Question 1

Which of the following best describes the difference between kinesis and taxis in animal behavior?

Accepted Answer

Kinesis is a non-directional change in activity rate in response to a stimulus, while taxis is a directional movement toward or away from a stimulus.

Question 2

A patient is experiencing high blood glucose levels. Which feedback mechanism is primarily responsible for restoring homeostasis, and what is the general effect?

Accepted Answer

Negative feedback; insulin is released to lower blood glucose levels.

Question 3

Which of the following equations correctly represents logistic population growth, and what does each variable represent?

Accepted Answer

$$dN/dt = rN((K-N)/K)$$, where $$N is $$population size, $$r is $$intrinsic growth rate, and $$K is $$carrying capacity.

Question 4

A keystone species is removed from a community. What is the most likely ecological consequence?

Accepted Answer

A dramatic shift in community structure, potentially leading to loss of biodiversity.

Question 5

Which of the following best explains why ice floats on liquid water, and what is the ecological significance of this property?

Accepted Answer

Hydrogen bonds form a rigid lattice in ice, making it less dense than liquid water; this insulates aquatic life during winter.

Question 6

Which functional group is responsible for the acidic properties of amino acids and fatty acids, and what is its structure?

Accepted Answer

Carboxyl group $$(−COOH)$$; a carbon double-bonded to oxygen and single-bonded to a hydroxyl group.

Question 7

A scientist is studying a molecule with the formula $$C_6H_{12}O_6$. She finds that it has a different structure from glucose but the same formula. What type of isomer is this molecule?

Accepted Answer

Structural isomer

Question 8

Which of the following best describes the amphipathic nature of phospholipids and its importance in biological membranes?

Accepted Answer

Phospholipids have hydrophilic heads and hydrophobic tails, allowing them to form bilayers that create selectively permeable membranes.

Question 9

A red blood cell is placed in a solution and begins to swell and eventually bursts. What is the tonicity of the solution relative to the cell, and what is the process responsible for this outcome?

Accepted Answer

The solution is hypotonic; water enters the cell by osmosis.

Question 10

Which of the following best explains why only about 10% of energy is transferred from one trophic level to the next in an ecosystem?

Accepted Answer

Most energy is lost as metabolic heat or remains in unconsumed biomass.

Question 11

Which of the following equations is used to calculate the solute potential $$(\Psi_s) of a $$solution, and what does each variable represent?

Accepted Answer

$$\Psi_s = -iCRT$$, where $$i is $$the ionization constant, $$C is $$molar concentration, $$R is $$the pressure constant, and $$T is $$temperature in Kelvin.

Question 12

A plant cell is placed in a solution with a solute potential $$(\Psi_s) of$$ $$-0.5$$ bars and a pressure potential $$(\Psi_p) of$$ $$0.3$$ bars. What is the total water potential $$(\Psi) of $$the cell, and in which direction will water move if the surrounding solution has a water potential of $$-0.1$$ bars?

Accepted Answer

$$\Psi = -0.2$$ bars; water will move out of the cell.

Question 13

Which of the following best describes the role of cholesterol in animal cell membranes?

Accepted Answer

Cholesterol stabilizes membrane fluidity by preventing excessive rigidity at low temperatures and excessive fluidity at high temperatures.

Question 14

During the Stanley Miller experiment, which of the following was demonstrated regarding the origin of life?

Accepted Answer

Organic monomers such as amino acids can form abiotically from inorganic gases under simulated prebiotic conditions.

Question 15

Which of the following is NOT a true polymer, and why?

Accepted Answer

Lipids; they are composed of distinct components (glycerol and fatty acids) rather than repeating identical monomers.

Question 16

A cell is actively transporting sodium ions $$(Na^+)$$ out and potassium ions $$(K^+) in$$, both against their concentration gradients. Which transport protein is responsible, and what is the energy source?

Accepted Answer

Sodium-potassium pump (Na+/K+ ATPase); energy is provided by ATP hydrolysis.

Question 17

Which of the following best explains why water is an excellent solvent for many biological molecules?

Accepted Answer

Water is polar and forms hydration shells around charged and polar molecules, allowing them to dissolve.

Question 18

Which of the following best describes the process of receptor-mediated endocytosis?

Accepted Answer

Specific extracellular ligands bind to cell-surface receptors, triggering vesicle formation and uptake of the ligand-receptor complex.

General Biology Study Guide: Ecology, Chemistry of Life, and Cell Membranes

Guida di studio - Domande di pratica

Study guide - Flashcard