Eukaryotic Cell Structure and Functions

Study Notes

Eukaryotic cells are more efficient than prokaryotic cells due to their discrete organelles, which are specialized to carry out specific tasks.
Eukaryotic cells are compartmentalized, allowing for separation of tasks and protection of sensitive components.

Separation of the nucleus and cytoplasm keeps DNA safe.
Enzymes and substrate can be more concentrated in a small area, increasing efficiency.
Harmful chemicals can be isolated, and pH levels can be maintained at different levels for different metabolic reactions.
Organelles can be moved, and larger membrane surface areas can be used for processes that take place across a membrane.
Example: Garlic cells contain alliin in vacuoles, which is converted to allicin (a toxic compound) when mixed with the enzyme alliinase, providing protection against herbivores.

All living things are made up of cells, but individual cells in different tissues can be quite different from one another.
The function of a cell determines its structure, and cells vary in size, shape, and organization.

Cell size is limited by energy and material requirements needed to stay alive.
Volume determines energy consumption, while surface area determines the rate of exchange with surroundings.
As a cell grows larger, its volume increases faster than its surface area, leading to a decrease in the SA:Volume Ratio.
If the metabolic rate exceeds the cell's ability to obtain material, the cell will die, making it beneficial for cells to be small.

Multicellular organisms are formed by repeated cell division and the grouping of similar cell types.
Being multicellular allows organisms to exceed body limits caused by the SA:Vol ratio, enabling growth without increasing cell size.
Cell specialization allows cells to become efficient in specific functions, interacting to achieve complex functions.

Every cell in a multicellular organism is a clone of an original parent cell (except gametes), with identical DNA.
Certain cells express specific genes, while others express other genes, leading to differentiation.

Stem cells are unspecialized cells with self-renewal and potency properties.
When a stem cell differentiates and becomes specialized, it cannot change again.
Stem cells are limited in availability.

There are three types of stem cells found at different stages of development:
- Totipotent: can form any cell type and divide into new organisms.
- Pluripotent: can form any cell type.
- Multipotent: can form a number of closely related cell types.