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Biology 1001 Exam Review 11.doc
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Department
Biology
Course
BIOL 1000
Professor
Nicole Nivillac
Semester
Fall

Description
Jenkin Tsang G11 2011-2012 Biology Exam Review Diversity of Life Biodiversity Biodiversity – The variety of life in the world 3 levels of biodiversity Genetic Diversity – Sum of all different forms of genes present in particular species Genetic diversity allows populations to adapt to changes in environmental conditions and evolve over time Lack of genetic diversity in British bumblebee populations = inbreeding - Infertile males - More susceptible to diseases carried by parasites than healthy populations Species Diversity – Variety of species and relative abundance of species in a given area Ecosystem Diversity – Diverse range of habitats, various organisms that in habitats, and relationships that connect them Threats to Biodiversity 1. Over-hunting/ Over-fishing Whales, large African animals, passenger pigeons 2. Habitat Loss - The more specific an organism’s food needs are, the more vulnerable it is to becoming extinct/endangered through loss of habitat - Tropical forests contain + 50% of world’s biodiversity - Difference between fragmentation and habitat loss: fragmentation is when a habitat is left in small isolated bits rather than in large intact units, while habitat loss is when the habitat is physically destroyed. 3. Invasive Species How did Nile Perch affect African Great Lakes – They ate all the native fish 4. Climate Change “Distribution of species” (aka biogeography) is largely determined by climate, so if the climate changes, the organisms living in the area have to cope with the change, however, if unable to do so, they will die or move outJenkin Tsang G11 2011-2012 Benefits 4-sustaining services biodiversity provides: - Pollination of flowers, crops, and plants - Breaking down toxins - Purification (Recycling of CO 2) - Moderate climate Taxonomy Up to 1.6 million types of organism identified on Earth We use characteristics such as cell structure, structural characteristics, methods of obtaining nutrition, and degree of genetic similarity. The Linnaean System - Published in 1735, Swedish naturalist – Carolus Linnaeus - System known as binomial nomenclature grouped organisms according to structural similarities - The names are based on characteristics such as color or habitat - The first part of the name refers to genus, small group of related species. Always CAPTALIZED - 2 part is the species name Classification Different groups which organisms are called taxa and the science of classifying is called taxonomy Smallest taxon is species A species is a group of organisms that can interbreed and produce viable offspring Similar species make up a genus (plural: genera) Similar genera make families Largest category is kingdom 6 kingdoms of life: Eubacteria, archaebacteria, protista, fungi, plantae, animalia 6 main ways to separate organisms into kingdoms 1. Cell type a. Prokaryotic (lack of nucleus) b. Eukaryotic 2. How they acquire food a. Heterotrophic - Needs to acquire food b. Autotrophic – Synthesizes foodJenkin Tsang G11 2011-2012 3. How they reproduce a. Asexually – Offspring identical to parent b. Sexually – Offspring have similarities from both parents 4. Habitat (Where they live) a. Terrestrial – Land b. Aquatic – Water c. Other – Extremes: salty, hot, acidic 5. Cellular Make-up a. Multicellular – Cell specialization b. Unicellular – One celled creatures 6. Presence of a cell wall How Reproduction Kingdom Cell they Habitat Cellular Cell Examples Typ acquir Make- Wall e e food up Eubacteria P Both A T & A U Y – E coli PDG Archaebacteri P Both A E U Y – Extremophilos a no PDG Protista E Both Both Mostly M N Seaweed A Fungi E H Both T M Y Mushrooms Plantae E A Both T & A M Y Fern Animalia E H Both T& A M N Llama King (Kingdom) Phillip (Phylum) Cooks (Class) Ostriches (Order) For (Family) Grandma’s (Genus) Supper (Species) Bacteria Traditional antibiotics work in two ways, by popping the cell membrane, or preventing reproduction. Bacteria can build resistance to these invaders Properties 1. Classified into two kingdoms: Eubacteria (true bacteria) and Archaebacteria (Ancient Bacteria) 2. Bacteria are the MOST NUMEROUS ORGANISMS ON EARTH 3. Organisms are classified as bacteria b one characteristic: lack of a cell nucleus (“prokaryote” means “before a nucleus”) 4. Outer cell wall made of petidoglycan (PDG) 5. Some move by means of flagella (singular flagellum)GRAM-NEGATIVE Pilus Flagellum A Cell wall Cell membrane Outer membrane Peptidoglycan cytoplasm DNA Ribosomes GRAM-POSITIVE Pilus Flagellum Ce Cell wall membrane GRAM-NEGATIVE Pilus Flagellum A Cell wall Cell membrane Outer membrane Peptidoglycan cytoplasm DNA Ribosomes GRAM-POSITIVE Pilus Flagellum Ce Cell wall membraneJenkin Tsang G11 2011-2012 6. Fimbrae – fibres that stick to surfaces (tooth decay, gonorrhoea) 7. Region called the NUCLEOID which has a single circular chromosome, accessory rings of DNA called PLASMIDS (which contains few genes, have a role in conjugation [cell sexual reproduction]) 8. Bacteria are extremely small - Prokaryotic [μm - 10 μm] - Eukaryotic [10 μm - 100 μm] Shape of Bacteria/Naming Cocci – sphere Bailli – rods Spirilla – Spiral Mono – cells that live as individuals Diplo – cells that exist in pairs Staph – in clusters Strep – in chains *Spirilla can only exist as single cells Nutrition & Needs Obligate anaerobes – Cannot grow in the presence of oxygen Facultative anaerobes –can grow with or without oxygen Aerobic – require oxygen Photoautotrophs – photosynthetic Chemoautotrophs – obtain organic energy from oxidizing inorganic compounds, such as ammonia Chemoheterotrophs- decomposers Gram Staining Developed by Hans Christian Joachim gram as a method of identifying bacteria Differentiates between two major cell way types - Bacteria with walls containing small amounts of peptidoglycan are Gram negative (Light red/pink) - Bacteria with walls containing large amounts of peptidoglycan are Gram positive (Dark purple)Capsule Cell Wall Cytoplasmic Membrane Ribosomes Photosynthesis Pili Help attach to other bacteria role in conjugation Cell Structure Cytoplasm Nucleoid Flagella Cell wall Plasma membrane Cell elongates and DNA (nuclear area) DNA is replicated Bacterium Mobile Plasmid Pius Chromosome Donor Recipient 01 New Donor New Donor Capsule Cell Wall Cytoplasmic Membrane Ribosomes Photosynthesis Pili Help attach to other bacteria role in conjugation Cell Structure Cytoplasm Nucleoid Flagella Cell wall Plasma membrane Cell elongates and DNA (nuclear area) DNA is replicated Bacterium Mobile Plasmid Pius Chromosome Donor Recipient 01 New Donor New DonorJenkin Tsang G11 2011-2012 Reproduction Occurs by Binary Fission (mitosis) and Conjugation (exchange of DNA) Endospores – formed during unfavourable conditions, bacteria enclosed in a protective coat (Bacterial Hibernation) Binary Fission – Asexual Reproduction Product: 2 identical daughters Conjugation - Sexual Reproduction - Only used in times of stress 1) Resources (food & water) 2) Attack (viral, antibiotic)Jenkin Tsang G11 2011-2012 3) Environment (drought, temperature changes) Protists They appeared about 1.5 billion years ago and they are all eukaryotic organisms. Animal Like Protists -often called protozoans (meaning first animal) because they eat or ingest material from their surroundings Zooflagellates: possess more or more flagella which is used to move through the water. Some zooflagellages are heterotrophic, others live as internal parasites and others are pathogens meaning they cause diseases or illnesses Amoebas: single celled organisms with no body shape that create temporary projections of the cytoplasm called pseudopods to move and feed Ciliates: -covered with hair like projections called cilia which moves back and forth to move organism through the water as well as sweeps food into its oral groove. Sporozoams: produce spores during asexual phase of reproduction. The best known sporozoans are from the genus Plasmodium which cause malaria and are carried by the female Anopheles mosquito Fungus like Protists They are all heterotrophic and most are decomposers that feed on dead plants and animals Plant like Protists -contain chlorophyll and carry out photosynthesis Euglenoids: unicellular flagellates but many carry out photosynthesis Algae: resemble plants because they have chloroplasts and contain the pigment chlorophyll Diatoms: have glasslike shells made of silica. They are abundant in oceans and are a key food source in aquatic ecosystems Dinoflagellates: have two flagellas and are abundant in freshwater andJenkin Tsang G11 2011-2012 marine environments. They grow rapidly when nutrients in water increase or ocean temperatures rise. The rapid population growth is called a bloom What is red tide and why is it harmful? Red tide occurs when dinoflagellate Gonaulax polyhedron blooms. This is harmful because they produce toxins which build up in organisms and cause death due to the heavy concentration as the toxins movie up the food chain. Green Algae: ancient green algae are thought to have given rise to the first plants because they have cellulose in their walls and because they have similar chloroplasts. Algae performs 50% - 75% of all photosynthesis on Earth. Fungi Characteristics: Fungi are heterotrophic eukaryotic organisms that are saprobes meaning they are decomposers. They absorb food from decaying matter and release digestive enzymes that breakdown dead organic matter which is then absorbed through the cell wall. The bodies of fungi are comprised of threadlike filaments called hyphae which grow and branch to form a mass of filaments called mycelium. The difference between the cell wall of fungi and plants is a substance called chitin, which strengthens the cell wall of fungi rather than cellulose in plants. Plants -Appeared about half a billion years ago General Characteristics: -Eukaryotic, multicellular organisms that carry out photosynthesis. Cell walls contain cellulose -plants go through an alternation of generations, one generation is haploid and the other is diploid. These are called gametophyte and sporophyte generations -animals such as humans are diploid throughout their entire lives -Plants produce haploid reproductive cells called spores. A spore will undergo cell division to grow into a new plant -Haploids produce gametes which fuse to form a diploid zygote. The zygote then grows into a diploid sporophyte plant Non Vascular Plants: -Bryophytes include mosses, liverworts and hornworts -they lack true roots, stems and leaves and do not have specialized tissues to transport materials throughout the plant body -Can reproduce asexually by vegetative reproduction or sexually Vascular Plants:Jenkin Tsang G11 2011-2012 What is the main difference between vascular and non-vascular plants? Vascular plants have conducting tissue. There is the presence of xylem and phloem which transport materials throughout the plant -vascular plants are grouped into two group: spore producing and seed producing plants Spore producing vascular plants: -club mosses, horsetails and ferns Seed producing vascular plants: -most successful plants on earth have specialized organs namely leaves, stems and roots -two main groups produce either cones or flowers Gymnosperms: -include conifers, gnetae, gingkos and cycads -have specialized reproductive structures called cones Anglosperms: -reproduce sexually by means of flowers through the process of pollination -seeds are contained in a protective wall that develops into a fruit Viruses Viruses are non-living particles that cannot carry out metabolic functions (produce ATP) or reproduce without a host. They are fairly small ranging from 20 nm to 400 nm and since they are non-living, antibiotics have no effect on them. Bateriophage: Viruses that infect bacteria Reproductive Cycles There are two cycles that viruses can undergo: The Lytic Cycle or the Lysogenic Cycle The Lytic Cycle is what most viruses go through. In this process, the virus attaches onto a cell and enters the host cell. Using the cell’s resources, the virus assembles new viruses and once they are complete, they are released. 1-2) Attachment and EntranceJenkin Tsang G11 2011-2012 3) Host DNA digested 4) Phage (virus that reproduces itself in bacteria) DNA is made using the nucleotides from former host DNA 5) Host cells transcribes the phage DNA into phage proteins 6) Assembly of new viruses 7) Lysis: release of new virus/ the cell dyes Lysogenic Cycle, the virus attaches to the cell and enters. But rather than taking over, it simply transfers its DNA, integrating it into the bacterial/cell chromosome. When this cell undergoes cell division, the chromosome with integrated prophage replicates which continues for many cell divisions. Sometimes (but very rarely) the virus may separate and enter the lytic cycle. 1) Virus enters bacteria 2) Inserts its DNA into the host’s DNA Viruses are very selective, specific viruses enter only specific cells. This is called the host range. Influenza: narrow host range, infects cells of upper respiratory track HIV: narrow host range, infects a type of white blood cell RNA Viruses Protein Synthesis: RNA viruses can act in two ways: 1.) RNA acts as mRNA 2.) They can provide instructions to make their own mRNA • Retroviruses use the enzyme reverse transcriptase to make DNA from RNA • The host cell does not burst (lysogenic cycle) but changes in shape, metabolism and growth pattern Genetic Continuity Mitosis Organization of Genetic Material (DNA->Chromosome) Chromatin condenses into chromatids Chromatids join in pairs to form chromosomes (the 2 chromatids are sister chromatids)(M) HASE INTERPHASE (DNA synthesis) (M) HASE INTERPHASE (DNA synthesis)Jenkin Tsang G11 2011-2012 Cell Cycle 1. Interphase (cell doing cell things) i. 1 phase: cell is growing and preparing for replication ii. S phase: DNA is replicated iii.2G phase: preparation for mitosis 2. Mitosis (division of the nucleus) - Prior to mitosis, chromosomes are spread thinly throughout cell, and is called chromatin - After Interphase, chromosomes have duplicated • Each identical strand is called a chromatid • The chromatids are held together at the centromere Phases of Mitosis (PMAT) Prophase Chromatin condenses into chromosomes Nuclear envelope disappears Metaphase Chromosomes align at equatorial plate Anaphase Sister chromatids separate Centromeres divide Telophase Chromatin expands Cytoplasm dividesJenkin Tsang G11 2011-2012 Germ Cells vs. Somatic Cells Germ cells (sex cells) only have 23 chromosomes while Somatic cells have 23 pairs of chromosomes (46 identical chromosomes) The complete set of chromosomes is called the diploid number, half of the set is the haploid number Differentiation causes different types of cells to synthesize protein from certain sections of the DNA Mitosis and Cancer Cancer stars when a cell divides uncontrollably, forming a tumor, or a mass of cells. Meiosis Chromosome number, homologous chromosomes, fertilization alleles - Humans have 46 chromosomes - This is called the diploid number (2n) • 23 maternal (mom) and 23 paternal (father) - Meiosis produces gametes (sperm + egg) with half the chromosomes of the diploid number - Called the haploid number, n - Fertilization occurs when the sperm and egg join to make a single diploid cell, the zygote Characteristics of Homologues: - Same size, shape, position of centromere - Same genes: segments of DNA that carry code for specific traits (e.g. hair color) - Genes aren’t always identical (e.g. one gene may code for blond hair and another for brown hair) - Different forms of the same gene are called alleles - Genes are at the same loci (location on the chromosomes) Purpose: production of sex cells To produce gametes for sexual reproduction later Stages of meiosis: sources of genetic variation Sperm are produces in spermatogonia (diploid cell) in the testes Eggs are produced in oogonia in the ovariesJenkin Tsang G11 2011-2012 Male produces 4 sperm cells, Female produces 1 egg and 3 polar bodies (useless cells) Genetic Variation 3 ways meiosis produces genetic variation 1. Crosses over/recombination in Prophase 1 2. Random assortment in metaphase 1 3. Random fertilization - The sperm that fertilizes the egg is random Mitosis vs. Meiosis Type of Cell Division Mitosis Meiosis Importance of process Produces identical - Genetic continuity daughter cells for growth - Cell division into haploid and repair and numbers (23) maintenance - Ensures genetic continuityJenkin Tsang G11 2011-2012 Location of the process Somatic Cells Germ Cells (Ovaries and Testes) Number of cell divisions 1 2 Number of cells produced 2 4 by the process Genetic characteristic of Identical Genetically Different the daughter cell(s) produced compared to the parent cell Number of chromosomes 46 23 per Cell at the end of the process Mistakes in meiosis: nondisjunction, polyploidy (Down syndrome, Turner, etc) - When chromosomes fail to separate during meiosis, this is called nondisjunction, which leads to aneuploidy Aneuploidy: a condition where there are too many or too few chromosomes Down Syndrome: Uneven division of chromosome 21, one gamete ends up with 3 copies of chromosome 21 (Trisomy 21) - Down Syndrome is an example of a condition known as polysomy: possession of an extra copy of a chromosome • Triple X Syndrome: females with an extra X chromosome • Kleinfelter Syndrome: males with an extra X chromosomes (XXY) - Monosomy is the possession of only one copy of a pair of homologous chromosomes • Turner Syndrome: Females who are missing one sex chromosome (XO) More on the mistakes… Polyploidy – nondisjunction of all chromosomes • Triploids have 3 copies of each chromosome (3n) • Tetraploids have 4 copies of each chromosome (4n) Since diploids parents cannot produce fertile offspring with Tetraploids, they are considered different species (Sympatric Speciation) **Mistakes happen during Prophase 1 of meiosis, during the recombination process Sexual vs. Asexual ReproductionJenkin Tsang G11 2011-2012 Mendelian Genetics Dominance, recessive, hybrid, P and F generations Genotype and phenotype Genotype is the genetic make up Phenotype is the physical appearance Genotype determines phenotype Homozygous, heterozygous Homozygous: having identical alleles for a single trait Heterozygous: having different alleles for a single trait Law of Segregation Members of a pair of alleles for a given trait are segregated when gametes form Law of Independent Assortment Segregation for different pairs of alleles occurs independently Monohybrid and dihybrid Dihybrid: heterozygous for alleles of two different genes Monohybrid: a hybrid produced by 2 parents that are homozygous for 1 gene (one parent is AA, the other is aa) Punnet Squares/ Test Crosses Test Cross – the cross of an individual whose genotype is being tested, to be a homozygous recessive individual Post Mendelian Genetics Incomplete Dominance E.g. White Cow + Red Cow = Pink Cow Co-dominance E.g. White Cow + Red Cow = White cow with red spots Blood Types: multiple alleles 3 blood alleles: A, B, OJenkin Tsang G11 2011-2012 Blood Type Possibly Genotypes A I I , I I B O B IA BII AB I I O I IO The “Rh” factor also determines the blood type (Rh+ is dominant over Rh-) Genes, Chromosomes, and DNA Karyotype Composed of 7 groups of chromosomes (A-G) plus the sex chromosomes (X and Y) Chromosomes are grouped according to size, position of the centromere, and banding patterns First seven groups are called autosomes X and Y are called sex chromosomes Sex determination (XX or XY) Y chromosome is much shorter than X XX = Female XY= Male Sex linkage: X-linked disorders (haemophilia, color blindness) Refer to “Meiosis” Genetic Disorders Types of Mutations Deletion – Segment of chromosome is lost, can lead to disease or abnormality Duplication – Segment of chromosome is duplicated on the same chromosome Fission – Chromosome piece breaks apart, forming two shorter chromosomes Fusion – Two different chromosomes are joined Inversion (Paracentric) – Segment of chromosome is turned upside down (does not include the Centromere) Inversion (Pericentric) – Segment containing Centromere and both arms of a chromosome is turned upside down Translocation (Reciprocal) – 2 chromosomes trade pieces with one another Pedigrees Square = male Circle = female Colored in = has the disorder of interest Jenkin Tsang G11 2011-2012 Typical Autosomal (Somatic) Disorder - Tends to skip a generation - Equal distribution between males and females The parent generation are not considered to be part of the “generations” in the pedigree Evolution Overview Charles Darwin and his Observations 1. Species vary globally • Noted that related species living in similar habitats in different parts of the world looks and acted similarly • Noted plants and animals of South America were distinct from species in Europe or Africa 2. Species vary locally Jenkin Tsang G11 2011-2012 • Noted related species that lived in different habitats within a local environment had different features o Most obvious on islands o In Galapagos, noted that island organisms were similar to, but different from the plants and animals of the nearest mainland o Noted that remote islands were inhabited by birds and other flying organisms, and land animals (i.e. lizards and turtles) that could survive long periods at sea with no food or water o Not many mammals 3. Species vary over time • Observed fossils of extinct animals that looked very similar to living animals o Saw an earthquake occur and saw a piece of land (originally underwater) rise 3m up in the air and then he began to understand how shelled animals got on top of mountains 4. Breeding • Observed that there is variation within populations and that some of these variations can be inherited Development of Evolutionary Theory Who When What Georges-Louis 1707-1788 - Buffon was the first to suggest similarities between humans and apes and even talked about common Leclerc, Comte de ancestry of Man and apes. He was the first to Buffon openly suggest that the planet was much older than the 6,000 years proclaimed by the church, and discussed concepts very similar to Charles Lyell's "uniformitarianism" which were formulated 40 years later. Thomas Malthus 1766-1834 - Come up with natural selection - He believed that populations cannot get big because population growth will outgrow food supply Jenkin Tsang G11 2011-2012 growth. And that disease and famine kept populations in check. Georges Cuvier 1769-1832 - He was the first to declare that species can go instinct - Catastrophism=the doctrine that certain vast geolog ical changes in the earth'shistory were caused by catastrophes rather than gradual evolutionary processes Jean Baptise - Declared that traits can be inherited - A change in the environment causes changes in the Lamarck needs of organisms living in that environment, which in turn causes changes in their behavior. - Declared evolution Charles Lyell & Mid-late Fathers of uniformitarianismgeology James Hutton 1700`s - Hutton stated that the Earth was transformed not by unimaginable catastrophes but by imperceptibly slow changes - Lyell saw evidence of Earth’s history (geologic time) by studying various types rocks around the world - Uniformitarianism states that the processes that alter the Earth are uniform and gradual through time. - Influence of Darwin`s theory of Evolution Alfred Russel 1823-1913 - One of the first people to declare a theory to support evolution, it was the same theory as Wallace Darwin’s, Darwin just beat him to publishing it T.H. Morgan 1866 –1945 - He was a geneticist and experimented with fruit flies - He discovered that chromosomes can be passed on and they can also mutate Stephen Jay 1941- 2002 - His theory of “Punctuated equilibrium” contradicts Gould Darwin’s theory that evolution is a slow, gradual process with no sudden change. - This theory (based on fossil studies) stated that there are period in time where nothing changes and sudden periods in time where lots changes. Natural Selection • “How” Evolution happens • In order for natural selection to occur, VISTA is needed o Variation – Differences among members of the same species, must be able to be inherited o All species tend to produce more offspring than can survive o Selective Pressure – Environmental conditions (food, water, space, climate, etc) that select individuals best suited for those conditio
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