Bio 161: Anatomy and Physiology Exam 1

Correct Answer:

The movement of one substance down its concentration gradient

Explanation:

Secondary active transport does not directly use ATP. Instead, it relies on the energy stored in the concentration gradient of one substance, often created by primary active transport. As this substance moves down its gradient, the released energy is harnessed to move another substance against its gradient. This process is crucial in nutrient uptake and ion balance, such as sodium-glucose cotransport in the intestines.

Why Other Options Are Wrong:

The direct use of ATP. This is incorrect because direct ATP usage is a feature of primary active transport, not secondary active transport.

The diffusion of gases. This is wrong because gas diffusion is a passive process, independent of secondary active transport mechanisms.

The osmosis of water. This is inaccurate because osmosis is passive water movement, not a driver of secondary active transport.

Correct Answer:

double covalent bond

Explanation:

A double covalent bond occurs when two atoms share two pairs of electrons, resulting in a stronger and shorter bond than a single bond. Common in molecules like O₂ or CO₂, double bonds play a key role in molecular structure and reactivity. They also affect the molecule’s shape and chemical properties due to restricted rotation.

Why Other Options Are Wrong:

single covalent bond

This involves only one pair of shared electrons. Two pairs of shared electrons indicate a double bond, not a single one.

triple covalent bond

This occurs when three pairs of electrons are shared. It is stronger than a double bond, but not the correct type in this context.

polar covalent bond

This describes the unequal sharing of electrons, not the number of electron pairs. A polar covalent bond can be single, double, or triple depending on the context.

hydrogen bond

A hydrogen bond is a weak attraction between a hydrogen atom and an electronegative atom like oxygen or nitrogen. It does not involve the sharing of electron pairs between two atoms.

Correct Answer:

It lowers the pH, potentially disrupting normal cellular functions

Explanation:

Acidosis is a condition in which the body’s pH drops below the normal range (7.35–7.45), becoming more acidic. This decrease in pH can impair enzyme function, alter cellular ion balance, and disrupt vital physiological processes. The body attempts to compensate through respiratory or renal adjustments, but prolonged acidosis can lead to serious health issues if not corrected.

Why Other Options Are Wrong:

It raises the pH, leading to alkalosis

This is the opposite of what occurs in acidosis. A raised pH results in alkalosis, not acidosis. Acidosis specifically refers to a decrease in pH.

It has no effect on pH

This is incorrect because acidosis, by definition, involves a reduction in pH. Its entire clinical relevance centers around pH imbalance.

It stabilizes pH levels

Acidosis does not stabilize pH; rather, it represents a deviation from the normal range. It destabilizes internal conditions and requires physiological correction to restore balance.

Correct Answer:

Positive, lose

Explanation:

A cation is an ion with a net positive charge. This happens when an atom loses one or more electrons, since electrons are negatively charged. Losing these negative charges leaves the atom with more protons than electrons, creating an overall positive charge. Cations are common in metals, such as sodium (Na⁺), which loses an electron to form a positively charged ion.

Why Other Options Are Wrong:

Positive, gain

Gaining electrons adds negative charge, not positive, so this would create an anion instead of a cation.

Negative, lose

Losing electrons reduces negative charges, which makes the atom more positive, not negative. This describes the opposite of what happens in cation formation.

Negative, gain

When an atom gains electrons, it becomes negatively charged (an anion), not a positively charged cation. This is inaccurate.

Correct Answer:

The cell will adjust its internal mechanisms to stabilize its functions despite the temperature change

Explanation:

Autoregulation refers to the ability of a cell, tissue, or organ to automatically adjust its internal processes to maintain stability in response to environmental changes. When a cell experiences a sudden increase in temperature, autoregulation helps maintain homeostasis by altering enzyme activity, protein folding, or membrane fluidity to ensure survival. This allows the cell to continue functioning without shutting down or self-destructing, preserving stability until conditions normalize.

Why Other Options Are Wrong:

The cell will stop all functions to prevent damage. This is incorrect because cells rarely shut down completely; doing so would be fatal. Instead, autoregulation ensures continued function, even if at modified efficiency. Stopping all functions is not a protective mechanism but rather cell death.

The cell will enhance its metabolic rate to cope with the heat. This is wrong because increasing metabolic rate would generate more heat, worsening the stress. Autoregulation seeks balance, not escalation, and typically involves stabilizing internal processes, not overdriving them.

The cell will undergo apoptosis to prevent further damage. This is inaccurate because apoptosis is programmed cell death, which occurs in severe, irreparable conditions. Autoregulation is a survival mechanism aimed at maintaining function, not a pathway for self-destruction.

Correct Answer:

DNA

Explanation:

DNA (deoxyribonucleic acid) is the molecule responsible for storing the genetic instructions used in the development, function, and reproduction of all living organisms. It contains the coded sequences for protein synthesis and is passed from generation to generation. Its double-helix structure allows for replication and long-term information storage.

Why Other Options Are Wrong:

RNA

RNA plays a key role in translating genetic information into proteins, but it does not store genetic information long term. It acts as a messenger and functional molecule.

protein

Proteins are the products of genetic instructions and perform various cellular functions, but they do not contain or store genetic information.

enzymes

Enzymes are specialized proteins that catalyze reactions. They depend on genetic information to be made but do not store that information themselves.

glucose

Glucose is a carbohydrate that stores energy, not genetic information. It plays no role in inheritance or genetic coding.

Correct Answer:

The complete living entity that can carry out all basic life processes

Explanation:

The organismal level of organization represents the highest level in human anatomy. It refers to the entire body functioning as a single living entity capable of carrying out all life processes such as growth, reproduction, responsiveness, metabolism, and homeostasis. This level integrates all other levels of organization, from cellular to system, into a unified whole.

Why Other Options Are Wrong:

The collection of similar cells working together to perform a specific function

This describes the tissue level of organization, not the organismal level. Tissues are just one step in the hierarchy.

The group of organs that work together to perform complex functions

This describes the organ system level, such as the digestive or respiratory system, not the complete organism.

The arrangement of tissues that form a specific structure

This is the organ level of organization, where different tissues combine to form a single functional unit like the heart or liver.

Correct Answer:

D. Formation of new cells or new organisms

Explanation

Reproduction is the biological process through which living organisms produce new cells for growth, repair, and maintenance, or new organisms for the continuation of the species. At the cellular level, this occurs through mitosis (producing identical cells) and meiosis (producing gametes for sexual reproduction). Reproduction ensures the survival of life by allowing organisms to pass on genetic material to future generations.

Why Other Options Are Wrong

A. Formation of old cells or old organisms

This is incorrect because reproduction does not involve creating old cells or organisms; it produces new ones.

B. Formation of old cells or new organisms

This option is partially incorrect since reproduction always results in new cells at the cellular level, not old cells.

C. Formation of new cells or old organisms

Although new cells are formed, reproduction does not produce old organisms; it creates new organisms to sustain life.

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.