Ch. 9 Quiz 1

What is meant by "gene expression"? (select all that apply)

• DNA is transcribed into mRNA

• mRNA is translated into a polypeptide

• A polypeptide is folded into a protein or protein subunit

• Different subunits originating from different gene sequences form a protein complex

AUG is called the "start codon." What happens here?

• DNA pol initiates replication

• RNA pol initiates transcription

• Spliceosome makes first mRNA cut

• Ribosome initiates translation

Codons are recognized and matched up to...

• tRNA anticodons

• tRNA codons

• Ribosomal anticodons

• Ribosomal codons

In a bacterium, gene expression involves (select all that apply)

• Transcription of DNA to mRNA

• Transcript modifications, such as addition of a 5' cap

• Movement of mRNA from the nucleus to the cytoplasm

• Translation by ribosomes in the cytosol

• Translation by ribosomes in the nucleus

Why does the Eukaryotic mRNA need a 5' cap and 3' tail? (select all that apply)

• Increases stability of the transcript in the cytosol, often by binding each other to form a circular mRNA

• Eukaryotic ribosomes first bind the transcript at the 5' cap

• The cap is translated into the first amino acid, Met, and the tail translates to the last, Lys

• The purpose is not currently well understood

How can the ~28,000 human genes lead to hundreds of thousands of human proteins?!

• Alternative splicing allows 1 gene to be expressed into multiple different proteins

• Alternative splicing can transform 1 gene into another gene

• Not all human proteins originate from our genes; some originate from the human diet

• Due to degeneracy of the genetic code, different amino acids can be added during the translation process, creating different proteins

What is meant by a "charged" tRNA?

• These tRNA molecules have their 3 phosphate groups still attached, meaning that they are a source of energy

• These tRNA molecules are covalently bonded to an amino acid

• These tRNA molecules are composed of positively charged amino acids

• These tRNA molecules have catalytic function, breaking ATP without the help of an enzyme

Because prokaryotes do not undergo post-transcriptional modifications, each mRNA transcript makes 1 type of polypeptide.

• True

• False