1 Which event listed below occurs first in fertilization ?
A the slow block to polyspermy
B the cortical reaction
C the entry of sperm DNA into the egg
D the acrosomal reaction
E fast block to polyspermy
2 Once an egg has been fertilized, what event(s) are crucial for preventing additional sperm from fertilizing the egg?
A the acrosomal reaction
B the fast block to polyspermy
C both the cortical reaction and fast block to polyspermy
D both the acrosomal and cortical reactions
E the cortical reaction
3 The primitive streak in chick gastrulation is the functional equivalent of
A the notochord in a mammal.
B the archenteron in a frog.
C polar bodies in a sea urchin.
D neural crest cells in a mammal.
E the lip of the blastopore in the frog.
4 Which of the following is TRUE of fate mapping?
A It assesses the quality of a developing embryo.
B It determines the ultimate structure/function of a particular cell type during embryonic development.
C It determines hereditable disorders in the embryo.
D It maps the genes of an embryo.
E It maps the proteins within a morphogenic field.
5 The central nervous system first forms during
6 How does the vegetal pole differ from the animal pole of a zygote?
A The posterior end of the embryo forms at the vegetal pole.
B The vegetal pole can have a higher concentration of yolk.
C The polar bodies bud from this region
D The animal pole cells undergo mitosis but not cytokinesis.
E The blastomeres originate only in the vegetal pole.
7 The ____________________________________________________ is the embryonic tissue in which the primitive streak forms
_____________________________ is a process that results in the establishment cell fate?
8 Human eggs undergo holoblastic cleavage during development.
9 In _____________________________ neighboring cells give "instructions" to influence the development of a cell
10 Which of the following is TRUE of a morphogen? It is a signaling molecule that
A is produced as a gradient & is required for cell-to-cell contact within the embryo.
B is produced as a gradient & induces the differentiation of cells within the embryo.
C that separates out cytoplasmic factors to their respective cells within the developing embryo.
D induces blastulation of the developing embryo.
E induces implantation of the embryo into the uterus of mammals.
Answer 1:- D) The acrosomal reaction
sperm must first fuse with the plasma membrane and then penetrate the female egg cell in order to fertilize it during fertilization. penetrating through the egg's hard shell or extracellular matrix can cause more of a problem to the sperm than fusing to the egg cell which cause little problem. so sperm cells has to pass through the acrosome reaction process which is the reaction that take placein the acrosome of the sperm as it approaches the egg. The acrosome is a cap-like structure present over the anterior half of the sperm's head. This event occurs first in the fertilization out of all mentioned.
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