Year 9 Science Classwork PDF

Year 9 Science – Term 4 Week 9 Classwork Year 9 Science Revision Name: Class:  IC OG The distance between insanity and genius is measured only by success....

Year 9 Science – Term 4 Week 9 Classwork Year 9 Science Revision Name: Class:  IC OG The distance between insanity and genius is measured only by success. Bruce Feirstein PL TO 2 Toplogic – Science Scientific Method of Inquiry IC The scientific method is a system of asking questions and making observations to find new discoveries and build scientific knowledge. Example 1: Match the term to its correct definition: (terms are question, hypothesis and aim) : A testable prediction about the relationship between the indepen- dent and dependent variables of a investigation, based on logical inference and secondary research. : A query that the researcher seeks to answer through the investiga- OG tion, which guides their research process. : A goal that the researcher aims to achieve through the investigation, which outlines the intended outcomes. Experimental Validity and Bias Validity is the extent to which an investigation addresses the aim. In other words, it proposes the question: are all the changes observed in the dependent variable a result of changes made to the independent variable? PL Bias in experiments occurs when systematic errors influence the results. Understanding and controlling the biases present in an investigation is essential to obtain valid conclusions. Example 2: Describe how confirmation bias could affect the design and interpretation of a study investigating the health benefits of a new diet............................................................................................................................................................................................................................................................................ TO......................................................................................... 3 Toplogic – Science  Example 3: A study is conducted on the impact of exercise on mental health. The researchers asked a group of members of the fitness club to participate in the study and IC concluded that regular exercise leads to significantly better mental health. 1. Explain how the bias present in this study can affect validity................................................................................................................................................................................................................................................................................................................................................. OG 2. Propose two ways the researchers could redesign the study to mitigate this bias..................................................................................................................................................................................................................................................................................................................................................................................................................................... PL Experimental Design Errors and Mistakes Example 4: The speedometer on a car intentionally displays a speed higher than the actual speed of the car. What type of error does this represent, and why is this an intentional safety feature?......................................................................................... TO............................................................................................................................................................................................................................................................................................................................................................................................................................................................. 4 Toplogic – Science  IC Units A unit is a standardised value of a physical quantity being measured. Measurements have no physical meaning if they have not been expressed in terms of a unit. Example 5: State the SI or derived unit for the following physical quantities. 1. Length OG.................................................................................... 2. Temperature.................................................................................... 3. Force.................................................................................... 4. Frequency.................................................................................... PL Significant Figures Example 6: State how many significant figures the following quantities are expressed to, and whether the number of significant figures is ambiguous. 1. 32 s TO.................................................................................... 2. 0.07 g.................................................................................... 3. 8.02 × 105 km.................................................................................... 5 Toplogic – Science  4. 620 W IC.................................................................................... Uncertainty Scientists use uncertainty to quantify their confidence in the value of a measurement by stating the margin of error. Uncertainty, whether expressed in absolute terms or as a percentage, is always written to one significant figure. OG The uncertainty of a single measurement is half of the smallest division of the measuring apparatus used. The uncertainty of a measurement based on a small number of trials is calculated using half of the range of values in the trials. The uncertainty of a measurement based on a large number of trials is calculated using using the standard deviation of the values in the trials. Measurements agree with each other if their uncertainties overlap with each other. Example 7: A group of students performed an experiment attempting to determine the charge on an electron, which is known to have a value of 1.602 × 10−19 C. Henry produced PL a result of (1.55 ± 0.04) × 10−19 C, and Charlene produced a result of (1.9 ± 0.4) × 10−19 C. 1. Which of the students’ results agree with the known value?........................................................................................................................................................................ 2. Explain how precision and accuracy affect the interpretation of the students’ results relative to the known value. TO.................................................................................................................................................................................................................................................................................................................................................................................................................................... 6 Toplogic – Science Data Analysis IC Example 8: A ball is dropped from rest from different heights, and its time to hit the ground is recorded in the table below. The height h that a ball falls in time t is known to follow the equation h = 12 gt2 , where g is the acceleration due to gravity measured in m s−2. Height (m) Time (s) Time2 (s2 ) 0.5 0.35 1.0 0.46 1.5 0.57 2.0 0.68 OG 2.5 0.73 3.0 0.81 1. Complete the missing column in the table. 2. Plot an appropriate graph that will allow a linear line of best fit to be constructed. PL TO 7 Toplogic – Science  3. Find the gradient, and hence, determine the acceleration due to gravity. IC................................................................................................................................................................................................................................................................................................................................................ OG Biomolecules Biomolecules are simply defined as essential components of living organisms, performing a wide variety of functions that are vital for life. Example 9: List the four main types of biomolecules in the human body................................................................................................................................................................................... PL Carbohydrates Example 10: Differentiate between monosaccharides, disaccharides and polysaccharides............................................................................................................................................................................................................................................................................ TO........................................................................................................................................................................................................................................................................... 8 Toplogic – Science  Example 11: What are the main functions of carbohydrates? IC...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... OG......................................................................................... Lipids Lipids are fatty, waxy, or oily compounds that are soluble in organic solvents and insoluble in polar solvents such as water. Example 12: Define fatty acids. PL......................................................................................... Example 13: List the main function of lipids............................................................................................................................................................................................................................................................................ TO Proteins A protein is a naturally occurring, extremely complex substance that consists of amino acids joined by peptide bonds. Proteins are present in all living organisms and include many essential biological compounds such as enzymes, hormones, and antibodies. 9 Toplogic – Science  Example 14: Complete the following definitions. Amino acids are: IC Peptide bonds are: OG PL Example 15: List and describe the levels of structure in proteins.......................................................................................... TO........................................................................................................................................................................................................................................................................... The main functions of proteins include: enzyme activity, transport, structure, and immune defence. 10 Toplogic – Science  Example 16: Describe examples of the functions of proteins. IC...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... Nucleic Acids OG Nucleic acids are large biomolecules that play essential roles in all cells and viruses. A major function of nucleic acids involves the storage and expression of genomic information. Example 17: What are the two main nucleic acids in the human body? Describe their structure.......................................................................................... PL............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... TO.................................................................................................................................................................................. 11 Toplogic – Science  Example 18: Discuss the main functions of nucleic acid. IC...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... OG.................................................................................................................................................................................................................................................................................................................................................................... Enzymes Enzymes are specialised protein molecules that act as biological catalysts in living organisms, PL and they catalyze only one specific reaction or type of reaction due to their unique 3D structures. They work by lowering the activation energy needed for a reaction, allowing it to occur faster. Example 19: Define what a catalyst is.......................................................................................... TO 12 Toplogic – Science  Example 20: Describe the general structure of enzymes. IC...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... OG 1. Enzymes are sensitive to temperature changes, Each enzyme has an unique op- timum temperature, where its activity is highest. Increasing temperature generally speeds up the reaction as molecules move faster and collide more frequently. 2. Enzymes also have an optimum pH level. For example, pepsin, a stomach enzyme, works best in highly acidic environments (around pH 2), while amylase, in the saliva, operates optimally around pH 7. Under extreme heat and pH levels, enzymes can denature. PL Example 21: Describe a denatured enzyme................................................................................................................................................................................... Metabolic Pathways TO Metabolic pathways are series of linked chemical reactions in cells. Enzymes play a vital role in these pathways by controlling the rate and direction of reactions to ensure efficient cell function. These pathways are essential for maintaining cellular homeostasis and supporting life functions like energy production, growth, and response to environmental changes. 13 Toplogic – Science  Example 22: Define catabolic and anabolic pathways. IC.................................................................................................................................................................................. Photosynthesis and Cellular Respiration The source of all energy in ecosystems on Earth is sunlight. Plants play a very important role in OG catching some of this energy and converting it into a form that both they and other organisms can use. Example 23: State the word and balanced chemical equations of photosynthesis............................................................................................................................................................................................................................................................................ PL Photosynthesis occurs in two stages in the chloroplast: light dependent reactions and light independent reactions. TO 14 Toplogic – Science Example 24: Discuss what occurs in the light dependent reactions. IC...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... OG.................................................................................................................................................................................................................................................................................................................................................................... Example 25: Discuss what occurs in the light independent reactions.......................................................................................... PL............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... TO.................................................................................................................................................................................. 15 Toplogic – Science  Example 26: In the space below, construct a flowchart of how sunlight is converted into chemical energy stored in glucose over the course of photosynthesis. IC OG Unlike plants, animals cannot convert light energy into chemical energy. Our energy and nutritional demands are met by taking in or consuming other organisms. That is why we and PL other organisms with this need are called consumers or heterotrophs. Example 27: Differ between autotrophs and heterotrophs, including examples..................................................................................................................................................................................................................................................................................................................................................................... TO.................................................................................................................................................................................. 16 Toplogic – Science  Example 28: State the word and balanced chemical equations of cellular respiration. IC........................................................................................................................................................................................................................................................................... Cellular respiration involves many steps, which can be divided into three main stages: glycol- ysis, the citric acid cycle, and the electron transport chain. OG PL Example 29: Describe each step of cellular respiration................................................................................................................................................................................... TO...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 17 Toplogic – Science......................................................................................... IC...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... Example 30: related. OG Explain how the processes of photosynthesis and cellular respiration are............................................................................................................................................................................................................................................................................................................................................................................................................................................................. PL............................................................................................................................................................................................................................................................................................................................................................................................................................................................. TO 18 Toplogic – Science Genetics IC DNA is made up of repeating units called nucleotides. Each of these nucleotides consisted of a sugar, a phosphate group and a nitrogenous base. Example 31: List the four different types of nitrogenous bases found in DNA................................................................................................................................................................................... OG Example 32: Describe the concept of base pairing............................................................................................................................................................................................................................................................................ Example 33: Use the concept of base pairing to complete the complementary strand for: GATTACA PL......................................................................................... RNA is a type of nucleic acid and is made up of nucleotides. Its nucleotides, however, are different from those of DNA. It is also shorter and single-stranded. Example 34: List the four different types of nitrogenous bases found in RNA. TO.................................................................................................................................................................................. 19 Toplogic – Science Replication DNA replication is simply put the exact copying of a cell’s DNA. However, this is no simple IC task. Example 35: Describe how DNA replication is semi conservative............................................................................................................................................................................................................................................................................ OG......................................................................................... Example 36: State the main enzymes involved in DNA replication, and their function..................................................................................................................................................................................................................................................................................................................................................................... PL......................................................................................... Example 37: Discuss the process of DNA replication........................................................................................................................................................................................................................................................................... TO...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 20 Toplogic – Science......................................................................................... IC.................................................................................................................................................................................................................................................................................................................................................................... OG Transcription Transcription is the process of creating a complementary RNA copy of a sequence of DNA. It is the first step in gene expression, leading to protein synthesis. The first step in making a protein involves the unzipping of the gene’s DNA. When the relevant part of the DNA strand is exposed, a special copy of the sequence is produced in the form of mRNA. Example 38: Recall what mRNA is.......................................................................................... PL Example 39: Discuss the process of DNA transcription.............................................................................................................................................................................................................................................................................................................................................................................................................................................................. TO............................................................................................................................................................................................................................................................................................................................................................................................................................................................. 21 Toplogic – Science Translation Translation is the process by which the information in mRNA is used to synthesize a protein. IC Once the mRNA has reached the ribosome, its message needs to be translated into a protein. The ribosome and another type of molecule called transfer RNA (tRNA) are involved in this process. tRNA already located in the surrounding cytosol collects and transfers the appropriate amino acid to its matching code on the mRNA. These amino acids are joined together by peptide bonds to make a protein. Example 40: Identify what a codon is.......................................................................................... OG......................................................................................... Example 41: If the codon U G C exists on the mRNA chain, what is its anticodon?......................................................................................... Example 42: Discuss the process of DNA translation PL............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... TO........................................................................................................................................................................................................................................................................... 22 Toplogic – Science Forensic Science IC Search Tactics Example 43: What types of search tactics are used by the Crime Scene Units (CSUs)?........................................................................................................................................................................................................................................................................... OG............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... PL Types of Evidence Example 44: What are the two major types of evidence? Discuss some examples and use cases of both............................................................................................................................................................................................................................................................................ TO........................................................................................................................................................................................................................................................................... 23 Toplogic – Science......................................................................................... IC........................................................................................................................................................................................................................................................................... Evidence Analysis OG Example 45: Discuss how chromatography works, and when it may be used in forensic analysis....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... PL......................................................................................... Forensic Applications:........................................................................................................................................................................................................................................................................... TO Example 46: Discuss how spectroscopy works, and when it may be used for analysis............................................................................................................................................................................................................................................................................ 24 Toplogic – Science......................................................................................... IC......................................................................................... Forensic Applications:........................................................................................................................................................................................................................................................................... Toxicology OG Example 47: Discuss the concept of LD50. What can it tell investigators about a substance found at the crime scene?.................................................................................................................................................................................. PL........................................................................................................................................................................................................................................................................... Forensic Applications:.................................................................................................................................................................................. TO......................................................................................... 25 Toplogic – Science Blood and Urine Analysis IC Example 48: What is the difference between finding a compound in blood, over urine analysis? Discuss different use cases for either............................................................................................................................................................................................................................................................................ Forensic Applications: OG........................................................................................................................................................................................................................................................................... PL TO 26 Toplogic – Science