AHSEC| CLASS 11| BIOLOGY| SOLVED PAPER - 2016| H.S.1ST YEAR

AHSEC| CLASS 11| BIOLOGY| SOLVED PAPER - 2016| H.S.1ST YEAR

2016
Biology
(Theory)
Times: 3 hours
Full marks: 70
 
Part - I (Botany)


1. Define species.      1

Ans:- Species is a group of organisms which can reproduce independently and produce fertile young in all the essential matters of each other like morphology, physiology, embryology etc.

2. Why apple is called false fruit?        1

Ans:- This is because the apple is not formed from the ovary of the flower.

3. What is Kranz anatomy?         1

Ans:- It is a special pathway structure in the leaves of plants in which the C4 pathway CO2 fixation takes place.

4. Write the importance of herbaria.        2

Ans: - There is importance of herbaria in Shodhdwar.

5. Draw and label the prothallus of fern.           2

Ans:-

6. Differentiate between parasitic and epiphytic plants with examples.     2

Ans:- Parasitic plants collect their food from their shelter. They cannot make their own food. For example, Cascutta.

Epiphytic plants prepare their own food; They live only on other plants.

7. Write the functions of stomate.        2

Ans:- Stomata remove excess water from the plant body and they also help in the exchange of gases in the plant body.

8. Explain the specific role of cytokinin in plant growth a development.          2

Ans:- Cytokinins influence various traits of plant growth, development and physiology such as seed germination, apical dominance, flower and fruit development, leaf senescence and plant-pathogen-interactions, etc. Cytokinins are isoprenoid substituted adenine molecules.

Cytokinins play important regulatory roles during cell differentiation, cell proliferation and many other developmental processes in vivo (Mok and Mok, 2001). Endogenous cytokinin homeostasis is found to be spatially and temporally regulated due to the balance between synthesis and catabolism. There have been many studies that characterize and isolate enzymes that function in plant cytokinin biosynthesis. Cytokinins also play an important role in new regeneration.

9. Write the structure and functions of Golgi complex with diagram.        1+1+1=3

Ans: The structure of the Golgi system is made up of flaps of membranes also known as cisterns. These flaps are in a series of 5 or 8 flaps, and they function by using enzymes to move proteins.

The goggle apparatus serves to transport the macromolecules necessary for the cells to function properly.

10. Name different types of RNA. Mention their functions.          1+2=3

Ans:- (i) mRNA – Messenger RNA: Encodes the amino acid sequence of the polypeptide.

(ii) tRNA – Transfer RNA: Brings amino acids to the ribosome during translation.

(iii) rRNA – Ribosomal RNA: Along with ribosomal proteins, forms ribosomes, the organelles that translate mRNA.

(iv) snRNA - Small nuclear RNA: Combines with proteins to form complexes that are used in RNA processing in eukaryotes. (Not found in prokaryotes.)

Of the many types of RNA, the three best-known and most studied are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA), which are present in all organisms. These and other types of RNA mainly perform biochemical reactions similar to enzymes. However, some also have complex regulatory functions in their cells. Because of their involvement in many regulatory processes, their abundance and their diverse functions, RNAs play important roles in both normal cellular processes and diseases.

11. Explain the role of macronutrients found in plants.             3

Ans:- Plants are living organisms and they also need nutrients like ours to survive, grow, reproduce and develop. Macronutrients in plants are nutrients that provide energy to plants and are needed in large quantities to maintain their growth and development. These are the most important elements required for crops and examples include nitrogen (N), potassium (K), calcium (Ca), phosphorus (P), magnesium (Mg), sulphur (S), oxygen (O), carbon (C). Are included, and hydrogen (H). The most important of these are nitrogen, phosphorus and potassium, which directly affect plant growth and actually form the various parts of the plant. In addition, nitrogen is an important component of chlorophyll which plays an important role in photosynthesis (the food synthesis process).

Macronutrients and micronutrients in plants come under essential nutrients that support plants for all biochemical needs and those without:

A plant cannot complete its life cycle.

Other elements cannot replace the specific function of the plant.

Plants cannot get complete nutrition because every essential nutrient is directly involved in plant nutrition.

About half of all essential nutrients are considered macronutrients and the functions of macronutrients are very essential, for example, carbon is needed to make proteins, carbohydrates, nucleic acids and other compounds or major plant macromolecules.

12. Discuss the Blackman’s law of limiting factor with help of graphic representation.          3

Ans:- Blackman planned the law of limiting factors in 1905. in line with this law, once a method depends on many factors, its rate is proscribed by the speed of the slowest issue. Blackman's law of limiting issue determines the speed of chemical process.

Suppose a leaf is exposed to an explicit intensity level which will use five mg. CO2 per hour in chemical process. If just one mg. CO2 enters the leaf inside associate degree hour, limiting the speed of chemical process because of the CO2 issue. however, because the concentration of CO2 will increase from one to five mg./hr, the speed of chemical process additionally will increase on the AB line. during this case CO2 acts as a limiting issue.

13. “Flower is a modified shoot.” Justify the statement.         5

Ans:- The flower is considered to be a modified shoot in which the leaves turn into leaves (petals and petals) of the flower and the stem is condensed with the internodes in the form of pressed nodes and thalamus. In support of the above facts, the following facts may be cited.

(a) Homology of Flower Bud:

(i) The position of the flower bud is similar to that of the vegetative bud.

(ii) Sometimes flower buds are converted into vegetative buds called bulbils. For example, pineapple.

(b) Axial Nature of Thalamus:

(i) Sometimes the thalamus shows the development of nodes and internodes similar to a stem (androphore and gynophore).

(ii) Sometimes after the flower bears the leaves, the thalamus moves forward like a branch which has leaves. like roses

(c) Leafy Nature of Flowers Leaves:

(i) The flower parts in water lilies are leafy as they show a gradual transition from sepals to carpels through petals and stamens.

(ii) The leaves of flowers show the same veins as are seen in deciduous leaves.

(d) Phyllotaxy: The arrangement of flower parts on the thalamus is similar to that of the leaf parts on the stem.

Thus, we can conclude that thalamus is a suppressed stem and floral part is modified leaves.

14. What is Ascent of sap? Describe the transpiration pull and cohesion of water theory.        1+4=5

Ans:- The ascent of sap within the vascular tissue of plants is that the upward movement of water and minerals from the basis to the crown. vascular tissue could be a advanced tissue consisting of living and non-living cells. The conducting cells within the vascular tissue square measure typically non-living and embody varied teams of plants, tube members, and tracheids.

Due to transpiration, the mesophyll cells of leaves continuously lose water from the leaf surface for which they continuously absorb water from the xylem of the petiole. This creates tension in the xylem of the petiole which extends downward to the xylem of the roots and water is drawn upward as a continuous monolithic water column to reach the top of the plant.

The cohesion and adhesion of water molecules and the walls of xylem vessels form a continuous monolithic water column from root to leaves. Due to transpiration, the mesophyll cells draw water from the xylem vessels. Thus, a suction force is created which continuously pulls the water column upwards.

Or

Write the Tricarboxylic Acid Cycle of plant respiration.        5

Ans: The tricarboxylic acid cycle begins with the condensation of the acetyl group with oxaloacetic acid (OAA) and water to yield citric acid. The reaction is catalyzed by citrate synthetase. The citrate is then isomerized into isocitric. This is followed by two steps of decarboxylation, one-ketoglutaric acid and then succinyl CoA. Succinyl CoA is oxidized to OAA. During the conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesized.

There are three points in the cycle where NAD+ is reduced to NADH+H+, and a point where FAD+ is reduced to FADH2.

The summary equation for this stage of respiration is as follows

Glucose is thus broken down to liberate the K8 molecule of Co2 and NADH+H+, two of FADH2 being synthesized.

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