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1. Pericardium protects the heart. It is double layered peritoneum, having outer fibrous and inner serous pericardium layers. 

2. Fibrous pericardium being tough gives protection to the heart. 

3. Serous pericardium has two layers, parietal and visceral layer or epicardium. 

4. In between these two layers, there is pericardial fluid, which helps to absorb shocks and provide nourishment. 

5. In this way pericardium acts as a defence wall.

1. Atria are receiving chambers, while ventricles are distributing chambers. 

2. The blood is driven out from ventricles. 

3. Ventricles are therefore, strong and with thicker walls. 

4. Atria are thin walled as compared to ventricles.

Answer is Say ‘No’.

The correct answer is A) Lungs.

1. Veins carry blood to the heart. 

2. At that time the backward flow of the blood should be prevented. 

3. Therefore, valves are present in veins.

The veins have valves at regular intervals to prevent backflow of blood as blood flows through veins with low pressure.

1. Arteries have relatively thick walls to enable them to withstand the high pressure of blood ejected from the heart. 

2. Arteries expand when the pressure increases as the heart pushes blood out but then recoil (shrink) Wn the pressure decreases when the heart relaxes between heartbeats. 

3. This expansion and recoiling occurs to maintain a smooth blood flow. 

4. Veins, on the other hand, have thinner walls and larger lumen veins have no need for thick walls as then need not have to withstand high pressure like arteries. 

5. Moreover, as veins transport relatively ow pressure blood, they are commonly equipped with valves to promote the unidirectional flow of blood towards the heart.

Correct option is (a) two

1. The transplanted heart beats at higher rate than normal (about 100 to 110 beats per minute) because the nerves leading to the heart are cut during the operation. These nerves stimulate the pacemaker i.e. Sinoatrial node. 

2. The new heart also responds more slowly to exercise and does not increase its rate as quickly as before.

Veins : They carry blood with more carbon dioxide from the body parts to the heart.

Haemoglobin : A red protein responsible for transporting oxygen in the blood of vertebrates.

Haemoglobin acts as a carrier for oxygen and carbon dioxide and plays a key role in respiration. 

1. Haemoglobin is a respiratory pigment present in cytoplasm of RBCs. About 97% of oxygen is transported by these haemoglobin molecules from lungs to tissues. 

2. Haemoglobin has a high affinity for Oa and combines with it to form oxyhaemoglobin. One molecule of Hb has four FeT, each of which can pick up a molecule of oxygen (O₂ ). Hb + 4O₂ → Hb (4O₂ ) 

3. Oxyhaemoglobin is transported from lungs to the tissues where it readily dissociates to release O₂ . Hb (4O₂ ) → Hb + 4O₂ 

4. In the alveoli where PPOa is high and PPCO₂ is low, oxygen binds with haemoglobin, but in tissues, where PPO₂ is lower and PPCO₂ is high, Oxyhaemoglobin dissociates and releases O₂ for diffusion into the tissue cells.

1. Large animals have various organ systems which always work in a coordinated manner. 

2. These animals provide large respiratory surfaces (numerous alveoli) for the exchange of gases. But these respiratory gases must be carried to the cells of tissues which are away from the respiratory surfaces. 

3. To carry these gases to tissues, there is need of transport system. These gasses are transported from respiratory surfaces to the cells of tissues through blood as a transporting medium.

4. Therefore, large animals cannot carry out respiration without the help of circulatory system.

Correct option is (a) Larynx

Average RBC count in adult human is 5.1 to 5.8 million per cubic mm and average total WBC count in adult human is 5000 to 9000 per cubic mm.

1. The normal haemoglobin in adult male is 13-18 mg/100 ml of blood. 

2. In a normal adult female, it is about 11.5-16.5 mg/100 ml of blood. 

3. In anaemic individuals there is lesser amount of haemoglobin. 

4. Functions of haemoglobin is to transport oxygen from lungs to tissues and carbon dioxide from tissues of lungs. 

5. Haemoglobin acts as a buffer and maintains the blood pH.

1. Immunity is the general ability of a body to recognize, neutralize or destroy and eliminate foreign substances or resist a particular infection or disease. 

2. There are two basic types of immunity, viz. innate immunity and acquired immunity, Acquired immunity is further divided into four types, i.e. Natural acquired active immunity, Natural acquired passive immunity, Artificial acquired active passive immunity and Artificial acquired passive immunity.

White blood cells act like police force of our body.

1. The causative pathogen of dengue is dengue virus which induces bone marrow suppression. Since in bone marrow blood cells are formed its suppression causes the deficiency of blood cells leading to low platelet count. 

2. The dengue virus also links with platelets in the blood when there is a virus-specific antibody present in the human body. 

3. When vascular endothelial cell which are infected with dengue virus gets combined with platelets, they tend to destroy platelets. This is one of the major causes of low platelet count in dengue fever. 

4. Even the antibodies that are produced after infection of the dengue virus also cause the destruction of platelets, thus lowering the platelet count.

1. Those who undergo an organ transplant face the possibility that their immune system will reject their new organ and that they will always be at a higher risk for infections. 

2. The immune system is able to recognize the difference between cells that belong to our body and those that do not by learning to identity protein markers (antigens) that are found on cell and infection surfaces. 

3. In people, the antigens or markers that identity their immune system are referred to as the human leukocyte antigen (HLA).

4. Antigens that are recognized as unfriendly invaders stimulate an immune response to destroy them. 

5. Therefore, when organ transplantation is done, the immune responses are temporarily stalled. This helps in acceptance of the graft in the recipient’s body.

1. Microbes have evolved a diverse range of strategies to destroy the host immune system. The protozoan parasite Trypanosoma cruzi and Plasmodium show similar such adaptations to disturb host defence mechanism. 

2. This parasite attacks host tissues including both peripheral and central lymphoid tissues. 

3. This causes systemic acute response in host body which the parasite tries to overcome. The parasite in fact weakens both innate and acquired immunity. 

4. It interferes with the antigen presenting function of dendritic cells via an action on hosts like lectin receptors. These receptors also induce suppression of CD4⁺ T cells responses. Therefore, our immune system fail against such pathogens.

(A) 1/16

When red wheat kernel is crossed with white wheat kernel, the probability of getting red darkest plant is 1/16.

There are three cells enclosed in the male gametophyte of angiosperms out of which two are male gametes and one is tube cell or vegetative cell. The two male gametes are small, round and surrounded by a little cytoplasm. They are situated towards the proximal part of the pollen tube, whereas the tube cell or vegetative cell is irregular in outline and is present in the distal part of the pollen tube. Two male gametes are functional and take part in double fertilization whereas the tube cell / vegetative degenerates after the growth of pollen tube.

Characteristics of Acquired Immunity: 

Pathogen-specific/characterized by memory/ Acquired after the birth of two types Active and passive humoral and cell-mediated includes primary response and secondary response. 

Way by which it can be attained by humans.Active immunity by encountering a pathogen/virulent microbe suffering from contagious disease. passive immunity through immunization readymade antibodies. 

Detailed

Acquired immunity is pathogen-specific. It is not present since birth' It develops.during an individual's lifetime. It is characterized by the memory of the first encounter with the pathogen, which helps in producing intensive secondary response when the pathogen attacks the second time. It has the ability to distinguish different types of foreign molecules or antigens. It is of two types 

(a)Active immunity which develops in the body when it is exposed to the antigens or the pathogens and 

(b) Passive immunity which is bestowed by antibodies directly given to the body.

Active immunity may be attained by the humans by introducing the pathogen either during immunization or by any infection while passive immunity develops by readymade ar.rtibodles e.g. the antibodies received by fetus by mother. The cells which are responsible for producing acquired immune response are T lymphocytes & B-lymphocytes. They produce antibodies which defend the body against the pathogen.

1. A pollen grain consists of two layers viz. outer layer is exine made up of sporopollenin which can tolerate to high temperature, strong acids and alkali. Innerlayer is intine made up of cellulose and pectin. 

2. Exine has microspores at certain places called germpores. 

3. A mature pollen grain has two cells. viz. 

a) Vegetative cells and 

b) Generative cells. 

4. Generative cell divides mitotically to give rise two male gametes.

The correct answer is (A) Maturation

Epidermal cells from the region of maturation form very fine and delicate, thread like structures called root hairs. These root hairs absorb water and minerals from the soil.

Structure of an Ovule ( Megasporangium)

1. The ovule is a small structure attached to the placenta by a stalk called funicle. The body of ovule fuses with funicle at Hilium. 

2. Each ovule consists of one or two protective envelopes called integuments. Enclosed within the integuments a mass of cells called Nucellus which have abundant reserve food materials and provide nourishment to embryo sac. 

3. Inside Nucellus a sac like structure is present which is called embryo sac. 

4. The ovule has a minute aperture called micropyle. 

5. The basal part of ovule opposite to micropyle is called chalaza. 

6. A matured embryosac has * cell, 3 at micropylar end, 2 in the middle and 3 at chalazal end. 

7. The middle two cells are called central cells (polar nuclei) 

8. The three cells at micropylar end constitute egg apparatus which has two synergids and one egg cell.

One type by AABBCCDD & 16 type by individual Aa Bb Cc Dd (2⁴ = 16).

The parental types appear in F₂ generation with out any change. He chose characters that were not linked.

i. ‘K’ stands for carrying capacity. Carrying capacity is defined as the maximum number of individuals of a population that can be sustained by the given habitat/environment. 

ii. Curve ‘b’ is more realistic.

iii. Curve ‘a’. When the predators are absent, the prey population grows exponentially.

(i) It is a polygenic inheritance. It is a quantitative inheritance. The skin colouration is due to additive effect of dominant genes. 

(ii) (a) understanding 

(b) awareness 

(c) Compassion 

(d) Sensitivity towards her companions

Law of Independent Assortment : It states that when two pairs of contrasting traits are combined in a hybrid, segregation of contrasted one pair of character is independent of the other pair of characters.

Detailed answer:

Law of Independent Assortment : It states that when two individuals differing in two pairs of contrasting characters are crossed the segregation of one pair of character into 3 : 1 ratio is independent of the segregation of another pair of contrasting characters into 3 : 1 ratio and also some non parental new recombination of character also appear in the ratio of 9 : 3: 3 : 1 in F₂ generation as shown in the above cross. This is because the alleles of different characters are located on different pairs of homologous chromosomes and that they are independent from one another in their segregation during gamete formation.

Embryo has (trisomy of sex chromosome) XX / Klinefelter's syndrome.

Advised MTP since child will have the following problems.

Male with feminine traits / like gynecomastia / under developed testes / sterile.

RNA is the genetic material in retrovirus. This RNA forms DNA by the process of reverse transcription with the help of the enzymes is called reverse-transcriptase.

(a) Blood to be transfused should be first tested for HIV 

(b) The injections or the needles to be used should be clean, new and sterile. 

(c) Presence of other contamination in the blood should also be checked. 

(d) Donor's and recipient's blood groups (ABO as well as Rh) should be checked and cross-matching should be done to exclude mismatching of blood groups.

(a) Reduce air pollution, improve exposure./sensitivity of the children to the environment to reduce vulnerability, improve resistance, improve food habits, resulting in good health, introduce physical exercise (any other appropriate measure).

(b) Mites in dust pollen, animal dander. 

Immune system respond by producing antibodies of lgE type, inducing Mast cells release chemicals like histamine/serotonin in response to allergens.

As A = 30%

T = 30% (as A = T)

A + T = 60%

G + C = 100-60 = 40%

C (Cytosine) = 4% = 20% (as C = G)

Capping occurs at 5′-end and tailing occurs at 3′-end.

Light stained-loosely packed-Euchromatin. 

Dark stained-densely packed-Heterochromatin 

Euchromatin - transcriptionally active 

Heterochromatin - transcriptionally inactive

Detailed answer:

Euchromatin is lightly stained, diffused but narrow fibrous part of chromatin. It is normal chromatin which possesses active genes. It is transcriptionally active. During nuclear division it replicates normally. It is formed through loose spiralization of nucleosome strands. 

Heterochromatin is darkly stained granular part of chromatin and is formed by solenoid type of coiling of nucleosomes. Transcription does not occur in it. Active genes are absent in it.

hnRNA undergoes splicing in order to remove introns which are intervening or non-coding sequences and exons are joined to form functional mRNA.

‘Tailing’ of hnRNA takes place during conversion of hnRNA into functional mRNA after transcription. It takes place at the 3′-end.

In a nucleosome, the negatively charged component is DNA and positively charged component is histone octamer.

 HIV shows reverse transcription, i.e., formation of DNA on RNA template.

‘a’ is phosphate group and ‘b’ is purine (adenine/guanine).

Capping and tailing.

DNA dependent DNA polymerase. It catalyses polymerisation in 5’ → 3’ direction only

In HIV single stranded RNA is converted to double stranded DNA.