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Plant Reproduction
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Plant Reproduction
Plant Reproduction
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1
Question
What is asexual reproduction and in which types of organisms does it commonly occur?
Answer
Asexual reproduction is the production of new individuals from a single parent. It commonly occurs in single-celled or unicellular organisms such as bacteria and protists, some simple multicellular animals like hydra and sea anemone, and some insects like aphids under suitable conditions.
2
Question
How do unicellular organisms such as bacteria reproduce asexually?
Answer
They reproduce by binary fission, where the genetic material inside the nucleus is copied and the nucleus divides followed by the cytoplasm, forming two new identical cells.
3
Question
Describe the process of binary fission in amoeba.
Answer
The amoeba’s nucleus divides into two, followed by the division of the cytoplasm, resulting in two smaller cells that then feed and grow.
4
Question
What is sexual reproduction and what are its basic requirements?
Answer
Sexual reproduction is a process that requires two parents to produce offspring. It involves the joining of sex cells called gametes; the male gamete joins with the female gamete through fertilization, forming a zygote that grows into a new organism.
5
Question
What is a zygote?
Answer
A zygote is the cell formed when a male gamete fertilizes a female gamete during sexual reproduction; it eventually grows into a new organism.
6
Question
What is budding as a method of asexual reproduction?
Answer
Budding is when the parent cell develops an outgrowth of cytoplasm called a bud. When the bud nearly grows as big as the parent, the nucleus of the parent is copied and divides into two, forming a new organism. This method can produce more than one bud at a time.
7
Question
Give an example of an organism that reproduces by budding.
Answer
Yeast cells and hydra reproduce by budding.
8
Question
What is vegetative reproduction in plants?
Answer
Vegetative reproduction is a form of asexual reproduction in flowering plants where new plants grow from parts of the parent plant such as roots, stems, or leaves, often involving storage organs that store food.
9
Question
What are examples of storage organs in vegetative reproduction?
Answer
Examples include corms, bulbs, and rhizomes.
10
Question
How do runners contribute to asexual reproduction in plants?
Answer
Runners are stems that grow horizontally away from the parent plant without involving a storage organ. The tips of runners form roots that grow into the soil and shoots that become new plants, as seen in strawberries and water grass.
11
Question
Explain how cuttings are used as a method of asexual reproduction.
Answer
Cuttings involve cutting part of a plant such as a stem from the parent plant and placing it in soil. The cutting then grows roots and shoots to form a new plant. Common examples include hibiscus, cassava, and sugar cane.
12
Question
What is tissue culture in plant reproduction?
Answer
Tissue culture is a cloning method where tissues from stem tips, root tips, or buds are taken and placed on agar in petri dishes to develop into plantlets, which are then transferred to pots to grow into whole new plants.
13
Question
Describe grafting as a method of plant propagation.
Answer
Grafting joins parts from two or more plants so they grow as a single plant. The upper part (scion) of one plant is joined to the root system (rootstock) of another plant.
14
Question
What is the role of the flower in sexual reproduction in plants?
Answer
The flower is the organ of sexual reproduction in plants.
15
Question
What are sepals and what is their function?
Answer
Sepals are the outermost part of the flower that protect the flower while it is developing as a bud.
16
Question
What are petals and where are they located in the flower?
Answer
Petals form inside the sepals and are brightly colored to attract pollinators.
17
Question
What is the stamen, and what role does it play in the flower?
Answer
The stamen is the male part of the flower responsible for producing male gametes (pollen).
18
Question
What is the carpel in a flower?
Answer
The carpel is the female part of the flower involved in sexual reproduction.
19
Question
What are the main structures of the stamen and their roles in plant reproduction?
Answer
The stamen consists of the filament and anther. The anther produces pollen grains which contain the male gametes.
20
Question
What are the components of the carpel in flowering plants and their functions?
Answer
The carpel consists of the stigma, style, and ovary. The stigma is a sticky structure that catches pollen grains; the style connects the stigma to the ovary; the ovary contains ovules, each with a female gamete.
21
Question
Define pollination in the context of plant sexual reproduction.
Answer
Pollination is the process by which pollen grains are transferred from the anther to the stigma.
22
Question
What is the difference between self-pollination and cross-pollination?
Answer
Self-pollination is the transfer of pollen to the stigma on the same flower or another flower on the same plant, while cross-pollination is the transfer of pollen from a flower on one plant to a stigma of a flower on another plant of the same species.
23
Question
What are some common pollinating agents that help in the process of pollination?
Answer
Pollinating agents include the wind, birds, and insects.
24
Question
Describe the process of fertilisation in flowering plants.
Answer
After pollen lands on the stigma, a pollen tube grows down the style into the ovary and ovule. The male gamete travels down this tube and fuses with the female gamete inside the ovule, producing a zygote that develops into a seed; the ovary develops into the fruit.
25
Question
What is the structure and function of a seed in plants?
Answer
A seed consists of an embryo, a food store, and a tough outer coat called the testa. The food store provides nourishment for the embryo, and the tough testa protects it. Seeds can stay dormant until conditions are suitable for germination.
26
Question
How does the ovary of a flower develop after fertilisation?
Answer
After fertilisation, the ovary develops into the fruit surrounding the seed.
27
Question
Why is the stigma described as a swollen sticky structure?
Answer
The stigma is sticky to effectively catch and hold pollen grains transferred during pollination.
28
Question
What happens to the seed tissue as the embryo fully develops?
Answer
As the embryo develops, the seed tissue loses water and becomes hard and dry, allowing the seed to remain dormant until conditions are right for germination.