What is the general chemical formula for carbohydrates?
C(H2O)
What is a monosaccharide?
A simple sugar.
What is a disaccharide?
A carbohydrate composed of two monosaccharides.
What is a polysaccharide?
A long carbohydrate polymer formed of many monosaccharides linked together.
What is the structural difference between ⍺-glucose and β-glucose?
In ⍺-glucose the hydroxyl (-OH) group is point downward while the β-glucose hydroxyl is pointed upward.
Why are the differences between ⍺-glucose and β-glucose biologically significant?
⍺-glucose forms starch/glycogen (digestible for energy), β-glucose forms cellulose (structural, indigestible by humans)
How do the storage forms of glucose differ in plants (starch) and animals
(glycogen) in terms of branching and biological function?
Glycogen in animals is a more highly branched polysaccharide than starch in plants.
Why are lipids considered hydrophobic? How does their structure explain this
property?
Lipids are hydrophobic because molecularly they are not polar and therefore insoluble in water.
What is the structure and biological role of fat?
Structure: triglyceride. Role: energy storage, insulation, organ protection, and forming cell membranes.
What is the structure and biological role of phospholipids?
Structure: amphipathic. Role: forming the lipid bilayer of all cell membranes, providing a fundamental barrier for a cell’s interior and exterior.
What is the structure and biological role of steroids?
Structure: four-ring carbon skeleton. Role: signaling molecules that regulate a wide range of physiological processes and serve as key structural components of cell membranes.
What is saturated fatty acids?
Fats with single bonds between every carbon atom in their hydrocarbon chain. Usually solid at room temperature.
What is unsaturated fatty acids?
Fats containing at least one carbon-carbon double bond in their carbon chain. Usually liquid at room temperature.
Why do cis double bonds in unsaturated fatty acids introduce “kinks” into hydrocarbon chains?
The rigid, double bond prevents free rotation and forces the hydrocarbon chains to bend at a 30-degree angle.
What are the three subatomic particles of an atom, and where are they located?
Protons, neutrons, and electrons. Protons and neutrons are located in the atom’s nucleus, while electrons are found in the electron cloud.
How do atomic number and mass number differ?
Atomic Number: # of protons. Mass Number: # of protons and neutrons.
What is a covalent bond?
A chemical bond where two atoms share a pair of electrons (creates a more stable molecule).
What is an ionic bond?
A chemical bond where one atom transfers one or more electrons to another atom.
What determines whether a covalent bond is polar or nonpolar?
In a polar covalent bond the electron(s) is transferred. In a non polar covalent bond the electron(s) are shared.
What is a hydrogen bond?
A weak attraction between a hydrogen atom and a highly electronegative atom (like oxygen or nitrogen).
Why is a hydrogen bond weaker than a covalent bond?
Hydrogen bonds do not involve the sharing of electrons, therefore easier to break.
Why is water considered the “solvent of life”
Its polar molecular structure allows it to dissolve a wide range of substances.
What properties of water result from hydrogen bonding?
Cohesion, adhesion, high boiling point, high heat capacity, and strong surface tension.
What is an acid?
A substance that can donate a proton, accept electrons, or increase the hydrogen ion concentration in an aqueous solution. Has a pH < 7.
