Chapter 6: Energy, Cells and Biological Reactions

These flashcards cover key concepts, definitions, and processes related to energy, enzymes, and biological reactions as discussed in Chapter 6.

What is energy defined as in biology?

The ability to do work or move matter.

What are the two types of energy mentioned?

Potential energy (stored energy, available to do work) and Kinetic energy (energy being used to do work).

How do we measure energy?

In calories, which is the amount of energy needed to raise the temperature of water by 1 degree, and kilocalories, where 1 kcal = 1000 calories.

What is the first law of thermodynamics?

Energy is not created or destroyed, only converted.

What is the second law of thermodynamics?

Every reaction loses some energy to the environment in the form of heat.

What is entropy?

The measure of randomness or disorganization.

What is metabolism?

All of the chemical reactions in a cell, including building and breaking down molecules.

What characterizes an endergonic reaction?

It requires the input of energy to proceed, resulting in products that contain more energy than the reactants.

What characterizes an exergonic reaction?

It releases energy, resulting in products that contain less energy than the reactants.

What role do electrons play in chemical reactions?

Electrons carry energy throughout reactions, with oxidation involving the loss of electrons and reduction involving the gain of electrons.

What is ATP?

Adenosine triphosphate, which stores much of the cell's energy.

What is the hydrolysis reaction of ATP?

ATP + H2O results in ADP + P + Energy.

How are coupled reactions related to ATP?

Exergonic reactions supply energy for ATP production, while ATP synthesis is an endergonic reaction.

What is an enzyme?

An organic molecule (proteins) that catalyzes reactions without being consumed.

What are two ways enzymes work?

By lowering activation energy and bringing reactants into contact with each other.

What factors can affect enzyme activity?

Temperature and pH.

What are some examples of enzymes that break down fruit juices?

Pineapple contains bromelain, kiwi has actinidin, papaya contains papain, figs contain ficain, and mango has actinidain.

What is lactose intolerance related to?

Missing lactase, the enzyme required to break down lactose.

What is a negative feedback loop in relation to enzyme regulation?

It regulates chemical reactions by mechanisms such as non-competitive and competitive inhibition.