Exam Retest Study Review PDF
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This document appears to be study notes or review material for a biology exam. It covers topics including characteristics of living organisms, the nature of science, and Darwin's theory of evolution. The document includes practice questions.
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EXAM RETEST STUDY REVIEW (9/26) Chapter 1: The Science of Biology 1.1 The Science of Life iology: Unifies natural science and studies the most complex chemical systems on B Earth. ❖ Chemistry and physics dictate how life operates. ❖ Modern science combines fields like...
EXAM RETEST STUDY REVIEW (9/26) Chapter 1: The Science of Biology 1.1 The Science of Life iology: Unifies natural science and studies the most complex chemical systems on B Earth. ❖ Chemistry and physics dictate how life operates. ❖ Modern science combines fields like chemistry, physics, and biology. haracteristics of Living Organisms: C 1.Cellular organization: All living things are made up of one or more cells, which are the basic units of life. Cells are organized structures that perform all the functions necessary for life. .Ordered complexity: Living organisms exhibit a high degree of complexity and 2 organization. This complexity comes from the interactions of various biological molecules and systems. Even within a single cell, there’s a complex organization of molecules that work together. .Sensitivity to environment: All living organisms respond to stimuli in their 3 environment. ❖ Plants can grow toward light, and animals can react to changes in temperature or threats. .Growth, development, reproduction: Living organisms have the ability to grow 4 and develop over time and reproduce to pass on their genetic material to the next generation, ensuring the continuity of life. .Energy utilization: Organisms take in energy (from food, sunlight, etc.) and use it 5 to power processes necessary for life. ❖ Humans metabolize food to generate energy for bodily functions, plants perform photosynthesis. .Homeostasis: The ability of organisms to maintainstableinternal conditions 6 despite changes in their external environment. ❖ Humans maintain a constant body temperature even when the external temperature changes. .Evolutionary adaptation: Over time, populations of organisms evolve to adapt to 7 their environment through changes in their genetic material. This process allows species to survive changes in their habitat. Hierarchical Organization of Life: Cellular Level: Atoms → Molecules → Organelles → Cells (Cell Theory) Organismal Level: Tissues → Organs → Organ Systems Populational Level: Populations → Communities → Ecosystems → Biosphere 1.2 The Nature of Science Science: Aims to understand the natural world through observation and reasoning. escriptive Science: Involves observing and classifying all life on Earth. D Hypothesis-Driven Science: Uses a systematic approach to understanding. ypothesis: A possible explanation that must be tested and refined. It generates H predictions that can validate or reject the hypothesis. Experimentation: Tests hypotheses by controlling variables and comparing a test experiment with a control experiment. Example… ➔ Observation: “I want to do well on an exam.” ➔ Hypothesis: “If I study, I’ll get a good grade on the test.” ➔ Experiment: Studying and then taking the exam. ➔ Data Collection: The grade you receive. ➔ Conclusion: Based on your performance, you wouldeither support or reject your hypothesis. old Foil Experiment: Conducted by Ernest Rutherford, the experiment showed that G atoms have a small, dense nucleus. Alpha particles were directed at thin gold foil, and while most passed through,some were deflected,indicating a central nucleus. I nductive vs Deductive Science: Inductive Reasoning: Starts with observations or data and moves toward general conclusions. ❖ O bserving that all birds you’ve seen can fly and concluding that all birds can fly (though this isn’t always true). Deductive Reasoning: Starts with a general theory or principle and applies it to specific cases. ❖ If all mammals have lungs, and whales are mammals, then whales must have lungs. asic Research: Basic research is conducted to increase our understanding of B fundamental principles. It is not aimed at solving a specific problem but adds to the general knowledge. ❖ Studying how certain enzymes work inside cells without focusingon anydirect application. escriptive Science: Descriptive science is the process of collecting and analyzing D data to describe phenomena in the natural world. It’s often the first step before forming hypotheses or theories. ❖ Cataloging different plant species in a rainforest. 💡 Theory vs Law in Science: Atheoryexplainswhysomething happens (based on evidence and reasoning). ❖ The theory of evolution explains how species change over time. Alawdescribeswhathappens butdoesn’t explain why(usually a concise, universal statement). ❖ The law of gravity, which tells us objects fall, but not why they do so. 1.3 Darwin and Evolution arwin’s Contribution: Proposed natural D selection as the mechanism for evolution. ❖ Observations on the HMS Beagle: Species like the Galápagos finches demonstrated “descent with modification” (evolution). Influence of Malthus: Populations grow geometrically while resources increase arithmetically, resulting in natural population limitations. vidence Supporting Darwin’s Theory: E Fossil Record: Transitional forms show evolutionary changes. Earth’s Age: Estimated at 4.5 billion years. Comparative Anatomy: omologous Structures: Same evolutionary origin but different functions (e.g., H vertebrate limbs). - Forelimbs of humans, whales, and bats. Despite havingdifferent functions (grasping, swimming, flying), they share the same bone structure. nalogous Structures: Different origin, same function (bird vs. butterfly wings). A wings of birds and insects; they both allow flight, but they evolvedindependently. olecular Evidence: Phylogenetic trees based on genome/protein comparisons show M evolutionary relationships. 1.4 Core Concepts in Biology Life and Laws: Biological systems follow the laws of chemistry and physics. Structure Determines Function: The structure of a biological feature reveals its function. Energy and Matter Transformation: Life continuously transforms energy (e.g., solar energy to chemical energy in photosynthesis). Information Transactions: DNA controls cellular processes and gene expression, leading to specialized cell functions. Evolution: Explains the unity and diversity of life, with all organisms descending from a common ancestor 3.5 billion years ago. --- Chapter 2: The Nature of Molecules and the Properties of Water 2.1 The Nature of Atoms Atoms: The basic building blocks of matter. All matter is composed of atoms. Atomic Structure: ❖ Protons: Positively charged, located in the nucleus. ❖ Neutrons: Neutral particles, located in the nucleus. ❖ Electrons: Negatively charged, found in orbitals around the nucleus. .2 Elements Found in Living Systems 2 Atomic Number: The number ofprotonsin an atom, equals the number of electrons in a neutral atom. Elements are defined by their number of protons. Atomic Mass: ❖ Sum of protons and neutrons in an atom. ❖ Each proton and neutron has a mass of approximately 1 Dalton. Ions: Atom or molecule with a charge. ❖ Cations: More protons than electrons (positive charge). ❖ Anions: Fewer protons than electrons (negative charge). [ https://www.innovatechlabs.com/news room/2378/contaminant-analysis-cation -vs-anion/] Isotopes: ❖ Atoms of the same element with different numbers of neutrons. ❖ Radioactive isotopes: Unstable, emit radiation as they decay. 2.3 The Nature of Chemical Bonds hemical Bonds: Hold atoms together in molecules. C Ionic Bonds: Formed by the attraction of oppositely charged ions. - Sodium Chloride (NaCl). Covalent Bonds: Atoms share electrons to satisfy the octet rule. Strength depends on the number of shared electrons. [https://scienceinfo.com/covalent-vs-ionic-bond/] lectron Arrangement: E The behavior of an atom is determined by the arrangement of its electrons. ❖ Bohr Model: Electrons are in discrete orbits. ❖ Modern Model: Electrons exist in orbitals around the nucleus. [ https://ecampusontario.pressbooks.pub [ https://commons.wikimedia.org/wiki/Fi /prechemmods/chapter/modern-atomic- le:6_carbon_%28C%29_Bohr_model.pn theory/] g] .4 Water: A Vital Compound 2 Water is essential to life due to its unique properties. ❖ Polar Molecule: Uneven distribution of charge. ❖ Hydrogen Bonding: Attraction between the hydrogen atom in one water, molecule and the oxygen atom in another. .5 Properties of Water 2 Cohesion: Water molecules stick to each other (surface tension). Adhesion: Water molecules stick toothersurfaces. High Specific Heat: Water can absorb a lot of heat without a large temperature increase. High Heat of Vaporization: A lot of energy is required to convert liquid water to vapor. Solid Water (Ice) Floats: Ice is less dense than liquid water due to its hydrogen bonds. Solvent Properties: Water is a powerful solvent, dissolving many substances. 💡 Density of Water (Ice vs. Water)Ice is less dense than liquid water due to the hydrogen bonding between water molecules. In ice, the molecules are arranged in a r igid structure that takes up more space, making it less dense and allowing ice to float on water. .6 Acids and Bases 2 Acids: Substances that increase the hydrogen ion (H⁺) concentration in a solution. Bases: Substances that reduce the hydrogen ion concentration. pH Scale: Measures the acidity or alkalinity of a solution (0-14 scale). ❖ Acidic Solutions: pH less than 7. ❖ Basic Solutions: pH greater than 7. ❖ Neutral Solutions: pH of 7. [https://ibchem.com/IB16/08.31.htm] .1 Carbon: The Framework of Biological Molecules 3 Biological molecules are largely composed of carbon bonded to elements like O, N, C, P, and H. ❖ Carbon can form up to four covalent bonds. ❖ Hydrocarbons are molecules made solely of carbon and hydrogen, and they are nonpolar. CHO, CHON, CHONP: ❖ CHO: Found in carbohydrates and lipids (carbon, hydrogen, oxygen). ❖ CHON: Found in proteins (carbon, hydrogen, oxygen, nitrogen). ❖ CHONP: Found in nucleic acids like DNA and RNA (carbon, hydrogen, oxygen, nitrogen, phosphorus). 3.2 Carbohydrates: Energy Storage and Structural Molecules ❖ Monosaccharidesare simple sugars (glucose). ❖ Disaccharidesare two monosaccharides linked via dehydration synthesis (sucrose). ❖ Polysaccharidesare long chains of monosaccharides used for energy storage (starch, glycogen) or structural support (cellulose in plants, chitin in arthropods). 3.3 Nucleic Acids: Information Molecules ❖ Nucleotidesare the monomers of nucleic acids, composed of a sugar, phosphate, and nitrogenous base (adenine, guanine, thymine, cytosine, uracil). ❖ DNAis a double helix that stores genetic information, whileRNAis a single strand used for protein synthesis. NA and DNA Sugars: R DNAcontains the sugardeoxyribose, which lacks one oxygen atom compared to ribose. RNAcontains the sugarribose. The difference lies in their structure:deoxyribose has one less hydroxyl group (-OH) than ribose. 3.4 Proteins: Molecules with Diverse Structures and Functions* ❖ Proteins are polymers of amino acids, which form via peptide bonds. ❖ The structure of proteins has four levels: 1. Primary: The unique sequence of amino acids in a polypeptide chain. This sequence determines how the protein will fold. Amino acid sequence. . Secondary: The local folding of the polypeptide chain into alpha-helices or 2 beta-sheets, stabilized by hydrogen bonds. . Tertiary: The overall 3D structure of the protein, which is determined by 3 interactions between R groups (side chains) of amino acids. These include hydrogen bonds, disulfide bridges, hydrophobic interactions, and ionic bonds. . Quaternary: Some proteins consist of more than one polypeptide chain. The 4 quaternary structure is how these subunits arrange themselves relative to one another (hemoglobin has four subunits). Arrangement of multiple polypeptide subunits. ❖ Protein folding: Proteins fold into specific shapes to perform their functions, and folding errors can lead to diseases (cystic fibrosis). [ https://saylordotorg.github.io/text_the-basics-of-general-organic-and-biological-chem istry/s21-04-proteins.html] 3.5 Lipids: Hydrophobic Molecules ❖ Lipids include fats (triglycerides), phospholipids, steroids, and prostaglandins. ❖ Fats are used for energy storage, phospholipids form cell membranes, and steroids act as hormones. 💡 Saturated Lipids: These have nodouble bondsbetween carbon atoms in the fatty acid chains, which means the carbon atoms are“saturated” with hydrogen. Because of this, saturated fats are typically solid at room temperature (butter). Unsaturated Lipids: These containone or more double bondsin the fatty acid chains, which introduce kinks in the structure, preventing them from packing tightly. This makes them liquid at room temperature (olive oil).Double bondsin unsaturated fatsreduce the number of hydrogen atoms bonded to carbon atoms. esources: R Amoeba Sisters video on biomolecules: https://youtu.be/1Dx7LDwINLU Practice Questions! 1. Which of the following is true about lipids? A) Saturated fats have no double bonds in their fatty acid chains. B) Unsaturated fats are solid at room temperature. C) Saturated fats have kinks in their structure due to double bonds. D) Unsaturated fats have no double bonds and are typically solid. 💡 Saturated fats have no double bonds, which means their fatty acid chains are “saturated” with hydrogen. Unsaturated fats do have double bonds, which cause links and keep them liquid at room temperature. . Why does water have such a high surface tension? 2 A) Water molecules form hydrogen bonds with each other. B) Water molecules are nonpolar and stick together. C) Water forms covalent bonds with other water molecules. D) Water molecules avoid interactions with each other. 💡 Water moleculesform hydrogen bonds, making them “stick” together and gives water its high surface tension. This property allows insects to walk on water or causes droplets to form. . Which of the following is a result of hydrogen bonding in water? 3 A) Water is less dense as a liquid than as a solid. B) Water has a high heat capacity. C) Water molecules repel each other. D) Water has a low boiling point. 💡 Hydrogen bonding gives water ahigh heat capacity, which means it can absorb a lot of heat without a significant increase in temperature. This is why water takes longer to heat up than other substances. . How does a buffer maintain the pH of a solution? 4 A) It releases hydroxide ions to increase acidity. B) It absorbs or releases hydrogen ions (H+) as needed. C) It prevents any chemical reactions in the solution. D) It only neutralizes bases but not acids. 💡 Buffers maintain the pH of a solution by absorbing excess H+ ions when the solution becomes too acidic or releasing H+ ions when it becomes too basic. . What is true about a protein’s secondary structure? 5 A) It includes alpha-helices and beta-sheets formed by hydrogen bonds. B) It refers to the sequence of amino acids. C) It describes how multiple polypeptides interact. D) It includes the overall 3D shape of the protein. 💡 The secondary structure of proteins refers to local folding into alpha-helices and beta-sheets, which are stabilized by hydrogen bonds between the backbone of the amino acids.
