Lecture Four - introduction into human cells Flashcards
Prokaryotic cells
single celled, no nucleus, example= eubacteria
eukaryotes
Animal and plant cells are examples
Single or multicellular, membrane bound, have a nucleus.
Structures found in most human cells
- Plasma membrane,
- RER
- Ribosomes
- SER
- Mitochondria
- Nucleus
- Secretory vesicles
- Lysosomes
- Centrioles
- Golgi apparatus
- Endosome
Difference between a cytoplasm and cytosol.
- Cytoplasm is everything within the cell except for the nucleus.
- Cytosol excludes ALL organelles within a cell.
Four classes of biological molecules found in cells
- Nucleic acids= DNA. RNA and nucleotides
- Lipids= fatty acids, triglycerides, Steroids
- Proteins= amino acids and polypeptides
- Carbs= monosaccharide, disaccharide. Polysaccharide
Nucleus structure
- Nuclear envelope= double membrane. Contains pores
- Nucleolus= site of ribosome synthesis.
- Chromatin (made up of DNA and protein). During cell division this condenses to form chromosomes
- largest organelle
Nucleus function
- Function= contains genetic information. Stores and transmits genetic information to the next generation of cells.
- Genetic information is coded in molecules of DNA.
- DNA is used to synthesize proteins.
Nuclear envelope structure
Double membrane containing pores
Nuclear envelope/ pores function
- Nuclear pores allow mRNA to leave the nucleus and enter the cytosol for translation.
- Proteins that modulate the expression of various genes in DNA move into the nucleus through pores.
Structure of RER
ribosomes bound to its cytosolic surface. Has a flattened sac appearance.
Role of the RER
Involved in processing and packaging proteins to send to the Golgi body.
Structure of SER
Smooth has no ribosomes on its surface. It has a branched tubular structure.
Role of the SER
Site of lipid molecule and steroid synthesis. It also plays a role in detoxification of certain hydrophobic molecules and stores and releases calcium ions involved in controlling various cell activities.
Role of ribosomes
Site of protein synthesis- involved in translation of mRNA into the primary structure of proteins- polypeptide chains.
Proteins are synthesized on free ribosomes and are released into the cytosol OR on ribosomes attached to the RER which then pass into the lumen of the RER.
Structure/positioning of ribosomes
- no membrane
- Made up of RNA and protein
- free floating or attached to surface of RER.