Plants And Energy Flow Flashcards
What is the formula for photosynthesis?
Carbon dioxide + water > glucose + oxygen
What 4 things are needed for photosynthesis to happen?
Light to provide energy
Chlorophyll absorbs the energy, combines it with CO2 and water to make glucose (oxygen being a byproduct)
Carbon dioxide from the air
Water from the soil
What 6 things does glucose do in a plant?
Respiration - releases energy that enables them to convert the glucose into other things to build new cells and grow
Making fruits - glucose with fructose is turned into sucrose for storing in fruits
Cell walls - converted into cellulose
Making proteins
Stored in seeds - converged to lipids in seeds
Stored as starch - stored in roots, stems and leaves ready for use in winter when there’s no leaves
What is a plant’s rate of photosynthesis affected by?
The amount of light, CO2 and the temperature
What happens to the rate of photosynthesis if the light intensity is increased?
It will increase steadily until a certain point, where CO2 or temperature is now the limiting factor, so they need to be increased to raise the rate
What happens to the rate of photosynthesis if carbon dioxide is increased?
It will increase up until a certain point, where sunlight or temperature will then be the limiting factor
What happens to the rate of photosynthesis if temperature is increased?
It will increase the temperature up to a point, but if it gets too hot it will denature the enzymes and the rate of photosynthesis will drastically decrease
What is the layout of a leaf? (Cells and layers)
Waxy cuticle - to prevent water loss
Upper epidermis - to control interactions between inside and outside the leaf (CO2, sunlight, water)
Palisade mesophyll layer - Tightly packed layers of cells with chloroplast for photosynthesis
Spongy mesophyll layer - more chloroplasts but spongy air for diffusion
Lower epidermis
Waxy cuticle with stomata
What is transpiration?
The transfer of water through a plant
How are leaves adapted to their task?
Broad so large surface area exposed to light
Thin to allow easy diffusion
What do veins do in plants?
Transfer water and nutrients to parts in the plant
Carries food away from the leaves to the rest of the plant
Provides structural support
How does transpiration work?
Water is evaporated through the stomata in the leaves.
This creates a shortage in water in the leaves.
Therefore, water is brought up from the roots to the leaves so there’s a constant transpiration stream through the plant
What are the benefits of transpiration?
The constant stream of water keeps the plant cool
It provides the plant with a constant supply of water
It creates pressure in the plant, keeping it turgid
Minerals needed by the plant can be taken up with the water
what 4 things affect transpiration rate?
Light intensity - the brighter the light, the greater the rate as stomata closes when it’s dark so water can’t escape
Temperature - More evaporation of water means faster transpiration
Air movement - Wind increases transpiration rates as it carries the water vapour away so there’s a bigger concentration difference.
Humidity - If it’s dry it will happen quicker as there is less water concentration outside the leaf.
What adaptations do leaves have to prevent water loss?
A waxy waterproof cuticle
Stomata located on the underside of the leaf where it’s cooler and shady, so less evaporation
The more stomata, the more water loss there is, so plants in hot countries have less and smaller stomata
Why does a cell get turgid when there’s water in the plant?
Because water is drawn into the cell by osmosis, making it turgid as the water pushes against the cell wall, creating pressure
Why does a plant droop if it doesn’t have enough water?
The cytoplasm would start to shrink to conserve water and pulls away from the cell wall, making the cell wall droop
What are differences between xylem and phloem tubes?
Xylem - takes water and minerals up
Made of dead cells joined end to end with ‘no end’ walls
The sides are strong and stiff
They carry water from the roots in a transpiration stream
Phloem - Transports food (glucose)
Made of living cells with perforated end plates to allow stuff to pass through
Transport in both directions
The movement of food is known as translocation
What are the three main minerals of a plant?
Nitrates - make amino acids and proteins needed for cell growth.
Phosphates - Make DNA and cell membranes needed for respiration and growth.
Potassium - To help the enzymes needed for photosynthesis and respiration.
What happens to a plant if it doesn’t get the three main minerals?
Nitrates - it will be stunted and will have yellow old leaves
Phosphates - It’ll have poor root grows and purple old leaves
Potassium - poor fruit and flower growth and discoloured leaves
How does active transport work?
energy is used from respiration to pull in minerals against the concentration gradient
How are minerals and water taken into the roots?
Minerals are taken via active transport
Water is taken via osmosis
What is a trophic level?
A feeding level (on the food chain)
What does interdependent mean?
Each species relies on other species in an ecosystem for survival
