Grade 12 IEB biology notes RNA, MEIOSIS

, Structure
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Molecule single stranded poly nucleotide
=


-




Single chain of nucleotides
-




RNA molecules shorter than DNA
.

RNA nucleotide consists of :



deoxyribose
1) Ribose sugar * is now
2) Phosphate group ribose

3) One of four bases uracil cytosine guanine adenine
:
,
. ,




* thymine changes
to uracil



-




Uracil similar to thymine & is still complementary to adenine


.


Uracil + cytosine =
pyrimidines ( single ringed
-




Guanine-1 adenine purines ( double ringed )
-


=
.




TYpeSOfRN
* 3 Types :




1) Messenger RNA ( mRNA)

carries info about amino acid sequence of a certain protein
from DNA in nucleus to ribosome

, 2) Ribosomal RNA ( rRNA)
forms ribosomes .
found in cytoplasm & are attached to endoplasmic
reticulum .




Site of protein synthesis transcription & translation




8) Transfer RNA ( tRNA)
Folded Picks
.
up amino acids in cytoplasm & brings to ribosome

then joined to form protein .




Locations
-




Nucleus of cell
-




Made by DNA
.




Also found in cytoplasm ( tRNA & mRNA)



proteinsynthesis.ie
Process
made -




proteins
-




Protein molecules =
long chains of amino acids bonded by peptide
bonds
.


20 amino acids make up proteins .




.