REPRODUCTION IN PLANTS - Q&A
REVIEW QUESTIONS
Multiple Choice Questions :
1. Put a tick mark (✓) against the correct alternative in the following statements :
(a) Pollen is produced in the :
(i) Filament (ii) Style (iii) Pistil (iv) Anther
Answer: (iv) Anther
Explanation: The stamen is the male part of the flower, consisting of a filament and an anther. The anther contains pollen sacs which produce pollen grains.
(b) Reproductive whorls of a flower are :
(i) Stamens and carpels (ii) Sepals and petals (iii) Sepals and stamens (iv) Petals and carpels
Answer: (i) Stamens and carpels
Explanation: Sepals (calyx) and petals (corolla) are non-essential or accessory whorls. Stamens (male) and Carpels/Pistils (female) are directly involved in reproduction, hence they are the reproductive whorls.
(c) Grafting is a method of :
(i) Artificial vegetative propagation (ii) Sexual reproduction (iii) Artificial pollination (iv) Cross-pollination
Answer: (i) Artificial vegetative propagation
Explanation: Grafting is a technique used by humans where a shoot (scion) is fixed onto a root system (stock) to grow a new plant. Since it involves vegetative parts and human intervention, it is artificial vegetative propagation.
(d) Which one of the following is a false fruit ?
(i) Tomato (ii) Apple (iii) Potato (iv) Pea
Answer: (ii) Apple
Explanation: A true fruit develops from the ovary. In an apple, the main fleshy part we eat develops from the thalamus (base of the flower), not the ovary. Therefore, it is called a false fruit.
Short Answer Questions :
1. Write two ways in which pollination may occur in plants.
The two ways/modes in which pollination may occur are:
1. Self-pollination: Pollen is transferred from the anther to the stigma of the same flower or another flower on the same plant.
2. Cross-pollination: Pollen is transferred from the anther of a flower on one plant to the stigma of a flower on a different plant of the same species.
2. Name the three agents of pollination.
The three common agents of pollination are:
1. Insects (Entomophily)
2. Wind (Anemophily)
3. Water (Hydrophily)
3. Give two features of flowers which favour pollination by insects.
Two features of insect-pollinated flowers are:
1. They have large, brightly coloured petals to attract insects.
2. They produce scent and nectar as food for the visiting insects.
4. Name two characteristics of flowers in which pollination occur by wind.
Two characteristics of wind-pollinated flowers are:
1. They produce large quantities of light pollen grains that can be easily carried by the breeze.
2. They have long anthers protruding out of the flower and feathery stigmas to catch the floating pollen.
5. What is a "false fruit" ? Give one example.
A "false fruit" is a fruit in which parts other than the ovary (such as the thalamus or base of the flower) become fleshy and form the main part of the fruit.
Example: Apple (or Pear).
6. Name any three agencies for dispersal of seeds.
Three agencies for the dispersal of seeds are:
1. Wind
2. Water
3. Animals (including humans)
7. Fill in the blanks by selecting suitable words :
(unisexual, fertilisation, fruit, stamen, anther, bisexual, pollination, seed, ovary)
(a) A flower that bears both the male and the female parts is known as bisexual flower.
(b) A flower bearing only male or female parts is known as unisexual flower.
(c) Transfer of pollen grains from the anther to the stigma is known as pollination.
(d) Fusion of male cell with the female cell is called fertilisation.
(e) The ovule develops into a seed.
(f) The ovary of the flower develops into a fruit.
Long Answer Questions (Write the answers in your note-book) :
1. What is vegetative reproduction ?
Vegetative reproduction (or vegetative propagation) is a form of asexual reproduction in plants where new plants are produced from the vegetative parts of the parent plant, such as the root, stem, or leaf, rather than from seeds. Examples include growing potatoes from tubers (stems) or Bryophyllum from leaves.
2. Briefly explain why a gardener prefers to grow certain plants vegetatively ?
A gardener prefers vegetative propagation for the following reasons:
1. Speed: Reproduction takes place in a shorter time compared to growing from seeds.
2. Certainty: It is a surer method of propagation; the plants are less likely to fail than seeds.
3. Genetic Uniformity: The new plants are exact copies of the parent, so all the good characteristics (like flower color or fruit taste) are retained.
4. Seedless Plants: It allows for the propagation of plants that do not produce viable seeds (e.g., bananas, rose).
3. Why is it disadvantageous to grow plants vegetatively ?
It can be disadvantageous because:
1. Disease Susceptibility: Since all plants are genetically identical, if a disease affects one plant, it is likely to spread quickly and destroy the entire crop.
2. Overcrowding: Dispersal does not happen naturally. Daughter plants tend to grow right next to the mother plant, leading to competition for resources (water, minerals, sunlight) in a restricted area.
4. What is meant by pollination ? Explain the structure of germinating pollen grain with the help of a labelled diagram.
Pollination is the process of transfer of pollen grains from the anther of a flower to the stigma of a flower of the same species.
Structure of germinating pollen grain:
When a pollen grain falls on a suitable stigma, it absorbs moisture and germinates. A tube called the pollen tube grows out of the pollen grain. This tube grows down through the style towards the ovary. The pollen tube carries the male gametes (male cells) inside it. Eventually, this tube enters the ovule in the ovary to facilitate fertilization.
(Note: Students should draw a diagram showing a spherical pollen grain with a long tube extending downwards, containing male nuclei, as shown in Figure 2.12 of the textbook).
5. Imagine all the seeds produced by a plant happen to fall under the same plant and sprout into new plants. Mention any two problems that will be faced by the new plants.
If all seeds fall under the parent plant, the new plants will face the following problems due to overcrowding:
1. Competition for Resources: There will be a severe shortage of water, minerals, and nutrients in the soil as too many roots fight for limited supplies.
2. Lack of Sunlight: The new plants will be shaded by the parent plant and each other, preventing them from getting enough sunlight for photosynthesis, leading to weak growth or death.
6. What is a flower ? Write down the structure of a typical flower with the help of a labelled diagram.
A flower is the reproductive part of a plant. It contains the sexual organs required for producing seeds and fruits.
Structure of a typical flower:
A typical flower consists of four main whorls arranged on a swollen base called the thalamus:
1. Calyx (Sepals): The outermost whorl of green, leaf-like structures that protect the flower in the bud stage.
2. Corolla (Petals): The second whorl of usually bright, coloured structures to attract insects.
3. Androecium (Stamens): The male reproductive part. Each stamen has a filament and an anther (which holds pollen).
4. Gynoecium (Carpels/Pistil): The female reproductive part located in the center. It consists of the ovary (basal swollen part), style (tube), and stigma (tip).
(Note: Refer to Figure 2.9 in the textbook for the labelled diagram showing these parts).
7. Write short notes on the following :
(a) Micro propagation
Micro-propagation is a modern method of artificial propagation (tissue culture). It involves taking a small piece of tissue (explant) from a plant (like a bud or shoot tip) and growing it in a sterilized nutrient medium. The cells divide to form a mass called 'callus', which is treated with hormones to develop roots and shoots. This produces many tiny plantlets in a very short time, which are disease-free and identical to the parent.
(b) Bryophyllum
Bryophyllum is a plant that reproduces vegetatively through its leaves. The leaves have notches along the margins. Adventitious buds develop in these notches. When the leaf falls on moist soil, these buds grow into new young plants (seedlings) capable of independent existence.
(c) Vegetative reproduction
Vegetative reproduction is an asexual method where new plants arise from vegetative parts (roots, stems, leaves) without the formation of seeds. It is common in plants like potato (stem tuber), ginger (rhizome), and sweet potato (root). It ensures rapid growth and preserves the parent plant's characteristics.
(d) Grafting
Grafting is an artificial method of vegetative propagation. It involves joining parts of two different plants so they grow as one. A shoot (called the scion) from a desired variety is placed onto the root system (called the stock) of a hardy plant. They are tied together until their tissues combine. This is commonly used in roses, mangoes, and citrus fruits.
8. How artificial pollination is useful to plant breeders ? Discuss briefly.
Artificial pollination allows plant breeders to develop new varieties of plants with desired characteristics. By manually transferring pollen from a plant with specific good traits (like high yield) to the stigma of another plant with other good traits (like disease resistance), breeders can cross-breed them. This creates offspring (hybrids) that possess the best qualities of both parents, improving crop quality and yield.
9. With the help of suitable diagrams, describe :
(a) Binary fission in plants
Binary Fission: This occurs in lower plants like bacteria. The mature cell nucleus elongates and divides into two. A constriction appears in the cytoplasm/cell wall, dividing the cell into two equal halves. Each half becomes a new identical daughter cell.
(See Fig 2.1 in the text for the diagram showing the cell splitting).
(b) Budding in yeast cell
Budding: In yeast, a small bulb-like outgrowth called a 'bud' appears on the parent cell. The nucleus divides, and one part moves into the bud. The bud grows, eventually detaches from the parent, and becomes a new independent yeast cell. Sometimes, buds form chains before separating.
(See Fig 2.2 in the text for the diagram showing the bud formation).
Question 1What is the biological process by which living organisms produce individuals of their own kind?
Question 2Which type of reproduction involves flowers and seeds?
Question 3In binary fission, what does the term 'binary' mean?
Question 4Which organism reproduces through budding?
Question 5What is the name of the outgrowth produced by a parent cell during budding?
Question 6Which organism is known for reproducing by fragmentation?
Question 7In which type of fission does one cell divide into four daughter cells?
Question 8Where are spores typically found in mosses and ferns?
Question 9What are the vegetative parts of a plant used for propagation called?
Question 10Which of these is a modified stem used for vegetative reproduction?
Question 11What are the buds on a potato tuber commonly called?
Question 12In an onion bulb, where is the food stored?
Question 13Which plant produces adventitious buds in the notches of its leaf margins?
Question 14Which of the following plants reproduces through its roots?
Question 15What is a primary advantage of vegetative reproduction?
Question 16What is a major disadvantage of asexual reproduction in a farm setting?
Question 17Which artificial method involves bending a lower branch to touch the soil to grow roots?
Question 18In grafting, what is the term for the shoot fixed onto the rooted plant?
Question 19In grafting, what is the rooted plant that receives the new shoot called?
Question 20Which tissue layer must come into close contact for a successful graft?
Question 21What is the cell mass formed during tissue culture called?
Question 22What is the collective name for the sepals of a flower?
Question 23Which part of the flower is collectively called the corolla?
Question 24What is the male reproductive part of a flower?
Question 25Which part of the stamen contains the pollen grains?
Question 26What are the three parts of a carpel?
Question 27What do we call a flower that contains both male and female parts?
Question 28What is the process of transferring pollen from the anther to the stigma?
Question 29Which type of pollination occurs when pollen falls on the stigma of a different flower on the same plant?
Question 30Which of these is a characteristic of insect-pollinated flowers?
Question 31Why do wind-pollinated flowers produce a large quantity of pollen?
Question 32Which plant is a common example of water-pollination?
Question 33In Vallisneria, how are pollen grains transferred?
Question 34What is 'artificial pollination' primarily used for today?
Question 35What is formed when a male cell fuses with a female cell?
Question 36The ovule develops into which part after fertilization?
Question 37Which part of the flower develops into the fruit?
Question 38From a scientific perspective, what is a fruit?
Question 39Why is an apple considered a 'false fruit'?
Question 40Which of these is a 'dry fruit' (scientifically, meaning the ovary wall is dry)?
Question 41What is the main reason plants need seed dispersal?
Question 42How are tomato seeds often dispersed over long distances by humans?
Question 43What is the enlarged, flattened tip of the flower stalk called?
Question 44What function do sepals perform in the bud stage?
Question 45What are the rounded bodies found inside an ovary called before fertilization?
Question 46In the context of micro-propagation, what is an 'explant'?
Question 47Which of these is an agent of pollination?
Question 48What is the path taken by the male cells to reach the ovule?
Question 49What is the primary food for insects provided by flowers?
Question 50Which plant is often propagated by stem cuttings?
Statement 1Reproduction is necessary for the survival of an individual organism's life.
Statement 2Reproduction ensures the survival of a species.
Statement 3Lower plants like bacteria mainly reproduce by binary fission.
Statement 4In binary fission, the nucleus divides after the cell splits.
Statement 5Binary means 'two' and fission means 'splitting'.
Statement 6Multiple fission results in only two daughter cells.
Statement 7Chlorella and Chlamydomonas can undergo multiple fission.
Statement 8Budding is a common method of reproduction in yeast.
Statement 9In budding, the bud must remain attached to the parent to survive.
Statement 10Spirogyra consists of long, ribbon-like filaments.
Statement 11Fragmentation involves a filament breaking into parts called fragments.
Statement 12Mosses and ferns are ornamental plants that produce seeds.
Statement 13Spores in ferns are located on the upper surface of the leaves.
Statement 14Spores are light and can be carried by wind or insects.
Statement 15Vegetative reproduction is also called vegetative propagation.
Statement 16The vegetative parts of a plant include the flower and fruit.
Statement 17Roots, stems, and leaves are considered vegetative parts.
Statement 18Common lawn grass grows its stems horizontally parallel to the ground.
Statement 19New shoots in grass develop at the internodes.
Statement 20Ginger is a modified root.
Statement 21Ginger has nodes, internodes, and scaly leaves.
Statement 22Axillary buds in ginger grow into aerial shoots.
Statement 23The potato is a modified underground stem.
Statement 24The 'eyes' of a potato are actually dormant buds.
Statement 25Potatoes store starch to provide food for new shoots.
Statement 26An onion bulb has a long, slender stem.
Statement 27Food in an onion is stored in fleshy scaly leaves.
Statement 28The stem of an onion is a condensed disc.
Statement 29Bryophyllum produces buds in the notches of its leaf margins.
Statement 30Bryophyllum buds grow into tiny plants while still on the parent leaf.
Statement 31Sweet potato reproduces through modified fleshy roots.
Statement 32Carrot is a perennial plant.
Statement 33Carrot roots store food during the first year of growth.
Statement 34Vegetative reproduction takes a longer time than reproduction by seeds.
Statement 35Plants produced vegetatively are genetically identical to the parent.
Statement 36Identical plants are less likely to be affected by the same disease simultaneously.
Statement 37In nature, vegetative offspring often compete for resources because they stay near the parent.
Statement 38Cutting, layering, and grafting are natural methods of reproduction.
Statement 39In the cutting method, each stem piece must bear an axillary bud.
Statement 40Layering is used to propagate plants like Jasmine and Mint.
Statement 41In layering, roots develop after the branch is cut from the main plant.
Statement 42In grafting, the shoot fixed on another plant is called the stock.
Statement 43The rooted plant receiving a graft is called the stock.
Statement 44For a successful graft, the cambium layers must be in close contact.
Statement 45Wax is used in grafting to prevent dehydration and infection.
Statement 46Micro-propagation is another name for tissue culture.
Statement 47An explant is a small part of a plant used for tissue culture.
Statement 48A callus is a mass of undifferentiated cells.
Statement 49Plant hormones are added to the callus to help it differentiate into plantlets.
Statement 50Tissue culture can be used to multiply disease-free plant stock.
Question 1The process by which living organisms produce individuals of their own kind for survival is called ______.
Question 2Reproduction through flowers and seeds is known as ______ reproduction.
Question 3Lower plants like bacteria reproduce asexually by the method of ______ fission.
Question 4In binary fission, the parent cell splits into two identical cells called ______ cells.
Question 5When one cell divides into four daughter cells, as seen in Chlorella, it is called ______ fission.
Question 6Budding is a common asexual method found in ______.
Question 7In budding, the parent cell produces an outgrowth called a ______.
Question 8Organisms like ______ reproduce by breaking their ribbon-like filaments into fragments.
Question 9The method where a filament breaks into parts that grow into individuals is called ______.
Question 10Ornamental plants like mosses and ______ reproduce through spore formation.
Question 11Spores are usually found on the ______ of the leaves in ferns.
Question 12In vegetative reproduction, new plants are produced by parts called ______.
Question 13The three main vegetative parts of a plant are the leaf, root, and ______.
Question 14Common lawn grass and mint grow horizontally parallel to the ground using ______ stems.
Question 15Ginger is a modified ______ that has nodes and internodes.
Question 16The nodes of a ginger stem carry thin, dry, brown papery ______ leaves.
Question 17In ginger, new plants grow from ______ buds located at the nodes.
Question 18A potato is a modified underground stem called a ______.
Question 19The buds present on the surface of a potato are commonly called ______.
Question 20The onion bulb has a thick, short stem in the form of a condensed ______.
Question 21In an onion, food material is stored in fleshy overlapping ______ leaves.
Question 22The plant ______ produces adventitious buds in the notches of its leaf margins.
Question 23When Bryophyllum leaves fall on ______ soil, the buds grow into tiny plants.
Question 24Plants like ______ potato and asparagus reproduce using swollen fleshy roots.
Question 25A ______ is a taproot that acts as a biennial plant, growing vegetatively in the first year.
Question 26One advantage of vegetative reproduction is that it takes a ______ time than sexual reproduction.
Question 27A disadvantage of asexual reproduction is that identical plants are highly susceptible to the spread of ______.
Question 28The method of cutting, layering, and grafting are types of ______ vegetative propagation.
Question 29In the ______ method, a stem piece with an axillary bud is planted in moist soil.
Question 30The cutting method is commonly used for plants like sugarcane, rose, and ______.
Question 31In ______, a lower branch is bent to the ground and covered with soil to grow roots.
Question 32Layering is often used for the propagation of ______ and jasmine.
Question 33In grafting, the shoot of a desired variety fixed onto another plant is called the ______.
Question 34In grafting, the rooted plant that receives the new shoot is called the ______.
Question 35For a successful graft, the ______ layers of the stock and scion must be in close contact.
Question 36Grafting joints are covered with ______ to prevent dehydration and infection.
Question 37Propagation of plants by cell and tissue culture is also known as ______.
Question 38In tissue culture, the mass of dividing cells formed is called a ______.
Question 39The tiny plants produced during micro-propagation are called ______.
Question 40Tissue culture is very useful for propagating superior varieties of ______.
Question 41The ______ is the reproductive part of the plant.
Question 42A flower is attached to the shoot by a stalk called a ______.
Question 43The flattened tip of the flower stalk is called the ______.
Question 44The outermost whorl of a flower consisting of green leaf-like structures is the ______.
Question 45The sepals of a flower are collectively known as the ______.
Question 46The petals of a flower are collectively known as the ______.
Question 47The male reproductive part of a flower is the ______.
Question 48Each stamen consists of a hair-like filament and a sac-like ______.
Question 49Anthers produce a powdery material consisting of fine particles called ______.
Question 50The female reproductive part of a flower is the ______ or pistil.
Question 1
What process ensures the survival of a species?
Question 2
What are the two basic modes of reproduction in plants?
Question 3
What is another name for asexual reproduction in plants?
Question 4
Which type of reproduction involves flowers and seeds?
Question 5
How do bacteria primarily reproduce asexually?
Question 6
What does the word 'binary' mean?
Question 7
What does 'fission' mean?
Question 8
What are the two identical cells formed in binary fission called?
Question 9
In which organisms does one cell divide into four daughter cells?
Question 10
What is the division into more than two daughter cells called?
Question 11
Which organism is a common example of budding?
Question 12
What is the outgrowth produced by a parent cell in budding called?
Question 13
Which organism reproduces by fragmentation of filaments?
Question 14
What are the broken parts of a Spirogyra filament called?
Question 15
Which plants produce spores on the underside of their leaves?
Question 16
How are fern spores usually carried to different places?
Question 17
What are vegetative parts used for reproduction called?
Question 18
What are the three main vegetative parts of a plant?
Question 19
How does common grass grow horizontally?
Question 20
Where do new roots and shoots develop on a creeping stem?
Question 21
Is ginger a modified root or stem?
Question 22
What kind of leaves are found on ginger?
Question 23
Which buds grow into aerial shoots in ginger?
Question 24
Is a potato a modified root or stem?
Question 25
What are the buds on a potato tuber called?
Question 26
Which underground stem is a condensed disc?
Question 27
What stores food in an onion bulb?
Question 28
Which plant produces buds in the notches of its leaf margins?
Question 29
What type of roots does a sweet potato have?
Question 30
What kind of plant is a carrot based on its life cycle?
Question 31
Where are buds meant for propagation found in a carrot?
Question 32
Which method of reproduction takes shorter time?
Question 33
What is the primary risk of identical plants in a farm?
Question 34
Name one artificial method of vegetative propagation.
Question 35
Which method involves bending a branch to touch the soil?
Question 36
What is the plant receiving the graft called?
Question 37
What is the shoot fixed onto the stock called?
Question 38
Which layer must touch for a successful graft?
Question 39
What is used to protect a graft joint from infection?
Question 40
What is another name for micro-propagation?
Question 41
What is the cell mass formed in tissue culture called?
Question 42
What are tiny plants produced in tissue culture called?
Question 43
Name an ornamental plant grown by tissue culture.
Question 44
What is the reproductive part of a flowering plant?
Question 45
What is the stalk of a flower called?
Question 46
What is the flattened tip of the flower stalk called?
Question 47
What is the collective name for sepals?
Question 48
What is the collective name for petals?
Question 49
Which flower part is usually bright and attractive?
Question 50
What is the male part of the flower called?
Question 1
What is vegetative reproduction? Explain with two examples.
1. Ginger: It is a modified stem with nodes and internodes. Axillary buds at the nodes grow into new aerial shoots.
2. Potato: It is an underground modified stem (tuber) bearing buds called 'eyes'. Each eye can grow into a new plant when placed in moist soil.
Question 2
Describe the process of binary fission in bacteria with the help of steps.
1. Nucleus Elongation: The nucleus of a mature cell begins to elongate.
2. Nuclear Division: The nucleus divides into two daughter nuclei.
3. Constriction: A transverse constriction appears in the middle of the cell.
4. Cell Splitting: A wall is formed through the middle, splitting the parent cell into two identical daughter cells.
Question 3
List four advantages of vegetative reproduction that make it preferable for farmers.
1. Speed: Reproduction by vegetative parts takes place in a significantly shorter time compared to growing from seeds.
2. Rapid Spread: New plants produced this way can spread very fast across a small area.
3. Reliability: it is a surer method of propagation as it does not depend on external factors like pollination or seed germination success.
4. Genetic Consistency: All the desirable characters of the mother plant are exactly retained by the daughter plants.
Question 4
What is Grafting? Explain the roles of 'stock' and 'scion' in this process.
1. Scion: This is the small shoot or bud of a desired variety of plant that is fixed onto another.
2. Stock: This is the rooted plant receiving the scion.
For a successful graft, the cambium layers of the stock and scion must come into close contact. The joint is bound with tape and covered with wax to prevent dehydration and infection.
Question 5
Describe the structure and function of the four whorls of a typical flower.
1. Calyx (Sepals): The outermost whorl of green leaf-like structures that protect the inner parts of the flower in the bud stage.
2. Corolla (Petals): The second whorl, usually brightly colored to attract insects for pollination.
3. Androecium (Stamens): The male reproductive whorl consisting of anthers (which produce pollen) and filaments.
4. Gynoecium (Carpels/Pistils): The innermost female reproductive whorl consisting of the stigma, style, and ovary (containing ovules).
Question 6
What is pollination? Distinguish between self-pollination and cross-pollination.
1. Self-pollination: This occurs when pollen grains fall on the stigma of the same flower or another flower on the same plant.
2. Cross-pollination: This occurs when pollen grains from the anther of a flower on one plant are transferred to the stigma of a flower on a different plant of the same species.
Question 7
Explain the process of fertilization in plants from the moment pollen lands on the stigma.
1. Germination: The pollen grain absorbs moisture from the stigma and grows a pollen tube.
2. Growth: The pollen tube lengthens through the style and enters the ovary.
3. Entry: The tube enters the ovule and releases male cells.
4. Fusion: One male cell fuses with the female cell (egg) inside the ovule to produce a zygote.
5. Development: The zygote develops into an embryo, the ovule becomes a seed, and the ovary matures into a fruit.
Question 8
Why is seed dispersal necessary for the survival of plants? List the agents of dispersal.
The agents of dispersal are:
1. Wind (for light, dry seeds).
2. Water (for aquatic plants like Vallisneria).
3. Animals and Humans (through consumption of fleshy fruits or seeds sticking to bodies).
Question 9
What is 'Micro-propagation' (Tissue Culture)? Briefly outline the steps involved.
1. Selection: A small part of the plant (like a bud or shoot apex) is taken as an explant.
2. Sterilization: Explants are sterilized to prevent microbial growth.
3. Culturing: Explants are placed in a nutrient medium where cells divide to form a mass called a callus.
4. Differentiation: Growth regulators (hormones) are added to stimulate the callus to form tiny plantlets.
5. Transfer: After 4-6 weeks, plantlets are moved to soil.
Question 10
Identify and explain the special features of insect-pollinated flowers.
1. Large, Colored Petals: To be visually conspicuous to insects.
2. Scent: To help insects locate flowers by smell.
3. Nectar: Provided as food to encourage insect visits.
4. Sticky Pollen: So that grains easily adhere to the wings, legs, or mouthparts of the visiting insect.
Question 11
Differentiate between a 'true fruit' and a 'false fruit' with examples.
2. False Fruit: A fruit where the main fleshy part develops from parts other than the ovary, usually the thalamus or base of the flower. Examples include Apple, Strawberry, and Pear.
Question 12
How does Bryophyllum reproduce vegetatively? Explain the mechanism.
Question 13
Discuss the disadvantages of vegetative reproduction.
1. Lack of Genetic Variation: Since offspring are identical clones, they have no new traits to adapt to changing environments.
2. Rapid Disease Spread: If a disease affects one plant, all identical plants in the area are likely to be affected simultaneously.
3. Competition: Because dispersal does not happen naturally, daughter plants remain near the parent, leading to intense competition for resources.
Question 14
Describe the process of budding in yeast with a diagrammatic description.
1. The nucleus of the parent cell divides into two.
2. One daughter nucleus moves into the growing bud.
3. The bud grows until it is nearly the size of the parent.
4. Eventually, the bud develops a wall and detaches to lead an independent life as a new yeast cell.
Question 15
Explain the characteristics of wind-pollinated flowers.
1. Appearance: They are usually small and dull-colored (not needing to attract insects).
2. Pollen Quantity: They produce a very large quantity of pollen because much of it is lost in the air.
3. Pollen Type: Pollen grains are dry, light, and smooth to travel easily.
4. Anthers: Long anthers that protrude out of the flower to allow wind to blow the pollen off easily.
Question 16
What is 'Multiple Fission'? Give examples of organisms that exhibit this.
Question 17
Explain why an onion is considered a modified stem for storage and reproduction.
1. It has a thick, short, disc-like stem at the base.
2. This disc bears terminal and axillary buds.
3. It features fleshy, overlapping scaly leaves that store food material.
4. Under favorable conditions, the axillary buds grow into new green aerial shoots to form new plants.
Question 18
How do mosses and ferns reproduce? Mention the role of spores.
Question 19
Describe the method of 'Layering' in plants like Jasmine.
1. A portion of the branch is bent down so it touches the soil.
2. A ring of bark is removed from that section, and it is covered with moist soil.
3. A heavy object (like a brick) is used to keep the branch in place.
4. Once roots develop from the buried section, the branch is cut from the parent plant to grow independently.
Question 20
Define 'Fertilization' and list the post-fertilization changes in a flower.
Post-fertilization changes include:
1. The zygote develops into an embryo.
2. The ovule develops into a seed.
3. The ovary develops into a fruit.
4. The petals, stamens, style, and stigma usually wither and fall off.
5. The sepals may fall off or remain attached to the fruit.
Question 21
How does pollination occur in the aquatic plant Vallisneria?
1. The male flowers are submerged initially but detach when mature and float to the surface.
2. The female flowers have long stalks that bring them to the surface of the water.
3. When the floating male flowers drift and come into contact with the female flowers, pollen is transferred to the stigma.
Question 22
What are 'Dormant Buds' in potatoes, and how are they used in agriculture?
Question 23
Briefly explain the benefits of Tissue Culture for superior plant varieties.
1. Rapid Propagation: Large numbers of identical plants can be produced quickly.
2. Dormant Seeds: It allows for the culturing of embryos from plants where seeds are dormant or difficult to germinate.
3. Disease-Free Stock: It can be used to derive and multiply disease-free plants by using sterilized tissues.
4. Interspecific Hybrids: It can be applied to maintain rare or hybrid varieties that do not produce viable seeds.
Question 24
Compare the characteristics of pollen grains in wind-pollinated vs. insect-pollinated flowers.
2. Insect-pollinated: Pollen is produced in smaller quantities; grains are usually sticky or have spiny surfaces to easily attach to the hairs or appendages of an insect.
Question 25
What is the difference between bisexual and unisexual flowers?
2. Unisexual Flowers: Contain only one type of reproductive part. If they have only stamens, they are 'staminate'; if they have only carpels, they are 'pistillate'. Examples include papaya and corn.
Question 26
Describe the vegetative propagation in 'Sweet Potato'.
Question 27
Explain the role of the 'Thalamus' in a flower.
Question 28
How do humans and animals contribute to seed dispersal?
2. Attachment: Some seeds have hooks or sticky surfaces that attach to the fur of animals or clothing of humans, getting dropped off at distant locations.
Question 29
Describe the internal structure of a stamen.
1. Filament: A long, narrow, hair-like stalk that supports the anther.
2. Anther: A broad, sac-like, usually bilobed structure at the tip of the filament. Inside the anther, pollen grains are produced in specialized sacs.
Question 30
What is 'Artificial Pollination', and why do plant breeders use it?
1. Develop new varieties with desired traits (like disease resistance or higher yield).
2. Ensure cross-pollination between specific parent plants while preventing unwanted natural pollination by covering flowers with bags.