Prokaryotics and Eukaryotics
- Prokaryotic cells are single-celled organisms and are smaller and simplier than eukaryotic cells. An example of a prokaryotic cell is bacteria.
- Eukaryotic cells are complex and a bit more complicated than prokaryotic cells and examples of eukaryotic cells are animal and plant cells.
- Both types of cells contain organelles which are part of the cells and they all have different and specific functions.
Plant and Animal Cells are both EUKARYOTIC cells.
Animal cells contain:
- Cell membrane
- Rough endoplasmic reticulum
- Smooth endoplasmic reticulum mitochondrion
- Golgi apparatus
- Nuclear envelope
Plant cells contain all of the above, but ALSO contain; A cell wall with plasmodesmata, A vacoule and Chloroplasts.
An example of a prokaryotic cell is bacteria.
A prokaryotic bacterial cell contains:
- Cell wall
- Cell membrane
- Plasmids (small loops of DNA)
- Circular DNA
Differences between Prokaryotics and Eukaryotics
Prokaryotics and Eukaryotics have many differences
- Prokaryotic cells are a lot smaller than Eukaryotic cells.
- Prokaryotic cells don't have a nucleus (their DNA floats free in the cytoplasm). The DNA in a Prokaryotic cell whereas in a Eukaryotic it's linear.
- Prokaryotic cells have fewer organelles than Eukaryotic cells. For example, they don't have mitochondria.
- Prokaryotic cells have smaller ribosomes than Eukaryotic cells.
- Cell surface membrane - found on the surface of animal cells and inside plant cells and prokaryotic cells and made of protein and lipids - regulates the movement of substances into and out of the cell.
- Nucleus - large organelle surrounded by a nuclear envelope containing pores and nucleus contains chromatin and often the nucleolus - chromatin is made from DNA and helps to control the cells activities, the pores allow substances to move between the nucleus and cytoplasm and the nucleolus makes ribosomes.
- Lysosome - roung organelle surrounded by a membrane - contains digestive enzymes which can be used to digest invading cells or to break down worn out components.
- Ribosome - a very small organelle that floats free in the cytoplams or is attactched to roughER - it is the site where proteins are made.
- Endoplasmic reticulum (ER) - smoothER; system of membranes enclosing a fluid-filled space - synthesises and processes lipids, roughER; is similiar to smoothER but is covered in ribosomes - folds and processes proteins.
- Golgi Apparatus - a group of fluid-filled flattened sacs - processes and packages new lipids and proteins and makes new lysosomes.
- Mitochondrion - have a double membrane; inner one is folded to form cristae, inside is the matrix which contains enzymes involved in respiration - the site of aerobic respiration.
- Vesicle - small fluid-filled sac in cytoplasm surrounded by a membrane - transports substances in and out of the cell.
- Cell wall - rigid structure that surrounds plant cells.
- Chloroplast - small flattened structure found in plant cells and is surrounded by a double membrane - the site of photosynthesis.
- Centriole - small, hollow cylinders containing a ring of microtubules - involved in the seperation of chromosomes in cell division.
- Flagellum (flagella) - stick out from the cell surface and contain microtubules - microtubules contract to make the flagellum move.
- Proteins are made at the ribosomes
- Ribosomes on the roughER make proteins that are excreted or attached to the cell membrane. The free ribosomes in the cytoplasm make proteins that stay in the cytoplasm.
- New protiens produced at the roughER are folded and processed in the roughER and are then transported from the ER to the golgi apparatus in vesicles.
- At the golgi apparatus, the proteins may undergo further processing.
- The proteins enter more vesicles to be transported around the cell