dna genome and protein synthesis Flashcards
1
Q
what are introns and where are they placed
A
- introns are non-coding regions of DNA that do not code for an amino acid
-they are positioned in-between exons
2
Q
how is mRNA produced from an exposed template strand of DNA
A
RNA nucleotides form complementary base pairs
-phosphodiester bonds form
-done by RNA polymerase
3
Q
what is an exon
A
-base sequence coding for a polypeptide
4
Q
what are two differences between mRNA and tRNA
A
-mRNA is longer
-mRNA is linear and tRNA is clover leaf shaped
–mRNA contains more nucleotides than tRNA
-mRNA contains no paired bases/hydrogen bonds, tRNA does
5
Q
give ways the DNA of a chloroplast is different to DNA in nucleus
A
- DNA shorter in chloroplasts
- fewer genes
-DNA circular not linear
-not associated with histones
-introns absent in chloroplasts but present in nuclear DNA
5
Q
describe how transcription occurs in eukaryotes
A
-hydrogen bonds break
-only one DNA
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