Molecules of Life Flashcards

Flashcards about Molecules of life: covering elements, compounds, macromolecules, carbohydrates, lipids, proteins, nucleic acids, and water properties.

What are elements?

Substances that cannot be broken down into other substances by chemical reactions, made up of the same type of atoms.

Give examples of elements.

Gold (Au), copper (Cu), carbon (C), and oxygen (O).

What are compounds?

Substances consisting of two or more elements combined in a fixed ratio.

Give examples of compounds.

Sodium chloride (NaCl), H2SO4, MgCl2

What are the essential elements of life and their percentage in living matter?

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

What are trace elements?

Elements required by an organism in low quantities.

What are organic molecules?

Chemical compounds that contain carbon.

What are hydrocarbons?

Organic molecules consisting of only carbon and hydrogen.

What are macromolecules?

Large complex assemblies, or polymers, made up of small, similar chemical subunits (monomers).

What are the four classes of large biological macromolecules?

Carbohydrates, lipids, proteins, and nucleic acids.

What is dehydration synthesis (condensation)?

The process of forming polymers by linking subunits together, with the removal of a water molecule for every bond formed. Requires energy.

What is hydrolysis?

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

What are carbohydrates?

Molecules containing carbon, hydrogen, and oxygen that have sugar as their subunit and are used for energy storage and structural elements.

What are monosaccharides?

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

Classify monosaccharides.

Location of carbonyl group (aldose or ketose) and number of carbons in the carbon skeleton (trioses, pentoses, hexoses).

What are disaccharides?

Formed when two monosaccharides are joined together by a glycosidic bond through condensation. General formula is C12H22O11.

What are polysaccharides?

Macromolecules made up of long chains of many monosaccharides joined together by glycosidic bonds.

Give examples of polysaccharides.

Starch (energy storage in plants), cellulose (structural building material in plants), and glycogen (energy storage in animals).

What is amylose?

Unbranched helical chain of 200-5000 α-glucose units/molecule that stains deep blue with iodine.

What is amylopectin?

Branched chain of 5000-100000 α-glucose units/molecule that stains red to purple with iodine.

What is glycogen?

Storage polysaccharide found in animals, shorter chain with many side branches (α-1,6-glycosidic bond), insoluble in water.

What is cellulose?

Main component of cell walls, polymer of glucose linked by β-1,4 glycosidic bonds, OH groups form hydrogen bonds with neighboring chains.

What are lipids?

Group of molecules insoluble in water, with basic units of glycerol and fatty acids. Includes triglycerides, phospholipids, and steroids.

Describe triglycerides.

Glycerol (polar) and three fatty acids (non-polar hydrocarbon chain with carboxylic acid group, saturated or unsaturated) linked by ester bonds.

Describe phospholipids.

Glycerol attached to two fatty acids and one phosphate group. The glycerol and phosphate are hydrophilic, while the fatty acids are hydrophobic.

Describe steroids.

Non-polar and insoluble in water, structure of three six-carbon rings joined to a five-carbon ring.

What are proteins?

Composed of one or more long chains, or polypeptides, of amino acids linked by peptide bonds.

What are the functional groups attached to a central carbon atom in an amino acid?

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

What happens to proteins when temperature and pH changes?

Structure can be denatured and disrupted by high temperature or changes in pH, causing loss of 3-dimensional shape and function.

List protein structures.

Primary, secondary, tertiary, and quaternary.

Explain primary structure.

The specific amino acid sequence of a protein.

Explain secondary structure.

Repeated twisting and folding of the amino acid chain by hydrogen bonding into characteristic coils (alpha helix) and pleats (Beta pleated sheet).

Explain tertiary structure.

Final folding and twisting that results in the final three-dimensional shape of a polypeptide shape = globular protein. Help by various bond such as ionic, hydrophobic, hydrogen and disulphide bond.

Explain quaternary structure.

When two or more polypeptide chains associate to form a functional protein.

What are nucleic acids?

Complex molecules containing elements of C, H, O, P, and N. Major types are DNA and RNA.

What are nucleotides?

Building blocks of nucleic acids, consisting of a pentose sugar, phosphate group, and nitrogenous base.

What are major differences between DNA and RNA?

DNA contains deoxyribose sugar, the bases A, T, C, and G and is double-stranded. RNA contains ribose sugar, the bases A, U, C, and G, and is single-stranded.

List purines

Adenine and Guanine

List pyrimidines

Cytosine, Thymine, and Uracil

What are the properties of water?

Cohesion, adhesion, good solvent, low viscosity, high-specific heat capacity, high-latent heat of vaporization, maximum density at 4˚C.

Why is water a polar molecule?

Oxygen atom is more electronegative, attracts the electrons more strongly, giving the oxygen atom two partial negative charges(δ-)

What does cohesion in water lead to?

Surface tension, hydrogen bonds in water face downward causing the water molecules at the surface to cling together

Why is water known as the universal solvent?

Due to its polarity. Polar water molecule attract each other, ions and other polar molecules. Hence can dissolve many ionic compound

What is the benefit of the fact that organisms with a high content of water can maintain a relatively constant internal temperature?

High-specific heat capacity and large number of hydrogen bonds that holds the liquid together, a large input of thermal energy is necessary to break apart water molecules

What is responsible for surface tension?

Cohesion – Attraction to other water molecules

What happens as the temperature of water approaches 0˚C?

the molecules form more hydrogen bonds with each other