The interrelationship between organelles involved in the production and secretion of proteins

Question 1

what is the first stage of making proteins

Answer 1

transcription

Question 2

what is transcription

Answer 2

the copying of genetic information from DNA to RNA

Question 3

how does transcription happen

Answer 3

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)

Question 4

where does transcription usually occur

Answer 4

where part of DNA temporarily unzips and is used as a template to assemble complementary nucleotides into messenger RNA

Question 5

what happens after transcription

Answer 5

mRNA then goes through the pores of the nucleus with the DNA code and attaches to the ribosome

Question 6

what is translation

Answer 6

decoding of mRNA into a protein.

Question 7

what happens after translation

Answer 7

transfer RNA (tRNA) carries amino acids from the cytoplasm to the ribosome

Question 8

where do amino acids come from

Answer 8

from the food we eat. proteins we eat are broken down into individual amino acids and rearranged into new proteins

Question 9

what does tRNA consist of

Answer 9

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

Question 10

where do mRNA and tRNA meet

Answer 10

mRNA carrying the DNA instructions and tRNA carrying amino acids meet in the ribosomes. amino acids are joined together to make a protein

Question 11

list the organelles involved in protein production

Answer 11

• nucleus and nucleolus
• ribosomes
• endoplasmic reticulum
• golgi apparatus
• cell surface membrane

Question 12

what are the additional organelles involved in protein production

Answer 12

mitochondria and cytoskeleton

Question 13

what do the nucleus and nucleolus do

Answer 13

nucleus produces mRNA which exits the nucleus through nuclear pores

Question 14

what do the ribosomes do

Answer 14

mRNA attaches to ribosomes which can be free in the cytoplasm and attached to the rough endoplasmic reticulum. they are responsible for protein synthesis

Question 15

what does the endoplasmic reticulum do

Answer 15

the rough ER is where ribosomes are attached to and where inital protein synthesis occurs

Question 16

what does the golgi apparatus do

Answer 16

proteins are transported to the Golgi Apparatus in vesicles. the Golgi Apparatus modifies and packages proteins

Question 17

what does the cell surface membrane do

Answer 17

vesicles containing proteins move to the cell surface membrane. exocytosis occurs to release the protein outside the cell

Question 18

what do the mitochondria do

Answer 18

produce ATP which is used by contractile filaments within the cytoskeleton

Question 19

what does the cytoskeleton do

Answer 19

made of contractile filaments and requires ATP to contract and move vesicles from Golgi to the cell membrane for exocytosis

Question 20

outline the steps involved in protein synthesis and the modifying and packaging of proteins

Answer 20

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