II. Stimulates adrenal gland to release catecholamines into blood circulation
C. Heroin
III. Effective sedative and painkiller
D. Cocaine
IV. A depressant; slows down body function
Nicotine stimulates catecholamine release. Morphine is a sedative and painkiller. Heroin is a depressant. Cocaine causes euphoria and increased energy.
Match List-I with List-II with respect to chronology of evolution of life forms:
List-I
List-II
A. About 65 mya
I. Jawless fish probably evolved
B. About 500 mya
II. The dinosaurs suddenly disappeared from the earth
C. About 350 mya
III. Seaweeds and few plants probably existed
D. About 320 mya
IV. Invertebrates were formed and became active
Dinosaurs disappeared about 65 mya. Invertebrates became abundant about 500 mya. Jawless fishes evolved about 350 mya. Seaweeds and early plants existed about 320 mya.
Progestasert is a hormone-releasing IUD. Multiload 375 is a copper-releasing IUD. Diaphragm is a female barrier contraceptive. Saheli is a non-steroidal oral contraceptive.
The following are the stages of life cycle of Plasmodium. Arrange the stages in the proper order.
(A) The parasites reproduce asexually in RBCs, bursting the cells.
(B) The parasites reproduce asexually in liver cells, bursting the cells and releasing into blood.
(C) Gametocytes develop in RBCs.
(D) Sporozoites reach the liver through the blood.
(E) Female mosquito injects sporozoites into humans during bite.
Choose the correct answer from the options given below:
Female Anopheles injects sporozoites into humans. They first infect liver cells, then RBCs where repeated asexual multiplication occurs, followed by formation of gametocytes.
Match List-I with List-II related to embryonic development at various months of pregnancy:
List-I
List-II
A. The foetus movement starts and hair appears on the head
I. 24 weeks of pregnancy
B. The foetus develops limbs and digits
II. 20 weeks of pregnancy
C. The foetus develops external genital organs
III. 8 weeks of pregnancy
D. The foetus body is covered with fine hair; eyelids separate and eyelashes are formed
IV. 12 weeks of pregnancy
At 8 weeks limbs and digits appear, at 12 weeks external genitalia develop, at 20 weeks foetal movement and scalp hair appear, and by 24 weeks the body is covered with fine hair and eyelashes develop.
Select the incorrect statements from the following:
(A) Digestive system in Platyhelminthes is incomplete.
(B) Bilateral symmetry is a characteristic feature of adult Echinoderms.
(C) Pseudocoelom is possessed by Aschelminthes.
(D) Notochord is persistent throughout life in the class Chondrichthyes.
(E) Members of class Reptilia maintain a constant body temperature.
Choose the correct answer from the options given below:
Adult echinoderms show radial symmetry, not bilateral symmetry. Reptiles are ectothermic and do not maintain a constant body temperature. The other statements are correct.
A group of researchers procured some fish-like animals and upon investigation the following characters were observed:
(A) Endoskeleton was made of cartilage.
(B) Ectoparasitic, as they were found attached on fish skin with their circular sucking mouth.
(C) Paired fins and scales were absent, but seven pairs of gill slits were present.
Which of the following species of animals did they consider to fit best with these characters?
Petromyzon (lamprey) is a jawless cyclostome having a cartilaginous endoskeleton, circular sucking mouth, seven pairs of gill slits and an ectoparasitic mode of life.
Choose the correct statements regarding muscle contraction.
(A) A motor neuron carries a signal sent by the Central Nervous System (CNS) to the sarcolemma of the muscle fibre.
(B) The neural signal generates an action potential which causes the release of Ca++ into sarcoplasm.
(C) Increase in Ca++ inactivates the actin for breaking cross bridges.
(D) Actin binds to the myosin head to form a cross bridge.
(E) Shortening of sarcomere takes place by pulling actin filaments towards the centre of the A band.
Choose the correct answer from the options given below:
Motor neurons transmit impulses to muscle fibres. Ca++ released into the sarcoplasm activates actin by binding troponin. Cross bridges form between actin and myosin, and actin filaments slide towards the centre of the A band. Statement C is incorrect because Ca++ activates, not inactivates, actin.