8.3-STRUCTURE OF RIBONUCLEIC ACID Flashcards
What does the sequence of nucleotide bases in DNA determine?
sequence of amino acids in proteins of organism
What is DNA largely confined to in eukaryotic cells?
largely confined to nucleus
Where does the synthesis of proteins happen in eukaryotic cells?
in cytoplasm
How is the coded information on the DNA in the nucleus transferred to the cytoplasm where its; translated into proteins?
sections of DNA code transcribed onto single-stranded molecule called ribonucleic acid (RNA)
What is messenger RNA/mRNA?
RNA that transfers DNA code from nucleus to cytoplasm acts as messenger
What is mRNA small enough to do?
small enough to leave nucleus through nuclear pores + enter cytoplasm, where coded info it contains used to determine sequence of amino acids in proteins which are synthesised there
What does the term codon refer to?
sequence of three bases on mRNA that codes for single amino acid
What is the genome?
complete set of genes in cell, including those in mitochondria and/or chloroplasts
What is the proteome?
full range of proteins produced by genome
What is the proteome sometimes called?
complete proteome
What does the term proteome refer to in complete proteome?
proteins produced by given type of cell under certain set of conditions
What is ribonucleic acid (RNA) usually made up of? (hint- nucleotide)
single nucleotide chain
What is ribonucleic acid (RNA)?
polymer made up of repeating mononucleotide sub-units
What is each RNA nucleotide made up of? (3)
pentose sugar ribose
one of the organic bases adenine (A), guanine (G), cytosine (C) + uracil (U)
phosphate group
What are the two types of RNA that are important in protein synthesis?
messenger RNA (mRNA) transfer RNA (tRNA)
What does mRNA consist of?
thousands of mononucleotides
How is mRNA arranges?
mRNA is a long strand that’s arranged in a single helix
What is the base sequence of mRNA determined by?
sequence of bases on length of DNA in process called transcription
What happens once mRNA forms?
mRNA leaves nucleus via pores in nuclear envelope + enters cytoplasm, where it associates with ribosomes
What does mRNA act as in the cytoplasm?
acts as template for protein synthesis
How is mRNA’s structure suited for its function?
as it possesses information in form of codons (three bases that are complementary to triplet in DNA)
What does the sequence of codons that the mRNA possesses determine?
amino acid sequence of specific polypeptide that will be made
What is the size of the transfer RNA (tRNA) molecule?
relatively small molecule
How many nucleotides make up the tRNA?
tRNA made up of around 80 nucleotides
What is the shape of the tRNA like?
single-stranded chain folded into clover-leaf shape, with one end of chain extending beyond the other
What does the end of the tRNA chain that extends beyond the other do?
this is part of tRNA molecule to which an amino acid can easily attach
What is at the opposite end of the ends of the tRNA chain?
sequence of three other organic bases, known as anticodon
What does the genetic code being degenerate say about the number of tRNA molecules?
must be as many tRNA molecules as there are coding triplets
What is each tRNA specific to?
each tRNA specific to one amino acid
What is each anticodon of tRNA specific to?
anticodon that’s specific to amino acid that tRNA is specific to
In RNA, what is the base thymine always replaced by?
similar base called uracil
How can RNA join with DNA and other RNA molecules?
by complementary base pairing
What is the complementary base pairings that RNA forms?
guanine with cytosine
adenine with uracil
What does an anticodon pair with during protein synthesis?
anticodon pairs with three complementary organic bases that make up codon on mRNA
What is the tRNA structure, with its end chain for attaching amino acids + its anticodon for complementary base pairing with codon of mRNA structurally suited for?
structurally suited to its role of lining up amino acids on mRNA template during protein synthesis
