TMJC Biomolecules Notes

Page 1 of 142 Tampines Meridian Junior College JC1 H2/9744 Biology 2023 Core Idea 1B/1C/2A 2. Biomolecules of Life and Cellular Transport SYLLABUS OVERVIEW No. Overarching Idea Topics 1 Core Idea 1 The Cell and Biomolecules of Life Cell – The Basic Unit of Life 2 Biomolecules of Life and Cellular Transport 3 Core Idea 3 Energy and Equilibrium Transformation of Energy – Photosynthesis and Cellular Respiration 4 Core Idea 2 Genetics and Inheritance Genetics and Inheritance (I) – The Cell Cycle 5 Genetics and Inheritance (II) – DNA Replication and Gene Expression 6 Genetics and Inheritance (III) – DNA Mutations and their Consequences 7 Genetics and Inheritance (IV) – Molecular Techniques in DNA Analysis 8 Genetics and Inheritance (V) – Organization of Genome & Control of Gene Expression in Eukaryotes [Includes Core Idea 1D: Stem Cells] 9 Genetics and Inheritance (VI) – Organization and Inheritance of Viral Genomes 10 Genetics and Inheritance (VII) – Organization of Genome & Control of Gene Expression in Prokaryotes 11 Genetics and Inheritance (VIII) - Inheritance 12 Core Idea 3 Energy and Equilibrium Communication and Equilibrium in Multicellular Organisms 13 Core Idea 4 Biological Evolution Biological Evolution 14 Extension Topic A Infectious Diseases Immunity and Infectious Diseases 15 Extension Topic B Impact of Climate Change on Animals & Plants Climate Change – Causes and Impacts on Animals and Plants Before 1st lecture: Pls complete and mark questions on pgs 5 and 6.

Page 2 of 142 TOPIC SYNOPSIS Core Idea 1: The Cell & Biomolecules of Life – entails the study of cells, which are the basic units of life. The following questions should help you frame your learning: o How are the structures of biomolecules related to their functions? o How do cells regulate the movement of substances into and out of themselves; and what are the implications of such movements? Biomolecules make up cells and cells regulate the m ovement of substances into and out of themselves and cellular processes through membranes The different classes of biomolecules (sugars, lipids, proteins and nucleic acids) function as molecular building blocks for macromolecules to be assembled. Nucleic acids, which include DNA and RNA, are made from monomers known as nucleotides. Phospholipids, cholesterol, carbohydrates and proteins are important components in biological membranes. Cells need to regulate the movement of substances into and out of themselves. Substances such as water, oxygen, glucose, minerals are important in the synthesis of new molecules and important cellular processes. According to the fluid mosaic model, cell membranes are selectively permeable due to the nature of the phospholipids and proteins from which they are made. The movement of different molecules depends on the nature of the substances through transport processes such as osmosis, diffusion and active transport. Membranes allow cells to create and maintai n internal environments that are different from external environments. Proteins, which are class of biomolecules, play a significant role in cells Proteins play a variety of roles in cells including structural, transport, enzymatic and signalling funct ions. They are essential for biological processes and functions, such as chemiosmosis, protein synthesis, cell signalling, immunology and blood glucose homeostasis. Protein structure can be affected by temperature and pH. Enzymes are an important group of proteins that control many biological reactions. The functions of these proteins will be revisited in other core ideas.

Page 3 of 142 LEARNING OUTCOMES Core Idea 1B: Biomolecules of Life and Cellular Transport This concept focuses on how the structures of biomolecul es give rise to properties that allow these biomolecules to carry out their functions. One of these functions involves regulating transport of substances into and out of the cell. This regulation is afforded by the properties of the cell membrane, which co mprise phospholipids and proteins. Regulation of the movements is important for several biochemical processes to occur. Candidates should be able to: g) Describe the structure and properties of the following monomers: i) α-glucose and β-glucose (in carbohydrates) ii) glycerol and fatty acids (in lipids) iii) amino acids (in proteins) (chemical formulae of specific R -groups of different amino acids are not required). h) Describe the formation and breakage the following bonds: i) glycosidic bond ii) ester bond iii) peptide bond i) Describe the structure and properties of the following biomolecules and explain how these are related to their roles in living organisms: i) starch (including amylose & amylopectin) ii) cellulose iii) glycogen iv) triglyceride v) phospholipid j) Explain the fluid mosaic model and the roles of the constituent biomolecules (including phospholipids, proteins, glycolipids, glycoproteins and cholesterol) in cell membranes. k) Outline the function of membranes at the surface of cells and membranes within the cell. l) Explain how and why different substances move across membranes through simple diffusion, osmosis, facilitated diffusion, active transport, endocytosis and exocytosis. Core Idea 2A: The Structure of Nucleic Acids and Gene Expression The structure of DNA was proposed by Watson and Crick in 1953. With an understanding of DNA structure, experimental evidence supported the proposal that DNA replicates in a semi -conservative manner. The central dogma states that genetic information is encoded in the DNA and transferred to the mRNA during transcription. In addition to mRNA transcription, tRNA and rRNA are transcribed; tRNA is needed during translation while rRNA is a component of ribosomes. In eukaryotic transcription, pre-mRNA is synthesised and then processed to produce mature mRNA. Subsequently, through translation, the information on the mRNA is used to synthesise polypeptides, which are folded into functional proteins a) Describe the structure and roles of DNA and RNA (tRNA, rRNA and mRNA). (Mitochondrial DNA is not required)

Page 4 of 142 Core Idea 1C: Proteins Proteins play a variety of roles in structural, transport, enzymatic and signalling functions. This concept focuses on the structure and properties of proteins and how temperature and pH may contribute to denaturation of proteins. The structure of a protein is related to its function. m) Explain primary structure, secondary structure, tertiary structure and quaternary structure of proteins, and describe the types of bonds that hold the molecule in shape (hydrogen, ionic, disulfide bonds and hydrophobic interactions). n) Explain the effects of temperature and pH on protein structure. o) Describe the molecular structure of the following proteins and explain how the structure of each protein relates to the function it plays: i) haemoglobin (transport) ii) collagen (structural) iii) G-protein linked receptor (signalling) (Details of the number of amino acids, types of secondary structures present are not required.) p) Explain the mode of action of enzymes in terms of an active site, enzyme-substrate complex, lowering of activation energy and enzyme specificity using the lock-and-key and induced-fit hypothesis. q) Investigate and explain the effe cts of temperature, pH, enzyme concentration and substrate concentration on the rate of an enzyme-catalysed reaction by measuring rates of formation of products (e.g. measuring gas produced using catalase) or rate of disappearance of substrate (e.g. using amylase, starch and iodine). r) Describe the structure of competitive and non-competitive inhibitors with reference to the binding sites of the inhibitor. s) Explain the effects of competitive and non -competitive inhibitors (including allosteric inhibitors) on