Unit 1 KA3 - Gene Expression
Gene expression involves the... of DNA Sequences
Translation and Transcription
Only a fraction of genes in a cell are...
expressed
Each nucleotide in an RNA molecule is composed of a...
Ribose sugar, a base, and a phosphate.
What pairs with adenine in RNA?
Uracil
A molecule of RNA is
Single Stranded
What does Messenger RNA (mRNA) carry a copy of?
The DNA code from the nucleus to the ribosome.
mRNA is transcribed from DNA in the...
Nucleus
What is mRNA translated into?
Proteins by ribosomes in fhe cytoplasm.
What is each triplet of bases on tbe mRNA molecule called?
Codon
What does a codon do?
Codes for a specfic amino acid.
Transfer RNA (tRNA) folds due to...
Complimentary base pairing
Each tRNA molecule carries its...
Specific amino acid to the ribosome
What does a tRNA molecule have?
An Anticodon (an exposed triplet of bases) at one end and an attachment site for a specifc amino acid at the other end
Ribosmal RNA (rRNA) and proteins...
Form the ribosome
Which RNA has a folded shape?
tRNA
What enzyme moves along DNA and unwinds the double helix?
RNA Polymerase
What happens to hydrogen bknds between base pairs?
They break.
What does RNA Polymerass do during transcription? (2)
Breaks the bonds
Synthesises a primary transcript of mRNA from RNA nucleotides by complementary base pairing.
What are Introns?
They are non-coding regions and are removed from the primary transcript
What are exons?
They are coding regions and are joined together to form the mature transcript.
What happens to the order lf the exons during splicing?
They remain unchanged
What does RNA splicing form?
a mature mRNA transcript
tRNA is involved jn the translation of...
mRNA into a polypeptide at a ribosome.
Translation begins...
at a Start codon and ends at a Stop Codon.
Anticodons bond to codons by...
Complementary base pairing, translating the genetic code into a sequence of amino acids.
What joins amino acids together?
Peptide bonds.
What happens to the tRNA as the polypeptide is formed?
tRNA leaves the ribosome.
Different proteins can be expressed from one gene, as a result of...
Alternative RNA splicing
Different mature mRNA transcripts are produced from the same primarh transcript depending on...
Which exons are retained
Amino acids are linked together by peptide bonds to form...
Polypeptides.
Polypeptide chains fold to form...
The 3D shape of a protein, held together by hydrogen binds and other interactions begweem individual amino acids
Proteins have a large variety of shapes which...
Determines their functions