Biology test review ethyn 12

What is the definition of Exergonic?

Exergonic reactions are chemical processes that release energy, often in the form of heat, and have a negative change in Gibbs free energy.

What is metabolism?

Metabolism refers to all the chemical reactions that occur within a living organism to maintain life, including processes that build up or break down substances for energy and cellular function. Metabolism encompasses catabolism and anabolism.

What is Catabolism?

Catabolism is the set of metabolic pathways that break down molecules into smaller units, releasing energy in the process. Net output of energy.

What is Anabolism?

The reverse of catabolism, combines smaller molecules into larger ones, uses a net input of energy. 

What is the definition of Energy?

The ability to do work

What are the two forms of energy?

Kinetic and Potential

What is Kinetic energy?

The energy in motion, e.g. a ball falling down a hill

What is potential energy?

The stored energy, available but not yet released. Cell transforms potential energy into kinetic energy to do work

What is bond energy?

The energy required for a bond to form or break

What is an endergonic reaction?

A chemical reaction which requires an input of energy for it to happen. Positive change in Gibbs free energy.

What is an exergonic reaction?

Exergonic reactions are chemical processes that release energy, often in the form of heat, and have a negative change in Gibbs free energy.

What is thermodynamics?

The study of energy changes in a system

What is a system defined as in themodynamics?

An organism, group of cells, set of substrates and products

What is an open system?

A system , and it’s surrounding environment, which can exchange matter and energy with each other

Is a biological system an open or closed system?

Open system

What is the first law of themodynamics?

Law of conservation of energy

What does the first law of thermodynamics state?

Energy cannot be created or destroyed, rather transformed from one type to another, and transferred from one object to another

What happens if energy leaves a system?

The exact same amount of energy must enter the surroundings

How does a chemical reaction work?

It moves forward until one of the reactants is used up

What is activation energy?

The amount of energy required for a reaction to startWh

What can reduce the activation energy required?

A catalyst (such as an enzyme)

What happens to the energy released from catabolic reactions?

Used to power anabolic reactions

What does ATP get hydrolised into?

ADP and an inorganic phosphate group

What are coupled reactions?

coupled reactions are biochemical reactions where the energy released from an exergonic reaction (e.g., ATP hydrolysis) is used to drive an endergonic reaction. 

What are redox reactions?

Redox reactions are coupled reactions that are crucial for energy flow within biological systems.

When is a compound considered 'reduced' in a redox reaction?

A compound is reduced when it accepts electrons.

When is a compound considered 'oxidized' in a redox reaction?

A compound is oxidized when it loses electrons.

How do electrons contribute to energy transfer in redox reactions?

Electrons carry energy when they pass from one atom to another. The reduced form of a molecule, having gained electrons, is always at a higher energy level than its oxidized form.

What is 'reducing power'?

'Reducing power' refers to the capacity of electrons to reduce another compound.

What determines the amount of energy an electron carries?

The amount of energy an electron carries depends on the energy level it occupies in the atom donating the electrons.

Are electron carriers consumed during reactions?

No, they’re recycled, and can be used again and again

List the two main electron carriers, and name them

NAD+ (Nicotinamide adenine dinucleotide), FAD (Flavin adenine dinucleotide

What are the oxidized forms of NAD+ and FAD+

NADH and FADH2

How does NAD+ get reduced to NADH?

NAD+ gains 2 electrons, and a hydrogen proton, converting to NADH. NAD+ + 2e- + H+ → NADH

What does the Krebs Cycle produce?

2 ATP, 6 NADH. 2 FADH2

What are the 4 stages of aerobic respiration?

Glycolysis, Pyruvate oxidation, Krebs Cycle, Oxidative phosphorylation

Where does glycolysis take place?

In the cytosol

Where does Pyruvate oxidation take place?

In the mitochondrial matrix (po)

Where does Krebs Cycle take place?

In the mitochondrial matrix (krebs)

Where does oxidative phosphorylation take place?

Inner mitochondrial membrane

Does glycolysis require oxygen to take place?

No

What does glycolysis start and end with?

Starts with glucose, ends with pyruvate.

What does glycolysis net produce per glucose molecule?

2 NADH and 2 ATP

What does Pyruvate oxidation start with and end with?

Starts with pyruvate, ends with Acetyl-CoA

What does pyruvate oxidation produce?

2 NADH Molecules

What does the Krebs cycle produce (per glucose molecule)?

6 NADH, 2 FADH2, 2 ATP

What does Oxidative phosphorylation produce?

32-34 ATP

How many total ATP are produced by Cellular Respiration?

36-38 ATP

How does glycolysis work?

Starts with glucose, 10 steps, a multitude of enzymes act upon it, producing pyruvate.

How does Pyruvate Oxidation work?

Requires oxygen to be present. Carboxyl group stripped from pyruvate (forms carbon dioxide), CoenzymeA attaches to Acetyl group, forms Acetyl-CoA

How does the Krebs cycle work?

Acetyl-CoA and Oxaloacetate combine to form Citrate. Citrate undergoes the Krebs cycle, until it becomes Oxaloacetate. Oxaloacetate reacts with the new Acetyl-CoA, and the cycle starts again. 

How does Oxidative phosphorylation work?

NADH and FADH2 drop electrons and H+ protons into proteins located in the inner mitochondrial membrane. Because of this, an electrochemical gradient is established. The H+ protons are channeled from the inner mitochondrial membrane, into the mitochondrial matrix, via the enzyme ATP Synthase, ADP gets phosphorylated by ATP synthase, into ATP.