Chapter 17 Flashcards
(32 cards)
what is gene expression?
gene expression is the process by which DNA directs protein synthesis: stages are transcription and translation
what is a metabolic pathway?
the way cells synthesize and degrade molecules in a series of steps
what is transcription?
transcription is the synthesis of RNA using information in DNA
what does transcription produce?
transcription produces mRNA (messenger RNA)
what is translation?
translation is the synthesis of a polypeptide using information in the RNA
what are the sites of translation?
ribosomes are the sites of translation
what is replication?
copying all of the DNA and all of the chromosomes to prepare for cell division
transcription turns - into -
transcription turns DNA to mRNA; it is the recipe for the protein
translation turns - into -
translation turns mRNA to proteins; it is the actual making of the protein
in eukaryotes, transcription is in? vs prokaryotes
in the nucleus because DNA is in the nucleus
- in prokaryotes, translation can begin before transcription
how many amino acids and how many nucleotide bases?
20 amino acids and 4 nucleotide bases
what are codons?
triplets of nucleotides; non-overlapping three-nucleotide words that are translated into a chain of amino acids to form a polypeptide; flow of information from gene to a protein is based on triplet code
where are codons located?
all are in the messenger RNA, mRNA
where are anticodons located?
all are in the tRNA
bases in dna vs rna
rna uses A&U G&C, dna uses A&T G&C
where does polypeptide synthesis start?
polypeptide synthesis always begins in cytosol at a free ribosome & can be moved to rough ER but never starts in rough ER
RNA polymerase does not need?
RNA polymerase does not need a primer
What is RNA synthesis?
RNA synthesis is catalyzed by RNA Polymerase, which pries DNA apart and joins together the RNA nucleotides, follows same base pairing rules but uses uracil
what is a promoter?
DNA sequence where RNA polymerase attaches
what is a terminator?
in bacteria, the sequence signaling the end of transcription is the terminator
what are the three stages of transcription?
initiation, elongation, termination
what are introns?
introns are intervening sequences that are noncoding and need to be cut out
what are exons?
exons are regions that are expressed and usually translated into amino acid sequences
what is RNA splicing?
removing introns and joining exons that creates an mRNA molecule with a continuous coding sequence
