Sem 2 - AOS 1 Flashcards
What are the 3 parts of Cell Theory?
- All organisms are composed of cells.
- The cell is the basic unit of structure and organisation in organisms.
- All cells come from pre-existing cells.
What does every cell have?
- Plasma Membrane
- Cytosol
- DNA
- Ribosomes
Prokaryotic Cells;
- No membrane bound organelles
- No nucleus
- Single Celled Organisms - Bacteria + Archaea
Eukaryotic Cells;
- Contain membrane bound organelles
- Have a nucleus
- DNA is located in the nucleus
- Animals, Plants, Fungi and Protists
Cells Changing Shape
Not all cells have a fixed shape;
- Cells with a cell wall can’t change shape
Surface Area to Volume Ratio
The higher the SA:V ratio, the greater efficiency of two-way exchange of materials across the plasma membrane.
Plasma Membrane
Function: boundary of a cell; maintains the internal environment of a cell by controlling the movement of substances into and out of the cell.
Found in both Prokaryotes and Eukaryotes.
Contains both lipid and protein
Have a phospholipid bilayer
Plasma membrane is said to be semipermeable or selectively permeable.
Cell Wall
Are only found in plant, fungi and bacterial cells.
• Are semi-rigid and are a protective barrier.
• Are located outside of the cell membrane.
• The composition of the cell wall varies in each type of organism:
Plants = cellulose (fiber)
Fungi = Chitin (Carbohydrate).
Bacteria = Complex polysaccharides
Nucleus
Control center of the cell.
• Contains all genetic information – DNA (Deoxyribonucleic Acid).
• Is surrounded by a double membrane known as the nuclear envelope.
• Most Eukaryotic cells have one nucleus (exceptions –
Some Liver cells have two. Red blood cells have none
except, when they are first made)
Mitochondria
Known as the “Powerhouse of the cell.” • Cellular respiration occurs in the mitochondria to release energy for the cell to use. • Is bound by a double membrane. • Has its own strand of DNA. • ATP: Adenosine triphosphate
Cytoplasm and Cytosol
Is a clear fluid within cell that contains all organelles excluding the nucleus.
• It moves materials throughout the cell.
• The cytosol is the fluid contents only of a eukaryotic cell.
Ribosomes
Is the site of protein synthesis.
• Are composed of protein and RNA.
• Are not enclosed in the membrane but found attached to rough ER or floating free in cytoplasm.
Endoplasmic Reticulum
Endoplasmic Reticulum (ER) is a series of membranous channels used for transport within cells.
• Rough ER is studded with ribosomes and makes proteins.
• Smooth ER: has no ribosomes and makes lipids.
• Is series of folded membranes.
Golgi Complex
- Stores, modifies and packages proteins for transport.
- Shifts proteins out of cells.
- Molecules are transported to and from the Golgi by means of vesicles.
- Cells that make saliva or mucus have many Golgi bodies.
Lysosomes
- Is the principal site of digestion within a cell
- Contain digestive enzymes that break down wastes.
- Are found in Golgi bodies.
- Help white blood cells to destroy bacteria.
- Apoptosis is programmed cell death.
