BIOL 425 1st EditionExam # 1 Study Guide Lectures: 1 - 8Chapter 1 (Botany: An Introduction)Concept: How did organisms adapt to conquer land?The first organisms were heterotrophs, meaning that they satisfy their energy requirements by consuming organic compounds produced by external sources. As these primitive heterotrophs increased in number, resources became scarce and competition developed. This required that cells make efficient use of their limited energy sources. Over time,autotrophic (“self-feeding”) cells evolved such that they could produce their own energy-rich molecules out of simple inorganic materials. This evolution was necessary for the continuation of life on Earth.The most successful autotrophs were photosynthetic meaning that they developed a system for making direct uses of the sun’s energy. The development of photosynthesis led to theflow of radiant energy from the sun being channeled through the photosynthetic autotrophs to all other life forms (the same as it is today). Photosynthesis also altered the earth’s atmosphere by splitting a water molecule and, consequently, releasing oxygen as free oxygen molecules (O2)which eventually accumulated in the atmosphere. Some of the oxygen was then converted into ozone (O3) which helps to protect against harmful UV rays. This adaptation allowed for the possibility of life on land.The availability of free oxygen enabled organisms to break down these molecules through respiration. This process utilizes oxygen and yields significantly more energy than anaerobic processes. Prior to the accumulation of oxygen in the atmosphere, only prokaryotic cells existed. This meant that the only cells were ones that lacked a nuclear envelope and did not have their genetic material organized into complex chromosomes. The increase in free oxygen brought on the appearance of eukaryotic cells (cells with nuclear envelopes, complex chromosomes and organelles).Concept: Basic plant anatomy- Organs:o Roots – anchor the plant in the ground and collect water required for maintenance of the plant body and for photosynthesiso Stems – provide support for the leaveso Leaves – the principal photosynthetic organs- Epidermis – outermost layer of cells- Cuticle – waxy substance that coats the aboveground portion of the plant and retards water and prevents exchange of gases between plant and surrounding air- Stomata – consists of a pair of specialized epidermal cells with a small opening between them which opens/closes in response to environmental and physiological signals. This helps the plant to maintain a balance between water losses and oxygen/carbon dioxide requirements.- Vascular system – conducts a variety of substances between the photosynthetic and non-photosynthetic parts of the plant body. Two major components:o Xylem – through which water passes upward through the plant bodyo Phloem – through which food manufactured in the leaves and other photosynthetic parts of the plant is transported throughout the plant body- Meristems – origin of plant growth, composed of embryonic tissue regions capable of adding cells indefinitely to the plant bodyo Primary growth – growth that originates from apical meristems (extension of the plant body)o Secondary growth – growth that results in the thickening of roots and stems (originates from two lateral meristems)- Seeds – composed of the plant embryo, supply of stored food and seed coat (protects embryo from drought and predators)Concept: Greenhouse effectIt is estimated that by 2050 the average temperature will have increased about 2.5 degrees Celsius. This “global warming” phenomenon is brought on by the trapping of heat radiating from Earth’s surface out into space. This process is intensified through the increased amounts of carbon dioxide, nitrogen oxides, chlorofluorocarbons and methane in the atmosphere resulting from human activities. This has resulted in an overall decreases in biodiversity on Earth.Chapter 2 (The Molecular Composition of Plant Cells)Concept: Plant chemistry- Organic molecules:o Carbohydrates – consisting of sugars and chains of sugarso Lipids – contain fatty acidso Proteins – composed of amino acidso Nucleic acids – DNA and RNA, made up of complex nucleotides- Carbohydrates:o Sugars – the simplest carbohydrates (larger carbohydrates are composed of sugars joined together)o Monosaccharides – simple sugars such as ribose glucose and fructose, consisting of only one sugar molecule (Function as building blocks and sources of energy)o Disaccharides – contain two sugar subunits linked covalently (ex. sucrose maltose and lactose) (Transport form of sugar in plants)o Polysaccharides – contain many sugar subunits linked together (ex. cellulose and starch) (Function as storage forms of energy or as structural materials)- Proteins:o All proteins are polymers of nitrogen-containing molecules called amino acids, arranged in a linear sequence. Thus, amino acids are the building blocks of proteins.- Polymers – macromolecules that are made up of similar or identical small subunits- Monomers – the individual subunits of polymers (polymerization is the stepwise linking of monomers into polymers)- Hydrolysis – Occurs when a disaccharide is used as an energy source and is split into its monosaccharide subunits, a molecule of water is addedConcept: Fats and oils- Lipids – fats and fatlike substances, generally hydrophobic (“water-fearing”), serve asenergy-storage molecules (usually in the form of fats or oilso Fats and oils – have similar chemical structures, each consists of three fatty acid molecules bonded to one glycerol molecule. These bonds are formed by dehydration synthesis (a condensation reaction). Fat and oil molecules are also called triglycerides and contain no polar groups, making them insoluble in water. A fatty acid that had no double bonds between carbon atoms is saturated.o Sterol – a steroid with a hydroxyl group at the carbon-3 position (ex. cholesterol)o Phospholipids - composed of fatty acid molecules attached to a glycerol backbone, play important structural roles in cellular membranes.- Secondary metabolites:o Restricted within their distribution, both within the plant and among the different species of plants (not found in all plant cells like primary metabolitesare)o Alkaloids – alkaline nitrogenous compounds that include morphine, cocaine caffeine, nicotine and atropineo Terpenoids – composed of