Cells - Protien Synthesis

Question 1

What is protein synthesis?

Answer 1

Proteins are created on biomes the production of proteins from the DNA code occurs in two main stages:
Transcription: where one gene on the DNA is copied into mRNA.
Translation: where the mRNA joins with the ribosome and corresponding tRNA molecules bring the specific amino acid the codon codes for.

Question 2

Where does transcription take place to begin with?

Answer 2

Inside of the nucleus

Question 3

What is the first step of transcription?

Answer 3

A complimentary mRNA copy of one gene on the DNA is created in the nucleus.

mRNA is much shorter than DNA so it is able to carry the genetic code to the ribosome in the cytoplasm to enable the protein to be made.

Question 4

What is the process of transcription in six steps?

Answer 4

1. The DNA helix unwinded to expose the bases to act as a template.
2. Only one chain of the DNA act as a template.
3. Like with DNA replication, this unwinding and unzipping is catalysed by DNA helicase.
4. DNA helicase breaks the hydrogen bonds between bases.
5. Free mRNA nucleotides in the nucleus align opposite exposed complementary DNA bases.
6. The enzyme RNA polymerase bond together the RNA nucleotides to create a new RNA polymer chain. One entire gene is copied.

Question 5

What happens once the DNA strand is copied?

Answer 5

mRNA is modified and then leaves the nucleus through the nuclear envelope pores.

Question 6

How does pre-mRNA become mRNA?

Answer 6

The introns are sliced out by a protein called spicesome this leaves just the Exxon and the coding regions.

Question 7

What is the stage of translation?

Answer 7

This is the stage in which the polypeptide chain is created using both the mRNA base sequence and the tRNA.

Question 8

What is the process of translation in six steps?

Answer 8

1. Once the modified mRNA has left the nucleus, it attaches to a ribosome in the cytoplasm.
2. The ribosome attaches at the start codon.
3. tRNA molecule with the complementary anticodon to the start code on aligned opposite the mRNA held in place by the ribosome.
4. The ribosome will move along the mRNA to enable another complementary tRNA to attach to the next codon on the mRNA.
5. The two amino acids that have been delivered by the tRNA molecule are joined together by a peptide bond. This is catalysed by an enzyme and requires ATP.
6. this continues until the bone reaches at the end of the mRNA molecule does not amino acid and therefore ribosome and translation ends.

Question 9

Once translation has ended, what happens

Answer 9

The polypeptide chain is now created and will enter the Golgi body for folding and modification.

Question 10

What is a codon? What is a start codon?

Answer 10

A sequence of three nucleotides which together form a unit of genetic code in a DNA or RNA molecule.

The first code on of messenger RNA transcript translated by a ribosome.