Eukaryotic Cells Flashcards
What is the cell wall in plants made of?
Insoluable cellulose
How does the cell wall become wood?
Impregnanted with lignin
What does pectin do in cell walls?
It holds the cell walls of neighbouring cells together and is formed as part of the middle lamella
What is the difference between a primary and secondary cell wall?
In a primary cell wall all the cells face the same way and it’s more flexiable. Secondary walls have more cellulose and are more ridged
What is the plasmodesmata?
Cytoplasmic bridges between cells to allow communication
What is the tonoplast?
A membrane that surrounds the vacuole and controlls what moves in and out
Why is the vacuole important in the cell’s water content?
The vacuole is filled with cell sap which means water moves into the cell by osmosis. This keeps the cell turgid once the turgor pressure stabalises and stops the plant from wilting
What are the similarities between chloroplasts and mitochondria?
Large Have seperate DNA Have an outer membrane Folded inner membrane Endo-symbyotic theory
What are the differences between chloroplasts and mitochondria?
Site of photosynthesis
Contain chlorophyll
How is magnification calculated?
Objective lense x magnification of eyepeice lense
What are the advantages of a light microscope?
Can use living tissue
Cheap
Portable
What are the disadvantages of a light microscope?
We have to prepare slides before we view them which may affect what we see
Limited resolution and magnification
How do you use an electron microscope?
Specimin must be dead and placed in a vacume
Electrons bounce off it to form an image
What are the benifits of using an electron microscope?
Huge magnification and resolution
What are the disadvantages of using an electron microscope?
Must be dead first
Hard to prepare slides
Expensive
Not portable
What is the function of a cell membrane?
They control what comes in and out of the cell and allows the fluids either side of the cell to have different compositions
What are vesicles?
Membrane sacks that hold the secretions made in cells
What two molocules make up cell membranes?
Lipids and proteins
What kind of lipids are in the membrane?
Phospholipids
What structure do the phospoholipids form in the membrane?
A bilayer
How does the proportion of phospholipids containing unsaturated fatty acids affect the fluidity of the membrane?
The more unsaturated fatty acids, the more fluid the membrane
What is the main function of membrane proteins?
To help substances move in and out of the cell.
In what ways can proteins help things move in and out of the cell?
Gated channels
Receptor molocules sensative to specific changes such as hormones
What is the protoplasm?
The cytoplasm and the nucleus combined
