Chapter 14

Question 0

Transcription

Answer 0

The first step of gene expression, in which a particular segment of DNA is copied into RNA by the enzyme RNA polymerase
-Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a complementary language

Question 1

Base Sequence

Answer 1

The order of nucleotide bases in a DNA molecule

Question 2

RNA

Answer 2

The nucleic acid that is used in key metabolic processes for all steps of protein synthesis in all living cells and carries the genetic information of many viruses

Question 3

mRNA

Answer 3

A large family of RNA molecules that convey genetic information from DNA to the ribosome, where they specify the amino acid sequence of the protein products of gene expression

Question 4

tRNA

Answer 4

• Transfer ribonucleic acid

- a type of RNA molecule that helps decode a messenger RNA (mRNA) sequence into a protein

Question 5

rRNA

Answer 5

A molecular component of a ribosome, the cells essential protein factory

• Ribosomal RNA
• rRNA does not make proteins, but makes polypeptides (assemblies of amino acids) that go to make up proteins

Question 6

Uracil

Answer 6

One of the four nucleobases in the nucleic acid of RNA

Question 7

RNA polymerase

Answer 7

An enzyme that produces primary transcript RNA

Question 8

Promoter

Answer 8

DNA sequences that define where transcription of a gene by RNA polymerase begins

Question 9

Pre-mRNA processing

Answer 9

• includes two different types of segments: exon and introns

- exons are segments that are retained in the final mRNA, where introns are removed in a process called splicing

Question 10

Exons

Answer 10

Any nucleotide sequence encoded by a gene that remains present within the final mature RNA product of that gene after introns have been removed by RNA splicing

Question 11

Codons

Answer 11

A sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis

Question 12

Genetic code

Answer 12

The set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins (amino acid sequences) by living cells

Question 13

Anticodon

Answer 13

A sequence of three bases that are complementary to a codon in the messenger RNA
-during translation, the bases of the anticodon form complementary base pairs with the bases of the codon by forming the appropriate hydrogen bonds

Question 14

Amino acids

Answer 14

The building blocks of all biological proteins

• amino acids link together by peptide bonds in a particular order as defined by genes
• genes are translated by RNA to amino acid chains; the length and order of the amino acid chain then dictates the three-dimensional structure of a polypeptide bond

Question 15

Peptide bond

Answer 15

• a chemical bond Formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule, releasing a molecule of water (h2o)
• this dehydration synthesis reaction (aka a condensation reaction), and usually occurs between amino acids

Question 16

Polypeptide

Answer 16

Chains of amino acids

-proteins are made up of one or more polypeptide molecules

Question 17

Initiation

Answer 17

The small subunit of the ribosome binding to the 5’ end of mRNA with the help of initiation factors (IF)

Question 18

Ribosome

Answer 18

A sphere-shaped structure within the cytoplasm of a cell that is composed of RNA and protein and is the site of protein synthesis

Question 19

Elongation

Answer 19

The stepwise addition of amino acids to the growing protein chain

Question 20

Termination

Answer 20

Stop of mRNA synthesis at the terminator site

Question 21

Translation

Answer 21

The process in which cellular ribosomes create proteins
-in translation, mRNA (produced by transcription from DNA) is decided by a ribosome to produce a specific amino acid chain (polypeptide)

Question 22

Gene

Answer 22

The molecular unit of heredity of a living organism
-it is used extensively by the scientific community as a name given to some stretches of deoxyribonucleic acids (DNA) and ribonucleic acids (RNA) that code for a polypeptide or for an RNA chain that has a function in the organism

Question 23

Alternative splicing

Answer 23

A regulated process during gene expression that results in a single gene coding for multiple proteins
-in this process, particular exons of a gene may be included within or excluded from the final, processed mRNA produced from that gene