Plant Cells Flashcards
What are the two fundamental differences in a plant cell compared to an animal cell?
1) The plant cell has a rigid cell wall
2) The plant cell contains chloroplasts
What is the function of a chloroplast?
It is the site of photosynthesis - energy from the sun is used to make storage molecules
What is the function of amyloplasts?
They are storage vacuoles in the cytoplasm that store starch
What is a tonoplast?
A vacuolar membrane that surrounds a large central vacuole
What is a Parenchyma?
A type of plant tissue found throughout the plant. They fill spaces between more specialised tissues and may themselves have certain specialised functions
Cellulose is a?
Pollysaccharide
What is the structural difference between α-glucose and β-glucose?
OH molecules are on opposite sides of the molecule in b-glucose
What is cellulose made up of?
B-glucose
What reaction occurs to join two b-glucose molecules together?
A condensation reaction
What type of bond forms?
A 1,4 glycosidic bond
What bonds form between cellulose chains?
Hydrogen bonds
Is cellulose a long/short, branched/unbranched molecule?
Long unbranched molecule
Is cellulose soluble or insoluble?
Insoluble
What are microfibrils?
Bundles of 60-70 cellulose molecules
When are microfibrils formed?
When hydrogen bonds form between the -OH groups in neighbouring cellulose chains
How are microfibrils arranged?
They are wound in a helical arrangement around the cell
How are the layers of microfibrils laid down?
At angles - forming a composite structure
How are microfibrils stuck together?
With a polysaccharide glue
What is a polysaccharide glue composed of?
Hemicelluloses and pectins
What does the polysaccharide glue bind to?
The surface of the cellulose and to each other, holding the cellulose microfibrils together
What are pectins also important for?
Holding or cementing cells together in the middle lamella
The arrangement of the cellulose microfibrils make the cellulose cell walls very?
Strong and flexible
What are plasmodesmata?
Narrow fluid filled channels that cross the cell walls making the cytoplasm of one cell continuous with the cytoplasm of the next
What two things are cell walls fully permeable to?
Water and solutes
