What characteristics do we use to define life?
o Evolutionary Adaptation
o Response to the Environment
o Growth and Development
o Energy Processing
What is Science? What limitations does it have?
Science is the process of discovery, the process by which study of the natural world around us. A theory in science cannot be proven, it can only be falsified. Science includes challenge, adventure, luck, planning, reasoning, creativity, patience, and persistence.
What is the Scientific Method? What are the steps? Describe each. The Scientific Method is a method to test a question in science. Steps:
o Exploration and Observation
o Forming and Testing Hypotheses
o Deductive Reasoning
o Interpreting the Data
What are the qualifications of a scientific hypothesis? How is it formed and tested? Can you prove a hypothesis? What makes a good hypothesis?
A scientific hypothesis has to be testable, falsifiable, and can be eliminated but cannot be confirmed with absolute certainty. Scientists make hypothesis by preforming preliminary observations and collecting data on an idea that they may have. Scientist then preform experiments to either support or eliminate their hypothesis. A hypothesis cannot be proven but can only be supported through thorough data and claims.
If you want to learn more check out How does structure affect function in cells?
What is the difference between a hypothesis and scientific theory? We also discuss several other topics like What is descartes’ dreaming argument?
A hypothesis is a testable explanation for a set of observations based on the available data and guide by inductive reasoning. A hypothesis is narrower in scope than a theory. A scientific theory is a much broader version of the hypothesis.
Why should variables be limited in an experiment? What is the purpose of a control group? How do we minimize bias in an experiment?We also discuss several other topics like How many centimeters in 15km?
A control group is used as a standard of comparison. With too many variables going at once data will not be conclusive. To minimize the bias in an experiment you are able to do a double-blind experiment or study where neither the technician nor the subject know what the experiment is about. We also discuss several other topics like What was galileo famous for?
How does peer review work? Why is it important? Why do we need to consider the source of scientific information? What kind of sources are most reliable?
Scientist submit a paper to a journal, the journal sends the paper to other scientist for peer review. The paper is then returned to authors for revision (maybe more than once) those are primary sources. Secondary sources appear on radio, TV, magazines and often have a middle man interpreting scientific sources. Primary sources are often the most reliable. Secondary sources are able to be reliable in the correct setting.
Biology: the scientific study of life.
Science: an approach to understanding the natural world.
Scientific Method: a method of procedure that includes observation, measurement, experiment, formulation, testing, modification, of hypothesis.
Hypothesis: a testable explanation for a set of observations based on the available data and guide by inductive reasoning. A hypothesis is narrower in scope than a theory.
Experiment: a scientific test. Often carried out under controlled conditions that involve manipulating one factor in a system in order to see the effects of changing that factor. If you want to learn more check out Why do governments intervene in markets?
Variable: a factor that varies in an experiment.
Control Group: used as a standard for comparison.
Bias: effects that a conclusion may be incorrect.
Scientific Theory: an explanation that is broader in scope than a hypothesis, generates new hypotheses, and is supported by a large body of evidence.
Emergent Properties: new properties that arise with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases. Don't forget about the age old question of What does amicus curiae mean?
Positive Feedback: end product speeds up process.
Negative Feedback: accumulation of an end product of a process slows that process.
Themes help connect the concepts of biology:
o New properties emerge at each level in the biological hierarchy. o Structure and function are correlated.
o Cells are an organism’s basic unit of structure and function. o Continuity of life based on DNA.
o Feedback mechanisms regulate biological systems.
o Organisms interact with their environments.
Structure and function of living organisms are very closely related. DNA > RNA > Protein
Ecosystem dynamics included two major process:
o Cycling of nutrients.
o Flow of energy from sunlight to producers to consumers.
Evolution is the reason we have such a variety of living things. Inductive Reasoning: using specific observations to form a general principle. Deductive Reasoning: using general premises to make specific predictions. Some scientific studies may not be possible.
Concepts to Understand
o Briefly describe the unifying themes that characterize biological sciences.
o Distinguish among the three domains of life, and the eukaryotic kingdoms.
o Distinguish between the following pairs of terms: discovery science and hypothesis-based science, inductive and deductive reasoning, hypothesis and theory.
How do we use the atomic number and atomic mass of an element to determine the number of neutrons, protons, and electrons of that element?
The atomic number tells us the protons. The atomic number also represents the number of electrons. We use the atomic mass to determine how many neutrons are in the atom. You have to take the atomic number and subtract it from the atomic mass to determine the number of neutrons.
What makes some atoms inert?
When an atoms outer shell is completely full of electrons. (8)
Atomic Mass: total mass of an atom.
Atomic Number: the number of protons in the nucleus of atoms. Proton: subatomic particle with a single positive charge.
Neutron: subatomic particle having no electrical charge.
Electron: subatomic particle with a single negative electrical charge.
Valance Shell: outermost energy shell of an atom, containing the valance electrons involved in the chemical reactions of that atom.
Covalent Bond: type of strong chemical bond in which two atoms share one or more pairs of valance electrons.
Electronegativity: the attraction of a given atom for the electrons of a covalent bond.
Polar: covalent bond between atoms that differ in electronegativity. Shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.
Nonpolar: covalent bond in which electrons are shared equally between two atoms of similar electronegativity.
Ionic Bond: chemical bond resulting from the attraction between oppositely charged ions.
Ion: an atom or group of atoms that has gained or lost one or more electrons, thus acquiring a charge.
Cation: positively charged ion.
Anion: negatively charged ion.
Hydrogen Bond: type of weak chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule or in another region of the same molecule.
Compound: substance consisting of two or more different elements combined in a fixed ratio.
There are 92 natural elements.
o 25 elements are essential for life.
o C, H, O, N make up 96% of living matter.
Nonpolar covalent bonds: atoms are shared equally.
Polar covalent bond: atoms are shared unequally.
Hydrogen bond: hydrogen atom that is covalently bonded to one electronegative atom is also attracted to another electronegative atom.
Concepts to Understand
o Identify the four major elements.
o Distinguish between the following sets of terms: protons, neutrons, electrons, cations, and anions.
o Distinguish between and discuss the biological importance of the following: nonpolar covalent bonds, polar covalent bond, ionic bonds, and hydrogen bonds.
Why is water important to biology? What allows water to have these properties?
o Cohesive behavior: water is able to stick to each other and travel in large strands.
o Ability to moderate temperature: large bodies of water are able to cool down an area because of the amount of heat that it absorbs but does not give off. o Expansion upon freezing: when water freezes, molecules become arranged in a fixed pattern.
o Versatility as a solvent: water can dissolve most solutions.
Hydrophobic: having no affinity for water.
Hydrophilic: having an affinity for water.
Solute: a substance that is dissolved in a solution.
Solvent: the dissolving agent of a solution.
Solution: liquid that is homogeneous mixture of two or more substance. Additional Concepts
Heat: measure of the total amount of kinetic energy due to molecular motion.
Temperature: measures the intensity of heat due to the average kinetic energy of molecules.
Concepts to Understand
o List and explain the four properties of water that emerge as a result of its ability to for hydrogen bonds.
o Distinguish between the following set of terms: hydrophobic, hydrophilic, solute, solvent, and solution.
What are the functional groups and properties?
Functional groups are components of organic molecules that are most commonly involved in chemical reactions.
o The number and arrangement of functional groups give each molecule its unique properties.
What are the types of isomers?
o Structural Isomers
o Geometric Isomers
Isomer: one of two or more compounds that have the same numbers of atoms of the same elements but different structures and hence different properties.
Carbon is the backbone of life.
Hydrocarbons: organic molecules that consist only of carbon and hydrogen. Concepts to Understand
o Explain how carbon’s electron configuration explains its ability to form large, complex, diverse organic molecules.
o Describe how carbon skeletons may vary and explain how this variation contributes to the diversity and complexity of organic molecules.
o Distinguish among the three types of isomers: structural, geometric, and enantiomer.
o Name the major functional groups found in organic molecules and describe the basic structure of each functional group.
What are the four macromolecules of life? What is the basic structure? What types of bonds link the monomers of each together? What are the characteristics and functions?
o Carbohydrates: sugars and polymers of sugars.
o Sugars and storage molecules (energy).
o Dietary fiber.
o Lipids: consist mostly of hydrocarbons, which from nonpolar covalent bonds. o Fats.
o Proteins: polymers constructed from amino acid monomers.
o Nucleic Acids: made of nucleotide monomers.
o Each nucleotide consists of pentose sugar, phosphate group, and nitrogenous acid.
What is a hydrolysis reaction? Dehydration reaction?
A dehydration reaction is a chemical reaction in which two molecules become covalently bonded together with the removal of a water molecule.
A hydrolysis reaction is a chemical reaction in which two molecules are broken apart by adding a water molecule.
What makes starch and cellulose similar? What makes them different? How to plants and animals store excess carbohydrates?
Starch and cellulose are made of the same monomer. The arrangements of the monomers are the only difference, therefor causing them to act different from each other. Animals store carbs in cells for access to quick energy as glycogen. Plants store carbs as a starch in cells as well.
What makes one amino acid different from another? How can we classify amino acids?
Different amino acids have different R groups attached to a carbon.
We can classify amino acids by their R groups, basis of nutrition, and basis of catabolism.
What levels of organization are used to describe the structure of proteins?
o Primary: linear sequence of amino acids.
o Secondary: a helix and a folded structure called pleated sheet. o Tertiary: consists of primary and secondary to form a polypeptide. o Quaternary: two or more polypeptides interacting.
How do enzymes work? Why is the 3D shape of proteins so important?
Enzymes are a type of proteins that act as a catalyst and speeds up chemical reactions. The shape of the proteins depends on how the protein functions. The sequence of amino acids determines the proteins 3D shape.
What are the major difference between DNA and RNA? Why can we use the sequence of nucleotides of one strand of DNA to predict the sequence of nucleotides of the other strand? What is the complementary based pairing rule?
RNA has uracil instead of thymine and only consists of a single strand. We can predict the second strand of DNA because certain nucleotides can only bond with one other nucleotide. The complementary pairing rule means only A can bond with T and C can only bond with G.
Polymer: long molecule consisting of many similar or identical monomers linked together by covalent bonds.
Monomer: subunit that serves as the building block of a polymer.
Monosaccharide: simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Simple sugars.
Disaccharide: double sugar, consisting of two monosaccharides joined by a glyosidic linkage formed by dehydration reaction.
Polysaccharide: polymer of many monosaccharides, formed by dehydration reactions.
Hydrolysis: chemical reaction that breaks bonds between two molecules by the addition of water; functions in disassembly of polymers and monomers.
Dehydration: chemical reaction in which two molecules become covalently bonded to each other with the removal of a water molecule.
Fat: lipid consisting of three fatty acids linked to one glycerol molecule.
Steroid: type of lipid characterized by a carbon skeleton consisting of four fused rings with various chemical groups attached.
Phospholipid: lipid made up of glycerol joined to two fatty acids and phosphate group.
Saturated Fat: fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms that are attached to the carbon skeleton.
Unsaturated Fat: fatty acid that has one or more double bonds between carbons in the hydrocarbon tail.
Trans Fat: unsaturated fat, formed artificially during hydrogenation of oils containing one or more trans double bonds.
Amino Acid: an organic molecule possessing both a carboxyl and amino group. Polypeptide: polymer of many amino acids linked together by peptide bonds.
Nucleotide: building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and one to three phosphate group.
Purine: one of two types of nitrogenous bases found in nucleotides, characterized by a six-membered ring fused to a five-membered ring. Adenine (A) and guanine (G).
Pyrimidine: one of two types of nitrogenous found in nucleotides, characterized by a six-membered ring. Cytosine (C), thymine (T), Uracil (U).
Denature: in proteins, a process in which a protein loses its native shape due to the disruption of weak chemical bonds and interactions, thereby becoming biologically inactive; in DNA, the separation of the two strands of the double helix.
Synthesis: dehydration reaction.
Breakdown: hydrolysis reaction.
Glycosidic linkage: covalent bond between to monosaccharides. Polysaccharides: polymers of sugar.
Phospholipid: two fatty acids and a phosphate group attach to glycerol. Denature: change in the tertiary or quaternary structure.
o A always bonds with T.
o C always bonds with G.
o Adenine (A)
o Guanine (G)
o Cytosine (C)
o Uracil (U)
Concepts to Understand
o List and describe the four major classes of molecules.
o Describe the formation of a glycosidic linkage ad distinguish between monosaccharides, disaccharides, and polysaccharides.
o Distinguish between saturated and unsaturated fats and cis and trans fat molecules.
o Describe the four levels of protein structure.
o Use the nucleotide sequence of one strand of DNA to determine the nucleotide sequence of the complimentary strand of DNA.
What is the cell theory?
o All living things are composed of one or more cells.
o All cells come from pre-existing cells.
o Cells are the basic organizational unit of life.
What do prokaryotic cells and eukaryotic cells have in common?
o Enclosed by plasma membrane.
o Have cytoplasm.
o Use DNA as genetic information.
o Have ribosomes for making proteins.
Why are some cells limited in size?
The S-to-V ratio of the cell has to remain small enough for the exchange of materials to occur. Exchange of materials has to be done quickly in order for the cell to work correctly.
What are the cell structures, functions, and where are they found?
o Plasma Membrane:
o Selective barrier that allows sufficient passage of oxygen, nutrients, and waste.
o General structure: phospholipid bilayer.
o Double membrane.
o Contains DNA and RNA.
o Controls cell reproduction.
o Pores regulate the entry and exit of molecules from the nucleus. o Ribosomes:
o Made of protein and rRNA.
o Translation: protein synthesis.
o Free floating or attached to the E.R.
o Endoplasmic Reticulum:
o Smooth E.R. (lacks ribosomes)
o Rough E.R. (ribosomes stud surface)
o Golgi Apparatus:
o Modifies products of the ER.
o Manufactures certain macromolecules.
o Sorts and packages materials into transport vesicles.
o Membranous sac of hydrolytic enzymes that can digest
o Central Vacuoles:
o Helps maintain pressure in plant cells.
o Sites of cellular respiration. (generates ATP)
o Plants only.
o Site of photosynthesis.
o Chloroplasts structure includes:
Thylakoids: membranous sacs, stacked to form a granum.
Stroma: internal fluid.
o Cell Wall:
o Extracellular structure that distinguishes plant cells from animal cells. What are the types of intercellular junctions and what are their functions?
o Plasmodensmata: channels that perforate plant cell walls, allows water and small solutes to pass from cell to cell.
o Tight Junctions: no materials pass.
o Desmosomes: holds cells together, no materials pass.
o Gap Junctions: allows for communication, allows materials to pass from cell to cell.
What makes plant and animal cells different?
There are certain structures in plant cells that are not in animal cells such as cell walls and chloroplasts.
Prokaryote: type of cell lacking a membrane-enclosed nucleus and membrane enclosed organelles.
Eukaryote: type of cell with a membrane-enclosed nucleus and membrane enclosed organelles.
Plasma Membrane: membrane at the boundary of every cell that acts as a selective barrier, regulating the cell’s chemical composition.
Organelle: any of several membrane-enclosed structures with specialized functions.
Nucleus: atoms central core containing protons and neutrons. The organelle of a eukaryotic cell that contains the genetic material in the form of chromosomes, made up of chromatin.
Nucleoid Region: membrane-enclosed region in a prokaryotic cell where its chromosomes are located.
Phospholipid Bilayer: general structure of plasma membrane. 12
Ribosomes: a complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm.
Endomembrane System: collection of membranes inside and surrounding a eukaryotic cell, related wither through direct physical contact or by the transfer of membranous vesicles; includes the plasma membrane, nuclear envelope, the smooth and rough endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, vacuoles.
Nuclear Envelope: the double membrane in a eukaryotic cell that surrounds the nucleus, perforated with pores that regulate traffic with the cytoplasm.
Endoplasmic Reticulum: an extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.
Golgi Apparatus: organelle in eukaryotic cells consisting of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum and synthesize some products, notably noncellulose carbs.
Lysosomes: membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm of animal cells and some parts.
Vacuoles: membrane-bounded vesicle whose specialized function varies in different kinds of cells.
Mitochondria: organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP.
Chloroplast: organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water.
Cytoskeleton: network of microtubules, microfilaments and intermediate filaments that extend throughout the cytoplasm and serve a variety of mechanical, transport, and signaling functions.
Cell Wall: protective layer external to the plasma membrane in the cells of plants, prokaryotes, fungi, and some protists.
Nuclei have a double membrane.
o Intermediate Filaments.
Concepts to Understand
o Distinguish between the following pairs: prokaryotic cells, eukaryotic cells, smooth ER, rough ER.
o Describe the structure and function of the components of the endomembrane system.
o Briefly explain the role of mitochondria and chloroplasts o Describe the functions of the cytoskeleton.
o Compare the structure and functions of microtubules, microfilaments, and intermediate filaments.
o Describe four different intercellular junctions.