BIOS 242 MIDTERM EXAM QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED GRADE A++

BIOS 242 MIDTERM EXAM QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED GRADE A++ Practice questions for this set Terms in this set (63) Louis Pasteur disproved spontaneous generation with swan neck flasks and pasteurization Koch's Postulates Set of rules for proving that a microorganism causes a specific disease. Helped invent inoculation, isolation, media, maintenance of pure cultures, prep of specimens for microscopic examination. He identified the specific causative agents of tuberculosis, cholera, and anthrax. Leeuwenhoek First simple microscope (300x) and father of bacteriology and protozoology. Parasite An organism that lives on or in a host and causes harm to the host Inoculation The process of cultivating. Introduces sample into nutrient medium. Generation time the time it takes for a population to double in binary fission Prions Infectious protein particles that do not have a genome. Results in spongiform encephalopathies. Sterilization The process that completely destroys all microbial life, including spores. Uses dry heat and ionizing radiation. Disinfection Destroys most microbial life, reducing contamination on inanimate surfaces. Uses moist heat and nonionizing radiation. Endotoxin Present in gram negative bacteria and sheds from the outer membrane or released during lysis. Causes fever and inflammation. Toxic in high doses. Fomite inanimate object that harbors and transmits pathogens (doorknobs, toys, toilet seats, and phones). Classify viruses Viruses are classified by the type of nucleic acid used as the genetic material. The viral genome may be composed of single-stranded DNA, double-stranded DNA, single-stranded RNA, or double stranded RNA, sense and method of replication. Naked Virus Structures Spike, Nucleic acid, and capsid Enveloped Virus Structures Spike, nucleic acid, capsid, and envelope How are viroids transmitted? Between plants in the same manner as viruses (leaf contact and plant seeds). Where most pathogens enter the body? Portal of entry (skin, GI tract, respiratory tract, urogenital tract, and endogenous biota). First step of gene expression Transcription: the process of copying a segment of DNA into RNA Second step of gene expression Translation: the synthesis of protein form RNA. Has three stages: initiation, elongation, and termination. Structures in gene expression Frameshift Mutation one or more bases are inserted into or deleted from a newly synthesized DNA strand Point Mutation addition, deletion, or substitution of single bases Missense Mutation Any change in the code that leads to placement of a different amino acid Nonsense mutation changes a normal codon into a stop codon that does not code for an amino acid and stops the production of the protein wherever it occurs. A nonsense mutation almost always results in a nonfunctional protein.