Plant Reproduction Flashcards
What is asexual reproduction?
A process by which organisms reproduce without the formation and fusion of gametes
Results in genetically identical offspring, known as clones
What type of offspring does asexual reproduction produce?
Genetically identical offspring, known as clones
Asexual reproduction occurs in lower-level animals and some plants
What is sexual reproduction?
Reproduction involving the fusion of specialised sex cells or gametes which fuse and form a zygote
The zygote develops into a new organism, genetically different from its parents
What is fertilisation in sexual reproduction?
The process when male and female gametes fuse to produce a zygote
Occurs in both animals and plants
How do offspring differ in sexual reproduction compared to asexual reproduction?
Offspring in sexual reproduction are genetically different from each other and from parents
Asexual reproduction produces offspring that are genetically identical to the parent
What is the main difference in the number of parents between asexual and sexual reproduction?
Asexual reproduction involves 1 parent; sexual reproduction involves 2 parents
Affects genetic variation in the offspring
What type of cell division produces gametes?
Meiosis cell division
This process is used in sexual reproduction
What type of cell division produces offspring in asexual reproduction?
Mitosis cell division
No gametes are produced in asexual reproduction
What are the advantages of asexual reproduction?
No need to find a partner, more resource efficient, rapid reproduction
Produces large numbers of offspring near the parent
What are the disadvantages of asexual reproduction?
No genetic variation, all offspring are identical to the parent
Susceptibility to diseases can affect all offspring
Fill in the blank: In sexual reproduction, offspring show _______.
variation
Offspring have different genes from parents
True or False: Asexual reproduction results in offspring that show variation.
False
Offspring are genetically identical to the parent
What is a runner in asexual reproduction?
A side branch that produces plantlets at the end
Examples include spider plants and strawberries.
What role do bulbs play in plant reproduction?
They serve as underground food storage organs that develop into new plants
Examples include daffodil bulbs and onions.
What is a stem tuber?
A food storage organ at the end of underground stems that can grow new plants from buds called eyes
An example is the potato.
How is cloning a plant through cuttings performed?
By cutting off a branch, removing lower leaves, and planting the stem in damp compost
Planting hormones in rooting powder can encourage new roots to develop.
What additional component do rooting powders contain?
A fungicide to prevent the shoot from rotting
This is important for successful rooting of cuttings.
What is the purpose of covering cuttings in a clear plastic bag?
To keep them moist and warm, encouraging growth and preventing water loss
This is crucial when the cutting cannot replace water without roots.
What is the carpel in flowering plants?
The female part of the flower
What is the stamen in flowering plants?
The male part of the flower
What is the function of petals in a flower?
To attract insects and act as a landing platform
What is the role of sepals in a flower?
To surround the petals in the bud and protect the flower
What does the anther produce and release?
Pollen, which is the male gamete
What is the function of the filament?
Supports the anther
Where does pollen land in the female reproductive organ?
On the stigma
What connects the stigma to the ovary?
Style
What does the ovary produce?
Ovules
What structure contains the female nucleus?
Ovule
What is pollination?
The process where male gametes (pollen) travel to the stigma
What happens during self-pollination?
Pollen from a flower lands on its own stigma
Why is self-pollination undesirable?
It reduces variation in the population and can leave plants vulnerable to disease
What is cross pollination?
Delivering pollen to a different flower, increasing genetic variation
How can plants prevent self-pollination?
By having their anthers and stigmas ripening at different times
What is one adaptation of plants for insect pollination?
Large, colorful petals to attract insects
What do nectaries secrete to attract insects?
Nectar
What characteristic do pollen grains have in insect-pollinated plants?
Spiky or sticky pollen grains that stick to insects
What is a feature of the stigma in insect-pollinated plants?
Sticky to catch pollen from insects
What adaptation do wind-pollinated plants have in their flowers?
Small, dull flowers that do not need to attract insects
What is the position of anthers in wind-pollinated plants?
Dangling outside the flower to catch the wind
What is a characteristic of the stigma in wind-pollinated plants?
Large and feathery to catch pollen
What type of pollen grains do wind-pollinated plants produce?
Light, small pollen grains that can be blown in the wind
True or False: Wind-pollinated plants have a strong scent to attract insects.
False
What is the first step in the fertilisation process in plants?
The male gametes in the pollen grains land on the surface of the stigma
This process is known as pollination.
What grows through the style towards the ovary during fertilisation?
A pollen tube
The pollen tube is crucial for delivering the male nucleus to the ovule.
How does the pollen tube enter the ovule?
It wraps around and the tip of the pollen tube enters the ovule from the bottom
This allows the male nucleus to transfer into the ovule.
What happens to the male nucleus during fertilisation?
The male nucleus fuses with the ovum (egg cell) nucleus
This fusion results in the formation of a zygote.
What develops from the zygote after fertilisation?
An embryo plant
The embryo plant includes a small root (radicle) and shoot (plumule).
What are cotyledons and endosperm?
Food store containing starch
They provide energy for germination until the plant can photosynthesize.
What does the ovule wall become?
Seed coat (testa)
The seed coat protects the developing seed.
What does the ovary wall develop into?
Fruit coat
The fruit coat varies from species to species.
Why is seed dispersal important?
To avoid competition with the parent plant for resources
Resources include water, space, sunlight, mineral ions, and oxygen.
Name three methods of seed dispersal.
- Water (e.g., coconut)
- Wind (e.g., sycamore)
- Animals (e.g., burdock)
Seeds may be dispersed inside fruit or alone.
What is germination?
When the seed starts to grow
A seed remains dormant until conditions are right for growth.
What initiates the germination process?
The seed absorbs water from the soil through the micropyle
This absorption leads to the softening and splitting of the testa.
What happens to the enzymes during germination?
They are activated as they are in solution
Enzymes break down food reserves in the seed.
What is the role of amylase in germination?
Breaks down stored starch into maltose
Maltase then converts maltose into glucose.
What is glucose used for during germination?
- Respiration
- Building up cellulose for new cell walls
Glucose provides energy for growth.
What happens to the seed’s mass during respiration?
The seed loses mass due to CO2 released
This loss occurs as the seed metabolizes stored nutrients.
What evidence indicates that germination has occurred?
The radicle or plumule emerging from the seed
This is a sign that the seed has started to grow.
What are the factors needed for germination?
Water, oxygen, and warmth
This is often abbreviated as WOW.
What role does water play in seed germination?
Activates germination by allowing enzymes to perform respiration and digestion
Water must be in solution to collide with substrate molecules.
What must happen for enzymes in the seed to function during germination?
They must be in solution
This allows enzymes to collide with their substrate molecules.
What does the absorption of water by the seed indicate?
It activates germination
This is a critical first step in the germination process.
How does high osmotic concentration impact seed germination?
It prevents enough water from being absorbed
If the water is too salty, it disrupts the osmotic concentration gradient.
What is the role of oxygen in seed germination?
Needed for respiration which occurs in the seed during germination
Oxygen transports the energy from food for growth.
How does warmth affect enzyme action during germination?
Enzyme action is temperature dependent; more enzyme and substrate collisions occur in warmer conditions
Germination tends to happen faster in warmer conditions, but excessive warmth can lead to mould growth or enzyme denaturation.
What experimental conditions were tested for seed germination?
Wet or dry cotton wool, water or no water, mustard or cress seeds
Test tubes were used to assess the impact of these variables.
What were the results in the tube with light, oxygen, water, and warmth?
Germination with lots of strong green shoots and long roots growing
Water activates enzymes and oxygen is used in respiration to release energy for growth.
What happens to seed growth in the absence of warmth?
Growth rate is very slow; only small yellow shoots and short roots appear
This is due to slow enzyme activity at low temperatures.
What occurs in the tube with oxygen, water, and warmth but no light?
Germination occurs; shoots are tall but yellow due to lack of light
This proves that light is not necessary for germination.
What is the outcome of using pyrogallol in the experiment?
No germination occurs due to lack of oxygen
Pyrogallol absorbs oxygen; without it, there is no energy for growth.
What happens when seeds are placed in a light and warm environment without water?
No germination occurs; enzymes aren’t in solution
Without water, starch stores are not broken down, and respiration doesn’t occur, leading to no energy for growth.
