Eukaryotic cells Flashcards
Eukaryote (definition)
An organism with membrane-bound organelles and DNA stored in a membrane-bound (true) nucleus.
1) Nucleus
(approx 5-20um)
> Controls the activities of the cell and contains most of the genetic information needed by the cell.
a. Nucleolus
> Site of RNA synthesis and ribosome formation.
b. Chromatin
> Mixture of DNA and Histones (proteins).
c. Nuclear Envelope
> Double membrane with nuclear pores to allow large molecules through (e.g. RNA).
d. Nucleoplasm
> Gel-like fibrous liquid enclosed by nuclear envelope.
2) Mitochondria
(approx 2-5um)
> Site of aerobic respiration, releases ATP for metabolic processes.
a. Double Membrane
> Inner and outer membrane, with inter membrane.
b. Cristae
> Fold extensions of the inner membrane
Contain protein pumps
Separate into compartments for different enzymes.
c. Matrix
> Space within where enzymes are and reactions take place.
d. DNA (mtDNA)
> Mitochondria’s own DNA
Unknown function
Mitochondria believed to have prior existed as a simple organism.
e. 70s Ribosomes
> Assumed to make specific proteins from genetic information stored in mtDNA.
3) Ribosomes
> Found in cytoplasm or rough ER
Two sub-units (70s, 80s)
Site of protein synthesis;
Acts as an assembly line for coded information from the nucleus to make proteins from amino acids.
4) Endoplasmic Reticulum (ER)
> A series of flattened membrane-bound sacs called Cisternae.
a. Rough ER
> Studded with ribosomes
Transports proteins made on the ribosomes for packaging or secretion.
