Edexcel AS Level Biology

1.  In some diploid organisms, haploid cells are produced by meiosis. The diagram shows an animal cell at various stages during the first division of meiosis

(i) Identify the correct sequence in the diagram that shows the first division of meiosis.

 A) 1, 2, 3, 4, 5 

 B) 2, 5, 4, 1, 3 

 C) 3, 2, 4, 1, 5 

 D)  5, 4, 1, 2, 3

(ii) Identify the parts labelled P and Q.

iii) In mammals, meiosis occurs during oogenesis and spermatogenesis. Describe how the products of oogenesis differ from the products of spermatogenesis in mammals.

Answers;

1.i) C) 3, 2, 4, 1, 5

ii) P – nuclear envelope (1) Q– centromere

iii) ova { are larger cells / contain more food stores / contain more cytoplasm } 

• spermatozoa contain an acrosome, ova do not 
• spermatozoa has a ( tail / flagellum / microtubules), ova do not 
• ova are surrounded by the (zona pellucida / other cells), spermatozoa are not 
• oogenesis produces polar bodies, spermatogenesis does not 

Learn more:  Difference between Spermatogenesis and Oogenesis