The Big Quiz On Plants! Flashcards
Where does photosynthesis take place?
In chloroplasts
Contains pigments and chlorophyll that absorbs light energy
What is the balanced symbol equation for photosynthesis ?
The opposite of respiration (aerobic respiration)
6CO2 + 6H2O
(Light energy) -> (chlorophyll)
C6 H12 O6 + 6O2
What does light energy do in photosynthesis?
Split water into oxygen and hydrogen ions
What are the 5 ways plants use their glucose?
- Respiration
- used in respiration to release energy
- energy to convert rest of glucose into other useful substances - Cell walls
- glucose turned into cellulose to make cell walls
- (especially of rapidly growing plants) - Stored in seeds
- glucose turned into lipids (fats and oil)
- then stored in seeds - Stored as starch
- glucose turned into starch
- starch stored in roots, stem and leaves
- used when photosynthesis doesn’t occur (at night)
- insoluble (can’t dissolve in water, doesn’t affect water concentration as it isn’t absorbing water) - Make proteins
- glucose mix with nitrate
- makes amino acids to make proteins
- used for growth and repair
What did Joseph Priestley prove?
Plants produce oxygen
1770s
How do plants gain mass?
By water
What happens if lit candle is put in a container ?
The fire would go out
What happens if a lit candle is in a container with a plant?
The fire would go out but re lit after a few weeks, due to the oxygen.
Where does the oxygen come from?
The water from photosynthesis
Plants photosynthesis
How can light slow down the rate of photosynthesis ?
Light provide energy for photosynthesis
Light level rising = Rate of photosynthesis increasing
How can carbon dioxide affect the rate of photosynthesis?
CO2 is needed for photosynthesis (plants use it)
More CO2 = higher rate of photosynthesis
How can temperature affect the rate of photosynthesis?
Photosynthesis works best in a warm temperature
Warmer temperature = greater rate of photosynthesis
If temp. is too high, enzymes of plant will denature
And photosynthesis will stop
Where is the vascular bundle found in a leaf?
It is right under the chloroplast
It is part of the spongy mesophyll layer
Leaves are thin, is this an advantage for photosynthesis ?
Yes
Carbon dioxide and water vapour diffuse faster as it is a shorter distance to reach the photosynthesising cells
What is the stomata?
Found in lower surface of leaves
Little holes to let gases In and out of leave
(Carbon dioxide, oxygen, water vapour)
What do guard cells do?
Surround each stomata
Controls when the stomata closes and opens
Allows it to control gas exchange
Why do leaves have air space in the spongy mesophyll layer?
Allows gases (CO2, O2) to move between stomata and photosynthesising cells.
What does “Big internal surface area to volume ratio” mean for a leaf?
That there is a LARGE SURFACE AREA for gas exchange in the leaf
What causes leaves to absorb light ?
The chloroplast which contains chlorophyll and photosynthetic pigments
Are all the photosynthetic pigments found in the chloroplast the same? Why?
No
Different pigments absorb different wavelengths of light
Plants can absorb most sun light energy and not let any go to waste
What are the 4 types of pigments found in chloroplast?
- Chlorophyll A
- absorb wavelength 400-450nm and 650-700nm - Chlorophyll B
- absorb wavelength 450-500nm and 600-650nm
(The pattern is that they go up by 50)
- Carotene
- absorb wavelength
400-550nm - Xanthophyll
- absorb wavelength 400-530 nm
Which cells are found in the palisade layer? (Near the top of leaf)
Cells that contain the most chloroplast
Can get most of the sunlight
How can light reach the palisade layer?
Above the palisade layer is the upper epidermis
Upper epidermis is TRANSPARENT
Light can go through it and reach the palisade layer
What are the 2 types of vascular bundles?
Xylem and phloem
What do the vascular bundles do? (3 jobs)
Deliver water and nutrient to every part of leaf
Take away glucose produced by photosynthesis
Help to support leaf structure
What does turgid stand for ?
Plant cells being swollen due to osmosis
What does flaccid stand for in a plant cell?
When plant cell loses water and lose their turgor pressure
What do phloem tubes (vascular bundle) transport?
Food substance
(Mainly sugar)
Food substance can go either way in the tube (up and down)
What are phloem tubes?
Vascular bundle
Made of columns of living cells with perforated (pieces holes) end-plates
End-plate that have holes allow stuff to flow through
What is translocation?
Movement of food substances around plant
By the phloem tube
What do xylem vessels do?
Take water and minerals from root and UP the shoot
From shoot to leaves in the TRANSPIRATION STREAM
What are xylem vessels made of?
Dead cells joined
No end walls between dead cells
Have a lumen (hole in the middle)
Thick side walls made of cellulose
(Strong and stiff which supports plant)
What is root cross-section in a vascular bundle?
Root have to resist crushing as they push down through the soil
Xylem is found in centre to give root strength
Phloem around the xylem
Vascular bundle surround them
What is stem cross-section in a vascular bundle?
Stems need to resist bending
Phloem is around the outside of stem
Xylem in the middle of stem
What is a leaf cross-section in a vascular bundle?
Leaves need support
Xylem and phloem make up a vein that supports the leaf
How do plants take in water and by what?
Root hair in plants (long hairs that stick out in soil) take in water by osmosis
How do root hair take in water?
By osmosis
Millions of microscopic hair in root will stick out in soil
Therefore, big surface area for absorbing water
What is transpiration?
The loss of water from a plant
What is transpiration caused by?
Evaporation and diffusion of water vapour from inside the leaf
How can transpiration benefit the plant?
Transpiration (water leaving the plant) means there is a higher concentration of water in soil that in plant
This will draw in MORE water inside root
Therefore constant transpiration stream of water through plant
What are the advantages of transpiration in a plant ? Name 4.
- Keeps plant cool
- there’s a constant stream of water from the ground - Provides plant with constant supply of water for photosynthesis
- Water creates turgor pressure, helps support the plant and stop it being flaccid
- Minerals needed can be brought up from soil constantly along with the water
How can the rate of transpiration be increased by an increase in light intensity?
Brighter light = greater transpiration rate
!!remember that transpiration is plant LOSING water!!
Stomata closes when it gets dark and photosynthesis doesn’t happen when it gets dark
Therefore CO2 isn’t let in, and water can’t escape.
Too much water in plant so it will diffuse
How can an increase in temperature increase the rate of transpiration ?
Warmer temperature = faster transpiration
Warmer water particles have more energy
Evaporate and diffuse faster out of the stomata
How can an increase in air movement increase the rate of transpiration ?
More wind = more transpiration
If water is still on surface of leaf , there’s an isotonic solution (inside and outside of leave has same water concentration)
By wind, water is swept away across the leaf (low concentration of water particles on leaf)
Leaf has more water
Water will come out of leaf by diffusion
How would a decrease in air humidity increase the rate of respiration?
The dryer the air = the faster the transpiration
Humid air contains water
Not much difference (isotonic solution) of water concentration inside and outside of cell
The dry air means less water outside the leaf and more water inside the leaf.
Leaf will diffuse its water outside - transpiration
What is above the upper epidermis in a plant?
The waxy cuticle which is waterproof
Where are stomata mostly found and why?
In the lower epidermis (underneath the leaf)
As it is cooler and darker
Helps control diffusion and transpiration
What happens if a leaf has a large and many stomata?
Plant will lose a lot of water compared to other plants with fewer stomata
Plants in hot climates have few stomata, explain why?
They need to save water, therefore have small and less stomata
No stomata at the surface of leaf (upper epidermis)
Just under
When does a stoma close?
When it had become turgid (a lot of water into the cell)
Blocks the gap in the middle, letting no substances in or out
When does a stoma open?
When it has become flaccid (less water in cell)
Leaves a gap in the middle, letting substances in and out
What causes the stomata to go flaccid or turgid?
The guard cell
It has a special kidney shape which opens and closes when turgid or flaccid
If a stomata open, what happens?
Gases are let in and out for photosynthesis
Open during the days
What happens to a stoma at night ?
The stoma closes
Allows conservation of water
What are the 4 main minerals plants need?
Nitrate-
Contain nitrogen to make amino acids (make proteins)
Needed for cell growth
Phosphate-
Contain phosphorus to make DNA and cell membrane
Needed for respiration and growth
Potassium-
Help the enzymes needed for photosynthesis and respiration
Magnesium - Making chlorophyll (for photosynthesis)
What happens if a plant doesn’t have their 4 main minerals?
Nitrate -
Growth will be poor
Will have yellow older leaves
Phosphate-
Poor root growth
Discoloured older leaves
Potassium-
Poor flower and fruit growth
Discoloured leaves
Magnesium -
Have yellow leaves
Where can potassium, nitrate, magnesium and phosphate be found for a plant ?
In the soil
How do plants take in minerals from the soil?
From the root hairs by active transport
Why can’t root hair take in minerals from soil by diffusion?
Root hair usually have a higher concentration of minerals that the soil
If it was diffusion, root hair would diffuse minerals to soil - as they have a higher concentration
Therefore root hair get their minerals from soil by active transport
What is active transport ?
For root hair to get their minerals from soil.
Active transport uses energy from respiration
Helps plant pull minerals into root, bearing diffusion
