Q: Which of the following best describes the role of the sodium-potassium pump ($$\text{Na}^+/\text{K}^+$$ pump) in maintaining the resting membrane potential of a neuron?

It actively transports $$3\ \text{Na}^+$$ out and $$2\ \text{K}^+ in$$, creating a negative charge inside the cell.

Question 1

Which structural feature distinguishes Gram-positive bacteria from Gram-negative bacteria, and how does this affect their response to antibiotics?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer and lack an outer membrane, making them more susceptible to antibiotics targeting cell wall synthesis.

Question 2

A bacterium is exposed to DNA fragments from a dead cell and incorporates them into its genome. Which process is this, and what is its significance?

Accepted Answer

Transformation; it increases genetic diversity by allowing uptake of foreign DNA.

Question 3

Which equation best represents the relationship between surface area ($$A) $$and volume ($$V) $$for a spherical cell, and why is this important for cell function?

Accepted Answer

Surface area: $$A = 4\pi r^2$, Volume: V$$ = \frac{4}{3}\pi $$r^3$$; as cell size increases, volume grows faster than surface area, limiting exchange rates.

Question 4

Which of the following best describes the role of the sodium-potassium pump ($$	ext{Na}^+/	ext{K}^+$$ pump) in maintaining the resting membrane potential of a neuron?

Accepted Answer

It actively transports $$3\ 	ext{Na}^+$$ out and $$2\ 	ext{K}^+ in$$, creating a negative charge inside the cell.

Question 5

During muscle contraction, which sequence of events occurs after an action potential reaches the neuromuscular junction?

Accepted Answer

Acetylcholine is released, depolarizing the muscle fiber; $$	ext{Ca}^{2+} is $$released from the sarcoplasmic reticulum, allowing actin-myosin interaction.

Question 6

Which of the following best explains the sliding filament model of muscle contraction?

Accepted Answer

Myosin heads bind to actin and pull the thin filaments toward the M line, shortening the sarcomere.

Question 7

Which process allows bacteria to survive extreme environmental conditions, such as high heat or desiccation, and what is its biological significance?

Accepted Answer

Endospore formation; it enables bacteria to remain dormant and resistant until conditions improve.

Question 8

Which of the following is a real-world example of negative feedback in homeostatic control, and which equation describes the feedback loop?

Accepted Answer

Regulation of blood glucose: insulin lowers glucose when levels are high; feedback loop: $$	ext{Output} = 	ext{Set Point} - 	ext{Current Value}.$$

Question 9

Which of the following best describes the process of endosymbiosis in the evolution of eukaryotic cells?

Accepted Answer

A eukaryotic cell engulfed a prokaryote, which became a mitochondrion or chloroplast, providing energy or photosynthesis.

Question 10

Which physical process is primarily responsible for heat loss in mammals through sweating, and which equation describes the rate of heat loss?

Accepted Answer

Evaporation; rate of heat loss: $$Q = mL$$, where $$m is $$mass of water evaporated and $$L is $$latent heat.

Question 11

Which of the following best explains the difference between slow-twitch and fast-twitch muscle fibers?

Accepted Answer

Slow-twitch fibers have high endurance and rely on aerobic metabolism; fast-twitch fibers contract quickly and fatigue rapidly, relying on anaerobic metabolism.

Question 12

Which mechanism allows for rapid propagation of action potentials along myelinated axons, and what is the underlying principle?

Accepted Answer

Saltatory conduction; action potentials jump between nodes of Ranvier, increasing speed.

Question 13

Which of the following best describes the function of mycorrhizae in plant-fungal mutualism?

Accepted Answer

Mycorrhizae increase nutrient and water uptake for plants, while fungi receive carbohydrates.

Question 14

Which equation describes the change in membrane potential ($$V_m) $$during depolarization, and what triggers this change?

Accepted Answer

$$V_m = V_{rest} + \Delta V$$; opening of voltage-gated $$	ext{Na}^+$$ channels triggers the change.

Question 15

Which of the following is a key difference between the central nervous system (CNS) and the peripheral nervous system (PNS)?

Accepted Answer

The CNS consists of the brain and spinal cord, while the PNS includes nerves and ganglia outside the CNS.

Question 16

Which of the following best describes the function of the thalamus and hypothalamus in the brain?

Accepted Answer

The thalamus relays sensory information; the hypothalamus regulates homeostasis and endocrine functions.

Question 17

Which of the following is a defining feature of Archaea compared to Bacteria, especially in extreme environments?

Accepted Answer

Archaea have unique membrane lipids and can survive extreme conditions such as high salinity and temperature.

Question 18

Which of the following best explains the role of ATP in muscle contraction and relaxation?

Accepted Answer

ATP provides energy for myosin head movement and is required to detach myosin from actin during relaxation.

BIOL 1720 Exam 1 Study Guide: Prokaryotes, Protists, Fungi, Animal Form & Function, Nervous System, and Muscles

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