Zoology-SPSC-Practice-6

Practice questions

1. During skeletal muscle contraction, calcium ions bind to which protein to initiate the exposure of actin's myosin-binding sites?
   • Tropomyosin
   • Troponin
   • Myoglobin
   • Titin
2. At the neuromuscular junction, which neurotransmitter is released by motor neurons?
   • Dopamine
   • Serotonin
   • Acetylcholine
   • Noradrenaline
3. Which cells of the alveoli produce pulmonary surfactant?
   • Type I pneumocytes
   • Type II pneumocytes
   • Alveolar macrophages
   • Endothelial cells
4. The Bohr effect describes the influence of increased carbon dioxide and hydrogen ion concentration on:
   • Oxygen affinity of haemoglobin
   • Production of red blood cells
   • Platelet aggregation
   • Formation of plasma proteins
5. Which hormone stimulates the thyroid gland to release thyroxine?
   • Adrenocorticotropic hormone
   • Thyroid-stimulating hormone
   • Follicle-stimulating hormone
   • Growth hormone
6. Which hormone is primarily responsible for increasing blood calcium levels by stimulating bone resorption?
   • Calcitonin
   • Parathyroid hormone
   • Melatonin
   • Aldosterone
7. Which blood component is converted into fibrin during the final stages of blood coagulation?
   • Albumin
   • Fibrinogen
   • Haemoglobin
   • Globulin
8. Which cells in the testes support and nourish developing sperm cells?
   • Leydig cells
   • Sertoli cells
   • Spermatogonia
   • Peritubular myoid cells
9. Which cells of the testes produce testosterone?
   • Sertoli cells
   • Leydig cells
   • Spermatids
   • Spermatocytes
10. In the human menstrual cycle, ovulation is most directly triggered by a surge in:
    • Progesterone
    • Prolactin
    • Luteinizing hormone
    • Oxytocin
11. The acrosome of a mammalian sperm cell contains enzymes that help in:
    • Producing ATP
    • Penetrating the egg's protective coverings
    • Synthesizing DNA
    • Forming the sperm tail
12. Which embryonic process establishes the three primary germ layers?
    • Cleavage
    • Gastrulation
    • Organogenesis
    • Implantation
13. Neural crest cells contribute to the development of which structure?
    • Adrenal medulla
    • Liver parenchyma
    • Pancreatic acini
    • Intestinal epithelium
14. In population genetics, the founder effect occurs when:
    • A population experiences random changes in allele frequencies after being established by a small group
    • Natural selection always eliminates recessive alleles
    • All individuals in a population become genetically identical
    • Mutation stops occurring in a population
15. Which type of evolutionary evidence involves similarities in structures inherited from a common ancestor?
    • Analogous structures
    • Homologous structures
    • Vestigial mutations
    • Acquired characteristics
16. In cladistic analysis, a shared derived character is called a:
    • Plesiomorphy
    • Synapomorphy
    • Autapomorphy
    • Homoplasy
17. Which organ is responsible for producing sound in birds?
    • Syrinx
    • Larynx
    • Pharynx
    • Tracheal pouch
18. Which type of fat is particularly important for heat production without shivering in many mammals?
    • White adipose tissue
    • Brown adipose tissue
    • Cartilage tissue
    • Fibrous connective tissue
19. In cephalopod molluscs such as octopuses, the circulatory system is:
    • Open
    • Closed
    • Absent
    • A combination of open and closed systems
20. In echinoderm development, the adult body plan is generally:
    • Bilaterally symmetrical
    • Pentaradially symmetrical
    • Spherically symmetrical
    • Asymmetrical