Chapter 15 genes and proteins

15.1 The Genetic Code

100

Protein sequences consist of ---- commonly occurring amino acids;

20

200

, the translation to protein is still systematic and ----

colinear,

300

Each amino acid is defined by a three-nucleotide sequence called the

triplet codon

400

The specification of a single amino acid by multiple similar codons is called

 "degeneracy."

500

The genetic code is nearly---

universal

15.2 Prokaryotic Transcription

100

Transcription always proceeds from the same DNA strand for each gene, which is called the

HINT strand

template strand.

200

The mRNA product is complementary to the template strand and is almost identical to the other DNA strand, called the

nontemplate strand

or coding strand

300

---- do not have membrane-enclosed nuclei.

Prokaryotes

400

Four of these subunits, denoted α, α, β, and β', comprise the polymerase----

core enzyme.

500

The polymerase comprised of all five subunits is called the -----

holoenzyme.

15.3 Eukaryotic Transcription

100

s. Eukaryotic mRNAs are usually ------ meaning that they specify a single protein.

monogenic,

200

The features of eukaryotic mRNA synthesis are markedly more complex than those of -----.

prokaryotes

300

. Transcription factors that bind to the promoter are called------- factors.

 basal transcription

400

Some eukaryotic promoters also have a conserved -----

CAAT box

500

----- transcription is a tightly regulated process that requires a variety of proteins to interact with each other and with the DNA strand.

Eukaryotic

15.4 RNA Processing in Eukaryotes

100

Eukaryotic mRNAs last for several hours, whereas the typical E. coli mRNA lasts no more than--------

five seconds

200

The cell performs an additional RNA processing step called ---------to remedy this

RNA editing

300

The tRNA folds to position the amino acid binding site at one end and the ---- at the other end

anticodon

400

. The anticodon is a ------- sequence in a tRNA that interacts with an mRNA codon through complementary base pairing.

three-nucleotide

500

Pre-tRNAs are transcribed and processed in the nucleus and then released into the ------ where they are linked to free amino acids for protein synthesis.

cytoplasm

15.5 Ribosomes and Protein Synthesis

100

The synthesis of proteins consumes more of a ----------- than any other metabolic process.

cell’s energy

200

. A ------- is a complex macromolecule composed of structural and catalytic rRNAs, and many distinct polypeptides

ribosome

300

. In -------, the nucleolus is completely specialized for the synthesis and assembly of rRNAs.

eukaryotes

400

. The complete mRNA/polyribosome structure is called a ------.

polysome

500

Through the process of tRNA “charging,” each tRNA molecule is linked to its correct amino acid by one of a group of enzymes called---------

aminoacyl tRNA synthetases.