3.5.1-
DNA and RNA both consist of long chains of nucleotide units.
DNA has two strands forming a double helix RNA has one.
DNA has A,C,G,T. RNA has A,C,G,U.

3.5.2
The DNA helix unwinds, separating the two strands. RNA polymerase binds to the strand creating mRNA, which is a copied template of the strand. mRNA then leaves the strand.

3.5.3
The genetic code is three bases coding for one amino acid. A group of three bases is called a codon.

3.5.4
tRNA transfers amino acids from the cytoplasmic pool of amino acids to the ribosomes. The ribosomes add each amino acid brought to it by the tRNA to the growing end of a polypeptide chain.

3.5.5
Genes store the information needed to make a polypeptide in a coded form.
The sequence of bases in a gene codes for the sequence of amino acids in a polypeptide.



Transcription:
7.3.1.
Transcription is carried out in a 5'--> 3' direction because the strand being read is the leading strand, which goes from 5'-->3.The leading strand replicates faster than the laggin strand, which replicates in okazaki fragments.

7.3.2.
The sense strand of the DNA is the strand being copied during protein synthesis, the leading strand. That's why the sense strand is known as the template strand. Therefore, the antisense strand is the lagging strand, which isnt used during protein synthesis.

7.3.3.
Free nucleoside triphospates are broken down, and that energy is used to start protein synthesis, Transcription startw with rRNA polymeras undwiding DNA at the promoter region, which requires an initiator.

7.3.4.
Our DNa has introns, "Junk DNA", which is there just to occupy space. When mRNA replicates DNA, the iuntrons are replicated too. Before the mRNA leaves to start translation, The introns are removed ny enzymes.