Cell Organelles: Structure and Function Flashcards
What does the cytoplasm contain?
The cytosol (intracellular fluid) and the organelles
What are organelles?
Specialised structures which co-operate to maintain homeostasis
How much of a cell’s volume does cytosol make up?
55%
How much of cytosol is water?
Between 75 and 90%
What does cytosol contain?
Dissolved ions, glucose, amino acids, ATP, lipids and waste products
What is cytosol the site for?
A wide range of enzymatically-controlled reactions
What does the cytoskeleton consist of?
A network of protein filaments extending throughout the cytoplasm
What is the function of the cytoskeleton?
- Helps cells maintain their shape and internal organisation
- Provides mechanical support that enables cells to carry out essential functions like division and movement
What are the three main types of cytoskeleton?
Microfilaments, intermediate filaments and microtubules
Where are microfilaments found?
They surround the edge of the cell
What are microfilaments made up of?
Actin and myosin
What are the 3 functions of microfilaments?
- They help generate movement (contraction, locomotion and cell division)
- They provide mechanical support needed for cell strength and shape
- They create microvilli ( for example, in the small intestine)
What is 1 feature of intermediate filaments?
Very strong
Where are intermediate filaments found?
In parts of the cell subject to mechanical stress
What is the function of intermediate filaments?
They help stabilise the positions of organelles
What do intermediate filaments contain?
Proteins such as keratin, vimentin and lamin
Describe microtubules
Long, unbranched hollow tubules
What are microtubules made from?
Tubulin
Where do microtubules form?
In the centrosome, then radiate outwards
What are the functions of microtubules?
- Help with cell strength, shape and movement of organelles (such as vesicles and during cell division)
- Help provide structure to flagella (for example, spermatozoa)
Where is the centrosome found?
Near the nucleus
What are the 2 functions of the centrosome?
- Main microtubule organising centre and regulator of cell cycle progression
- Growth of the mitotic spindle during cell division
What do centrosomes consist of?
Two centrioles
What is a centriole?
Cylindrical structures composed of a circle of nine clusters of microtubule triplets
