Chapter 17: Nucleic Acids and Protein Synthesis

Two Main Nucleic Acids

These are the repeating monomer units.

The nitrogen-containing bases in nucleic acids are derivatives of _____.

The purine bases with double rings are what?

The pyrimidine bases with double rings are what?

RNA contains the same pyrimidine and purine bases as DNA, except thymine (T) is replaced by _____.

The five-carbon sugar in RNA which gives the letter R in the abbreviation of RNA.

The five-carbon sugar in DNA, is similar to ribose except that there is no hydroxyl group.

A combination of sugar and a base, is produced when the nitrogen atom in a pyrimidine or a purine base forms an N-glycosidic bond to carbon 1 of a sugar, either ribose or deoxyribose.

These are nucleosides in which a phosphate group bonds to the —OH group on carbon 5 of ribose or deoxyribose.

These are polymers of many nucleotides in which the 3′-hydroxyl group of the sugar in one nucleotide bonds to the phosphate group on the 5′-carbon atom in the sugar of the next nucleotide.

The link between the sugars in adjacent nucleotides.

It is this sequence of bases that carries the genetic information from one cell to the next.

In 1953, James Watson and Francis Crick proposed that DNA was a ______ that consisted of two polynucleotide strands winding about each other like a spiral staircase.

In 1953, they proposed that DNA was a double helix that consisted of two polynucleotide strands winding about each other like a spiral staircase.

The pairs AT and GC; are the specific pairing of the bases occurs because adenine and thymine form only two hydrogen bonds, while cytosine and guanine form three hydrogen bonds.

This process begins when helicase catalyzes the unwinding of a portion of the double helix by breaking the hydrogen bonds between the complementary bases.

It makes up most of the nucleic acid found in the cell, is involved with transmitting the genetic information needed to operate the cell.

• The most abundant type of RNA is combined with proteins to form ribosomes.

• Ribosomes, which are the sites for protein synthesis, consist of two subunits: a large subunit and a small subunit.

It carries genetic information from the DNA, located in the nucleus of the cell, to the ribosomes located in the cytoplasm.

The smallest of the RNA molecules interprets the genetic information in mRNA and brings specific amino acids to the ribosome for protein synthesis.

A series of three bases that complements three bases on mRNA.

Genetic information for the synthesis of a protein is copied from a gene in DNA to make mRNA.

tRNA molecules convert the information in the mRNA into amino acids, which are placed in the proper sequence to synthesize a protein.

It consists of a series of three nucleotides in mRNA called codons that specify the amino acids and their sequence in the protein.

• Once the mRNA is synthesized, it migrates out of the nucleus into the cytoplasm to the ribosomes.

• In the translation process, tRNA molecules, amino acids, and enzymes convert the codons on mRNA to build a protein.

_____ of tRNA occurs when aminoacyl–tRNA synthetase forms an ester bond between the carboxylate group of its amino acid and the hydroxyl group on the acceptor stem.

The initial tRNA detaches from the ribosome, which shifts to the next available codon.

The first codon in mRNA is a ________, AUG, which forms hydrogen bonds with methionine–tRNA.

Another tRNA hydrogen bonds to the next codon, placing a second amino acid adjacent to ______.

A ____ bond forms between the C-terminal of methionine and the N-terminal of the second amino acid

During _______. the ribosome moves along the mRNA from codon to codon, so that the tRNAs can attach new amino acids to the growing protein chain.

Sometimes, ______ translates the same strand of mRNA to produce several copies of the protein at the same time.

____ are encountered which the termination of protein synthesis and the release of the protein chain from the ribosome.

A change in the nucleotide sequence of DNA.

If a mutation occurs in a ______, the altered DNA will be limited to that cell and its daughter cells.

If the mutation causes uncontrolled growth, _____ could result.

If a mutation occurs in a ____, then all the DNA produced in a new individual will contain the same genetic change.

When a mutation severely alters the function of structural proteins or enzymes, the new cells may not survive or the person may exhibit a _____.

The replacement of one base in the template strand of DNA with another.

This occurs if a substitution gives a codon for the same amino acid, and there is no change in the amino acid sequence in the protein.

A base is inserted into or deleted from the normal order of bases in the template strand of DNA.

It is the result of a defective enzyme caused by a mutation in its genetic code.

The transferase enzyme required for the metabolism of galactose-1-phosphate is absent, resulting in the accumulation of galactose-1-phosphate, which leads to cataracts and mental retardation.

• It is caused by a mutation in the gene for the protein that regulates the production of stomach fluids and mucus

• It is one of the most common inherited diseases in children, in which thick mucus secretions make breathing difficult and block pancreatic function.

It is the leading cause of mental retardation, occurring in about 1 of every 800 live births; the mother’s age strongly influences its occurrence.

It occurs when there is a mutation of a gene on chromosome 19, which produces high cholesterol levels that lead to early coronary heart disease in people 30 to 40 years old

• It is caused by a mutation in the X chromosome.

  • This muscle-destroying disease appears at about age 5, with death by age 20, and occurs in about 1 of 10 000 males.

• It affects the nervous system, leading to total physical impairment.

  • It is the result of a mutation in a gene on chromosome 4, which can now be mapped to test people in families with a history of HD.

• It is caused by a defective form of hemoglobin resulting from a mutation in a gene on chromosome 11.

  • It decreases the oxygen-carrying ability of red blood cells, which take on a sickled shape, causing anemia and plugged capillaries from red blood cell aggregation.

• It is the result of one or more defective blood-clotting factors that lead to poor coagulation, excessive bleeding, and internal hemorrhages.

• It is the result of defective hexosaminidase A, which causes an accumulation of gangliosides and leads to mental retardation, loss of motor control, and early death.

• These are small particles of 3 to 200 genes that cannot replicate without a host cell

• It does not have the necessary material such as nucleotides and enzymes to make proteins and grow.

• It begins when an enzyme in the protein coat of the virus makes a hole in the host cell, allowing the viral nucleic acids to enter and mix with the materials in the host cell.

It is a process that occurs once inside the host cell, it must first make viral DNA.

A virus that contains RNA as its genetic material.

An polymerase enzyme in a retrovirus that uses the viral RNA template to synthesize complementary strands of DNA.

A newly formed DNA that integrates with the DNA of the host cell.

Known to be the AIDS-causing agent.

A retrovirus that infects and destroys T4 lymphocyte cells, which are involved in the immune response.

Treatment of AIDS often combines reverse transcriptase inhibitors with protease inhibitors such as ____.

AIDS

human immunodeficiency virus