Histology Flashcards
What five features are common to all eukaryotic cells?
- Outer membrane
- Inner cytosol
- Cytoskeleton
- Membrane bound organelles
- Structures within the cytoplasm which may or may not be bound by a membrane and these are called inclusions
What is a eukaryotic?
A cell with a true nucleus
What is the inner cytosol of a eukaryotic cell?
A solution of proteins, electrolytes and carbohydrates. It has both fluid and gel-like properties.
What is the cytoskeleton of a cell?
It determines the shape and fluidity of the cell. It is made from thin and intermediate filaments and microtubules.
What are inclusions?
Other structures in the cytoplasm which may or may not be bound by a membrane
What does the plasmalemma seperate?
The cytoplasm from the outside environment
How is the plasmalemma composed?
It is a bimolecular layer of amphipathic phospholipid molecules with their hydrophilic heads at the outer and inner surfaces and their hydrophobic fatty acid chains facing towards the middle of the 2 layers
Name five types proteins in the plasmalemma
- Receptors
- Channels
- Transporters
- Enzymes
- Cell attachment proteins
What is the cell membrane highly permeable to?
Water, oxygen, small hydrophobic molecules
What is the cell membrane impermeable to?
Charged ions (Na+)
Where is choline present in a phospholipid?
In the polar hydrophillic region (head)
Where is phosphate in a phospholipid present?
Below the choline in the polar, hydrophillic region (head)
What are small, intracellular ‘organs’ with a specific function nad structural organisation?
Organelles
Name 6 organelles in the cytoplasm
- Mitochondria (energy production)
- Rough endoplasmic reticulum (protein synthesis)
- Smooth endoplasmic reticulum (cholesterol and lipid synthesis/detoxification)
- Golgi apparatus (modification and packaging of secretions)
- Lysosomes (hydolytic enzymes for intracellular digestion)
- Nucleus (contains genetic code)
What do mitochondria do?
Energy production
What does the rough endoplasmic reticulum do?
Protein synthesis
What does the smooth endoplasmic reticulum do?
Cholesterol and lipid synthesis/detoxification
What does the Golgi apparatus do?
Modification and packaging of secretions
What do lysosomes do?
Hydrolytic enzymes for intracellular digestion
What does the nucleus contain?
Genetic code
What can inclusions only be present as?
Transients
What do inclusions represent?
Components that have been synthesised by the cell itself (pigment, glycogen stores, lipid droplets, presecretion product) or taken up from the extracellular environment (endocytotic vesicle)
What are the three main classes of filaments in the cytoskeleton?
- Microfilaments
- Intermediate filaments
- Microtubules
What are microfilaments composed of?
Protein actin