Section 3-Plant Nutrition and Transport P1 Flashcards
Why do unicellular organisms not need transport systems?
they can diffuse directly into and out of the cell (through the cell membrane)
-the diffusion rate is quick because of short diffusion distances that substances have to travel
What substances do all cells in living organisms need to live?
e.g. plant cells need: water, minerals and sugars and to get rid of waste substances
Why do multicellular organisms need transport systems?
direct diffusion from the outer surface would be too slow, because of the large distance there would be to reach every cell
-so as a result plants have transport systems
What are the two main ways plants transport stuff about?
Xylem tubes (transport water and minerals) Phloem tubes (transport sucrose, amino acids)
What are the features of xylem tube?
- Xylem carry water and mineral salts
- they transport from the roots up the shoot to the leaves in the transpiration stream
What are the features of phloem tube?
- phloem transport sucrose and amino acids from where they are made in the leaves to other parts of the plant
- the movement of food substances around the plant is known as translocation
What is photosynthesis?
- the process that produces glucose in plants
- happens in the leaves of green plants, in the chloroplasts which contain chlorophyll which absorbs sunlight and uses the energy from light to convert CO₂ and H₂O into glucose, O₂ is also produced
What is the word equation for photosynthesis?
Sunlight
Carbon dioxide+water——–>glucose+oxygen
Chlorophyll
What’s the chemical equation for photosynthesis?
Sunlight
6CO₂ + 6H₂O———->C₆H₁₂O₆ + 6O₂
Chlorophyll
Why is photosynthesis an important process?
It converts light energy into chemical energy, which is stored in the glucose the chemical energy is released during respiration
What are the parts of a leaf?
- waxy cuticle
- upper epidermis
- palisade mesophyll layer(lots of chloroplast)
- spongy mesophyll layer
- vascular bundle, air space, stoma, guard cell
- lower epidermis
- waxy cuticle
How are leaves adapted for efficient photosynthesis?
- leaves are broad, large surface area exposed to light
- most chloroplasts are in palisade layer so they’re near the top to get the most light
- upper epidermis is transparent to let light through
- network of vascular bundles, transport vessels(xylem and phloem) deliver water and nutrients, take away glucose and support structure
- waxy cuticle reduces water loss by evaporation
- lower surface full of stomata which let CO₂ diffuse directly in the leaf
How does the limiting factor of photosynthesis depend on the conditions?
-limiting factor depends on the environmental conditions
E.g. Winter-temperature limiting factor, night-light limiting factor
What is a limiting factor?
Something which stops photosynthesis from happening any faster. E.g. Light intensity, CO₂ concentration and temperature can all be the limiting factor
How can light be a limiting factor to photosynthesis?
-if light intensity is increase the rate of photosynthesis will increase steadily but only up to a certain point(after that temperature or CO₂ will be the limiting factor)