Biosphere Basics
What is the primary source of energy for most ecosystems?
What is the sun?
What organelle is responsible for photosynthesis in plant cells?
The Chloroplast
Define cellular respiration.
A process in which glucose is broken down in the presence of oxygen to produce ATP, carbon dioxide, and water.
Define "ecosystem."
A biological community of interacting organisms (biotic) and their physical (abiotic) environment.
What is the main function of the circulatory system?
To transport oxygen, nutrients, and waste throughout the body.
What is the first law of thermodynamics, and how does it relate to energy in the biosphere?
Energy cannot be created or destroyed; it is transformed or transferred within ecosystems.
Write the chemical equation for cellular respiration.
Glucose + Oxygen → Carbon dioxide + Water + Energy (ATP).
Why is chlorophyll essential for photosynthesis?
Chlorophyll absorbs light energy, which drives the reactions of photosynthesis.
What is "carrying capacity"?
The maximum population size an environment can sustain based on resource availability.
How does the digestive system break down food?
Through mechanical digestion (chewing and churning) and chemical digestion (enzymes breaking down molecules).
Describe the process of the water cycle and its importance in the biosphere.
The water cycle includes evaporation, condensation, precipitation, infiltration, and transpiration. It ensures water availability and supports life processes.
How do photosynthesis and cellular respiration relate to each other?
Photosynthesis produces glucose and oxygen used in cellular respiration, which generates energy and releases carbon dioxide and water for photosynthesis.
What role does ATP play in cells?
ATP stores and releases energy for cellular processes like growth, repair, and movement.
Explain the role of nitrogen-fixing bacteria in ecosystems.
These bacteria convert atmospheric nitrogen into ammonia, making it available for plants to use in growth.
What is the purpose of gas exchange in the respiratory system?
To deliver oxygen to the blood and remove carbon dioxide from the body.
Explain the role of decomposers in an ecosystem.
Decomposers break down organic matter, recycling nutrients back into the soil for use by plants.
Explain the role of the electron transport chain in cellular respiration and its relationship to ATP production.
The electron transport chain uses high-energy electrons from NADH and FADH2 to pump protons across the mitochondrial membrane, creating a gradient. This gradient drives ATP synthesis through ATP synthase, producing the majority of ATP in cellular respiration.
How does anaerobic respiration differ from aerobic respiration, and why is it less efficient in terms of ATP production?
Anaerobic respiration occurs without oxygen and produces ATP through glycolysis followed by fermentation, yielding only 2 ATP per glucose molecule. Aerobic respiration uses oxygen, producing up to 36 ATP per glucose via the complete breakdown of glucose in the mitochondria.
How does biomagnification affect top predators?
Toxins like pesticides accumulate in higher concentrations at each trophic level, posing health risks to top predators.
Describe the process of filtration in the nephron and identify the structures involved.
Filtration occurs in the glomerulus within Bowman's capsule. Blood pressure forces water, ions, and small molecules like glucose and urea out of the blood into the filtrate, while larger molecules and blood cells remain in the bloodstream.
How does the albedo effect influence global ecosystems?
High albedo (e.g., ice and snow) reflects sunlight, reducing heat absorption, while low albedo surfaces increase heat absorption, influencing temperature and ecosystems.
Describe how the digestive and circulatory systems work together to maintain homeostasis.
The digestive system breaks down food into nutrients, which the circulatory system distributes to cells for energy production.
Compare the efficiency of light-dependent and light-independent reactions in photosynthesis.
Light-dependent reactions produce ATP and NADPH, fueling the light-independent reactions (Calvin Cycle), which convert carbon dioxide into glucose.
Discuss how invasive species can disrupt the balance of an ecosystem, using a specific example.
Invasive species outcompete native species for resources, disrupt food webs, and alter habitats. For example, zebra mussels in North American waterways filter plankton, depleting food for native aquatic species and altering water chemistry.
Describe the process by which oxygen is transported from the lungs to tissues and how carbon dioxide is removed from tissues.
Oxygen binds to hemoglobin in red blood cells in the lungs and is transported to tissues, where it diffuses into cells. Carbon dioxide diffuses out of tissues, is carried in the blood (as bicarbonate ions, bound to hemoglobin, or dissolved), and is exhaled via the lungs.