Chapter 24 - Genes to Proteins

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Terms to Know in This Chapter:

universality of the genetic code

degeneration of the genetic code

adenine [ADD eh neen]

thymine [THIGH mean]

glycine [GLIE seen]

cytosine [CY toe seen]

uracil [YOUR ah sill]

mutagen (sing.) [MEW tah gin]

deletion [de LEE shun]

duplication [do plea KAY shun]

inversion [in VERS shun]

substitution [sub sti TOO shun]

insertion [in SUR shun]

albinism [AL beh niz um]

phenylalanine [FEE null AL ah neen]

tyrosine [TIE row seen]

dihydroxyphenylalanine (DOPA) [die high DROX ee FEE null AL ah neen]

tyrosinase [tie ROW seh nase]

alkaptonuria [al CAP toe NUR ee ah]

homogentisate oxidase [HOE moe gin TISS ate] [OX ee daze]

phenylketonuria [FEE null KEY toe NUR ee ah]

phenylpyruvic acid [FEE null pie RUE vick]

parahydroxylase [PAIR ah high DROX ee lase]

melanin [MEL ah nin]

m-RNA

t-RNA

r-RNA

codon

anticodon

regulatory genes

gene repression [re PRESS shun]

gene de-repression [DE re press shun]

co-repressor [CO re press or]

lactose [LACK tose]

glucose [GLUE cose]

galactose [gah LACK tose]

beta galactosidase [gah lack TOSE eh dase]

inducer [in DEW sir]

amino acid [ah MEAN oh]

histadine [HISS tah deen]

operon [OP er on]

regulator [REG you lay tore]

promoter [pro MOAT er]

RNA polymerase [poe LYM er aze]

messenger RNA

transcription [trans SCRIPT shun]

translation [trans LAY shun]

Genera You Need to Know:

People You Need to Know:

What You Need to Know:

You should be able to:

1. outline the contributions of Griffith, Avery, Delbruck, Hershey, Chase, Franklin, Watson and Crick,
2. describe Griffith's experiments and the conclusions derived from them,
3. explain how viruses (via bacteriophages) may infect cells and either become latent or undergo lysis,
4. explain how viruses can take over the genetic machinery of cells,
5. explain the sequence of events of transcription and translation of a gene into protein in a cell,
6. name the three types of RNA and explain the function of each,
7. explain what is meant by the universality of the genetic code,
8. explain what is meant by the degeneracy of the genetic code,
9. define the terms codon and anticodon, and,
10. explain the types of chromosomal and gene mutations.
11. explain how lactose is broken down into glucose and galactose,
12. describe the work of Francois Jacob and Jacque Monod,
13. describe a segment of a DNA molecule with the locations of the regulator, the promoter, the operator, and the structural genes,
14. define operon,
15. explain how an inducible operon works, and,
16. explain how a repressable operon works.

Exercises: Fill in the Blank.

1. RNA polymerase normally attaches to the region of a DNA molecule to read the gene and form messenger RNA.
2. In an inducible operon, RNA polymerase is often blocked by the presence of an produced by the .
3. In the lactose model of the inducible operon, serves to deactivate the repressor and turn the gene "on".
4. In the repressible operon model, serves as the co-repressor to turn the gene "off".
5. The repressor attaches to the region of the DNA molecule to turn the gene "off".
6. • The pathogenic form of Diplococcus pneumoniae is the (encapsulated, noncapsulated) strain.
   • When live mice have been injected with dead "S" bacteria and living "R" bacteria, the mouse (lives, dies).
   • The ability of one bacterium to take over the traits of another is called and is due to uptake of of one cell by another.
   • Delbruck and Hershey worked with a particular form of virus that infected bacterial cells. These viruses are called . When this virus injects its DNA into a host cell, the DNA may incorporate itself into the cell's DNA and either become (latent, lytic) and do nothing for a period of time, or become active and produce large numbers of viruses which cause the cell to undergo . (latency, lysis)
   • Hershey and Chase determined the material being transferred by the virus was DNA, and this was conclusive proof DNA serves as the information of living organisms.
   • The x-ray diffraction studies of DNA by allowed and to elucidate the structure of DNA.
   • The three types of RNA are , , and .
   • All RNA's are produced in the nucleus by the nucleolus. The form of RNA that transcribes the genetic information on a DNA molecule is . This RNA passes into the cytoplasm and attaches itself to a composed mostly of RNA. Floating free in the cytoplasm of the cell is another form of RNA that attaches itself to amino acids, also floating free in the cytoplasm, and brings the amino acids to the ribosome and messenger RNA. This form of RNA is RNA.
   • The messenger RNA has a sequence of three bases called the that attracts a sequence of three bases on the transfer RNA called the .
   • If a DNA sequence contains the bases ATTCGCCT, the messenger RNA sequence of bases would be , and the transfer RNA sequence of bases would be .
   • Most living organisms have the same genetic code. For this reason, we say the genetic code is .
   • The base sequence UCU, UCC, UCA, and UCG all stipulate the amino acid serine. Because the same amino acid can be coded for by more than one codon, we say the genetic code is .
   • There are two types of genetic mutations. They are
     a. , and
     b. .
   • If a normal chromosome segment reads a-b-c-d-e and a mutant chromosome segment reads a-b-c-c-d-e, then it would be an example of a(n) .
   • If a purine is replaced by a pyrimidine, the gene mutation is said to be a .

   Exercises. Multiple Choice. Select the best answer.

7. Lactose serves as a(n):

   (1) inducer.
   

   (2) repressor.

   (3) co-repressor.

   (4) promoter.

   (5) operator.

    

8. Tryptophan serves as a(n):

   (1) inducer.
   

   (2) repressor.

   (3) co-repressor.

   (4) promoter.

   (5) operator.

   
   

9. To what does RNA normally attach to eventually form m-RNA?

   (1) inducer
   

   (2) repressor
   

   (3) co-repressor.
   

   (4) promoter
   

   (5) operator

10. An operon is composed of:

    (1) the promoter, the operator, and any structural genes.
    

    (2) the regulator, the operator, and the promoter.
    

    (3) the repressor, the regulator, and the co-repressor.
    

    (4) the co-repressor., the repressor, and the regulator.
    

    (5) none of these.

11. Beta galactosidase is:

    (1) an enzyme that forms lactose from glucose and galactose.
    

    (2) produced in large quantities when no lactose is present.
    

    (3) inhibited when no lactose is present.
    

    (4) both 1 and 3.
    

    (5) both 2 and 3.

12. Who discovered the molecular structure of the DNA molecule?

    (1) Griffith and Avery
    

    (2) Delbruck and Hershey
    

    (3) Hershey and Chase
    

    (4) Franklin
    

    (5) Watson and Crick
    
    

13. If a bacteriophage injects its genetic material into a virus:

    (1) the material must be DNA.
    

    (2) the virus will undergo lysis.
    

    (3) the virus may become latent.
    

    (4) both 1 and 2 are correct.
    

    (5) both 1 and 3 are correct.
    
    

14. This type of RNA attaches to amino acids in the cytoplasm.

    (1) messenger RNA
    

    (2) transfer RNA
    

    (3) ribosomal RNA
    

    (4) polysomal RNA
    

    (5) nucleolar RNA

15. If the anticodon of t-RNA reads UCC, then the codon of DNA should read:

    (1) AGG.
    

    (2) UGG.
    

    (3) UCC.
    

    (4) ACC.
    

    (5) TCC.

16. If a segment of DNA is supposed to read CCGGCA but actually reads CCCA, then a:

    (1) frame shift called a deletion of a gene has occurred.
    

    (2) transversion gene mutation has occurred.
    

    (3) deletion of a chromosome segment has occurred.
    

    (4) substitution has occurred.
    

    (5) pyrimidine has been substituted for a purine.