Campbell Biology Chapter 5 PDF

Campbell Biology Third Canadian Edition Chapter 5 The Structure and Function of Large Biological Molecules Copyright © 2021 Pearson Canada, Inc. 5-1 Concept 5.5: Nucleic Acids Store, Transmit, and Help Express Hereditary Information The amino acid sequence of a polypeptide is programmed by a unit of...

Campbell Biology Third Canadian Edition Chapter 5 The Structure and Function of Large Biological Molecules Copyright © 2021 Pearson Canada, Inc. 5-1 Concept 5.5: Nucleic Acids Store, Transmit, and Help Express Hereditary Information The amino acid sequence of a polypeptide is programmed by a unit of inheritance called a gene Genes are made of DNA, a nucleic acid made of monomers called nucleotides Copyright © 2021 Pearson Canada, Inc. 5-2 The Roles of Nucleic Acids There are two types of nucleic acids – Deoxyribonucleic acid (DNA) – Ribonucleic acid (RNA) DNA provides directions for its own replication DNA directs synthesis of messenger RNA (mRNA) and, through mRNA, controls protein synthesis – Process referred to as gene expression Protein synthesis occurs on ribosomes Copyright © 2021 Pearson Canada, Inc. 5-3 DNA → RNA → Protein Figure 5.22 DNA RNA protein. Copyright © 2021 Pearson Canada, Inc. 5-4 The Structure and Function of Large Biological Molecules (3 of 4) THINK PAIR SHARE You are looking at the organization of gene expression in a eukaryotic cell, think of how it is different in a prokaryotic cell? Figure 5.22 DNA RNA protein. Copyright © 2021 Pearson Canada, Inc. 5-5 The Components of Nucleic Acids (1 of 4) Nucleic acids are polymers called polynucleotides Each polynucleotide is made of monomers called nucleotides Figure 5.23ab Components of nucleic acids. Copyright © 2021 Pearson Canada, Inc. 5-6 The Components of Nucleic Acids (2 of 4) Nucleoside = nitrogenous base + sugar Nucleotide = nucleoside + phosphate group Figure 5.23c1 Components of nucleic acids. Copyright © 2021 Pearson Canada, Inc. 5-7 The Components of Nucleic Acids (3 of 4) There are two types of nitrogenous bases: Figure 5.23c1 Components of nucleic acids. Pyrimidines (cytosine, thymine, uracil) have a single six-membered ring Purines (adenine, guanine) have a sixmembered ring fused to a five-membered ring Copyright © 2021 Pearson Canada, Inc. 5-8 The Components of Nucleic Acids (4 of 4) In DNA, the sugar is deoxyribose In RNA, the sugar is ribose Figure 5.23c2 Components of nucleic acids. Copyright © 2021 Pearson Canada, Inc. 5-9 Nucleotide Polymers Adjacent nucleotides are joined by covalent bonds formed between -OH group on 3 carbon of one nucleotide and phosphate on 5 carbon on next Links create sugar-phosphate backbone with nitrogenous bases as appendages Sequence of bases in a DNA or mRNA polymer is unique for each gene Copyright © 2021 Pearson Canada, Inc. 5 - 10 The Structures of DNA and RNA Molecules (1 of 3) DNA molecules have two polynucleotides spiraling around an imaginary axis, forming a double helix Figure 5.24a1 The structures of DNA and tRNA molecules. In DNA double helix, two backbones run in opposite 5→ 3 directions from each other, an arrangement referred to as antiparallel One DNA molecule includes many genes Copyright © 2021 Pearson Canada, Inc. 5 - 11 The Structures of DNA and RNA Molecules (2 of 3) DNA bases in opposite strands pair by hydrogen bonding: adenine (A) always with thymine (T), and guanine (G) always with cytosine (C) Figure 5.24a The structures of DNA and tRNA molecules. Complementary base pairing – This structural feature makes it possible for cell to generate two identical copies of DNA for cell division Copyright © 2021 Pearson Canada, Inc. 5 - 12 The Structure and Function of Large Biological Molecules (4 of 4) THINK PAIR SHARE In a 1 million base fly genome there are 350,000 cytosines, how many guanines, adenines and thymines are there? Copyright © 2021 Pearson Canada, Inc. 5 - 13 The Structures of DNA and RNA Molecules (3 of 3) RNA molecules are usually single-stranded Figure 5.24b The structures of DNA and tRNA molecules. Complementary pairing can occur between two RNA molecules or within same molecule In RNA, thymine is replaced by uracil (U) so A and U pair Copyright © 2021 Pearson Canada, Inc. 5 - 14 Video: Stick Model of DNA (Deoxyribonucleic Acid) Copyright © 2021 Pearson Canada, Inc. 5 - 15 Concept 5.6: Genomics and Proteomics Transformed Biological Inquiry and Applications Once the structure of DNA and its relationship to amino acid sequences was understood, biologists sought to “decode” genes, by uncovering their base sequences The first DNA sequencing techniques were developed in the 1970s Deciphering the complete DNA sequence of an organism’s genome can be very informative DNA sequencing methods are now very rapid, thanks to Human Genome Project The genomes of many organisms have now been sequenced, generating vast amounts of data Copyright © 2021 Pearson Canada, Inc. 5 - 16 Genomics and Proteomics Bioinformatics uses computational approaches to deal with the data resulting from the sequencing of many genomes Genomics refers to the analysis of large sets of genes, or comparisons of whole genomes of different species Proteomics is the analysis of large sets of proteins, including their amino acid sequences Copyright © 2021 Pearson Canada, Inc. 5 - 17 DNA and Proteins as Tape Measures of Evolution The sequences of genes and their protein products document the hereditary background of a species DNA nucleotide sequences are passed from parents to offspring Two closely related species are more similar in DNA than distantly related species Molecular biology can be used to assess evolutionary kinship Copyright © 2021 Pearson Canada, Inc. 5 - 18 Analyzing polypeptide sequence data Copyright © 2021 Pearson Canada, Inc. 5 - 19