CELLS I Flashcards
What is the Cell theory?
-Cells are the fundamental units of life
-All organisms are made up of cells
-All cells come from preexisting cells
-modern cells evolved from a common ancestor
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What is the Cell Membrane?
outer boundary of every cell; similar structure in all
cells—a phospholipid bilayer with embedded proteins.
What is Cytoplasm?
everything in the cell except the nucleus.
What is Cytosol?
fluid cytoplasm not contained inside another compartment.
What is the function of the Cell Membrane?
- Is a selectively permeable barrier
- Allows cells to maintain a constant internal environment
- Is important in communication and receiving signals
- Often has proteins for binding and adhering to adjacent cells
What is a Prokaryotic Cell?
-Mainly bacteria cells
Enclosed by a cell membrane.
* DNA located in a region called the nucleoid (instead of the nucleus)
* Cytoplasm: the rest of the cell contents
* Ribosomes: sites of protein synthesis
What are some traits of a Eukaryotic cell?
-Mainly Plant and animal Cells
-Eukaryotic cells are about 10 times larger than those of prokaryotes.
* Membrane-enclosed organelles carry out specific functions.
* Most eukaryotic cells have similar organelles.
What is the function of a Ribosome? What does it look like?
Ribosomes: Sites of protein synthesis.
* Have similar structure in prokaryotes and eukaryotes.
* Consist of ribosomal RNA (rRNA) and more than 50 different protein
molecules.
What is the function of a nucleus? What does it look like?
Nucleus—usually the largest organelle
* Contains most of the DNA
* Site of DNA replication
* Site where gene transcription is turned on or off
* Assembly of ribosomes begins in a region called the nucleolus
Name the different parts of the nucleus.
1) It is surrounded by the nuclear envelope
2) Nuclear pores in the envelope control the movement of molecules across the envelope.
3) The assembly of ribosomes begins in a region called the nucleolus
