Bio 1A Lect 1 - Professor Jennifer Doudna Office Hours: TWF...

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Unformatted text preview: Professor Jennifer Doudna Office Hours: TWF 9 - 10am Room: 708A Stanley Hall Exam Information Exam 1 (2/22/10): 100 pts Exam 2 (04/02/10): 100 pts Final (05/10/10): 300pts Total Points: 500 pts Study Tip: When studying, focus on notes and what is discussed during lecture. Readings are helpful but you are not required to know exactly what is in the Campbell book. Biology 1A Lecture 1 1 Pimentel Spring 2010 01/20/10 8:00am Introduc)on to Biology h" Bio 1A Spring 2010 Part I: Prof. Jennifer Doudna In order to succeed in this class, you must have a basic understanding of chemistry. Refer to chapters 2 and 3 in the Campbell book (7th or 8th edition) for a review. BIOLOGY, 8th edi)on •  Reading: pp. 4‐5, 30‐32, 46‐48 •  Lecture outline: –  Levels of biological organizaMon –  The chemistry of life –  ProperMes of water are essenMal in biology Overview: Inquiring About the World of Life •  Evolu)on is the process of change that has transformed life on Earth •  Biology is the scienMfic study of life •  Biologists ask quesMons such as: This is an incredibly broad subject and has many facets and parts. –  How does a single cell develop into an organism? –  How does the human brain work? –  How do living things interact in communiMes? underlying theme: How evolution is the underlying theme of biology Evolu)on, the Overarching Theme of Biology •  EvoluMon makes sense of everything we know about living organisms •  Organisms living on Earth are modified descendents of common ancestors - organisms are related to each other in some sort of way i. genomic sequencing allows us to see how genomes from different species are similar all organisms are related to each other For fun and learning, see: **NOVA 3‐part series: Becoming Human** Downloadable from iTunes The biological hierarchy The biosphere Cells 10 µm Organs and organ systems Cell Ecosystems Organelles Communi)es 1 µm Tissues Popula)ons Organisms Atoms 50 µm Molecules The study of life can be divided into different levels of biological organizaMon Fig. 1‐4 Emergent Proper)es •  Emergent proper)es result from the arrangement and interacMon of parts within a system - These are features or properties on an organism that arise from the organism's interactions with its environment and how the organism is arranged or composed out of compounds •  Emergent properMes characterize non‐biological enMMes as well –  For example, a funcMoning bicycle emerges only when all of the necessary parts connect in the correct way Systems Biology •  A system is a combinaMon of components that funcMon together •  Systems biology constructs models for the dynamic behavior of whole biological systems •  The systems approach poses quesMons such as: –  How does a drug for blood pressure affect other organs? –  How does increasing CO2 alter the biosphere? Chapter 2 Overview: Chemical Founda)ons of Life •  Biology is a mulMdisciplinary science - In order to fully understand biology, one needs to know information from other subjects, such as anthropology, geography, chemistry, etc. •  Living organisms are subject to basic laws of physics and chemistry Concept 2.1: MaSer consists of chemical elements in pure form and in combina)ons called compounds •  Organisms are composed of maSer •  Ma"er is anything that takes up space and has mass Elements and Compounds •  Ma"er is made up of elements •  An element is a substance that cannot be broken down to other substances by chemical reacMons •  A compound is a substance consisMng of two or more elements in a fixed raMo •  A compound has characterisMcs different from those of its elements Compound Compound Is oxygen an element or a compound? What about iron? Water? Carbon dioxide? Element Element Elements Compound Sodium Chlorine Sodium chloride Fig. 2‐3 Essen)al Elements of Life Only about eight elements make up biological systems: carbon, hydrogen, oxygen, nitrogen, calcium, phosphorus, potassium, and sulfur •  About 25 of the 92 elements are essenMal to life •  Carbon, hydrogen, oxygen, and nitrogen make up 96% of living ma"er Most biological compounds are •  made from these Most of the remaining 4% consists of calcium, phosphorus, elements potassium, and sulfur •  Trace elements are those required by an organism in minute quanMMes These elements are critical for life, but only in extremely small amounts Table 2‐1 Effects of Deficiencies of Essen)al Elements Corn plant growing in Nitrogen-rich soil is darker green and taller Corn plant growing in Nitrogen-poor soil is shorter and yellowish green (a) Nitrogen deficiency (b) Iodine deficiency: Goiter! Deficiency of trace element iodine, a critical component of thyroid hormone, leads to swelling of the hormone to compensate for lack Fig. 2‐4 Water: The Molecule That Supports All of Life •  Water is the biological medium on Earth •  All living organisms require water more than any other substance aqueous environment •  Most cells are surrounded by water, and cells themselves are about 70–95% water •  The abundance of water is the main reason the Earth is habitable Earth is mostly water, allowing life to survive here Fig. 3-1 The polarity of water molecules results in hydrogen bonding •  The water molecule is a polar molecule: The opposite ends have opposite charges •  Polarity allows water molecules to form hydrogen bonds with each other Special bonds that are similar to covalent bonds, but between the electropositive hydrogen and electronegative oxygen O H H Hydrogen bonds result in a relatively long network of interactions and chains Hydrogen bonds are strong because they occur in relatively large amounts δ – δ + Hydrogen bond Hydrogen bonds contribute greatly to the stability of proteins H —— δ + δ – δ – δ + O H δ + δ – Fig. 3-2 Four proper)es of water contribute to Earth’s fitness for life •  Four of water’s properties that facilitate an environment for life are: –  Cohesive behavior –  Ability to moderate temperature –  Expansion upon freezing –  Versatility as a solvent Cohesion and Adhesion •  Collectively, hydrogen bonds hold water molecules together, a phenomenon called cohesion •  Cohesion helps the transport of water against gravity in plants •  Adhesion is an attraction between different substances, for example, between water and plant cell walls hydrogen bonding occurs not only Due to hydrogen bonding between water cells, but between water and other cells Units of temperature and energy •  The Celsius scale is a measure of temperature using Celsius degrees (°C) •  A calorie (cal) is the amount of heat required to raise the temperature of 1 g of water by 1°C •  The “calories” on food packages are actually kilocalories (kcal), where 1 kcal = 1,000 cal •  The joule (J) is another unit of energy where 1 J = 0.239 cal, or 1 cal = 4.184 J Water helps to shield or buffer extreme changes in temperature, ie lakes and oceans ...
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