Biochemistry Chapter 8

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Questions and Answers

What process do fatty acids undergo to be transformed into acetyl CoA for entry into the Kreb's cycle?

Beta oxidation (correct)

Lipogenesis

Glycolysis

Fermentation

What is the primary role of catabolic processes within a cell?

To synthesize lipids

To provide energy for building reactions (correct)

To transport nutrients

To build complex molecules

Which type of microorganism must obtain its carbon in an organic form?

Heterotroph (correct)

Phototroph

Autotroph

Chemotroph

Which of the following nutrients is essential for stabilizing cell walls and endospores in bacteria?

Calcium $(Ca)$ Signup and view all the answers

Which nutrient serves as a crucial component of chlorophyll in organisms?

Magnesium $(Mg)$ Signup and view all the answers

What is the outcome for a cell placed in a hypotonic solution?

The cell swells and may burst Signup and view all the answers

Which type of microbe gets its energy from chemical reactions?

Chemotroph Signup and view all the answers

What type of nutrients do macronutrients represent?

Elements required in relatively large amounts Signup and view all the answers

What is the primary goal of sterilization in microbial control?

To eliminate all viable microorganisms Signup and view all the answers

Which method can distinguish between live and dead cells?

Flow cytometer Signup and view all the answers

What does microbial stasis refer to?

Temporary prevention of microbial multiplication Signup and view all the answers

Which antimicrobial agent is commonly used to destroy vegetative pathogens?

Disinfection Signup and view all the answers

What is the effect of surfactants in microbial control?

They act as microbicidal agents by lowering surface tension Signup and view all the answers

What is the primary function of enzymes in metabolism?

To increase the rate of chemical reactions Signup and view all the answers

How does heat function as an antimicrobial agent?

Higher temperatures allow for shorter exposure times Signup and view all the answers

Which statement about microbial death is accurate?

It means permanent loss of reproductive capacity Signup and view all the answers

Which of the following best describes catabolism?

Breaking down macromolecules to produce energy Signup and view all the answers

What happens during enzyme denaturation?

Enzymes lose their functional shape Signup and view all the answers

Microbes can be categorized based on resistance. Which group has the highest resistance?

Bacterial endospores Signup and view all the answers

Which group of microbes is characterized by an optimum temperature below 15°C?

Psychrophiles Signup and view all the answers

Which of the following is true about constitutive enzymes?

Their amounts remain constant in the cell Signup and view all the answers

What type of respiration utilizes $CO3^{2-}$ as a final electron acceptor?

Anaerobic respiration Signup and view all the answers

What is the primary characteristic of facultative anaerobes?

They can grow without oxygen but use it when available. Signup and view all the answers

What is the initial process all three metabolic strategies begin with?

Glycolysis Signup and view all the answers

What defines the optimum temperature for a microorganism?

The temperature at which the fastest growth rate occurs. Signup and view all the answers

During which phase of the growth curve do newly inoculated cells require adjustment before division?

Lag phase Signup and view all the answers

How does the regulation of enzyme synthesis occur?

Via induction or repression mechanisms Signup and view all the answers

What is primarily stored as energy in cells?

ATP Signup and view all the answers

What is a common characteristic of halophiles?

Require high concentrations of salt for growth. Signup and view all the answers

What is the purpose of binary fission in microbial growth?

To enable one cell to become two. Signup and view all the answers

Which type of microbe is harmed by normal atmospheric concentrations of oxygen but requires a small amount for growth?

Microaerophiles Signup and view all the answers

What does the term generation time refer to in microbiology?

The time required for one cell division cycle. Signup and view all the answers

What is the function of the reverse transcriptase enzyme in HIV?

Converts RNA to DNA Signup and view all the answers

What is superinfection?

An overgrowth of drug-resistant microorganisms during therapy Signup and view all the answers

Which test provides data on antimicrobial susceptibility?

Kirby-Bauer technique Signup and view all the answers

Which of the following best describes multi-drug resistant (MDR) pumps?

Proteins that lack specificity in drug transport Signup and view all the answers

What does the minimum inhibitory concentration (MIC) represent?

Smallest concentration that inhibits visible growth Signup and view all the answers

What can cause antimicrobial treatment to fail?

Presence of resistant cells not detected in tests Signup and view all the answers

What is a significant side effect of drug therapy?

Tissue damage due to toxicity Signup and view all the answers

What role does interferon play in the immune response?

Prevents virus replication Signup and view all the answers

What is the thermal death point defined as?

The lowest temperature required to kill all microbes in a sample in 10 minutes. Signup and view all the answers

What is the main goal of pasteurization?

To kill potential infectious agents while preserving flavor and nutritional value. Signup and view all the answers

Which type of radiation is specifically termed ionizing radiation?

Radiation that ejects orbital electrons from atoms, forming ions. Signup and view all the answers

What is a characteristic of quaternary ammonium compounds?

Their effectiveness is reduced when organic matter is present. Signup and view all the answers

What action do intermediate-level germicides primarily target?

Enveloped viruses and fungi. Signup and view all the answers

What is the mechanism by which alcohol inactivates enveloped viruses?

Through its surfactant effect on the viral envelope. Signup and view all the answers

What is the primary active component in hydrogen peroxide that contributes to its germicidal effects?

Hydroxyl free radicals. Signup and view all the answers

What characteristic is associated with ethylene oxide (ETO)?

It alkylates DNA and proteins, inhibiting replication. Signup and view all the answers

Study Notes

Chapter 8 Notes

Metabolism is the sum of all chemical reactions in the body needed to maintain homeostasis. It includes two types:
- Anabolism: building up macromolecules for structure and function
- Catabolism: breaking down macromolecules to produce energy
Enzymes are biological catalysts that speed up chemical reactions by lowering activation energy. They are not part of the products and remain unchanged during the process. Cofactors, like coenzymes, support enzyme function.
Denaturation occurs when weak bonds maintaining an enzyme's shape are broken. This alters the enzyme's shape, preventing substrate attachment to the active site.
Constitutive enzymes are present in consistent amounts, regardless of substrate levels. Regulated enzymes adjust in concentration based on substrate levels.
Enzyme activity can be controlled through induction or repression of synthesis.
Energy is primarily stored as ATP. Oxidation-reduction (redox) reactions transfer energy.

Chapter 7 Notes

Bioelements are essential elements for all living organisms. Macronutrients are needed in large quantities for structural roles. Micronutrients (trace elements) are involved in maintaining enzyme function.
Inorganic nutrients include atoms/molecules other than carbon and hydrogen. Organic nutrients contain both carbon and hydrogen. Examples of essential elements include potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), iron (Fe), and zinc (Zn).
Temperature affects microbial growth. Minimum temperature is the lowest for growth, maximum for highest growth, and optimum for fastest rates. Psychrophiles thrive in cold temperatures, psychotrophs can grow in refrigeration, and thermophiles thrive in high temperatures.
Carbon and energy sources classify microbes. Heterotrophs use organic carbon, and autotrophs use inorganic carbon. Phototrophs obtain energy from light, and chemotrophs from chemical reactions.
Microbial growth patterns include lag phase (initial adjustment), exponential growth (log phase/rapid growth), stationary phase (growth rate = death rate), and death phase (significant cell death).
Different microbes thrive in various environments, with some needing oxygen (aerobes) and others not (anaerobes) and even requiring specific oxygen levels (microaerophiles).
Microbes can grow in acidic (acidophiles) or basic (alkaliphiles) environments. Different organisms have optimal temperature ranges.

Chapter 11 Notes

Contaminants are unwanted microbes.
Decontamination employs physical and chemical agents targeting various groups of microorganisms, with varying degrees of resistance to these agents (highest, moderate, and least).
Sterilization eliminates all types of microbes, including spores. Disinfection reduces the number of undesirable microbes on non-living surfaces.
Methods include heat (moist and dry), radiation (ionizing and non-ionizing), and filtration. Chemical agents like alcohols (disinfectant/antiseptic), halogens (chlorine and iodine), hydrogen peroxide, and quaternary ammonium compounds are also used.

Chapter 12 Notes

Antimicrobial treatment aims to eliminate pathogens without harming the host.
Antibiotics are produced by microbes that kill or inhibit other microbes.
Many mechanisms of action exist, targeting cell walls (e.g., penicillin), nucleic acids (e.g., rifampin, sulfonamides), , protein synthesis (e.g., tetracyclines), and diverse metabolic pathways.
Drug resistance poses challenges. Resistance can occur through various mechanisms in many species of microbes.
Other outcomes of antimicrobial therapy include treatment failure due to drug inability to penetrate a body compartment or the presence of drug-resistant strains.

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Explore the essential concepts of metabolism including anabolic and catabolic processes. Understand the role of enzymes as biological catalysts and the effects of denaturation. This quiz covers key mechanisms of enzyme regulation and energy storage in biological systems.