Ch1
Which of the following best describes a positive feedback mechanism?
A) It reverses a deviation from the normal set point to maintain stability.
B)It always returns the body to homeostasis.
C) It amplifies a change in the same direction until a specific event is completed.
D) It operates independently of receptors and effectors.
C, Positive feedback enhances or accelerates a process, leading to greater change in the same direction—like contractions during childbirth or clot formation.
If an atom has 8 protons, 9 neutrons, and 8 electrons, what is its atomic mass and charge?
A) Mass = 16, neutral
B) Mass = 17, neutral
C) Mass = 16, +1 charge
D) Mass = 17, –1 charge
B, Atomic mass = protons + neutrons = 8 + 9 = 17. Since electrons = protons, the atom is neutral.
Which organelle is directly responsible for modifying, packaging, and directing proteins to their final destinations within or outside the cell?
A) Rough endoplasmic reticulum
B) Smooth endoplasmic reticulum
C) Golgi apparatus
D) Nucleus
C, The Golgi apparatus receives proteins from the rough ER through vesicles, modifies them, and packages them into secretory vesicles for transport.
A patient has lung damage that reduces the efficiency of gas exchange. Which epithelial tissue is most likely affected, and what physiological function is impaired?
A) Stratified squamous epithelium – protection from abrasion
B) Simple cuboidal epithelium – secretion and absorption
C) Pseudostratified columnar epithelium – mucus secretion and propulsion
D) Simple squamous epithelium – diffusion and filtration
D, Simple squamous epithelium in the alveoli allows rapid gas diffusion; damage limits oxygen and carbon dioxide exchange.
Which statement correctly distinguishes thick skin from thin skin?
A) Thick skin has sebaceous glands and hair follicles, while thin skin does not.
B) Thick skin covers most of the body and lacks the stratum lucidum.
C) Thick skin has five epidermal layers, including the stratum lucidum, and lacks hair follicles and sebaceous glands.
D) Thin skin has five epidermal layers and no sweat glands.
C, Thick skin (palms, soles, fingertips) has five layers—including the stratum lucidum—and contains sweat glands but no hair follicles or sebaceous glands.
The serous membrane directly covering the heart is called the:
A) Pericardium
B) Pleura
C) Peritoneum
D) Meninges
A, The pericardium is the serous membrane around the heart. Pleura surrounds lungs, peritoneum covers abdominal organs, and meninges surround brain/spinal cord.
Which of the following best describes a polar covalent bond?
A) Electrons are shared equally between two atoms.
B) One atom donates electrons completely to another, forming ions.
C) Electrons are shared unequally, creating regions of slight positive and negative charge.
D) It forms between hydrogen and carbon atoms only.
C, In a polar covalent bond, electrons are shared unequally, producing partial charges on opposite sides of the molecule (e.g., water).
Which of the following correctly describes the difference between transmembrane and peripheral proteins?
A) Transmembrane proteins adhere to one face of the membrane, while peripheral proteins pass through it.
B) Transmembrane proteins pass through the membrane, while peripheral proteins attach to only one side of it.
C) Peripheral proteins drift freely within the lipid bilayer, while transmembrane proteins are anchored to the cytoskeleton.
D) Both are equally distributed and identical in structure.
B, Transmembrane (integral) proteins span the entire membrane and interact with both sides, while peripheral proteins attach to one face, usually tethered to the cytoskeleton.
When lifting a heavy object, tendons resist pulling forces mainly due to which physiological property of their connective tissue?
A) Parallel arrangement of collagen fibers providing tensile strength
B) High vascularity providing rapid nutrient exchange
C) Random orientation of collagen allowing stretch in all directions
D) Abundant ground substance with elastic fibers
A, Dense regular connective tissue has parallel collagen fibers that provide high tensile strength in one direction.
Which of the following correctly matches the cell type with its function and layer?
A) Dendritic (Langerhans) cells — touch receptors in the stratum basale
B) Melanocytes — pigment-producing cells located in the stratum basale
C) Keratinocytes — immune defense cells in the stratum spinosum
D) Tactile (Merkel) cells — immune cells scattered in the stratum corneum
B, Melanocytes, found in the stratum basale, produce melanin that protects DNA from UV damage.
Which structure functions as the integrating (control) center in a homeostatic feedback loop?
A) The muscle carrying out a response
B) The brain processing sensory information and directing a response
C) The skin receptor detecting a temperature change
D) The blood vessel dilating during heat loss
B, The control center (often the brain) interprets input from receptors and sends commands to effectors to restore balance.
A molecule is broken down into smaller molecules by adding water. What type of reaction is this?
A) Dehydration synthesis
B) Hydrolysis
C) Exchange reaction
D) Synthesis reaction
B, Hydrolysis uses water to break down polymers into monomers, which happens during digestion.
During anaphase of mitosis, what event marks the separation of sister chromatids?
A) Chromosomes line up along the equator of the spindle.
B) The nuclear envelope breaks apart.
C) Cohesin molecules are degraded by separase, allowing chromatids to move toward opposite poles.
D) Microtubules begin forming from the centrioles.
C, In anaphase, the enzyme separase breaks down cohesin, allowing chromatids to separate and migrate toward opposite poles.
During inflammation, which connective tissue type plays the greatest role in holding fluid and providing a site for immune defense?
A) Loose areolar connective tissue
B) Adipose connective tissue
C) Dense irregular connective tissue
D) Reticular connective tissue
A, Areolar tissue holds interstitial fluid and supports immune activity by hosting macrophages and white blood cells.
Which gland type becomes active during puberty and secretes a thicker, milky sweat containing fatty acids that may lead to body odor when decomposed by bacteria?
A) Merocrine (eccrine) sweat glands
B) Sebaceous glands
C) Apocrine sweat glands
D) Ceruminous glands
C, Apocrine glands open into hair follicles in the axilla, groin, and areola. Their secretion contains fatty acids and proteins, and bacterial action can cause bromhidrosis (body odor).
In the abdominopelvic cavity, the peritoneum is the serous membrane that:
A) Covers the brain and spinal cord
B)Lines the thoracic cavity
C) Surrounds the lungs only
D) Lines and covers organs like the liver, stomach, and intestines
D, The peritoneum lines the abdominopelvic cavity and covers most digestive organs.
When table salt (NaCl) dissolves in water, it separates into Na⁺ and Cl⁻. What type of bond held these atoms together before dissolving?
A) Hydrogen bond
B) Nonpolar covalent bond
C) Polar covalent bond
D) Ionic bond
D, Ionic bonds form when one atom donates electrons to another, creating oppositely charged ions that attract—like Na⁺ and Cl⁻.
Which of the following organelles is involved in autophagy and autolysis?
A) Ribosome
B) Lysosome
C) Mitochondrion
D) Peroxisome
B, Lysosomes contain digestive enzymes that recycle worn-out organelles (autophagy) or self-destruct the cell when needed (autolysis).
A cartilage injury that takes a long time to heal is due to which physiological characteristic of cartilage tissue?
A) Presence of osteocytes that slow repair
B) Collagen deficiency reducing tissue density
C) Avascularity limiting nutrient and oxygen supply to chondrocytes
D) Abundance of fibroblasts and high vascularity
C, Because cartilage lacks blood vessels, nutrients diffuse slowly, which makes repair very slow.
A patient shows yellowing of the skin and eyes (jaundice). Which physiological problem is most likely the cause?
A) Deficiency of oxygen in circulating blood
B) Excess bilirubin due to liver dysfunction
C) Genetic lack of melanin due to a defective tyrosinase enzyme
D) Dilated blood vessels from heat exposure
B, Jaundice results from bilirubin buildup in the blood caused by liver failure, hepatitis, or bile obstruction.
A patient has a burn on the anterior surface of the right forearm. Which of the following correctly describes the location of the injury?
A) On the back of the right arm near the shoulder
B) On the front of the right arm between the elbow and wrist
C) On the back of the forearm below the elbow
D) On the inner side of the upper arm
B, “Anterior” means toward the front, and the forearm is the region between the elbow and wrist. Therefore, the injury is on the front of the right forearm.
Which statement correctly describes the valence shell of an atom?
A) It always contains exactly eight electrons.
B) It determines how the atom will chemically react with other atoms.
C) It is found in the nucleus with protons and neutrons.
D) It controls the number of neutrons in the atom.
B, The valence shell is the outermost electron shell, and its electrons (valence electrons) determine the atom’s chemical reactivity.
Which cytoskeletal component is made of 13 parallel strands of tubulin and is responsible for maintaining cell shape and forming structures like centrioles and spindle fibers?
A) Microfilaments
B) Intermediate filaments
C) Microtubules
D) Actin filaments
C, Microtubules are hollow cylinders composed of 13 protofilaments made of tubulin, providing structural support and aiding in mitotic spindle formation.
The rhythmic contractions of the digestive tract that move food along are mainly controlled by which tissue type, and what is its physiological control mechanism?
A) Dense regular connective tissue – reflex control
B) Cardiac muscle – involuntary, pacemaker cells
C) Skeletal muscle – voluntary, somatic control
D) Smooth muscle – involuntary, autonomic control
D, Smooth muscle, found in the walls of hollow organs, contracts involuntarily under autonomic nervous control, moving materials through organs.
Basal cell carcinoma arises from which specific epidermal layer, and why is early treatment crucial?
A) Stratum spinosum; it spreads rapidly to lymph nodes
B) Stratum basale; it can invade deeper tissues if untreated
C) Stratum corneum; it easily metastasizes
D) Stratum granulosum; it is resistant to radiation therapy
B, Basal cell carcinoma (BCC) develops from stem cells of the stratum basale. It rarely metastasizes but can invade nerves and bone, causing disfigurement if not treated early.