BIO 1120 Unit 2 Study Guide
BIO 1120 Unit 2 Study Guide bios 1120
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This 9 page Study Guide was uploaded by Perry Klemanski on Wednesday February 17, 2016. The Study Guide belongs to bios 1120 at Western Michigan University taught by David Rudge in Winter 2016. Since its upload, it has received 28 views. For similar materials see Principles of Biology in Biological Sciences at Western Michigan University.
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Date Created: 02/17/16
Unit Two Study Guide Chapter 9 9.1 Cells divide to replace cells and perpetuate the species - Cell division involves the transmission of hereditary information contained in DNA to daughter cells - Cell division is the basis for both asexual and sexual reproduction 9.2 The prokaryotic cell cycle is very simple - The DNA of prokaryotes consists of a single, circular chromosome - The replicated DNA attaches to the plasma membrane - Cell division occurs by means of prokaryotic fission 9.3 Eukaryotic chromosomes are organized differently - Multiple chromosomes are contained within the nucleus - Usually exist as non-identical pairs of linear DNA double helices bound to proteins (diploid = 2 versions of each chromosome) - Not all cells are diploid; haploid cells containing one member of each pair (gametes) play role in sexual reproduction 9.4 The eukaryotic cell cycle consists of interphase and mitosis - Interphase: Period of growth, differentiation and replication of DNA - Mitotic Cell division: involves mitosis and cytokinesis 9.5 Mitotic cell division leads to creation of identical daughter cells - Prophase: Chromosomes condense and spindle fibers form - Metaphase: Chromosomes line up along cell equator - Anaphase: Sister chromatids representing same chromosome split - Telophase: Chromatids reach poles, nuclear envelope reforms - Cytokinesis: cytoplasm divides between sister cells 9.6 The cell cycle is controlled by multiple mechanisms - Hormones (growth factors) stimulate cell division by controlling the synthesis of proteins (cyclins); checkpoints also regulate the process 9.7 Sexual reproduction produces genetically unique offspring - Occurs by means of shuffling genes contained in parents, mutations 9.8 Meiosis leads to the production of haploid cells (gametes) - The fusion of haploid gametes (fertilization) restores the diploid - Meiosis is divided into two stages - Meiosis I: separates homologous chromosomes, sending one homologue into each of two haploid daughter cells - Meiosis II: Separate identical chromatids from one another, creating four haploid daughter cells 9.9 Mitotic and Meiotic cell division occur at different stages -Life cycle of eukaryotic organisms begins with fertilization (union of haploid gametes); resulting diploid zygote undergoes mitotic cell division and subsequent differentiation - Reproduction of new individuals may involve haploid cells - Eukaryotic organisms differ in how much of their life cycle is spent primarily a diploid (animals) and haploid (fungi), many plant species alternate between the two 9.10 Genetic variability is the result of the shuffling of homologues, crossing over, and the fusion of gametes Chapter 10 10.1 The physical basis of inheritance is the process by which information coding for traits (genes) is passed from parent to offspring - Genes are located at particular locations (loci) on chromosomes - Different forms of genes (alleles) differ in how the code traits - Offspring inherit two alleles, one from each parent - If these alleles are identical, the offspring of homozygous - If these alleles differ, the offspring is heterozygous 10.2 Gregor Mendel discovered the principles of inheritance - Chose right organism, designed appropriate experiment, analyzed results properly - Worked with the edible pea that self-fertilizes - Mated different pea plants by means of cross fertilization 10.3 Mendel first worked on single traits - True breeding organisms always give rise to offspring that look like parents - Crossing true breeding organisms that have different versions of the trait allows one to determine which allele is dominant and which is recessive (dominant alleles mask the presence of the recessive allele) - Law of segregation: each individual has two copies of a gene (one from each parent), and the gametes that individual creates contain only one copy - Genotype: which two alleles the individual has - Phenotype: What the individual looks like - Punnett Square Method: way to keep track of genotypes and resulting phenotypes of offspring that can be used to predict outcomes of crosses 10.4 Mendel then considered how multiple traits are inherited - Law of independent assortment: when considering multiple traits, the allele that the offspring receives from its parents for one trait is inherited independently from the allele that the offspring will receive from that parent for other traits - The significance of Mendel’s research was not recognized until decades later 10.5 Mendelian rules do not apply to all traits - Incomplete dominance: The presence of one allele may not completely hide the presence of the other - A single trait may have multiple alleles - Codominance: the presence of both alleles is expressed - Polygenetic inheritance: many traits are results of many genes - Pleiotropy: A single gene may influence more than one trait - The environment may also influence the expression of genes 10.6 Gene linkage: genes on same chromosome tend to be inherited together - But crossing over between sister chromosomes during meiosis can lead to the exchange of material (genetic recombination) - The greater the distance between genes on the chromosome, the greater chance of crossing over 10.7 Sex and sex-linked traits have different patterns of inheritance -The sex of an offspring is determined by the sex chromosome inherited from the male parent (XX=female, XY=Male) 10.8 Human genetic disorders are inherited by means of a variety of mechanisms - Including single genes, and inheritance of abnormal number of chromosomes Chapter 11 11.1 Scientists discovered genes are made of DNA by series of elegant investigations - Griffith established that something contained in a dead disease causing strain of bacteria could be transferred to a weakened strain - Avery, Macleod and McCarty discovered the transformative agent is DNA 11.2 The structure of DNA allows it to encode genetic info - DNA consists of long chains of subunits (nucleotides) - Nucleotides consists of a sugar, a phosphate and a base - There are only four bases in DNA (Adenine, Thymine, Guanine, and Cytosine) - Chargaff discovered that regardless of the species, the amount of A = T, and the amount of G = C - Watson and Crick determined DNA is a double helix of two nucleotide strands held together by hydrogen bonds 11.3 Genetic information is encoded by the sequence of bases 11.4 The replication of DNA ensures genetic constancy -The process of DNA replication involves the separation o the two strands by DNA helicases and the formation of two new strands using the original strands as templates - Semiconservative replication: DNA replication conserves each of the parental strands 11.5 Mutations occur as a result of errors in replication -While the process of DNA replication includes proof reading mechanisms, it is not entirely perfect - Changes may include nucleotide substitutions, point mutations, insertion mutations and deletion mutations Chapter 31 31.1 Animals must regulate their internal environments owing to internal and external changes - The external environment may change - The internal environment may change - Homeostasis – refers to the ability of an organism to maintain its internal environment despite these changes - Feedback mechanisms regulate internal conditions -Positive feedback mechanism: exacerbates change - Negative feedback mechanism: returns system back to normal - All feedback mechanisms involve a sensor, a control center and an effector 31.2 The animal body is composed of cells, tissues, organs, and organ systems - Cells are the basic units of life - Tissues are composed of cells similar in structure and function - Epithelial tissues: sheets of cells that line body cavities, glands - Connective tissues: Tissues that include extracellular matrix – tendons, bone, blood - Muscle tissue: tissues with the ability to contract – skeletal, smooth and cardiac - Nerve tissue: tissues that can transmit electrical signals – brain, neurons - Organs are two or more interacting tissues - Organ systems are two or more interacting organs Chapter 41 41.1 Animals reproduce both asexually and sexually - Asexual reproduction results in clones - Sexual reproduction involves union of sperm and egg - May involve one individual, but usually two - External fertilization: Union of egg and sperm is external, with sperm and egg being deposited in water by means of spawning - Internal fertilization: union of egg and sperm is within the body to female 41.2 Human reproductive systems play roles in both reproduction and health of organisms - Puberty: age at which individual becomes capable of reproducing - In both sexes, begins in hypothalamus with release of GnRH, which stimulates the pituitary to produce LH and FSH - In males, sperm are produced by means of spermatogenesis - In females, eggs are produced by means of oogenesis 41.3 Pregnancies can be prevented by a variety of means - Sterilization - Temporary birth control - Prevent ovulation - Prevent fertilization - Prevent implantation - Some methods of birth control are not effective against STD’s - The only complete protection against pregnancy is abstinence Chapter 43 43.1 Plant bodies, like animal bodies, are composed of cells, tissues, organs and organ systems - Root System: under the ground, serves to: anchor plant; absorb water and minerals; transport water, minerals and hormones; stores surplus sugars and starches; and interacts with soil fungi and bacteria that help plant acquire nutrients - Shoot System: above ground, serves to: capture sunlight energy; synthesize sugars during photosynthesis; transports materials to all parts of plant; stores surplus sugars and starches; reproduce; and produce hormones - The plant kingdom is divided into monocots and dicots - Monocots: single cotyledon; Dicots: two cotyledons 43.2 Plants undergo both primary and secondary growth 43.3 Plants are composed of multiple tissue types - The dermal tissue system covers the plant body, protects it from pathogens and prevents the loss of moisture - The vascular tissue system is composed of xylem and phloem - The ground tissue represents all other tissues of the plant body, including tissues used for storage, photosynthesis and the secretion of hormones 43.4 Leaves play a primary role in photosynthesis and the exchange of gases with the atmosphere 43.5 Stems are composed primarily of vascular tissue and are the site of primary and secondary growth and the support of other structures 43.6 Roots transport minerals and water from the soil 43.7 Plants need only inorganic nutrients, trace minerals from the soil - Trace minerals are absorbed from soil water into a living cell by active transport against a concentration gradient - These minerals are the transported into interconnected living cells by means of plasmodesmata - Minerals then exit the living cells by means of active transport or diffusion into the xylem 43.8 The flow of water in xylem within the body of the plant is due to the cohesion-tension mechanism - Transpiration is the basic driving force for movement - According to the cohesion-tension mechanism, water is pulled up as a result of two processes: cohesion between water molecules owing to hydrogen bonding and tension produced by the evaporation of water from the leaves - Guard cells responsible for opening and closing the stomata regulate the escape of both water vapor and gas exchange 43.9 The transport of sugars in the plant occurs via the pressure- flow mechanism - Differences in water pressure, owing to the creation of sugars in sources are the basic driving force for movement of materials towards sinks Chapter 44 44.1 Plants reproduce both asexually and sexually -Alternation of generations describes the sexual reproductive cycle of plants because they alternate between multicellular diploid (sporophyte) and multicellular haploid (gametophyte) generations 44.2 Angiosperms have flowers that typically contain both male (stamen) and female (carpel) reproductive structures -Flowers represent a mechanism by which flowers attract animal’s pollination - Pollination is the process by which the male spore is transferred from the male reproductive organ of one flower to the female organ of another flower - Successful pollination results in the release of a sperm that fertilizes an egg produced by the female spore - The gametophyte in most familiar plant species is microscopic and exits within the female reproductive organ 44.3 Fruits develop from the ovary; seeds from the ovule -The fruit is a means by which plants entice animals to distribute their seeds away from the parental plant -The seed contains stored energy for use by the developing embryo. It initially protects the embryo 44.3 Seeds germinate after a period of dormancy, often involving cold and drying 44.4 Plants attract pollinators by means of a variety of mechanisms, including color, smell and food 44.5 Fruits aid plants in the dispersal of seeds - Some fruits directly disperse seeds - Other fruits indirectly disperse seeds by attaching to animals; or in the case of edible fruits enticing them to carry the seeds away how many haploid cells are produced by one diploid cell during meiosis 4
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