Chapter 17: Reproduction in plants

Question 1

Define asexual reproduction

Answer 1

Process resulting in the production of genetically identical offspring from one parent, without the fusion of nuclei of gametes.

Question 2

What are 4 advantages of asexual reproduction?

Answer 2

1. Faster method of producing offspring as compared to sexual reproduction
2. Only one parent is required
3. Fusion of gametes is not required
4. All the beneficial qualities are passed on to the offspring from the parent

Question 3

What is a disadvantage of asexual reproduction?

Answer 3

1. No genetic variation in the offspring. Hence species are not well adapted to changes in the environment

Question 4

Define sexual reproduction

Answer 4

Process resulting in the production of genetically dissimilar offsprings, with the fusion of the nuclei of gametes to form zygote

Question 5

Advantages of sexual reproduction

Answer 5

1. Greater genetic variation in the offspring, leading to species that are better adapted to changes in the environment
2. Offspring may inherit beneficial qualities from both parents

Question 6

Disadvantages of sexual reproduction

Answer 6

1. Two parents are required
2. Fusion of gametes is required.
3. Slower method of producing offspring as compared with asexual reproduction

Question 7

What are the characteristics and functions of the petal

Answer 7

In insect-pollinated flowers, the petals are:
1. Brightly coloured to attract insects for pollination
2. Provide a platform for insects to land
3. Have nectar guides to guide insects to the nectar
In wind-pollinated flowers, the petals are:
1 Small and dull in colour

Question 8

What are the characteristics and functions of the sepal

Answer 8

Sepals are modified leaves which enclose and protect the other parts of the flower in the bud stage

Question 9

What are the characteristics and functions of the Anther (male)

Answer 9

The anther produces pollen grains
Pollen grains have two nuclei:
1. Generative nucleus (involved in sexual reproduction)
2. pollen tube
_________________
1. The anther has two lobes which each lobe containing pollen sacs.
2. Pollen sacs contain pollen grains.

Question 10

What are the characteristics and functions of the filament

Answer 10

Is the stalk that holds the anther in a suitable position to disperse the pollen grains.

Question 11

What are the characteristics and functions of the stigma(swollen structure at the end of the style)

Answer 11

1. Receives the pollen grains.
2. Mature stigma secretes a sugary fluid that stimulates the pollen grains to germinate.

Question 12

Define self pollination

Answer 12

Transfer of pollen grains from the anther to the stigma of the same flower or different flower on the same plant.

Question 13

What are some advantages to self pollination?

Answer 13

1. Only one parent plant is required
2. The offspring inherits its genes from the parent plant, and thus it is more likely that beneficial qualities are passed down to the offspring.
3. Does not depend on external factors such as insects or wind for pollination
4. Since anthers are close to the stigmas of the same flower, there is a higher probability that pollination will occur, as compared to cross-pollination
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Question 14

What are some disadvantages to self pollination

Answer 14

1. Less genetic variation in the offspring as compared with cross-pollination. Thus the species is less well adapted to changes in the environment.
2. The probability of harmful recessive alleles being expressed in the offspring is higher as compared with cross-pollination

Question 15

Define cross-pollination

Answer 15

Transfer of pollen grains from the anther of one plant to the stigma of a flower in another plant of the same species.

Question 16

What are some advantages of cross-pollination

Answer 16

1. More varieties of offspring can be produced as there is greater genetic variation. This increases the chance of species surviving changes in the environment
2. Offsprings produced may have inherited beneficial qualities from both parents
3. The increased possibility of harmful recessive alleles being expressed in offspring is lower as compared with self-pollination

Question 17

What are some disadvantages of cross-pollination

Answer 17

1. Two parents are required
2. Depends on external factors like wind or insects for pollination
3. Since pollen grains have to be transferred from the anther of a plant to the stigma of another plant, there is a lower probability that pollination will occur, as compared to self-pollination.