John Marshall LIFE SCIENCE
JMHS Biology Essential Concepts
ThESE PAGES HOLD THE TOOLS NEEDED TO SUCCEED IN BIOLOGY. HOWEVER, YOU WILL BE EXPECTED TO APPLY THESE TOOLS NOT JUST Carry them around.
John Marshall Biology Essential Concepts
I. History and Nature of Science
1. A law is a generalization on how some aspect of the natural world behaves under stated circumstances.
2. A theory is defined as a solid explanation of some aspect of the natural world that can incorporate facts, laws, and tested hypotheses.
3. The process of collecting data by taking pictures, writing down what you see, and even taking measurements of what you see is called an observation. When conclusions are drawn by using what you know and what you see, you have developed an inference.
4. The scientific method is a series of steps used to help scientists solve problems.(Identify the Problem, Hypothesis, Experiment, Observation (Data Analysis), and Conclusion)(PHEOC).
Scientists use peer review to discuss and validate results and check for bias.
· When a testable statement about the natural world has been created it is called a hypothesis. (educated guess)
· In a controlled experiment there are two test groups. There is an experimental
group and a control group.
· The control (the normal situation) is used to compare against the experimental data collected.
· The independent variable (manipulated variable) is what is changed in an experiment.
· The dependent variable (respondent variable) is what responds to what is changed in an experiment.
· Data collected in an experiment can come in two forms. The first type of data is called quantitative data (number) and revolves around exact objective measurements. These measurements use a measurement tool. The second type of data that can be collected is called qualitative data (description). This type of data is more subjective and less precise and is based on the scientist’s personal observations.
· Data needs to be viewed for sources of error.
5. The metric system is a measurement system that allows all scientists to use common units, which include but are not limited to meters, liters, and grams. The prefixes of the metric system include but are not limited to kilo, hecto, deka, base, deci, centi, and milli. (Other metric units include Celsius, Pascals, Sieverts and Newtons).
6. Graphing is a fundamental part of sharing information/data in a visual way. Pie, Chart,
Line, Bar, Histogram, Pictograph are all types of graphic organizers. Each graph is used for a
specific type of data illustration/interpretation and has its own format. Components of a
good graph are; title, labeled axis, a legend and appropriate units of measure.
7. Anything that causes an organism to react to their environment is called a stimulus (cause). When the organism actually reacts with its stimulus that reaction is termed a response (effect). This helps maintain homeostasis, which is how organisms maintain an internal environment which can be different from what is surrounding them.
8. Characteristics of Life is a set of criteria that allow scientists to determine if something should be considered living or not. They include the following set of criteria:
1) is made of cells 4) has ability to reproduce 7) maintains balance (homeostasis)
2) displays organization 5) has ability to respond to stimulus
3) grows and develops 6) has ability to use energy 8) has ability to adapt/evolve over time
Life Science (Ecology Emphasis)
9. Ecology is the study of the relationships of organisms (biotic) with one another and with the environment (abiotic).
10. The levels of organization for ecology are as follows
· Biosphere is the layer around Earth where all living things are located.
· Biome is a large area of land or water with similar climate, plants, and animals. The following are some examples of biomes: tropical rainforest, desert, grasslands, deciduous forest, and coniferous forest.
· Ecosystem is a community of living (biotic) organisms interacting with the non-living (abiotic) environment.
· Community is made of many different populations of organisms interacting with their environment.
· Populations are the total count of one species within a given area.
· Species is classified as a group of organisms that can successfully mate and produce fertile offspring.
11. Population growth is slowed when an organism runs out of space, food, water, or shelter.
Each of these is called a limiting factor.
12. The area in which an organism lives is called a habitat. An example of a habitat is a rabbit living in a log. The job of an organism within its habitat is called its niche. An example of a niche would be a bird eating seeds on the ground.
13. All organisms do not get their energy to live the same way. Organisms that make their own food are called autotrophs. Most organisms that make their own food use the process of photosynthesis. Organisms that can’t make their own food are considered heterotrophs.
14. Once limiting factors slow population growth, the population growth will eventually stop and become balanced. This occurs when the birth rate equals the mortality rate. The population is said to have reached its carrying capacity when this balance is reached. The population graph that shows carrying capacity is considered a logistical growth curve and is “S” shaped. Larger animals usually display this type of growth. Exponential growth occurs when populations double at a very fast rate. Organisms that display this type of growth are small and usually seasonal, such as bugs, bacteria, and small rodents. A graph that shows exponential growth is considered “J” Shape.
15. Energy is transferred in an ecosystem through a food chain starting with the sun releasing its energy to plants (producers). Then primary consumers (herbivores) eat the plants taking a small amount of the plants’ energy. Secondary consumers (carnivores and omnivores) then eat the primary consumers, gaining a small amount of their energy. When food chains overlap in an ecosystem, food webs are created.
16. Populations can change when members of its population leave the area; this is called emigration. New members can also enter a population, this is called immigration.
17. Symbiosis can occur when different species live together in a close association; this includes parasitism, commensalisms, mutualism, and predator/prey relationships.
· Parasitism is a relationship when one organism benefits (parasite) and the other is harmed (host).
· Commensalism is a relationship when one organism benefits and the other is not affected.
· Mutualism is a relationship when both organisms benefit.
· Predator/Prey is a relationship when one organism eats (predator) another organism (prey).
18. Biogeochemical Cycles (also known as matter + energy cycles) allow us to visualize how
nutrients are recycled within our environment. (ex. Water Cycle, Carbon Oxygen Cycle, Nitrogen Cycle, and the Phosphorous Cycle)
19. The risks associated with environmental factors and personal decisions need to be analyzed
to know the effect on personal and community health.
These can be labeled as either point or non point sources.
· Water quality
· Air quality
· Soil quality
II. Life Science (Emphasis Biochemistry)
20. The smallest particle of matter is the atom. The atom contains protons and
neutrons within the nucleus. The atom also has small particles called electrons that orbit the nucleus. Atoms that have the same number of protons and have different number of neutrons are called isotopes. When matter is made from the same atoms it is called an element. Common biological elements = C-carbon, O-oxygen, H-hydrogen, N-nitrogen,
P-phosphorous, S-sulfur
21. Compounds are created when more than one atom bond together. When compounds join together using covalent bonds they are called molecules. Chemical bonding occurs when atoms join together. When the atoms share electrons, covalent bonds are created. These are one of the strongest types of bonds. When atoms join together by transferring electrons to one another, they become attached due to ionic bonds. When atoms lose or gain electrons they are termed ions. A positive ion is called a cation, a negative ion is called an anion.
22. A hydrogen bond is a molecular force that is created when two polar molecules get close to one another, creating a very weak bond. This is a type of Van der Wals Force. Polar Molecules are slightly positive and negative on opposite sides of the molecule.
23. A macromolecule is an extremely large molecule. Macromolecules include proteins, lipids (fats), nucleic acids, and carbohydrates.
· Proteins are macromolecules that
are building blocks for our bodies.
They are created on the ribosomes
of our cells. They are built by
linking amino acids together.
· A lipid is a macromolecule that is
used in our body to store energy
and create hormones. Lipids are
built using two subunits. They are
fatty acids and glycerol.
· Nucleic acids are macromolecules
used in our body to create a genetic
blueprint to control the cells functions.
This material is made by linking
nucleotides together. Nucleic acids
help create D.N.A. and R.N.A..
· Carbohydrates are macromolecules
used to create quick sources of energy
for our bodies. A simple sugar called
glucose is the building block for this
macromolecule. Carbohydrates have
two forms: monosaccharides (simple sugars like glucose) and polysaccharides (complex carbohydrates built from simple sugars). Polysaccharides are found in animals as glycogen and are found in plants as starch.
24. When macromolecule subunits are joined together, a water molecule must be taken out. When this occurs it is called dehydration synthesis. When macromolecules are taken apart during digestion, a water molecule must be added to break them apart. This process is called hydrolysis.
25. Enzymes are proteins that speed up chemical reactions. (examples: polymerase, helicase, ligase, pepsin, and amylase). They do this by lowering the activation energy of a chemical reaction. Enzymes are not used or consumed during a reaction but only used to “help along” the reaction. The activation energy is the energy it takes to get a chemical reaction to start. Since enzymes aid in speeding up chemical reactions they are also called catalysts. Enzymes speed up chemical reactions by allowing substrates to attach to them, allowing them to react at a faster rate. When writing out a chemical equation there are two sides to the equation. The left side of the equation is called the reactants or the ingredients for the reaction to take place. The right side of the equation is called the products. This is what is produced from the reactants.
26. There are two different types of chemical reactions, endothermic and exothermic. Exothermic reactions are those that release energy as they occur. Endothermic reactions absorb energy as they occur.
27. Water is important to life for multiple reasons;
· Water exhibits cohesion and adhesion. When similar polar molecules are attracted, it is called cohesion. When molecules that are not similar attract, it is called adhesion.
· Water has a high specific heat (it takes a lot of energy to change the temperature water).
· Water is a good solvent; many organic compounds dissolve in water. Solvent is the name given to something doing the dissolving, Solute is the name given to something being dissolved.
· The pH scale, which stands for the potential of hydrogen ions, is a scale that measures the concentration of hydrogen ions (H+) or hydroxyl ions (OH-) in a solution. The scale goes from 0 to 14. The number seven is neutral, meaning the solution has the same number of hydrogen and hydroxyl ions. Water is considered to be neutral. The more acidic a solution is, the more hydrogen ions (H+) it has. The more basic a solution is, the less hydrogen ions (H+) it has.
III. Life Science (Cell Biology Emphasis)
28. The cell theory, which was developed by Rudolph Virchow, Matthias Schleiden and Theodor
Schwann, states the following:
· all living things are made up of one or more cells
· cells are the basic units of life
· all cells can only come from other living cells
29. A prokaryote is the simplest of all living cells. The prokaryote contains no nucleus within its cell. Its only genetic information is a circular strand of DNA. Bacteria make up all of the prokaryotes. The prokaryotes can be broken up into two kingdoms: the archeobacteria and the eubacteria. A eukaryote is a more complex cell that has many organelles which include a true nucleus. Eukaryotic cells help create four different kingdoms, the protist, fungi, plant, and animal kingdoms.
30. Cells contain small organ like structures that carry out many important functions for the cell. These small structures are called organelles. The following are some of the more important organelles in a eukaryote:
· The nucleus is the control center of the cell. The nucleus is surrounded by a nuclear membrane that protects the DNA and nucleolus that is with the nucleus. This organelle is found in all eukaryotes.
· The cell membrane surrounds all cells. It allows material to be passed in and out of the cell. It is made by a double layer of phospholipids with protein channels extending through both layers..
· The cytoplasm is a clear jelly like fluid that is found within all cells. This liquid contains all the organelles found within the cell, but also allows material to pass through it.
· The cell wall is a stiff protective coat found on both eukaryotic and prokaryotic
· cells. The cell wall can be made of things like chitin and cellulose. The cell wall is not present in animal cells.
· The mitochondria is an organelle that creates energy for both animal and plant cells in the form of ATP. The mitochondria is the site where respiration occurs.
· The endoplasmic reticulum is an organelle that is made of networked canals. This organelle’s main job is to transport proteins to the Golgi Body.
· Proteins are built on an organelle that is called a ribosome. Ribosomes can be found in prokaryotes and eukaryotes. They are made primarily out of ribosomal RNA.
· Golgi body looks like a bunch of flattened sacs in a cell. The Golgi body’s main job is to package and distribute molecules (proteins) that are created in the cell.