B2.2 & B2.3 Compartmentalisation and Specialisation Flashcards
What are the advantages of the separation of nucleus and cytoplasm?
Post-transcriptional modification can happen before the mRNA meets ribosomes in the cytoplasm. Not possible in prokaryotes.
Advantages of compartmentalization in the cytoplasm of cells
- Enzymes and substrates can be more concentrated
- Substances that can cause damage to the cell can be kept inside the membrane of an organelle.
- pH can be maintained at optimum level for a particular process.
- Organelles can be moved around with their content.
What are considered organelles?
YES: Nuclei, vesicles, ribosomes, and plasma membrane.
NO: cell wall, cytoskeleton, and cytoplasm.
What are the constraints with cell size?
- The surface area to volume ratio of a cell limits the size the cell can reach.
- Exchange of materials across a cell surface depends on its area.
- The need for exchange depends on cell volume.
- As the width of an object such as a cell increases, the SA increases, but at a much slower rate than the volume.
- When there is insufficient SA to support a cell’s increasing volume, the cell will either divide or die.
Outline the types of stem cells
- Totipotent: begins with these stem cells, have the ability of continued division & production of any tissue in the organism, may form a complete organism.
- Pluripotent: comes from totipotent & can mature into almost all different cell types existing in an organism, cannot differentiate into extra-embryonic cells.
- Multipotent: forms a limited number of cell types.
- Forms only one single cell type, present in adult organisms.
Give two examples of the location of stem cell niches in adult humans.
Bone marrow and hair follicles
What are the properties of stem cells?
They have the capacity to divide endlessly and differentiate along different pathways.
What is cell differentiation?
The development of unspecialised cells, after fertilisation, into specialised cells.
What is the importance of the stem cell niche?
Maintain the cells or promote proliferation and differentiation.
How is the size of male gametes (sperm cells) adapted to their function?
Long and narrow for streamlined swimming to the egg.
How is the size of red blood cells adapted to carry out their function?
Red blood cells are small to allow movement through narrow capillaries.
How is the size of muscle cells adapted for their function?
Muscle cells are larger than normal cells, and their longer length and diameter are designed to exert force during muscle contraction.
