Cell organelles Flashcards
What is the role of the cytoskeleton?
- Holds organelles in place
- Controls cell movement
- Controls movement of organelles
What 3 components make up the cytoskeleton?
Microfilaments
Microtubules
Intermediate fibres
What are microfilaments formed from?
The protein actin
What is the role of microfilaments?
They are contractile fibres which are responsible for:
- cell contraction during cytokinesis
- cell movement
What is the role of microtubules?
- Used as a scaffold-like structure that determines the shape of the cell
- Act as tracks for the movement of organelles
What is the role of intermediate fibres?
- Give mechanical strength to cells
- Help maintain cell integrity
What are centrioles composed of?
Microtubules
What are centrioles responsible for?
The assembly and organisation of the spindle fibres during cell division
What are flagella and cilia?
Extensions that protrude from some cell types
What is the role of flagella?
They enable cells motility
What is the smooth endoplasmic reticulum responsible for?
Lipid and carbohydrate synthesis
Storage
What is the rough endoplasmic reticulum responsible for?
The synthesis and transport of proteins
Where do you find ribosomes?
Either free floating in the cytoplasm, or attached to endoplasmic reticulum (making it rough)
Are ribosomes surrounded by a membrane?
No
What are ribosomes the site of?
Protein synthesis
What is the role of Golgi apparatus?
Modifying proteins and packaging them into vesicles
What are the Golgi and endoplasmic reticulum both made up of?
Cisternae
Summarise the inter-relationship between organelles in protein production
1) Proteins are synthesised in the ribosomes on the rough endoplasmic reticulum
2) They then pass into the cisternae of the RER, and are packaged into transport vesicles
3) Vesicles containing the protein are moved towards the Golgi via the cytoskeleton
4) The vesicles fuse with the cis face of the Golgi and the proteins enter
5) The proteins are structurally modified before leaving the trans face of the Golgi in vesicles
6) These vesicles are either secretory vesicles, which carry proteins to be released by exocytosis, or lysosomes, which contain proteins for use in the cell
What are three structures that plant cells have that animal cells do not?
- Vacuoles (if they appear in animal cells they are small and transient)
- Chloroplasts
- Cell walls
What are three general roles of the cytoskeleton?
Providing mechanical strength to cells
Aiding transport within cells
Enabling cell movement
What is the structure of chloroplasts?
- Double membrane
- Fluid enclosed
- Internal network of membranes
Like mitochondria, what do chloroplasts contain?
Their own DNA and ribosomes
Which ribosomes are larger, eukaryotic or prokaryotic?
Eukaryotic ribosomes are 80S (bigger), whereas prokaryotic ribosomes are 70S (smaller)
What are plant cell walls made out of?
Cellulose
What are prokaryotic cell walls made out of?
Peptidoglycan
3 similarities between prokaryotic and eukaryotic cells
Both contain ribosomes
Both have a cytoskeleton
Both have a cell-surface membrane
3 differences between prokaryotic and eukaryotic cells
Prokaryotic do not have a nucleus
Prokaryotic have no membrane-bound organelles
Prokaryotic have a peptidoglycan cell wall
What are fungi cell walls made out of?
Chitin
