Exam 1 Study Guide NEW. 100% VERIFIED | Ohio State University

CHAPTER 1 What are the 5 characteristics that distinguish life from non-life? • Organized by Cells • Use Resources for Energy • Grows and Develops • Responds to stimulus or Environment • Reproduce Scientists ...

CHAPTER 1 What are the 5 characteristics that distinguish life from non-life? • Organized by Cells • Use Resources for Energy • Grows and Develops • Responds to stimulus or Environment • Reproduce Scientists and their contributions • Robert Hooke- Created first microscope, (only 30X), first guy to see cells • Anton Van Leeuwenhoek – made much more powerful microscope (up to 300X) could see animalcules... also saw blood cells and sperm cells • Rudolph Virchow- proposed that all cells arise from cells already in existence … came to form cell theory…. All cells are formed from pre existing cells • Louis Pasteur- Proved Virchow right, as well as cell theory, disproved spontaneous generation in non-living cells • Charles Darwin and Alfred Russel Wallace- All diverse species- all distinct identifiable types of organisms, are connected by common ancestry. • James Watson and Francis Crick- Proposed that DNA is a double stranded helix • Rosalind Franklin- performed structural analyses that led to that model • Francis Crick- First articulated central dogma • Carl Woese- Tried to understand phylogeny (evolutionary relationships) with other scientists. observed RNA • Carlos Linnaeus- Established the two-part name unique system for naming species that is still in use today • Robert Simmons and Lue Scheepers- Giraffe Hypothesis • Wittlingers Group- Ant Hypothesis • Theodore Boveri & Walter Sutton- Chromosomal Theory of Intelligence • Chargaff – created data to show that 1:1 molar ratio between nitrogenous bases…help Watson and crick discover the double helix structure Know the components of cell theory and their implications for living organisms today. The basic tenets of the cell theory are as follows: • All living things are made up of one or more cells. • The cell is the structural and functional unit of all living things. • Cells come from pre-existing cells through the process of division. • All cells are the same in regard to chemical composition. • All energy flow (metabolism and biochemistry) of life occurs within the cell. The observations of Hooke and van Leeuwenhoek documenting the existence of microscopic cells formed the basis of the cell theory stating that all living things are composed of cells Define biological evolution. • Biological evolution is the process through which the characteristics of organisms change over successive generations, by means of genetic variation and natural selection. It is most commonly defined as "changes in gene frequencies in populations." Be able to describe how natural selection acts to drive evolution. • Natural selection leads to evolutionary change when individuals with certain characteristics have a greater survival or reproductive rate than other individuals in a population and pass on these inheritable genetic characteristics to their offspring. Who first proposed natural selection as mechanism for evolution? • Charles Darwin and Alfred Russel Wallace published a new evolutionary theory, explained in detail in Darwin's On the Origin of Species (1859). What conditions must be present for natural selection to act? • Variation- individuals in the population must differ with respect to the trait in question. Without this variation, all individuals will have the same trait value and cannot be distinguished with respect to that trait. • Heritability- The variation found in the population must (at least partially) be heritable, e.g. transmitted from parent to offspring. If the variation is the trait is due entirely to environment, for example, changes in the parent population would not affect the characteristics of the offspring population. • Differential Mortality: Finally, individuals must have a probability of survival that is a function of the value of the trait in question. If all individuals, regardless of their trait value, had an equal probability of survival and fecundity, no predictable change in the mean value of the population would occur. What is the chromosomal theory of inheritance? • Chromosomes, which are seen in all dividing cells and pass from one generation to the next, are the basis for all genetic inheritance. Over a period of time random mutation creates changes in DNA sequence of genes What is the Central Dogma? DNA- RNA-- Proteins Describe the three domains of life Bacteria, Archaea, Eukarya What type of cells are present in each domain? • Bacteria- Prokaryotes • Archaea- mostly prokaryotes, some eukaryotes, • Eukarya – Eukaryotes Know the steps of the scientific method. The universally-accepted, organized approach to the study of science, which consists of the following steps: 1) Observation - collecting data. 2) Hypothesis - forming a preliminary possible explanation of the data. 3) Testing - test the hypothesis by collecting more data. 4) Results - interpreting the results of the test and deciding if the hypothesis should be rejected. The hypothesis is rejected if the results contradict it, showing that it is wrong. 5) Conclusion - stating a conclusion that can be evaluated independently by others. Define and contrast hypothesis and theory • Hypothesis- A testable statement that explains a phenomenon or a set of observations. • Theory- An explanation for a broad class of phenomena that is supported by a wide body of evidence. A theory serves as a framework for the development of new hypotheses. • A hypothesis is an attempt to explain phenomena. It is a proposal, a guess used to understand and/or predict something. A theory is the result of testing a hypothesis and developing an explanation that is assumed to be true about something. A theory replaces the hypothesis after testing confirms the hypothesis, or the hypothesis is modified and tested again, until predictable results occur. CHAPTER 1 VOCAB Adaptation - Any heritable trait that increases the fitness of an individual with that trait, compared with individuals without that trait, in a particular environment. Eukaryote - A cell that contains a nucleus and membrane bound organelles Fitness - Ability of an organism to survive and reproduce in its environment Phylogeny - the development or evolution of a particular group of organisms (Tree of Life) Phylum - (plural: phyla) In Linnaeus' system, a taxonomic category above the class level and below the kingdom level. In plants, sometimes called a division. Prediction - A measurable or observable result of an experiment based on a particular hypothesis. A correct prediction provides support for the hypothesis being tested. Prokaryote - A member of the domain Bacteria or Archaea; a unicellular organism lacking a nucleus and containing relatively few organelles or cytoskeletal components. Scientific name - Genus name and the species name put together by the binomial nomenclature system. Speciation - An evolutionary process in which one species splits into two or more species. Taxon - taxa (pl.) Any named group of organisms at any level of a classification system. CHAPTER 2 Describe the chemical evolution hypothesis. The theory that simple chemical compounds in the early atmosphere and ocean combined via chemical reactions to form larger, more complex substances, eventually leading to the origin of life and the start of biological evolution. What are the six atoms that make up the majority of a cell’s biomass (living matter)? • Hydrogen • Carbon • Nitrogen • Oxygen • Phosphorous • Sulfur Know basic atomic structure. How are electrons arranged around the nucleus of an atom? • Nucleus holds protons and neutrons • Electrons surround it • Protons is the lower number (atomic Number) • Higher number is atomic mass (Protons + Neutrons) • Can always calculate the neutrons • Protons and Electrons are equal in number What makes an atom “reactive”? The number of electrons in the outermost shell of an atom determines its reactivity. Noble gases have low reactivity because they have full electron shells. Halogens are highly reactive because they readily gain an electron to fill their outermost shell What are three types of bonds we discussed in lecture? What is their relative strength? • Covalent bonds, Ionic Bonds and Hydrogen Bonds • ionic > covalent > H-bond > dipole-dipole > van der Waals Contrast a polar and non-polar bond. • A Nonpolar bond shares electrons equally, a polar bond does not share electrons equally • May pull electrons with different strengths because of electronegativity • Nonpolar covalent bond- shares electrons equally • Polar covalent bond- shares electrons unequally Know the characteristics of water that are critical to life on Earth. Water density - the solidity or thickness of a substance High Specific Heat - The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree Celsius Heat vaporization - heat absorbed when liquid vaporizes Universal Solvent - the quality of water that makes it able to dissolve more substances than any other solvent can Cohesion/Adhesion - Cohesion is when the particles of the same substance stick together. Adhesion is particles from different substances stick. Surface tension - a force that makes molecules push together to form a layer on the surface Insulator - a device or substance that doesn't conduct electricity Be able to identify reactants, products, & direction of a chemical reaction. Reactants – Simple compounds abundant on early earth. Products – Complex molecules formed from simpler ones. Reactants --> Products Understand and distinguish between acids and bases (alkaline). Acids = donate protons Bases = accept protons Be able to determine if a chemical reaction is spontaneous. - Happens without an input of energy Know the difference between endothermic and exothermic reactions - Exothermic release energy - Endothermic asborbs energy Contrast kinetic and potential energy, and provide examples of each energy type. Understand how potential energy relates to the position of electrons around a molecule. • Energy is the ability to do work • Kinetic Energy = energy of motion – mechanical energy, thermal energy (heat), radiant energy (sunlight energy … electromagnetic energy) • Potential Energy = stored energy: energy an object has by virtue of its position – chemical energy (energy stored chemical bonds due to position of atoms) What was Stanley Miller’s contribution to natural history/biology? Understand Miller’s “Spark-discharge” experiment and his conclusions. Stanley Miller tried to recreate early atmosphere in lab. YouTube video we watched The prebiotic soup model proposes that certain molecules were synthesis from gases from the atmosphere or arrived via meteorites. Afterward they would have condensed with rain and accumulated in oceans. This process would result in “organic soup” that allowed for continued construction of larger, even more complex molecules The surface metabolism model- suggests that dissolved gases came in contact with minerals lining the walls of deep sea vents and formed more complex organic molecules. How does the surface metabolism model of chemical evolution differ from the prebiotic soup model? The surface metabolism model evokes mineral catalysts What is a functional group? How do functional groups affect the reactivity of organic compounds? Be able to recognize the six functional groups found most frequently in living organisms. • Carbon atoms provide the structural framework of organic compounds (“carbon skeleton”) • Functional groups attached to skeleton determine the compound’s chemical behavior – Contain H, N, O, P, & S • Amino • Carboxyl • Carbonyl • Hydroxyl • Phosphate • Sulfhydryl CHAPTER 2 VOCAB 2nd Law of Thermodynamics - the state of entropy of the entire universe, as an isolated system, will always increase and never decrease over the course of time. Atomic number - the number of protons in the nucleus which in a neutral atom equals the number of electrons outside the nucleus Buffer - A solution which can maintain an almost constant pH value when dilute acids or alkalis are added to it Electronegativity - A measure of the relative tendency of an atom to attract electrons to itself when chemically combined with another atom. Free radical – A substance of one or two unpaired electrons (highly reactive) Hydrocarbon – Compounds composed of only carbon and hydrogen Hydrophilic – Attracted to water Hydrophobic – Repels water Ion – Electorally charged atoms or group of atoms (H-), (H+) Mass number - the number of protons and neutrons in an atom's nucleus Orbital – is used to describe the spatial distribution of the electron Organic compound – Consist of Carbons and Hydrogens pH scale - is a numeric scale used to specify the acidity or basicity of an aqueous solution. Solute – A substance that dissolves in a solvent to form a solution Solution – A mixture of a substance that has a uniform composition; a homogeneous mixture Solvent – The dissolving medium of a solution; it is normally the component of a solution present in greater amount Valence shell – A shell of closely spaced molecular orbitals that is essentially fully occupied by electrons CHAPTER 3 Describe the structure of an amino acid. What distinguishes one amino acid from another? Know how each amino acid behaves in aqueous solution (non-polar, polar, acid, base). Contrast a condensation reaction with hydrolysis. What conditions cause these reactions to occur in a cell? An amino acid consisted of: • monomer that makes up proteins • carboxyl and amino functional groups • hydrogen atom • R-group The change in its R-group In an aqueous solution: • Non-poplar = Hydrophobic • Polar = Hydrophilic • Acid = donates protons • Base = accepts protons What is the difference between Hydrolysis and Condensation? • Hydrolysis is the reverse of condensation • Condensation reactions – makes chemical bonds • Hydrolysis – breaks chemical bonds • Polymers - are made up by condensation reactions, and they are broken by hydrolysis reactions • During condensation reactions, water molecule can be released. In the hydrolysis reactions, water molecule is incorporated into the molecules What is the primary structure of a protein? The first level of protein structure; the specific sequence of amino acids making up a polypeptide chain. What causes a polypeptide to bend and fold into its secondary structure? The polypeptide backbone of a protein folding is due to hydrogen bond formation between peptide linkages. What causes it to bend and fold again, to form its tertiary structure? • Ionic Bonds • Hydrogen Bonds (between two side chains) • Hydrogen Bonds (between side chains and carbonyl group on backbone) • Disulfide Bonds Understand why a protein’s shape is so important to its function. Proteins catalyze chemical reactions by bringing them together in the right orientation and helping them react together. If they have the wrong shape they cannot do this. This is because with the wrong shape, the pieces will not fit together properly. Describe various functions of different classes of proteins. • Defensive (Antibodies, or immunoglobulin, are a core part of your immune system, keeping diseases at bay.) • Enzymatic (Enzymatic proteins accelerate metabolic processes in your cells, including liver functions, stomach digestion, blood clotting and converting glycogen to glucose.) • Hormonal (protein-based chemicals secreted by the cells of the endocrine glands.) • Receptor (Located on the outer part of the cells, receptor proteins control the substances that enter and leave the cells, including water and nutrients.) • Storage (Storage proteins mainly store mineral ions such as potassium in your body.) • Structural (Also known as fibrous proteins, structural proteins are necessary components of your body they include collagen, keratin and elastin.) • Transport (Transport proteins carry vital materials to the cells.) • Contractile (Also known as motor proteins, contractile proteins regulate the strength and speed of heart and muscle contractions. CHAPTER 3 VOCAB Peptide bond - the chemical bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid Monomer - small unit that can join together with other small units to form polymers Polymer - a large molecule made up of chains or rings of linked repeating subunits, which are called monomers Polymerization - Process by which smaller units--monomers--are joined together to form larger compounds—polymers van der Waals interactions - Van der Waals forces, relatively weak electric forces that attract neutral molecules to one another in gases, in liquefied and solidified gases, and in almost all organic liquids and solids. α-helix - a secondary structure that is a delicate coil held together by hydrogen bonding between every fourth amino acid β-pleated sheet - One form of the secondary structure of proteins in which the polypeptide chain folds back and forth, or where two regions of the chain lie parallel to each other and are held together by hydrogen bonds. Di-sulfide bonds - chemical side bonds that are formed when the sulfur atoms in two adjacent protein chains are joined together. Quaternary structure - The fourth level of protein structure; the shape resulting from the association of two or more polypeptide subunits. Denaturation - loss of an enzyme's normal shape so that it no longer functions; caused by a less than optimal pH and temperature Prion – misfolded proteins that become infectious and cause disease’s such as (Mad cow or Creutzfeldt-Jakob) Catalyst - speed up chemical reactions Enzyme - any of several complex proteins that are produced by cells and act as catalysts in specific biochemical reactions Active site - The specific portion of an enzyme that attaches to the substrate by means of weak chemical bonds. Chapter 4 Describe the structure of a nucleotide. • Nucleotides are monomers that consist of a sugar, a phosphate group, and a nitrogen containing base • Nucleotides polymerize to form nucleic acids through formation of phosphodiester linkages between the 3’ hydroxyl on one nucleotide and the 5’ phosphate on another • During polymerization, activated nucleotides are added to the 3’ end of a nucleic acid strand. What distinguishes one nucleotide from another? • Nitrogenous Base (Adenine, Guanine, Cytosine, Thymine, Uracil) What type of bond forms to link two nucleotides together? • Phosphodiester linkage bonds Know what is bonded to the 1’, 3’, and 5’ carbons of the pentose. • 1’- Nitrogenous Base • 5’- Phosphate Group • 3’ is your hydroxyl …. Which when bonding becomes your phosphodiester linkage Describe the directionality of a nucleic acid molecule. • Base sequence written from 5’ to 3’ end • Grows from 3’ end tho… What provides the energy for the polymerization of DNA and RNA? • Deoxy ribonucleotide triphosphate substrates (and for RNA Ribonucleotide triphosphate substrates) What determines the primary structure of a nucleic acid molecule? Know the scientists who first described the structure of DNA. • Watson and Crick (1953) Describe complementary base-pairing. • Hydrogen bonds form between G-C pairs and A-T pairs • The double stranded DNA backbones must run in antiparallel directions Describe the basic function of DNA and RNA and where each is located in a prokaryotic and eukaryotic cell. DNA replication • Each strand acts as a template, codes for the other strand • Free nucleotides are complementary to template • Semi-conservative replication (Each new strand pairs with an old strand) RNA Replication • Sugar is Ribose • Bases: G, C, A, U • Usually single—stranded often self pairs (pairs with self) • ‘Stem and loop” • Unpaired region forms a loop • Complementary base paring between antiparallel regions forms a double helix Discuss the reasons why RNA is more reactive than DNA. • Ribose sugar is more reactive • Extra OH group on ribose, less complex secondary structure • Molecule is less stable than DNA • Degrades more rapidly • RNA can act as an enzyme (ribozyme) Using a single strand of DNA as a template, be able to make a complementary strand • 5’ ATCGCTCATA 3’ • 5’ TATGAGCGAT 3’ Understand the RNA World hypothesis, and its role in the shift from chemical to biological evolution. • First life form was likely a “naked” self-replicator • Only RNA has the ability to catalyze its own polymerization • Serves as its own template • Ribozyme (enzyme)catalyzes polymerization reaction • Ribozymes play vital role in cell activity • Eventually, protein enzymes evolved • Folding brings widely spaced nucleotides together at the active site of this catalytic RNA CHAPTER 4 Vocab Adenine - A purine base that is a component of DNA and RNA, forming a base pair with thymine in DNA and with uracil in RNA. Guanine - a purine base, C 5 H 5 N 5 O, that is a fundamental constituent of DNA and RNA, in which it forms base pairs with cytosine. Thymine- a pyrimidine base, that is one of the principal components of DNA, in which it is paired with adenine Cytosine- a pyrimidine base, that is one of the fundamental components of DNA and RNA, in which it forms a base pair with guanine Antiparallel - The opposite arrangement of the sugar-phosphate backbones in a DNA double helix. Purine - Adenine and Guanine Pyrimidine - Cytosine and Thymine and Uracil (in RNA) Ribozyme - An enzymatic RNA molecule that catalyzes reactions during RNA splicing. Stem-and-loop - intramolecular base pairing is a pattern that can occur in single­stranded DNA or, more commonly, in RNA. Know as Hairpin. Sugar-phosphate backbone - The sugar-phosphate backbone forms the structural framework of nucleic acids, including DNA and RNA. This backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule. Chapter 5 Describe the structure that is common to all carbohydrates. • Characteristic carbonyl group + several –OH groups (hydroxyl groups) • Variations in (CH2O)n, where n – 3, 4, … 1000 + (e.g, C6H12O6) What distinguishes one monosaccharide from another? • Number of carbons • Position of carbonyl group • Spatial arrangement of function groups around carbons Examples: An Aldose- Carbonyl is at end of chain Ketose- Carbonyl group in middle of carbon chain Name the most common monosaccharides and polysaccharides (as discussed in lecture) Aldoses • Glyceraldehyde- (Triose sugar) 3 Carbons, 6 Hydrogens, 3 Oxygens • Ribose- (Pentose Sugar) 5 Carbons, 10 Hydrogens, 5 Oxygens • Glucose and Galactose- (Hexose sugars) 6 Carbons, 12 Hydrogens, 6 Oxygens…Glucose and Galactose are spatially different at one hydroxyl group Ketoses • Dihydroxyacetone- (Triose sugar) 3 Carbons, 6 Hydrogens, 3 Oxygens • Ribulose- (Pentose Sugar) 5 Carbons, 10 Hydrogens, 5 Oxygens • Fructose- - (Hexose sugars) 6 Carbons, 12 Hydrogens, 6 What type of bond forms between monomers to make a sugar polymer? • Glyosidic Linkages- covalent bond between 2 hydroxyl groups, causes primary & secondary structure to vary • Alpha or Beta Forms • Formed by Condensation Reactions Understand the difference between an α- and a β-glyosidic linkage. • Beta- Glycosidic Linkage- Pointed up • Alpha – Pointed up What is the consequence to a cell (in terms of these different formations)? • Humans can not digest Beta Glycosidic linkages, because we lack the enzymes needed to break the bonds, plants still provide dietary fiber • Starch Alpha Glycosidic Linkages ➢ Amylose: Unbranched Helix, Alpha 1,4 Linkages ➢ Amylopectin: Branched Helices, some Alpha 1,6 linkages • Glycogen: Highly branched helices (Many Alpha 1, 6 Glycosidic Linkages) • Cellulose has Beta Glycosidic Linkages- Hydrogen Bonding between • Chitin has Beta Glycosidic Linkages and Hydrogen Bonds • Peptidoglycan has Beta Glycosidic Linkages and Peptide bonds Discuss how (like all biomolecules) structure determines function Be able to explain why most organisms can digest starch but not cellulose. • Cellulose contains Beta Glycosidic Linkages which many organisms do not have the enzyme to break it down. However, many organisms, have amylase which is used to break down starch, specifically the alpha Glycosidic linkages, found in potatoes. Describe the main functions of carbohydrates in living organisms, and be able to name one or two examples for each function. • Energy Storage • Cell Identify • Raw material source for synthesis • Structure (Example Cellulose and Chitin) • Energy in glucose bonds is transferred to ATP (adenosine triphosphate) for use in cells What characteristic makes certain carbohydrates excellent energy-storage molecules? CHAPTER 5 VOCAB Aldose – A monosaccharide with a carbonyl (C=O) group at the end of the molecule Disaccharide – Carbohydrate of two monosaccharide monomers Hydroxyl group – A hydrogen atom is bonded to an oxygen atom, which in turn is bonded to the carbon skeleton of the organic molecule. Ketose – Monosaccharide with the carbonyl (C=O) group in the middle of molecule Oligosaccharide – Small amount of groups binded Polysaccharide – More than two groups binded Glycolipid – Any lipid molecule that is covalently bonded to one or more carbohydrates Glycoprotein - Any protein with one or more bonded carbohydrates, typically oligosaccharides Chapter 6 Chemical Evolution Theory • Simple compounds formed more complex molecules • Stored energy • Some molecules became components of larger molecules RNA World Hypothesis • Eventually, self- replicating formed • Natural selection formed the most stable and most efficient replicator Transition from molecule to cells? • Lipids formed under early Earth conditions, have have self- a assembled into vesicles & enclosed self-replicating molecules Cell membranes- • Hydrophobic interior, hydrophilic exterior • Forms a selective barrier • Internal environment = chemical reactions What is the distinguishing characteristic of the lipid class of biomolecules? Described by properties (no monomer) Describe the structure of a hydrocarbon. • Made up of hydrogens and carbons Explain the difference between a saturated and an unsaturated fatty acid • Saturated ➢ No double (C=C) bonds ➢ Animal fats, tropical plant oils ➢ Solid at room temperature • Unsaturated ➢ Some C=C bonds (cis configuration) ➢ Plant and fish oils ➢ Liquid at room Temperature What are the three types of lipids discussed in lecture? • Steroids • Phospholipids • Fats Be able to identify the structure and function of each type of lipid. • Steroids ➢ Globular structure with ➢ 4 fused rings, ➢ amphipathic ➢ E.g. Cholesterol: Important component of cell membranes, precursor for other steroids ➢ E.g. Hormones (testosterone and estrogen) • Fats ➢ Triacylglycerols, Triglycerides ➢ Condensation reactions make ester linkages between glycerol and 3 fatty acids ➢ Nonpolar • Phospholipids ➢ Glycerol + 2 hydrophobic chains linked to a phosphate group ➢ Amphipathic ➢ Form cell membranes • Cell Membrane ➢ Amphipathic: spontaneously form micelles or bilayers (vesicles) ➢ Lipid Micelles: Hydrophilic heads interact with water, hydrophobic tails interact with one another, ➢ Lipid Bilayers- Hydrophilic heads interact with water, hydrophobic tails interact with one another, What causes phospholipids to spontaneously form bilayers in aqueous solution? Define selective permeability. • Bilayers are selective permeable • Depends on size and charge of molecule • Most are highly selective • Key characteristics of cells Be familiar with the relative permeability of a cell membrane to various substances What structural and environmental conditions affect membrane permeability? • Degree of H saturation affects permeability • Short and unsaturated hydrocarbon tails give a lipid bilayer HIGHER permeability and fluidity • Long and saturated hydrocarbon tails give a lipid bilayer LOWER permeability and fluidity • Permeability also affected by cholesterol and temperature ➢ Adding cholesterol to membranes decrease the permeability to glycerol. The permeability of all membranes analyzed in the experiment increases with increasing temperature Describe the fluid mosaic model • Mosaic of lipids and proteins • Phospholipids move laterally; proteins move freely throughout the bilayer • Membrane proteins can peripheral or transmembrane • Act as : Channels, carriers, pumps Define and contrast passive transport – simple diffusion, facilitated diffusion, and osmosis – and active transport. Diffusion- Passive movement of solutes of high concentration to an area of low concentration ➢ Spontaneous- no energy required ➢ Keeps going until equilibrium is reached • Passive movement across a membrane- ➢ Substances move down an electrochemical gradient: Based on concentration and electrical charge Osmosis – Spontaneous movement of water down a concentration gradient ➢ Water moves regardless of solute activity Facilitated Diffusion with channel proteins • Allows water to pass through with channel proteins (example: aquaporins) Facilitated Diffusion with carrier proteins Tonicity • The solute concentration across a semi-permeable membrane Hypertonic • High solute, low water concertation Hypotonic • Low solute, high water concentration Isotonic • Solute concentration and water is in equilibrium Which processes require transport proteins? Which require energy (ATP)? Active transport requires energy (ATP) and a protein pump; moves substance against electrochemical gradient Be able to describe the effect each solution has on a cell. CHAPTER 6 VOCAB Amphipathic – Love and hate water. The hydrophilic heads face the fluid. The hydrophobic tails 'hide' in the center Carrier protein – Selectively interacts with a specific molecule to transport it across the membrane Channel protein – provide passageway through membrane for hydrophilic (water-soluble) substances (polar, and charged). Concentration gradient – the varying levels of concentration of a substance on either side of a membrane or in an area Electrochemical gradient – An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consists of two parts, the chemical gradient, or difference in solute concentration across a membrane, and the electrical gradient, or difference in charge across a membrane. GLUT-1 carrier – GLUT1 facilitates the transport of glucose across the plasma membranes of mammalian cells. Integral/transmembrane protein – Any membrane protein that spans the entire lipid bilayer Micelle – an aggregate of molecules in a colloidal solution, such as those formed by detergents. Nonpolar – evenly distributed charge Peripheral protein – Proteins found in the cell membrane which attached to only one side of the membrane. Protein pump – • *the parietal cells release positive hydrogen ions (protons) during HCl production • H+/K+ ATPase enzyme Sodium-potassium pump – The Sodium-Potassium Pump. The process of moving sodium and potassium ions across the cell membrance is an active transport process involving the hydrolysis of ATP to provide the necessary energy. It involves an enzyme referred to as Na+/K+-ATPase. Steroid – stabilize the plasma membrane… any of a large group of fat-soluble organic compounds, as the sterols, bile acids, and sex hormones, most of which have specific physiological action. Triglyceride - ipid molecule made up of one unit of glycerol and three fatty acids, hence the tri- prefix, which means three. A triglyceride looks a little bit like a creature with three tails. The head is glycerol, which is a simple sugar alcohol compound.