Zoology 100 Notes 4

ZOOLOGY 100 NOTES (4) CHEMICAL BASIS OF LIFE THE PROTOPLASM IMPORTANT FACTS: • 25 chemical elements = essential to life • Atomic structure determines the behavior of an element. • Interaction among atoms (how atoms bond to form molecules) is the basis of biological structure and function. - Each kind of atom has a characteristic number of protons, neutrons, and electrons. - An atom's behavior (how it interacts with other atoms) is determined by the arrangement of its electrons. *body functions depend on cellular functions. - cellular functions result from chemical changes * biochemistry helps to explain physiological processes, and develop new drugs and methods for treating diseases NATURE OF MATTER A. ATOMIC STRUCTURE FACT: the universe is composed of 103+ elements, each with unique atomic structure ATOM – the smallest unit of matter that cannot be broken down by chemical means - components: protons,neutrons and electrons ATOM STRUCTURE

B. MOLECULES – smallest particle of an element; - formed by 2 or more atoms bonded together COMPOUNDS – 2 or more different types of atoms bonded together C. TYPES OF BONDS 1. IONIC BONDS 2. COVALENT BONDS 3. HYDROGEN BONDS PROTOPLASM  The living part of the cell: organic and inorganic compounds  The primary living substance; the true nature & as the material basis for vital phenomena (by French naturalist F. Dujardin, 1835)  In 1861, vegetable sarcode & animal protoplasm was proclaimed by Max Schultze (framer & founder of the modern notion of the protoplasm)  In eukaryotes: - cytoplasm: protoplasm surrounding the nucleus - the semi fluid protoplasm (colloid/hyaloplasm) - nucleuplasm: protoplasm inside the nucleus In prokaryotes: - bacterial cytoplasm: material inside the plasma membrane - periplasm: region outside the plasma membrane but inside the outer membrane

 Origin: Gk. Protos (first), & plasma (thing formed)

- Thomas Huxley: “physical basis of life”  Properties: 1. Physical – colloidal system - sol –> gel reversals 2. Chemical – organic and inorganic compounds 3. Biological - reproduction,metabolism, irritability, adaptability Inorganic Substances Water (H2O): 55-90% of the protoplasm • most abundant compound in living material - two-thirds of the weight of an adult human - major component of all body fluids • medium for most metabolic reactions - important role in transporting chemicals in the body - absorbs and transports heat Oxygen (O2): • used by organelles to release energy from nutrients in order to drive cell’s metabolic activities - necessary for survival Carbon dioxide (CO2): • waste product released during metabolic reactions - must be removed from the body • carried through 3 ways: 5% in sol’n. In plasma = carbonic acid 10% in combt’n. w/ amino grps. Of hemoglobin 85% as sodium & potassium bicarbonates (blood salts) in plasma & RBC Inorganic salts • abundant in body fluids • sources of necessary ions (Na+, Cl-, K+, Ca2+, etc.) • play important roles in metabolism • hard bulk deposits: bone, teeth or shells Organic Substances Carbohydrates • provide energy to cells • supply materials to build cell structures • water-soluble • contain C, H, and O • ratio of H to O close to 2:1 (C6H12O6) FORMS: • monosaccharides – glucose, fructose, galactose, pentoses • disaccharides – sucrose (glucose+ fructose), - lactose (glucose+galactose), maltose (2 glucose • polysaccharides – glycogen, cellulose, starch

LIPIDS

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soluble in organic solvents; insoluble in water fats (triglycerides) • used primarily for energy; most common lipid in the body • contain C, H, and O but less O than carbohydrates (C57H110O6) • building blocks are 1 glycerol and 3 fatty acids per molecule • saturated and unsaturated phospholipids • building blocks are 1 glycerol, 2 fatty acids, and 1 phosphate per molecule • hydrophilic and hydrophobic • major component of cell membranes

steroids • four connected rings of carbon • widely distributed in the body, w/ various functions • component of cell membrane • used to synthesize hormones Cholesterol

PROTEINS • C, H, O, N • structural material • energy source • hormones • receptors • enzymes • antibodies • amino acids held together with peptide bonds FORMS:

1. simple: a. Soluble: albumen b. Insoluble: keratin, globulins 2. conjugated: non-protein in nature; a. Nucleoproteins b. Chromoproteins: hemoglobin, hemocyanin c. Glycoprotiens: mucin, mucoid (connective tissue) d. Lecithoprotien: egg yolk e. Phosphoproteins: casein (milk), ovovitellin (egg yolk) 3. Derived proteins: peptones, proteoses, polypeptides 4. Regulatory proteins: a. Enzymes: ptyalin (carbohydrate - maltose) b. Hormones: i) insulin ii) testosterone & progesterone c. Vitamins d. Respiratory pigment: HEMOGLOBIN (hematin: red)

NUCLEIC ACIDS • carry genes • encode amino acid sequences of proteins • building blocks are nucleotides

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DNA (deoxyribonucleic acid) – double polynucleotide RNA (ribonucleic acid) – single polynucleotide

RNA

CLINICAL APPLICATION CT Scanning and PET Imaging • techniques used to give anatomical and physiological information, respectively • CT scanning uses X-ray emissions to provide 3-D image of internal body parts • PET imaging used radioactive isotopes to detect biochemical activity in a specific body part MRI produces pictures of various parts of your body without the use of x-rays (unlike regular x-rays pictures & CT scans) and without the use of nuclear element injection like gallium scans. MRI scanner consists: of large and very strong magnet in which the patient lies, a radio wave antenna is used to send signals* to the body and then receive signals back. -The returning signals are converted into pictures by a computer attached to the scanner. -Pictures of almost any part of your body can be obtained at almost any particular angle. (* These "radio wave signals" are actually a varying or changing magnetic field that is much weaker than the steady,