Which of the following is a characteristic of steroid hormones?
A) Stored in vesicles before release
B) Synthesized on demand
C) Highly water-soluble
D) Bind to membrane receptors only
📖 شرح: Steroid hormones are synthesized when needed because they cannot be stored.
الإجابة الصحيحة: B
Which process is essential for steroid hormone excretion?
A) Phosphorylation
B) Conjugation in the liver
C) Binding to ribosomes
D) Conversion to amino acids
📖 شرح: Steroid hormones undergo conjugation to increase water solubility for excretion.
الإجابة الصحيحة: B
Which structure carries genetic information from parents to offspring?
A) Proteins
B) DNA
C) Lipids
D) Carbohydrates
📖 شرح: DNA contains hereditary genetic information.
الإجابة الصحيحة: B
Which type of cell division produces gametes?
A) Mitosis
B) Meiosis
C) Binary fission
D) Budding
📖 شرح: Meiosis produces haploid gametes for reproduction.
الإجابة الصحيحة: B
Which chromosome pair determines genetic sex in humans?
A) Chromosome 1
B) Chromosome 10
C) X and Y chromosomes
D) Mitochondrial DNA
📖 شرح: Sex is determined by the X and Y chromosomes.
الإجابة الصحيحة: C
Which genetic disorder is caused by an extra copy of chromosome 21?
A) Turner syndrome
B) Down syndrome
C) Klinefelter syndrome
D) Edwards syndrome
📖 شرح: Down syndrome results from trisomy 21.
الإجابة الصحيحة: B
Which term describes different versions of the same gene?
A) Alleles
B) Ribosomes
C) Chromatids
D) Centrioles
📖 شرح: Alleles are alternative forms of a gene.
الإجابة الصحيحة: A
Which of the following is inherited exclusively from the mother?
A) Y chromosome
B) Mitochondrial DNA
C) Autosomal genes
D) X-linked recessive traits
📖 شرح: Mitochondrial DNA is maternally inherited.
الإجابة الصحيحة: B
Which process increases genetic variation during meiosis?
A) DNA replication
B) Crossing over
C) Cytokinesis
D) Protein synthesis
📖 شرح: Crossing over exchanges genetic material between homologous chromosomes.
الإجابة الصحيحة: B
Which condition results from a mutation in a single gene?
A) Polygenic disorder
B) Monogenic disorder
C) Chromosomal nondisjunction
D) Epigenetic modification
📖 شرح: Monogenic disorders arise from mutations in one gene.
الإجابة الصحيحة: B
Which term describes the observable characteristics of an individual?
A) Genotype
B) Phenotype
C) Karyotype
D) Haplotype
📖 شرح: Phenotype refers to observable traits influenced by genes and environment.
الإجابة الصحيحة: B
Which technique is used to visualize chromosome number and structure?
A) PCR
B) Karyotyping
C) Western blotting
D) ELISA
📖 شرح: Karyotyping displays chromosome structure and detects abnormalities.
الإجابة الصحيحة: B
Which structure gives rise to the bipotential gonad in the embryo?
A) Mesonephros
B) Gonadal ridge
C) Neural crest
D) Somites
📖 شرح: The gonadal ridge forms the bipotential embryonic gonad.
الإجابة الصحيحة: B
Which gene is essential for testis development?
A) SOX9
B) WNT4
C) FOXL2
D) RSPO1
📖 شرح: SOX9 promotes Sertoli cell differentiation and testis formation.
الإجابة الصحيحة: A
Which chromosome carries the SRY gene?
A) X chromosome
B) Y chromosome
C) Chromosome 21
D) Chromosome 7
📖 شرح: The SRY gene on the Y chromosome initiates testis development.
الإجابة الصحيحة: B
In the absence of SRY, the gonad develops into:
A) Testis
B) Ovary
C) Adrenal gland
D) Mesonephros
📖 شرح: Without SRY, the default pathway is ovarian development.
الإجابة الصحيحة: B
Which cells are the first to differentiate in the developing testis?
A) Leydig cells
B) Sertoli cells
C) Theca cells
D) Granulosa cells
📖 شرح: Sertoli cells differentiate first and organize testis cords.
الإجابة الصحيحة: B
Which hormone produced by Sertoli cells causes regression of Müllerian ducts?
A) Testosterone
B) AMH
C) DHT
D) Progesterone
📖 شرح: AMH induces Müllerian duct regression in male embryos.
الإجابة الصحيحة: B
Which ducts develop into the male internal reproductive tract?
A) Müllerian ducts
B) Wolffian ducts
C) Neural ducts
D) Branchial ducts
📖 شرح: Wolffian ducts form epididymis, vas deferens, and seminal vesicles.
الإجابة الصحيحة: B
Which hormone stabilizes the Wolffian ducts during male development?
A) Estrogen
B) Progesterone
C) Testosterone
D) Cortisol
📖 شرح: Testosterone maintains Wolffian duct structures.
الإجابة الصحيحة: C