W1 summary + mc questions Flashcards
sugars
Key Families of Organic Molecules:
Monomers and Polymers: Monomers (e.g., sugars, amino acids) link to form polymers (e.g., polysaccharides, proteins).
Sugars: Energy sources and subunits of polysaccharides.
Monosaccharides (e.g., glucose) follow the formula (CH2O)n.
Covalent glycosidic bonds form polysaccharides like glycogen and starch.
Condensation Reactions: Bond formation by removing water; Hydrolysis: Breaking bonds by adding water.
fatty acids
Components of membranes and energy storage.
Structure: Hydrophobic hydrocarbon tail + hydrophilic carboxyl group.
Saturated (no double bonds) vs. Unsaturated (one or more double bonds).
Stored as triacylglycerols (three fatty acids linked to glycerol).
protein composition
Amino Acids: Building blocks of proteins, linked by peptide bonds.
Polypeptides: Chains of amino acids with specific 3D structures stabilized by noncovalent bonds.
Enzyme function depends on substrate binding through specific noncovalent interactions.
nucleotides and nucleic acids
DNA and RNA Subunits:
-Nucleotides: Nitrogenous base + 5-carbon sugar (ribose or deoxyribose) + phosphate group.
Bases: Purines (adenine, guanine) and Pyrimidines (cytosine, thymine, uracil).
DNA: Long-term genetic information storage.
RNA: Short-term information carrier.
Linked by phosphodiester bonds between sugar and phosphate groups.
Properties of Water:
Polar molecule with hydrogen bonding capabilities.
High boiling point, surface tension, and ability to dissolve hydrophilic substances.
Hydrophobic molecules cluster to minimize interaction with water (e.g., lipid bilayers).
Explain why fatty acids are considered amphipathic.
How do glycosidic bonds differ from peptide bonds?
- Which of the following reactions is energetically favorable?
A. Condensation reaction
B. Hydrolysis reaction
C. Photosynthesis
D. Protein synthesis
Answer: B
why are G-C base pairs more stable than A-T base pairs?
A. They form covalent bonds
B. They involve van der Waals interactions
C. They form three hydrogen bonds instead of two
D. They are hydrophobic
Answer: C
Which term describes molecules that have both hydrophobic and hydrophilic regions?
A. Amphipathic
B. Isomeric
C. Hydrophilic
D. Hydrophobic
Answer: A
What kind of bond links amino acids in a protein?
A. Glycosidic bond
B. Hydrogen bond
C. Ionic bond
D. Peptide bond
Answer: D
What is the role of buffers in biological systems?
A. Catalyzing chemical reactions
B. Stabilizing proton concentrations at around pH 7
C. Serving as energy storage molecules
D. Facilitating hydrolysis reactions
Answer: B
What is the general formula for monosaccharides?
A. (CH3O)n
B. (CH2O)n
C. (C2HO)n
D. (C3H6O)n
Answer: B
Why are phospholipids ideal for forming cell membranes?
A. They are hydrophilic
B. They are amphipathic, with hydrophilic heads and hydrophobic tails
C. They are hydrophobic
D. They contain only saturated fatty acids
Answer: B
How do condensation and hydrolysis reactions differ?
A. Hydrolysis builds polymers; condensation breaks them down
B. Hydrolysis adds water to break bonds; condensation removes water to form bonds
C. Both require energy input
D. Both involve amino acids exclusively
Answer: B
Which statement about fatty acids is true?
A. Saturated fatty acids have one or more double bonds
B. Unsaturated fatty acids are completely hydrogenated
C. Fatty acids are stored as triacylglycerols
D. Fatty acids only function as membrane components
Answer: C
What property allows water to dissolve hydrophilic substances?
A. Its nonpolar nature
B. Hydrogen bonding and polarity
C. Its ability to form ionic bonds
D. Its amphipathic nature
Answer: B