Cells and plants

What is the difference between pollination and fertilization

What is the difference between pollination and fertilization

Pollination is the transfer of pollen from the anther of one plant to the stigma of the same or another plant. Fertilization is the joining of a sperm (from the pollen grain) with the egg in the ovule.

Define the term cell

The smallest structural unit in a living organism .

Cytoplasm

Enclosing and protecting the other parts of the cell /contents of a cell

Nucleus

The respiratory of genetic information and the cells control center

Cell Membrane

Provides protection from outside forces

Mitochondria

Generates chemical energy needed to power the cell

Chloroplast

Produce energy through photosynthesis

Vacuole

To help the storage and disposal of various substances

Why do plants need light?

So that photosynthesis can occur and the plant can gather nutrients

Water

So that photosynthesis can occur and so that the plant can carry nutrients from the soil

Air

So that photosynthesis can occur and the plant can gather nutrients

Place to grow

So that the plant doesn’t have to compete with its siblings for nutrients and a place to grow

What is sexual reproduction in plants

A pollinator moves pollen onto a suitable male stigma and travels down to the sepal which reaches the ovary and creates offspring

What is asexual reproduction

A plant with both male and female gametes fertilise themselves and create new offspring which is identical to the parent plant

Plant that uses sexual reproduction

Roses, mangoes, papaya

Plant that uses asexual reproduction

Garlic, strawberry, ginger

Advantages of sexual

Increased genetic diversity and immunity to diseases, Combination of beneficial traits.

Advantages of asexual

Faster and more efficient, higher chance of success, does not require finding a mate

Disadvantages of sexual

Excessive use of energy and time, takes more time, risk of genetic disorders

Disadvantages of asexual

Produces offspring with the same traits as the parent, vulnerability to diseases.

Label the parts

Ovule function

Houses the egg and receives pollen

Ovary

To prepare ovules for fertilisation and develop a seed-bearing fruit

Style

Assist with fertilisation by being the location where pollen tubes travel to deliver pollen to the egg

Stigma

Helps collect pollen

Pistil

Receives pollen

Anther

Helps the flower create pollen

Stamen

To produce the pollen grains which house male gametes

Filament

Supports the anther

Sepal

Protects rising buds by supporting petals when in bloom

Petal

To attract insects for pollination

Define pollination

To transfer pollen to a stigma, ovule, flower, or plant to allow fertilisation

What happens after pollen lands on a flower?

After pollen has landed on a stigma, it grows a pollen tube down through the style to the ovary. The pollen seed travels down this pollen tube and reaches the ovule. The fertilised ovule develops into a seed

What is self pollination

Pollination of a flower by pollen from the same flower or another flower on the same plant

What is cross pollination

Pollination of a flower by pollen from another flower on another plant that is of the same type

Example of self pollination

Peas, sunflowers, potatoes

Example of cross pollination

Apples, plums, pears

Advantages of self pollination

Pollen grains do not get lost in the process, pollination is not dependent on pollinators.

Advantages of cross pollination

A large quantity of seeds is produced compared to self pollination, it can result in new varieties. The offspring are healthier

Disadvantages of self pollination

A smaller quantity of seeds are produced, New variants cannot be created, Limits genetic diversity

Disadvantages of cross pollination

More pollen grains get lost in the process and do not reach the desired plant, pollination is more likely to fail, Potential to introduce undesirable traits

Explain which is better (self pollination or cross pollination) for the plant and why:

Cross-pollination is better for the plants as it produces more genetic diversity and lessens the chance of diseases and it is easier for plants to adapt to a new environment.

Describe a wind pollinated plant

Describe a insect pollinated plant

Stigma is sticky to capture pollen, stiff anthers inside the flower, brightly coloured petals

Explain why seed dispersal is necessary

So that seeds will not be competing with sibling plants for a space to grow and nutrients to survive.

Describe four methods of seed dispersal

water , wind, animal fur, explosion

Explain why it is not a good idea for seeds to grow close to the parent plant:

The sibling plants will have a hard time growing as they will need to compete for nutrients and a place to grow

Wind dispersal example

Dandelion

How are wind dispersal moved

The light and airy seeds disperse from the flower and use wind to carry them somewhere else

Water dispersal example

Coconut

How are water dispersal moved

Seeds have a spongy, fibrous outer shell which floats easily in water

Animal fur dispersal example

Rambutan

How are animal dispersal moved

They have hooks which cling onto animals fur and take them to a place away from the rest of the seeds

Explosion dispersal example

Balsam

How does explosion dispersal move

When the pods have dried, the pod bursts open to allow the seeds to scatter in many places

Two things only found in plant cells

Cell wall, chloroplast

Two things only found in animal cells

Centrioles, lysosomes

Explain the roles of stomata and veins

To move the nutrients and water that come from the stem of the leaf 

How does the leaf structure help photosynthesis

To collect easily nutrients like sunlight and water (flat and big)

How does the vein structure help photosynthesis

To move nutrients collected by the leaf

How does the stomata structure help photosynthesis

To allow for gas exchange to occur, so that when carbon dioxide enters the plant it converts it to oxygen and glucose

How does the chlorophyll structure help photosynthesis

To allow for photosynthesis to occur

Explain the method to test leaves for starch

1. Place the leaf in boiling water for 30 seconds – this kills it, stopping any further chemical reactions.

2. Place the leaf in boiling ethanol – removes the chlorophyll making the leaf paler in colour.

3. Dip the leaf in water – this softens it.

4. Spread the leaf onto a white tile and add iodine to test for the presence of starch.

Describe and explain photosynthesis: what is it and what does it need?

The process by which green plants transform light energy into chemical energy. During this process, light is captured by the leaf and used to convert water, carbon dioxide and minerals into nutrition for the plant to grow.

Write the word and symbol equation for photosynthesis

Carbon dioxide + water -> (light energy) Glucose + Oxygen gas 

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.

Reactants (yellow) and products (purple) of photosynthesis

Carbon dioxide + water -> (light energy) Glucose + Oxygen gas

Describe the process of respiration in plants

Oxygen from the air enters the leaf through stomata and reaches all the cells by the process of diffusion. The plant then uses the carbon dioxide for nutrition and releases oxygen.