Chapter 7 Flashcards
Classification and Microorganisms
Describe the basic structure of viruses.
Viruses are composed of nucleic acid surrounded by a protein coat called a capsid.
They have either DNA or RNA, which can be single-stranded or double-stranded.
Describe how antibiotics were discovered.
In 1928, Alexander Fleming discovered penicillin, after noticing that mold growing on a culture plate inhibited bacterial growth.
What are protists and how are they classified?
Protists are microorganisms that are eukaryotes. They are classified as animal-like, plant-like, and fungal-like.
Describe the life cycle of a bacteriophage.
Bacteriophages invade bacteria cells to reproduce, using the host’s machinery to replicate. Once assembled, new bacteriophages are released, destroying the host cell.
Explain how bacteria develop resistance to antibiotics.
Antibiotic resistance results from mutations in the bacterial genome. Resistant bacteria pass on their resistant genes to daughter cells.
Describe the difference between traditional taxonomy and cladistics.
In taxonomy, organisms are classified according to their phenotypes, while in cladistics, they are classified based on their evolutionary relationships and genetic relationships.
Describe the ways in which bacteria are classified.
Bacteria are classified by shape (bacilli, cocci, spiral) and cell wall structure (Gram-positive or Gram-negative).
Explain how vaccines work in the context of the immune system.
Vaccines stimulate the immune system to generate antibodies, preparing it to respond effectively to the harmful virus.
What is the Central Dogma of biology?
The central dogma states that DNA self-replicates and that its information flows from DNA to RNA to protein.
Differentiate between scientific theories and truth claims.
Scientific theories are explanations or models for scientific facts and are not claims to truth. They represent the best scientific understanding at a given time.
Why are viruses considered non-living organisms?
Viruses are widely regarded as non-living because they lack the basic ability to reproduce on their own.
What are the main differences between prokaryotic bacterial cells and eukaryotic protist cells?
Prokaryotic bacterial cells lack a membrane-bound nucleus and organelles, while eukaryotic protist cells contain a membrane-bound nucleus and organelles, making them more complex.
How did Edward Jenner contribute to the Cycle of Scientific Enterprise?
Jenner hypothesized that infecting an individual with cowpox would provide immunity to smallpox.
What is the process of mitosis compared to bacterial cell division?
Mitosis is a complex process involving stages like prophase, metaphase, anaphase, and telophase, while bacterial cell division involves simple DNA replication followed by cell elongation and division.
What are the three major types of biomolecules found in the bacterial cell wall?
The bacterial cell wall contains peptidoglycan, composed of carbohydrates and proteins, and is surrounded by lipids.
How do bacterial cells develop resistance to drugs?
Resistance begins with a mutation in the DNA that provides resistance, followed by multiplication through DNA replication and the production of protective proteins via transcription and translation.
How do plant-like protists carry out photosynthesis?
Photosynthesis in plant-like protists occurs in chloroplasts, where chlorophyll captures sunlight, leading to light-dependent reactions that synthesize ATP and NADPH, followed by the Calvin cycle to produce sugars.
What is the difference between Gram-positive and Gram-negative bacterial cells?
Gram-positive cells have a thick layer of peptidoglycan that retains the violet dye, making them appear purple. Gram-negative cells have peptidoglycan sandwiched between two plasma membranes, causing the crystal violet dye to rinse off.
How are bacteria beneficial in aquatic ecosystems?
Photosynthetic bacteria make up a large part of algae in water ecosystems and are the primary food source for all other aquatic life forms.
What role do soil bacteria play in the ecosystem?
Soil bacteria help break down organic matter and return it to the soil as decomposers.
How do some bacteria recycle elements in the soil?
Some soil bacteria recycle elements such as carbon and nitrogen, transforming ammonia into nitrite or converting nitrogen gas into a useful form of nitrogen
What is bioremediation in relation to bacteria?
Some bacteria metabolize hydrocarbons like gasoline and crude oil, and are used as part of bioremediation.
What is normal flora in humans?
Beneficial bacteria that live inside our intestines help us digest our food.
Name two bacterial diseases.
Strep throat and pink eye are examples of bacterial diseases.
