NUCLEIC ACIDS Flashcards
1
Q
DNA organisation in eukarya
A
- DNA protein associated to stabilise it.
- DNA is linear
- mitochondria and plastids have separate genomes.
- non - chromosomal
- complex chromatin
- outer nucleus contains heterochromatin
- inner areas echromatin
2
Q
what is most protein content?
A
- histones
3
Q
what are nucleosomes?
A
DNA wound around hydrophobic histones.
4
Q
what are nucleosomes separated by?
A
- linker DNA
5
Q
what is a nucleosome?
A
- several nucleosomes and linker DNA
6
Q
what are the types of RNA?
A
- mRNA
- rRNA
- tRNA
- siRNA
7
Q
what is mRNA?
A
- messenger RNA
- used in transfer of information from DNA to ribosome for protein synthesis
8
Q
what is rRNA?
A
- ribosomal RNA
- forms part of structure of ribosome and catalyses formation of peptide bonds
9
Q
what is tRNA?
A
- transfer RNA
- traffics amino acids around cell to ribosome
10
Q
what is mRNA translation?
A
- happens on the ribosome
- start codons (met)
- stop codons (terminates translation)
11
Q
what is a gene?
A
- region of DNA that begins with start and stop
12
Q
what is an operon?
A
- region of DNA that is transcribed as a single mRNA strand.
13
Q
what is a gene cluster/ putative operon?
A
- if a group of genes are just close together
14
Q
features of ribosome?
A
- 60 % rRNA and 40 % protein.
- large and small subunits, each composed of many rRNA and protein pieces.
- bound to rough endoplasmic reticulum.
15
Q
structure of tRNA?
A
- r - shaped RNA molecules - one for each structural amino acid.
- has anti - codon loop
