Notes : 4.7 - 4.12 Properties of Plants Flashcards
Label the structures within the chloroplast.
Label and describe the function of this structure.
-The vacuole contains the cell sap.
- Vacuoles keep the
cells turgid.
- The tonoplast controls what enters and leaves the vacuole
Label and describe the function of this structure
- The outer most layer of the cell.
- Acts as an adhesive, sticking adjacent plant cells together.
What structure is this ?
Amyloplast
Plant Cell Wall Structure
● Middle lamella- outer cell wall layer that contains polysaccharides called pectins. Pectins aid in cell adhesion by helping the cell walls of adjacent cells to bind to one another.
● Primary cell wall*- layer formed between the middle lamella andplasma membranein growing plant
cells. composed of *cellulose microfibrils contained within a gel-like matrix of hemicellulose fibres and pectin polysaccharides. The primary cell wall provides the strength and flexibility needed to allow for cell growth.
● Secondary cell wall- layer formed between the primary cell wall and plasma membrane in some
plant cells. This rigid layer strengthens and supports the cell. some secondary cell walls contain lignin.
What is Lignin
Lignin is a thick, woody substance which is found in the cell walls of xylem and schlerenchyma cells and provides strength to the plant stem.
Lignin strengthens the cell wall and aids in water conductivity inplant vascular tissuecells.
Plant cell walls
Feature & Function.
How do the microfibrils form the wall ?
- Cellulose molecules are unbranched but are bonded to each other through hydrogen bonds.
2.This bonding between cellulose molecules forms a net-like arrangement called a microfibril.
- Microfibrils are in form hydrogen bonded between other microfibrils to form larger structures called macrofibrils.
- The net-like arrangement and the strength of the cellulose microfibrils are what make plant fibres so strong.
Plant Organelles
- Cell wall
- Chloroplast
- Middle lamella
- Amyloplasts
- Permanent Vacuole
- Tonoplast
- Plasmodesmata
- Pits
Why is the cell wall so strong. ?
- Due to the arrangement of cellulose micro fibrils in the cell wall
- Due to the secondary thickening of cell walls
Plant fibres are strong, in what ways do humans utilises this ?
We use them in :
- Ropes or fabrics like hemp.
Vacuole
- Stores cell sap. Surrounded by single membrane (tonoplast)
- Helps to keep plant cells turgid.
- Stores nutrients needed by plants as well as waste minerals.
Label and describe the function of this structure.
- It allows two neighbouring plant cells to transport substances between them and to communicate.
Label and describe the function of this structure.
- regions of a plant cell where the cell wall becomes very thin.
- pits allow neighbouring plant cells to exchange substances.
- arranged in pairs so that the pit of one plant cell is aligned with the pit of another plant cell.
Label and describe the function of this structure.
- storages starch granules
- Surrounded by a double membrane.
- Converts the starch back into glucose when the plant cell needs more glucose for respiration.
Relate the structure of cellulose to it’s function
- Composed of long beta-glucose chains that are held together by hydrogen bonds to form microfibrils.
Blurt everything you know and can remember about starch
- Amylose : 1,4 gb
- Amylopectin : 1,4 and 1,6 gb
- Insoluble so doesn’t affect osmosis.
Blurt everything you know about Xylem vessels
- Transport water and mineral ions from the roots to the rest of the plant. And to provide support.
- Made up of dead cells with open ends. The tubes are found together in bundles.
- No organelles or cytoplasm, which creates more space inside the vessel for transporting water.
- The cell walls contain pits which allow water and mineral ions to move into and out of the vessel
- Walls are thickened with lignin, which strengthens the xylem vessel and provides structure and support to the plant.
Blurt everything you know about **Phloem tissue **
- Phloem vessels are made up of two types of cell - sieve tube elements and companion cells.
- The function of phloem tissue is to transport organic solutes (mainly sugars like sucrose) from
where they’re made in the plant to where they’re needed. This is known as translocation. - Like xylem, phloem is formed from cells arranged in tubes. But unlike
xylem, it’s purely a transport tissue — it isn’t used for support as well.
Blurt everything you know about Sieve Tubes
- The sieve tube are living cells and are joined end-to-end to form sieve tubes.
- The ends of each cell consist of a ‘sieve plate’ which contains lots of holes to allow solutes to move from one cell to the next.
- Contain no organelles and very little cytoplasm to create more space for solutes to be transported.
- The absence of a nucleus and other organelles means that these cells cannot survive on their own, so each sieve tube element is associated with a companion cell, which contains a nucleus and is packed full of mitochondria.
- The sieve tube element and the companion cell are connected through plasmodesmata (channels in the cell wall) which allow the two cells to communicate.
Blurt everything you know about Sclerenchyma fibres
- found within vascular bundles and provide structural support to the stem.
- made up of bundles of long, dead cells.
- The cells have a hollow lumen and the cell walls are thickened with lignin.
- The cell walls also contain more cellulose than a typical plant cell which makes sclerenchyma fibres particularly strong.
This is a picture of a stem please name the structure within the stem.
Plant fibres
Name the different Ions and their Importance
Mineral ions are found in the soil and are absorbed by the plant through their roots.
- Nitrate ions : needed for the production of DNA, Proteins and chlorophyll.
- Calcium ions : Forms Calcium pectate for cell wall, used in plant growth.
- Magnesium : Production of chlorophyll, activation enzymes.
What is the importance of water in plants.
- Required for photosynthesis.
- Maintain rigidity of cells.
- Transport of substances.
- Thermoregulation (water evaporating from leaves helps to cool plants down)
- To maintain structural rigidity.
