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BIO 1P03 REVIEW.docx

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Department
Biology
Course
BIOLOGY 1P03
Professor
Lovaye Kajiura
Semester
Fall

Description
Biology 1P03 Fall 2012 Notes Chapter One – An Introduction to Life on Earth Cells: smallest unit of life Cells Tissues  Organs  Organ Systems  Population  Species  Community  Ecosystems  Biosphere Scientific inquiry is based on the assumption that people perceive natural events in similar ways – unique to science Living vs. Non Living 1. Living things are composed of cells that have a complex organized structure 2. Living things actively maintain their complex structure 3. Living things respond to stimuli 4. Living things acquire and use materials and energy from their environment 5. Living things grow 6. Living things reproduce themselves using the molecular blueprint of DNA 7. Living things use DNA to store information Homeostasis: organisms must regulate amount of water and salt and maintain an appropriate temperature Autotrophic: self-feeding organisms (photosynthesis) Heterotrophic: other feeding (carnivore, omnivore) Chapter Two – Atoms, Molecules and Life C, O, H, N  makes up 95% of living things || Ca, P, K, S, Na, Cl, Mg + trace elements  reaming 4% Atomic nucleus: contains positively charged protons and uncharged neutrons  negatively charged neutrons circle atom  Atomic number = number of protons  Atomic mass = total mass of protons and neutrons Types of Bonds Ionic bonds: (hydrophilic) electrical attraction between positively and negatively charged ions – broken apart by water Covalent bonds: the sharing of electrons between uncharged atoms  If the electrons are shared roughly equally, poles are uncharged = non polar (hydrophobic)  If the shared electrons spend more time near one of the atoms, one pole is slightly negative while the other is slightly negative = polar (hydrophobic) Hydrogen bonds: attraction between slightly positive hydrogen in a polar molecule and the slightly negative pole of a nearby polar molecule  works with N, O, F  takes a lot of energy to break apart Buffers: maintain a solution at a constant pH by the addition or removal of H ions Chapter Three – Biological Molecules Organic molecules: carbon skeleton bonded to some hydrogen atom  functional groups help determine the characteristics and chemical reactivity Group Structure Properties Found In Hydroxyl Polar; involved in Sugars, starches, dehydration and nucleic acid hydrolysis Carbonyl Polar; tends to Amino acids, fatty make parts of acids molecules hydrophilic (water-soluble) Carboxyl Acidic; the Amino acids, negatively nucleic acids charged oxygen + may bond H , forming carboxylic acid (- COOH); involved in peptide bonds Amino Basic; may bond Amino acids, an additional H , nucleic acids becoming positively charged; involved in peptide bonds Sulfhydryl Forms disulfide Some amino acids; bonds in proteins many proteins Phosphate Acidic; links Nucleic acids, nucleotides in phospholipids nucleic acids; energy-carrier group in ATP Dehydration synthesis: a chemical reaction that joins biological molecules  H+ ion is removed for one subunit and a OH ion is removed from a second subunit leaving openings where atoms share electrons Hydrolysis: opposite of dehydration synthesis – splits the molecule back into its original subunits Chapter Four – Cell Structure and Function Cell Theory 1. All cells come from previously existing cells 2. Every living organism is made up of one or more cells 3. The smallest living organism are single cells, and calls are the functional units of multicellular organisms Parts of the Cell and their Function:  Plasma Membrane: encloses the cell and allows interactions between the cell and its environment  regulates the flow of materials into and out of the cell  Cytoplasm: all the fluid and structures that lie inside the plasma membrane but outside the nucleus  contains water, salts and an assortment of organic molecules (proteins, lipids, carbohydrates, sugars, am most of the cellsotides) metabolic activities occur in the cell cytoplasm  DNA (deoxyribose nucleotide): used as a blueprint for making the other parts of the cell and new cells  Cytoskeleton: composed of 3 types of protein fibers; microfilament(thin fiberintermediate filaments (medium sized and microtubules (thick fbers) functions include; cell shape, cell movement, organelle movement, cell division  Nucleus: Main control center – consists of 3 parts: nuclear envelope, chromatin and the nucleolus  Nuclear Envelope: double membrane – isolates the nucleus from the rest of the cell  Nuclear Pore Complex: regulates the passage of large molecules into the nucleus  DNA must stay in nuclear envelope  Nucleolus: site of ribosome synthesis  Ribosome: small particle composed of ribosomal RNA and proteins that serve as a “workbench” for the synthesis of proteins  Smooth Endoplasmic Reticulum: lacks ribosomes and is specialized for different activities in different cells  Rough Endoplasmic Reticulum: sites if protein synthesis – ribosome embedded  Golgi Apparatus: sorts, modifies and packages produced proteins  vesicles are transported to other parts of the cell or to the plasma membrane  Lysomes: enzymes enclosed in membrane enclosed vesicles  used to help digest food particles in combination with the food vacuole  Central Vacuoles: filled mostly with water – provides a dump site for hazardous wastes – poison may be kept there to deter animals  Mitochondria: use energy from food molecules and store in high energy bonds of ATP – aerobic – the breakdown of food with oxygen, generates more energy  Chlorophyll: captures the energy of the sunlight and transfers it to the other molecules Eukaryotic Cells: - complex and comprise the bodies of animals, plants, fungi and protists Prokaryotic Cells: - genetic material is not enclosed by a membrane – simple in shape, very small How are Proteins Secreted? 1. Secretory protein is manufactured on ribosomes of the rough ER 2. Protein is packed into vesicles that are formed from the ER membrane and that travel to the Golgi 3. Protein is released into the Golgi and carbohydrates are attached 4. Protein is repackaged into vesicles in the Golgi membrane and travel to the plasma membrane where the secretory protein is released Chapter Five – Cell Membrane Structure and Function Cell Membrane:  Boundary between living and non-living  Selective barrier  Allows communication between cells  Create attachments within and between cells Cell Membrane Structure: proteins floating in a double layer of phospholipids Phospholipid Bilayer  Phospholipids arranged into a double layer – hydrogen bonds form between water and hydrophilic heads  Non polar hydrophobic tails inside bilayer – polar, hydrophobic, non fatty heads inside  Cholesterol stabilizes the lipid bilayer Membrane Proteins o Receptor proteins – respond to messages sent by other cells o Recognition proteins - serve as identification tags o Enzymatic proteins – promote chemical reactions that synthesize or break apart biological molecules o Attachment proteins – anchors cell membranes in various ways o Transport proteins – regulate the movement of hydrophilic molecules through plasma membrane o Channel proteins – form channels whose central pores allow water molecules or specific ions to pass through the membrane along their concentration gradients o Carrier proteins – have binding sites that can temporarily attach to specific molecules on one side of the membrane Simple diffusion: diffusion directly across the phospholipid bilayer down their concentration gradient – very small molecules with no net charge Facilitated diffusion: molecules with hydrogen bonds do not enter the bilayer – diffuse across membrane only with the aid of specific transport proteins: channel or carrier proteins Active Transport: membrane proteins use ATP to move molecules or ions across the plasma membrane against their concentration gradients Osmosis: movement of water across a selectively permeable membrane in response to gradients of concentration, pressure or temperature Isotonic: solutions with equal concentrations of solute and water – water enters and leaves equally – plant: flaccid Hypotonic: dilute solution – more water coming in than leaving – trying to increase concentration – plant: turgid – animal: lyse Hypertonic: greater concentration of solute – less water entering than leaving – trying to dilute the concentration – plant: plasmalized – animal: crenate Endocytosis o Pinocytosis: a very small patch of plasma membrane dimples inward as it surrounds unspecified substances o Receptor-mediated endocytosis: relies on specialized receptor proteins located on the plasma membrane in thickened depressions called coated pit – pocket pinches off into a dimple o Phagocytosis: pick up large particles, including whole microorganisms – feeding Exocytosis: use of energy to dispose of undigested particles of waste or to secrete substances Attachment Structure o Desmosomes: membranes of adjacent cells are tacked together by a complex of different attachment proteins o Tight junction: leak proof barrier – two membranes stitched together Communication Structure o Gap junction: channel proteins connect the insides of nearby cells o Plasmadesmata: holes in the walls of adjacent plant cells – membrane -lined channels connect the insides of adjacent cells Chapter Nine – Cell Reproduction Genes: segments of DNA ranging from a few hundred to many thousands of nucleotides long Sexual reproduction: in eukaryotic organisms occurs when offspring’s are produced by the fusion of gametes Asexual reproduction: single parent – genetically identical offspring Prokaryotic Cell Cycle Binary fission: DNA replicates and attaches to plasma membrane  plasma membrane pushes them apart and grows inward  cells split DNA in Eukaryotic Chromosomes  Information is encoded in the DNA that contain the genes Locus: each gene occupies a specific place on a chromosome Telomeres: essential for chromosome stability – two ends of chromosome consists of repeated nucleotide sequences Centromere: temporarily holds two daughter DNA double helices together after DNA replication + attachment site for microtubules that move chromosomes during cell division Duplicated chromosomes = sister chromatids Homologous chromosomes: chromosomes that contain the same genes – cells with pairs of these are diploids Mutations: make on homologue a little different genetically, than its pair  Cell division is required for growth, development and repair Eukaryotic Cell Cycle Mitosis Cell Division Interphase G1– cell growth and differentiation S – synthesis of DNA: chromosomes are duplicated G2– Cell growth and preparation for cell division Prophase: formation of spindle fiber Metaphase: chromosomes attach onto spindle fibers and line up on metaphase plate (equator of the cell) Anaphase: sister chromatids separate and move to opposite poles of the cell Telophase: nuclear envelopes from around both groups of chromosomes Cytokinesis: the cytoplasm is divided between two daughter cells Meiotic Cell Division (reproduction) Meiosis I Prophase I – homologous chromosomes pair up  chiasmata: mixing of chromosomes from mom and dad Metaphase I – paired homologues lines up at the equator of the cell Anaphase I – homologous chromosomes separate Telephase I and cytokinesis – two haploid daughters Meiosis II separates sister chromatids into four haploid daughter cells Prophase II – nuclear envelope breaks down again Metaphase II – chromosome line up at equatorial plate and attach spindle fibers Anaphase II – chromosomes separate – unattached spindle fibers create a cage so the cell does not collapse Telephase II and Cytokinesis II – separation of cytoplasm * MEIOSIS I = 2 cell, MEIOSIS II = 4 cell * Genetic Variability  Shuffling of homologues creates novel combination of chromosomes  Crossing over creates chromosomes with novel combinations of genetic material  Random fusion of gametes creates genetic variable offspring Chapter 10 – Patterns of Inheritance Locus: genes physical location on a chromosome Homozygous: both homologues have the same allele at a given gene locus Heterozygous: two homologous chromosomes have different alleles at a locus Hybrids: organisms that are heterozygous at a specific locus Self-fertilization: when an organism’s sperm fertilizes its own eggs Cross-fertilization: when sperm from one organism fertilizes eggs from a different organism True-breeding: organisms that possess a trait that is always inherited unchanged by its entire offspring that are produced by self-fertilization Law of Segregation: the pairs of alleles on homologous chromosomes separate or segregate from each other during meiosis Genotype: the actual combinations of alleles carried by an organism Phenotype: organism’s traits, including outward appearance, behavior, blood type or any other observable or measurable feature Law of Independent Assortment: independent inheritance of two or more traits  Genes on the same chromosome tend to be inherited together  linkage  traits tend to stay together in meiosis – crossing over can change linkage Incomplete dominance: not fully dominant over the recessive gene – intermediate of the parental type Codominance: one foes not dominate the other, both have impact – both alleles are active Polygenic inheritance: a form of inheritance in which the interaction of two or more genes contributes to a single phenotype Pleiotrophy: single genes commonly have multiple phenotypic effects Nondisjunction: gametes that have too many or too few chromosomes Gregor Mendel - Controlled breeding, selected true-breeding parents - Prevented self fertilization of pea plants by removing male reproductive organs from the flowers - Permitted cross-fertilization by using pollen from a different plant - Studied 7 characters, for, each he observed contrasting forms - Carefully counted the offspring and kept detailed records of his experiments Monohybrid cross: cross between two parents that are heterozygous for a specific gene Punnett Square Abnormal number of sex chromosomes Disorders Turner Syndrome (XO) – female – only viable human monosomy – short stature, webbed neck – shield like chest – internal sex organs not mature – sterile Trisomy X (XXX) – female – usually normal phenotype and fertile, others have variable expression Klinefelter Syndrome (XXY) – male – large hips and breast development – smaller should
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