21.

Which one of the following cellular parts is correctly described?

• Thylakoids - flattened membranous sacs forming the grana of chloroplasts

• Centrioles - sites for active RNA synthesis

• Ribosomes - those on chloroplasts are larger (80s) while those in the cytoplasm are smaller (70s)

• Ribosomes - those on chloroplasts are larger (80s) while those in the cytoplasm are smaller (70s)

Identify the meiotic stage in which the homologous chromosomes separate while the sister chromatids remain associated at their centromeres

• metaphase I

• metaphase II

• anaphase I

• anaphase I

Which one of the following biomolecules is correctly characterised?

• Lecithin – A phosphorylated glyceride found in cell membrane

• Palmitic acid – An unsaturated fatty acid with 18 carbon atoms

• Adenylic acid – adenosine with a glucose phosphate molecule

• Adenylic acid – adenosine with a glucose phosphate molecule

Given below is the diagrammatic sketch of a certain type of connective tissue. Identify the parts labelled A, B, C and D, and select the right option about them.

• Part A	Part B	Part C	Part D
  Macrophage	Fibroblast	Collagen fibres	Mast cells

• Part A	Part B	Part C	Part D
  Mast cell	Macrophage	Fibroblast	Collagen fibres

• Part A	Part B	Part C	Part D
  Macrophage	Collagen fibres	Fibroblast	Mast cell

• Part A	Part B	Part C	Part D
  Macrophage	Collagen fibres	Fibroblast	Mast cell

Which one of the following options gives the correct categorisation of six animals according to the type of nitrogenous wastes (A, B, C), they give out?

• A Ammonotelic	B Ureotelic	C Uricotelic
  Pigeon, Humans	Aquatic Amphibia, Lizards	Cockroach, Frog

• A Ammonotelic	B Ureotelic	C Uricotelic
  Frog, Lizards	Aquatic Amphibia, Humans	Cockroach, Pigeon

• A Ammonotelic	B Ureotelic	C Uricotelic
  Aquatic Amphibia	Frog, Humans	Pigeon, Lizards, Cockroach

• A Ammonotelic	B Ureotelic	C Uricotelic
  Aquatic Amphibia	Frog, Humans	Pigeon, Lizards, Cockroach

Which one of the following pairs of chemical substances, is correctly categorised?

• Calcitonin and thymosin - Thyroid hormones

• Pepsin and prolactin - Two digestive enzymes secreted in stomach

• Troponin and myosin - Complex proteins in striated muscles

• Troponin and myosin - Complex proteins in striated muscles

The supportive skeletal structures in the human external ears and in the nose tip are examples of

• ligament

• areolar tissue

• bone

• bone

The four sketches (A, B, C and D) given below, represent four different types of animal tissues. Which one of these is correctly identified in the options given, along with its correct location and function?

• Tissue	Location	Function
  Glandular epithelium	Intestine	Secretion

• Tissue	Location	Function
  Collagen fibres	Cartilage	Attach skeletal muscles to bones

• Tissue	Location	Function
  Smooth muscle tissue	Heart	Heart contarction

• Tissue	Location	Function
  Smooth muscle tissue	Heart	Heart contarction

A fall in glomeruclar filtration rat (GFR) activates

• Juxtra glomerular cells to release renin

• Adrenal cortex to release aldosterone

• Adrenal medulla to release adrenaline

• Adrenal medulla to release adrenaline

Which one of the following characteristics is common both in humans and adult frogs?

• Four chambered heart

• Internal fertilisation

• Nucleated RBCs

• Nucleated RBCs