Radioactive Isotopes and Atomic Structure

Course Information

• Course title: BIOL220 - General Biology
• Lecture date: 08/19
• Lecture 1 topic: Introduction to the course, The Chemistry of Life
• Credits: 4 credits
• Classes: Mondays and Thursdays, 11:00 to 12:15
• Laboratory: Wednesdays, 11:00 to 12:45
• Syllabus available on SAKAI Resources

Instructor Information

• Lecturer: Ms. Atoum Abdullah, Department of Biochemistry, School of Medicine
• Course Director and Lecturer: Dr. Paula Spiniello, Department of Biology, Ecology and Conservation, School of Arts and Science

Course Content

• The course covers life processes at molecular, cellular, organismal, population, community, and ecosystem levels.
• Topics include cell organization and communication, metabolism, cellular respiration, the cell cycle (meiosis and mitosis), genetics, evolution, origin of species, biology of viruses, bacteria, protists, plants, invertebrates, and vertebrates.
• The course also covers emergent properties of populations, communities, and ecosystems.
• Required textbook: Campbell Biology - 12th Edition

Course Grading

• Four exams (70% of final grade): Exam 1 (15%), Exam 2 (20%), Exam 3 (15%), Exam 4 (20%)
• One oral presentation (5% of final grade)
• Nine lab assignments and quizzes (25% of final grade): Assignments 1-3 and 6-9 (3% each), Assignments 4-5 (2% each)
• Exam format: Multiple choice (typically 40-50 questions)

Oral Presentation Requirements

• Groups of max 3 students
• Select a recent biology news article from a relevant media source.
• Prepare a 12-15 minute presentation and a 5-minute Q&A session
• Indicate group members to the lecturer by Wednesday 10 am.
• Submit the article title one week before the presentation.
• Use PowerPoint for presentation.
• Check resources for presentation instructions and rubrics.

Lab Information

• 9 lab sessions
• Students must read lab instructions before the corresponding session.
• Lab session instructions and assignments available on resources.
• Lab quizzes are available on SAKAI.
• Late submissions of lab assignments and quizzes will not be accepted. Students who do not submit before the deadline will receive zero points.
• Missed lab sessions result in a zero grade for the corresponding assignment and quiz.
• Lab sessions are mandatory and cannot be repeated.

Attendance Policy

• 100% attendance is expected.
• Attendance will be taken during all class and lab sessions.
• Students unable to attend an exam on the scheduled day must complete an online medical excuse form to take the exam at a different date.
• Three medical excuses in a single academic year will result in an automatic leave of absence (LOA).
• Oral presentations and lab sessions cannot be rescheduled.

Tips for Success

• Attend all lectures and lab sessions, actively participating in the class and lab sessions.
• Review each day's lecture material.
• Ask questions during lectures & lab sessions.
• Attend lecturer's office hours.
• Join a study group
• Be aware of deadlines for assignments, quizzes, and oral presentations.
• Practice presentations, actively preparing class material.

Learning Outcomes (Chemistry of Life)

• Describe the components of an atom
• Differentiate between an element, a molecule, and a compound
• List the elements of life
• Define an isotope
• Differentiate between covalent and non-covalent bonds
• Differentiate between polar and nonpolar covalent bonds
• Describe ionic, hydrogen, and van der Waals forces

Definitions

• Matter: Anything that takes up space and has mass. Matter exists in various forms (rocks, metals, oils, gases, living organisms). Living matter is mostly comprised of water (70-80%).
• Element: A substance that cannot be broken down by chemical reactions
• Compound: A substance consisting of two or more elements combined in a fixed ratio.

Natural Elements

• 92 naturally occurring elements.
• Some, like silver, sulfur, and mercury, occur naturally.
• Also, some radioactive elements are produced in labs or synthesized in labs.
• Essential elements: needed for life and reproduction. (approx. 20-25% of naturally occurring elements)
• Trace elements: in minute quantities (less than 0.01%), important to various body functions
• Examples of essential and trace elements that are commonly referenced were listed.

Atoms

• Each element consists of a unique atom.
• Element properties depend on the atom's structure.
• An atom is the smallest unit of an element that still retains the characteristics of that element.
• Atoms consist of a positive nucleus surrounded by negative electrons.

Subatomic Particles

• Atoms are made up of subatomic particles: neutrons, protons (positive charge), electrons (negative charge).
• Nucleus contains neutrons and protons
• Electrons orbit the nucleus in electron shells.

Atomic Number and Mass

• Atomic number: the number of protons in an atom's nucleus.
• An atom is electrically neutral because the number of protons equals the number of electrons.
• Atomic mass: the total number of protons and neutrons in an atom's nucleus.
• Most of an atom's mass is in its nucleus.
• Examples of specific isotopes of elements were listed in a table.

Isotopes

• Atoms of the same element that differ in the number of neutrons in their nuclei.
• Although isotopes differ slightly in mass, they generally behave the same in chemical reactions.
• Examples of isotopes of hydrogen, oxygen, carbon, nitrogen, and sodium.
• Radioactive isotopes: unstable isotopes that decay, emitting energy/radiation, used in dating fossils and various other applications (including medicine).

Electron Shells

• Electrons exist in different electron shells around the nucleus.
• Shells closer to the nucleus have lower energy.
• Each shell has a maximum capacity of electrons (First shell = 2, Second shell = 8, etc).

Valence Electrons

• Chemical behavior depends most on the number of valence electrons (the outermost shell of electrons).
• Valence electrons determine how atoms interact and form chemical bonds.

Chemical Bonds

• Atoms with incomplete valence shells interact with other atoms to complete their shells; this interaction results in chemical bonds.
• Types of chemical bonds include covalent (electrons are shared), ionic (electrons are transferred), hydrogen (weak attraction between a slightly positive hydrogen atom and a slightly negative atom - like oxygen).
• Van der Waals forces (weak attractions between molecules due to temporary electron shifts).