Exam 3 Flashcards

Question

major bioprocesses of the 21st century

Answer 1

Monoclonal Antibody Production - CHO cells, E. coli, ~$200 billion Cancer, autoimmune diseases, diagnostics Microbial Biofuel Production - S. cerevisiae, E. coli, C. acetobutylicum, ~$100 billion Ethanol, biodiesel; reduced emissions Bioplastics (PHAs) - C. necator, P. putida, ~$10 billion, Biodegradable plastics; packaging, medical devices Synthetic Biology / Pharmaceuticals - S. cerevisiae, ~$5 billion, Artemisinin (malaria drug); complex drug synthesis

Answer 2

the use of microorganisms to produce commercial products on a large scale

Answer 3

a chemical made by a living organism that inhibits or kills other microorganisms

Answer 4

a compound produced by a microorganism through its metabolic pathways

Answer 5

using microorganisms to chemically modify a compound (e.g., steroid hormones)

Answer 6

* The Sumerians (~6,000 years ago) were among the first to brew beer. Early Egyptians used yeast to make leavened bread. * Fermentation was practiced for millennia without any understanding of the microorganisms responsible. * Zymomonas mobilis is a bacterium noted for its efficient fermentation of simple sugars to ethanol.

Answer 7

the microbial conversion of organic compounds (usually sugars) into other products — alcohol, acids, or gases — under anaerobic or partially anaerobic conditions. These products preserve food, alter flavor, and improve nutrition

Answer 8

Saccharomyces cerevisiae (yeast)

Answer 9

Saccharomyces cerevisiae — CO2 causes dough to rise

Answer 10

Lactobacillus, Streptococcus thermophilus — lactic acid fermentation

Answer 11

Lactobacillus species — lactic acid preserves vegetables

Answer 12

Acetobacter — oxidizes ethanol to acetic acid

Answer 13

Aspergillus oryzae (fungus)

Answer 14

Rhizopus oligosporus (mold)

Answer 15

button mushroom, shiitake mushroom, oyster mushroom

Answer 16

Microalgae (single-celled photosynthetic protists) are increasingly explored as sustainable, nutrient-dense food ingredients. Key genera include Spirulina, Chlorella, and Dunaliella, all of which are rich in protein, essential fatty acids, and pigments. * Applications range from dietary supplements to functional food ingredients and even space food research. * Production stages include: cultivation → nutrition analysis → food development → quality control → sensory evaluation → shelf-life testing.

Answer 17

* hypothesis for the origin of life *building of biological molecules from inorganic precursors *Tested by Stanley Miller in 1953 - used methane, ammonia, hydrogen, water vapor, and electrical sparks

Answer 18

*a hypothesis for the origin of life * Life may have come from deep sea vents, reduced compounds rose up and provided raw materials necessary for life with hot water serving as an energy source

Answer 19

*a hypothesis for the origin of life *organic molecules like hydrogen cyanide and formaldehyde, which form in space, could have been delivered to Earth by meteorites, seeding the planet with the building blocks for life

Answer 20

- Photosynthesis probably evolved after glycolysis and anaerobic respiration - 2.7 BYA - release of oxygen as a result of photosynthesis (cyanobacteria) - Oxygen began its steady buildup in the environment - Changed the environment - O2 + UV radiation = O3 (ozone) - Ozone can absorb UV radiation like a shield and protect living things so they can spread out across Earth - The first microorganisms were anaerobic - When O2 became abundant, anaerobic bacteria avoided O2 - Other lineages detoxified oxygen by reducing it to water - Releases energy to make ATP - Aka ETC for aerobic respiration, first evolved as an oxygen detoxification system

Answer 21

- the idea that current DNA world was preceded by an RNA world in which RNA, rather than DNA, was the genetic material - Ribozymes - enzymes made from RNA (Can catalyze the synthesis of new RNA) - RNA can store information and catalyze reactions - simple metabolism bc can't catalyze reactions as efficiently as proteins

Answer 22

- small, spherical compartments when phospholipids are mixed with water - May have formed first cells when incorporated self-replicating RNA - Swallowed other liposomes because of semipermeability

Answer 23

Better suited for storing information of large molecules

Answer 24

The first prokaryotes, likely obligar anaerobes, fossilized stromatolites, and layered sedimentary rock formations contain microbial fossils resembling modern filamentous and rod-shaped bacteria

Answer 25

- Mitochondria and chloroplasts came from aerobic prokaryotes and their symbiotic relationship with anaerobic eukaryotic cells

Answer 26

caused the atmosphere to oxygenate, once cells could extract energy from biological molecules like glucose, the ability to synthesize their own molecules through photosynthesis became advantageous, cyanobacteria

Answer 27

- 2015 European scientists - More closely related to eukaryotes than any other archaea - Link between Eukaryotic and Prokaryotes

Answer 28

- The first multicellular organisms appeared around 1.5 billion years ago. - Initially, some unicellular eukaryotes formed colonies, marking a transition from single-celled to multicellular life. - As cells in these colonies became specialized, true multicellular organisms evolved, leading to a variety of cell types seen in modern animals, fungi, and plants. - Advantages of Multicellularity: - Size and Protection: Larger organisms are less likely to be consumed by predators. - Internal Regulation: Multicellular organisms can better maintain stable internal conditions, such as temperature. - Mutational Safety: In multicellular organisms, mutations affecting individual cells are less harmful compared to unicellular organisms, where a single mutation can be fatal

Answer 29

process by which favorable heritable traits become more common in a population over generations * Mutations introduce new genetic variation into a population. They can arise spontaneously or be caused by mutagens (UV light, chemical agents). * The environment cannot induce a specific mutation; it can only select for or against mutations that already exist. * Once a mutation arises, natural selection acts on it if the mutation affects an organism's survival or reproduction. * Unfavorable mutations: organisms carrying them reproduce less successfully and are removed from the population over time. * Favorable mutations: organisms carrying them reproduce more successfully, so the new genotype gradually replaces the old one KEY CONCEPTS: * Mutations are RANDOM — the environment selects, but does not direct. * Favorable mutation → survives & reproduces more → spreads through population. * Unfavorable mutation → fails to reproduce → removed from population.

Answer 30

mistakes made during DNA replication

Answer 31

* A random mutation may alter a bacterium's structure so an antibiotic can no longer bind or kill it. * In the presence of that antibiotic, resistant bacteria survive and reproduce while susceptible ones die. * The resistant genotype quickly becomes dominant in the population.

Answer 32

a glycopeptide antibiotic; resistance arises from altered peptidoglycan amino acids - Vancomycin is a 'last-resort' antibiotic used against Gram-positive bacteria. It normally works by blocking peptidoglycan synthesis — specifically, it prevents new NAM/NAG repeating units from being added to the bacterial cell wall. * Normal susceptible bacteria: Vancomycin binds the amino acids on NAM, blocking cell wall synthesis. * Resistant bacteria: A mutation alters the amino acids in peptidoglycan, so vancomycin can no longer bind. Cell wall synthesis continues unimpeded.

Answer 33

1. Efflux Pump - Bacteria actively pump the antibiotic out of the cell. Efflux pumps are nonspecific and can remove many different drugs. ex. Ciprofloxacin 2. Target Mutation - A mutation in the antibiotic's target prevents the drug from binding. ex. Rifampicin 3. Bypass / Avoidance - The bacterium acquires a different, antibiotic-insensitive enzyme to carry out the same step the drug would block. ex. Methicillin (MRSA) 4. Permeability Barrier - The cell membrane becomes less permeable to the antibiotic, often through charge modifications. Nonspecific. ex. Antimicrobial peptides

Answer 34

* The virulence (harmfulness) of a pathogen can evolve in response to how it is transmitted. * Vector-borne pathogens (transmitted year-round) tend to evolve higher virulence because they do not depend on a mobile host. * Example: Myxoma virus — in Australia it is mosquito-transmitted (seasonal) → lower virulence; in England it is flea-transmitted (year-round) → higher virulence.

Answer 35

the idea that hosts and parasites co-evolve in an ongoing arms race, favoring sexual reproduction Why did sexual reproduction evolve if asexual reproduction is faster and more efficient? * The Red Queen hypothesis proposes that pathogens impose continual selection pressure on hosts, favoring genetic diversity. * Sexual reproduction creates genetic diversity, which means some individuals in the host population will always carry genotypes the pathogen cannot easily infect. * As pathogens evolve to infect the most common host genotype, rare resistant genotypes survive and reproduce maintaining diversity. * This evolutionary 'arms race' helps host populations avoid extinction from rapidly evolving pathogens.

Answer 36

Morning sickness (nausea and vomiting in early pregnancy) may be an evolutionary adaptation, not just a side effect. * Hypothesis: The immune system is temporarily suppressed during early pregnancy to prevent rejection of the fetus. This makes the mother more vulnerable to pathogens in food. * Morning sickness peaks during the first trimester — when organ development is most sensitive to toxins. * Foods that most often trigger nausea include meat (highest pathogen risk), caffeinated drinks, and vegetables containing natural pesticides. * Women who experience morning sickness have lower rates of miscarriage, suggesting it may be protective.

Answer 37

* Ecology focuses on two broad categories of factors: ○ Biotic factors — interactions with other living organisms (predation, competition, mutualism, parasitism) ○ Abiotic factors — non-living environmental conditions (soil chemistry, temperature, pH, water availability, oxygen levels) * The prevalence of any organism in an environment depends on both of these factor types.

Answer 38

All individuals of the same species in a defined area

Answer 39

All species living together in a defined area and their interactions

Answer 40

A community plus all its abiotic factors

Answer 41

All ecosystems on Earth combined

Answer 42

* Primary Producers (Phototrophs) — capture energy from sunlight (or chemicals) and convert it to organic molecules. They form the base of all food webs. Examples: plants, algae, cyanobacteria. * Primary Consumers (Herbivores) — eat producers. * Secondary Consumers (Carnivores) — eat herbivores. * Tertiary / Quaternary Consumers — eat secondary or tertiary consumers. * Decomposers (Saprophytes) — break down dead organic matter at all levels; recycle nutrients back to producers. Examples: bacteria, fungi.

Answer 43

Energy is lost as heat at every trophic level. On average, only 10% of energy is passed from one level to the next. * Example: 100 kg of grass → supports only 10 kg of herbivore → supports only 1 kg of carnivore. * This is why producers always have the highest biomass and top predators the lowest. * Only ecosystems with very high primary productivity can support tertiary or quaternary consumers. * Nutrients (iron, phosphorus, etc.) are recycled by decomposers, but energy flows one way and is lost as heat.

Answer 44

Microbes live in microenvironments — tiny zones immediately surrounding the organism where conditions can differ dramatically from the bulk environment. * Microbial biochemical activity can significantly alter local pH, oxygen levels, and ion concentrations. * Within a single soil particle: oxygen-rich surfaces support aerobic microorganisms; oxygen-depleted interiors harbor anaerobes. * A distance of 4 mm for a bacterium is equivalent to several kilometers for a large mammal — microbes experience their environment on a completely different scale. * Microenvironments allow organisms with very different requirements (e.g., acidophiles and non-acidophiles) to coexist within millimeters of each other.

Answer 45

Mutualism - Both partners benefit (+/+), Gut bacteria produce vitamins for the host Commensalism - One benefits, the other is unaffected (+/0), Skin normal flora Parasitism/Pathogenesis - Parasite benefits, host is harmed (+/−), Pathogenic bacteria causing infection Competition - Both are harmed (−/−), Two species competing for the same nutrient Predation - Predator benefits, prey is harmed (+/−) Protists consuming bacteria

Answer 46

formation of earth --> first prokaryotes --> first oxygen-yeilding photosynthetic organisms --> first eukaryotes --> change from primarily reducing to primarily oxidizing atmosphere; beginnings of ozone layer --> first multicellular organisms --> age of dinos --> first humans

Exam 3 Flashcards

(73 cards)