Protein Synthesis

How many nucleotides are needed to code for a protein with 325 amino acids?

• 975

• 325

• 108

• 1200

All organisms use the same genetic code, so it is possible to produce human proteins using another organism's protein synthesis machinery.

• true

• false

Tags

NGSS.HS-LS1-1

Which of the following statements regarding the structure and function of tRNA is FALSE?

• Although each tRNA consists of a relatively short, single RNA strand, this single strand can achieve a three-dimensional structure by folding back upon itself and forming covalent bonds between complementary bases.

• Each type of tRNA molecule translates a particular mRNA codon into a particular amino acid.

• Although there are 61 codons that code for amino acids, there are only 45 different tRNA molecules.

• The nucleotide sequence at both the amino acid attachment and the anticodon ends of each tRNA is instrumental in specifying which amino acid is attached to the tRNA by aminoacyl-tRNA synthetase.

Tags

NGSS.HS-LS1-1

Cells are able to distinguish proteins destined for secretion or for segregation to specific intracellular compartments from those that will remain in the cytoplasm because __________.

• there are two types of ribosomes: one group that synthesizes cytoplasmic proteins only, and another type that synthesizes secreted or compartment-specific proteins only

• proteins destined for secretion or for a specific compartment are all synthesized in the nucleus, whereas cytoplasmic proteins are all synthesized in the cytoplasm

• ribosomes contain two types of subunits

• some proteins, as they begin to be synthesized, contain a signal region that causes the ribosome with its growing polypeptide to attach to the ER and translocate the polypeptide into the lumen (space) of the ER

During translation, amino acid chain elongation occurs until __________.

• the ribosome encounters a "stop" codon

• the polypeptide is long enough

• no further amino acids are needed by the cell

• all tRNAs are empty

During translation in a eukaryotic cell __________.

• polypeptides are synthesized at ribosomes, according to instructions carried by mRNA

• ribosomes move into the nucleus

• ribosomes move out of the nucleus

• all of these

Which of the following summaries of protein synthesis is correct?

• The mRNA is made on a DNA template, and then amino-acid-bearing tRNA’s bind to it through codon-anticodon pairing.

• DNA transposons leave the nucleus, are transported to a ribosome, and catalyze the polymerization of amino acids in a protein.

• DNA strands separate in the nucleus to form mRNA. mRNA leaves the nucleus and is transcribed into tRNA on ribosomes.

• DNA exchanges its thymine units with uracil (U) in polymerase. This activates polymerase, and it starts joining amino acids together.

Tags

NGSS.HS-LS1-1

The codons AAA, CCC, GGG, and UUU specify the amino acids lysine, proline, glycine, and phenylalanine, respectively. What peptide sequence would be encoded by the sequence 5'-CCCAAATTTGGG-3', if present in the coding strand of the DNA?

• phe-gly-pro-lys

• gly-phe-lys-pro

• gly-phe-pro-lys

• pro-lys-phe-gly

Tags

NGSS.HS-LS1-1

The number of nucleotide bases "read" together on the mRNA to designate each amino acid is _____; this unit is called a(n) __________.

• three … codon

• two … dipeptide

• one … amino acid

• three … triose

When RNA is being made, the RNA base __________ always pairs with the base __________ in DNA.

• U:T

• U:A

• G:U

• T:U