BSC114 Exam 2

What is kinetic energy?

The energy of movement, applicable to atoms and molecules, contributing to thermal energy.

Define potential energy.

Energy stored due to an object's position, such as in chemical bonds.

What is thermal energy?

Kinetic energy associated with the random movement of atoms or molecules, often lost as heat in biological systems.

What is chemical energy?

Energy stored in chemical bonds, crucial for metabolic reactions.

How does potential energy relate to kinetic energy?

Potential energy can turn into kinetic energy when something is in motion.

What does the first law of thermodynamics state?

Energy cannot be created or destroyed, only transformed.

What is the second law of thermodynamics?

Every energy transfer increases the entropy of the universe, indicating that energy transformations are not 100% efficient.

What is free energy?

The portion of a system's energy available for conversion to work, crucial for predicting reaction spontaneity.

What does a negative free energy change (ΔG) indicate?

A spontaneous reaction that releases energy.

What is energy coupling?

The interaction between catabolic and anabolic pathways, where energy released from catabolism drives anabolic reactions.

What is ATP and its role in cells?

ATP is a nucleotide that serves as the primary energy carrier in cells, storing energy in high-energy bonds between phosphate groups.

What happens during ATP hydrolysis?

ATP is converted to ADP and inorganic phosphate, releasing energy for cellular work.

How is ATP regenerated?

ATP can be regenerated from ADP through the addition of a phosphate group.

What are enzymes?

Biological catalysts that accelerate chemical reactions without being consumed, lowering the activation energy required.

What is the lock and key mechanism in enzyme action?

Enzymes bind substrates at their active sites, leading to a change in the enzyme's shape that facilitates the chemical reaction.

What is feedback inhibition?

A regulatory mechanism where the end product of a pathway inhibits an earlier step, often through allosteric regulation.

What are competitive and non-competitive inhibitors?

Competitive inhibitors resemble substrates and compete for the active site, while non-competitive inhibitors bind elsewhere, altering enzyme function.

What is oxidation in metabolic reactions?

The loss of electrons during a reaction.

What is reduction in metabolic reactions?

The gain of electrons during a reaction.

Where does glycolysis occur in eukaryotes?

In the cytoplasm.

Where does the citric acid cycle occur in eukaryotes?

In the mitochondria.

Where does the electron transport chain reside in eukaryotes?

In the inner mitochondrial membrane.

What are NAD+ and FAD in cellular respiration?

Important electron carriers that facilitate the transfer of electrons during metabolic reactions.

What is the significance of the ATP cycle?

It allows for a continuous energy supply in cells, with ATP being recycled rapidly.

What conditions affect enzyme function?

Enzymes have optimal conditions (temperature, pH, salt concentration) under which they perform best; deviations can lead to decreased activity or denaturation.

What are cofactors?

Metal ions or organic molecules (coenzymes) required for enzyme activity, enhancing their catalytic capabilities.

What is glycolysis?

The breakdown of glucose into 2 pyruvate molecules, producing a net gain of 2 ATP and 2 NADH.

Where does glycolysis occur?

In the cytoplasm.

What are the three phases of glycolysis?

Preparatory phase, cleavage phase, and payoff phase.

What occurs during the preparatory phase of glycolysis?

2 ATP are consumed to convert glucose into fructose 1,6-bisphosphate.

What happens during the cleavage phase of glycolysis?

Fructose 1,6-bisphosphate is split into two 3-carbon molecules.

What is produced during the payoff phase of glycolysis?

4 ATP and 2 NADH, resulting in a net gain of 2 ATP per glucose molecule.

What is pyruvate oxidation?

The conversion of pyruvate into acetyl-CoA while releasing CO2 and generating NADH.

Where does the citric acid cycle (Krebs cycle) occur?

In the mitochondria.

What does acetyl-CoA combine with to enter the citric acid cycle?

Oxaloacetate to form citrate.

What are the products of one turn of the citric acid cycle?

1 ATP, 3 NADH, 1 FADH2, and 2 CO2 as waste products.

What is oxidative phosphorylation?

The process that occurs in the inner mitochondrial membrane, producing the majority of ATP through the electron transport chain (ETC).

What is the role of the proton gradient in ATP synthesis?

It drives ATP synthesis from ADP and inorganic phosphate (Pi) through chemiosmosis.

What is substrate-level phosphorylation?

ATP production occurring during glycolysis and the citric acid cycle through direct transfer.

What is fermentation?

A process that allows glycolysis to continue in the absence of oxygen by regenerating NAD+ from NADH.

What are the two types of fermentation?

Lactic acid fermentation and alcoholic fermentation.

What is the overall equation for photosynthesis?

6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

Where does photosynthesis occur?

In chloroplasts.

What is the primary pigment involved in photosynthesis?

Chlorophyll.

What is the function of thylakoid membranes?

They are where the light reactions of photosynthesis take place.

What is the stroma in chloroplasts?

The fluid-filled space where the Calvin Cycle occurs.

What are photoautotrophs?

Organisms that use light energy to synthesize organic compounds, such as plants and algae.

What are heterotrophs?

Organisms that cannot produce their own food and rely on consuming other organisms.

What are carotenoids?

Accessory pigments that protect chlorophyll from damage by absorbing excess light.

What is the role of ATP synthase?

It synthesizes ATP using the energy from the proton gradient created by the electron transport chain.

What is the primary function of chloroplasts?

To house chlorophyll, the green pigment essential for capturing light energy.

What are the three membranes of a chloroplast?

Outer membrane, inner membrane, and thylakoid membrane.

What happens when a photon hits an electron in an atom?

It can transfer energy to the electron, causing it to jump to a higher energy level, a process known as excitation.

Where do light reactions of photosynthesis occur?

In the thylakoid membranes.

What do light reactions convert solar energy into?

Chemical energy in the form of ATP and NADPH.

What is released as a byproduct when water is split during light reactions?

Oxygen (O2).

What is the Calvin cycle primarily responsible for?

Converting CO2 into glucose using ATP and NADPH.

What enzyme is primarily used in carbon fixation during the Calvin cycle?

Rubisco.

What are the main types of photosynthetic organisms besides plants?

Algae, euglena, cyanobacteria, and purple sulfur bacteria.

What is photorespiration?

A process where rubisco adds oxygen instead of CO2 to ribulose biphosphate, reducing photosynthetic efficiency.

How do C4 plants minimize water loss?

By using a 4-C intermediate for CO2 fixation.

What is the difference in stomata behavior between C3 and CAM plants?

C3 plants open stomata during the day, while CAM plants open them at night.

What is metabolism?

All the chemical changes that occur in an organism.

What are catabolic pathways?

Pathways that break down complex molecules into simpler compounds.

What is the role of competitive inhibitors?

They compete with substrates for the active site of enzymes.

What is cellular respiration?

The process by which cells convert glucose and oxygen into energy (ATP), CO2, and water.

What is the end product of glycolysis?

Pyruvate.

What is the chemiosmotic hypothesis?

The proposal that ATP synthesis is driven by a proton gradient across the mitochondrial membrane.

What role does rubisco play in photosynthesis?

It catalyzes the first step of the Calvin cycle, incorporating CO2 into organic molecules.

What is the equation for photosynthesis?

6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

What is the equation for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP.