Chapter 3- Cells Flashcards
What is a cell?
The smallest unit of life that can function independently.
What are the components of early cell theory?
1) All organisms are made of one or more cells.
2) The cell is the fundamental unit of life.
3) All cells come from preexisting cells.
What are the newer ideas of the modern cell theory?
1) All cells have the same basic chemical composition.
2) All cells use energy.
What does TEM stand for?
Transmission electron microscope- a very powerful tool for seeing internal cell structures.
What does SEM stand for?
Scanning electron microscope- a very powerful tool that reveals details on cell surfaces.
All cells have what?
Genetic material, ribosomes, cytoplasm, and a cell membrane.
What are Prokaryotes?
The most ancient forms of life. They are small, simple in structure, and lack a nucleus.
What are two different domains in prokaryotes?
Bacteria and Archaea.
What are Eukaryotes?
Evolved billions of years after prokaryotes, they are larger and more complex, and contain many internal parts such as the nucleus and membranous organelles.
What are some domains found within Eukaryotes?
Protists, fungi, plants, and animals.
What are bacteria?
They are prokaryotic, lack membrane-bounded organelles, and their ribosomes and DNA are freely in the cytoplasm.
What are animal cells?
Eukaryotic and they have many different membrane-bounded organelles.
What are plant cells?
They are also eukaryotic, but they also have chloroplasts, cell walls, and large central vacuole.
What is the main function of a cell membrane?
Forms a barrier between the cell and the outside world.
Where are phospholipids found?
They make up cell membranes.
What are phospholipids?
Amphipathic- meaning there are polar and non polar regions in the same molecule.
What is a hydrophilic head?
Polar bonds, which are attracted to water.
What is a hydrophobic tail?
Non polar bonds, which repel water.
When were cells discovered?
They were discovered after the microscope was invented in the mid 1800’s.
What does a bacteria contain inside of it?
They contain a cell wall, flagellum, ribosomes, cell membranes, and cytoplasm.
What are the three major components of Cytoskeletons?
Microfilaments, intermediate filaments, and microtubules.
What are microfilaments for?
They are needed for cell contraction and changes in cell shape.
What are intermediate filaments for?
They form a strong scaffold for mechanical strength.
What are microtubules for?
Microtubules act as trackways for moving organelles and vesicles.
Plant cells communicate through what?
Plasmodesmata
What are plasmodesmata?
Plasmodesmata are channels that pass through the plant cell wall.
What is the primary reasoning behind cells sticking together?
Cells stick together in multicellular organisms to keep in constant communication with each other.
How do animal cells communicate with each other?
They communicate through gap junctions.
What are gap junctions?
The proteins form tunnels through the membranes of two neighboring cells.
What are tight junctions in animal cells?
In tight junctions, proteins fuse the membranes of adjacent animal cells together.
What is the endomembrane system’s primarily function?
To move molecules around in a cell.
