Bio 161: Anatomy and Physiology Exam 1

Correct Answer:

Study of body's structure and location of body parts.

Explanation:

Anatomy is the branch of biology concerned with the study of the structure of organisms and their parts. It specifically examines the form, location, and relationships of body parts, such as muscles, bones, and organs. This is different from physiology, which studies function, and pathology, which studies disease-related changes. Understanding anatomy provides the foundation for identifying how the body is organized and how systems interconnect.

Why Other Options Are Wrong:

Study of processes and functions of the body parts. This is incorrect because that definition describes physiology, not anatomy.

Study of structural and functional changes in tissues and organs that lead to disease. This is wrong because this describes pathology, not anatomy.

All of the above. This is inaccurate because anatomy specifically focuses on structure, not function or disease.

Correct Answer:

Triple covalent bond

Explanation:

A triple covalent bond occurs when two atoms share three pairs of electrons, meaning six electrons in total. In the case of two carbon atoms, this results in a strong and short bond, as seen in molecules like acetylene (C₂H₂). The sharing of multiple electron pairs allows atoms to achieve stable electron configurations. Triple bonds are stronger and shorter than double or single covalent bonds.

Why Other Options Are Wrong:

Single covalent bond. This is incorrect because a single bond only involves one pair of shared electrons, not three.

Ionic bond. This is wrong because ionic bonds involve electron transfer between atoms, not sharing of electrons as in covalent bonds.

Double covalent bond. This is inaccurate because a double bond consists of two pairs of shared electrons, fewer than a triple bond.

Polar covalent bond. This is incorrect because polarity refers to unequal sharing of electrons, not the number of electron pairs shared. A triple bond may be polar or nonpolar depending on the atoms involved.

Correct Answer:

Enzyme specificity ensures that enzymes only interact with certain substrates, preventing unwanted reactions.

Explanation:

Enzyme specificity means that each enzyme is designed to bind to a particular substrate or a group of closely related substrates. This specificity is due to the precise fit between the enzyme’s active site and the substrate, often described as a “lock-and-key” model. It ensures that enzymes catalyze only the intended reactions, avoiding harmful or wasteful side reactions. Specificity is crucial for maintaining regulation, efficiency, and order in biological systems.

Why Other Options Are Wrong:

Enzyme specificity allows enzymes to work on any substrate, increasing reaction rates. This is incorrect because enzymes cannot work on all substrates. They are highly selective and act only on specific ones.

Enzyme specificity is irrelevant to biological processes. This is wrong because specificity is essential to keep metabolic pathways organized and efficient. Without it, cellular reactions would be chaotic.

Enzyme specificity refers to the speed at which enzymes catalyze reactions. This is inaccurate because specificity is about substrate selection, not reaction speed. Reaction speed relates to enzyme efficiency, not specificity.

Correct Answer:

C. Anterior

Explanation

The term anterior refers to a position towards the front of the body. In humans, structures located on the belly side, such as the chest, abdomen, and face, are considered anterior. This term is commonly used in anatomical descriptions to indicate orientation relative to other body parts.

Why Other Options Are Wrong

A. Dorsal

The term dorsal refers to the back side of the body, also known as posterior in human anatomy. It is the opposite of anterior, making this option incorrect.

B. Medial

Medial means toward the midline of the body, not specifically toward the front. For example, the nose is medial to the eyes, but that does not describe anterior positioning.

D. Lateral

Lateral refers to a position away from the midline of the body, toward the sides. For example, the arms are lateral to the chest. It does not describe being toward the front.

Correct Answer:

crural

Explanation:

The crural region refers to the front of the lower leg, commonly known as the shin area. This anatomical term specifically identifies the part of the leg extending from the knee to the ankle on the anterior side. Because the shin is located in this region, "crural" is the correct answer.

Why Other Options Are Wrong:

carpal

The carpal region refers to the wrist, which is part of the upper limb. It has no association with the lower leg or shin. Selecting this would misplace the shin area entirely.

femoral

The femoral region identifies the thigh, located above the knee. While it is part of the leg, it is not the shin area, which lies below the knee. Therefore, this is not the correct anatomical match.

pubic

The pubic region refers to the genital area at the front of the pelvis. It is located much higher than the shin and has no relation to the lower leg. Thus, this option is incorrect.

Correct Answer:

Because solute concentrations are equal inside and outside the cell

Explanation:

In an isotonic solution, the concentration of solutes is the same inside and outside the cell, resulting in no net movement of water. While water still moves across the membrane in both directions, the movement is balanced, so the cell neither swells nor shrinks. This equilibrium maintains the cell’s normal shape and volume.

Why Other Options Are Wrong:

Because water moves out of the cell

If water moved predominantly out of the cell, the cell would shrink. That would occur in a hypertonic solution, not an isotonic one.

Because the cell actively transports solutes

While cells do transport solutes, active transport is not the reason a cell maintains size in an isotonic solution. The balance is due to equal solute concentration, not active processes.

Because the cell membrane is impermeable to water

This is false. Water moves freely across most cell membranes through aquaporins and diffusion. The ability to balance water movement is what maintains size in an isotonic environment.

Correct Answer:

B. Elimination of carbon dioxide

Explanation

The urinary system plays a vital role in filtering blood, removing metabolic wastes, maintaining fluid and electrolyte balance, regulating blood pressure, and contributing to acid-base balance. However, the elimination of carbon dioxide (CO₂) is primarily performed by the respiratory system through exhalation. The kidneys do help regulate blood pH, but CO₂ removal is not their function.

Why Other Options Are Wrong

A. Regulation of blood pressure

The urinary system regulates blood pressure by controlling blood volume through urine production and by releasing renin, an enzyme that activates the renin-angiotensin-aldosterone system (RAAS), which helps maintain blood pressure.

C. Maintenance of acid-base balance

The kidneys help maintain the body's pH by excreting hydrogen ions and reabsorbing bicarbonate from urine. This process plays an essential role in preventing acidosis or alkalosis, making this function directly linked to the urinary system.

D. Regulation of water and electrolytes

The urinary system maintains fluid balance by controlling water excretion and regulating electrolytes like sodium, potassium, and calcium. This ensures proper hydration and supports normal cell and organ function, making this a critical role of the kidneys.

Correct Answer:

Receptor, Control Center, Effector

Explanation:

Feedback mechanisms rely on three essential components to maintain homeostasis. Receptors detect changes in the environment, such as temperature or blood pressure, and send this information to the control center. The control center, often the brain or endocrine glands, processes the data and decides on an appropriate response. Effectors then carry out the response, such as muscles contracting or glands releasing hormones, helping to restore balance in the system.

Why Other Options Are Wrong:

Stimulus, Response, Feedback. This is incorrect because while these terms describe a sequence of events, they are not the actual components of a feedback mechanism. The mechanism relies on specific roles played by receptors, control centers, and effectors.

Input, Process, Output. This is wrong because these terms are general systems concepts, not specific to biological feedback. Biological regulation depends on the detection of stimuli, decision-making, and response by defined structures.

Sensor, Regulator, Actuator. This is inaccurate because although these terms resemble the functions, they are not the standard terminology used in biology. The proper biological components are receptors, control centers, and effectors.

Correct Answer:

It is essential for optimal enzyme activity

Explanation:

The human body must maintain a stable temperature of about 37°C (98.6°F) because enzymes, which drive virtually all biochemical reactions, function best at this temperature. Even small deviations can reduce enzyme efficiency, disrupt metabolic pathways, and impair normal cellular activity. This stable temperature is therefore critical for sustaining life processes and overall homeostasis.

Why Other Options Are Wrong:

It enhances the absorption of nutrients

While body temperature can affect digestion indirectly, nutrient absorption depends more on intestinal surface area and transport mechanisms, not temperature.

It regulates blood pressure

Blood pressure is primarily controlled by cardiac output, blood volume, and vascular resistance. Temperature has only a minor influence and is not the main regulator.

It promotes faster muscle recovery

Muscle recovery is linked to oxygen supply, nutrient delivery, and waste removal. While warmth can improve circulation, this is not the primary reason body temperature must remain near 37°C.