Plants Flashcards
Chemical equation for photosynthesis
6CO2 + 6H2O -> C6H12O6 + 6O2
How is glucose used for storage?
Glucose is soluble in water and if it were stored as glucose in plant cells it would dissolve and affect the water balance of the plant. Instead it is converted into starch which is not soluble.
How is glucose used in respiration
Glucose is broken down using oxygen to provide energy for cells.
How is glucose used to create the necessary amino acids for plants
Glucose combines with Nitrates and other mineral ions from the soil to form amino acids which are the built up into proteins.
How is glucose used to strengthen cell walls
Plants and algae build up glucose into more complex carbohydrates (like cellulose) which are used to strengthen the cell walls
How is glucose used to create energy stores
Glucose can be used to build up fats and oils (lipids) which act as energy stores and can be used in seeds to give them the energy they need to germinate
Word and chemical equation for respiration
Oxygen + glucose -> carbon dioxide+ water vapour + energy (ATP)
6O2 + C6H12O6 -> 6CO2 +6H2O + energy(ATP)
Why do you destarch leaves before testing them for starch?
So you don’t test already present starch
How do you test for starch in a leaf
Boil the leaf and then dip it in ethanol to stop metabolic reactions and remove chlorophyl. Dip the leaf back into hot water to soften it, then lay out the leaf on a white tile. Cover the leaf in iodine solution. If starch is present it goes blue black if there is no starch it will stay yellowy orange
Hydrogen carbonate indicator shows the presence of what?
Carbon dioxide
What colour does hydrogen carbonate indicator go when showing positive and negative results?
Yellow if there is more co2 stays red if there is still an atmospheric level of co2 and goes purple if there is less co2
Word equation for photosynthesis
Carbon dioxide + water -sunlight trapped as chlorophyl–> glucose + oxygen
What solution removes co2
Potassium hydroxide
Why do plants need nitrate ions and what does a deficiency of nitrate ions cause?
Building proteins and growth
Deficiency: poor growth and yellow leaves
What do plants use magnesium ions for and what does a deficiency of magnesium ions cause?
Used for photosynthesis (magnesium is what makes chlorophyll green and is in chlorophyll)
Deficiency: yellow leaves
What are stomata?
Small holes in the epidermis of leaves where gas exchange happens
What does the xylem transport?
Water
What is water used for in plants
Photosynthesis
Germination
Keeping cells turgid
Transport
Why does water evaporate (by diffusion) from the leaf surface? (Transpiration)
To set up a concentration gradient
Describe the transpiration stream
Water moves out of roots and into xylem by osmosis. The water then moves up the xylem due to the tension due to water loss and the cohesion and capillarity of water. Water then moves from the xylem into the pal aside cells by osmosis.
What is capillarity?
The adhesion(sticking) of water to the walls of a small tube
How does humidity affect transpiration?
Low humidity = high transpiration as there is a higher water potential difference.
How does temperature affect transpiration?
High temp = high transpiration as water molecules have more kinetic energy
How does wind speed affect transpiration?
High wind speed = high transpiration because it blows humidity and water away from leaf to increase water gradient
What is the xylem made up of?
Dead cells and rings of lignin which strengthens/thickens the xylem wall
Why does an airtight seal need to be made when using a potometer
Because otherwise the transpiration pull and cohesion between water molecules is broken
What does the phloem transport?
Sucrose and other organic compounds. It flows up and down.
What are the cell walls of the phloem made up of?
Cellulose
If you shine light from one direction onto a plant where will the auxin go?
To the dark side
What is auxin?
A plant hormone for plant growth regulation. Responsible for geotropism. It causes cell elongation
In a shoot a high concentration of auxin causes
Cell elongation
In roots a high concentration of auxin does what?
Stops cell elongation
What is phototropism?
A response to light (positive response is growth towards stimuli, negative is growth away)
What is geotropism or gravitropism?
Response to gravity. (Positive is growth towards stimuli and negative is growth away.)
What is asexual reproduction
Only having one parent. Cells make copies of themselves and all genes are passed on. The offspring is identical to its parent (clone)
What is a zygote?
The first cell after fertilisation when the diploid number has been restored
Half a diploid is a….
Haploid
What is a disadvantage of asexual reproduction?
It reduces the gene pool
What does a zygote undergo to become and embryo, and what does an embryo undergo to become the offspring?
Mitosis
What do plants use nitrate ions for?
Building proteins and growth, all amino acids contain nitrogen and amino acids build proteins.
What do plants use phosphate ions for?
Respiration and growth as phosphate ions are in components of DNA molecule and cell membranes
What do plants use potassium ions for
Respiration and photosynthesis as they must be present for photosynthesis and respiration enzymes to work
What do plants use magnesium ions for
Photosynthesis as chlorophyll molecules contain magnesium.
What does a deficiency of nitrate ions cause
Poor growth and yellow leaves
What does a phosphate deficiency cause
Poor root growth and discoloured leaves
What does a potassium deficiency cause
Poor flower and fruit growth and discoloured leaves
What does a magnesium deficiency cause
Yellow leaves
Describe colour change in hydrogencarbonate indicator
At atmospheric CO2 level it is red
When there is increasing CO2 it turns orange then yellow
When there is decreasing CO2 it turns magenta then purple
When does respiration happen
During the day and night.
What does the net exchange of CO2 and oxygen depend on?
Light intensity
