Biochemistry Exam 1

What are the six most abundant elements in biological molecules?

Carbon (C), Hydrogen (H), Nitrogen (N), Oxygen (O), Phosphorus (P), Sulfur (S)

What is an amino acid?

Building blocks of proteins, consisting of an amino group, a carboxyl group, and a side chain (R group).

What are proteins?

Polymers of amino acids that perform a wide range of functions, including catalysis, structure, and regulation.

What is a monosaccharide?

Simple sugars that are the basic units of carbohydrates (e.g., glucose).

What is a polysaccharide?

Long chains of monosaccharides linked by glycosidic bonds (e.g., starch, glycogen).

What is a nucleotide?

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

What are nucleic acids?

Polymers of nucleotides that store and transmit genetic information (e.g., DNA, RNA).

What is the benefit of polymers in macromolecules?

Polymers allow for the creation of large, complex molecules with diverse functions from a limited set of monomers.

What are amphipathic molecules?

Molecules that have both hydrophilic and hydrophobic regions, allowing them to form structures like cell membranes.

What are oxidation and reduction?

Oxidation is the loss of electrons; reduction is the gain of electrons.

What is the difference between endergonic and exergonic reactions?

Endergonic reactions require energy input (positive ΔG), while exergonic reactions release energy (negative ΔG).

How can the age of Earth be determined?

Using radiometric dating techniques.

What are the three domains of life?

Bacteria, Archaea, and Eukarya.

What is enthalpy?

Total heat content of a system.

What is entropy?

Measure of disorder or randomness in a system.

What does ΔG represent?

The value of ΔG indicates whether a biochemical process is spontaneous (negative ΔG) or requires energy input (positive ΔG).

How can thermodynamically unfavorable reactions proceed in vivo?

By coupling them with favorable reactions, often using ATP hydrolysis.

What is the polar nature of water?

Water is a polar molecule with a partial positive charge on hydrogen atoms and a partial negative charge on the oxygen atom.

What is the significance of hydrogen bonding in water?

Hydrogen bonds form between water molecules, contributing to water's unique properties.

What defines amphipathic molecules?

A molecule can be both hydrophilic and hydrophobic, known as amphipathic.

What does the pK value indicate?

The pK value indicates a molecule's tendency to lose a proton; a lower pK means a stronger acid.

What is the relationship between pH and pK?

The pH at which an acid is half dissociated is equal to its pK.

What is a buffer solution?

A solution of a weak acid and its conjugate base that minimizes pH changes.

When is a buffer most effective?

A buffer is most effective within ±1 pH unit of its pK.

What is the Henderson-Hasselbalch equation used for?

To understand terms related to respiratory/metabolic acidosis and alkalosis.

What is dideoxy DNA sequencing?

A method using chain-terminating nucleotides to determine DNA sequences.

What is PCR?

Polymerase Chain Reaction amplifies DNA segments using specific primers and DNA polymerase.

What are NTPs and dNTPs?

NTPs are nucleoside triphosphates for RNA; dNTPs are deoxynucleoside triphosphates for DNA.

What is the role of chaperones?

Chaperones assist in the proper folding of proteins and prevent misfolding.

What are recombinant proteins?

Proteins produced by inserting a gene of interest into an expression system and purifying it.

How does myoglobin differ from hemoglobin?

Myoglobin has a higher affinity for O2 than hemoglobin, allowing it to store oxygen in muscles.

What is the Bohr effect?

It describes how pH and CO2 levels affect hemoglobin's O2 affinity.

What is sickle cell anemia?

A genetic disorder caused by a mutation in the hemoglobin gene, leading to abnormal hemoglobin structure.

What are protein purification techniques?

Techniques such as affinity chromatography, ion exchange chromatography, and size-exclusion chromatography.

What is microfilament polarity?

Microfilaments have polarity due to the orientation of actin monomers, affecting their growth.

What are microtubules involved in?

Cell division and intracellular transport.

What is the function of collagen and keratin?

Collagen provides tensile strength in connective tissues, while keratin provides structural support in hair, nails, and skin.

What is the myosin-actin reaction cycle?

Includes steps such as myosin binding to actin, power stroke, and myosin detachment.

What is kinesin's role as a motor protein?

Kinesin moves along microtubules in a hand-over-hand manner to transport cargo.

What is the role of Vitamin C?

Essential for collagen synthesis and acts as an antioxidant for humans.

What is size-exclusion chromatography?

A technique that separates proteins based on size.

What is ion-exchange chromatography?

A technique that separates proteins based on charge.

What is Edman degradation?

A process that sequentially removes amino acids from the N-terminus of a protein for sequencing.