Download App

MODEL PAPER 7 — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYMODEL PAPER 74 Marks
Question
Read the following text carefully and answer the questions that follow:
A pathogen is defined as an organism causing disease to its host, with the severity of the disease symptoms referred to as virulence. Pathogens are taxonomically widely diverse and comprise viruses and bacteria as well as unicellular and multicellular eukaryotes. The immune system of a person is suppressed. He was found positive for a pathogen in the diagnostic test ELISA.
Image
i. Name the disease, the patient is suffering from. (1)
ii. Which pathogen is identified by ELISA test? (1)
iii. Which cells of the body are attacked by the pathogen? (2)
OR
Suggest preventive measures of the infection. (2)
✓

Answer

i. The patient is suffering from AIDS (Acquired Immuno Deficiency Syndrome).
ii. HIV (Human Immunodeficiency Virus) identified by the ELISA.
iii. Helper T-cells, macrophages, B-lymphocytes are attacked by the pathogen.
OR
Preventive measures:
a. People should be educated about AIDS transmission.
b. Disposable needles and syringes should be used.
c. Sexual habits should be changed immediately.
d. High-risk groups should be discouraged from donating blood.
e. Routine screening may be done.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Case study (4 Marks)" from MODEL PAPER 7→MODEL PAPER 7 — all question types→BIOLOGY STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

Read the following and answer any four questions from (i) to (v) given below:

ln many species of fig trees, there is a tight one-to-one relationship with the pollinator species of wasp. It means that a given fig species can be pollinated only by its 'partner' wasp species and no other species. The wasp pollinates the fig inflorescence while looking for suitable egg-laying sites. ln return for the favour of pollination, the fig offers the wasp some of its developing seeds as food for the developing wasp larvae.

  1. The interaction between fig trees and wasp is an example of:
  1. Mutualism
  2. Commensalism
  3. Amensalism
  4. Parasitism
  1. AD the given interactions are similar to interaction between fig trees and wasp, except.
  1. Plant and animal relation for pollination.
  2. Association of algae and fungi in lichens.
  3. Association of cattle egret and grazing cattle.
  4. Association of fungi and roots of higher plants in mycorrhiza.
  1. In which of the following interactions both partners are adversely affected?
  1. Parasitism
  2. Mutualism
  3. Competition
  4. Predation
  1. ln relationship between fig and wasp:
  1. One benefitted other harmed.
  2. Both are benefitted.
  3. One benefitted other unaffected.
  4. One inhibited, other unaffected.
  1. Assertion: Fig and wasp cannot complete their life cycle without each other.

Reason: They show mutualistic relationship.

  1. Both assertion and reason are true and reason is the correct explanation of assertion.
  2. Both assertion and reason are true but reason is not the correct explanation of assertion.
  3. Assertion is true but reason is false.
  4. Both assertion and reason are false.
→
Explain population attributes.
→
A regulatory body working under MoEF for the release of transgenic crop is ____________:
  1. NBPGR
  2. NSC
  3. NIPGR
  4. GEAC
→
Explain any two X-linked recessive disorder?
→
Discuss the important measures that are useful in preventing and controlling the use of alcohol and drugs in youth.
→
Differentiate between following.
→
Read the following and answer any four questions from 2(i) to 2(v) given below:

Restriction endonuclease was isolated for the first ti me by W. Arb er in 1962 in bacteria. Restriction endonucleases cut the DNA duplex at specific points therefore they are also called as molecular scissors or biological scissors. Three types of restriction endonucleases are Type I, Type II and Type III but only Type II restriction endonucleases are used in recombinant DNA technology. Restriction endonuclease EcoR I recognises the base sequence GAATTC in DNA duplex and cut strands between G and A.

  1. Only type II restriction enzymes are used in gene manipulation because
  1. ATP is not required for cleaving.
  2. It consists of three different subunits.
  3. It makes cleavage or cut in both the strands of DNA molecule.
  4. Both (a) and (c).
  1. Which of the following ions are used by restriction endonucleases for restriction?
  1. Mg2+ ions
  2. Mn2+ ions
  3. Na2+ ions
  4. K2+ ions
  1.  Restriction endonuclease was isolated for the first time in a:
  1. Plant cell.
  2. Animal cell.
  3. Prokaryotic cell.
  4. Genninal cell.
  1. Restriction endonucleases are also called as molecular or biological scissors because,
  1. They cleave base pairs of DNA only at their terminal ends.
  2. They cleave one or both the strands of DNA.
  3. They act only on single stranded DNA.
  4. None of these.
  1. Select the option that correctly states the working action of restriction endonuclease EcoR I on DNA sequence GAATTC

  1. $\ \ \ \ \ \ \ \ \ \ \ \ \downarrow\\5'-\text{GAATTC}-3'\\3'-\text{CTTAAG}-5'\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \uparrow$

  2. $ \ \ \ \ \ \ \ \ \ \ \downarrow\\5'-\text{GAATTC}-3'\\3'-\text{CTTAAG}-5'\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \uparrow$

  3. $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \downarrow\\5'-\text{GAATTC}-3'\\3'-\text{CTTAAG}-5'\\\ \ \ \ \ \ \ \ \ \uparrow$

  4. $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \downarrow\\5'-\text{GAATTC}-3'\\3'-\text{CTTAAG}-5'\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \uparrow$

→
Read the following and answer any four questions from (i) to (v) given below:

Saurin, a M.Sc student, get an assignment on sewage treatment plant (STP) to study the microbial load. After visiting such plant in his locality, he makes a simplified diagram of the STP for his project. Study the diagram given below and answer the following questions.

  1. In the diagram 'A' denotes:
  1. Aeration tank.
  2. Primary settling tank.
  3. Secondary settling tank.
  4. Sludge digester.
  1. Which of the following is incorrect regarding the sludge released from A?
  1. It is formed after primary treatment.
  2. It does not require aeration.
  3. It possesses floes of decomposer microbes.
  4. It is used in landfills.
  1. A large number of aerobic heterotrophic microbes grow in:
  1. A
  2. B
  3. C
  4. Both (a) and (b).
  1. What is denoted by 'D' in the given diagram?
  1. Primary sludge.
  2. Primary effluent.
  3. Activated sludge.
  4. Secondary effluent.
  1. Assertion: The colloided and finely suspended matter of sewage form aggregates which are called floes.

Reason: Floes contain masses of bacteria, slime and fungal filaments.

  1. Both assertion and reason are true and reason is the correct explanation of assertion.
  2. Both assertion and reason are true but reason is not the correct explanation of assertion.
  3. Assertion is true but reason is false.
  4. Both assertion and reason are false.
→
Describe: Genetic engineered insulin
→
Read the following and answer any four questions from (i) to (v) given below:
Wetlands are called Ramsar sites because the first international convention on their conservation was held in Ramsar in Iran in 1971. Wetlands or Ramsar sites are low lying marshy areas which get filled up during rains due to runoff and overflow from other water bodies. They are often considered to be waste lands which are used as dumping areas and filled up to recover land for various constructions activities. As a result, a large number of wetlands have disappeared.
  1. Select the incorrect match of wetland and its location.
 
Wetland
Location
(a)
Harike
Punjab
(b)
Chandra Tai
H.P.
(c)
Bhoj
M.P.
(d)
Ashtamudi
Odisha
  1. Migratory bird flamingo breeds in which of the following wetlands?
  1. Bhitarkanika Mangroves.
  2. Rann of Kutch.
  3. Harike.
  4. Chandra Tal.
  1. Which of the following is not an importance of wetlands?
  1. They are an important source of recharging groundwater.
  2. They provide protection from floods.
  3. They are good source of siltation and purification of water.
  4. None of these.
  1. Which of the following wetland ecosystem is highly acidic and has a accumulation of decomposed plants known as peat?
  1. Bog
  2. Mangrove
  3. Estuary
  4. Watershed
  1. The mangroves of Bhitarkanika are famous for:
  1. Rare migratory waterbirds.
  2. Nesting sites for endangered olive ridley turtles.
  3. Prawn cultivation.
  4. All of these.
→