Cell Structure, Function and Transport Flashcards
Discovery of cells:
1665, Robert Jooke used an early compound microscope to look at a thin slice of cork, a plant material. Cork looked like thousands of tiny, empty chambers. Hooke called these chambers cell cells. Cells are the basic unit of life
The cell theory:
1) All living things are composed of one or more cells 2)Cells are the basic unit of life- all structured and their functions in living organisms 3) all cells arise from existing cells
Prokaryotes vs. Eukaryotes;
Prokaryotes- single celled organisms, do not contain a nucleus, do not contain other inter compartments, lived 3.5 billion years ago and were some of the first organisms on earth. Eukaryotes- first cells with internal compartments, arose 1,5 billion years ago, some are only made of one cell. Most single celled organisms have cilia, hair like projections that help an organism move or flagella.
Organelles and their functions
Cell membrane- regulates what enters and exits the cell, keeps cells nutrients inside the cell, transport proteins-help other molecules cross into the cell, cell signals receptors that bind to molecules that give cell signals. Lysosomes- small organelles that digest and break down unused molecules, viruses, bacteria, food, and waste (contain digestive enzymes).
Endosymbiotic Theory – chloroplasts and mitochondria
It explains the similarity of chloroplasts and mitochondria to free-living prokaryotes by suggesting that the organelles arose from prokaryotes through (endo)symbiosis.
Plant vs. Animal cells
Animals cells have a centriole and Lysosomes. Plant cells have a cell wall and Chloroplasts. They both have cell membrane, ribosomes, nucleus, endoplasmic reticulum, golgi apparatus, vacuoles, mitochondria, and a cytoskeleton.
Cell Membrane – structure and function;
This is the outer boundary that separates the inside of the cell cytoplasm, from the outside of the cell. The cell membrane also regulates what enters and exits the cell.
Passive Transport – 3 types.
No energy required. Diffusion- particles in a solution tend to move from an area where they are more concentrated to an area where they are less concentrated. Facilitated Diffusion- the movement of specific molecules across cell membranes through protein channels. Osmosis- Diffusion of water through a selectively permeable membrane.
Hypertonic, Hypotonic and Isotonic solutions
Hypotonic- the concentration of solute is higher inside the cell than outside Hypertonic- concentration of solute is higher outside the cell than inside. Isotonic- same concentration of solutes inside and outside the cell.
Active Transport – endocytosis and exocytosis:
Requires energy. Endocytosis- process of taking material into the cell by means of infolding, or pockets , of the cell membrane. Exocytosis- the membrane of the vacuole surrounding the material fuses with the cell membrane forcing content out of the cell.
