central dogma and gene regulation quiz

how many different codons are there?

64

three nucleotides of mRNA that code for one amino acid

codon

A _______ gene is one that is expressed at all times, at relatively constant levels

constitutive

which of the following mutations always leads to a shift of the mRNAs reading frame?

deletion and insertion

which of the following best represents the central dogma of gene expression?

during transcription, DNA codes for mRNA, which codes for polypeptides during translation

transcriptionally active regions of chromatin in the nucleus are called

euchromatin

during eukaryotic RNA processing, the sequences that are spliced together and remain on the mature transcript are called _______

exons

in the eukaryotic cell, pre-mRNA is modified before leaving the nucleus. This modification _________

includes the removal of introns by alternative splicing involves adding a cap to the 5' end of the mRNA and tail to the 3' end is a point at which gene expression may be regulated

mutations can be ___________

neutral, beneficial, lethal, and heritable

in a eukaryote, DNA is transcribed in the __________

nucleus

transcription starts at the region of the gene called a

promoter

these molecules complex with proteins to form ribosomes

rRNA

DNA molecules contain sequences called ____________ that code for proteins

ribonucleic acids

sites for polypeptide assembly

ribosome

how many different amino acids make up a protein?

20

what is the start codon for RNA

AUG

which of the following adds RNA nucleotides, one at a time, to the growing mRNA strand during transcription?

RNA polymerase

these transcription factors bind to DNA and stimulate transcription

activators

alternative splicing ____________.

allows one gene to code for more than one polypeptide

in prokaryotes the unit of DNA that contains multiple structural genes under the control of a single promotor is called __________. The mRNA produced from this unit is referred to as ___________ mRNA.

an operon, a polycistronic

region of tRNA that is complementary to a mRNA codon

anticodon

which of the following is NOT a characteristic of RNA

bases are A, T, C, G

in the lac operon, the repressor protein binds to _______ to inhibit transcription

the operator

which process is responsible for the conversion of DNA information into messenger RNA?

transcription

__________ molecules carry amino acids to ribosomes

transfer RNA

occurs when stop codons are read

translation termination