CBSE XII Biology practice questions

Question 1

Which part of the ovule stores reserve food materials?

Accepted Answer

Nucellus

Answer

Integument

Answer

Chalaza

Answer

Hilum

Question 2

Where does fertilization normally take place in the human female reproductive system?

Accepted Answer

Ampullary region of fallopian tube

Answer

Uterine fundus

Answer

Cervical canal

Answer

Infundibulum

Question 3

What is the phenotypic ratio of an F2 generation in a monohybrid cross exhibiting incomplete dominance (e.g. Antirrhinum sp.)?

Accepted Answer

1:2:1

Answer

3:1

Answer

9:3:3:1

Answer

2:1

Question 4

In eukaryotes which RNA polymerase is responsible for the transcription of hnRNA (precursor of mRNA)?

Accepted Answer

RNA Polymerase II

Answer

RNA Polymerase I

Answer

RNA Polymerase III

Answer

RNA Polymerase IV

Question 5

Which hominid ancestor had a brain capacity between 650Ð800 cc and probably did NOT eat meat?

Accepted Answer

Homo habilis

Answer

Homo erectus

Answer

Neanderthal man

Answer

Australopithecines

Question 6

Which property distinguishes normal cells from cancerous cells?

Accepted Answer

Contact inhibition

Answer

Metastasis

Answer

Uncontrolled proliferation

Answer

Telomerase activation

Question 7

During gel electrophoresis DNA fragments move towards the anode because:

Accepted Answer

DNA fragments are negatively charged due to phosphate groups

Answer

DNA fragments are positively charged

Answer

Agarose gel carries a positive charge

Answer

Ethidium bromide imparts a negative charge

Question 8

RNA interference (RNAi) is used to develop pest-resistant tobacco plants against which nematode?

Accepted Answer

Meloidogyne incognita

Answer

Ascaris lumbricoides

Answer

Wuchereria bancrofti

Answer

Ancylostoma duodenale