Unit 3: Challenges of Life - Flashcards

These flashcards cover key concepts from the lecture notes on the universal challenges of life, cell membranes, genetic material, energy metabolism, homeostasis, signaling, and more.

The __________ helps organisms respond to stressors that threaten survival, involving coordination of responses, defense against threats, nutrient acquisition, energy utilization, transport, reproduction, and growth.

hypothalamic–pituitary–adrenal (HPA) axis

The cell membrane acts as a __________ barrier, regulating the movement of water and solutes to maintain a stable internal environment.

selective

Genetic material contributes to trait variation through processes such as __________ during meiosis, which creates new combinations of alleles.

recombination

Halobacterium salinarum is classified as a __________ as it gains energy from light and fixes carbon from organic compounds.

photoautotroph

A spherical shaped bacterium that doubles its diameter may struggle to maintain homeostasis because its __________ decreases relative to its volume, slowing diffusion.

surface area-to-volume ratio

The __________ in blood vessels detected increasing body temperature, causing vasodilation and activation of heat loss mechanisms.

chemoreceptors

Plants release __________ signals in response to herbivore attacks, which alert neighboring plants and attract parasitic wasps for defense.

chemical

Certain plants have tough, fibrous leaves that serve as a __________ mechanism, physically deterring herbivores from feeding.

mechanical defense

A population of fish may experience seasonal shifts in salinity by altering their __________ cell structure and kidney function to survive.

gill

The ability to rapidly produce genetically diverse and resistant offspring through sexual reproduction arises under __________ conditions in organisms like Volvox.

stressful

The __________ stage of development in animals involves the transformation into a hollow ball of cells, a process not present in plants.

blastula

A fundamental difference in development between plants and animals is that animal cells undergo __________, allowing them to move and use hormones for communication.

migration

The process during which a bacterium incorporates a DNA fragment from the environment into its genome is known as __________.

transformation

Plants may utilize __________ in response to being grazed upon, which helps to combat herbivore pressure.

chemical defenses

The __________ mechanism allows organisms to reduce gill surface area during high salinity, minimizing water gain by osmosis.

physiological adaptation

Cell membranes are primarily composed of a __________ bilayer, which is critical for maintaining homeostasis within cells.

phospholipid

Mitosis produces __________ cells, while meiosis produces genetically diverse haploid gametes.

identical

During chemical signaling in organisms, messages are transmitted via __________, which can lead to physiological responses across diverse species.

hormones

A __________ response is initiated when a student inhales pollen, resulting in an immediate sneeze compared to the delayed immune response to a virus.

reflex

The __________ exchange where capillaries slow blood flow helps optimize diffusion of gases and nutrients at tissues, essential for larger organisms.

countercurrent