DNA and Genetics
Which base pairing is correct in dna?
a. a–c
b. a–t
c. g–t
d. a–u
b.) a-t"
Which junction seals intercellular space like a zipper?
tight junction
Which pigment is most responsible for normal variation in skin color?
melanin
What is the S phase of interphase responsible for?
DNA replication
What epidermal layer is only found in thick skin?
a) stratum basale
b) stratum lucidum
c) stratum granulosum
d) stratum spinosum
b) stratum lucidum
Which RNA type carries amino acids to the ribosome during translation?
trna
Gap junctions are formed by proteins called:
connexons
What causes jaundice?
a) excess melanin
b) bilirubin buildup
c) carotene accumulation
d) lack of hemoglobin
b) bilirubin backup
At metaphase, chromosomes are:
aligned at the equator
Keratinocytes are produced by mitosis in which layer?
stratum basale
During transcription, what happens when RNA polymerase encounters adenine (a) on the DNA strand?
It adds U
Which gland uses holocrine secretion?
a) sweat gland
b) salivary gland
c) sebaceous gland
d) pancreas
c) sebaceous gland
Which layer of the epidermis produces the waterproofing barrier by releasing lipid mixtures?
Stratum granulosum
Cytokinesis occurs primarily through:
a) spindle fibers
b) cleavage furrow formed by actin and myosin
c) nucleolus disintegration
d) histone unwinding
b) cleavage furrow formed by actin and myosin
Which gland produces earwax?
ceruminous gland
What ensures DNA replication accuracy by proofreading new strands?
DNA polymerase
Which of the following is an endocrine gland?
a) sweat gland
b) salivary gland
c) pancreas (hormone-secreting cells)
d) sebaceous gland
c) pancreas (partially endocrine)
Which pigment gives a yellowish hue to the skin when it accumulates in the stratum corneum and subcutaneous fat?
carotene
During telophase, which event marks the re-establishment of normal nuclear function?
nuclear envelope re-forms around chromosome clusters
Which skin cancer type is most lethal due to metastasis?
malignant melanoma
What is the role of chaperone proteins in protein synthesis?
They guide proper protein folding and prevent misfolding
Which secretion method involves lipid droplets budding off the cell surface?
a) apocrine
b) eccrine
c) holocrine
d) merocrine
a) apocrine
Which diagnostic condition is characterized by complete absence of melanin due to a genetic defect?
albinism
Why is semiconservative replication important?
preserves one old strand to minimize mutations
Which physiological threat is the primary cause of death in patients with extensive third-degree burns?
fluid loss, infection, eschar