What is the function of amniotic fluid? How are substances exchanged between the embryonic and maternal blood?
See Answer →Indicate the following changes that occur during metamorphosis in amphibians either as progressive or regressive or remodeling:
a) The development of middle ear in connection with the pharyngeal pouch.
b) The change in the shape of the mouth and the shortening and reduction of the cloacal tube.
c) Disappearance of lateral line organs of skin and reduction of blood vessels.
d) The differentiation of brain.
e) The changes in the portal system and the changes in the vascular system to supply blood to the lungs.
See Answer →Fill in the blanks with suitable words.
a) ………………. is the extension of egg cytoplasm around the entering sperm head.
b) Inhibitor of microfilament formation such as ……………… prevents the formation of fertilization cone.
c) The early response for the entry of sperm into the egg is prevention of ………………. .
d) The ………………. for polyspermy is mediated by the electrical depolarization of egg plasma membrane.
e) The slow block to polyspermy is achieved by …………… reaction.
See Answer →Chose the correct answer form alternatives provided.
a) Fertilization is responsible for the activation/arrest of development.
b) Activation of the sperm ensures/does not ensure that sperm will meet the egg.
c) In organisms with external/internal fertilization, chemotactic mechanisms have been evolved to attract the sperm towards the egg.
d) A period of maturation in the female reproductive tract required for the transformation of sperm is known as activation/capactiation.
e) Sperm using an enzyme called acrosin/hyaluronidase penetrate their way through zona pellucida.
See Answer →What is a signal transduction pathway? Write out its steps in the order they would occur in a target cell.
See Answer →How is EMT used in the embryo and in the adult?
See Answer →What is the difference between juxtacrine and paracrine signalling.
See Answer →How would you define a ligand in cell-to cell signalling?
See Answer →List at least three stages in gene expression that can be regulated to result in differentiated cell types? Explain any one of them with the help of an example
See Answer →Briefly write the functions of the following hormones secreted in mammals.
a) Adrenocoricotropic hormone
b) Parathormone
c) Aldosterone
d) Testosterone
e) Progesterone
See Answer →How do bats prevent getting deaf from their high frequency calls? How do they get information about the immediate environment?
See Answer →a) In fishes the …………………. covers the brain and spinal cord.
b) Reptiles and birds have a double membrane made up of …………… and …………………. to protect the brain.
c) In lower vertebrates the epithalamus forms …………………. and …………………. .
See Answer →Types of mammalian uteri
See Answer →Kidney blood circulation
See Answer →What are precaval veins?
See Answer →Write one difference between somatic and visceral arteries.
See Answer →How does right subclavian develop in mammals?
See Answer →What is the role of ductus arteriosus in bird’s circulatory system?
See Answer →What is the major modification that occurs in reptilian aortic arches?
See Answer →