Intro to Cells Flashcards
Name 4 features that ALL cells posses
- Cell membrane
- DNA
- Cytoplasm
- Ribosomes
What are the differences between prokaryotic and eukaryotic cells?
- Prokaryotic cells: Small, relatively simple internal structures, no membrane-bound organelles, no true nucleus
- Eukaryotic cells: Larger, more complex, membrane-bound organelles, true nucleus, found in higher animals and plants
Where is the nucleolus located and what does it produce?
In the nucleus, produces ribosomes
Where are microtubules produced?
The centrosome - microtubule organising centre (MTOC)
Where does protein synthesis occur?
Ribosomes
What are the roles of the cytoskeleton?
- Helps to maintain cell shape
- Involved in cell motility
What is the plasma membrane?
- A semi-permeable barrier between the cytoplasm and external environment
- Retains most organically produced chemicals inside the cell
- Allows a few molecules across: diffusion, facilitated diffusion, osmosis, active transport
- Communication: receptors on cell surface
What is the fluid mosaic model?
- The cell membrane is a lipid bilayer: described as a fluid mosaic model
- Made up of phospholipids: polar (hydrophilic) heads and 2 non-polar (hydrophobic) tails
- Cholesterol embedded in the bilayer - provides membrane integrity (prevents lysis)
- Proteins: gateways that allow certain molecules into and out of the cell
What are some examples of cell membrane pathologies?
Haemoglobinopathies:
Sickle cell anaemia
Thalassaemia
Which type of cells contain a nucleus?
Eukaryotic cells
Describe the structure of the nuclear envelope
Double membrane, allows RNA and other chemicals to pass but NOT DNA
Where are ribosomes constructed?
In the nucleolus
How many chromosomes does a human have?
46
How is DNA organised within the nucleus of a eukaryotic cell?
It is condensed into chromatin
DNA wrapped around proteins called histones
Where does transcription of proteins occur?
In the nucleus
Where does translation of proteins occur?
Ribosomes
Describe the structure of ribosomes
- Present in eukaryotic and prokaryotic cells (larger in eukaryotes)
- Structure = a small and a larger subunit
- Role is to facilitate protein translation
Which organelle is described as a a protein factory of the cell?
Ribosomes
Give an example of a ribosomopathy
Treacher Collins syndrome (TCS) - results in abnormal craniofacial development
What is the endoplasmic reticulum?
- Mesh of interconnected cell membranes
- Involved in protein synthesis and transport
What is the role of the rough endoplasmic reticulum? (RER)
- Protein modification and production
- The rough endoplasmic reticulum connects to the nuclear envelope; mRNA is converted to peptides and passed on to the rough endoplasmic reticulum
Which disorders does endoplasmic reticulum dysfunction play a role in?
- Plays a role in numerous degenerative disorders: Alzheimer’s, Parkinson’s, Epilepsy
What is ER dysfunction assoiated with?
Ageing
What is the function of the smooth endoplasmic reticulum?
Manufacture of lipids
