Chemistry of the Cell
Define "Valence"
The # of e- needed to stabilize the outermost orbital of an atom.
What are the monomers for proteins?
Amino acids
What is meant by sugars are "hydrates of carbon"?
For every molecule of carbon, there is an equivalent amount of water molecules.
What are the monomers for nucleic acids called? What are their three main components?
Nucleotides; a phosphate group, 5 carbon sugar, and a nitrogenous base
What are nucleosomes made out of?
DNA wrapped around an octamer of histone proteins
In the context of bonds, when is energy used, and when is it released?
Bond formation = Releases energy
What is the name of the bond that forms between two proteins? What do you call the amino acids once the bond is formed?
Peptide bonds, residues
Which type of glycosidic bonds can we break? Which type can we not break?
Our body has enzymes that can break down alpha glycosidic bonds, but not beta glycosidic bonds.
1. DNA has a deoxyribose sugar, while RNA has a ribose sugar
2. DNA has thymine, while RNA has uracil
What are histone "tails"?
Stretches of polypeptides that stick out of the histone protein that is prone to modification
___ reactions forms polymers, and ____ reactions breaks down polymers.
Condensation reactions form polymers, and hydrolysis reactions breaks down polymers.
Why are the shapes of proteins so important?
What is the difference between saturated and unsaturated fatty acids?
Saturated fatty acids have no dbl bonds in their structure --> Packs tightly --> Solid at room temp.
Unsaturated fatty acids have >1 dbl bond --> Packs less tightly --> Liquid at room temp.
Adenine and Thymine: 2 H bonds
Cytosine and Guanine: 3 H bonds
Name the two types of histone modifications
Acetylation: Loosens histones grip on DNA
Methylation: Tightens histones grip on DNA
What are the three properties of water?
1. Polar and cohesive: Electronegativity difference makes H2O polar, and is able to from H bonds
2. Temperature stabilizer: ΔE affects H bonds first
3. Solvent: Dissolves polar molecules
Name all of the interactions that affect protein folding.
1. Disulfide bonds
2. H bonds
3. Ionic bonds
4. Van der Waals/London dispersion forces
5. Hydrophobic interactions
Why aren't lipids considered polymers?
Lipids aren't made of repeated monomeric subunits; they are akin to a rope than a chain.
Which nitrogenous bases are purines, and which are pyridines?
Purines: Adenine and Guanine
Pyrimidines: Cytosine, Thymine, and Uracil
Heterochromatin, chromosome, chromatin fiber, nucleosomes, loops
Nucleosomes --> Chromatin fiber --> Loops --> Heterochromatin --> Chromosome
The hill represents the process of molecules forming lower energy bonds. An initial input of energy is needed to break the bonds of the reactants (push up the hill), and the reaction then proceeds spontaneously to create more stable, lower-energy bonds (ball rolling down the hill).
Describe all four levels of protein folding.
2. Secondary: Folding caused by polypeptide backbone
3. Tertiary: Additional folding due to R group interactions
4. Quaternary: Multiple proteins forming a complex
What are the six main classes of lipids?
1. Fatty acids
2. Triglycerides
3. Phospholipids
4. Glycolipids
5. Steroids
6. Terpenes
What is the full name for a DNA nucleotide that has a adenine as a nitrogenous base?
Why is DNA wrapped around histone proteins?
1. To condense DNA
2. To protect DNA
3. To regulate gene expression