General Biology Flashcards

Which of the following correctly describes the role of telomeres?

Answer: They protect chromosome ends from degradation and fusion

Telomeres are repetitive non-coding DNA sequences that cap chromosome ends, preventing degradation and end-to-end chromosome fusions during each cell division.

A species of insect evolves mimicry of a toxic species even though it is harmless. This is an example of:

Answer: Batesian mimicry

Batesian mimicry occurs when a harmless species evolves to resemble a harmful or toxic species, gaining protection from predators.

Which layer of the skin contains melanocytes that produce melanin?

Answer: Stratum basale

Melanocytes are located in the stratum basale (deepest epidermal layer) and produce melanin that is transferred to surrounding keratinocytes for UV protection.

What is the primary role of the corpus luteum after ovulation?

Answer: Secrete progesterone to maintain the uterine lining

The corpus luteum, formed from the ruptured follicle after ovulation, secretes progesterone (and some estrogen) to maintain the endometrium for potential implantation.

Which of the following describes an r-selected species?

Answer: Short lifespan, many offspring, little parental care

r-selected species maximize reproductive rate (high r) by producing many offspring with minimal parental investment, thriving in unpredictable environments.

Which process generates genetic diversity by exchanging segments between homologous chromosomes?

Answer: Crossing over

Crossing over (recombination) occurs during prophase I of meiosis when non-sister chromatids of homologous chromosomes exchange corresponding segments at chiasmata.

Which structure in the brain is most directly responsible for regulating homeostasis, hunger, and body temperature?

Answer: Hypothalamus

The hypothalamus is the master homeostatic regulator, controlling hunger, thirst, body temperature, circadian rhythms, and the release of pituitary hormones.