MICRO FINAL EXAM REVIEW What is spontaneous generation?: Incorrect theory that life arises from nonliving matter. Why was the swan-neck flask important?: It allowed air in but trapped microbes. What is the difference between a scientific theory and hypo

What is spontaneous generation

: Incorrect theory that life arises from nonliving matter.

Why was the swan-neck flask important

: It allowed air in but trapped microbes.

What is the difference between a scientific theory and hypothesis

: A theory is broadly supported by evidence.

What is an isomer

: Molecules with same formula but different structures.

What bond forms between amino acids

: Peptide bond.

What bond forms between nucleotides

: Phosphodiester bond.

What bond forms between monosaccharides

: Glycosidic bond.

What are micronutrients

: Nutrients required in small amounts.

What are macronutrients

: Nutrients required in large amounts.

What does amphipathic mean

: Molecule has hydrophilic and hydrophobic regions.

Why do phospholipids form bilayers

: Hydrophobic tails avoid water while hydrophilic heads interact with water.

What is cholesterol's role in membranes

: Maintains membrane fluidity.

Why is DNA more stable than RNA

: DNA is double stranded and lacks reactive hydroxyl group.

What are purines

: Adenine and guanine.

What are pyrimidines

: Cytosine, thymine, and uracil.

What bacterial arrangement forms chains

: Strepto- arrangement.

What bacterial arrangement forms grape-like clusters

: Staphylo- arrangement.

What is the purpose of bacterial flagella

: Motility.

What powers bacterial flagella

: Proton motive force.

What is swarming motility

: Coordinated movement across surfaces.

Why are capsules important in disease

: They prevent phagocytosis.

What is endotoxin chemically

: Lipid A portion of LPS.

What is the periplasmic space

: Region between Gram negative membranes.

What is the outer membrane of Gram negative bacteria composed of

: Lipopolysaccharide and phospholipids.

Why are Gram negative bacteria often more drug resistant

: Outer membrane blocks entry.

What is acid-fast staining used for

: Mycobacterium species.

Why are Mycobacterium difficult to stain

: Waxy mycolic acid wall.

What is osmosis

: Diffusion of water across selectively permeable membrane.

What happens during hypotonic conditions

: Water enters cell.

What happens during hypertonic conditions

: Water leaves cell.

What is facilitated diffusion

: Passive transport using carrier proteins.

What is the nucleoid

: Region containing bacterial chromosome.

What are plasmids

: Small circular extrachromosomal DNA molecules.

Why are plasmids important

: Often carry antibiotic resistance genes.

What is the function of the Golgi apparatus

: Modifies and packages proteins.

What is the function of lysosomes

: Intracellular digestion.

What is the function of peroxisomes

: Breakdown of toxic substances.

What is the 9+2 arrangement

: Eukaryotic cilia and flagella microtubule arrangement.

What is the difference between eukaryotic and prokaryotic flagella

: Eukaryotic flagella use microtubules while bacterial flagella use flagellin.

What is the function of chloroplasts

: Photosynthesis.

What are centrioles

: Structures involved in spindle formation.

What are microfilaments composed of

: Actin.

What are microtubules composed of

: Tubulin.

Why are viruses considered obligate intracellular parasites

: They can only replicate inside living cells.

What is uncoating

: Release of viral genome inside host.

What is viral assembly

: Formation of complete virions.

What is latency

: Dormant viral state.

What is a temperate phage

: Bacteriophage capable of lysogeny.

What is a virulent phage

: Bacteriophage only capable of lytic cycle.

Why are enveloped viruses sensitive to soaps

: Soaps disrupt lipid envelopes.

What is receptor-mediated endocytosis

: Cell engulfs virus into vesicle.

Why do plant viruses spread differently from animal viruses

: Plant cell walls limit entry.

What are cytopathic effects

: Visible changes in infected host cells.

What is ATP synthase

: Enzyme generating ATP using proton gradient.

What is chemiosmosis

: ATP production using proton gradient.

What is oxidative phosphorylation

: ATP production using ETC.

What is photophosphorylation

: ATP production during photosynthesis.

What is the citric acid cycle

: Metabolic cycle oxidizing acetyl-CoA.

What enters the citric acid cycle

: Acetyl-CoA.

What is regenerated at the end of the citric acid cycle

: Oxaloacetate.

What are reactive oxygen species

: Toxic oxygen-containing molecules.

Why are enzymes important

: They lower activation energy.

What is competitive inhibition

: Inhibitor binds active site.

What is noncompetitive inhibition

: Inhibitor binds elsewhere and changes enzyme shape.

What is feedback inhibition

: End product inhibits earlier enzyme.

What is the Calvin cycle

: Light-independent reactions of photosynthesis.

What molecule enters the Calvin cycle

: CO2.

What enzyme starts the Calvin cycle

: RuBisCO.

What is oxygenic photosynthesis

: Photosynthesis producing oxygen.

What is anoxygenic photosynthesis

: Photosynthesis without oxygen production.

Why do obligate anaerobes die in oxygen

: Lack enzymes detoxifying ROS.

What is superoxide dismutase

: Enzyme converting superoxide radicals to peroxide.

What does catalase do

: Converts hydrogen peroxide to water and oxygen.

What is a psychrotroph

: Organism able to grow at refrigerator temperatures.

Why is refrigeration effective

: Slows microbial metabolism.

What is a fastidious organism

: Organism requiring many growth factors.

What is a chemoheterotroph

: Uses organic chemicals for energy and carbon.

What is a photoautotroph

: Uses light for energy and CO2 for carbon.

Why are mesophiles important medically

: Most pathogens are mesophiles.

What is a promoter

: DNA sequence where transcription begins.

What is RNA polymerase

: Enzyme synthesizing RNA.

What is mRNA processing

: Modification of eukaryotic mRNA before translation.

What are introns

: Noncoding sequences removed from mRNA.

What are exons

: Coding sequences remaining in mature mRNA.

What is the wobble position

: Third codon base often less specific.

What is degeneracy of the genetic code

: Multiple codons can code for same amino acid.

What is peptidyl transferase

: Enzyme forming peptide bonds.

What is a ribozyme

: RNA molecule with catalytic activity.

What is a repressible operon

: Operon normally on but turned off by repressor.

What is an inducible operon

: Operon normally off but activated when inducer present.

When is the lac operon active

: When lactose is present and glucose is low.

When is the trp operon inactive

: When tryptophan is abundant.

What is vertical gene transfer

: DNA passed from parent to offspring.

What is generalized transduction

: Random bacterial DNA transferred by phage.

What is specialized transduction

: Specific bacterial genes transferred by lysogenic phage.

What is BSL-1

: Lowest biosafety level with minimal risk organisms.

What is BSL-4

: Highest biosafety level for dangerous pathogens.

Can disinfectants always be used as antiseptics

: No.

What is commercial sterilization used for

: Food preservation.

Why is salt used for preservation

: Creates hypertonic environment.