Chemical Bonding
What subatomic particles make up an atom?
Protons, neutrons, and electrons.
What is the monomer of a protein?
Amino acid
What is the monomer of a nucleic acid?
Nucleotides
What is the monomer of carbohydrates?
Monosaccharides
What is the monomer of lipids?
Lipids don't have monomers in the traditional sense because a lipid is not a polymer. They are made up of fatty acids and glycerol.
What makes water a good “solvent” (a liquid able to dissolve other molecules)?
Water molecules have a polar arrangement of oxygen and hydrogen atoms—one side (hydrogen) has a positive electrical charge and the other side (oxygen) had a negative charge. This allows the water molecule to become attracted to many other different types of molecules.
How is a single alpha-helix stabilized? What kinds of chemical bonds help keep the alpha-helix
intact?
Each α-helix is stabilized by numerous hydrogen bonds between the components of the peptide bond group. At every location where there is a peptide bond (connecting two amino acids), the C=O group will be “sticking up” towards the next turn of the helix,
precisely where an N-H group will be “sticking down” above it. You might think of this as a very long spiral staircase in which each step is able to form a connection with the step directly above it and directly below it. Stabilization of a single α-helix involves
secondary structure.
What are the three components of the nucleic acid structure?
Nitrogenous base, phosphate, 5-carbon sugar
What is the difference between endocytosis and exocytosis?
Endocytosis involves a cell taking in substances from its surroundings, while exocytosis involves a cell releasing substances to its surroundings.
Why is the amphipathic nature of lipids important for their function in membranes?
This dual nature drives them to organize in aqueous environments, with the hydrophobic tails clustering together and the hydrophilic heads interacting with the surrounding water.
What are the main chemical bonds in biology?
In biology, the main types of chemical bonds are ionic bonds, covalent bonds, hydrogen bonds, and van der Waals forces.
What would determine if a Beta-sheet was hydrophilic or hydrophobic?
Which R-groups are present on the amino acids that make up the sheet. If they are mostly polar or charged, the sheet is likely to be hydrophilic. If they are mostly non-polar, the sheet is likely to be hydrophobic
How can you tell if a molecule is DNA or RNA?
You can tell by looking at the functional groups surrounding the 2’ carbon in the sugar molecule.
A hydroxyl (-OH) group indicates RNA. A hydrogen indicates DNA.
What properties of carbon make it a good backbone for building large biological
molecules?
Carbon is well-suited to be the backbone of large biological molecules due to its ability to form four strong covalent bonds with other atoms, including itself.
What chemical properties would allow a molecule to cross a lipid bilayer?
Specifically, small, nonpolar molecules and small, uncharged polar molecules can readily diffuse through the phospholipid bilayer.
How are polar and non-polar covalent bonds related to a molecule being hydrophilic or
hydrophobic?
Polar covalent bonds tend to make molecules hydrophilic, meaning they dissolve in water, while non-polar covalent bonds tend to make molecules hydrophobic, meaning they do not dissolve in water.
How is a single Beta-sheet held together? What kinds of chemical bonds help keep the Beta-
sheet intact?
Each β-sheet is stabilized by numerous hydrogen bonds between peptide bond groups on one strand of the sheet and peptide bond groups on the adjacent strand of the sheet. The C=O groups will be “pointing towards” the next strand of the sheet, precisely where an N-H group will be “pointing back” toward the
C=O group. Stabilization of a single β-sheet involves secondary structure.
By what mechanism would polymerization occur?
Dehydration synthesis
Compare and contrast prokaryotic and eukaryotic cells. What features do they share in
common, and how do they differ?
Prokaryotic and eukaryotic cells share a plasma membrane, cytoplasm, and ribosomes, but eukaryotic cells are generally larger, have a membrane-bound nucleus, and other membrane-bound organelles for compartmentalized functions. Prokaryotic cells, on the other hand, lack a nucleus and membrane-bound organelles, making them simpler and smaller.
How are the concepts of passive transport and dynamic equilibrium related?
Passive transport is the movement of molecules across a cell membrane from an area of high concentration to an area of low concentration, without requiring energy. Dynamic equilibrium is the state where the concentration of a substance is uniform throughout a space, and while molecules continue to move, there is no net change in concentration over time.
What structural features would most likely make a molecule hydrophilic and/or hydrophobic.
Molecules tend to be hydrophilic (water-loving) if they have polar or charged groups like -OH, -NH2, or -COOH, or if they are ionic. Conversely, molecules are hydrophobic (water-fearing) if they are primarily non-polar, like hydrocarbons.
Why is the 3D shape of a protein so important? Why is it important to be different from other shapes?
The protein shape will depend on which types of amino acids are in their peptide chains, and in which order the amino acids are present. This nearly endless
variety of amino acid chains (primary structures) results in thousands of different proteins in cells, each with their own unique 3D shape and function.
How is the DNA double-helix held together? How do the terms complementary and antiparallel come into play here?
The DNA double helix is held together by hydrogen bonds between complementary base pairs and structured antiparallel, meaning the two strands run in opposite directions.
What are the different parts of the endomembrane system? What role does each play?
The endomembrane system is a network of interconnected membranes in eukaryotic cells that modifies, transports, and packages proteins and lipids. Key components include the nuclear envelope, endoplasmic reticulum (ER), Golgi apparatus, lysosomes, and vesicles.
What is membrane fluidity, and why is it important? How does saturated and unsaturated fatty acids effect membrane fluidity?
Membrane fluidity describes the ability of components (like lipids and proteins) within a cell membrane to move and shift within the two-dimensional lipid bilayer. Saturated fatty acids decrease membrane fluidity, while unsaturated fatty acids increase membrane fluidity.