Which embryonic cell layer is involved in secondary growth?
What is the difference between a leaf and a leaflet?
Leaf has a bud in its axil but a leaflet does not
How does transport by bulk or mass flow through tubes work?
This type of flow is driven by the pressure difference between the 2 ends of the tube and is inversely related to the cross section of the tube
Examples: flow of water and dissolved mineals through xylem vessels or of blood through blood vessels are examples of mass flow
How to make protein from simple carbohydrates?
Make amino acids by adding N, S
Turn amino acids into proteins
How to make membranes from simple carbohydrates?
Make lipids by adding P and/or S
Turn lipids into phospho and sulfo lipids
Turn this into membranes
How to make nucleic acids from simple carbohydrates?
Make nucleotides by adding N and P
Make nucleotides to nucelic acids
How are photosynthetic products transported?
Mainly sugars - transported from source tissue (leaves) to the sink tissues (growing organs) through the phloem
Both xylem and phloem are involved
What is the process by which photosynthetic products are transported?
Source leaves are rich in sugar and load sugars into phloem cells which absorbs water from xylem through osmosis and develop high turgor pressure. Sink cells unload sugars from phloem cells. The water in the phloem cells returns to the xylem. Thus transport of photosynthetic products in the phloem is purely pressure-driven
What is phloem sap composed of?
Mostly sugars (65%)
What is an essential element in plant nutrition? (3 criteria)
1. Plants cannot complete life-cycle without the element. Completion of life cycle includes reproduction.
2. The element can not be replaced by a similar element, meaning another element from the same group in the periodic table.
3. Its lack/absence must produce a specific deficiency symptom.
What non-mineral elements do plants obtain?
Get H, C, and O from water or atmosphere
What macro-nutrients do plants get from soil?
N, K, Ca, Mg, P, S and Si
What micro-nutrients do plants get from soil?
Cl, Fe, B, Mn, Na, Zn, Cu, Ni, and Mo
Which nutrients are mobile within the cell?
N, K, Mg, P, Cl, Na, Zn, Mo
Which nutrients are immobile within the cell?
Ca, S, Fe, B, Cu
What are the intercellular spaces between adjacent cells in plants called?
How are cationic (positive) minerals adsorbed?
Due to their positive electrical charges are adsorbed onto the surface of clay particles which are negatively charged.
How are anionic (negative) minerals adsorbed?
Generally leached down with rain water and are less stably available to the root
Why is nitrogen fixation important?
no animal or plant can get it
most animals and plants suffer from N-deficiency.
However, some bacteria can get it.
So plants and bacteria have a symbiotic relationship
Specific bacteria living in root nodules fix N2 gas into nitrogenous compounds which are then transported to all parts of the plant. Bacterium gets photosynthates from the plant.
What are bacteroids?
bacteria each surrounded by the host cell plasma membrane
What are mycorrhizal fungi?
Roots of some gymnosperms and many angiosperms form mutually beneficial associations with certain fungi.
The plant gets minerals from the fungus and the fungus gets carbon compounds from the plant
What is ectotrophic mycorrhizal fungus?
Fungus may live in apoplast region, never entering the cytoplasm of the host cell
What is vesicular-arbuscular mycorrhizal fungus?
Fungus may actually reside inside the host cells
Where do some plants living in nitrogen-poor habitats obtain nitrogen?
Get nitrogen supplements from insects
To a lesser extent, phosphorous is also obtained
These are carnivorous plants
The plant secretes enzymes to digest the insect, only insect exoskeleton is left at the end.