1.2 Proteins Flashcards
What is the proteome
The proteome is the entire set of proteins expressed by a genome.
The proteome is larger than?
The number of genes, particularly in eukaryotes, because more than one protein can be produced from a single gene as a result of alternative RNA splicing, in which introns are removed from RNA transcripts and exons are retained.
Not all genes are expressed as?
Proteins in a particular cell type.
Genes that do not code for proteins are called?
Non-coding genes, for example tRNA, rRNA and RNA molecules that control the expression of other genes.
The set of proteins expressed by a given cell type can be affected by?
Different conditions and various time differences
Some factors affecting the protein expressed by a given cell type is?
The metabolic activity of the cell, cellular stress, the response to signalling molecules, and diseased versus healthy cells.
What is the ratio of a eukaryotes cells surface area to volume ratio
small surface area to volume ratio because of their size.
Due to the small surface are to volume ratio eukaryotes plasma membrane has the inability to?
Carry out all the vital functions carried out by membranes.
Eukaryotes have what in place to increase the total area of membrane?
A system of internal membranes.
What is the Endoplasmic Reticulum (ER)?
Forms a network of membrane tubules continuous with the nuclear membrane.
What is the Golgi Apparatus?
A series of flattened membrane discs.
What are Lysosomes?
Membrane-bound organelles containing a variety of hydrolyses that digest proteins, lipids, nucleic acids and carbohydrates.
What are Vesicles?
Vesicles transport materials between membrane compartments.
The components of membranes, phospholipids and proteins are synthesised where?
Endoplasmic Reticulum
What are phospholipids?
Phospholipids are a type of lipid that forms the main component of a cell membrane.
What is Lipids inserted into and where are they synthesised?
Lipids are inserted into the membrane after being synthesised in the smooth endoplasmic reticulum (SER)
What is the difference between Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER)?
RER has ribosomes on it’s cytosolic dance, while smooth ER lacks ribosomes.
The synthesis of all proteins begins where?
Cytosolic Ribosomes
What type of protein synthesis is completed in cytosolic ribosomes and where does it remain?
Cytosolic proteins are started and completed in cytosolic ribosomes and remains in the cytosol.
Transmembrane proteins carry a signal sequence which?
Halts translation and directs the ribosome synthesising the protein to dock with the ER,
What is a Signal Sequence?
A signal sequence is a short stretch of Amino Acids at one end of a polypeptide that determines the eventual location of a protein in the cell.
What happens after the ribosome docks making RER?
Translation continues and protein is inserted into the membrane of the ER. Once the proteins are in the ER, they are transported by vesicles that bud off from the ER and fuse with the Golgi apparatus.
What happens to the proteins as they move through the Golgi apparatus?
Undergo post-transitional modification