EMBRIOLOGY
Which structure gives rise to both sperm and oocytes?
a) Somatic cells
b) Primordial germ cells
c) Mesodermal cells
B) Primordial germ cells
Which bone forms the lower jaw?
a) Maxilla
b) Mandible
c) Zygomatic
b) Mandible
Which type of microscope is most commonly used for examining stained tissue sections in histology?
a) Light microscope
b) Transmission electron microscope (TEM)
c) Scanning electron microscope (SEM)
a) Light microscope
Proteins are made of which basic building blocks?
a) Fatty acids
b) Amino acids
c) Monosaccharides
b) Amino acids
Which planet is known as the “Red Planet”?
a) Venus
b) Mars
c) Jupiter
b) Mars
During spermatogenesis, which cell is the first to undergo meiosis I?
a) Spermatogonia
b) Primary spermatocyte
c) Secondary spermatocyte
Primary spermatocyte
Which muscle is responsible for turning the head to the opposite side?
a) Trapezius
b) Sternocleidomastoid
c) Splenius capitis
b) Sternocleidomastoid
Which stain is most widely used in routine histology for general tissue observation?
a) Hematoxylin and eosin (H&E)
b) Periodic acid–Schiff (PAS)
c) Silver stain
a) Hematoxylin and eosin (H&E)
Which type of bond primarily stabilizes the primary structure of a protein?
a) Hydrogen bonds
b) Peptide bonds
c) Disulfide bonds
b) Peptide bonds
Who painted the Mona Lisa?
a) Vincent van Gogh
b) Leonardo da Vinci
c) Pablo Picasso
b) Leonardo da Vinci
Which event occurs during the second week of development?
a) Formation of the bilaminar germ disc
b) Gastrulation begins
c) Neural tube closure
Formation of the bilaminar germ disc
Which cranial nerve provides motor innervation to the muscles of facial expression?
a) Trigeminal nerve (CN V)
b) Facial nerve (CN VII)
c) Glossopharyngeal nerve (CN IX)
b) Facial nerve (CN VII)
Which organelle is responsible for protein synthesis for secretion?
a) Rough endoplasmic reticulum (RER)
b) Smooth endoplasmic reticulum (SER)
c) Lysosome
a) Rough endoplasmic reticulum (RER)
Which level of protein structure describes the 3D folding of a single polypeptide chain?
a) Secondary structure
b) Tertiary structure
c) Quaternary structure
b) Tertiary structure
Which is the largest ocean on Earth?
a) Atlantic Ocean
b) Pacific Ocean
c) Indian Ocean
b) Pacific Ocean
The primitive streak is essential for:
a) Establishing the anterior-posterior body axis
b) Formation of the placenta
c) Differentiation of trophoblast cells
Establishing the anterior-posterior body axis
The carotid sinus, a baroreceptor important for blood pressure regulation, is innervated mainly by:
a) Glossopharyngeal nerve (CN IX)
b) Hypoglossal nerve (CN XII)
c) Vagus nerve (CN X)
a) Glossopharyngeal nerve (CN IX)
In electron microscopy, the plasma membrane appears as a trilaminar structure due to:
a) Carbohydrate coat (glycocalyx)
b) Phospholipid bilayer with associated proteins
c) Microtubule arrangement
b) Phospholipid bilayer with associated proteins
Which type of enzyme inhibition is characterized by the inhibitor binding to the active site, competing with the substrate?
a) Non-competitive inhibition
b) Competitive inhibition
c) Allosteric inhibition
b) Competitive inhibition
Who was the first woman to win a Nobel Prize?
a) Rosalind Franklin
b) Marie Curie
c) Ada Lovelace
b) Marie Curie
Which signaling pathway is most directly involved in the dorsal-ventral patterning of the neural tube?
a) Sonic hedgehog (Shh) and BMP gradients
b) Notch-Delta signaling
c) Wnt/β-catenin pathway
Sonic hedgehog (Shh) and BMP gradients
Which vein is formed by the union of the sigmoid sinus and the inferior petrosal sinus at the jugular foramen?
a) Internal jugular vein
b) External jugular vein
c) Vertebral vein
a) Internal jugular vein
Which cytoskeletal component is mainly responsible for intracellular transport of vesicles and organelles?
a) Actin filaments
b) Intermediate filaments
c) Microtubules
c) Microtubules
In the Michaelis–Menten equation, the Km (Michaelis constant) represents:
a) The maximum velocity of the enzyme-catalyzed reaction
b) The substrate concentration at which the reaction rate is half of Vmax
c) The turnover number of the enzyme
b) The substrate concentration at which the reaction rate is half of Vmax
Which ancient civilization built the city of Machu Picchu?
a) Maya
b) Aztec
c) Inca
c) Inca