iGCSE Biology (0610)-16.3 Sexual reproduction in plants – iGCSE Style Questions Paper 1

Question

Which species can breed with Prunella vulgaris to produce fertile offspring?

▶️Answer/Explanation

D

Prunella vulgaris, commonly known as self-heal or heal-all, is a herbaceous flowering plant in the in the mint family (Lamiaceae family). While it primarily reproduces through seeds, it is not known to hybridize naturally with other species to produce fertile offspring. Therefore, neither Prunella modularis (commonly known as the dunnock) nor Vespula vulgaris (common wasp) can breed with Prunella vulgaris to produce fertile offspring, as they are from entirely different biological kingdoms (animals and plants). Hybrids between different plant species are relatively rare and often result in sterile or partially sterile offspring due to genetic incompatibilities.

Question

What must always be available to allow seeds to germinate?
       A  carbon dioxide
       B  light
       C  mineral salts
       D  water

▶️Answer/Explanation

D

Water is the most critical factor required for seeds to germinate. It triggers the metabolic processes necessary for the seed to start growing and developing into a new plant. While light, carbon dioxide, and mineral salts are also important for plant growth, they may not be necessary at the initial stages of germination.

Question

The diagram shows a section of an insect-pollinated flower.
Which structure is the anther?

▶️Answer/Explanation

C

In the diagram of an insect-pollinated flower structure C is the anther. In an insect-pollinated flower, the anther is a vital reproductive structure located within the flower’s stamen. The anther is responsible for producing and releasing pollen, which contains the male gametes (sperm cells) necessary for fertilization. The anther typically consists of two lobes (microsporangia), each containing numerous pollen sacs (microsporangia), where pollen grains develop. These pollen sacs are filled with pollen mother cells that undergo meiosis to produce haploid pollen grains. As these pollen grains mature, they are released from the anther into the environment.

Insect-pollinated flowers often have anthers positioned in such a way that they come into direct contact with visiting insects. This facilitates the transfer of pollen from the anther to the body of the insect. Pollinators like bees, butterflies, moths, and beetles inadvertently pick up the pollen on their bodies as they forage for nectar, and then carry it to other flowers, facilitating cross-pollination.

The color, size, and shape of the anther can vary among different plant species, and these features can play a role in attracting specific pollinators. The anther’s position relative to the flower’s reproductive parts also helps prevent self-pollination and encourages outcrossing, which is important for genetic diversity in plant populations.

Question

 To which part of the flower is pollen transferred in pollination?
        anther
        B  petal
        C  sepal
        stigma

▶️Answer/Explanation

D

In pollination, pollen is transferred from the anther (male reproductive part) of one flower to the stigma (female reproductive part) of another flower. The stigma is specifically adapted to receive pollen and is a crucial part of the pollination process, leading to fertilization and the production of seeds.

Question

In addition to a suitable temperature, what else is necessary for seed germination?
       A  carbon dioxide and sunlight
       B  mineral ions only
       C  sunlight only
        water and oxygen

▶️Answer/Explanation

The correct answer is:

D. water and oxygen

In addition to a suitable temperature, seed germination requires water and oxygen. Water is essential to activate enzymes that initiate the metabolic processes needed for germination, while oxygen is necessary for cellular respiration, which provides the energy required for growth. Carbon dioxide and sunlight are important for later stages of plant growth but are not the primary requirements for seed germination. Mineral ions are also important for plant growth but are not specifically required for the initial process of seed germination.

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