Cell Molecular Exam 1 Flashcards
(37 cards)
What are the four main biological macromolecules? What is the individual subunit (monomer) that makes up each?
Polysaccharide (monomer: monosaccharides)
Proteins (monomer: amino acids)
Nucleic acids (monomer: nucleotides)
Lipids (monomer: fatty acids).
What is the role of ATP in the cell? How does the ATP molecule store energy?
ATP serves as the primary energy currency of the cell.
Storing energy in its high-energy phosphate bonds.
Compare and contrast prokaryotic and eukaryotic cells.
Prokaryotic cells are unicellular, lack a nucleus, and have no membrane-bound organelles.
Eukaryotic cells are often multicellular, have a nucleus, and contain membrane-bound organelles.
Identify the cellular organelles and their functions.
Key organelles include the nucleus (stores DNA), mitochondria (energy production), endoplasmic reticulum (protein and lipid synthesis), and Golgi apparatus (modifies and packages proteins).
What is a model organism? What model organisms are commonly used in biology research?
A model organism is a species extensively studied to understand biological processes.
Common examples: plasmodium, yeast, fruit flies, and mice.
What is meant by molecular complementarity?
Molecular complementarity refers to the specific interactions between molecules, such as the binding of substrates to enzymes or the pairing of nucleotides in DNA.
Allows for interactions.
Describe the characteristics of the following chemical bonds. What roles do each play in biological molecules?
Covalent, ionic, hydrogen, Van der Waals, hydrophobic interaction.
Covalent bonds (strong, share electrons)
ionic bonds (attraction between charged ions)
hydrogen bonds (weak, between polar molecules)
- stabilizies secondary structures
Van der Waals interactions (weak, due to transient dipoles)
- stabilizies teritary and quaternary structures
hydrophobic interactions (nonpolar molecules avoiding water).
- stabilizies teritary and quaternary structures
Explain the difference between hydrophilic, hydrophobic, and amphipathic molecules.
Hydrophilic molecules are water-attracting
Hydrophobic molecules are water-repelling
Amphipathic molecules have both hydrophilic and hydrophobic regions.
Identify the structure of a phospholipid and how phospholipids form cellular membranes.
A phospholipid consists of a hydrophilic head and two hydrophobic tails, forming a bilayer in cellular membranes.
The heads are on the outside and the tails are on the inside.
How can you determine whether a chemical reaction is spontaneous?
A chemical reaction is spontaneous if it has a negative Gibbs free energy change (ΔG < 0).
How do enzymes increase the rate of chemical reactions?
Enzymes increase reaction rates by lowering the activation energy required for the reaction.
Name and describe the four levels of protein structure.
Primary (amino acid sequence)
Secondary (alpha helices and beta sheets)
Tertiary (3D folding)
Quaternary (multiple polypeptide chains).
Describe the chemical structure of a polypeptide. What type of bond joins the amino acids? How are the two ends of a polypeptide identified? Which end is synthesized first?
A polypeptide is a chain of amino acids linked by peptide bonds. It has an N-terminus (amino end) and a C-terminus (carboxyl end), synthesis N-terminus to C-terminus.
Be able to interpret a free energy diagram, enzyme kinetics graph, Vmax, and Km describing an enzyme-catalyzed reaction.
A free energy diagram shows the energy changes during a reaction, while enzyme kinetics graphs plot reaction rate against substrate concentration, with Vmax being the maximum rate and Km being the substrate concentration at half Vmax.
How do chaperones promote proper folding of a protein?
Chaperones assist in the folding process by preventing misfolding and aggregation of polypeptides.
They provide an environment for folding to occur.
What is the function of the proteasome?
How does the proteasome recognize its protein targets?
The proteasome degrades unneeded or damaged proteins, recognizing targets by ubiquitin tags.
How is each of the following methods used to study proteins in the laboratory?
a. SDS-PAGE
b. Two-dimensional gel electrophoresis
SDS-PAGE separates proteins based on masses.
Two-dimensional gel electrophoresis separates proteins by both size and charge.
What is the central dogma of molecular biology?
Genetic information flows from DNA to RNA to protein.
What are the differences between DNA and RNA?
DNA is double-stranded, contains deoxyribose, and has thymine
RNA is single-stranded, contains ribose, and has uracil. Two OH groups.
What does it mean that DNA replication is:
a. Semiconservative?
b. Bidirectional?
c. Both continuous and discontinuous?
a. Semiconservative means each new DNA molecule has one old and one new strand.
b. Bidirectional means replication occurs in both directions from the origin.
c. Continuous refers to the leading strand, while discontinuous refers to the lagging strand.
Describe the chemical structure of a nucleic acid. What type of bond joins the nucleotides? How are the two ends of a polynucleotide molecule identified? Which end is synthesized first? How are the two strands of a DNA molecule held together?
Nucleic acids are composed of nucleotides linked by phosphodiester bonds.
The ends are identified as 5’ and 3’, with synthesis starting at the 5’ end.
The strands are held together by hydrogen bonds between complementary bases.
Compare and contrast the two methods of repairing a DNA double strand break.
Homologous recombination uses a homologous template for accurate repair.
Non-homologous end joining directly ligates the broken ends, which can lead to errors.
What are the three main types of RNA? What is the role of each?
Messenger RNA (mRNA, which carries genetic information)
Transfer RNA (tRNA, brings amino acids to ribosomes)
Ribosomal RNA (rRNA, forms the core of ribosome structure and function).
What three modifications occur during pre-mRNA processing? What is the purpose of each?
Capping (protects mRNA and aids in translation)
Polyadenylation (poly-a tail)
Splicing (removes introns and joins exons).
