Cellular Respiration and Ecosystem Energy Flow in Biology

Why do all organisms need energy?

To grow, survive, and reproduce.

What biomolecules do organisms obtain energy from?

Carbohydrates and lipids.

What is the process called in which cells break down glucose?

Cellular respiration.

What are the main products of cellular respiration?

Carbon dioxide and water.

What is the chemical equation for cellular respiration?

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O.

What is produced during cellular respiration that is used for cellular processes?

ATP (adenosine triphosphate).

What type of process is cellular respiration?

An exothermic process.

What are the three major stages of cellular respiration?

Glycolysis, citric acid cycle (Krebs cycle), and electron transport chain.

Where does glycolysis occur?

In the cell's cytosol.

What molecule is produced from glucose during glycolysis?

Pyruvic acid.

Where does the citric acid cycle take place?

In the mitochondria's matrix.

What does the citric acid cycle produce?

Carbon dioxide, ATP, NADH, and FADH2.

Where does the electron transport chain occur?

In the inner membranes (cristae) of the mitochondria.

What do NADH and FADH2 do in the electron transport chain?

They transport electrons to synthesize ATP.

What happens to oxygen in the electron transport chain?

It combines with electrons and hydrogen atoms to produce water.

What is the role of heat released during cellular respiration?

It helps maintain an organism's temperature for proper enzymatic and metabolic functions.

How does cellular respiration relate to photosynthesis?

The reactants of one process are the products of the other.

What happens to the energy stored in glucose during cellular respiration?

Some is stored as ATP, and the rest is released as heat.

What is the significance of ATP in cellular respiration?

It serves as a source of usable energy for various cellular processes.

What is the overall equation for photosynthesis?

6 CO2 + 6 H2O → C6H12O6 + 6 O2

What are the main products of photosynthesis?

Glucose (C6H12O6) and Oxygen (O2)

What process do organisms use to break down glucose for energy?

Cellular respiration

What is the overall equation for cellular respiration?

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O

How do photosynthesis and cellular respiration relate to each other?

The products of photosynthesis are used in cellular respiration, and the products of cellular respiration are used in photosynthesis.

Can cellular respiration occur without oxygen?

Yes, it can occur anaerobically (without oxygen) or aerobically (with oxygen).

What is anaerobic respiration?

A process that allows organisms to release energy from food without using oxygen.

What are the two processes that allow anaerobic respiration?

Anaerobic respiration and fermentation.

What is alcohol fermentation?

A process where carbohydrates are broken down to release energy, producing ethanol and carbon dioxide.

Which organisms commonly use alcohol fermentation?

Yeasts and some bacteria.

What is lactic acid fermentation?

A process that produces lactate from carbohydrates during energy release.

When does lactic acid fermentation occur in animals?

During intense physical activity when oxygen is limited.

What are facultative anaerobes?

Organisms that can switch between aerobic respiration and anaerobic processes based on oxygen availability.

What are obligate anaerobes?

Organisms that can only live in environments without oxygen, as oxygen is toxic to them.

What are producers in an ecosystem?

Autotrophs that make their own organic food molecules from inorganic sources.

What are consumers in an ecosystem?

Heterotrophs that cannot make their own food and must eat other organisms for energy.

What is the role of herbivores in an ecosystem?

They consume photosynthetic producers for energy and nutrients.

What are omnivores?

Organisms that feed on both producers and other consumers.

What are carnivores?

Predatory organisms that kill and eat other consumers.

What are detritivores?

Organisms that feed on detritus, breaking down dead organic matter into smaller particles.

What are decomposers?

Organisms that chemically break down organic matter.

What is the significance of the cycling of oxygen and carbon dioxide?

It allows for life on Earth to exist as we know it.

What is the role of methanogens in anaerobic respiration?

They help break down complex carbohydrates in ruminants' diets and produce methane.

What is the main energy source for cellular respiration?

Glucose (C6H12O6)

What happens during fermentation in the absence of oxygen?

Only glycolysis occurs to release energy from food.

What is produced during lactic acid fermentation?

Lactate

What type of fermentation is used in the production of yogurt?

Lactic acid fermentation

What role do decomposers play in ecosystems?

Decomposers chemically break down organic matter and recycle nutrients.

Which organisms are considered decomposers?

Fungi and bacteria.

What is the primary source of energy for most food chains?

The sun.

What is a food chain?

A linear sequence showing how energy and matter transfer from one organism to another.

What do the arrows in a food chain represent?

The direction of energy and matter flow from one organism to another.

What is a trophic level?

The position of an organism in a food chain, determined by the number of steps from the start.

What is the first trophic level in a food chain?

Producers, which typically use sunlight to make organic food molecules.

What are primary consumers?

Organisms that eat producers, usually herbivores, found at trophic level 2.

What are secondary consumers?

Organisms that eat primary consumers, usually omnivores or carnivores, found at trophic level 3.

What are tertiary consumers?

Organisms that eat secondary consumers, typically carnivores, found at trophic level 4.

What is the maximum number of trophic levels typically found in terrestrial ecosystems?

Five trophic levels.

How do food webs differ from food chains?

Food webs model complex feeding interactions, showing multiple connections between organisms.

What do food webs illustrate?

The network of feeding interactions through which energy and matter move in an ecosystem.

What is production in ecosystems?

The rate at which chemical energy is stored in organic molecules by living organisms.

What is the role of autotrophs in ecosystems?

They form the base of food chains and webs by capturing energy from sunlight or chemicals.

What happens to energy as it moves through trophic levels?

Some energy dissipates as heat, limiting the number of trophic levels that can be supported.

What is the significance of decomposers in nutrient cycling?

They release nutrients back into the ecosystem by breaking down organic matter.

What are the primary producers in Arctic ecosystems?

Phytoplankton and ice algae.

What do zooplankton eat?

Phytoplankton; they are primary consumers.

What is an example of a tertiary consumer in the Arctic food chain?

Polar bears.

What is a quaternary consumer?

Carnivores that eat tertiary consumers, found at higher trophic levels.

How do seabirds fit into the food web?

They can eat both primary and secondary consumers.

What is the impact of producer abundance on ecosystems?

It influences how energy and matter move through the ecosystem.

What is the role of nutrients released by decomposers?

They serve as building blocks for primary producers.

How can food chains cross between ecosystems?

Organisms like seabirds can feed in one ecosystem and be preyed upon in another.

What is the relationship between energy flow and matter recycling in ecosystems?

Energy flows in one direction while matter is recycled through decomposers.

What is primary production?

The rate at which chemical energy is stored in organic molecules by living organisms.

What are the two categories of primary production?

Gross primary production (GPP) and net primary production (NPP).

What does gross primary production (GPP) measure?

The total amount of chemical energy that producers store over time in a specific area.

What is net primary production (NPP)?

Gross primary production minus the amount of energy used by producers for cellular respiration.

How is NPP used by plants?

For growth and reproduction, including the development of stems, leaves, roots, and fruits.

What does NPP represent in an ecosystem?

The chemical energy available to organisms in the next trophic level, such as consumers.

What does a global map of net primary production show?

Areas of higher plant growth and carbon fixation, indicated by dark green regions.

What is trophic efficiency?

The amount of energy transferred from one trophic level to the next, typically around 10%.

What is the '10% rule' in ecology?

Only about 10% of the total energy available at a trophic level is transferred to the next level.

What limits the number of trophic levels in a food chain?

Trophic efficiency, as there is not enough energy available to support populations at higher levels.

What are the three types of ecological pyramids?

Energy pyramids, biomass pyramids, and numbers pyramids.

What does an energy pyramid show?

The amount of energy available at each trophic level and how trophic efficiency results in less energy at higher levels.

What units are used in energy pyramids?

Kilocalories per square meter per year (kcal/m²/yr).

What does a biomass pyramid measure?

The amount of biomass (mass of living organisms) at each trophic level.

What units are used in biomass pyramids?

Grams per square meter (g/m²).

What does a numbers pyramid show?

The number of organisms at each trophic level.

Why can a numbers pyramid appear inverted?

A small number of producers can support many organisms at higher trophic levels.

What is bottom-up control in community structure?

Organism abundance at each trophic level is limited by nutrients or food availability at lower levels.

What is top-down control in community structure?

Organism abundance at each trophic level is controlled by consumer abundance at higher levels.

How does nutrient supply affect plant abundance?

Low nutrient supply leads to fewer plants, which affects the number of primary consumers and higher trophic levels.

What happens when there are fewer herbivores in an ecosystem?

More plants can grow due to reduced grazing pressure from herbivores.

What is the significance of ecological pyramids?

They model energy loss and the distribution of energy, biomass, or organisms across trophic levels.

How is energy represented in ecological diagrams?

Energy is often represented in joules, illustrating the energy available at each trophic level.

What is the role of phytoplankton in an Arctic ecosystem?

Phytoplankton are producers that use sunlight to produce organic molecules, forming the base of the food chain.

What is the relationship between cellular respiration and energy loss?

Much of the energy from producers is lost to heat and waste during cellular respiration.

What is the significance of the dark blue patches on ocean maps?

They indicate areas of high phytoplankton growth, signifying high production.