Best Sindh Class 9 Biology Solved Past Papers

2019-20, and 2021 Sindh and Karachi biology solved past papers class 9 Pdf Downlaod.

Biology Solved Past Papers Sindh Class 9

i) Horsetail is common name of:

A. Psilopsida
B. Lycopsida
C. Sphenopsida
D. Pteropsida
Answer:
C. Sphenopsida

ii) The secretions lacks enzymes:

A. Pancreatic juice
B. Saliva
C. Gastric juice
D. Bile
Answer:
D. Bile

iii) The deficiency of hemoglobin in a person is called:

A. Heart attack
B. Haemophilia
C. Anaemia
D. Angina
Answer:
C. Anaemia

iv) Urea is mainly synthesized in:

A. Liver
B. Lungs
C. Kidney
D. Nephron
Answer:
A. Liver

v) Muscles is human involved in locomotion are:

A. Smooth
B. Skeletal
C. Involuntary
D. Cardiac
Answer:
B. Skeletal

vi) Fruit is a ripened:

A. Ovule
B. Ovary
C. Flower
D. Carpel
Answer:
B. Ovary

vii) The inner most whorl of a flower is:

A. Androecium
B. Corolla
C. Gynoecium
D. Calyx
Answer:
C. Gynoecium

viii) The number of chromosomes in each cell of frog is:

A. 46
B. 26
C. 16
D. 14
Answer:
B. 26

ix) Green plants in ecosystem are:

A. Producers
B. Consumers
C. Decomposers
D. None of these
Answer:
A. Producers

x) Butterfly belongs to phylum:

A. Echinodermata
B. Annelida
C. Arthropoda
D. Mollusca
Answer:
C. Arthropoda

xi) The bird cannot fly:

A. Pigeon
B. Kiwi
C. Parrot
D. Sparrow
Answer:
B. Kiwi

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xii) Respiratory organs of insects are:

A. Malpighian tubules
B. Lungs
C. Trachea
D. Flame cell
Answer:
C. Trachea

xiii) He discovered the cell; basic unit of living organism:

A. William Harvey
B. Robert Hook
C. Galileo
D. Charles Darwin
Answer:
B. Robert Hook

xiv) Agaricus is commonly known as:

A. Bread mould
B. Yeast
C. Mushroom
D. All of these
Answer:
C. Mushroom

xv) This one of the following is not a consequence of deforestation:

A. Greenhouse effect
B. Soil erosion
C. Depletion of the ozone layer
D. Disturbed water cycle
Answer:
D. Disturbed water cycle

xvi) The group of marchantia is:

A. Anthocerotae
B. Hepaticae
C. Musci
D. Mosses
Answer:
B. Hepaticae

xvii) Glycogen is a molecule that belongs to:

A. Carbohydrates
B. Fats
C. Proteins
D. Vitamins
Answer:
A. Carbohydrates

xviii) The end products of respiration in plants are:

A. CO₂, H₂O, & energy
B. Starch and O₂
C. Sugar and O₂
D. H₂O and energy
Answer:
A. CO₂, H₂O, & energy

Write down four characteristics of Phylum Echinodermata. 

Characteristics of Phylum Echinodermata:

Echinoderms have rough, spiny skin. They are found only in the sea. They are pentamerous and have a unique water vascular system that pumps the external water throughout their bodies. This vascular system operates the soft, tube-shaped feet (tube feet) which enable the animal to glide over the rocks in the water. They do not have a head, eyes or even brain. Common examples are starfish, sand dollar, sea-cucumber, sea urchins, etc. Starfish have a plate-like central disc with five or more arms extended out from it. Sea Urchin has a ball-like body without arms. Its body is covered over externally by long spines.

Explain the flora of Pakistan on the following basis:

• Forests
• Food corps
• Fruit-bearing trees
• Ornamental trees
• Aquatic plants

i) Forests:

Forests and forestry are considered to be the backbone of our economy. They regulate the qualities of water in the rivers by preventing the free flow of soil in water by holding it with their roots. They prevent the formation of deserts, control waterlogging and maintain the number of salts in the soil and regulate the temperature of the atmosphere. They not only supply oxygen to the air but also provide food and shelter to animals (wildlife). They are an integral part of our ecosystem. Some of the economically important flowering and non-flowering plants of Pakistan are discussed below:

The high mountains in the northern and northwestern parts of Pakistan, due to sufficient snowfall, support thick forests. These forests consist of trees like blue pine, chir pine, chilgoza pine, deodar, fir, juniper, and olives, etc.

Forests of desert plants like Acacia are found in areas where there is less rainfall and scarcity of water. Trees of Sheesham, Mulberry, Willow, Poplar, Neem, etc. are found in irrigated lands like Changa Manga. These forests play a key role in providing us with wood for furniture, sports goods and fuel.

ii) Food crops:

In the plains, many crops are cultivated which fulfil our nutritional and other requirements. These crops include wheat, maize, rice, sugar, cane, sugar beet, pea, potato, tomato, onion, garlic, chilli, turnip, radish, carrot, cauliflower, many bowls of cereal, grains, and cotton, etc.

iii) Fruit-bearing trees:

Pakistan is also rich in fruit-bearing trees like mangoes, apples, apricots, peaches, oranges, bananas, walnuts, and almonds, etc.

iv) Ornamental trees:

Many plants are cultivated for ornamental purposes e.g. Chrysanthemum, roses, and jasmines, etc.

v) Aquatic trees:

A large number of plants like Typha, Hydrilla, and many types of algae are found in freshwater ponds, lakes, streams, and rivers. A variety of marine plants are found in oceans and coastal regions of our country.

Describe the structure of a neuron with the functions of its all parts. (Diagram is not required)

Structure of Neurons: 

The nervous system consists of special cells called neurons. They can generate and conduct a mild electric current whose transmission from one neuron to another is called nerve impulse.

Parts of the neuron:

Each neuron consists of a:

1. Cell body or soma
2. Cell dendrites
3. Axon

1. Cell soma:

Soma contains cytoplasm, organelles, and nucleus.

2. Dendrites:

Dendrites are much-branched thread-like projections for receiving impulses.

3. Axon:

On the contrary, the axon is usually un-branched, single, elongated, fibre specialized for conducting impulses to other neurons. At its terminal end, many branches are given out to form an endplate. Axons are usually covered by a myelin sheath for insulation which ensures uninterrupted flow of nerve impulse from one neuron to another. Many cell processes, axons and sometimes dendrites, combine to form a nerve. Nerve impulses pass along the nerve fibres in only one direction.

What are antibiotics? Describe their four types.

Antibiotics:

Antibiotics are chemicals that are widely used to kill pathogenic bacteria and thus to treat many infectious diseases caused by them. These chemicals are produced by certain living bacteria and moulds. However, a few antibiotics are man-made.

Four main types of antibiotics:

1. Penicillins:

These are produced by the fungus Penicillium. These attack a fairly narrow range of bacteria and are, therefore, called narrow-spectrum antibiotics.

2. Cephalosporins:

These are produced by the mould, Cephalosporium. They are useful against bacteria that have developed resistance to penicillin.

3. Tetracyclines:

They are produced by the Streptomyces bacteria, which act against a variety of bacteria i.e. they are broad-spectrum antibiotics.

4. Erythromycins:

They work against the same sort of bacteria as penicillin and are, therefore, useful against bacteria that have developed resistance to penicillin.

What do you mean by asexual reproduction? Describe any one method of asexual reproduction in plants. 

Asexual Reproduction:

Asexual reproduction is a type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only; it does not involve the fusion of gametes and seldom changes the number of chromosomes.

Asexual reproduction is the primary form of reproduction for single-celled organisms such as the archaebacteria, eubacteria, and protists. Many plants and fungi reproduce asexually as well.

Types of Asexual Reproduction in Plants:

Plants reproduce asexually by several methods. Some of these are:

• 1. Binary fission
• 2. Budding
• 3. Spore formation
• 4. Vegetative propagation

Vegetative propagation of flowering plants:

Vegetative reproduction in flowering plants (Angiosperms) is brought about by specialized vegetative organs which sooner or later become separated from the parent plants. These specialized organs are morphologically different in different cases but in nearly all cases they bear one or more buds that develop into new plants.

Naturally, vegetative propagation occurs in runners (grass and strawberry), stolon (mint), rhizome (ginger, banana), bulb (onion, garlic), stem tuber (potato), Bulbil (Myriophyllum), root tubers (sweet potato), phylloclades (opuntia), etc.

The vegetative propagation in most cases is due to the accumulation of large amounts of reserve food and the consequent vigorous growth of the vegetative parts.

Describe any two methods of dispersal of fruits and seeds.

Dispersal of fruits and seeds:

For better and healthier propagation of plants, the seeds and fruits must be dispersed in such a way that they do not fall directly underneath the mother plant because they soon exhaust the soil of its essential food constituents and compete for space, light, and water. To guard against their contingencies, seeds and fruits have developed many special devices for their widespread dispersal. It thus ensures that the risk of a species of the plant becoming extinct is reduced to a minimum.

The following are some ways by which the dispersalispersal of seeds and fruits takes place.

1. Dispersal of seeds and fruits by wind: 

Tiny and lighter seeds and fruits that are produced in abundance are generally dispersed through the wind. Due to their lightweight, the wind carries them to distant places as in grasses. Seeds and fruits of some plants are winged or hairy which helps them to be blown by air from place to place. Cotton, sumbal and calotropis (Akk) are examples of seeds that are dispersed by wind.

2. Dispersal of seeds and fruits by water: 

The seeds and fruits of the plants that grow in or along the banks of water bodies, are adapted to float and are easily dispersed by water. They contain spongy tissue that renders them lighter and allows them to float to distant places e.g. lotus, coconut, etc.

Describe different types of teeth in the human body with their function. Write dental formulas also.                                                            

Types of Teeth:

According to the shape and function, the following types of teeth are present in our oral cavity;

• Incisors
• Canines
• Premolars
• Molars

1. Incisors:

The flat chisel-shaped teeth present in front of the oral cavity are incisors. They are eight in number, four in upper and four in the lower jaws. They are used in cutting.

2. Canines:

Beside incisors lie canines on each side in both jaws. They are four in number and are pointed. They are used for tearing and pulling flesh. That’s why they are very long and prominent in carnivores such as the lion. Herbivore animals usually do not have canines.

3. Premolars: 

In both jaws, each canine is followed by two premolars. They are 8 in number and each with two distinct edges. They are involved in grinding the food.

4. Molars: 

Premolars of each side of both jaws are followed by three molars. They are 12 in number. They also grind food. The last molar is called a wisdom tooth.

Dental formula:

The arrangement of teeth can be represented by the following formula called dental formula.

                              Dental formula= I2/2, C 1/1, Pm2/2, M3/3

It represents each type of tooth in half of the upper jaw and half of the lower jaw.

Describe 4 types of bacteria according to shape.               

Types of bacteria according to shape:

Four types of bacteria according to shapes:

1. Cocci:

They are spherical and, according to cell arrangement, they are; solitary (single) (Monococcus), in pairs (Diplococci), in the chain (Streptococci), in the cluster (Staphylococci), etc. They are non-flagellated.

2. Bacilli:

They are rod-shaped. They may be found in pairs (Diplobacillus) or in chains (Streptobacillus) etc. They may be flagellated.

3. Spirilla:

They are spiral or corkscrew-shaped (spirillum).

4. Vibrio or comma:

They are slightly curved or comma (,) shaped e.g. Vibrio cholera. They may be flagellated.

Define: 

• Tracheophytes
• Plastids
• Osmosis
• Producers
• Photosynthesis

i) Tracheophytes:

Tracheophytes is commonly known as a vascular plant that has conducting or vascular tissues. Nearly all tracheophytes have well-developed roots, stems and leaves. They include the angiosperm, clubmosses, ferns, horsetails, and gymnosperms.

ii) Plastids:

Plastids are doubled membraned ‘sac-like’ organelles, generally involved in either the manufacture or storage of food. They include chloroplasts, chromoplasts, and leucoplasts.

iii) Osmosis:

Osmosis is the movement of water or other solvents through a plasma membrane from a region of low solute concentration to a region of high solute concentration.

iv) Producers:

Producers are organisms that make their food; they are also known as autotrophs. They get energy from chemicals or the sun, and with the help of water, convert that energy into usable energy in the form of sugar, or food.

v) Photosynthesis:

Photosynthesis is the process by which green plants and certain other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds.

Name 5 hormones of plants. Briefly explain any 2 of them.

Hormones of plants:

The important plant hormones are:

1. Auxins
2. Gibberellins
3. Cytokinin
4. Abscisic acid
5. Ethylene.

1. Auxins: 

Stimulate the growth of the shoot and root. Due to the effect of auxins, the shoots move towards light against gravity whereas the root grows away from the light and towards gravity. Auxins stimulate growth by promoting cell elongation rather than increasing the number of cells.

2. Gibberellins:

Stimulates rapid growth of the stem mainly by causing cell elongation. They stimulate cell division too. They are also involved in breaking the dormancy of seeds and buds.

Write down five points of the importance of Fungi.

Importance of Fungi:

1. Food: 

Several fungi in the form of mushrooms are a source of food dishes. Today they are grown as a crop in many places throughout the world. But one must bear in mind that not all mushrooms are edible. Some of them are poisonous and popularly called toadstool or death-stool. Yeasts, another kind of fungi, are utilized in the baking industry. Others are used in brewing, and cheese and organic acid-producing industries.

2. Medicines:

Fungi have opened a new field in medicine being the course of antibiotics like Penicillin, Chloromycetin, Neomycin, Terramycin, etc.

3. Soil fertility:

They maintain soil fertility by decomposing the dead organic matter.

4. Fermentation:

The property of fermentation is utilized for the manufacture of ethanol, organic acids, and alcoholic beverages. Saccharomyces cerevisiae (brewer’s yeast) synthesizes a range of vitamins of the B-group.

5. Food spoilage:

Fungi cause tremendous amounts of spoilage of food-stuffs by many of the saprophytic fungi.

Write 5 differences between Angiosperm and Gymnosperm plants.

Angiosperms	Gymnosperms
Angiosperms are those flowering tracheophytes that produce seeds within fruits.	Gymnosperms are seed-bearing vascular plants, in which the ovules or seeds are produced in cones.
The ovary in angiosperms develops into the fruit whereas the ovules become seeds enclosed within the fruit.	Ovules develop into naked seeds as fruit is absent due to the absence of ovaries.
Double fertilization is present.	Double fertilization is absent.
The flower is bisexual, contains male and female reproductive parts in the same flower.	Cones are unisexual. Two types of cones are produced i.e. male and female cones.

Discuss why viruses are considered as living organisms & which characteristics differentiated them from living organisms?

Living characteristics of viruses:

Viruses are considered living organisms because of the following characteristics:

• Viruses with their core of DNA or RNA surrounded by a protein co somewhat resemble the chromosomes of other living organisms.
• They can reproduce (Property of replication reproduction).
• Many kinds of viruses are known to undergo mutations.
• Viruses show genetic recombination.

Non-living characteristics of viruses:

The following characteristics distinguish viruses from living organisms:

• Non- cellular structure
• Undergo crystallization
• Completely inactive outside the host’s cell

State Lamarck’s theory of evolution giving an example of a Snake or Giraffe.

Lamarck’s theory of evolution: 

J.B. Lamarck (1744 – 1829), a French biologist, proposed that organisms modify their bodies through the use or disuse of organs and these modifications can be inherited by the parents of their offspring. According to him the continuous use of any organ would develop that organ while disuse would result in gradual weakening and its ultimate reduction and disappearance in the subsequent generations. Such characters were termed as acquired characters. This idea about evolution is known as Lamarck’s theory of evolution or Lamarckism.

Example of Giraffe:

To explain his hypothesis, Lamarck proposed the example of the long neck and fore-limbs of giraffes. He proposed that the ancestors of giraffes were small necks and grazes on grasses. Due to some unknown reasons, the grasses on the ground either destroyed or became unavailable to the ancestors of a giraffe so they had to stretch their necks to reach the leaves of trees which were higher off the ground. Thus as a result of continuous stretching of the neck for generations, the present giraffe with a longer neck and longer fore-limbs were evolved.

From the above example, it seems that the use or disuse of the organs can be inherited by the offspring. August Weismann (1807) opposed Lamarckism. He cut the tails of mice for several continual generations but every new generation of mice was born with fully developed tails. Weismann proposed that the changes due to the use or disuse of organs mainly affect the somatic (body) cells and not the gametes, therefore they could not be inherited.

                                                              “OR”

Example of Snake:

As far as the disuse of the organs is concerned, Lamarckism could be explained with the example of modern snakes. Like other reptiles, the ancestors of snakes had four limbs to move on land. However, to escape from their enemies, they had to hide under stones or in holes by creeping in narrow cracks in rocks. This kind of movement required muscles rather than limbs. Therefore, as a result of the disuse of limbs generation after generation, the snakes lost their limbs and their bodies became cylindrical and elongated.

From the above example, it seems that the use or disuse of the organs can be inherited by the offspring. August Weismann (1807) opposed Lamarckism. He cut the tails of mice for several continual generations but every new generation of mice was born with fully developed tails. Weismann proposed that the changes due to the use or disuse of organs mainly affect the somatic (body) cells and not the gametes, therefore they could not be inherited.

Define joints. Write two defects of the skeletal system.              

Joints: 

The junction of two or more bones in our skeleton is called a joint.

Defects of the skeletal system:

1. Dislocation of joints:

It refers to the displacement of the two bones in a joint usually as a consequence of injury. It is usually accompanied by tearing of joint ligament as well as damage to the capsule. Dislocation of joints is diagnosed by severe pain, swelling and abnormal appearance of the joint.

2. Osteoporosis: 

Osteoporosis is a disorder related to the ageing process. In this condition, the bones become porous or more spongy, thinner and weaker so that they become fragile and a slight injury may break the bone. Women suffer more than men. Although it can affect the whole skeleton, hip, wrist, and vertebrae tend to be worst affected.

Explain five factors affecting the rate of transpiration.        

Answer:

Factors affecting the rate of transpiration: 

The rate of transpiration is affected by the following environmental factors:

i. Light: 

It is one of the most important factors because it regulates the opening and the closing of stomata. The stomata remain wide open during daytime as a vapours resultmodificationscell wallanspiration takes place through them. But at night they are closed, hence transpiration is greatly checked.

ii. Temperature: 

The increase in temperature increases the rate of transpiration by increasing the rate of evaporation of water from the cell surface.

iii. Humidity:

Transpiration decreases with the increase in humidity (moisture of the air) and increases with the decrease in humidity. It means that transpiration can take place only when the atmosphere is partially saturated or dry. The difference in the water content of the plant and that of the atmosphere affects the rate of transpiration.

iv. Wind: 

The increase in wind velocity increases the rate of transpiration by removing the water vapors surrounding the plants.

v. Atmospheric Pressure: 

The low atmospheric pressure increases the rate of transpiration through a reduction in the density of the air.

What changes did Margulis and Schwartz suggest in Whittaker’s scheme? Explain their all suggested kingdoms.

Changes by Margulis and Schwartz in Whittaker’s scheme:

Although Whittaker’s Scheme received widespread approval, it had one major drawback. This relates to the protist kingdom, which contained all unicellular organisms, including those that formerly had been regarded, like the animal (Protozoan) and those that had been regarded as the plant (unicellular algae). Another problem was that it meant putting the algae into two separate kingdoms, the Protista, and the plant kingdom.

This led two other biologists, Margulis and Schwartz, to put forward modifications of Whittaker’s scheme (1989). According to this, there are five kingdoms of living organisms as listed below:

1. Kingdom Prokaryotae: 

It includes all the prokaryotes, e.g. bacteria and cyanobacteria, etc.

2. Kingdom Protoctista: 

It includes all the eukaryotic organisms, which are no longer classified as animals, plants or fungi. e.g. Euglena, Paramecium, Chlamydomonas, yeast etc.

3. Kingdom Fungi: 

It includes non-chlorophyllous, multicellular, eukaryotic organisms having cell-wall e.g. Agaricus (mushroom), etc.

4. Kingdom Plantae: 

It includes all the chlorophyllous multicellular eukaryotic living organisms, having cell-wall and embryonic development e.g. Apple, Sunflower, etc.

5. Kingdom Animalia:

It includes all the non-chlorophyllous multicellular eukaryotic organisms, having no cell wall, e.g. hydra, earthworm, man, etc.

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