Protein biosythesis: Transcription and Translation Flashcards
What is a codon?
a row of three bases coding for an amino acid
What is a gene?
the lenght of DNA coding for one protein
What does mRNA stand for?
Messenger Ribonucleic Acid
What is mRNA?
a copy of DNA, as DNA can’t leave the nucleus
RNA is another type of nucleic acid
Which sugar does DNA/RNA contain?
DNA: deoxyribose
RNA: ribose
How many strands does RNA have compared to DNA
single-stranded (DNA double stranded)
Which base does DNA/RNA have?
RNA: uracil
DNA: thymine
How many amino acids are there?
20
How many amino acids are essential, and what does this term mean?
9, they have to be taken in through food
What is the first step of protein biosynthesis?
Transcription
What is Transcription?
the process of copying DNA
Describe Transcription
“DNA descripted in a message”
happens in nucleus
RNA-polymerase connects complimentary RNA nucleotides to DNA (hydrogen bonds) when hydrogen bonds break: single stranded mRNA
mRNA travels out of nucleus to ribosomes
What is protein synthesis?
the process of forming a protein using DNA
What does a ribosome?
helps to build protein
What does tRNA stand for?
transfer ribonucleic acid
Describe tRNA
carries an amino acid on it, amino acid= building block for a protein, “delivering an amino acid to ribosome docking bay” –> docks to mRNA using the help of complementary bases (three at once; codon)
Describe Translation
in the ribosome, tRNA that is carrying an amino acid docks onto mRNA using codons, tRNA leaves, amino acid stays, remaining is an amino acid chain making up a protein
What are introns?
segments of the DNA NOT coding for a protein - removed during RNA-splicing, make up 95% of genes (old name: junk-DnA)
What are exons?
nucleotide sequences with a coding function (average human gene: 8 exons)
What is RNA- splicing?
process during which introns are removed from mRNA, exons remain: mature mRNA
What is mature mRNA?
just exons, no introns
Why do we have introns?
only eukaryotes have introns
make new combination of exons easier; new combination of exons means new combination of genes–> evolution
introns help with gene expression: if they are removed artificially genes don’t work properly anymore
