Exam 1 Flashcards
What are the similarities between bacteria and archaea?
Both are prokaryotes.
What is a key difference between bacteria and archaea?
Bacteria can cause disease, while archaea must be separated.
What are the basic characteristics of a virus?
Viruses are noncellular microbes that inject DNA into a host to make copies.
What was Pasteur’s spontaneous generation experiment?
It involved exposure to strands that weaken bacteria and included a chicken experiment.
What is Koch’s Postulate?
It links organisms to the diseases they cause through a series of steps: found, isolated, introduced.
For what disease was the first vaccine developed?
Smallpox.
What is the endosymbiotic theory?
It suggests that prokaryotes were taken into a cell and evolved into eukaryotic organelles.
How do you write the scientific name of an organism?
The scientific name is written with the genus name first, followed by the lowercase species name, both italicized.
How did Alexander Fleming discover penicillin?
He found that mold killed bacteria and used the mold to treat infections.
Who discovered that an attenuated strain of a microbe can initiate immunity?
Louis Pasteur.
Define endemic, epidemic, and pandemic.
Endemic: always present; Epidemic: increases rapidly; Pandemic: spreads worldwide.
What is LD50?
LD50 is the maximum lethal dose; the one that requires fewer cells to kill is more pathogenic.
What are the stages of infectious disease?
Incubation: after infection; Prodromal: symptoms appear; Illness: symptoms peak; Decline: symptoms decrease; Convalescence: recovery.
What are the modes of transmission for infectious diseases?
Direct: touching; Indirect: sneezing; Vertical: bacteria on something.
What host factors influence susceptibility to infectious disease?
Age, health behaviors, environment, genetics.
What is the difference between pathogenicity and virulence?
Pathogenicity is the ability to cause disease; virulence refers to the severity of the disease.
What is the difference between signs and symptoms?
Signs are objective indicators; symptoms are subjective experiences.
What is the difference between opportunistic pathogens and primary pathogens?
Primary pathogens can make anyone sick; opportunistic pathogens are less likely to cause disease in a host.
What are the various levels of protein structure?
Primary: linear; Secondary: regular short patterns (alpha and beta); Tertiary: 3D structure.
What is the function of enzymes?
Enzymes are catalysts that speed up chemical reactions and raise activation energy.
What are the building blocks of macromolecules?
Lipids include fatty acids, triglycerides, and phospholipids; sugars are simple carbohydrates in a chain or ring.
What type of bond holds the two complementary strands of DNA together?
A double helix.
What molecules can freely diffuse across the cell membrane?
Hydrophobic molecules can freely move; charged polar molecules can somewhat; uncharged polar molecules and ions are impermeable.
What is the difference between isotonic, hypotonic, and hypertonic solutions?
Isotonic: no change; Hypertonic: volume shrinks; Hypotonic: expands. The bacterial cell wall protects against hypotonic solutions.
What is the difference between endocytosis and phagocytosis?
Endocytosis takes substances in; phagocytosis is a form of endocytosis known as ‘cell eating.’
What happens when a phagosome fuses with a lysosome?
Particles are digested as lysosomes break them down.
What is the difference between active and passive transport?
Active transport moves against the gradient, while passive transport moves with the gradient.
What is the difference between symport and antiport?
Symport moves substances in the same direction, while antiport moves substances in opposite directions.
What is coupled transport?
Coupled transport involves the simultaneous transport of two substances, one of which is typically moving against its gradient.
What are the structures of Gram-positive and Gram-negative cell envelopes?
Gram-positive has thick multiple layers of peptidoglycan, while Gram-negative has a single layer with lots of lipids and contains LPS.
What is the basic function of pili?
Pili, made up of pillin, help bacteria stick and share extra DNA with one another.
What is the function of flagella?
Flagella rotate and are free-moving, propelling the cell.
What is chemotaxis?
Chemotaxis is the movement of cells in response to chemical signals, facilitated by the rotation of flagella.
What bacterial structure is the target of penicillin?
The target of penicillin is the peptidoglycan layer in bacterial cell walls.
What happens at each stage of bacterial growth?
In the lag phase, bacteria adapt; in the log phase, they multiply rapidly; in the stationary phase, growth levels off; and in the death phase, they die off.
What is osmolarity?
Osmolarity is a measure of the number of molecules in a solution, often referring to salt concentration.
What does it mean when we say bacteria grow exponentially?
It means the population doubles in size.
What is a thermophile?
A thermophile is an organism that thrives at high temperatures.
What is a mesophile?
A mesophile is an organism that grows at normal standard temperatures.
What is a psychrophile?
A psychrophile is an organism that thrives at low temperatures.
What is the difference between chemotroph and heterotroph?
Chemotrophs obtain energy from light, while heterotrophs obtain compounds from other organisms.
What is the difference between lithotroph and organotroph?
Lithotrophs use inorganic compounds for energy, while organotrophs use organic compounds.
What is the nitrogen fixation step in the nitrogen cycle?
Nitrogen is removed from the air and converted to ammonia, then to nitrate.
How are bacteria classified with regard to oxygen requirements?
Bacteria can be classified as aerobic, anaerobic, or facultative, depending on their oxygen needs.
Which bacteria are sensitive to reactive oxygen species (ROS)?
Anaerobic bacteria are typically sensitive to reactive oxygen species.
