Biology Flashcards
7 cards from real PCAT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Biology flashcards as text
Which organelle is primarily responsible for producing ATP through oxidative phosphorylation?
Answer: Mitochondria
Mitochondria generate ATP via oxidative phosphorylation in their inner membrane through the electron transport chain and ATP synthase.
During meiosis II, which event separates sister chromatids?
Answer: Anaphase II
During Anaphase II, cohesins break down and sister chromatids are pulled to opposite poles of the cell.
What type of RNA carries amino acids to the ribosome during translation?
Answer: tRNA
Transfer RNA (tRNA) carries specific amino acids and matches them to codons on mRNA via its anticodon loop.
The sodium-potassium pump moves ions against their concentration gradient using which energy source?
Answer: ATP hydrolysis
The Na⁺/K⁺-ATPase uses ATP hydrolysis to pump 3 Na⁺ out and 2 K⁺ into the cell against their gradients.
Which type of mutation results in a premature stop codon?
Answer: Nonsense mutation
A nonsense mutation changes an amino acid codon into a stop codon (UAA, UAG, or UGA), prematurely terminating translation.
In which phase of the cell cycle does DNA replication occur?
Answer: S phase
DNA synthesis (replication) occurs during the S (synthesis) phase of interphase, duplicating the genome before cell division.
Which immunoglobulin class is the most abundant in serum and provides long-term immunity?
Answer: IgG
IgG is the most abundant serum antibody (~75%), crosses the placenta, and provides long-lasting humoral immunity after infection or vaccination.