Spring 2026 Biology Exam 01 Practice Flashcards

To which category of nucleic acids does ATP belong based on its chemical structure?

ATP belongs to the category of RNA because it contains a ribose sugar with hydroxyl ($\text{OH}$) groups on both the $2'$ and $3'$ carbon positions.

What is the primary structure of a protein, and what type of bond joins its monomers?

The primary structure is the specific linear sequence of amino acids linked together by peptide bonds.

What bond type forms secondary protein structures, and what are two common secondary structure shapes?

Hydrogen bonds form secondary protein structures, which commonly fold into an $\alpha$-helix or a $\beta$-pleated sheet.

What four chemical groups are bound to the central carbon atom in an amino acid?

An amino acid central carbon is bonded to an amino group, a carboxyl group, a hydrogen atom, and a side group (R group).

What are the key functional roles of proteins highlighted in cell biology?

Proteins serve as enzyme catalysts, transport molecules across membranes via facilitated diffusion, function as signaling hormones like insulin, protect the body as antibodies in the immune system, and provide structural support such as collagen or actin and myosin in muscles.

What are the three components of a nucleotide, and what bond links them into nucleic acid polymers?

A nucleotide consists of a phosphate group, a 5-carbon sugar (ribose or deoxyribose), and a nitrogenous base. Nucleotides are linked together by phosphodiester bonds.

Which nitrogenous bases belong to purines, and which belong to pyrimidines?

Adenine and guanine are purines, whereas cytosine and thymine (and uracil in RNA) are pyrimidines.

How do light microscopy, fluorescent microscopy, and electron microscopy differ in their underlying mechanisms and observational capabilities?

Light microscopy uses visible light to observe general cell structures and larger organelles; fluorescent microscopy uses specific wavelengths to excite fluorophores for tracking targeted molecules; electron microscopy uses electron beams to achieve sub-nanometer resolution for visualizing cellular ultrastructure and macromolecular complexes.

How do prokaryotic and eukaryotic cells differ in structural organization?

Prokaryotic cells lack a membrane-enclosed nucleus and internal organelles, whereas eukaryotic cells possess a distinct nucleus and membrane-bound organelles that compartmentalize specific metabolic functions.

Why do scientific researchers use model organisms?

Scientists use model organisms because they are easy to grow and maintain in laboratory settings, reproduce quickly, have well-characterized genetics, and share conserved fundamental biological processes with other species, including humans.

How do cells utilize high-energy phosphate bonds to perform work?

Cells utilize high-energy phosphate bonds (such as those in ATP) by hydrolyzing them to release free energy, which is directly coupled to drive energetically unfavorable chemical reactions and mechanical cellular tasks.

Disulfide bonds are covalent linkages formed between the thiol groups of two cysteine amino acids; they stabilize tertiary and quaternary protein structures, particularly in extracellular environments.