OBJECTIVE SHEET NUCLEIC ACIDS AND PROTEIN SYNTHESIS
OBJECTIVE SHEETNUCLEIC ACIDS AND PROTEIN SYNTHESIS1. Name the four bases in DNA and describe the structure of DNA.2. Describe the steps involved in DNA replication. Include in your discussionhelicase, DNA polymerase, complementary base-pairs, anti-parallel,semi-conservative replication.3. Describe three uses for recombinant DNA (rDNA). List the dangers with theuse of this technology.4. Compare and contrast DNA and mRNA in regards to structure, function, andlocation in the cell.5. Outline the basic steps of protein synthesis. Identify the role of DNA, mRNA,tRNA and ribosomes in the processes of transcription and translation.Include in your discussion transcriptase, tRNA, codon, anti-codon,polypeptide.6. Determine the sequence of amino acids coded for by a specific DNA sequencegiven a table of mRNA codons or tRNA anticodons.7. Give examples of environmental mutagens that can cause mutation inhumans.8. Use examples to explain how mutations in DNA affect protein synthesis andmay lead to genetic disorders.9. Distinguish between chromosomal mutations and gene (point) mutations.10. Explain sex-linked diseases and the problems with phenotypic cures.1
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KaryotypesA picture of a chromosome will reveal distinctbands at various locations. These bands helpbiologists identify locations of specific genescalled “loci”.The banding pattern and size of thechromosome helps biologists determine whichof the 23 pairs of chromosomes they arelooking at.Arranging the chromosomes in order is calleda karyotype. Karyotypes can reveal manygenetic properties of an individual.3
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Reading AssignmentNucleic AcidsAnswer on a separate sheet of paper.1. Read pages 501 to 505. Pay close attention to any diagrams.2. State Chargaff’s rule.3. What contribution did Rosalind Franklin make?4. Who finally worked out the structure of DNA?5. What does 5 (5 prime) and 3 (3 prime) refer to?6. Draw a section of a DNA molecule that contains 4 different bases. Label thefollowing on your diagram: 5 - 3 and the 3 - 5 direction of the two strandsof DNA. Label the hydrogen bonds, purine bases, pyrimidine bases,deoxyribose, phosphate group.7. What is meant by anti-parallel?8. What does it mean when biologists say that during DNA replication, there is“semi-conservative replication”.Fill in the following blanks on this page:9. opens the DNA molecule by breakingbonds between the bases. This separates the DNA intoComplementary then occurs addingnew to the exposed ones by bonds. Thebase Thymine always bonds with and guanine alwaysbonds to . The enzymeis responsible for adding new nucleotides as well as ato ensure that there are no mistakes or made.5
10. If normal DNA containing non-radioactive N14 was placed into a solutionwith radioactive N15 and allowed to divide once. Then the N15 is removed andreplaced with N14 and allowed to divide one more time.a) How many DNA helixes are present?How many daughter cells will form?b) How many of the new DNA strands will be radioactive?c) How many of the new cells will be radioactive?d) When does DNA replication occur?6
Nucleic Acid ExerciseReplication, Transcription, TranslationDNA makes up the chromosomes of all cells. It contains the genetic informationthat enables a cell to carry on its life activities as well as to reproduce. RNA issmaller copy of a single section of DNA that carries DNA’s message out to thecytoplasm. Your group will need to follow the instructions in each of the threeparts of this exercise very carefully. Start by reading about the DNA molecule on page 504.*A. The Composition of DNAIn humans, DNA is a large molecule made up of about 6 billion smaller moleculescalled nucleotides. Each nucleotide is composed of three parts: a base (eitherguanine, cytosine, thymine, or adenine), a phosphate group, and a sugar calleddeoxyribose. You are going to build a small section of DNA using paper models.From the envelopes provided, go and get the following paper nucleotides:8 cytosine, 8 guanine, 4 thymine, and 4 adenine. Clear off your table and arrangethe nucleotides below vertically on your desk by linking them together. These willrepresent the “left side” of the DNA ineA1. Name the 2 molecules that alternate to form the outside “rail”A2. Name the molecule to which each base is attached.A3. Name the molecules that form the “half-rungs of the ladder”.Now use some of the extra molecules that you have to match the left side of theDNA on your desk. You will form a full ladder with 6 pairs of nucleotides. Fromnow on, you can use “A” to represent adenine, “C” for cytosine, etc.A4. Name the base pairings in your model.A5. If the left side of DNA is A T T C G G C T, what will the right side be?A6. What do you notice about the deoxyribose molecules when you compare theleft side to the right side? Start by reading pg. 506 *B. DNA ReplicationYou should remember a little about mitosis from grade 11. In mitosis, the parentcell divides to form 2 identical daughter cells. The doubling of the DNA occursduring prophase. This doubling of DNA is called DNA Replication. You are goingto use your paper model of DNA to see how this occurs in the nucleus of cells.Split your DNA molecule from part A down the middle into a left and right side.Add new complementary nucleotides to each side.7
B1. How many DNA “ladders” do you have now?B2. How do these ladders compare to each other?B3. How do these ladders compare to the original DNA ladder?B4. How does base pairing ensure that the DNA is copied correctly?B5. What would happen to the cell once it has 2 copies of DNA in its nucleus?B6. What enzymes are used in DNA Replication? Start by reading pages 506-508 *C. mRNA TranscriptionTo control the cytoplasm, DNA must get its message out of the nucleus. Theproblem is that DNA is too large a molecule to pass through the nuclearmembrane. This forces it to make a small copy of itself called mRNA to carry theDNA’s instructions bit by bit to the cytoplasm. Each “bit” is actually a single genefrom the DNA.The making of a molecule of mRNA is called Transcription. A section of DNAthat performs a certain job in the cell is called a gene. Each gene acts by buildinga molecule of mRNA.Open one of your DNA helixes. Keep the “right side” and put the other DNAnucleotides back into their correct envelope. (please!) Go get the following mRNAnucleotides from the other 4 envelopes (that say RNA): 2 guanine, 1 adenine, 2cytosine, and 1 uracil. Check to make sure that your paper nucleotides all sayribose instead of deoxyribose. Make sure that you have the correct nucleotides.Match these up with the right side of your existing DNA molecule. In a real cell,this mRNA strand that you have would leave the nucleus and carry a copy (agene) of the DNA’s message to the cytoplasm.C1. What is the difference between ribose and deoxyribose? *(use text)C2. If DNA has the bases A T T C G G C A, what will be the order of mRNA bases?C3. List 3 structural differences between a DNA and a mRNA molecule.C4. How is it ensured that the same mRNA molecule always is formed from thesame section of DNA?C5. Write out the full and correct names for DNA and RNA.C6. Explain in point form how Transcription occurs. Include all necessaryenzymes.8
D. TranslationNames:Blk:You will remember that DNA builds a complementary mRNA molecule intranscription. If we follow this mRNA molecule out of the cytoplasm, we canlearn how this molecule directs the production of a protein by the cell in a processcalled translation.1. A strand of mRNA nucleotides has the sequence U U A U C AmRNA codons (groups of 3) are read at the ribosome. What were the DNAnucleotides complementary to these codons?2. Read the description of tRNA in your text page 509 before proceeding. Howmany bases form the anti-codon sequence?3. What would be the order of tRNA bases that pair with the mRNA in question 1?Each tRNA acts like a taxi and can carry only 1 specific passenger. This passengeris an amino acid. By varying the order of these amino acids, different proteinsresult.Read the given information:Amino AcidSerineProlineLeucineGlutamic sinetRNA anti-codonAGUGGGAAUCUUAUAGCUGUUAAACAAUUU4. A protein consists of the following amino acid sequence: leucine, glutamine,tyrosine, leucine, serine. What would be the sequence of tRNA moleculesresponsible for forming a protein with AA in this order?9
5. A ribosome obtains the following mRNA message: A A A C G A G A A G U U.What will be the sequence of tRNA anti-codons joining the mRNA?6. What will be the order of the amino acids from question #5?7. What would be the sequence of the DNA molecule that originally coded forthese amino acids?8. Hemoglobin (a blood protein) has 600 amino acids. How many bases long isthe gene that directs its production?9. How does a mutation in DNA appear as a protein error?10. A section of DNA was found to be composed of 42% Guanine. Predict theamounts of the following in the remainder of the DNA section:A C U T Use page 507 in your text to fill in the table.A GAAGCCDNA strand#1TDNA strand#2mRNAUtRNAvalineserineAmino acidname10
Continuity and ChangeParadoxically, DNA has to provide for the stability of the species by accuratelyreproducing a new individual, while at the same time it has to be the source ofmutations to keep “looking” for the best organism to fit into a changingenvironment.Summary of Protein Synthesis1. In the nucleus, helicase opens the DNA molecule in the area of the gene that isto be transcribed.2. Transcriptase starts hydrogen bonding the newRNA nucleotides to the exposed DNA nucleotides.mRNA is complementary to DNA.3. The making of mRNA is called Transcription.Each sequence of three bases is called a codonsince it will code for an amino acid.4. The mRNA molecule is released from the DNA.The DNA closes.5. The mRNA leaves the nucleus out a nuclear poreand becomes associated with a ribosome. Aribosome has two binding sites where tRNAmolecules can H bond to the mRNA.6. As a tRNA arrives carrying a specific amino acidat the ribosome, it H bonds to the first 3 mRNAbases on the first binding site of the ribosome usingits 3 bases. These are called an anti-codon.7. A second tRNA arrives carrying its amino acid passenger and H bonds to themRNA on the second binding site on the ribosome. A peptide bond formsbetween the two amino acids.8. Now the ribosome moves along the mRNA the space of 1 codon. The first tRNAleaves and the second tRNA slides over into the first binding site. A third tRNAarrives and fits into the second binding site. This process of going from the“language of codons” to the “language of amino acids” is aptly calledTranslation. This process repeats itself until a “stop” codon is reached on themRNA. More ribosomes may already be copying the mRNA. The three parts oftranslation are initiation, elongation and termination. Read about this onpages 510-511 of your text.11
MutationsReference text pg. 490-91Mutations are changes in the DNA code. They are random and are not alwaysdangerous. Germinal mutations are those that occur in the sperm or egg and arepassed on to the next generation. Somatic mutations are those that occur in anindividual, but not in gametes.Types of MutationsA. Chromosomal MutationsInversion: a piece breaks off andjoins in the wrong order.Translocation: an exchange ofof pieces between non-partnerchromosomes.Deletion: loss of a pieceDuplication: a piece gets copiedB. Gene or Point MutationsThese involve only a few nucleotides within a gene, and are usually more seriousthan chromosomal mutations.Deletion – a nucleotide is left out and may cause a non-functioning protein.Substitution- one nucleotide replaces another. Ie: Sickle Cell AnemiaAddition- an extra base gets put in.Follow the example on the board for gene mutations. Relate this concept to howgene mutations are a direct result of a problem during protein synthesis.12
Causes of MutationsAnything that causes a mutation is called a mutagen. Drugs (LSD, cocaine, tobacco, alcohol)Chemicals (food additives, pesticides)Radiation13
Matching: Replication/TranscriptionMatch the term with the phrase. (check your answers up front)Chargaff’s rule1. single ring baseCrick/Watson2. won Nobel prize for DNA structurepyrimidine3. A-T C-GDNA Polymerase4. length of DNA governs a traitRNA Polymerase5. has two binding sitesribose6. a nucleotide triplettranscription7. guanine, adeninedeoxyribose8. provides a site for protein synthesisnucleotide9. phosphoric acid, 5 carbon sugar, basegene10. 1 less oxygen in its sugarribosome11. process of copying a genecomplementary base pair12. found only in mRNAcodon13. also known as Transcriptase14. Hershey-Chase15. A-G C-T16. cytosine, guanine17. same number of A’s and T’s18. occurs only in the nucleus19. proof reads a new DNA strand14
Recombinant DNA (rDNA)reference pg. 526Many bacteria contain plasmids, small independent DNA fragments that carryspecific pieces of genetic information, such as resistance to specific antibiotics orother genetic characteristics. Plasmids can be transmitted from one bacterium toanother, or from the environment into a host bacterium, in a process calledtransformation.Plasmids can also incorporate into their DNA sequence pieces of DNA fromdifferent organisms. Plasmids that incorporate new DNA are called recombinantplasmids. Recombinant plasmids are used in biotechnology to carry DNA thatcodes for substances, such as human insulin or growth hormone, into bacteria.Bacteria that contain the recombinant plasmids can then be grown commerciallyto provide the needed substance. Special enzymes, called restriction enzymes,can cut DNA fragments from almost any organism. Typically, restriction enzymesare used to cut DNA molecules into individual genes.There are many different restriction enzymes, each of which recognizes onespecific nucleotide sequence. Many restriction enzymes work by findingpalindrome sections of DNA (regions where the order of nucleotides at one end isthe reverse of the sequence at the opposite end). These two complementary endsare called “sticky ends”.15
This way a restriction enzyme can cut tiny sticky ends of DNA (complementaryends) that will match and attach to sticky ends of any other DNA that has beencut with the same enzyme. DNA ligase joins the matching sticky ends of theDNA pieces from different sources that have been cut by the same restrictionenzyme.Once a desired DNA fragment has been isolated and cut with a specific restrictionenzyme, the sticky ends of both the desired DNA fragment, and from a plasmidthat has been cut by the same restriction enzyme, can be joined together, forminga recombinant DNA plasmid. Special plasmids, which have antibiotic resistancemarkers, are used in this process so that a researcher will be able to tell that thedesired DNA has been incorporated into the target plasmid and subsequentlyinto the host bacterium.16
Genetics The Study of HeredityCharacteristics appear to be repeated from generation to generation. The passingof traits from parents to offspring is called heredity. Your biological traits arecontrolled by your genes located on the chromosomes found in your cells. Youinherited half of your 46 chromosomes from your mother and the other half fromyour father. You are therefore referred to as a diploid organism.GenesAre units of nucleotide base pairs located on the chromosomes which provideinstructions to a cell to produce a specific trait. You have about 22,000 genes (ie.the gene that produces insulin). Many genes can interact with other genes toproduce various effects.AllelesAre two or more alternate forms of a gene. An allele for black hair or blonde hairare forms of the gene for hair colour. In genetic problems, alleles are representedwith letters.Dominant AlleleThese alleles determine the expression (the way you look) of the genetic trait.Recessive AlleleThese alleles are masked by the dominant allele and are only expressed when thedominant allele is not present for that gene.GenotypeRefers to the genes (we use letter combinations) for an organism. ie (BB, Bb, bb)PhenotypeRefers to the way the genotype physically appears in an organism.HomozygousRefers to a genotype in which both alleles of a pair are identical. ie (RR, aa)HeterozygousRefers to a genotype in which the alleles of a pair are different. ie (Rr, Aa)Incomplete DominanceWhen two alleles interact and are equally dominant, they produce a newphenotype which is a blending of the two traits. ie (a red flower crosses with awhite flower to produce blended offspring: pink flowers)CodominanceBoth alleles are expressed at the same time producing a mottled effect. ie (redand white flowers make flowers with red and white specks)17
All of your body cells contain a full complement of 46 chromosomes. (23 pairs)These cells are referred to as somatic cells with autosomal chromosomes. Themale sperm cell or the female ova (egg) are called gamete cells with sexchromosomes and are the only cells to contain only ½ of this number.A gene for a particular trait can be found on one of your chromosomes. Thelocation of a gene on a chromosome is called the gene’s loci. One allele comesfrom your father while the other comes from your mother.During the formation of gametes, the alleles will segregate (separate) to ensurethat each gamete cell has only one of the alleles for that trait. Because of thisindependent assortment, a male’s sperm may contain the allele for blue eyeswhile another of his sperm may carry the allele for brown eyes. The female’s eggthat gets fertilized by the sperm may also contain an allele for either blue orbrown eyes. Both gametes carry the gene for eye colour and both gametes haveonly one allele (form) of the gene.When fertilization is complete, the first somatic cell is created. This cell is called azygote. The zygote has a full 46 chromosomes (23 pairs)This was you on day 1aren’t you cute18
Genetics Review:Alleles:B brown eyes, b blue eyes, XX female, XY male,R tongue roller r flat tongueGive the genotype of the following: if there is not enough information todetermine an answer, put a ? on the blank.a) heterozygous brown-eyed male b) a tongue rolling female c) a homozygous brown eyed person who can’t roll tongue d) a brown-eyed person heterozygous for tongue rolling Give the phenotype of the following:a) BBXYb) rrXXc) BbrrXYWrite out the F1 generation when a heterozygous tall plant crosses a dwarf plant.Use T tall and t dwarf for alleles.What are the chances of getting a blue-eyed person who cannot roll their tongueif you cross a heterozygous brown-eyed tongue roller with a blue-eyedheterozygous roller? Show the F1 generation to determine your answer.19
Sex-Linked TraitsReference text pgs. 492-94Body characteristics that are carried on the X and Y chromosome are called “sexlinked traits” because they are passed from parent to offspring on the sexchromosomes.Female chromosomeMale chromosomeTo set up a key to do Punnett squares for sex-linked traits, males and femalesmust be indicated:XC normal visionAll the possible genotypes include:Xc colour blindnessXCXC normal femaleXCXc normal female (carrier)Males have a 1/2 chanceFemales have a 1/3 chanceXcXc colour blind femaleXCY normal maleXcY colour blind maleMost sex-linked traits occur on the X chromosome simply because of the size ofthe X compared to the smaller Y chromosome.20
Do the following practice problems and check up at the front desk:Colour Blindness:A female carrier for colour blindness has children with a normal vision male.What are the chances of a colour blind daughter? If they have a son, what are thechances he will be colour blind? Show the F1 generation.Hemophilia:XH normal clotterXh bleederA male who can normall
OBJECTIVE SHEET NUCLEIC ACIDS AND PROTEIN SYNTHESIS 1. Name the four bases in DNA and describe the structure of DNA. 2. Describe the steps involved in DNA replication. Include in your discussion helicase, DNA polymerase, complementary base-pairs, anti-parallel, semi-conservative replication. 3. Describe three uses for recombinant DNA (rDNA).
NMR Spectroscopy is an Important Method for Structural Studies of Nucleic Acids: Technique !Molecule X-ray Diffraction! NMR! Other 1)! total! PDB Holding, March 21, 2012! Proteins! Nucleic Acids! Protein/Nucleic ! Acid Complexes! Other! 1) EM, Hybrid, other! 65’703 ! 8’163 !
Properties of Acids and Bases Return to the Table of contents Slide 5 / 208 What is an Acid? Acids release hydrogen ions into solutions Acids neutralize bases in a neutralization reaction. Acids corrode active metals. Acids turn blue litmus to red. Acids taste sour. Properties of Acids Slide 6 / 208 Properties
phosphorus, in addition to the usual C, H, N & O. We now know that nucleic acids are found throughout a cell, not just in the nucleus, the name nucleic acid is still used for such materials. A nucleic acid is a polymer in which the monomer uni
I can describe the structure of carbohydrates, lipids, proteins, and nucleic acids I can describe the function of carbohydrates, lipids, proteins, and nucleic acids I can identify monomers for macromolecules (carbohydrates, lipids, proteins, and nucleic acids) I can recognize common examples of macromolecules
Working with Molecular Genetics Chapter 2. Structures of Nucleic Acids labels in biology.) As diagrammed in Fig. 2.1, The proteins of T2 phage were labeled with 35S (e.g. in methionine and cysteine) and the DNA was labeled with 32P (in the sugar-phosphate backbone, as will be presented in the next section).
approaches to bring nucleic acids into contact with cellular machinery. Unlocking the Genome: Bypassing Cellular Barriers Nucleic acids are generally unable to cross phospholipid bilayer membranes unaided, and the uptake of naked nucleic acids is a relatively rare phenomenon in eukaryotic cells. Moreover, eukaryotic
(Circle one) Carbohydrates Lipids Proteins (enzymes) Nucleic Acids 4. The biomolecule that is structurally important in cell membranes is a (Circle one) Carbohydrates Lipids Proteins Nucleic Acids 5. Nucleic acids are most important in which characteristic of
2. Describe the common properties of acids and bases 3. Identify acids and bases using indicators, pH papers 4. Name some common lab acids and bases, acids at and bases at home 5. Describe reactions of acids with metals, bases and carbonates 6. Describe the application of acids, bases and p
