Presentation_ Chemical reactions and enzymes (Revised 2023)

What are chemical reactions characterized by?

Atoms are reorganized into different substances.

What is metabolism?

The sum of all chemical reactions that occur in organisms to maintain life.

What is the basic form of a chemical equation?

Reactants → Products.

What are the reactants in photosynthesis?

6 CO2 + 6 H2O.

What determines the chemical properties of elements?

Electron configuration.

What holds the electrons in an atom?

Electrons occur in energy levels.

How many electrons can the first energy level hold?

2 electrons.

What do atoms 'want' to do with their outer shell electrons?

Fill the outer shell.

What is an ion?

An atom with an electrical charge due to a loss or gain of electrons.

What happens when an atom loses electrons?

It gains a positive charge.

What is the result of atoms sharing outer shell electrons?

The formation of covalent bonds.

What is electronegativity?

An atom's attraction for shared electrons.

What does a polar covalent bond result in?

A molecule with positive and negative ends.

What must be true for a chemical equation to be balanced?

The same number of atoms in the reactants must equal the number in the products.

What is activation energy?

The energy needed to start reactions.

What role do enzymes play in chemical reactions?

They act as catalysts that lower the activation energy.

What binds with enzymes in biochemical reactions?

Substrates.