The movement of substances from lower to higher concentration across a semipermeable membrane that must have a specific protein carrier and cell expenditure of energy is called
facilitated diffusion
endocytosis.
active transport
osmosis
diffusion
The Correct Answer is C
A. facilitated diffusion: Facilitated diffusion is the movement of substances across a cell membrane via specific carrier proteins or channels, but it occurs along the concentration gradient (from high to low) and does not require cellular energy. It relies on the natural kinetic energy of molecules rather than ATP.
B. endocytosis: Endocytosis involves the engulfing of large particles or liquids by the cell membrane to bring them into the cell. Although it requires energy, it is a bulk transport mechanism rather than the specific movement of molecules against a concentration gradient using a carrier protein.
C. active transport: Active transport is the movement of molecules against their concentration gradient (from lower to higher concentration) using specific transport proteins and energy expenditure, typically in the form of ATP. Examples include the sodium-potassium pump and calcium pumps in cell membranes, which maintain essential ionic gradients for cell function.
D. osmosis: Osmosis is the passive movement of water molecules across a semipermeable membrane from an area of low solute concentration to high solute concentration. It does not require energy or a carrier protein and is specific to water movement.
E. diffusion: Diffusion is the passive movement of molecules from an area of higher concentration to lower concentration down their concentration gradient. It does not require energy or proteins and is driven by molecular motion, unlike active transport which moves substances against the gradient.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
In gram-negative bacteria, the cell envelope is a complex structure composed of three main layers: an inner (cytoplasmic) membrane, a periplasmic space, and an outer membrane. The inner membrane is a phospholipid bilayer that regulates transport and energy production. The periplasmic space lies between the inner and outer membranes and contains a thin layer of peptidoglycan along with enzymes involved in nutrient processing and defense. The outer membrane contains lipopolysaccharides (LPS), porins, and other proteins that provide structural support, act as a barrier to certain antibiotics, and contribute to the organism’s pathogenicity.
100 Multiple Choice 0.5 points
Correct Answer is D
Explanation
A. an extremophile: Extremophiles are organisms that thrive in extreme environmental conditions, such as very high or very low pH, salinity, or pressure. While thermophiles can be considered a type of extremophile, the term extremophile is broader and does not specifically describe organisms adapted primarily to high temperatures.
B. thermoduric: Thermoduric organisms are those that can survive short exposures to high temperatures but do not necessarily grow optimally at those temperatures. They are often heat-resistant spores or bacteria that survive pasteurization, rather than thriving at 45–60°C.
C. a facultative psychrophile: Facultative psychrophiles are organisms capable of growing at low temperatures but can tolerate higher temperatures. Their optimal growth range is typically below 20°C, making this classification inconsistent with a 45–60°C growth range.
D. a thermophile: Thermophiles are microorganisms that grow optimally at elevated temperatures, typically between 45°C and 80°C. They possess enzymes and cellular structures adapted to resist denaturation at high temperatures, which allows them to thrive in environments such as hot springs, compost piles, or industrial processes.
E. a psychrophile: Psychrophiles are cold-loving organisms that grow optimally at temperatures below 15°C and are adapted to Arctic, Antarctic, or deep-sea habitats. A growth range of 45–60°C is far beyond their tolerance, making this classification incorrect.
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