LO7 - Macromolecules_Nucleic Acids(2).docx

NANYANG TECHNOLOGICAL UNIVERSITY Hello and Welcome In this online session,you will learn about Macromolecules:Nucleic Acids NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences Describe the structural features common to nucleic acids; Distinguish between the types of nucleic acids in...

NANYANG TECHNOLOGICAL UNIVERSITY Hello and Welcome In this online session,you will learn about Macromolecules:Nucleic Acids NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences Describe the structural features common to nucleic acids; Distinguish between the types of nucleic acids in terms of structure and functions; Name the components of nucleic acids and apply the nomenclature of various derivatives correctly; List the complementary pairing bases for each type of nucleic acids;and Describe the directionality of nucleic acids. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences Nucleic acids are biomolecules important for their roles in the storage,transfer,and expression STORAGE, of genetic information. TRANSFER, AND There are two kinds of nucleic EXPRESSION acid: deoxyribonucleic acid (DNA) 0F and ribonucleic acid (RNA). GENETIC INFORMATION The genetic material of the cell is made of DNA. The information stored in DNA is transmitted via RNA.(You will learn more about this in the module Genetic Basis of Life.) NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences DNA and RNA are linear polymers made up of building blocks called nucleotides. Generally,RNA exists as single- stranded molecules while DNA exists as a double-stranded molecule. There are 4 types of nucleotides that make up either DNA or RNA.We abbreviate the names of the four nucleotides of DNA as A,G,C and T. For RNA,they are A,G,C and U. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences The monomericunits of nucleic acids are known as nucleotides. N select to view the video NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences The nucleotides in RNA and DNA contain different 5-carbon sugars. RIBOSE DEOXYRIBOSE For RNA,the sugar is ribose,from which we get the full name ribonucleic acid. For DNA,the sugar is deoxyribose,from which we get the name deoxyribonucleic acid 刀 Select to compare the difference between ribose and deoxyribose To distinguish between the numbers given to the carbon atoms of the nitrogenous base vs the sugar in a nucleotide structure,the carbon atoms of the sugar units are given the suffix"prime" (represented as ),after the number.Thus,the five positions within the sugar are referred to as 1',2',3',4'and 5',as shown. NANYANG TECHNOHOCA UNIVERSITY School of Biological Sdiences Comparison The difference between a ribose and a deoxyribose is the presence or absence of a hydroxyl group at the 2'position of the sugar ring. To disti sugar in prime (represented as),after the number.Thus,the five positions within the sugar are referred to as 1,2,3,4'and 5,as shown. School of Biological Sciences In a nucleotide,the ribose or deoxyribose unit is linked to: a phosphate group through the carbon at the 5'position,and a nitrogenous base through the carbon at the 1'position. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences The nitrogenous bases of DNA and RNA are classified into purines and pyrimidines. PYRIMIDINES NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences The nitrogenous bases of DNA and RNA are classified into purines and pyrimidines. PYRIMIDINES Purines have two rings in their structures.There are two types of purine;adenine (A),and guanine (G).Both can be found in DNA and RNA. N< 之 N - ADENINE NH₂ A GUANINE NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences The nitrogenous bases of DNA and RNA are classified into purines and pyrimidines. CYTOSINE THYMINE URACIL The pyrimidine,cytosine,is found in both DNA and RNA, The pyrimidine,thymine,is unique to DNA. The pyrimidine,uracil,is unique to RNA,and used in the place of thymine. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences We distinguish between the base and its derivatives by referring to them as “bases”,"nucleoside"or"nucleotides": THE NUCLEOSIDE base bonded to ribose o deoxyribose THE NUCLEOTIDE base bonded to ribose or deoxyribose and phosphate(s DENOSINE ADENOSINF AONOPHOSPHATE ! ADENOSINE M 。 DEOXYADENOSINE MONOPHOSPHATE NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences Although most of the nucleotides in a cell exist as a part of DNA or RNA,free nucleotides and their derivatives are also present in a cell.They perform numerous metabolic functions not related to the issue of genetic information.These nucleotides within the cell can be found in the mono-,di- and tri-phosphorylated forms. BASES NUCLEOTIDE DERIVATIVES: STRUCTURES NUCLEOTIDE DERINATIVES: FUNCTIONS ADENINE Select the names of the derivatives to view their structures. Adenosine triphosphate or ATP,a nudleotide triphosphate is a major energy currency of living organisms,which you will learn more about in the module Metabolism. Adenosine diphosphate (ADP)and adenosine monophosphate (AMP)are equally important nucleotides that work along with ATP as principal carriers of chemical energy in cell Other nucleotide triphosphates (GTP,UTP,etc),their di- and mono-phosphate derivatives,and their deoxy counterparts (dATP,dCTP,dGTP,dTTP,etc)participate to lesser extents in energy metabolism but are important in biosynthetic processes including the synthesis of nucleic acids, Of special importance are certain nucleotides such as GTP,cyclic AMP and cyclic GMP which are involved in cellular communication. GUANINE CYTOSINE THYMINE URACIL NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences To form nucleic acid,nucleotides are connected one by one through their phosphate groups. Specifically,the 5'-phosphate group of one nucleotide is covalently linked to the 3'-OH group of the next nucleotide. This bond is called the 3',5'- phosphodiester bond. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences DNA and RNA chains are synthesized by enzymes called DNA polymerase and RNA polymerase respectively. Energy required to form a diester bond comes from the energy stored in the bond between the a and β phosphates of nucleotide triphosphates DNA or RNA polymerases catalysethe reaction that joins the a phosphate to the free 3'hydroxyl group at the end of a growing chain (shown below). 0 -P-0< Ho —C Ho From the list below,pick out the component(s)which can be found in a nucleotide. There may be more than one correct option.Please select all options that you think are correct,and then submit. A Phosphate B Maltose C Ribose D Nitrogenous base E Deoxyribose NANYANG TECHNOLOGICAL UNIVERSITY The structure shown below is: There may be more than one correct option.Please select all options that you think are correct,and then submit. NH; A B C D E a nitrogenous base a nucleoside a nucleotide a phosphate a sugar SUBMIT The structure shown below is: There may be more than one correct option.Please select all options that you think are correct,and then submit. A a nitrogenous base B a nucleoside C a nucleotide D a phosphate E a sugar SUBMIT What type of chemical bond allows DNA or RNA to form a long polymer? There may be more than one correct option.Please select all options that you think are correct,and then submit. A Hydrogen bonds B Peptide bonds C Ester bonds bonds D Phosphodiester E Disulphide bonds NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences In a chain of DNA or RNA,the linkage between one nucleotide and the next is asymmetric, since a phosphate joins the 3'carbon of the sugar in one nucleotide to the 5'carbon of the sugar in the next nucleotide. This allows us to discern a directionality in a chain of DNA or RNA.We say that the chain "runs in the 5'to 3'direction". The phrase means that the "first"nucleotide in the nucleic acid chain is the one that has a free*5'carbon,and the "last"nucleotide is the one that has a free*3'carbon. *"free"refers to the situation whereby the -OH group of that carbon has not been used to form a phospho-diester bond. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences In a chain of DNA or RNA,the linkage between one nucleotide and the next is asymmetric, since a phosphate joins the 3'carbon of the sugar in one nucleotide to the 5'carbon of the sugar in the next nucleotide. The sequence of four bases (A,G,C,and T/U)should be read by following the 5'→3' direction of nucleic acids. We refer to the sequence of bases read in this way as the primary structure of nucleic acid. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences The bases adenine and thymine (or adenine and uracil in the case of RNA)can pair up opposite each other via two hydrogen bonds.Cytosine and guanine can do likewise via three hydrogen bonds. This pairing relationship through hydrogen bonding is known as "complementarity".Alternatively,we can refer to the situation as"the pair of bases are complementary to each other". NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences If strands of DNA or RNA are complementary,that is to say,if As are opposites to Ts (or Us)and Gs are opposite to Cs,then a double-stranded region can form. DNA is typically double-stranded:two complementary strands of DNA are paired in opposite directions by the hydrogen bonds between base A of one strand and base T of the other strand,and likewise between bases C and G. Note:RNA is often,though not always,single-stranded (within a single strand of RNA,double-stranded regions may form). NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences The two strands of double-stranded DNA are in an anti-parallel orientation.In other words,the two strands are oriented in opposite direction.Thus,at each end of a piece of linear double-stranded DNA, we can find the 5'end of one strand and the 3'end of the other. Note:RNA is often,though not always,single-stranded (within a single strand of RNA,double-stranded regions may form). NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences Double-stranded DNA most commonly adopts the conformation of a right-handed helix and this is referred to as the"B-form". This form makes one complete turn of 360° every 10.5 base pairs,or every 3.4nm. In this helical state,DNA presents a wider major groove,and a narrower minor groove. Many proteins can interact with specific DNA sequences by accessing the base-pairs through the major and/or minor grooves. For ease of visualisation, the model is represented with 10 base pairs instead of 10.5 base pairs. 3.4nm NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences Fill in the bases in the positions 1-4 for the complementary strand of the DNA below. There may be more than one correct option.Please select all options that you think are correct,and then submit. A T,G,C,A B C,A,T,G C G,T,A,C D A,C,G,T If one strand of DNA has the sequence of 5'-AGTTGCA -3'. What is the sequence on the complementary strand? A AGTTGC B ACAAGT C TGCAACT D ACGTTGA E TCAACGT There are “X"hydrogen bonds between an AT pair and "Y' hydrogen bonds between a GC pair in a DNA double helix. Which answer is correct for"X"and"Y"? There may be more than one correct option.Please select all options that you think are correct,and then submit. A X=2;Y=2 B X=2;Y=3 C X=3;Y=2 D X=3;Y=3 E X=0;Y=0 School ofBiological Sciences Check Your Understanding If one strand of a DNA has the sequence of 5'-AGTTGCA-3'. What is the sequence on the complementary RNA? A TGCAACT B AGTTGCA C TCAACGT D UGCAACU E AGUUGCA Which of the following statements are true regarding the DNA double helix? There may be more than one correct option.Please select all options that you think are correct,and then submit. A The two strands are arranged in a parallel fashion,i.e.,they have the same orientation. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences In contrast to DNA,RNA often exists as a single-stranded molecule although it forms some double-stranded regions in its secondary structure. In terms of functions,there are several types of RNA such as: The major three types (mRNA,rRNA,and tRNA)involved in copying and carrying genetic information from DNA,and involved in the process of transcription/translation (the making of a protein as directed by information stored in DNA). The fourth type:As genetic material e.g..in RNA-virus,and The fifth type:As enzyme e.g., Ribozyme. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences In contrast to DNA,RNA often exists as a single-stranded molecule although it forms some double-stranded regions in its secondary structure. In terms of functions,there are several types of RNA such as: The major three types (mRNA,rRNA,and tRNA) involved in copying and carrying genetic information from DNA,and involved in the process of transcription/translation (the making of a protein as directed by information stored in DNA). The fourth type:As genetic material e.g.,in RNA-virus,and The fifth type:As enzyme e.g., Ribozyme. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences In contrast to DNA,RNA often exists as a single-stranded molecule although it forms some double-stranded regions in its secondary structure. In terms of functions,there are several types of RNA such as: single-stranded The major three types (mRNA,rRNA,and tRNA)involved in copying and carrying genetic information from DNA,and involved in the process of transcription/translation (the making of a protein as directed by information stored in DNA). The fourth type:As genetic material e.g.,in RNA-virus,and The fifth type:As enzyme e.g.. Ribozyme. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences In contrast to DNA,RNA often exists as a single-stranded molecule although it forms some double-stranded regions in its secondary structure. In terms of functions,there are several types of RNA such as: The major three types (mRNA,rRNA,and tRNA) involved in copying and carrying genetic information from DNA,and involved in the process of transcription/translation (the making of a protein as directed by information stored in DNA). The fourth type:As genetic material e.g.,in RNA-virus,and The fifth type:As enzyme e.g., Ribozyme. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences In contrast to DNA,RNA often exists as a single-stranded molecule although it forms some double-stranded regions in its secondary structure. In terms of functions,there are several types of RNA such as: singlnded The major three types (mRNA,rRNA,and tRNA) involved in copying and carrying genetic information from DNA,and involved in the process of transcription/translation (the making of a protein as directed by information stored in DNA). The fourth type:As genetic material e.g.,in RNA-virus,and The fifth type:As enzyme e.g. Ribozyme. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences In contrast to DNA,RNA often exists as a single-stranded molecule although it forms some double-stranded regions in its secondary structure. In terms of functions,there are several types of RNA such as: The major three types (mRNA ,rRNA ,and tRNA) involved in copying and carrying genetic information from DNA,and involved in the process of transcription/translation (the making of a protein as directed by information stored in DNA). The fourth type:As genetic material e.g.,in RNA-virus,and The fifth type:As enzyme e.g. Ribozyme. Which of these RNAs is a structural component of the ribosome? There may be more than one correct option.Please select all options that you think are correct,and then submit. C Ribosomal RNA Amino acids are covalently linked to There may be more than one correct option.Please select all options that you think are correct,and then submit. A Messenger RNA B Transfer RNA C Ribosomal RNA A gene is encoded in the form of DNA and copied as There may be more than one correct option.Please select all options that you think are correct,and then submit. A Messenger RNA B Transfer RNA C Ribosomal RNA NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences In this section on Nucleic Acid,you need to take home the following messages: 1.DNA and RNA are the two types of nucleic acids found in living systems,and they differ in the type of sugar unit found in their building blocks:deoxyribose for DNA,and ribose for RNA. 2.Nucleotides are the basic building blocks of nucleic acids.Each nucleotide consists of a ribose or deoxyribose sugar,a phosphate group,and a nitrogenous base. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences In this section on Nucleic Acid,you need to take home the following messages: 3.The nitrogenous bases in DNA are A,T,Cand G while those in the RNA are A,U,C and G. 4.The bases complementarily pair in this manner-AtoT (or U), C to G. 5.Nucleotides are linked to one another through phosphodiester bonds in DNA and RNA,in the 5' to 3'direction. NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences In this section on Nucleic Acid,you need to take home the following messages: 6.DNA takes on a double-stranded helical structure,with the two strands running in opposite directions. 7.RNA may be functioning as messenger RNA(mRNA),transfer RNA(tRNA)or ribosomal RNA (rRNA).Enzymatic activities are found on some RNA and there are viruses that use RNA as their genetic material. 粤单学 NANYANG TEC S Self-Assessment Macromolecules -Nucleic Acids Total number of questions:5 BEGIN TEST School of Biological Sciences Self-Assessment Which of the following chemical groups can be found in a DNA molecule? There may be more than one correct option.Please select all options that you think are correct,and then submit. A Ribose B Deoxyribose C Cytosine D Uracil E Tyrosine School of Biological Sciences Self-Assessment In DNA,if the content of adenine is 22%,what is the content of cytosine? There may be more than one correct option.Please select all options that you think are correct,and then submit. A 11% B 22% C 28% 78% D E It cannot be determined. Self-Assessment In an mRNA, if the content of adenine is 22%, what is the content of uracil? A 11% 22% B C 28% 78% D E It cannot be determined. 联 NANYANG TECHNOLOGICAL UNIVERSITY School of Biological Sciences Classify the following carbohydrates into the respective categories: Drag the options into their correct category then click submit. Deoxyribose Ribose Nitrogenous Base Nucleoside Nucleotide School of Biological Sciences Self-Assessment Which type(s) of macromolecules is/ are able to perpetuate or transfer information in the form of a sequence of bases? A Proteins RNA B C DNA Lipids D E Carbohydrates NANYANG TECHNOLOGC VERSITY You've completed the Self-Assessment. Your score is 40 %