The 5 Themes of Geography: A Framework for Studying the World.
Unit 2 Themes And Tools For Studying Biology
-
Upload
olympus-high-school-jeff-taylor -
Category
Documents
-
view
901 -
download
0
description
Transcript of Unit 2 Themes And Tools For Studying Biology
1.1 The Study of Life
KEY CONCEPTTechnology continually changes the way biologists work.
1.1 The Study of Life
Imaging technologies provide new views of life.
• A microscope provides an enlarged image of an object.
stoma
– light microscopes (LM)
1.1 The Study of Life
stoma
– scanning electron microscopes (SEM)
Imaging technologies provide new views of life.
• A microscope provides an enlarged image of an object.
– light microscopes (LM)
1.1 The Study of Life
– transmission electron microscopes (TEM)
stoma
– scanning electron microscopes (SEM)
Imaging technologies provide new views of life.
• A microscope provides an enlarged image of an object.
– light microscopes (LM)
1.1 The Study of Life
• Imaging technology is used in medicine.
– X-ray images
1.1 The Study of Life
– magnetic resonance imaging (MRI)
• Imaging technology is used in medicine.
– X-ray images
1.1 The Study of Life
– functional MRI (fMRI)
– magnetic resonance imaging (MRI)
• Imaging technology is used in medicine.
– X-ray images
1.1 The Study of Life
Complex systems are modeled on computers.
• Computer models are used to study systems that cannot be studied directly.– heart attacks
– effect of medicines on the human body
– movement of water molecules into and out of a cell
– spread of a disease through a population
• Computer models are used when experiments are not safe, ethical, or practical.
Normal heartbeat
Heart attack
1.1 The Study of Life
The tools of molecular genetics give rise to new biological studies.
• A gene is a segment of DNA that stores genetic information.
1.1 The Study of Life
• Through our understanding of DNA, we can study genetics on a molecular level.
– molecular genetics– genomics
1.1 The Study of Life
KEY CONCEPTUnderstanding biology can help you make informed decisions.
1.1 The Study of Life
Your health and the health of the environment depend on your knowledge of biology.
• Knowledge of biology helps you understand your health.– food allergies– potential effects of obesity
1.1 The Study of Life
– cancer
• Knowledge of biology helps you understand your health.
– effects of alcohol, tobacco, and other drugs
brain
lungs
heart
liver
kidneys
– food allergies– potential effects of obesity
1.1 The Study of Life
• Knowledge of biology can help you understand environmental issues.– interactions in ecosystems
– biodiversity
– pollution
1.1 The Study of Life
Biotechnology offers great promise but also raises many issues.
• Biotechnology is the use and application of living things and biological processes.
1.1 The Study of Life
– DNA testing in medicine and forensics
• Biotechnology is the use and application of living things and biological processes.
– transgenic (genetically modified) crops– transgenic bacteria
1.1 The Study of Life
• Questions are raised about the use of biotechnology.
– spread of undesirable genes– decrease in biodiversity– ethical considerations
– safety of genetically modified crops
1.1 The Study of Life
Biology presents many unanswered questions.
• Over the past 50 years, biological knowledge has greatly increased.
1.1 The Study of Life
• There are still many questions to answer in biology.
– How are memories stored in the brain?
1.1 The Study of Life
• There are still many questions to answer in biology.
– How are memories stored in the brain?
surface proteins
lipid
envelope
nucleic acid capsid
– Does life exist on planets other than Earth?
– How do viruses mutate?
1.1 The Study of Life
KEY CONCEPTAll living things are based on atoms and their interactions.
1.1 The Study of Life
Living things consist of atoms of different elements.
• An atom is the smallest basic unit of matter.• An element is one type of atom.
H
O
Hydrogen atom (H)
Oxygen atom (O)
1.1 The Study of Life
– The nucleus has protons and neutrons.– Electrons are in energy levels outside nucleus.
Oxygen atom (O)
Nucleus:8 protons (+)8 neutrons
outermost energy level: 6 electrons (-)
inner energy level: 2 electrons (-)
• An atom has a nucleus and electrons.
1.1 The Study of Life
– water (H2O)
OHH
_
++
• A compound is made of atoms of different elements bonded together.
1.1 The Study of Life
– carbon dioxide (CO2)
• A compound is made of atoms of different elements bonded together.
– water (H2O)
1.1 The Study of Life
– many other carbon-based compounds in living things
• A compound is made of atoms of different elements bonded together.
– water (H2O)
– carbon dioxide (CO2)
1.1 The Study of Life
Ions form when atoms gain or lose electrons.
• An ion is an atom that has gained or lost one or more electrons.– positive ions– negative ions
• Ionic bonds form between oppositely charged ions.
Sodium atom (Na) Chlorine atom (CI) Sodium ion (Na+) Chloride ion (CI-)
Na loses anelectron to CI ionic bond
gained electron
1.1 The Study of Life
Atoms share pairs of electrons in covalent bonds.
• A covalent bond forms when atoms share a pair of electrons.
covalent bonds
Oxygen atom (O) Carbon atom (C) Oxygen atom (O)
Carbon dioxide (CO2 )
– multiple covalent bonds– diatomic molecules
1.1 The Study of Life
KEY CONCEPTWater’s unique properties allow life to exist on Earth.
1.1 The Study of Life
OHH
_
++
Life depends on hydrogen bonds in water.
• Water is a polar molecule.– Polar molecules have slightly charged regions.
– Nonpolar molecules do not have charged regions.– Hydrogen bonds form between slightly positive
hydrogen atoms and slightly negative atoms.
1.1 The Study of Life
• Hydrogen bonds are responsible for three important properties of water.– high specific heat– cohesion– adhesion
1.1 The Study of Life
Many compounds dissolve in water.
• A solution is formed when one substance dissolves in another.– A solution is a homogeneous mixture.– Solvents dissolve other substances.– Solutes dissolve in a solvent.
solution
1.1 The Study of Life
• “Like dissolves like.”
– Polar solvents dissolve polar solutes.– Nonpolar solvents dissolve nonpolar solutes.– Polar substances and nonpolar substances generally
remain separate.
1.1 The Study of Life
Some compounds form acids or bases.
• An acid releases a hydrogen ion when it dissolves in water.– high H+ concentration– pH less than 7
more acidic
stomach acid pH between 1 and 3
1.1 The Study of Life
• A base removes hydrogen ions from a solution.
– low H+ concentration– pH greater than 7
bile pH between 8 and 9
more basic
1.1 The Study of Life
• A neutral solution has a pH of 7.
pure water pH 7