Intro To Cells Flashcards
Describe prokaryotes.
Simple cell structure, no nucleus, two types which are bacteria and archea.
Describe eukaryotes.
Complex, DNA inside membrane-bound nucleus, contains organelles.
What are organelles?
Membrane-bound compartments with unique functions and structure. Variety of shapes and sizes. Eg. Skin cells and nerve cells.
What is cytosol?
Region in eukaryotic cells, outside organelles but inside plasma membrane. Cytoplasm includes everything in the plasma membrane- cytosol, endomembrane, semiautonomous organelles.
Describe bacteria cells.
Small between 1-10nm im diameter. Some causes diseases.
Inside plasma membrane- cytoplasm, nucleoid region (DNA location), ribosomes (makes protein),
Outside plasma membrane- cell wall (support and protect), glycocalyx (traps water, protect, help I have immune system), appendage (pilli attachment, flagella for movement).
Name 3 protein filaments in the cytoskeleton and briefly describe them.
- microtubles. Long hollow cylindrical structure, dynamic instability.
- intermediate filaments. Intermediate in size, form twisted rope like structure.
- actin filaments. AKA microfilaments, long thin fibres.
Describe nuclear envelope.
Double membrane structure enclosing nucleus. Outer membrane is continuous with ER membrane. Pores provide passageways. Material inside nucleus is not apart of endomembrane system.
Describe the endomembrane system.
Network of membranes enclosing nucleus, ER, Golgi apparatus, and lysosomes. Includes plasma membrane. May be directly connected to each other or pass material via vesicles.
Describe the nucleus.
Consist of the chromosomes (made of DNA and protein) and nuclear matrix (filamentous network which organises chromosomes).
Ribosome assembly happens here.
Describe the endoplasmic reticulum.
Network of membranes that form a flattened, fluid filled tubules/cisternae. Membrane enclosed compartment called ER lumen.
Name and describe two types of ER.
Rough ER- studded with ribosomes, involved in protein synthesis and sorting.
Smooth ER- less ribosomes, detoxification, carbohydrates metabolism, calcium balance, synthesis and modification of lipids.
Describe the Golgi apparatus.
Stake of flattened membrane bounded compartments. Vesicles transport materials between stacks. Functions- secretion, processing and protein sorting.
Describe the lysosomes.
Contains acid hydrorases that performs hydrolysis. Different types of acids hydrolysis to break down protein, carbs, Nucleocapsid acid, and lipids. (Autophagy)
What is autophagy and where does it happen?
Recycling worn out organelles via endocytosis. Lysosomes.
Describe peroxisomes.
Catalyse some reactions that break down molecules by removing hydrogen or adding oxygen. Hydrogen peroxide (H2O2) is a byproduct. Breaks down dangerous H2O2 into water and oxygen.
Describe the plasma membrane and its functions.
Wall between inside and outside of cell. Functions include transporting substances in and out of cell with selective permeability, cell signalling using receptors, and cell adhesion.
What are semiautonomous organelles.
Mitochondria and chloroplasts. Grow and divide to reproduce themselves. Not completely autonomous because they depend on the cell for synthesis of internal components.
Describe the mitochondria.
Has an inner (intermembrane) and outer membrane (mitochondrial matrix).
Purpose is to produce ATP energy. Involved in synthesis, modification, and breakdown of many cellular molecules.
Contain their own DNA and divid by binary fission.
What are membranes who has them?
Cell organelles have membranes and cells have plasma membranes. Thin usually 5-10nm thick. They regulate what enters and leaves the cell and its organelles.
Briefly explain the membrane structure and its components.
Phospholipid bilayer with globular proteins embedded (fluid mosaic model). Bilayer is amphipathic meaning they have both hydrophilic and hydrophobic regions.
4 components:
- PB (flexible matrix which acts as a barrier to permeability)
- trans membrane (integral protein)
- interior protein network (peripheral/intracellular membrane protein)
- cell surface markers (glycoproteins and glycolipids)
Name and explain two types of integral membrane proteins.
- Transmembrane proteins - more than one region is physically embedded into hydrophobic region of PB.
- Lipid anchor protein - can’t be released from membrane unless dissolved . Covalent attachment of lipid to AA side chain within a protein.
Describe peripheral/extrinsic membrane proteins.
They don’t associate with the inside of the cell. Bounded non-covalently H/ionic bonds to regions of the integral membrane. They are the proteins that stick up out of the surface.
