Botany Solved Past Paper 2nd year 2011 Karachi Board


1. Choose the correct answer for each from the given options:

i) This is a type of orderly or programmed cell death:
* Necrosis
* Synapsis
* Mitosis

ii) The gametes of YVRR will be:
* RR
*all of these

iii) This is an example of sex-linked inheritance in human beings: •
* Colour blindness
* Sickle cell anaemia
* Huntington’s disease
* Cystic fibrosis

iv) The study o.f living things in relation to its environment is called:
* Community
* Ecosystem
* Ecology
* Succession

v) The decomposers of an ecosystem are:
* Parasitic bacteria
* Fungi
* Bacteria
Bacteria & Fungi

vi) These are the producers of a pond ecosystem:
* Bacteria
* Fungi
* Zooplankton

vii) The group of cells which is capable of division is called:
* Permanent
* Meristematic
* Mature
* Storage

viii) In this sub-stage of prophase 1 of meiosis, crosslnq over occurs:
* Diplotene
* Diakinesis
* Pachytene
* Zygotene

ix) This bacterium lives in the root nodules of leguminous plant:
* Rhizobium
* Clostridium
* Cyanobacterium
* Azotobactor

x) Sex determination in Drosophila was discovered by:
* T.H. Morgan
* Mendel
* Watson
* Darwin

xi) Estuary is the meeting place of:
* Lake and pond
* Sea and pond
* River and sea
* Two seas

xii) The salt concentration of sea water is generally:
* 3.5%
* 5%
* 4.6%
* 4%

xiii) In a cross, appearance of intermediate”character is known as:
* Co-dominance
* Incomplete dominance
* Epistasis
* None of these

xiv) Cell becomes flaccid in this solution:
* Isotonic
* Hypertonic
* Hypotonic
* None of these

xv) An example of groVith inhibitor is:
* Indol acetic acid
* Gibberellins
* Zeatin
* Abscisic acid

xvi) Secondary growth in stem is caused due to activity of:
* Cambium
* Xylem
* Phloem
* None of these


2.1) Define Autosome and Sex chromosomes.
Chromosomes, which are similar in males and females of same species are called autosomes and the chromosomes, which are different in them are called sex-chromosomes. Each individual possesses a pa1rof sex chromosomes, which are ~esignated as X and Y. The male possesses XY and female possesses XX chromosomes.

ii) How do plants cope with heat stress and cold stress? Explain.
See on Page # 461.

iii) Write a note on Sclerenchyma and its types.
See on Page # 493.

iv) Wbat is a meristem? Give its types.
See on Page # 464.

v) Differentiate between Racemose and Cymose inflorescence
Racemose Inflorescence: In racemose inflorescence, main axis called peduncle continues to grow. The flowers develop in acropetal succession and opening of flower is centripetal. Cymose Inflorescence: In cymose inflorenscene, main axis soon stops growing. The flowers develop in basipetal succession and opening of flower is centrifugal.

vi) Explain Interphase stage of cell cycle.
See on Page # 463

vii) Write a note on anyone:
(a) Photoperiodism
The plants responses to light period (Photoperiod) is called photoperiodism. One of the important photoperiodic response is flowering in flowering plants.
There are three types of plants according to photoperiod.
1- Short-day plants
2- Long-day plants
3- Day-neutral plants.

1- Short Day Plants: Those plants which require relatively short daylight period and long light period for flowering or day-Iengtt- below the critical value are called short-day plans.

Example: Xanthium (Cockelbur), Nicotiana (tobacco), Chrysanthemum, Queen rnary (Gul-e-daudi). Euphoribia.

2- Long-Day Plants: Those plants which require relatively long daylight and short night period for flowering or day-length above the critical value are called long-day plants.

Example: Spinaccae oleracea (Spinach) Beta vulgaris (sugar beet),
petunia, radish, lettuce.

3- Day-Neutral Plants: Those plants which are. independent of day length and can bloom under conditions of either longer or short days. These are also termed as dry-neutral plants.

Examples: Zea mays (corn) Lycopersicon esculentum (tomato), Halianthus annus (sunflower), Cucumis sativa (cucumber), cotton

(b) Types of seed germination
The breaking of dormany of seeds or awakening of slooping embryo is known is seed germination.
Types of Germination: There are three types of seed germination.
i) Epigeal Germination: This is a type of a germination in which cotyledons are carried above the soil due to rapid growth of hypocotyl,

Example: Castor oil Seed, Mung beans.

ii) Hypogeal Germination: It is a type of germination in which cotyleadons are remain under the soil due to rapid growth of epicotyl,

Example: Gram, Maize.

iii) Viviparous Germination: It is a type of germination in which seed germinate inside the fruit attached to parent plant. In this case radical elongates, swell in the lower part and gets stouter. Due to increase in weight of the seedling, it separates from the mother plant falls vertically in the soft mud and gets embedded and start growing.

Examples: Coconut, Palms, mangroves.

viii)Write a note on anyone:
(a) Light as a climatic factor
See on Page # 463.

(b) Topographic factor
The study of surface texture of soil is called topography. The altitude, slope and exposure are main topographic factors.

Altitude: Higher”altitudes are associated with low temperature and atmospheric pressure, higher rain, radiation and increased wind velocity, resulting different vegetation at different altitude levels.

Slope: The steepness of slopes affect the amount of radiation falling on them Steep slopes are also unable to retain much water due to faster drainage and hence it affects vegetation. If it is more steep then vegetation is xerophytic.

Exposure: ·At high altitudes exposure to sun and wind develops different types of vegetations as compared to altitude which are not exposed or less exposed to sun and wind. The areas which are more exposed have more animals a~ compared to areas with less exposure.

ix) Write a note on anyone:
(i) Tundra Biome
Ans: See on Page # 495.

(ii) Coniferous forest
Ans: See on Page # 496.

(iii) Desert Biome
A desert is defined as the region where rainfall is less than 25 cm per year, although desert can develop in certain hot regions where there may be more rainfall but an uneven distribution of animal cycle.
Occurance: Desert covers about 17% of land surface and are found commonly in, Africa, North Mexico, Westem USA. The desert of Pakistan and India are Thar, Thai, Cholistan.
Types of Deserts: On the basis of temperature there are two types of deserts.
1- Hot Desert: Sahara is a largest hot desert of the world.
2- Cold Desert: Gobi desert and Mangolia are the coldest desert.
High or low temperature .
Life is very difficult.
Low humidity .
Scanty of water.
Plants are Scattered and widely placed.
Desert Plants (Producers):
Deserts are not completely devoid of vegetation. Inspite of high temperature and dry seasons, plants are found there .
Some succulant shrubs and herbs are common:
Trees have deep root system .
Water is conserved by desert plants .
Common plants are Cactus, Euphorbia, Accacia, Capparis, Calotropis etc.
Desert Animals (Consumers):
Animals show adoptation for conserving water .
Many animals live in burrows, where humidity is higher and temperature is lower.
Many are nocturnal.
Urine is concentrated .
Excretion of water is small.
Sweet gland are locking.

x) Write a note on Genetic code or Chromosomal aberration.
Genetic code :See on Page # 498.
Chromosomal Aberration: See on Page # 459.

xi) Write a note on Down’s syndrome.
See on Page # 505.

xii) Write a short note on tissue culture.
See on Page # 484.

xiii) Define Incomplete dominance or Co-dominance.
Ans: See on Page # 494.

xiv) What do you mean by Necrosis and Apoptosis?
Necrosis: It occurs due to damage or injury in which the typical cell swells and bursts, releasing the intracellular contents which can damage neighbouring cells and cause inflammation.
Apoptosis: (Gr. means dropping off or falling off).
It is an internal programme of events and sequences of morphological changes by which cell commit to suicide. During this the dying cells shrink and condense ultimately split up. Finally, release small membrane bound apoptotic bodies, which are generally phagocytosed by other cells.

xv) Make a chart showing chemical composition of chro osome.
Chemically chromosomes are composed of (Dexoyribonucleic acid) DNA (30-40%) and proteins (50~65%). The most abunoant chromosomal proteins are histones, substantial amount of RNA (1-10%) is also present in it




3.i) Discuss Watson and Crick model of DNA and its replication.
See on Page # 465.. .
OR What is Ecological succession? Describe Hydrosere or Xerosere in detail.
See on Page # 486.

ii) Define Meiosis. Describe various stages of Prophase – I of Meiosis.
Ans: See on Page # 489.

iii) How mar.y types of movements are found in plants? Describe Paratonic movement in detail.
Ans: See on Page # 467

Posted on December 30, 2015 in 2nd Year 2011 Karachi Board Past Papers

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