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Biology Study Guide
Introduction
This study guide was devised to enable students to review the basic biological concepts that they may need in preparing for the Biology Exit Assessment. It is not intended to be a comprehensive course in biology. The study of biology as in all sciences contains investigations and activities that are integral parts of the courses. As students and teacher use this guide they should be ever mindful of basic scientific principals that require investigation and discovery.
Basic Scientific Principles
Scientific Method
Observe Define Problem Formulate Hypotheses (Always a statement. Never a question) Test Hypothesis (possible explanation based on research and prior (knowledge) Collect, Organize, and Analyze Data (facts collected during an Investigation. Could be measurements or other observations) Draw Conclusions Report Findings
There are variations on this method that all scientists use.
Observations lead to questions. These questions are often how a problem is defined. Example
Problem: Is growth of spinach plants influenced by light wavelength? Hypothesis: Spinach growth will be influenced by different wavelengths of light. Test: Spinach plants will be grown in the following way:
Experimental Group 100 plants grown in red light 100 plants grown in orange light 100 plants grown in yellow light 100 plants grown in green light 100 plants grown in blue 100 plants grown in indigo light 100 plants grown in violet light
Control Group
Try These:
1. Identify the two main parts on this diagram of an atom and identify the _three subatomic particles:
- If an example of a chemical property of iron is its ability to react with_ oxygen, what is an example of a chemical property of oxygen?
Elements
The universe is composed of approximately 100 types of atoms. Each type of atom is referred to as an element. Carbon (C) and oxygen (O) are examples of elements.
In nature most elements combine with other elements to form chemical compounds. Carbon dioxide (CO 2 ) is an example of a chemical compound.
Try These:
_1. Which of the following is an element and which is a compound? a) S b) SO 3 c) ZnCl 2 d) Na
- If the universe is only composed of about 100 types of atoms, explain why there are millions of different chemical substances._
Chemical Bonding
Atoms form compounds through interactions between their electron clouds in a process called chemical bonding.
The two main types of chemical bonding are ionic bonding and covalent bonding. In both cases atoms join each other to become new substances, but do so in different ways.
In ionic bonding atoms lose or gain electrons to become positively or negatively charged particles called ions. These ions then are attracted to each other because of the opposite charges, forming chemical compounds with new properties. Many ionic compounds exist as crystals that can break apart into separate ions when dissolved in water. An example of a common substance formed by ionic bonding is sodium chloride (NaCl).
In covalent bonding atoms share electrons between them. In effect their electron clouds become fused together forming a molecule with new properties. An example of a covalent molecule is carbon dioxide (CO 2 ). In some cases atoms of the same types can covalently bond together to form molecules. Oxygen atoms (O) bond to form oxygen molecules (O 2 ) or ozone molecules (O 3 ).
Try These:
_1. Compare and contrast an ionic and covalent bond.
- What type of bonding is depicted by this diagram? Explain._
Water
Water is extremely important to life on earth for many reasons. Many different substances can dissolve in it and therefore it is a substance in which the chemical reactions supporting life can occur. It is an excellent absorber of heat energy and allows living cells to remain at stable temperatures despite temperature changes outside the cell. It also moderates the Earth’s temperature as large bodies of water absorb or release energy.
Water molecules consist of two hydrogen atoms covalently bonded to an oxygen atom.
Water has the formula H 2 O and the molecular structure depicted in the diagram at the right.
Water electrons are not shared evenly. This is because oxygen has an extraordinarily large attraction for the shared electron and hydrogen has a fairly weak attraction for the shared electrons. Because of this uneven sharing, the oxygen atom has a partial negative charge and the hydrogen atoms have a partial positive charge giving the water molecule a positive side and a negative
- nucleus
- electron cloud
- chemical properties
- element
- chemical compound
- chemical bonding
- ionic bonding
- ion
- covalent bonding
- molecule
- water molecules
- formula
- polar covalent
- nonpolar covalent
- hydrogen bond
- cohesive property 2. The Chemistry of Life
The Elements of Life
Most living things are composed primarily of only six elements: carbon (C), hydrogen (H), oxygen (O), Nitrogen (N), sulfur (S), and Phosphorus (P).
Of these elements, carbon is important because it can form millions of large, complex molecules essential to life. These large complex molecules are referred to as macromolecules.
Organic Compounds in Living Things
Four main groups of organic (carbon-based) compounds are carbohydrates, lipids, proteins, and nucleic acids.
Carbohydrates are composed primarily of carbon, hydrogen and oxygen and used primarily by living things as a source of energy and for structure.
The simplest carbohydrates are sugars called monosaccharides. An example of a monosaccharide is the sugar glucose C 6 H 12 O 6.
Monosaccharides can bond together to form larger carbohydrates called polysaccharides. An example of a polysaccharide is starch as is found in potatoes or pasta.
Monosaccharides are used directly by living cells to produce energy. Since they can be broken down into monosaccharides, polysaccharides allow living things to store energy for energy for future use.
Some large polysaccharides can be used by living things for structure. The cellulose making up wood is an example of a structural polysaccharide.
The lipids are a class of organic compounds made up of carbon, hydrogen and oxygen and will not dissolve in water. Examples of lipids are fats, waxes, and sterols.
Lipids are used by living things primarily for energy storage since they contain even more energy than the carbohydrates.
Lipids also form an important part of cellular membranes and are also used by living things when waterproof coatings (such as the waxy coatings on some leaves) are needed.
Fats are a type of lipid composed of fatty acid molecules bonded to glycerol molecules and may be saturated (such as the solid fats found in beef, butter, and cheese) or unsaturated (such as the oils found in olives, nuts, and fish). Proteins are compounds made of carbon, hydrogen, oxygen and nitrogen and serve as structural and regulatory substances. Proteins are composed of smaller molecular units called amino acids.
The collagen that makes up tendons and cartilage is an example of a structural protein.
Enzymes are proteins that increase the rate of a chemical reaction. Most of the chemical reactions involved with the metabolism of living things would occur so slowly without enzymes that life would be impossible.
Each enzyme acts on a particular target molecule or substrate. The enzyme has a region known as the active site that is able to chemically bond with the substrate molecule and allow chemical changes to occur in that substrate much faster than without the enzyme.
An example of enzyme action would be enzymes in saliva breaking down the starch from bread as it is being chewed, changing the starch into monosaccharides.
Nucleic acids are macromolecules made of carbon, hydrogen, oxygen, nitrogen and phosphorus. They store and transmit hereditary information in living things.
The two types of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
Try These:
1. Give an example of a carbohydrate, a lipid, a protein and a nucleic acid _and discuss the function of each.
- Is the chemical structure below a fragment of a protein, nucleic acid, or_ _carbohydrate? How do you know?
- Describe the process by which an enzyme speeds up a chemical reaction.
- Label this diagram of the process in #3 above._
Vocabulary List for 2. The Chemistry of Life
- macromolecules
- C H O N S P
- organic compound
- monosaccharide
- polysaccharide
- lipid
- saturated fat
- unsaturated fat
- protein
- amino acid
- enzyme
- substrate
- nucleic acid
- DNA
- RNA
The Nature of Matter Web Resources
http://corrosion.ksc.nasa.gov/electrochem_nature.htm
http://www.biology.arizona.edu/biochemistry/tutorials/chemistry/page3.html
http://www.infoplease.com/cig/biology/water.html
3. Cell Biology
The characteristics of life state that an organism must be made of cells, able to reproduce, grow, develop have organization, use energy/ATP, evolve, have heredity, adapt to their environment, and maintain homeostasis (stable internal environment).
There are 3 parts to the cell theory: all living things are made of cells (smallest units of life), cells are the basic units of structure and function in an organism (anything living) and existing cells produce new cells.
An organism is considered to be alive even if it is just made of one cell. This organism would be said to be unicellular.
Microscopes
ribosomes which make proteins, the endoplasmic reticulum and golgi apparatus which direct materials through the cell, the centrioles which aid in the process of mitosis (cell division), the vacuoles which stores water and waste and also takes up about 80% of space in a plant cell, the chloroplasts help make energy/ATP in plant cells through the process of photosynthesis and contains a green pigment called chlorophyll , and a cell wall which provides an extra barrier in plant cells.
Try This:
Given data you should be able to determine whether a cell being described is eukaryotic or prokaryotic. Furthermore you should be able to tell whether it is a plant or animal cell.
1. You are on a class trip at the Liberty Science Center and one of the attractions is viewing cells under the microscope. You look into the microscope and see a cell with a clearly defined nucleus and a large central vacuole. What can you conclude about this cell?
Vocabulary List for 3. Cell Biology
- Homeostasis
- Cells
- Organism
- Unicellular
- Microscope
- Magnification
- Resolution
- Prokaryotes
- Eukaryotes
- Cytoplasm
- Organelles
- Nucleus
- Mitochondria
- Ribosome
- Endoplasmic Reticulum
- Golgi Apparatus
- Centrioles
- Mitosis
- Vacuoles
- Chloroplast
- Photosynthesis
- Chlorophyll
- Cell Wall
Ch. 3 Cell Biology Web Resources
http://images.google.com/imgres?imgurl=http://evolution.berkeley.edu/evosite/lin es/images/cells.gif&imgrefurl=http://evolution.berkeley.edu/evosite/lines/IIDmolec ular.shtml&h=275&w=511&sz=18&hl=en&start=3&tbnid=IXWsNpEjFuwJjM:&tbn h=70&tbnw=131&prev=/images%3Fq%3Danimal%2Band%2Bplant%2Bcells% gbv%3D2%26svnum%3D10%26hl%3Den
http://images.google.com/imgres?imgurl=http://www.biologycorner.com/resource s/cell.gif&imgrefurl=http://www.biologycorner.com/bio1/cell.html&h=311&w=429& sz=27&hl=en&start=9&tbnid=0yE2Vhz3ielzaM:&tbnh=91&tbnw=126&prev=/imag es%3Fq%3Danimal%2Band%2Bplant%2Bcells%26gbv%3D2%26svnum%3D %26hl%3Den
http://images.google.com/imgres?imgurl=http://www.biologycorner.com/resource s/MICRO- labeled.gif&imgrefurl=http://sps.k12.ar.us/massengale/parts_of_a_compound_lig ht_micros.htm&h=441&w=472&sz=44&hl=en&start=3&tbnid=IBLNc48P3MC9rM: &tbnh=121&tbnw=129&prev=/images%3Fq%3Dcompound%2Blight%2Bmicrosc ope%26gbv%3D2%26svnum%3D10%26hl%3Den
4. Cell Boundaries
Cells have a cell membrane that regulates what enters and leaves a cell, and also provides protection and support.
The cell membrane is said to be semi-permeable -allows some things in and out of the cell.
The cell membrane can also be referred to as a lipid bilayer (two distinct layers). Each layer is made of phospholipids. Each phospholipid is comprised of a hydrophilic ( water attracting) head and a hydrophobic (water repeling) tail.
The cell membrane is not a rigid structure, rather it behaves more like a fluid than a solid, that is why it is often referred to as a fluid mosaic model.
Types of Movement Across a Membrane
Diffusion is the movement of molecules from high concentration to low concentration and Osmosis is the diffusion of water molecules from high concentration to low concentration are the two main ways for molecules to cross the cell membrane both of which do not require the use of the cells energy/ATP. Molecules can freely move across the membrane until equilibrium is reached. This is when the concentration of substances are the same on both sides of the membrane.
- Hydrophobic
- Fluid mosaic model
- Diffusion
- Osmosis
- Equilibrium
- Active Transport
- Concentration Gradient
- Hypotonic
- Hypertonic
- Isotonic
Ch.4 Cell boundaries Web Resources
http://images.google.com/imgres?imgurl=http://www.biologycorner.com/resource s/cell_membrane.jpg&imgrefurl=http://www.biologycorner.com/bio3/notes- cell_membrane.html&h=294&w=600&sz=24&hl=en&start=37&tbnid=OLP9DbWa b7EclM:&tbnh=66&tbnw=135&prev=/images%3Fq%3Dcell%2Bmembrane%26st art%3D20%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa %3DN
5. Cellular Organization
Multicellular organisms have two or more cells. Organisms develop in different ways to perform particular functions within the organism, which is called differentiation.
The four levels of organization in multicellular organisms are: cells, tissues (groups of similar cells that carry out a common function), organs (several types of body tissues that together perform a function) and organ system (a group of organs that interact to perform a set of related tasks).
Try This:
- Name a cell, tissue, organ and an organ system in the human body.
Vocabulary List for 5. Cellular Organization
- Multicellular
- Differentiation
- Tissues
- Organs
- Organ System
Ch 5. Cellular Organization Web Resources
http://images.google.com/imgres?imgurl=http://images.main.uab.edu/healthsys/ei _0132.gif&imgrefurl=http://www.health.uab.edu/default.aspx%3Fpid%3D15743% 26print%3Dyes&h=363&w=380&sz=20&hl=en&start=3&tbnid=NxSYHvDiij7W1M: &tbnh=117&tbnw=123&prev=/images%3Fq%3Dorgan%2Bsystems%26gbv%3D 2%26svnum%3D10%26hl%3Den
6. Energy and Life
Photosynthesis
All things need energy to live. Energy starts with the sun. Plants use the sun’s energy in photosynthesis – the process by which plants and some microorganisms use light energy to produce food.
(http://students.salisbury.edu/~ak09850/images/photosynthesisBASIC.jpg)
Chloroplasts are organelles (cell parts) that convert light energy into chemical energy in chemical bonds. Chlorophyll is a green pigment in the chloroplast that absorbs the light.
Equation for photosynthesis:
effect photosynthesize. Explain how you would test this hypothesis? What would you use as a control?
Cellular Respiration
In cellular respiration plants and animals break down molecules (like carbohydrates) to release and store energy.
Different organisms use different methods of respiration. The first step for all organisms is glycolysis. It occurs in the cytoplasm. In glycolysis glucose is broken down.
If no oxygen is present the next step is fermentation in which pyruvic acid is broken down. Yeast uses fermentation, as do some other organisms, when oxygen is not present. Fermentation is an example of anaerobic respiration, meaning no oxygen is present.
When oxygen is present ( aerobic respiration) much more energy is produced. Oxidative respiration occurs in the mitochondria and more ATP is made.
The equation for respiration is very similar to photosynthesis reversed:
C 6 H 12 O^6 + 6O^2 Æ^ 6CO^2 + 6H 2 O + ATP(energy)
The end products of photosynthesis are the starting products of respiration. The end products of respiration are the starting products of photosynthesis. This is one example of interdependence, living things depending on each other to survive.
During both processes chemicals are being broken down, electrons are being moved, and energy is being used and stored to maintain life.
In addition to energy, chemicals necessary for building, repairing and maintaining living things are being broken down and built up. These chemicals and the energy they contain are cycled from organism to organism in food webs. Plants (photosynthetic organisms) will always be the producers of energy because of their ability to convert solar energy to food. Herbivores (plant eaters) will be the next level of energy. Consumers such as carnivores (meat eaters) and omnivores (plant and meat eaters) will follow. Even dead organisms are recycled by decomposers (break down wastes).
Try These:
1. When you exercise you use oxygen very quickly. Sometimes your muscles use oxygen and can not produce energy fast enough for your _body. But your muscles still work. How can they still work?
- How could the destruction of the rainforests and ocean pollution_ _(destroying algae) impact human respiratory disorders?
- Hypothesize how providing O 2 to long distance runners might influence_ their performance. Explain how you could test this hypothesis?
Vocabulary List for 6. Energy and Life
- Photosynthesis
- Chloroplasts
- Chlorophyll
- Stomata
- ATP
- Carbohydrates
- Cellular Respiration
- Glycolysis
- Fermentation
- Anaerobic
- Aerobic
- Producers
- Herbivores
- Carnivores
- Omnivores
- Decomposers
Energy and Life Web Resources
http://micro.magnet.fsu.edu/primer/java/photosynthesis/
http://www.homestead-farm.net/KidsLinks/Photosynthesis.html
http://defiant.corban.edu/gtipton/sc-134/inspir-photosynth/index.html
http://staff.jccc.net/pdecell/cellresp/respoverview.html
http://bioweb.cs.earlham.edu/9-12/cellularrespiration/
http://trc.ucdavis.edu/biosci10v/bis10v/week3/06aerobicrespirintro.html
