Key Area 3: Gene Expression Flashcards
What are genes?
DNA sequences that code for particular proteins
What determines a cell’s phenotype?
The proteins which are synthesised when the genes are expressed.
What is translation?
Amino acids come together at the ribosome where they form a polypeptide chain.
What types of RNA are involved in transcription and translation?
mRNA, tRNA and rRNA
What is the transcription and translation of DNA sequences involved in?
Gene expression
How many strands are in RNA?
One.
What is RNA made from?
Nucleotides
What are the bases in RNA?
Adenine, Uracil, Cytosine, and Guanine.
What is mRNA?
Messenger RNA copies the code from the DNA and carries it to the ribosomes where they are joined together.
What is tRNA?
Transfer RNA is found in the cytoplasm and become attached to specific amino acids, bringing them to the ribosomes where they are joined together.
What is rRNA
Ribosomal RNA forms a complex with protein molecules to make the ribosome.
What is transcription?
The process which the DNA is used to produce an RNA moleule called a primary transcript.
What are introns and exons?
Human genes that have been divided into coding and non-coding elements. Introns are non coding and exons are coding.
Are introns or exons more useful?
exons
Why are exons more useful?
They are coding, so they carry the information needed for protein synthesis.
What is the first stage of transcription?
RNA polymerase moves along the DNA, unwinding the double helix
What is the second stage of transcription?
Hydrogen bonds between bases break, separating the two DNA strands.
What is the third stage of transcription?
Free RNA nucleotides bond with the complementary base pairs on the DNA
What is the fourth stage of transcription?
Hydrogen bonds form between complementary bases
What is the fifth stage of transcription?
Strong bonds form between the phosphate of one nucleotide and the ribose sugar of the adjacent nucleotides.
What is RNA polymerase?
An enzyme that moves along DNA unwinding the double helix and breaks the hydrogen bonds between bases.
What enzyme synthesises a primary mRNA transcript from RNA nucleotides?
RNA polymerase
What does non-coding mean?
A section of transcribed DNA which does not contain the information required to produce a protein