Features of a plant and animal cell
Plants and animal cell features:
- They both have membrane bound organelles that include
- Ribosomes- Where translation of proteins takes place
- Mitochondria- Where aerobic repiration takes place to create energy
- Nucleus, nucleolus- Where translation and ribosome synthesis take place
- Golgi apparatus- Where modification of proteins take place
- Plama membrane- This is the edge of the cell and things in and out of the cell
- Rough endoplasmic rediculum- On it are lots of ribosomes, proteins are created here
- They have a cell wall for support and rigidity
- Chloroplasts for photosynethesis. These also contain DNA
- Vacuole that aids in the tranportation of water
Starch and cellulose
This is a polysaccharide of amylose and amylopectin which give it 1,4 and 1,6 bonds respectivley. Amylopectin makes it a branched chain so energy is quick release. Anylose makes it a compact chain so as much starch can fit in to one cell as possible.
Cellulose: This is made up of beta glucose, inverted every other molecule to create the gylcosidic bonds. This gives it only 1,4 bonds so it is a compact molecule. Lines of cellulose are put over each other to create microfibrils, hydrogen bonds and hemicellulose is then between the cellulose to add support.
- 1,4 bonds = compact molecule
- Strach 1,6 bonds, amylopectin and anylose
- Cellulose: Hydrogen bonds, hemicellulose, beta,
The cell wall is split in to two parts:
- Primary cell wall containing hemicellulose and cellulose
- Secondary cell wall containing hemicellulose and cellulose and ligin
These structures provide the cell with support and the lignin gives support and makes it water proof so no water escaoes from the cell.
This allows for the plasmodemata to form, a hole in the cell water which interconnects the plant cells.
The plant cells are held together by the middle lemella made of calcium pectin.
Structure of a plant cell
A cross section of a plant cell will show:
Different types of cells are found in these areas:
- The cortex contains parenchyma cells which deal with metabolic processes
- The Epidermis contain chloenchyma cells which help with support and strength. They have think primary cell walls
- The vascular bundles contain schloenchyma cells which are used for support, they contain lignin so are dead and are hollow tubes
- The xylem contain xylem vessels which are used for support and water transport. They contain ligin which makes it string and water proof. They have end plates and pits for water transport.
Water and ions
Water is important becuase:
- It tranports minerals up the plant
- It helps support the plant
- It helps with photosynthesis
There are four differernt ions that plants need:
- Nitrates: These help with making amino acids in the plant which allow the plant to grow
- Magnesium: These help the plant photosynthesis by making chlorphyll
- Calcium: This conbines with pectin to form calcium pectate which helps with support and permeability
- Phosphates: These help create ATP which the plant uses as energy
These ions enter the plant by active transport in to the roots which provide a huge surface area. At night the minerals help guttation. Where ions move in the water conc is lowered resulting in water moving in to the plant creating a force which makes water leave the leafs.
Transpiration and lateral movement
Transpiration is the upward movement of water in a plant.
- The process takes place in the xylem vessels and comes about due to cohesion and adhesion. Since the exlem vessels are hollow tubes water fills up in them.
- One evapourates the process of cohesion happens; molecules are joined by hydrogen bonds so as one evapouates it pulls up the next molecule
- This continues until all the water is gone. To make sure the water doesn't fall down the process of adhesion happens
- This is where the water molecules stick to the xylem vessels and dont fall down.
- The amount of water lost is regulated by the Guard cells
Lateral movement of water
- This happens using three pathways to reach the xylem: Vacuolar, symplast and apoplast
- Vacuolar: Water enters the cells and is transported through the vacuoles of each cell and the plasmodemata. It cuts the cell membrane
- Symplast: Water goes through the connected cytoplasm and plasmodesmata.
- Apoplast: Goes along cellulose in cell wall but hits the casparian strip enters symplast