BIOS242 Exam 2 Review Live Lecture Flashcards

Chemotrophs

Obtain energy from chemicals such as organic compounds or inorganic substances, allowing them to produce ATP for cellular processes.

THINK: They play a crucial role in ecosystems by contributing to nutrient cycling.

Phototrophs

Obtain energy from sunlight through photosynthesis using chlorophyll or other pigments.

THINK: They are essential for converting solar energy into chemical energy, supporting food webs.

Organotrophs

Obtain energy by oxidizing organic compounds, such as carbohydrates and fats.

THINK: They are vital for recycling organic matter and supporting food chains.

Lithotrophs

Obtain energy by oxidizing inorganic compounds, such as hydrogen sulfide, ammonia, and iron.

THINK: They are important for energy acquisition in environments lacking organic substrates, contributing to biogeochemical cycles.

Heterotrophs

Obtain carbon from organic molecules such as carbohydrates, proteins, and lipids.

THINK: They rely on other organisms for energy and carbon, playing a key role in ecosystem dynamics.

Autotrophs

Obtain carbon from inorganic molecules such as carbon dioxide and use sunlight or chemical energy for their energy needs.

THINK: They are primary producers in ecosystems, forming the base of the food web by converting inorganic materials into biomass.

Saprobes

Obtain their nutrients from dead organisms

THINK: They play a crucial role in decomposition and nutrient cycling within ecosystems.

Parasites

Obtain their nutrition from living organisms

THINK: They often harm their hosts while benefiting from the relationship, influencing population dynamics and ecosystem health.

Psychrophile

A type of organism that thrives in extremely cold environments, typically below 15°C. They are important for nutrient cycling in polar and high-altitude ecosystems.

THINK: They are adapted to low temperatures and play a key role in breaking down organic matter in cold habitats.

Psychrotolerant

Describes organisms that can grow at low temperatures but optimum growth occurs at warmer temperatures, typically above 20°C. They are often found in temperate environments.

THINK: They can survive in cold but prefer milder conditions.

Mesophile

A type of organism that thrives in moderate temperature ranges, typically between 20°C and 45°C. They are commonly found in many terrestrial and aquatic environments, where they play a crucial role in decomposition and nutrient cycling.

THINK: They are well-suited for environments like soils and human bodies, contributing significantly to ecosystem processes.

Thermophile

A type of organism that thrives in high temperatures, typically above 45°C. They are often found in environments such as hot springs and hydrothermal vents, playing a key role in biogeochemical cycles.

THINK: They are adapted to extreme heat and can withstand temperatures that would denature proteins in most other organisms.

Extreme thermophile

A type of organism that thrives at extremely high temperatures, typically above 80°C. They are often found in environments like deep-sea hydrothermal vents and hot springs, where they are adapted to survive intense heat and pressure.

THINK: They are specialized to withstand extreme thermal conditions, often producing unique enzymes that function optimally at high temperatures.

Obligate aerobe

Requires oxygen and cannot survive without it.

THINK: They typically undergo aerobic respiration to generate energy, making them essential for oxygen-rich environments.

Facultative anaerobe

Uses oxygen but can survive without it.

THINK: They can switch between aerobic respiration and fermentation, allowing them to thrive in both oxygen-rich and oxygen-poor environments.

Aerotolerant anaerobe

Does not use oxygen but can grow in its presence.

THINK: These organisms rely exclusively on fermentation for energy and are not harmed by oxygen.

Obligate anaerobe

Unable to use oxygen and cannot survive if it is present.

THINK: These organisms rely on anaerobic respiration or fermentation for energy, thriving in oxygen-free environments.

Microaerophile

Uses oxygen but only at very low concentrations.

THINK: These organisms require oxygen for growth but are harmed by higher levels, often found in environments like soil or water.

Acidophile

• Require an acidic environment for growth (below pH 6).

• Molds and yeasts tolerate acid.

THINK: These organisms often thrive in environments such as acidic soils or acidic waters.

Alkalinophile

• Live in a pH above 8

• Live in hot pools and soils

THINK: These organisms thrive in alkaline environments, often found in places like soda lakes or alkaline soils.

Neutrophile

Grow in habitats between pH 6 and 8.

THINK: These organisms thrive in neutral pH environments, including most soils and aquatic environments.

Halophile (Osmotic Pressure)

Prefer high concentrations of salt for growth

THINK: These organisms are often found in saline environments, such as salt lakes or salt mines.

Barophile (Atmospheric Pressure)

Deep-sea microbes that exist in pressures up to 1000 times atmospheric pressure.

• REQUIRE high pressure.

THINK: These organisms thrive in extreme pressure environments, such as the deep ocean.

Lag Phase

The initial period in microbial growth when cells are adjusting to their environment and not yet dividing. During this phase, metabolic activity increases as cells prepare for division.

THINK: This phase can vary in length depending on the organism and environmental conditions.

Exponential Growth Phase (Log Phase)

The phase in microbial growth where cells divide at a constant and rapid rate, leading to a big increase in population. This phase is characterized by optimal conditions for growth.

THINK: This phase follows the lag phase and precedes the stationary phase.

Stationary Phase

The phase in microbial growth where the rate of cell division slows and stabilizes as resources become limited and waste products accumulate. In this phase, the population size remains relatively constant as growth and death rates balance out.

THINK: This phase often follows the exponential growth phase and can lead to nutrient depletion.

Death Phase

The phase in microbial growth where the rate of cell death exceeds the rate of cell division, leading to a decline in the overall population. This usually occurs after the stationary phase when resources are significantly depleted and waste accumulation becomes toxic.

THINK: This phase marks the end of growth and results in the eventual extinction of the population if conditions do not improve.

Metabolism

The sum of all biochemical reactions occurring within a cell or organism, including catabolism and anabolism.

THINK: Essential for maintaining life, providing the energy and building blocks necessary for growth, repair, and maintenance of cellular functions.

Anabolism

The set of metabolic pathways that construct molecules from smaller units, using energy in the process.

THINK: This process is crucial for growth, cell differentiation, and maintaining cellular structures.

Catabolism

The set of metabolic pathways that break down molecules into smaller units, releasing energy in the process.

THINK: This process is essential for energy production, providing the necessary fuel for anabolic reactions and overall cellular activity.

Substrates

The reactants in a biochemical reaction that an enzyme acts upon, leading to the formation of products.

THINK: Crucial for enzyme activity, influencing reaction rates and pathways in metabolism.

Active Site

The specific region of an enzyme where substrate molecules bind and undergo a chemical reaction.

THINK: Essential for catalyzing biochemical reactions effectively.

Specificity of Enzyme-Substrate Interactions

Refers to the ability of an enzyme to selectively bind to a specific substrate based on the shape and chemical properties of the active site. This selectivity ensures that enzymes catalyze only particular reactions, critical for metabolic efficiency.

THINK: Substrates must fit the active site appropriately for the enzyme to catalyze the reaction.

Exoenzymes

Enzymes that are secreted outside the cell to catalyze reactions in the external environment. They play a key role in digestion and nutrient absorption.

THINK: These enzymes break down large molecules into smaller ones, allowing for easier uptake by cells.

Endoenzymes

Enzymes that function within the cell, often involved in metabolic pathways. They catalyze reactions necessary for cellular processes and are not secreted outside the cell.

THINK: Essential for internal metabolic reactions.

Competitive Inhibition

A form of enzyme inhibition where a molecule similar to the substrate competes for binding to the active site. This reduces the rate of reaction by preventing substrate binding, which can be overcome by increasing substrate concentration.

THINK: In this type of inhibition, the inhibitor resembles the substrate and occupies the active site, thus blocking access for the actual substrate.

Noncompetitive Inhibition

A form of enzyme inhibition where an inhibitor binds to an enzyme at a site other than the active site, reducing its activity regardless of substrate concentration. This prevents the enzyme from functioning optimally without directly blocking substrate access.

THINK: The inhibitor alters the enzyme's shape, leading to decreased reaction rates even with high substrate levels.

Aerobic Respiration

The process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water. It involves glycolysis, the Krebs cycle, and the electron transport chain.

THINK: Requires oxygen to produce energy efficiently.

Anaerobic Respiration

The process in which cells convert glucose into energy (ATP) without the use of oxygen, resulting in byproducts like lactic acid or ethanol, depending on the organism.

THINK: Occurs in low-oxygen environments and leads to less efficient energy production.

Fermentation

A metabolic process that converts sugars to acids, gases, or alcohol in the absence of oxygen. It occurs in many microorganisms and some higher organisms, playing a crucial role in energy production under anaerobic conditions.

THINK: Used in brewing and baking.

Glycolysis

The first step of both aerobic and anaerobic respiration. It breaks down glucose into two molecules of pyruvate, producing a small amount of ATP and NADH in the process.

THINK: This process occurs in the cytoplasm and does not require oxygen.

Krebs Cycle (Cross-Roads of Metabolism)

A series of enzymatic reactions in cellular respiration that occurs in the mitochondria, converting acetyl-CoA into carbon dioxide and generating high-energy molecules like NADH and FADH2.

THINK: This cycle is crucial for aerobic respiration and produces ATP indirectly through oxidative phosphorylation.

Aerobic Respiration Electron Acceptor

Oxygen

Think: Allows the electron transport chain to function effectively. It accepts electrons at the end of the chain, enabling the production of ATP during cellular respiration.

Anaerobic Respiration Electron Acceptor

Any molecule other than oxygen, such as nitrate, carbonate, or sulfate.

THINK: These molecules serve as terminal electron acceptors, allowing cells to produce energy without oxygen.

Fermentation Final Electron Acceptor

Organic molecules, typically pyruvate or derivatives, that accept electrons, allowing for the regeneration of NAD+.

THINK: This process allows for ATP production without the use of oxygen, primarily in anaerobic conditions.

Produces Substrates For Krebs Cycle

Catabolism of glucose, proteins, and fatty acids.

THINK: This process yields acetyl-CoA and other intermediates that enter the Krebs cycle, facilitating cellular respiration and energy production.

Eukaryotes Catabolism of Glucose

Glycolysis: Cytosol

Krebs Cycle: Mitochondrial Matrix

Electron Transport: Mitochondrial Inner Membrane

Prokaryotes Catabolism of Glucose

Glycolysis: Cytosol

Krebs Cycle: Cytosol

Electron Transport: Plasma Membrane

Amphibolism

The process that integrates catabolic and anabolic pathways, allowing for the conversion of substrates into energy and biosynthetic precursors. It plays a vital role in metabolism, facilitating the use of intermediates from the Krebs cycle for both energy production and the synthesis of biomolecules.

THINK: Critical for balancing energy needs with building block requirements, enabling organisms to adapt to varying nutritional and environmental conditions.

• A given molecule can serve multiple purposes to derive maximum benefit from all nutrients and metabolites

• Catabolic and anabolic pathways are integrated to improve cell efficiency

Pyruvate Precursor

Provides intermediates for amino acids.

Acetyl CoA Precursor

Involved in synthesis and break down of fatty acids.

Decontamination

The mechanical removal of most microbes from an animate or inanimate surface.

THINK: Essential for infection control and reducing microbial load on surfaces.

Sterilization

The destruction of ALL microbial life, including viruses and endospores.

THINK: Important for surgical instruments and practices to prevent infection.

Disinfection

Destroys most microbial life (vegetative pathogens), reducing contamination of inanimate surfaces. Does NOT remove endospores.

THINK: Essential for sanitization of medical equipment and surfaces.

Antisepsis

The same as disinfection, but on a living surface.

THINK: Essential for preventing infections in wounds and surgical sites.

Physical Agents

Methods used to eliminate or reduce microbial contamination, such as heat, radiation, and filtration.

THINK: Utilized in sterilization and disinfection processes to maintain hygiene.

Chemical Agents

Substances used to destroy or inhibit microbial growth on surfaces or in liquids. Examples include alcohols, chlorines, and phenols.

THINK: Critical in disinfecting and sterilizing environments.

Mechanical Removal Methods

Techniques including filtration, scrubbing, and washing that physically remove microbes from surfaces.

THINK: Effective in maintaining cleanliness and preventing infections.

Antimicrobials

All-inclusive term for any antimicrobial drug, regardless of what type of microorganism it targets.

THINK: Includes antibiotics, antifungals, and antivirals used in infection treatment.

Antibiotics

Substances produced by the natural metabolic processes of some microorganisms— or created by scientists— that can inhibit or destroy microorganisms; generally, the term is used for drugs targeting bacteria and not other types of microbes.

THINK: Often used to treat bacterial infections.

Semisynthetic Drugs

Drugs that are chemically modified in the laboratory after being isolated from natural sources.

THINK: These drugs combine natural and synthetic elements to enhance effectiveness.

Synthetic Drugs

Drugs produced entirely by chemical reactions within a laboratory setting

THINK: Typically designed to mimic natural compounds or improve efficacy.

Broad-Spectrum Antibiotics

Antibiotics effective against a wide range of bacteria, both gram-positive and gram-negative.

THINK: These antibiotics are particularly useful when the specific type of bacteria is unknown and can treat various infections.

Narrow-Spectrum Antibiotics

Antibiotics that are effective against specific types of bacteria, either gram-positive or gram-negative. They are often used when the bacterial cause of an infection is known.

THINK: These antibiotics help minimize disruption to beneficial microbiota and reduce the risk of resistance.

Protein Synthesis Inhibitors Acting on Ribosomes

These are antibiotics that target the process of protein synthesis by binding to ribosomes, effectively preventing bacteria from producing essential proteins necessary for their growth and survival. Examples include tetracyclines and macrolides.

Folic Acid Synthesis in the Cytoplasm

The process by which bacteria produce folic acid in the cytoplasm, crucial for nucleic acid synthesis and cell growth. Inhibitors of this pathway, such as sulfonamides, can effectively hinder bacterial proliferation.

Cell Wall Inhibitors

Antibiotics that disrupt the synthesis of bacterial cell walls, leading to cell lysis and death. Common examples include penicillins and cephalosporins.

Cytoplasmic Membrane Inhibitors

These are antibiotics that target the bacterial cytoplasmic membrane, disrupting its integrity and function, which can lead to cell death. Examples include polymyxins and daptomycin.

DNA/RNA Inhibitors

Antibiotics that interfere with the synthesis of nucleic acids in bacteria, affecting replication and transcription processes. Common examples include rifamycins and fluoroquinolones.

How Antimicrobial Resistance Arises: Spontaneous Mutations

Minimal chance that the mutation will be advantageous.

• Smaller chance that the mutation will confer drug resistance

• Large microbial populations and constant rate of mutation ensures that such mutation do occur

How Antimicrobial Resistance Arises: Horizontal Gene Transfer

Resistance (R) factors: Plasmids transferred through conjugation, transformation, or transduction

• Transposable drug resistance sequences (transposons): Duplicated and inserted from one plasmid to another or from the plasmid to the chromosome

Penicillins

• Can be obtained naturally or synthesized in the laboratory

• Consists of three parts: Thiazolidine ring, B-Lactam ring, Variable side chain

The B-Lactamase produced by some bacteria can break the B-Lactam ring and inactivate the drug

How Antibiotic Resistance Happens

1. Lots of bacteria. A few are drug-resistant

2. Antibiotics kill most of the bacteria causing the illness (the ones sensitive to the drug). Usually this is enough to stop the disease progression.

3. But the drug-resistant bacteria are now allowed to grow and take over.

4. Some bacteria give their drug-resistance to other bacteria, causing more problems.

Human Role in Antimicrobial Resistance

• Use of antibiotics in healthy livestock

• Not finishing antibiotic courses

• Treating viruses with antibiotics have all led to increased antibiotic resistance

• Using broad-spectrum instead of narrow-spectrum antibiotics

• Excess antimicrobial drugs are exported to countries with fewer drug regulations

Symbiotic

Organisms live in close nutritional relationships; required by one or both members

Mutualism

Both members benefit

Commensalism

The commensal benefits; other member not harmed.

Parasitism

Parasite is dependent and benefits; host harmed.

Nonsymbiotic

Organisms are free-living; relationships not required for survival.

Synergism

Members cooperate and share nutrients.

Antagonism

Some members are inhibited or destroyed by others.

Microbial Antagonism

• The general antagonistic effect “good” microbes have against intruder microorganisms

• Microbes in a steady, established relationship are unlikely to be displaced by incoming microbes

• Lactobacilli in the vagina prevent overgrowth of yeast

Opportunistic Pathogens

Cause disease when:

• The host’s defenses are compromised

• When they become established in a part of the body that is not natural to them

• When normal biota is introduced to a site that was previously sterile or the patient is immunocompromised

• Streptococcus pneumoniae, often carried as normal biota, causes pneumococcal pneumonia in AIDS patients

Biosafety Level 1 Example

Lactobacillus found in your morning yogurt

Biosafety Level 2 Example

• E. coli that is normally found in your gut

• Staphylococcus aureus

  

Biosafety Level 3 Example

HIV

Biosafety Level 4 Example

Ebola

Exotoxin

• Secreted by a living bacterial cell to the infected tissues

• Many types (botulism toxin, tetanus toxin, diptheria toxin)

  

Endotoxin

• Not actively secreted

• Lipopolysaccharide (LPS) sheds from the outer membrane of gram-negative bacteria (exclusively)

  

Incubation Period

Time from initial contact with the infectious agent to the appearance of first symptoms

Prodromal Period

Earliest symptoms of infection appear

Acute Phase

Infectious agent multiplies at high levels, exhibits greatest virulence, and establishes in target tissue

Convalescent Stage

Patient responds to infection and symptoms decline

Continuous Period

The phase in which the infection persists and symptoms are stable, often with fluctuating severity.

Living Reservoirs

Hosts in which infectious agents live and multiply, contributing to disease transmission. Examples: humans, animals, environment.

Nonliving Reservoirs

Environmental sources that harbor pathogens, such as soil, water, and contaminated surfaces.

Vertical Transmission

Infectious agents are passed from parent to child.

Horizontal Transmission

Disease spread through a population from one infected individual to another.

Direct Transmission

Infectious agents are passed directly from one host to another host

Indirect Transmission

Infectious agents are passed from a host to a vehicle to a new host

• Fomites

• Vehicle (air, soil, food)

• Parenteral (deeper tissue)

• Oral-fecal