Chemistry of Life

What five properties define organisms as “alive”?

• grow

• reproduce

• maintain homeostais

• sense and respond to stimuli

• obtain and use energy

• have levels of internal organization (also important to know)

• made of one or more cells

Atom 

Smallest unit of an element that still has its properties  

What is the nucleus of an atom and what does it contain?

• dense core of an atom

• contains protons and neutrons

When is an atom neutral in charge?

When it has the same number of protons as electrons

What are the subatomic particles?

• protons

• neutrons

• electrons

Atomic Number

Number of protons in an atom (each element on the table is placed by this)

Of the subatomic particles which have significant mass?

Protons and neutrons (because they reside in the nucleus) 

Valence Shell

The outer electron ring of an atom

What happens if the valence shell is unfulfilled?

Its going to be reactive

What makes an element more reactive?

Needs a higher amount of electrons

What makes it easier to pull electrons away from the nucleus?

Electronegativity and how far away they are

Ion

An atom that has gained or lose electrons (giving it a charge)

Covalent Bonds

Strong bond where atoms share a pair of electrons

Ionic Bonds

Bond formed by the transfer of electrons between atoms (results in oppositely charges ions that attract each other)

What defines an inorganic molecule?

No carbon-based backbone or C-H bond

What defines an organic molecule?

Carbon-based backbone with at lease one C-H bond

Macromolecules

Large organic molecules

Monomers

Subunits that make up macromolecules

Polymer Chains

Monomers linked together

What are the four types of macromolecules?

• carbohydrates

• proteins

• lipids

• nucleic acids

Which macromolecule does not have a monomer?

Lipids

What is monomer of carbohydrates?

Simple sugars called monosaccharide/polysaccharides

What is the monomer of proteins?

Amino acids

How many animo acids are commonly used?

20

What makes one amino acid different from another?

Its side chain

Whats true about the main chain of of amino acids?

Its always the same atom

What are lipids made of?

Mostly carbon and hydrogen (hydrocarbon tails)

Do lipids mix with water, why or why not?

No, they are hydrophobic due to the hydrocarbon tails (fulfilled)

What is the monomer of nucleic acids?

Nucleotide 

What are the two types of nucleic acids?

• DNA

• RNA

What are cell membranes made of?

Phospholipid bilayer

Phospholipids

Molecule with a water loving head and a water hating tail

Why is water essential for life?

All life’s chemical reactions take place in water

Why is water poler?

Oxygen pulls electrons more strongly than hydrogen, creating partial charges

What type of bond connects water molecules together?

Hydrogen bonds

Cohesion

Water molecules sticking together due to hydrogen bonding

Adhesion

Water molecules sticked to other surfaces

Solvant

Substance that does the dissolving

• usually the larger amount of a substance

• stays the same

Solute

Substances being dissolved

• usually the smaller amount

• disappears

Water dissolves what kind of molecules and substances?

• other polar molecules

• substances that contain ionic bonds

Why is water’s large liquid range important?

• it stays liquid over a wide range of temps

• useful because our bodies are mostly water

pH

A measure of the concentration of hydrogen ions present

Acidic Solution

• releases H+ ions

• pH less than 7

• sour taste

• corrosive

Basic Solution

• absorbs H+ ions

• pH higher than 7

• bitter

• used in cleaners

Which property of water is most responsible for its amazing properties of adhesion and cohesion?

polar covalent bonds