7.3 RNA Flashcards
RNA stands for…
Ribonucleic acid
3 types of RNA:
mRNA- messenger RNA - codons (3 bases on each codon)
tRNA- transport/transfer RNA - anticodons
rRNA- ribosomal RNA - makes majority of ribosomes
Comparison of DNA to RNA:
DNA:
- double polynucleotide chain
- five carbon sugar is deoxyribose
- thymine present (pairs adenine)
- usually much longer than RNA
Comparison of RNA to DNA:
RNA:
- single polynucleotide chain
- five carbon sugar is ribose
- uracil present (pairs adenine)
- usually much shorter than DNA
Structure of RNA: nucleotides contain-
Adenine, guanine, cytosine and uracil (instead of thymine)
A gene is…
A section of DNA that codes for one protein
Role of RNA (stage 1)
Base sequence of the gene is copied into a molecule of RNA, it can pass through a pore in the nuclear membrane easily.
Role of RNA (stage 2)
RNA molecule carries the information in the DNA to the ribosome
Role of RNA (stage 3)
tRNA brings amino acids to the ribosome and they join up in the right order - the correct protein is made
It is difficult to see how proteins can result in an organism as complex as a human being, however enzymes are proteins and control…
Most of the metabolic reactions in the body
Transcription is…
DNA to mRNA
Translation is…
mRNa to protein
Anticodon is…
Particular amino acid attached to it
A sequence of three adjacent nucleotides located on one end of transfer RNA.
A primitive living thing would need to have some sort of…
- Metabolism, which involves enzymes - that are proteins
* It would also need to replicate itself so would need some sort of genetic material
Some scientists think that early in the development of life, RNA carried out both these functions…
Can act like an enzyme
Can also carry genetic information
It is thought DNA evolved later
