Genetics Chapter 9
Translation begins when the DNA in a chromosome unwinds and one strand is used as a template to make a pre-mRNA molecule.
False
Each amino acid is encoded by only one mRNA codon.
False
The set of proteins in a particular cell type is always equal to the number of genes in the genome.
False
mRNA is made up of introns that have been spliced together.
False
The process of post-transcriptional gene silencing triggered by micro-RNA molecules that stop translation is called ____.
RNA interference
The codon encoding the amino acid methionine functions as a start codon when it occurs at the beginning of a gene.
True
During translation, the rRNA in the large ribosomal subunit acts as an enzyme, linking amino acids together to form a polypeptide.
True
Prion diseases are always fatal and there is no treatment.
True
The most common mutation in cystic fibrosis is the deletion of a single amino acid which results in a misfolded protein.
True
Twenty different types of amino acids are used to make proteins.
True
Each amino acid has a different side chain, called a(n) ____.
R group
____ nucleotides form the code for one amino acid.
Three
An mRNA molecule has a cap attached to its 5' end and a poly-A tail attached to its 3' end.
True
One gene is able to encode information for different forms of a protein via ____.
alternative splicing
The three-dimensional shape of a protein is determined by the ____ and the results of chemical modifications and other processing events.
amino acid sequence
Proteins are composed of subunits called ____ linked together by chemical bonds.
amino acids
During the elongation step of translation, ____.
amino acids are added to a growing polypeptide chain
Peptide bonds form between ____.
an amino group and a carboxyl group
Amino acids are characterized by ____.
an amino group, a carboxyl group, and an R group
At one end of a tRNA molecule is a sequence of 3 nucleotides called an anticodon that ____.
binds to its complementary mRNA codon
Activated genes can be inactivated by reversing histone modification during a process called ____.
chromatin remodeling
Tetracyclines interfere with ____.
initiation of translation
The secondary structure of a protein forms ____.
pleated sheets or coils
Variant Creutzfeldt-Jakob disease is caused by errors in ____.
protein folding
Prions are created when normal proteins in the body ____.
refold into a different and infectious three-dimensional shape that kills cells in the brain and nervous system
Messenger RNA is a(n) ____ of the amino acid-coding nucleotide sequence of a gene.
single-stranded complementary copy
Most protein synthesis ____.
takes place on the surface of the rough endoplasmic reticulum
Codons are ____ that encode the information for a specific amino acid in a protein.
triplets of nucleotides in mRNA
The tertiary structure of a protein is ____.
formed by a protein region folding on itself
In pre-mRNA processing, ____.
introns are spliced out and the exons are combined in the mature mRNA
