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Biology Flashcards

7 cards from real OAT 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

  1. Which layer of the skin contains melanocytes?

    Answer: Stratum basale

    Melanocytes reside in the stratum basale (deepest epidermal layer) and produce melanin pigment.

  2. The Calvin cycle (light-independent reactions) occurs in which part of the chloroplast?

    Answer: Stroma

    Carbon fixation via the Calvin cycle takes place in the stroma, where RuBisCO converts CO₂ into G3P.

  3. Which immunoglobulin class is the FIRST to be produced in a primary immune response?

    Answer: IgM

    IgM is the first antibody produced during a primary immune response before class switching occurs.

  4. The enzyme that unwinds the double helix ahead of the replication fork is called:

    Answer: Helicase

    Helicase breaks hydrogen bonds between base pairs to unwind the DNA double helix at the replication fork.

  5. Which of the following is an example of negative feedback in the endocrine system?

    Answer: Progesterone inhibiting FSH and LH secretion

    Progesterone's inhibition of FSH and LH is classic negative feedback, dampening the hormone signal that caused its release.

  6. In a dihybrid cross between two AaBb individuals, what fraction of offspring are expected to be aabb?

    Answer: 1/16

    Each locus independently has a 1/4 chance of yielding the homozygous recessive; combined probability = 1/4 × 1/4 = 1/16.

  7. Which type of muscle tissue is involuntary and striated?

    Answer: Cardiac muscle

    Cardiac muscle is involuntary (autonomically controlled) and striated due to organized sarcomere structure.