles forming cell plate Wall of patent cell 1 µm Cell plate New cell wall Daughter cells Figure 12.9 B (b) Cell plate formation in a plant cell (SEM) G2 OF INTERPHASE PROMETAPHASE PROPHASE Aster Centrosomes (with centriole pairs) Chromatin (duplicated) Early mitotic spindle Centromere Fragments of nuclear envelope Kinetochore Nonkinetochore microtubules Figure 12.6 Nucleolus Nuclear envelope Plasma membrane Chromosome, consisting of two sister chromatids Kinetochore microtubule METAPHASE ANAPHASE Metaphase plate Figure 12.6 Spindle Centrosome at one spindle pole TELOPHASE AND CYTOKINESIS Cleavage furrow Daughter chromosomes Nuclear envelope forming Nucleolus forming Meiosis - Sex Cell (Gamete) Formation In meiosis, there 2 are divisions of the nucleus: meiosis I & meiosis II Image: Overview of Meiosis, National Institutes of Health From the Virtual Cell Biology Classroom on ScienceProfOnline.com From the Virtual Cell Biology Classroom on ScienceProfOnline.com Image: Meiosis diagram, Marek Kultys Genetic Variation in Diploid Organisms Fusion of sperm and egg results in unique offspring… …but not only because the young are a product of two individuals with different genetic makeup. Meiosis also “shuffles” the genes so that the an individual’s gametes are genetically different from one another. How is this shuffling accomplished? From the Virtual Cell Biology Classroom on ScienceProfOnline.com Image: Meiosis diagram, Marek Kultys Genetic shuffling of Meiosis I In addition to a new combination of chromosomes resulting from fertilization, there are also events in Meiosis I that shuffle the genes. 1. Crossing over in Prophase I. 2. Independent assortment in Metaphase I. From the Virtual Cell Biology Classroom on ScienceProfOnline.com Crossing Over ▪ Homologues break at identical locations, then rejoin opposite partners. ▪ This creates new combinations of the alleles on each chromosome. ▪ Occurs randomly several times on every chromosome. ▪ Results in mixing of the genes you inherited from your parents. From the Virtual Cell Biology Classroom on ScienceProfOnline.com Independent Assortment Maternal set of chromosomes Paternal set of chromosomes Variation from genetic recombination ▪ Independent assortment of chromosomes ▫ meiosis introduces genetic variation ▫ gametes of offspring do not have same combination of genes as gametes from parents ▫ random assortment in humans produces 223 (8,388,608) different combinations in gametes from Mom from Dad offspring new gametes made by offspring Mitosis Meiosis vs. ▪ 2n ▪ 1n ▪ Clone ▪ ▪ Same genetic information in parent cell and daughter cell. Daughter cells different from parent cell and from each other. ▪ Daughter cells have ½ the number of chromosomes as somatic cell. ▪ Shuffling the genes ▪ Give me another one just like the other one! (Mix it up!) From the Virtual Cell Biology Classroom on ScienceProfOnline.com