NUSH BL1131 Notes

BL1131 Notes Foundations in Biology I Topics 1 to 7 This is a compilation of topics taught in BL1131 Semester 1 and Semester 2. Made by LQ …who hates bio. Why does bio exist AHHHHHH Links of All LQ Notes: LQ Notes Links Document Topic Topic 1: Organisms and the Environment Topic 2: Biological Molecules (I) - Nutrients Topic 3: Cell Structure and Organisation Topic 4: Movement of Substances Topic 5: Biological Nutrients (II) - Enzymes Topic 6: Nutrition in Animals Topic 7: Nutrition in Plants Topic 8: Transport in Plants (new in 2023, found in 2023 BL2131 Notes as Topic 1) Year 2 Biology Notes can be found here: BL2131 Notes Note Topic 1 - Organisms and the Environment and Topic 3 - Cell Structure and Organisation are NOT tested for (2022) end-of-year exams.

Topic 1: Organisms and the Environment 1.1 Ecology 1.1.1 Abiotic and Biotic Factors in the Environment Biotic (Living) Abiotic (Non-living) No. of Prey No. of Plants No. of Predators pH level Temperature Light intensity Photosynthesis Water availability Salinity (Salt Content) Oxygen concentration Note: Chemical Processes like photosynthesis are considered Abiotic. 1.1.2 Ecological Organisational Levels Species ⟶ Population ⟶ Community ⟶ Ecosystem ⟶ Biosphere 1. Species: A species is a group of similar organisms. Organisms within a species can breed and produce healthy(viable) offspring that can grow, develop and reproduce normally. 2. Population: A population is a group of organisms of the same species that live together at a particular time and place. 3. Community: A community is two or more populations of different species that live together in a particular place and time and interact with each other. 4. Ecosystem: An ecosystem is a community together with the abiotic environment. 5. Biosphere: A biosphere is the sum of all ecosystems. It includes all the parts of the earth where life can be found. 1.1.3 Interactions Between Species Mutualism + + Commensalism + 0 Predation (Parasitism) + - Amensalism - 0

Competition - - 1.1.4 Transfer of Energy Through the food chain, energy is transferred from one trophic level to the next. However, through each trophic level, only about 10% of the energy is transferred, while the rest of the energy is lost through 1. Heat 2. Excretion (Sweat, Urination) 3. Egestion (Faeces) 4. Uneaten Parts 1.1.5 Assimilated Energy Assimilated Energy is the total energy, including the energy that is lost through heat, excretion, egestion and uneaten parts. It is the total efficiency of animals to convert ingested food into energy for 1. Growth 2. Reproduction 3. Movement 1.1.6 Bioaccumulation and Bioamplification Harmful chemicals like DDT are not biodegradable and hence remain in the soil and water for many years. They are not water-soluble and cannot be excreted, and hence are stored in the fatty tissues of the consumer when ingested, increasing in concentration as the consumer consumes prey. This is known as bioaccumulation. The chemicals increase in concentration as it moves up the food chain. This is known as bioamplification. 1.1.7 Ecological Pyramids The ecological pyramids are 1. Pyramid of numbers (The number of each species) 2. Pyramid of biomass (The amount of biomass/dry mass of each species) 3. Pyramid of energy (The total energy of each species)

Topic 2: Biological Molecules (I) - Nutrients 2.1 Carbohydrates Carbohydrates are made of Carbon, Hydrogen and Oxygen . They are classified into three types: Monosaccharides, Disaccharides and Polysaccharides. 2.1.1 Monosaccharides Monosaccharides have 1 carbon ring, Three monosaccharides are glucose , fructose and galactose . They are all reducing sugars . (See 2.1.6 - Benedict’s solution test) Glucose Fructose Galactose Table 2.1.1a Note: These molecules are not actually coloured, colours just for better identification 2.1.2 Disaccharides Disaccharides have 2 carbon rings. Three disaccharides are maltose , sucrose and lactose . Maltose and Lactose are reducing sugars , while Sucrose isn’t. (See 2.1.6 - Benedict’s solution test) Maltose Sucrose Lactose Table 2.1.2a Note: These molecules are not actually coloured, colours just for better identification 2.1.3 Polysaccharides Polysaccharides have many carbon rings. Three polysaccharides are starch, cellulose and glycogen.

Polysaccharides in Plants Polysaccharides in Animals Starch Cellulose Glycogen Table 2.1.3a These polysaccharides are all polymers (Polymer: a molecule with repeating structures). Review WS 4, Question 7 (a) (ii) Cellulose is a component of plant cell walls, while chitin is a component of fungal cell walls. Suggest why chitin, like cellulose, is used to build cell walls. [1] Answer Chitin is rigid/tough/strong. [1] Note: Cellulose and Chitin are both relatively strong. 2.1.4 Disaccharides Forming Disaccharides are formed through a condensation (or dehydration) reaction . FYI: The reaction is called condensation because water is one of its products. Diagram 2.1.4a 2.1.5 Breaking Down of Disaccharides Disaccharides are broken down through a hydrolysis reaction.

Diagram 2.1.5a Note: Maltase is an enzyme , which is covered in Topic 6: Nutrition in Animals 2.1.6 Benedict’s Solution Test When Benedict’s solution is added to a type of sugar, it can tell us whether the sugar is a reducing sugar, and a rough estimate of how much reducing sugar is present. Blue Green/Yellow Orange Brick-red No Reducing Sugar Traces of Reducing Sugar Moderate amounts of Reducing Sugar Large amounts of Reducing Sugar Table 2.1.6a Reducing Sugars Non-reducing Sugars Glucose, Fructose, Galactose (Monosaccharides) Maltose, Lactose (Disaccharides) Sucrose (Disaccharide) Note: Sucrose is the only non-reducing sugar. Table 2.1.6b 2.1.7 Iodine Starch Test When Iodine (I 2 ) is added to a substance, it can tell us if starch is present. Iodine is brown, but when it is added to a substance where starch is present, it turns blue-black. This is the Iodine Test or Iodine Starch Test. 2.2 Fats Fats are made of Carbon, Hydrogen and Oxygen . They are Lipids , which is a group of molecules that do not mix well with water. Fats are also triglycerides . This means that they are made of (1) glycerol and 3 fatty acids.

Diagram 2.1.7a FYI: Lipase is the enzyme that breaks down lipids; This is covered in Topic 6: Nutrition in Animals. 2.2.1 Ethanol Emulsion Test Lipids like fats react with ethanol, a colourless liquid, and will form a white emulsion (Emulsion: A “cloud” of chemicals). This is known as the Ethanol Emulsion Test. 2.3 Proteins Proteins are made of C