APHY 101 Final Exam - Questions and Answers What are the characteristics of DNA? Double-stranded DNA molecules twist to form a double helix consisting
... [Show More] of "sugar-phosphate rails" and bases pair to form the "rungs." What are the 4 types the DNA molecule base can be? (A) adenine (T) thymine (C) cytosine (G) guanine What are the complementary base pairs for DNA? A T C G Ribonucleic Acid (RNA) Single-stranded molecules, their nucleotides have ribose rather than deoxyribose sugar, and uracil rather than thymine. Functions in protein synthesis. Nucleotides Building blocks of nucleic acid; consist of a 5-carbon sugar, a phosphate group, and one of several nitrogenous bases What are the 4 types the RNA molecule base can be? A) adenine (T) uracil (C) cytosine (G) guanine How is RNA made? All of the RNA in a cell is made by DNA transcription, a process catalyzed by a class of enzymes called RNA polymerases. List the steps of protein synthesis. During protein synthesis tRNA molecules bring the appropriate amino acids to align against an mRNA molecule temporarily held on a ribosome. The aligned amino acids join and the polypeptide that grows folds. Transcription the process of copying the information encoded in DNA to produce RNA Translation The process of translating the series of codons of mRNA from the language of nucleic acids to the language of amino acids. Codons set of three nucleotides in a messenger RNA molecule corresponding to one of the 20 types of amino acids How does DNA replicate? During interphase, hydrogen bonds break between the base pairs. The strands unwind and part, and free nucleotides come in and hydrogen bonds form between the new and the old. Enzymes catalyze the base pair bonding and the knitting together of the sugar-phosphate backbone. Mutations The rare distinctions in DNA sequence that affect how we look or feel. Mutations may be spontaneous (due to transient mispairing during DNA replication) or induced by exposure to certain chemicals or radiation. What is a tissue? layers or groups of similar cells with a common function What are the four types of tissues in the body? Epithelial, connective, muscle, and nervous tissues What are the general characteristics of epithelial tissue? Covers body surface and organs, lines body cavities and hollow organs, composes glands, lacks blood vessels, cells readily divide, and cells are tightly packed; they function in protection, secretion, absorption, excretion, and sensory reception. How are most epithelial tissues named? Epithelial tissues are classified according to cell shape and number of cell layers What is glandular epithelium? a single cell or a mass of cells; produces and secretes substances into ducts or into body fluids Simple Squamous Epithelium single layer of thin, flattened cells; it functions in the exchange of gases in the lungs and lines blood and lymph vessels as well as body cavities Simple Cuboidal Epithelium single layer of cube-shaped cells with centrally located nuclei; it functions in secretion and absorption in the kidneys, and in secretion in glands Simple Columnar Epithelium a row of elongated cells whose nuclei are all located near the basement membrane; it lines the uterus, stomach, and intestines where it protects underlying tissues, secretes digestive fluids, and absorbs nutrients Pseudostratified Columnar Epithelium These cells appear layered due to the varying positions of their nuclei within the row of cells, but are not truly layered; in the female reproductive tract, cilia on these cells aid in moving eggs through the oviducts to the uterus Stratified Squamous Epithelium layers of flattened cells that are designed to protect underlying layers; it makes up the outer layer of skin, and lines the mouth, throat, vagina, and anal canal. Stratified Cuboidal Epithelium three layers of cuboidal cells lining a lumen of the mammary glands, sweat glands, salivary glands, and pancreas Stratified Columnar Epithelium several layers of cells and is found in the vas deferens, part of the male urethra, and parts of the pharynx Transitional Epithelium designed to distend and return to its normal size, as it does in the lining of the urinary bladder What are the general characteristics of connective tissue? Cell types? Fiber types? Bind, support protect, fill spaces, store fat, produce blood cells; The fibroblast is the most common cell type, and is a large, star-shaped cell that secretes fibers and is fixed into position; Strong collagenous fibers (white fibers), made of the protein collagen, add strength for holding body parts together Adipose Tissue connective tissue designed to store fat; it is found beneath the skin, around joints, padding the kidneys and other internal organs, and in certain abdominal membranes Dense Connective Tissue Densely packed collagenous fibers; very strong but lacks a good blood supply; found as part of tendons and ligaments. [Show Less]