Plants Flashcards
State the word equation for photosynthesis
Carbon dioxide + water -(light energy)-> glucose + oxygen
State the symbol equation for photosynthesis (all numbers with a ‘ are below the letter (opposite of squared))
6CO’2 + 6H’20 -(light energy)-> C’6H’12O’6 + 6O’2
What food do plants produce?
Glucose
Where does photosynthesis occur?
Chloroplasts
What does the chlorophyll do in photosynthesis?
Absorbs the light energy and converts CO’2 and water into glucose
What are the possible limiting factors in photosynthesis?
Light, CO2 and temperature
How does the rate limiting factor work in terms of photosynthesis?
You increase Light, CO2 or temp and the rate goes up until a certain point where it needs light CO2 or temp - new limiting factor
What temperature do plants denature?
About 45C
How can you make the right temperatures for plants to grow artificially?
Greenhouse - Trap sun’s heat, sun can hit the plants, water is provided. Often use a artificial light + heater in winter
How do plants use glucose in terms of respiration?
Glucose made on leaves, some used for respiration -> releases energy - rest of glucose converted into useful substances -> grow and build new cells
How do plants use glucose in terms of making cell walls?
Glucose -> Cellulose for making strong cell walls
How do plants use glucose in terms of making proteins?
Combined with nitrate ions -> amino acids -> proteins
How do plants use glucose in terms of storing fats/oils?
Turned into lipids for storing in seeds
How do plants use glucose in terms of storing starch?
Turned into starch -> stored in roots, stems, leaves.
What is good about the starch stored in the roots, stems and leaves of the plant?
Insoluble - Better for storing than glucose
Where do leaves and roots help exchange materials to?
Air and soil
Which side of the leaf is an exchange surface?
Underside
How are leaves adapted to exchange materials?
Packed with stomata, flattened shape -> large SA, air spaces increase SA, walls of cells form another exchange surface
What is the size of a stomata controlled by?
Guard cells
Where does CO2 diffuse into the leaf cell?
Air spaces then the cells
When would guard cells close?
When the leaf is losing water faster than the roots are making them
What would happen to the plant if there were no guard cells?
It would wilt
Where on the plant are most the mineral ions and water absorbed?
In the roots
What do roots have to increase the SA on them?
Root hairs
What does the phloem transport?
Food
What is a phloem made out of?
Columns of cells with small holes in the end
Where does the phloem transport food to?
Storage organs and growing regions
Which direction does the phloem transport food?
Both ways (Even though we got taught it was down)
What is the process called when the phloem transports food?
Translocation
What does the xylem transport and in which direction?
Water and minerals upwards
What is the xylem made out of?
Dead cells joined end to end, with no walls between them and no hole down the middle
What is the process called when the xylem moves materials around the plant?
Transpiration stream
What is transpiration?
The loss of water from the plant
What is transpiration caused by?
Evaporation and diffusion of water from inside the leaves
What happens as a result of transpiration in a plant, and what does the plant do because of it?
There is a shortage of water, the plant draws more up through the xylem
What can increase the rate of transpiration?
Heat, water, humidity and wind
What is auxin?
A plant growth hormone
Which areas of the plant does auxin control the growth of?
Tips of shoots and roots
What is phototropism?
The growth of an area of a plant due to a response to light
What is gravitropism?
The growth of an area of a plant due to a response to gravity
What is hydrotropism?
The growth of an area of a plant due to a response to moisture
Where is auxin produced and where does it move?
In the tips of a plant and moves backwards to stimulate cell elongation
What could happen if the tip of a shoot is removed?
Could stop growing as auxin has been removed
Which direction do shoots grow in relation to light?
Towards it
What happens in the position of the auxin when the shoot is exposed to light?
More auxin accumulates on the side in the shade so the plant curves towards the light
Which direction do shoots grow in relation to gravity?
Away from gravity
How can a shoot avoid growing towards gravity?
The auxin accumulates on the lower side making the plant curves away from gravity
Which direction do roots grow?
Towards gravity
Which direction do roots grow in relation to moisture?
Towards moisture
What makes roots grow towards moisture?
The plant produces more auxin on the side with more moisture causing the root to curve towards the moisture
What are selective weedkillers made out of?
Plant growth hormones
How do weedkillers work?
They interrupt the normal growth patterns
When a flowering plant reproduces sexually, what does it need to produce?
Male and female gametes
What is pollination?
The process where the male gametes are transferred to the female gametes
What is fertilisation in terms of sexual reproduction in plants, and what happens after it?
When the gametes fuse together. The ovules grow into seeds inside a fruit
What is cross-pollination?
When pollen is transferred from the anther of one plant to the stigma of a different plant
What is the male reproductive part of the plant called?
Stamen
What does the stamen consist of?
Anther and filament
What does the anther contain, and what do these materials do?
Pollen grains which produce sperm
What is the filament and what is the function of it?
It is the stalk that supports the anther
What is the female reproductive part of the plant called?
The carpel
What does the carpel consist of?
The stigma, style and ovary
What is the function of the stigma?
It is the end bit that the pollen grains attach to
What is the style and what is the function of it?
The rod like section that supports the stigma
What does the ovary contain?
The female gametes inside ovules
What happens in fertilisation in the plant? (State all the processes in order)
Anther produces male gametes in pollen grains.
These land on the stigma, which causes a pollen tube to grow down the style to the ovary
A male gamete nucleus then fertilises this ovule
Other male gamete nuclei fertilise endosperm nuclei -> Food sac for the embryo
Endosperm + female tissue of ovule make a seed
