Bacterial Cell Structure and Function, Exams of Microbiology

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BIO 2104 Exam 2 Questions and Complete Solutions Graded A+ [Document subtitle] Denning [Date] [Course title]

List and describe three structures common to all bacteria - Answer: Cell wall, Flagella, Fimbriae, Pilus (Many other examples available)Cell membrane, DNA chromosome, Ribosomes List and describe four structures found in some bacteria - Answer: Cell wall, Flagella, Fimbriae, Pilus (Many other examples available) What are the three general shapes of bacteria - Answer: Cocci, Bacilli, Vibrio Describe two arrangements found among the general shapes of bacteria - Answer: Staphylo- Strepto- diplo- or tetrad True/False: Bacterial fimbriae are used for conjugation - Answer: False Describe the differences between capsules and biofilms - Answer: Capsules are a protective outer layer surrounding a singular organism Biofilms are a protective outer layer made to surround and protect a diverse group of organisms Pili - Answer: Attachment from one gram-negative bacterial cell to another for conjugation (bacterial sex) to transfer plasmids. Plasmids are small pieces of DNA with extra traits like antibiotic resistance Fimbriae - Answer: Fuzzy, small appendage that surrounds the bacterial cell and allows for attachment to surfaces Flagella - Answer: Long, tail-like appendage(s) that allow for true motility and, in some cases, attachment You successfully complete gram staining and your bacteria are all pink/red. What is your gram stainingresult? What does it tell you about the structure of this bacterial species? - Answer: Gram Negative Organism (Pink/Red) The bacteria have a thin peptidoglycan layer in their cell wall and an inner and outer membrane Gram Positive - Answer: Thick peptidoglycan layer which stains purple. Only an inner cell membrane. Usually easier to treat due to the thick peptidoglycan layer being easily targeted by antibiotics.

Sporulation - Answer: Vegetative cell becoming an endospore Do bacterial cells have a nucleus? If not, what do they have? - Answer: No, they have no organelles. Instead they have a nucleoid region Describe bacterial DNA. Is it circular or linear? - Answer: Bacterial DNA is circular and double stranded. Extremophile - Answer: Extreme-loving Methanogen - Answer: Methane producer Halophile - Answer: Salt-loving Psychrophile - Answer: Cold-loving Hyperthermophile - Answer: Extreme heat-loving True/False: Archaea do not cause human disease. - Answer: False True/False: Eukaryotes and prokaryotes evolved independently. - Answer: False __________ evolved from primitive cells that became trapped in larger cells. - Answer: Mitochondria/Chloroplasts List four types of eukaryotes studied by microbiologists. - Answer: Helminths/Protozoans/Fungi/Algae What is the endosymbiont theory? - Answer: :

Which Eukaryotic organisms have cell walls made of chitin or cellulose? - Answer: Fungi or algae True or False: All eukaryotic cells have a cell membrane. - Answer: True What structures are found in all eukaryotic cells? - Answer: Cell membrane, Nucleus, mitochondria, ER, Golgi, Cytoskeleton The________ endoplasmic reticulum is responsible for packaging and transport of proteins. - Answer: Rough _________ is an organelle that ships products out of and around the cell. - Answer: Golgi apparatus What is the order of protein formation starting with Transcription of DNA to RNA and ending with the Golgi apparatus secreting the protein in a vesicle. - Answer: DNA is transcribed into messenger RNA (mRNA) Proteins are synthesized on ribosomes and deposited into the RER Proteins are then transported to the Golgi apparatus to be chemically modified and packaged into vesicles They are secreted around or outside the cells Why do Mitochondria and chloroplasts contain 70S ribosomes and circular DNA? - Answer: They are prokaryotic cells that were enveloped millions of years ago (Endosymbiont theory). This is why they have prokaryotic structures. True/False: Fungal spores have a tough outer coating that allows them to survive in extreme conditions.

• Answer: False _________ are asexual spores contained in a sac-like head. - Answer: Sporangispores Which fungi produce hyphae? - Answer: Molds Which fungi produce pseudo hyphae? - Answer: Yeast

List characteristics of viruses that distinguish them from cellular life. - Answer: They are so simple they do not contain structures to reproduce. They contain no ribosomes, enzymes, hormones, or perform metabolism. Without performing any chemical reactions, they are not considered living. True/False: Viruses are alive. - Answer: False Explain why viruses can't survive outside a host cell. - Answer: They require the host cell machinery to make copies of the virus List all the structures in all viruses - Answer: DNA or RNA genome, Capsid, Spike Protein List all the structures in some viruses - Answer: Envelope and accessory proteins Why are viruses considered obligate intracellular parasites? What host cell machinery do they use? - Answer: They must be inside a cell and use host ribosomes and enzymes to make more viral DNA/RNA and capsomeres (Capsid monomers), and spike proteins What are the three viral shapes? - Answer: Icosahedral, Helical, Complex (Bacteriophage) Naked virus - Answer: -Have a capsid outer layer -Spike proteins attached on the capsid -Leave the cell by bursting out Enveloped virus - Answer: -Spike proteins embedded on the envelope -take the host membrane and wrap themselves in it -Leave the cell by budding out -Comes from Host Cell membrane True/False: Viruses can be seen with a light microscope. - Answer: False

Viral capsids are constructed from ____________ subunits. - Answer: capsomere List three unique forms or viral nucleic acid. - Answer: DNA, RNA, RNA that is reverse transcribed to DNA (HIV) DNA viruses - Answer: replicate in the nucleus RNA viruses - Answer: replicate in the cytoplasm Oncogenic - Answer: cancer causing Provirus - Answer: Virus in the Host DNA Chronic latent state - Answer: The virus is embedded in the Host DNA and waiting for reactivation (Herpes virus-cold sores) How are viruses cultivated? - Answer: Viruses must be cultivated in living cells In vivo - Answer: Cells in a living organism In vitro - Answer: Cells on a plate True/False: Viral infections are more common than bacterial infections. - Answer: True True/False: Viral mutation rates are low and viruses are easy to track in a population. - Answer: False Doctors and scientists most often rely on _______ to treat or prevent viral infections: - Answer: vaccines Why is it difficult to create antiviral treatments? - Answer: Viruses use so much host machinery how can we target the virus without killing our own cells in the process.

Why is active transport 'against the flow' or 'an extra push'? - Answer: Either going from low to high concentrations or going from high to low concentrations but faster A __________ environment has a higher concentration of solutes outside the cell than inside the cell. - Answer: Hypertonic What are the 4 environmental factors that influence microbe discussed in lecture? - Answer: Heat, Cold, Gases, and Other microbes Fastest growth and metabolism happen at the ___________ temperature range - Answer: Optimal What are cardinal temperatures - Answer: The range that includes the minimum, optimal, and maximum temperatures a microbe can grow and have metabolism What are mesophiles? - Answer: Microbes that survive at human body temperature Lost the four different oxygen requirements for microbes? - Answer: Obligate aerobe Microaerophile Facultative anaerobe Obligate anaerobe If a bacteria lives on your skin and causes no harm or benefit to you it is a ___________ relationship - Answer: commensal A helminth eats the body of the host causing pain and inflammation is it a ___________ relationship - Answer: parasitic Define doubling time (generation time). - Answer: The time it takes for one cell to become two cells. Doubling the DNA, enzymes, and cell structures and then dividing into two cells. Describe the steps of PCR. - Answer: Denaturation: Heat up DNA strands to separate them

Annealing: Cool down the DNA so the primers can bind Extension: Make a copy of the DNA Repeat! Building molecules up is _________ and breaking molecules down is _____________. Together these make up metabolism. - Answer: anabolism, catabolism, What special proteins always end in -ase and catalyze reactions so they go faster? - Answer: enzymes Can enzymes be used in disease? - Answer: Yes, enzymes can be used to cause harm. (Ex. Penicillinase breaks down penicillin) REDOX reactions occur using the enzyme ______________. - Answer: oxidoreductase True/False: Oxidation is the gain of electrons - Answer: False What is the difference between aerobic and anaerobic metabolism? - Answer: Aerobic: Requires oxygen as the final electron acceptor Anaerobic: Requires SO3- CO3- as the final electron acceptor If an organism is an obligate anaerobe what metabolic pathway could it use? - Answer: Anaerobic respiration Define Glycolysis. - Answer: Catabolizing glucose into pyruvate to release energy How many times does glucose go through the krebs cycle? - Answer: Two times. Once per pyruvate molecule Where is the most ATP made in aerobic/anaerobic respiration? - Answer: The electron transport chain