CBSE Class 11 Biology Sample Paper

CBSE Class 11 Biology Sample Paper


Class XI Biology

Sample Paper – 1

  1.   Time: 3 hrs                                                                                           Total Marks: 70   

General Instruction:

  1. All questions are compulsory.
  2. The question paper consists of four  sections A,  B,  C  and D.
  3. Internal choice  is  given  in  all  the sections. A  student  has  to  attempt  only  one  of  the alternatives in  such  questions.
  4. Section A contains 5 questions of 1 mark each.
  5. Section B has 7 questions of 2 marks each.
  6. Section C is of 12 questions of 3 marks each.
  7. Section D has 3 questions of 5 marks each.
  8. Wherever necessary, the diagrams drawn should  be neat and  properly labelled.

                                                                     SECTION – A

  1. Define cladistics.


Name two botanical gardens located in India.

  1. What is the main function of sepals?
  2. Can there be mitosis without DNA  replication in the ‘S’ phase?
  3. What does the half-leaf experiment  on photosynthesis indicate?


Who first showed  that  only  the  green parts of  plants could  release  oxygen?

  1. What does the H-zone of a sarcomere in a myofibril contain?

                                                                SECTION – B

  1. What are gemmae? What role does  gemma  play  in  reproduction?
  2. Explain a  competitive inhibitor  with a suitable example.


What  are  fatty  acids?  Give  two  examples  indicating  the  number  of  carbon  atoms         present in  each.

  1. What is  meant  by  vital  capacity?  List  any  two  categories  of  people  who  possess  higher vital capacity.
  2. Where are  myelinated  and  non-myelinated  fibres  commonly  found  in  the  nervous system?
  3. How is a key useful in the identification and  classification of an organism?
  4. List any  two  points  of  differences  between  dicot  stem  and  dicot  root  on  the  basis  of their  vascular bundles.


Below  is the diagram of  lenticels.  Identify  the regions  A,  B,  C  and  D.

  1. Who proposed the  double  helical  model  of  DNA?  Why  are  two  strands  of  DNA  described as antiparallel?

                                                             SECTION – C

  1. What steps would  you  follow  to classify  a specimen?
  2. Describe the structure and functions of  the tracheary elements.


Understand  the given  description and  name the cells or  tissues.

  1. In dicotyledonous plants, it  occurs in  layers below  the epidermis.
  2. Responsible for the radial conduction of  water in plants.
  3. Central lumens are obliterated.


    1. How is a pinnately  compound  leaf  different  from a palmately  compound  leaf?
    2. The transverse section of a plant material shows the  following  anatomical features:
      • The vascular  bundles  are  conjoint,  scattered  and    surrounded  by  a sclerenchymatous bundle sheath.
      • Phloem parenchyma is absent. What will you identify  it  as?

16. Explain with suitable examples the different types of phyllotaxy.


Draw a labelled  diagram  of  the alimentary  canal  of  a cockroach.


    1. What is meant  by  the  dynamic state  of  body  constituents?
    2. Name the form of energy  which  is used  by  living cells.
    3. What is an apoenzyme?
  1. Write any  two  characteristics  of  mitochondria  and  draw  a  labelled  diagram  of  a mitochondrion.
  2. What is the significance  of  meiosis?
  3. Give one  chief  function  and  one  main  deficiency  symptom  for  each  of  the  following  in plants:  Iron,  zinc and phosphorus.


Represent  diagrammatically  the  relationship  between  atmospheric,  soil  and                biomass nitrogen  pools  during  the nitrogen  cycle.

  1. Where does carboxylation take place in a  C3  plant? Explain the process.
  2. Why is the parathyroid hormone  (PTH) considered  a hypercalcaemic  hormone?
  3. Name the  different  types of  teeth and  their  number  in  an  adult human.
  4. List any  three  artificial  or  man-made methods  to overcome seed dormancy.


State  the name of the plant growth regulator  which  you  will use in the following  cases:

  1. To promote  flowering  in  pineapples
  2. To stimulate early  seed  production in  conifers
  3. To sprout potato tubers
  4. To prevent  leaf  drop at an early  age
  5. To prepare weed-free  lawns
  6. To delay  leaf  senescence

                                                         SECTION D

  1. Study the  given  figure  of  the  excretory  system  of  man  carefully  and answer  the following  questions:

    1. Name the parts labelled (a), (b), (c), (d) and  (e).
    2. Give one major  function of  each  of  these parts.


Name  the  components  of  the  formed  elements  in  the  blood  and  mention  one       major function  of  each.

  1. Explain why
    1. Exogenous application of  auxin  fails to enhance  the growth of  intact plants.
    2. Vitamins are not considered plant  growth hormones.
    3. It is appropriate to call a short-day plant  a long-night plant.
    4. Some plants,  belonging  to  halophytes  and  growing  in  marshy  lands,  face  great difficulty  in germination.
    5. Gibberellins do not enhance the growth of  isolated  plant


A portion of  the  cross-section  of  leaf  is shown in the diagram. Answer  the following:

  1. Label 1 to 4.
  2. What kind  of  anatomy  is shown in the diagram?
  3. Write the structure and functions  of  2  and 4.
  1. Explain diagrammatically  the  mechanism  of  breathing  and  the  positions  of  ribs, diaphragms and  the thoracic cavity  during  inspiration and expiration.


What  is  uraemia?  Name  and  describe  the  process  used  to  remove  waste      substances from  individuals suffering  from  uraemia.

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