Biology Exam 1 Study Guide
Biology Exam 1 Study Guide BIO-101-105
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Adriana Shania Proctor
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This 22 page Study Guide was uploaded by Adriana Proctor on Wednesday September 21, 2016. The Study Guide belongs to BIO-101-105 at Chesapeake College taught by Doctor Hatkoff in Fall 2016. Since its upload, it has received 11 views. For similar materials see Fundamentals of Biology I in Science at Chesapeake College.
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Date Created: 09/21/16
Biology Exam 1 *Study Guide Section 1 BiologyIs the study of life. It is the study of organisms that are divided into the following categories: ● Morphology ● Physiology ● Anatomy ● Behavior ● Origin ● Distribution Evolution is the process of change that has transformed life on Earth. An example is the beach mouse, who has evolved to blend in with its surroundings. Unifying themes that biology reveals help organize information, and they are as follows: ● Organization ● Information ● Energy and Matter ● Interactions ● Evolution Life can be studied at different levels, from molecules to the entire living planet of Earth. There are approximately 10 different levels: 1. The Biosphere 2. Ecosystems 3. Communities 4. Populations 5. Organisms 6. Organs 7. Tissues 8. Cells 9. Organelles 10. Molecules Reductionism is the practice of studying and describing something complex and breaking it down to something simple. An example of this is the study of DNA molecular structure to understand the chamical basis of various things. Levels of Organization Atoms→Molecule or Compound→Organelle→Cell→Tissue→Organ→Organ System→Organism ● Scientists attempt to understand how natural phenomena work using processes that include making observations, forming logical hypotheses, and testing them. The process is repetitive and can never be conclusively proven to be true due to the inability to test all alternatives. DataR ecorded Data. HypothesisA tentative answer to a well framed question. Also a step in the Scientific Method. Deductive ReasoningIs a logical process in which a conclusion is based on the concordance of multiple premises that are generally assumed to be true. Inductive ReasoningIs a logical process in which multiple premises, all believed true or found true most of the time, are combined to obtain a specific conclusion. Not every scientific inquiry can be solved with the scientific method. Sometimes scientists have to redirect their research when they realize they have been asking the wrong questions. Experimental Variables and Controls ● A controlled experiment compares an experiment group with a control group. ● The factor that is manipulated and the effect of the factor are both experimental variables. ● The independent variable is determined by the researcher. ● The dependent variable is measured by the experiment. A scientific theory is much more in scope than a hypothesis. A theory is supported by more evidence. Scientists are able to reject or modify theories when new research methods produce results that don’t fit. Over the last few decades science has seen the inclusion of women, minorities, and people from different countries, all reflecting different cultural standards and behaviors. The Cell Section 2 The cell is the lowest level of biological organization that can perform all of the activities required for life. The two main forms of a cell are prokaryotic and eukaryotic. Then there are the Bacteria and Archaea. 1. EukaryotaPlants, animals, fungi, flagellates, basal protists, chromists, etc. 2. BacteriaCyanobacteria, heterotrophic bacteria. 3. ArchaeaHalophiles, thermophiles. Bacteria and Archaea are prokaryotes, and Eukaryota happens to be consisting of eukaryotes. A eukaryotic cell contains membraneenclosed organelles, including a DNAcontaining nucleus. Large and complex, its cytoplasm contains organelles. Each organelle carries out a specific function. A prokaryotic cell however, is smaller and is simpler than a eukaryotic cell. Similarities: They are both bound by a plasma membrane They both have cytosol Contain chromosomes Have ribosomes that carry out protein synthesis Differences: Eukaryotic cells hold their DNA in the nucleus Prokaryotic cells hold DNA in their nucleoid. Organelle Plant Animal Vacuole Yes Yes Chloroplast Yes No Ribosome Yes Yes Nucleus Yes Yes Mitochondria Yes Yes ER Yes Yes Cell Wall Yes No DNA Yes Yes Golgi Apparatus(Golgi Yes Yes Body) Organelle Plant Animal Bacteria Function Vacuole Yes Yes No Storage Chloroplast Yes No No Photosynthesis Ribosome Yes Yes Yes Protein Nucleus Yes Yes No House of DNA Mitochondria Yes Yes No Cell Respiration(mak es ATP) ER Yes Yes No Protein/lipid synthesis Cell Wall Yes No Yes(periplasmic Protection and space then cell structure wall) DNA Yes Yes No Blueprint for everything Golgi Yes Yes No Shipping Apparatus(Golgi proteins out Body) *Bacteria Cell The Eukaryotic Cell The nucleus contains most of the genes in a eukaryotic cell. The rest of the genes are in the mitochondria and chloroplast. The nucleus is enclosed in the nuclear envelope, and its pores allow for passage of materials into and out of the nucleus. Chromosomes in the nucleus carry out genetic information. The ribosomal RNA(rRNA) are synthesized there. The protein subunits that comprise ribosomes are imported in to build the said ribosome. Ribosomes, in an eukaryotic cell, can exist in two places: ● Free ones are in the cytosol. ● Bound ribosomes are attached to the outside of the endoplasmic reticulum. Ribosome are made of rRNA and Protein! Nucleus ● Contains the cell’s DNA and controls its activities by directing protein synthesis by making mRNA(messenger RNA). ● DNA associated with proteins is called chromosomes. ● mRNA is a family of RNA molecules that have genetic information from DNA to the ribosome. The Endomembrane System Section 3 Endomembrane system Includes the following: ● Nuclear envelope ● Endoplasmic reticulum ● Golgi Apparatus(Golgi Body) ● Lysosomes ● Various kinds of vesicles ● Vacuoles ● Plasma membrane The membrane can either make direct contact with another, or by the moving of membrane segments as vesicles. The endoplasmic reticulum(ER) is a network of membranes in a cell. They contain a network of tubules and sacs called cisternae. There are two types of ER: ● Smooth ER, which has no ribosomes. They synthesize lipids oils proteins steroids They also metabolize carbohydrates, detoxification of drugs/poisons, and store calcium ions. ● Rough ER, which is studded with ribosomes. The proteins that are secreted are synthesized and then threaded into the ER lumen. It distributes transport vesicles and is abundant in cells that secrete protein. ● Accounts for more than half the total of membrane in the eukaryotic cells. ● It is the largest component of the endomembrane system. The Golgi Apparatus receives, sorts, ships, and manufactures proteins. The Golgi can be described as a stack of flapjacks that has two sides, the cis and trans face(act as the receiving and shipping departments). It also modifies products of the ER, manufactures certain macromolecues. Finally, they sort and package materials into transport vesicles. A lysosome is a membranous sac of hydrolytic enzymes that the animal cells use to digest macromolecules. Lysosomal enzymes work in an acidic environment as they carry out a variety of digestion in the cells. They, in other words are a membraneenclosed sac of digestive enzymes made by rough ER processed in the Golgi apparatus. They fuse with food vacuoles and digest said food as well as damaged organelles. They aso destroy bacteria engulfed by white blood cells. Vacuoles perform different functions in different cells. Food vacuoles are resulted from digesting nutrients. Contractile vacuoles pump out unnecessary water from the cells. In plants, the vacuoles can hold organic compounds and pigments. They also have a central vacuole, which acts as a repository for ions. Central vacuoles can become large and push cytoplasm towards a thin area. ● Vacuole are large vesicles that have a variety of functions. ● Plant vacuoles digestive functions contain pigments and poisons that protect the plants. Mitochondria and Chloroplast ● Mitochondria are the sites of cellular respiration. They are not a part of the endomembrane system. They have a double membrane as well as contain proteins created by free ribosomes along with their own DNA. ● Chloroplasts are the site of photosynthesis Endosymbiotic Theory The endosymbiotic theory is that an early ancestor of eukaryotic cells are engulfed by a prokaryotic cell. This formed an endosymbiotic relationship with its host. The host cell and endosymbiont merged into a single organism, which is a eukaryotic cell with a mitochondrion. Organisms Interact with Other Organisms and the Physical Environment Every organism interacts with other organisms and with physical factors in its environment. An example of this is a clown fish that lives in a sea anemone, whereas other species are not able to. A clown fish’s predators are not able to predate on its prey due to the reaction it would have with the anemone. Natural Selection Natural selectionThe evolutionary adaptation where the natural environment “selects” for certain traits among the population. Chemical Connections to Biology Section 4 MatterWhat organisms are composed of, which is anything that has mass and takes up space. Protons Neutrons Electrons Charge Positive No charge Negative Location Nucleus of atom With protons Around nucleus Responsible for Yes No No Atomic Number? Contributes to Mass Yes Yes No Number? Influences number of No No Yes bonds formed? Changes in Isotopes? No Yes No Changes in Ions No No Yes Things to Remember Nonpolar Covalent Bond are equal sharing. Polar Covalent Bond a re unequal sharing. Ionic Bond o pposites attract. Hydrogen Bond weakest bonds(water). An atomic number represents the number of protons, which is important to that element. The mass number and atomic mass is the sum of the number of protons/neutrons in the atomic nucleus. Isotopes ● Some atoms have more neutrons than others atoms of the same element, and as a result have a greater mass. The different atomic forms of the same element is called an isotope. ● A radioactive isotope is one where the nucleus decays, which randomly gives off particles and energy. ● Cells use the radioisotope as they would the nonradioactive isotope, thus a diagnosis can be made. ● Radiometric Dating is used to study evolution. The halflife of a radioactive isotope is measured to determine the age of a fossil. Electron Distribution and Chemical Properties ● The chemical behavior of an atom can be determined by the distribution of electrons in the atom’s electron shells. You can “build” atoms by adding one proton and electron at a time. ● Such chemical behavior of an atom is decided mostly on the number of electrons in the outermost shell. ● The outermost electrons are the valence electrons, and the outermost electron shell is the valence shell. ● Certain atoms are chemically reactive because they have incomplete valence shells. Bonds Section 5 A covalent bond is sharing a pair of valence electrons by two atoms. Two or more atoms held together by covalent bonds constitute a molecule. A compound is a combination of two or more different elements. ● The attraction of a certain atom for the electrons of a covalent bond is known as its electronegativity. The more electronegative the atom is, the stronger it pulls shared electrons towards itself. ● For different atoms that have similar electronegativities, they will share the electrons equally and form a nonpolar covalent bond. When one atom has a stronger electronegativity than the other, the electrons seem to lean towards the more electronegative atom, which is called polar covalent bond. Ionic Bonds Two atoms can be so unequal in their attraction for valence electrons that the most electronegative atom strips away an electron from its partner; there is an electron transfer between the atoms. ● IonA charged atom(or molecule). ● CationWhen the charge is positive. ● AnionWhen the charge is negative. ● Ionic bondThe opposite of the cation and anion, it creates an attraction. Any two ions of opposite charge can form this. ● Ionic compounds(or salts)Compounds formed by ionic bonds. The pH scale is a log scale ● A solution with a pH 3 has 1 times more H+ ions than a solution with a pH 4. ● A solution with a pH 12 has ten times less H+ ions than a solution with a pH 2. Buffers Buffers are substances that minimize changes in concentrations of H+ and OH in a solution. The internal pH of most living cells must remain close to pH 7.2. In liquid water, a small percentage of water molecules break apart into ions. ● Some are hydrogen ions(H+). ● Some are Hydroxide ions(OH). ● Both types are very reactive. The lower the pH, the more ACIDIC. AcidIncreases the H+ concentration. BaseReduces the H+ concentration. The higher the pH, the more BASIC. Carbon Section 6 Out of every element, carbon(C) can create large and complex molecules when they are bonded to other atoms like ● Hydrogen(H) ● Oxygen(O) ● Nitrogen(N) ● Sulfur(S) ● Although cells are between 75%95% water, the rest consists of carbonbased compounds. ● Carbon has the unparalleled ability to create large and diverse molecules. Carbohydrates Lipids Nucleic Acids Proteins *Remember the elements of life: Carbon hydrogen, oxygen, nitrogen; with more miniscule amounts of sulfur and phosphorus. Carbon is able to bond to a variety of atoms such as: ● Oxygen ● Hydrogen ● Nitrogen Carbon atoms are also able to bond to other carbons, which forms the carbon skeleton of organic compounds. Organic Chemistry is the study of Carbon Compounds Compounds that contain carbon are claimed to be organic. The branch that studies such a thing specifically is organic chemistry. Carbon is versatileit can be used to create an inexhaustible variety of organic molecules. Organic Molecules and the Origin of Life on Earth At around 1953 Stanley Miller was able to stimulate early conditions on Earth in a lab. He then showed through an experiment how organic molecules could form. ● Cellulose is a polymer of glucose What happens when we ingest cellulose? ● Enzymes that digest starch by hydrolyzing αlinkages can’t hydrolyze β linkages in cellulose ● Cellulose in human food passes through the digestive tract as insoluble fiber Lipids are a diverse group of hydrophobic molecules Section 8 Lipids have little or no affinity for water! Lipids are hydrophobic! Lipids are important in longterm energy storage! The most biologically important lipids are fats, phospholipids , and steroids Fats Fats are constructed from two types of smaller molecules: glycerol and 3 fatty acids. ● Fatty acids vary in length (number of carbons) and in the number and locations of double bonds ● Saturated fatty acids have the maximum number of hydrogen atoms possible and no double bonds ● Animal fats, solid at room temperature ● Unsaturated fatty acids have one or more double bonds. ● Plant and fish fats, can be called oils, liquid at room temp Phospholipids and steroids are important lipids with a variety of functions Phospholipids are the major component of all cell membranes. Phospholipids cluster into a bilayer of phospholipids. ● Phospholipids and steroids are important lipids with a variety of function ● A common component in animal cell membranes a starting material for making steroids Proteins include a diversity of structures, resulting in a wide range of functions Section 9 ● Proteins account for more than 50% of the dry mass of most cells ● Protein functions include defense, transportation, storage, cellular communication, movement, and structural support. ● Life would not be possible without catalysts ● Enzymatic proteins act as catalysts, to speed up chemical reactions without being consumed in the reaction ● Proteins are unbranched polymers built from the same set of 20 amino acids Protein Structure and Function A functional protein consists of one or more polypeptides precisely twisted, folded, and coiled into a unique shape The amino acid sequence of each polypeptide leads to a protein’s threedimensional structure A protein’s structure determines its function. Four Levels of Protein Structure ● Proteins are very diverse, but share three levels of structure called primary, secondary, and tertiary structure ● A fourth level, quaternary structure, arises when a protein consists of two or more polypeptide chains The primary structure of a protein is its unique sequence of amino aci s. Secondary structure, found in most proteins, consists of localized coils and folds in the polypeptide chain. Tertiary structure is the fully folded polypeptide chain(protein). Proteins have a wide range of functions and structures ● If a protein’s shape is altered, it can no longer function. ● In the process of denaturation, a protein unravels, loses its specific shape, and loses its function. ● Proteins can be denatured by changes in salt concentration, changes in pH, or high heat. Nucleic acids store, transmit, and help express hereditary information Section 10 ● The amino acid sequence of a polypeptide is programmed by a unit of inheritance called a gene. ● Genes are made of DNA, a nucleic acid made of monomers called nucleotides. The Roles of Nucleic Acids There are two types of nucleic acids: ● Deoxyribonucleic acid (DNA) ● Ribonucleic acid (RNA) ● DNA provides directions for its own replication ● DNA also directs synthesis of messenger RNA(mRNA) and, through mRNA, controls protein synthesis. Nucleic acids are polymers of nucleotides ● RNA is usually a single polynucleotide strand. DNA nitrogenous bases are ● adenine (A) Adenine>Thymine and Cytosine>Guanine ● Thymine(T) ● cytosine (C) ● guanine (G) ● RNA also has A, C, and G, but instead of T, it has uracil (U). *These do not match with anything else. At all. What is the difference between DNA and RNA? Section 11 DNADeoxyribonucleic acid, is a molecule that carries genetic information used in development, growth, reproduction, and function of all living organisms as well as various viruses. It is a DOUBLE HELIX. It also has THYMINE, NOT URACIL. RNARIbonucleic acid, it is a nucleic acid that is present in all living cells. It acts as a messenger that carries instructions from DNA for controlling the synthesis of proteins. However, some viruses with RNA instead of DNA carry the genetic information. It is a SINGLE STRAND. It also has URACIL, NOT THYMINE. *Some of what is on this Study Guide may or may not be on the Exam, but the majority of it will be.
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