BIOL10002 Lecture Notes - Lecture 3: Cytoplasmic Streaming, Vimentin, Microvillus
Lecture 3
Eukaryotic Cells
Eukaryotic Nucleus
- Surrounded by a double membrane or nuclear envelope
- Presence of nuclear pores (75nm in diameter)
- DNA in long, linear strands covered with histones = chromatin
- Different organisms have different numbers of chromosomes
- Nucleolus = subregion of nucleus where ribosomal genes are transcribed
- RNA transcribed from DNA leaves nucleus via pores and goes out into the cell to be translated
Pores
- Lined with proteins and attached to lamina (nuclear skeleton)
- Evenly spaced over nuclear envelope
- Traffic of proteins and RNAs in/out of nucleus
- Located at site where inner membrane curls around to become outer membrane
Note: Endoplasmic reticulum is continuous with nuclear envelope – extends throughout the cell.
Endoplasmic Reticulum
- Consists of membrane cisternae that ramify through the cytoplasm. The result is internal
compartments and channels
- The ER is a dynamic structure, ever changing in structure and functions
- with ribosomes = rough ER – neat, folded structure
- no ribosomes = smooth ER – tubular structure
Ribosomes dock on ER to…
The protein can then be transported to Golgi complex.
Intracellular membranes
1. Provide a surface for biochemical reactions.
2. To establish compartments to prevent mixing.
3. To provide for transport of materials within the cell, from the cell to its exterior, or from the cell to
an adjacent cell
Golgi Complex
- Consists of flattened stacks of cisternae called Golgi bodies
- Golgi bodies are functional extensions of the ER
- involved in collection, packaging, and distribution of molecules
synthesised elsewhere in the cell
- Almost all the polysaccharide in cells is manufactured within the
Golgi bodies
- The polysaccharide may be attached to either protein or lipid
molecules in the Golgi bodies
Note: Polysaccharides on proteins may be used to distinguish between cells that are self and non-self
The Cytoskeleton
- Allows eukaryotes to be much larger than prokaryotes
- Act as a form of scaffolding or as structural elements within the cytoplasm of cells
- Involved in certain cell movements
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Document Summary
Surrounded by a double membrane or nuclear envelope. Presence of nuclear pores (75nm in diameter) Dna in long, linear strands covered with histones = chromatin. Different organisms have different numbers of chromosomes. Nucleolus = subregion of nucleus where ribosomal genes are transcribed. Rna transcribed from dna leaves nucleus via pores and goes out into the cell to be translated. Lined with proteins and attached to lamina (nuclear skeleton) Traf c of proteins and rnas in/out of nucleus. Located at site where inner membrane curls around to become outer membrane. Note: endoplasmic reticulum is continuous with nuclear envelope extends throughout the cell. Consists of membrane cisternae that ramify through the cytoplasm. The er is a dynamic structure, ever changing in structure and functions. With ribosomes = rough er neat, folded structure. No ribosomes = smooth er tubular structure. The protein can then be transported to golgi complex.
