India 2016 — inbo2016-Q.pdf

Fonte: gare di altri paesi/India/biologia/inbo2016-Q.pdf · Apri PDF · apri PDF p.2 Cluster: Fisica Moderna Soluzioni (stessa cartella): · · · · · · · · · · ·

Problema 1

1. (1 point) There are several types of enzyme catalyzed reactions. In one type of enzyme catalyzed reaction, in addition to the catalytic site to which the substrate (X) binds, the enzyme also has a site to which some other substance (Y) can bind. When Y binds to such an enzyme, the enzyme can still bind to the substrate but cannot convert it to the product. Which of the following will occur in such a case? i. The affinity of the enzyme for the substrate will reduce. ii. Vmax of the reaction will decrease. iii. Y will alter the conformation of X. iv. The conformation of the catalytic site will be altered by binding of Y. v. The effect of Y can be overcome by increasing the concentration of X.

a. Only i, iii and v b. Only ii, iv and v c. Only i, ii and v d. Only ii and iv

Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.2

Problema 2

2. (1 point) In an experiment, E. coli cells growing at $37^{\circ }C$ were shifted to $20^{\circ }C$ and grown for a few generations. Which of the following changes in the membrane would help the E. coli cells adapt to the new environment? a. Increase in the unsaturated fatty acid content. b. Increase in the number of integral membrane proteins. c. Increase in the phospholipid content.

d. Increase in the length of the hydrophobic tail.

Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.2

Problema 3

3. (1 point) The shaker (sh) gene in Drosophila, when mutated, shows a typical behavior of continuous leg shaking. When the action potential of axons of such a shaker mutant of Drosophila was studied, it showed the following graph. 2

The graph indicates that the defect lies in the: a. functioning of activation gate of voltage-gated Na+ channel. b. functioning of inactivation gate of voltage-gated Na+ channel. c. functioning of voltage-gated K+ channel. d. strength of the electrical stimulus.

Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.2

Problema 4

4. (1 point) The nuclear membrane disappears during cell division. After completion of cell division, it re-appears during the interphase. Which of the following contributes towards formation of the nuclear membrane? a. Spindle fibre proteins b. Cytoskeletal elements c. Endoplasmic reticulum d. Golgi bodies

Topic: Nuclear & Particle Physics Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.3

Problema 5

5. (1 point) Eosin is an acidic stain that is widely used for staining cytoplasm of eukaryotic cells. Which of the following is responsible for this specificity? a. Ability of eosin to bind with water molecules in cytoplasm. b. Ability of eosin to bind with amino acids in cytoplasm. c. Eosin can cross the plasma membrane but cannot cross the nuclear membrane and hence accumulates in cytoplasm. d. Ability of eosin to bind with carbohydrate moieties in the cytoplasm.

Topic: Nuclear & Particle Physics Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.3

Problema 6

6. (1 point) In an experiment of mitotically dividing animal cells, nuclei of cells in G1 and G2 phases were removed. In the subsequent step, the G2 phase nuclei were introduced in enucleated cells of G1 phase. If these cells are cultured, what will be the consequence? a. Cells will abort cell cycle and enter G0 phase. b. Cells will shift directly from G1 to G2 phase. -60 +50 Membrane potential 0

• 40 4 8 12 16 mV Time (ms) 3 c. Cells will continue to stay in G1 phase. d. Cells will proceed from G1 to S phase.

Topic: Nuclear & Particle Physics Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.3

Problema 7

7. (1 point) Propidium iodide (PI) is a dye that can intercalate and stain cellular genome upon cell fixation. The amount of DNA indicated by the fluorescence intensity of PI in a population of cells which are in different stages of the cell cycle is depicted in the following graph. P, Q and R respectively indicate:

a. (G2), (S & G1) and (M). b. (G1), (G2&M) and (S). c. (G1), (G2) and (S&M). d. (S & G2), (G1) and (M).

PLANT SCIENCES (3 points)

Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.4

Problema 8

8. (1 point) The process of photosynthesis needs carbon dioxide to diffuse from the atmosphere into the leaf and into the carboxylation site of RUBISCO. This happens through a series of steps. Each step in this diffusion pathway imposes resistance to CO2 diffusion. This is depicted in the diagram. Various resistances are listed below.

i. Boundary layer resistance ii. Stomatal resistance iii. Liquid phase resistance iv. Intercellular air space resistance

R Q Cell number 0 4000 5000 10000 Fluorescence intensity P P Q R S 4 Which of the following shows the correct combination? a. P – i; Q – iii; R – ii; S – iv b. P – i; Q – ii; R – iii; S – iv c. P – iii; Q – iv; R – ii; S – i d. P – iv; Q – iii; R – ii; S – i

Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.4

Problema 9

9. (1 point) In Angiosperms, double fertilization provides the stimulus to the formation of seeds. Growth (measured as change in volume) of ovule, embryo and endosperm in Pisum is plotted in the graph.

I, II and III respectively represent: a. endosperm, ovule and embryo. b. ovule, endosperm and embryo. c. embryo, ovule and endosperm. d. endosperm, embryo and ovule.

Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.5

Problema 10

10. (1 point) The diploid chromosome number in the leaf cell of Pisum is 14. The diagram given below depicts the ovule structure immediately after fertilization. (Note: PEN refers to primary endosperm nucleus)

Structures 1 – 4 and the number of chromosomes present in them respectively are: Volume Development stages after double fertilization III I II 1 2 3 4 5

a. nucellus:7; integument:14; PEN:21; egg cell:7. b. nucellus:14; integument:14; PEN:21; zygote:14. c. embryo sac:7; integument:14; PEN:14; zygote:14. d. nucellus:14; integument:7; PEN:14; zygote:14.

ANIMAL SCIENCES (12 points)

Topic: Nuclear & Particle Physics Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.5

Problema 11

11. (1 point) The table shows body weight and food intake of a few selected animal species.

Based in the data provided, analyze the following statements.

Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.6

Problema 12

1. Smaller the animal, higher is the metabolic rate.

Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.6

Problema 13

larger intake of food

2. Larger the animal, greater is the energy requirement per unit body weight leading to larger intake of food.

Topic: Conservation of Energy Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.6

Problema 14

birds

3. Mammals consume larger proportion of their own weight as food daily compared to birds.

Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.6

Problema 15

4. Demand for food per unit of body mass increases as the metabolic rate increases.

The correct statements are: a. 1 and 2 b. 1 and 4 c. 2 and 3 d. 3 and 4

12. (1 point) The flat body plan of platyhelminthes helps them to: a. attain effective locomotion in any direction. b. minimize the loss of body fluid and maximize surface area. c. facilitate successful reproduction. d. maximize exposure of animal‘s cells/ tissues to the surrounding medium. Animal species Average body weight Average food intake/day Black Bear Euarctus americanus 135 kg 3.9 kg Common Shrew Sorese cinereus 5 gm 13 gm Pigeon Columba liva 300 gm 100 gm Horse Equus caballus 500 kg 12 kg 6

13. (1 point) In which of the following animals is the ̳heart‘ located dorsally? a. Flightless birds b. Lungfish c. Snakes d. Crabs

14. (1 point) Metamerism is a salient feature found in Annelids, dividing the body into a series of similar segments, each containing repeated arrangements of many of the internal organ systems. One of the following systems which is not metameric is the: a. integumentary system. b. nervous system. c. digestive system. d. excretory system.

15. (1 point) Which one of the following characteristics found in birds contributes LEAST towards the adaptation for flight? a. Keratinized beak b. Hind limbs c. Endothermy d. High metabolic rate

16. (1 point) The slow rate of oxygen diffusion in water limits the efficiency of oxygen distribution from gas exchange surface to sites of cellular respiration. This is true for: a. only aquatic animals. b. only air-breathing animals. c. only those animals in which no circulatory system has developed. d. all animals.

17. (1 point) Fish utilize oxygen dissolved in water. When the temperature of water rises, it can pose physiological stress to the fish as solubility of oxygen in water decreases. Which of the following graphs correctly depicts the oxygen consumption rates of resting fish and active fish under these conditions? Note: Oxygen consumption by active fish is indicated by solid line and by resting fish is indicated by dashed line. 7

18. (1 point) Environmental variables that limit respiratory gas exchange in animals can be explained by Fick‘s Law:

Where, Q= rate of diffusion. It is affected by i. D = diffusion coefficient (depends on the type of diffusing substance, medium and temperature) ii. A= cross sectional area iii. P1and P2 = partial pressures across two locations iv. L = path length

In fish, countercurrent exchange of gases across the gill lamellae results in very efficient gas exchange. Which of the following factors has the maximum influence on it? a. D b. A c. P1-P2 d. L

19. (1 point) Birds can sustain high levels of activity much longer than mammals even at high altitudes. Which of the following features found in birds helps in this? a. More efficient expansion and contraction of air sacs as compared to mammals. 100C 400C Oxygen consumption Arbitrary units c. Water temperature Oxygen consumption Arbitrary units 100C 400C Water temperature d. Oxygen consumption Arbitrary units 100C 400C a. Water Temperature Oxygen consumption Arbitrary units Water Temperature b. 100C 400C 8 b. Size of lungs larger than that of a mammal of comparable size. c. Air sacs allowing unidirectional air flow with minimum dead space. d. Circulatory system with more number of erythrocytes per unit volume of blood as compared to mammals.

20. (1 point) Oxygen saturation curves of haemoglobin for four different species at various partial pressures of oxygen are depicted in the graph.

P, Q, R and S respectively indicate:

a. mouse, cat, sheep and elephant. b. elephant, dog, cat and earthworm. c. crow, horse, dog and cat. d. crab, elephant, human and shrew.

21. (1 point) Which of the following is the correct depiction of circulatory pattern of water in poriferans?

22. (1 point) The volume of blood pumped by heart per minute is referred to as cardiac output. In an adult human, it is approximately 5 L. But, the amount of blood received by various organs of the body varies. Which of the following depicts correct hierarchy in terms of the amount of blood received by four key organs of human body viz. brain, skeletal muscles, kidney and skin? a. Skin < brain < skeletal muscles < kidney b. Skin < kidney < skeletal muscles < brain c. Kidney < skeletal muscle < skin < brain d. Skin < brain < kidney < skeletal muscles R % saturation of haemoglobin 5 10 15 20 Partial pressure of oxygen (mm Hg) S Q P a. b. c. d. 9 GENETICS & EVOLUTION (1 point)

23. (1 point) The rate of evolution varies in different lineages. For example: It is higher in rat lineage than in human lineage. Which of the following statements is correct? a. Rate of evolution would be the same for the coding and non-coding regions for a given species. b. Errors during DNA replication of somatic cells are the major source of mutations that leads to evolution. c. Rats have shorter generation time as compared to humans. Thus, more rounds of germ cell divisions would lead to more DNA replication errors. This can hasten rate of evolution. d. Humans show lower rate of metabolism than rats. This would lead to fewer errors during DNA replication thereby reducing the rate of evolution.

ECOLOGY (3 points)

24. (1 point) A common method used to compare the patterns of species richness and abundance between communities involves plotting the relative abundance of each species against rank (where rank is defined by the order of species from the most to the least abundant). The most abundant species is plotted first along the x-axis, with the corresponding value on the y-axis being the value of relative abundance. The following diagram depicts the rank-abundance curve for two forest communities 1 and 2.

A few statements regarding the forest communities are made below.

i. Community 1 has a higher number of species. 10 ii. Community 2 shows a higher degree of evenness in terms of abundance. iii. The most dominant member of community 1 has the highest relative abundance among all the species depicted in the graph. Based on the graph, the true statement/s is/are: a. i , ii and iii b. iii only c. i and iii only d. i only

25. (1 point) An experiment to understand the relationship between a herbivorous crab Mithrax forceps and the coral Oculina arbuscula was undertaken in a shallow water coastal ecosystem. Observation on predation of crab, growth of algae, growth and mortality of corals were made. The following graphs indicate the results obtained during the experiment. 11 A few statements based on the results obtained are made. i. The presence of crabs has a negative influence on algal growth and positive influence on coral growth. ii. Presence of M. forceps is obligatory for the survival of O.arbuscula. iii. The coral species plays an important role in preventing predation of M. forceps. iv. The algae outcompete O.arbuscula in the absence of M. Forceps. Which of these statements are true? a. i, ii and iii only b. i and iv only c. i, iii and iv only d. iii and iv only

26. (1 point) Two ecological pyramids are drawn below. If ̳I‘ represents aquatic and ̳II‘ represents terrestrial ecosystem, which of the following statements are true?

i. Pyramid ̳I‘ is based on biomass. ii. Pyramid ̳II‘ is based on numbers. iii. The unshaded box in pyramid ̳I‘ represents zooplankton and in pyramid ̳II‘ it represents insects. iv. Neither ̳I‘ nor ̳II‘ can be based on energy.

a. ii and iii only b. i and iii only c. i, ii and iv only d. i, ii, iii and iv

BIOSYSTEMATICS (3 points)

27. (1 point) Study the cladograms below that depict evolutionary history of species M, N, O, and P.

I II 12

Topic: Conservation of Energy, Thermodynamics, Special Relativity Metodi: Physical Modeling Competenze: Physical Reasoning Fonte: Testo (PDF) — p.6