Molecules of Life Flashcards

Flashcards based on Molecules of Life lecture notes.

Define an element in the context of chemistry.

A substance that cannot be broken down into other substances by chemical reactions and is made up of the same type of atoms.

Give examples of elements that can exist as molecules.

H2, O2, N2, F2, I2, Cl2, Br2

What is a compound?

A substance that consists of two or more elements combined in a fixed ratio, such as sodium chloride (NaCl).

List the main elements essential for life and their combined percentage in living matter.

Carbon, hydrogen, oxygen, and nitrogen (C, H, O, N) which make up 96-98.5% of living matter.

Define organic molecules.

Chemical compounds that contain carbon.

What are hydrocarbons?

Organic molecules consisting of only carbon and hydrogen.

Name the four classes of large biological macromolecules.

Carbohydrates, lipids, proteins, and nucleic acids.

What are monomers?

Small, similar chemical subunits that link together to form larger molecules (polymers).

Describe dehydration synthesis (condensation).

The process of linking subunits together by removing a water molecule for every bond formed; it requires energy.

Describe hydrolysis.

The reverse of dehydration synthesis, breaking the bond between subunits by consuming a water molecule and releasing stored energy.

List the functions of carbohydrates.

Energy-storage molecules and structural elements.

What are monosaccharides?

Simplest carbohydrates with 3-7 carbon atoms, having molecular formulas that are usually multiples of CH2O (e.g., glucose).

How are monosaccharides classified?

By the location of the carbonyl group (aldose or ketose) and the number of carbon atoms in the carbon skeleton (trioses, pentoses, hexoses).

What is glycosidic bond?

Two monosaccharides are joined together by glycosidic bond through condensation

List the types of disaccharides.

Maltose, sucrose, lactose.

Polysaccharides are long chains of many joined together by __ bonds.

monosaccharides, glycosidic

Give examples of polysaccharides.

Starch, cellulose, and glycogen.

What is the functions of lipids .

Insoluble in water, includes triglycerides (oil and fats), phospholipids and steroids.

Describe the structure of a triglyceride.

Glycerol is polar (C3H8O3) with each fatty acid consisting of a non-polar hydrocarbon chain with a carboxylic acid group (COOH) at one end.

Describe phospholipids.

Made up of glycerol, two fatty acids, and a phosphate group; they form the core of all biological membranes with a hydrophilic head and hydrophobic tail.

What is the basic structure of steroids?

Three six-carbon rings joined to a five-carbon ring; they are nonpolar and insoluble in water.

What are proteins composed of?

One or more long chains, or polypeptides, composed of amino acids linked by peptide bonds.

List the three important functional groups attached to a central carbon atom in each amino acid.

Amino group (-NH2), a carboxyl group (-COOH), and an R group (a side chain).

Name the four levels of protein structure.

Primary, secondary, tertiary, and quaternary structure.

What is denaturation and renaturation?

Denaturation is when a protein loses its 3-dimensional shape and function, while renaturation is when a protein refolds and regains its original shape.

Name the elements present in nucleic acids.

Carbon, hydrogen, oxygen, phosphorus, and nitrogen.

List the two major types of nucleic acids.

Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

What are the three components of a nucleotide?

Pentose sugar, phosphate group, and nitrogenous base.

What sugar does DNA contain?

Deoxyribose

What sugar does RNA contain?

Ribose

How does water benefit reproduction and organism growth?

Water covers 75% of the Earth, comprises 2/3 of an organism’s body, and is essential for reproduction and organism growth.

What properties make water a polar molecule?

Oxygen and hydrogen atoms attract electrons shared in covalent bonds (electronegativity), giving the oxygen atom two partial negative charges (δ-).

A water molecule is hydrogen-bonded to _ others.

Four

Describe cohesion and adhesion in water.

Cohesion: water molecules held together by hydrogen bonds. Adhesion: water molecules attracted to other molecules. Cohesion leads to surface tension.

What is meant by water's high specific heat capacity?

A large input of thermal energy is necessary to break apart water molecules in a liquid. This allows water to absorb or lose large amounts of heat without large changes in temperature.

What is meant by water's high latent heat of vaporization?

It requires high energy to change its state from liquid to vapor such that evaporation of water from a surface causes cooling of the surface.

Explain why water had maximum density at 4 degrees C.

Movement of molecules slows down and they move closer to one another as the temperature of water decreases, increasing its density until it reaches 4˚C.