The interrelationship between organelles involved in the production and secretion of proteins Flashcards
what is the first stage of making proteins
transcription
what is transcription
the copying of genetic information from DNA to RNA
how does transcription happen
DNA has the same genetic code for the protein that needs to be made, but proteins are made by the ribosomes (ribosomes are outside the nucleus in the cytoplasm). DNA is too large to leave the nucleus (double stranded) but RNA can leave the nucleus (single stranded)
where does transcription usually occur
where part of DNA temporarily unzips and is used as a template to assemble complementary nucleotides into messenger RNA
what happens after transcription
mRNA then goes through the pores of the nucleus with the DNA code and attaches to the ribosome
what is translation
decoding of mRNA into a protein.
what happens after translation
transfer RNA (tRNA) carries amino acids from the cytoplasm to the ribosome
where do amino acids come from
from the food we eat. proteins we eat are broken down into individual amino acids and rearranged into new proteins
what does tRNA consist of
a series of three adjacent bases in an mRNA molecules codes for a specific amino acid - called a codon.
each tRNA has 3 nucleotides that are complementary to the codon in mRNA.
each tRNA codes for a different amino acid
where do mRNA and tRNA meet
mRNA carrying the DNA instructions and tRNA carrying amino acids meet in the ribosomes. amino acids are joined together to make a protein
list the organelles involved in protein production
- nucleus and nucleolus
- ribosomes
- endoplasmic reticulum
- golgi apparatus
- cell surface membrane
what are the additional organelles involved in protein production
mitochondria and cytoskeleton
what do the nucleus and nucleolus do
nucleus produces mRNA which exits the nucleus through nuclear pores
what do the ribosomes do
mRNA attaches to ribosomes which can be free in the cytoplasm and attached to the rough endoplasmic reticulum. they are responsible for protein synthesis
what does the endoplasmic reticulum do
the rough ER is where ribosomes are attached to and where inital protein synthesis occurs
what does the golgi apparatus do
proteins are transported to the Golgi Apparatus in vesicles. the Golgi Apparatus modifies and packages proteins
what does the cell surface membrane do
vesicles containing proteins move to the cell surface membrane. exocytosis occurs to release the protein outside the cell
what do the mitochondria do
produce ATP which is used by contractile filaments within the cytoskeleton
what does the cytoskeleton do
made of contractile filaments and requires ATP to contract and move vesicles from Golgi to the cell membrane for exocytosis
outline the steps involved in protein synthesis and the modifying and packaging of proteins
1) mRNA copy of the instructions (gene) for insulin is made in the nucleus
2) mRNA leaves the nucleus through a nuclear pore
3) mRNA attaches to ER. ribosomes reads the instructions to assemble the protein (insulin)
4) Insulin molecules are ‘pinched off’ in vesicles and travel towards the Golgi Apparatus
5) Vesicle fuses with Golgi Apparatus
6) Golgi Apparatus processes and packages insulin molecules ready for release
7) packaged insulin molcuels are “pinched off” in vesicles from Golgi Apparatus and move towards the cell surface membrane
8) vesicle fuses with cell surface membrane
9) cell surface membrane opens to release insulin molcules outside
