B2 Flashcards
What’s an autotroph
an organism that makes it own food from inorganic substances
What’s an heterotroph
an organism that cannot make its own food and eats food and energy by taking in organic substances.
What troph is a plant
an autrotroph it makes its own food from inorganic substances
What process is required for all organisms to stay alive
nutrition the process of taking in food and converting it into energy and other vital nutrients required for life
What is nutrition
the process of taking in food and converting it into energy and other vital nutrients required for life
What is photosynthesis
the process of converting energy from light into carbohydrates for nutrition for plants
Adaptations for photosynthesis by plants
thin leaf blades and large surface area. Thin leaf blades can maximise the penetration of light so more chloroplasts can be exposed to light energy. Large surface area maximises amount of light absorption.
Leaf section diagram from top to bottom
There’s the waxy cuticle, upper eperdermis, then the palisade mesophyls, the spongy mesophyl layer, inside the spongy mesophyl layer there’s the vasucular bundle containing the xylem and phloem, and under the spongy mesophyl layer is the lower eperdermis which has the stomata and guard cells.
How does the upper eperdermis adapt leaves for photosynthesis
Thin cuticle: Reduces light reflection and allows gas exchange
Compact cells: Minimizes space, allowing light to reach photosynthetic cells
How does the waxy cuticle adapt leaves for photosynthesis
It decreases water loss to maintain humidity of plant and transparent so light can reach photosynethetic cells
How does the palisade mesophyl adapt leaves for photosynthesis
Contains main chloroplasts for maximum light absorption and cells are tightly packed next to each other
How does the spongy mesophyl layer adapt leaves for photosynthesis
It has large air spaces that allows diffusions of gases into the photosynthetic leaves such as co2
How does vascular bundle adapt leaves for photosynthesis
it provides a xylem and phloem
Xylem: Transports water and minerals from roots to photosynthetic cells
Phloem: Transports sugars and organic compounds produced by photosynthesis
How does Lower eperdermis adapt leaves for photosynthesis
Stomata: Regulates CO2 entry for photosynthesis and water loss
Guard cells: Controls stomatal opening and closing
What does a stomata let in and out o fthe leaf
It lets in carbon dioxide and water vapour and oxygen produced out of the plant
What is a stomata
a opening in surfaces of plants which allow gases in or out of the plant.
What do guard cells do to stomata
it widens or reduces the opening and controls the gas exchagne
What is necessary for photosynthesis
Carbon dioxide
What is used in respiration for plants
Oxygen
What part of the plant can photosynthesize
anything green as it contains a pigment chlorophyll that traps light energy and converts it to chemical energy
What are the raw materials of photosynthesis (required for photosynthesis to take place)
Carbon dioxide and water
How does water enter the leaf
osmosis through the soil
How does carbon dioxide enter the plant
diffusion in the leaves
What is the prouduct of photosynthesis
glucose also oxygen which diffuses out of the stomata in to the atmosphere.
What is the energy source for photosynthesis to take place
light energy from the sun
Word equation of photosynthesis
Carbon dioxide and water –> Oxygen and glucore
Balanced symbol equation for photosynthesis
6CO^2+H^2O —>C^6H^12O^6+6O^2
What can glucose be turned into or used for
Starch as a energy store
Cellulose to build cell walls
Used in respiration to provide energy
Sucrose for transport in the phloem this way it doesn’t impact water concentration gradients
Nectar to attract insects for pollination thus reproduction
How can you tell if a plant has been photosynthesizing?
test it for starch presence
How to test for starch presence in a leaf
1)You must boil it to soften which breaks down the waxy cuticle
2) Ethanol is added to remove the color
3) Leaf is washed to remove the ethanol
4) Then starch test you put the leaf in iodine solution if there’s dark blue the leaves have been photosynthesizing
What happens if there’s no light ot motr light
no photosynthesis no starch no glucose, faster photosynthesis
What happens if a place is exposed to more carbon dioxide
it has more photosynthesis thus more glucose produced.
What happens if a plant is placed at a higher temperature
it will increase the photosynthetic rate
In what lighting is photosynthesis the fastest at
red and blue lighting
IN what lighting is photosynthesis the slowest at
green lgihting
What affect does light source have on photosynthesis
the further the light source is from the plant the slower the rate of photosynthesis
What is hydrogencarbonate indicator
it is used to measure carbon dioxide levels in solutions it becomes more or yellow in higher levels of CO^2 and red to deep purple as lower levels of CO^2
What minerals are required by plants
Nitrates, magnesium, phosphates, and potassium
Why is nitrates required by plants
as they combine with glucose to make amino acids whcih make protiens. If there’s not enough nitrates, the growth of the plant will become stunted, a weak stem, and death
Why is Magnesium required by plant
as they form parts of the chlorophyl molecule if it isn’t suffiecient plants will turn yellow and can’t photosynthesize effectively leading to poor growth
Why is potassium required by plants
it must be present for photosynthesis and respiration without there’s would be sdiscolored leaves and poor flower blossoms
Why is phosphate required by plants
it’s a component of DNA and cell membranes with out it there’s poor root growth and leaves aren’t green
2 substances which need to move from the roots to the leaf
water and mineral ions
How is water and mineral ions transported from the roots to the leaf
by the xylem
What two substances are created in the leaf that need to be transported elsewhere
glucose and amino acids
What is the path of mineral ions as they enter a leaf
they enter the root hair cell, then root cortex cell, xylem, up the root, and then transpires out of the leaf
How to identify xylem and phloem
xylem is always thicker than phloem
What adaption does root hair cells have
they have a large surface area of root hairs which increase their uptake of water and mineral ions
What’s osmosis
the movement of water across a semi-permerable membrane from an area of low to high water potential
How much of the water plants absorb are used in photosyntheis
10%
What is transpiration
loss of water vapour from plants
What functions does water have in cells
for turgor, photosynthesis, but 90% leaves via. stomata it evaporates in the air spaces of the spongy mesophyl exiting as a gas
What factors affect transpirtation
Humidity increases transpiration dereases
Wind speed increases transpirtation incresases
Temperature increases transpiration increases
Light intensity increases transpirtation icnreases
What does a potometer measure
upatake of water by a shoot of plant
What theory is a potometer based on
a transpiration system in plants, as once the water transpires it’s replaced by the water uptake so it’s used to measure transpiration
How to read a potometer
Zero the potometer
Ensure the bubble is at the starting point
Start a timer
Note the distance the bubble travels
Calculate transpiration rate
Use formula: Transpiration rate (mm/hr) = Distance traveled (mm) / Time (hr)
What is wilting
when plants lose water from cells, this leads to plants becoming not upright
Causes of wilting
reduction in water in plant leading to low turgor and vacuole shrinks leading to flaccid and soft plant cells
In the dark can plants photosynthesize
no, bc. without light energy there’s no energy for a reaction whcih is photosynthesis to occur
What is translocation
Movement of sucrose and amino acids in the phloem from a source to a sink where it’s produced and then where it’s utilized
Examples of sources in plants
Leaves,
Examples of sinks in plants
Growing shoots, leaves
