micro chpt 6 questions Flashcards
(22 cards)
What evolved from early prokaryotic cells?
Cells, organelles (mitochondria, chloroplasts), and major metabolic pathways
This highlights the evolutionary lineage of complex life forms from simpler organisms.
Which types of eukaryotic microbes exhibit fundamental differences from bacteria?
Fungi, protozoa, algae
These organisms carry out some processes similar to bacteria but have distinct cellular structures and functions.
What unique metabolic pathways are exhibited by Bacteria and Archaea?
Nitrogen fixation, methane production, anoxygenic photosynthesis
These pathways demonstrate the metabolic diversity among prokaryotic organisms.
What roles do microbes play in ecosystems?
Essential for life, biogeochemical cycles, plant/animal microbiota, human utilization
Microbes are crucial for nutrient cycling and maintaining ecological balance.
What are the two primary energy sources for microbes?
Light (photosynthesis) or chemical reactions
This distinction is important for understanding microbial energy metabolism.
What is ATP and its main components?
Adenosine (adenine + ribose) and three phosphate groups
ATP is the main energy currency in cells.
What type of bonds in ATP release energy when broken?
High-energy bonds
The energy release is due to the repulsion between negatively charged phosphates.
What is the equation for ATP hydrolysis?
ATP + H₂O → ADP + Pᵢ + free energy
This reaction illustrates how ATP is converted to ADP, releasing energy for cellular processes.
True or False: ATP is stable and does not hydrolyze quickly.
False
ATP is unstable and hydrolyzes quickly, which can lead to energy loss if not coupled with other reactions.
What are the two methods of ATP generation mentioned?
- Transmembrane ion gradients
- Substrate-level phosphorylation
Each method has different efficiency and resource requirements.
What characterizes exergonic reactions?
Energy-releasing, spontaneous (ΔG < 0)
These reactions occur without the input of external energy.
What characterizes endergonic reactions?
Require energy input (ΔG > 0)
These reactions need an external source of energy to proceed.
What is the main end product of glycolysis?
Pyruvate
Glycolysis consists of two phases: energy investment and energy payoff.
What is the purpose of fermentation in microbial metabolism?
Regenerates NAD⁺ for glycolysis
This process allows glycolysis to continue in the absence of oxygen.
What is the main advantage of respiration over fermentation?
Higher ATP yield
Respiration utilizes the electron transport chain for more efficient ATP production.
What does the TCA cycle fully oxidize?
Glucose-derived carbon into CO₂
This cycle produces electron carriers for the electron transport chain.
How is the proton motive force (PMF) generated during respiration?
Electrons transferred through redox enzymes
This process is crucial for ATP synthesis via ATP synthase.
What types of respiration are there?
- Aerobic: Uses oxygen
- Anaerobic: Uses alternative electron acceptors
The type of respiration affects the metabolic pathways used by microorganisms.
What are strict aerobes?
Microorganisms that require oxygen and detoxify reactive oxygen species (ROS)
These organisms have specific adaptations to utilize oxygen safely.
What are microaerophiles?
Microorganisms that require low oxygen and are sensitive to ROS
They thrive in environments with limited oxygen availability.
What distinguishes oxygenic photosynthesis from anoxygenic photosynthesis?
Oxygenic uses water as the electron donor and produces O₂; anoxygenic uses other donors with no O₂ production
This highlights the different mechanisms of energy capture in photosynthetic organisms.
What is the importance of microbial adaptations?
Exploiting all energy sources on Earth
This adaptability allows microbes to thrive in diverse environments and conditions.
