2.1. Prokaryotic vs Eukaryotic Cells Flashcards
Eukaryote summary…
Are up to 10x bigger than prokaryotes.
Evidence great levels of compartmentalisation, a process that increases efficiency in subcellular processing.
Cell walls of plant cells contain peroxisomes, which contain the reducing enzyme catalase and small amounts of oxidase.
Furthermore, plant cells contain plasmodesmata: a narrow thread of cytoplasm that passes through cell walls of adjacent cells to aid communication.
Nucleus…
Contains the cell’s genetic material.
Replication of this DNA and transcription takes place in the nucleus.
There is a nucleolus, where production of ribosomal RNA takes place.
There is a double membrane around the nucleus to protect the DNA, with nuclear pores to allow exchange (each pore surrounded by 8 large protein granules).
RER…
Up to 10% of the interior volume of a cell.
Found very close to the nucleus.
Studded with ribosomes that are temporarily attached to its outer surface.
Segregates newly synthesised proteins away from the cytoplasm and transports them to other areas of the cell.
Proteins can be chemically modified by the RER, altering their function.
SER…
Contains no ribosomes on the outside.
More tubular than the RER.
Responsible for chemical modification of small molecules taken into the cell (including modification of drugs).
Site of hydrolysis of glycogen in animals.
Site for synthesis of lipids and steroids.
Ribosomes…
Found either:
1. Attached to the surface of the endoplasmic reticulum or free.
2. Inside mitochondria or chloroplasts.
In prokaryotic cells, they float freely in the cytoplasm.
The site of protein synthesis (translation).
Golgi apparatus…
Usually consists of flattened membranous sacs called cisternae.
Receives proteins from the RER and can modify, concentrate, package and sort them.
In plant cells, this is the site of synthesis of the polysaccharide cell wall.
The cis side is the receiving side and the trans side is the shipping side.
Lysosomes…
Vesicle containing digestive enzymes that come, in part, from the golgi.
Autophagy (the digestion of old cellular components) and regular breakdown of food and foreign material in the cell occurs here.
Mitochondria…
Have their own DNA, similar to bacterial cells.
Produces ATP through ATP synthesis.
650 mitochondrial proteins have been identified in human heart cells.
Plastids…
For example, chloroplasts.
Mostly found in plant cells and some protists.
Vacuoles…
Storage of water inside the cell (helps maintain the structure).
Key role in reproduction and digestion too.
