Cellular processes

What is homeostasis?

The process by which organisms maintain a stable environment.

What is the concentration in a solution?

It measures the amount of solute in the solution.

What is diffusion?

Movement of particles from a highly concentrated area to a less crowded area to reach equilibrium.

What is osmosis?

The diffusion of water through a selectively permeable membrane.

What does hypotonic solution mean?

A solution with a higher concentration inside the cell, causing the cell to grow.

What is isotonic solution?

A solution where the concentration inside the cell matches that outside, resulting in little to no movement.

What does hypertonic solution mean?

A solution with a higher concentration outside the cell, causing the cell to shrink.

What is passive transport?

Movement of molecules across a cell membrane without the use of energy.

What is active transport?

The process of moving molecules against the concentration gradient, using energy.

What is endocytosis?

The process when cells engulf substances from the outside environment.

What is exocytosis?

The process when cells expel material through their membranes.

What is cellular respiration?

It releases energy from glucose and other food molecules in the presence of oxygen.

What is photosynthesis?

The process by which autotrophs convert light energy into the energy of carbohydrates.

What is ATP?

Adenosine triphosphate, a compound used to store/release energy in cells.

What is glycolysis?

The first step in cellular respiration, converting glucose into pyruvate and producing ATP.

What is the citric acid cycle?

A series of reactions that generates ATP, NADH, and FADH2 while releasing carbon dioxide.

What is oxidative phosphorylation?

The final stage of cellular respiration that generates ATP using the electron transport chain.

What is chemiosmosis?

The process by which ATP is synthesized from the proton gradient across a membrane.

What is substrate-level phosphorylation?

A process of generating ATP when a phosphate group is transferred to ADP from another molecule.

What is fermentation?

An anaerobic process that allows organisms to produce ATP without oxygen.

What are obligate anaerobes?

Organisms that can only live and grow in the absence of oxygen.

What are facultative anaerobes?

Organisms that can switch between aerobic respiration and anaerobic pathways depending on oxygen availability.

What happens in cellular respiration?

Glucose is broken down into carbon dioxide and water, releasing energy.

What role do electron carriers play in cellular respiration?

They transport electrons from glucose breakdown to the electron transport chain.

What is NAD+?

A key electron carrier that accepts electrons during metabolic reactions.

What is FAD?

Another important electron carrier that is reduced to FADH2 in metabolic reactions.

Define redox reactions.

Chemical reactions that involve the transfer of electrons between molecules.

What is the function of ATP synthase?

An enzyme that synthesizes ATP from ADP and inorganic phosphate using a proton gradient.

How is energy released in cellular respiration?

Energy is released when electrons move from glucose to oxygen through the electron transport chain.

What are the main products of cellular respiration?

Carbon dioxide, water, and ATP.

What are the reactants of photosynthesis?

Carbon dioxide, water, and sunlight.

What do plants produce during photosynthesis?

Glucose and oxygen.

How does osmosis differ from diffusion?

Osmosis specifically refers to the movement of water across a selectively permeable membrane, while diffusion refers to the movement of any particles.

What occurs during glycolysis?

Glucose is converted into two molecules of pyruvate, producing ATP and NADH.

Where does cellular respiration occur in eukaryotic cells?

Mainly in the mitochondria.

What is produced in alcoholic fermentation?

Ethanol and carbon dioxide.

What is produced in lactic acid fermentation?

Lactic acid.

What is the role of chlorophyll in plants?

To absorb light energy from the sun for photosynthesis.

Which type of cells perform cellular respiration?

All cells, including plants, animals, and microscopic life.

What is the function of the electron transport chain?

To transfer electrons and create a proton gradient for ATP synthesis.

What is the difference between NADH and FADH2?

NADH is produced during glycolysis and the citric acid cycle, while FADH2 is produced in the citric acid cycle and enters the electron transport chain at a lower energy level.

What is ATP's role in cellular processes?

ATP serves as the primary energy carrier in cells.

How does ATP release energy?

By breaking one of its phosphate bonds to form ADP.

What is the net gain of ATP from glycolysis?

2 ATP.

What is the primary function of the citric acid cycle?

To oxidize acetyl CoA and produce NADH, FADH2, and ATP while releasing CO2.

What happens during oxidative phosphorylation?

Electrons from NADH and FADH2 pass through the electron transport chain, driving ATP synthesis via chemiosmosis.

What is the role of oxygen in cellular respiration?

Oxygen acts as the final electron acceptor in the electron transport chain.

What is meant by 'electron transport'?

The movement of electrons through the electron transport chain, generating a proton gradient.

What occurs to the products of cellular respiration?

They are used as reactants for subsequent metabolic processes.

What are the products of the citric acid cycle?

2 ATP, 6 NADH, and 2 FADH2 per glucose molecule.

What serves as the energy source in cellular respiration?

The glucose molecule and other food molecules.

What is anaerobic respiration?

A process of producing ATP without oxygen, often using a different final electron acceptor.

What happens during the pyruvate oxidation stage?

Pyruvate is converted to acetyl CoA, producing CO2 and NADH.

How does temperature affect cell transport processes?

Higher temperatures generally increase the rate of diffusion and osmosis.

What is glycolysis's location in the cell?

It occurs in the cytoplasm.

What do the terms 'oxidized' and 'reduced' mean in the context of redox reactions?

Oxidized refers to a substance that loses electrons, while reduced refers to a substance that gains electrons.

What role do high-energy electrons play in cellular respiration?

They provide energy for ATP synthesis during the electron transport chain.

Describe the ATP yield from one molecule of glucose through cellular respiration.

The total yield is typically about 30-32 ATP.

What must happen for glycolysis to continue in an anaerobic environment?

NADH must be converted back to NAD+.

What happens to excess glucose in the body?

It is stored as glycogen or converted to fat.

What is the primary function of fermentation?

To regenerate NAD+ so glycolysis can continue.

What is the significance of water in cellular respiration?

It is produced as a byproduct when oxygen accepts electrons at the end of the electron transport chain.

What is the primary difference between fermentation and cellular respiration?

Fermentation occurs without oxygen, whereas cellular respiration requires oxygen.

What does the term 'aerobic respiration' imply?

It refers to cellular respiration that requires oxygen.

What do brown fat cells do?

They utilize proton gradients to generate heat instead of ATP during respiration.

How many molecules of CO2 are produced from one glucose molecule in cellular respiration?

6 molecules of CO2.

What are the electron carriers that play crucial roles in cellular respiration?

NAD+ and FAD.

What do 'facultative anaerobes' use when oxygen is present?

Aerobic respiration.

What do 'obligate anaerobes' rely on?

Anaerobic pathways for energy production.

Why is it important for cells to maintain homeostasis?

To ensure stable internal conditions for optimal function.

What is meant by 'gain of electrons' in a redox reaction?

It signifies reduction of a substance.

What is meant by 'loss of electrons' in a redox reaction?

It signifies oxidation of a substance.

Describe the fate of energy in glucose during cellular respiration.

Energy is gradually released during the breakdown of glucose to power ATP synthesis.

What does ATP synthase do?

It catalyzes the formation of ATP from ADP and inorganic phosphate.

What does it mean when phosphorus is bonded in ATP?

It represents stored energy that can be released for cellular work.

What happens to pyruvate in the absence of oxygen?

It undergoes fermentation instead of entering the citric acid cycle.

Define “proton-motive force.”

The electrochemical gradient created by pumping protons across a membrane.

What is the main role of the mitochondria related to energy?

To generate ATP through cellular respiration.

What is the primary result of the electron transport chain?

The creation of a proton gradient used for ATP synthesis.

What happens to electrons at the end of the electron transport chain?

They are transferred to oxygen, forming water.

In what form is energy stored in the body?

As ATP.

What effect does exercise have on muscle cells concerning respiration?

Muscle cells may rely on lactic acid fermentation when oxygen is low.

What are the end products of lactic acid fermentation?

Lactic acid and NAD+.

What do methanogens produce?

Methane as a byproduct of anaerobic respiration.

Why might some prokaryotes use anaerobic cellular respiration?

To generate ATP in environments devoid of oxygen.

When does the citric acid cycle occur?

After pyruvate oxidation in the presence of oxygen.

What happens to FADH2 in the electron transport chain?

It is oxidized, donating electrons to the chain at complex II.

What compound regulates energy in muscle cells during strenuous activity?

Lactic acid.

How does the body handle lactic acid produced in muscles?

It is transported to the liver for conversion back to pyruvate.

What is the overall equation for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP.

Why is oxygen critical in cellular respiration?

It acts as the final electron acceptor, allowing the electron transport chain to function.

What is the fate of pyruvate in alcoholic fermentation?

It is converted to ethanol and carbon dioxide.

What happens when NAD+ levels drop in glycolysis?

Glycolysis slows down or ceases without adequate regeneration.

Define catabolic reactions.

Reactions that break down larger molecules into smaller ones, releasing energy.

How do you know oxygen is used in respiration?

It is required in oxidative phosphorylation and as an electron acceptor.

How many ATP are produced during glycolysis?

2 net ATP are produced.

What role do sulfide-reducing bacteria play in anaerobic environments?

They perform anaerobic respiration using sulfate as a final electron acceptor.

What occurs in anaerobic environments when oxygen is not present?

Fermentation or anaerobic cellular respiration occurs to generate ATP.

What is the relationship of photosynthesis to cellular respiration?

Photosynthesis produces glucose, which is used in cellular respiration to generate ATP.

What is the function of uncoupling proteins in brown fat?

To dissipate the proton gradient as heat instead of producing ATP.