Anatomy Exam 1 Quizlet

State the pH values for acidic, neutral, and basic (aka alkaline) solutions

Acidic - 1 to 7 neutral - 7 basic - 7 to 14

Explain the relationship between monomer and polymer

All monomers have the capacity to form chemical bonds to at least two other monomer molecules. Polymers are a class of synthetic substances composed of multiples of simpler units called monomers.

For each of the 4 classes of biomolecules, name the monomer, specific type of covalent bond, polymer, and functions in the human body

Carbohydrates: Monosaccharides = monomer Glycosidic bond = covalent bond connecting monomers Disaccharides = polymer (short length, only 2 units) Polysaccharides = polymer (longer length, can be 3 or more units) provide energy, store energy, build macromolecules, and spare protein and fat for other uses, assisting in lipid metabolism Lipids: Proteins: Amino acid = monomer Peptide bond = covalent bond - made by dehydration synthesis Peptide = polymer (short length) Protein = polymer (longer length) 1.Support (structural proteins) 2.Movement (contractile proteins) 3.Transport (transport (carrier) proteins) 4.Buffering pH 5.Metabolic regulation (enzymes) 6.Coordination and control of metabolism (hormones) 7.Defense (antibodies) Nucleic Acids: Nucleotide = monomer Covalent bond = phosphodiester bond Nucleic acid = polymer

Define the terms organic molecule and inorganic molecule

Organic Molecules Carbon (C) and hydrogen (H) atoms are primary structural components •Forms the majority of the structure, but can include other atoms (O, P, S, N...) •Usually larger size •Usually formed with covalent bonds•Generally found in biological systems (living) Inorganic Molecules •Does not contain C and H atoms as primary structural components •May still contain C and H, but it doesn't form the majority of the structure •Usually smaller size•Usually formed with ionic bonds •Dissociate in water into ions •Generally of geological origin (non-living)

Define the terms chemical reactions, metabolism, anabolism, and catabolism

metabolism = sum of all reactions in an organism anabolism = constructive metabolism catabolism = destructive metabolism chemical reactions = a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.

Define endergonic reactions and exergonic reactions. Which reaction type is each? Identify examples.

Endergonic - forms bonds between atoms and is anabolic exergonic - breaks bonds between atoms and is catabolic

Define the term enzyme and describe a general enzymatic reaction using the terms enzyme, substrate, and product a.Label and describe a graph showing a reaction without an enzyme compared to a reaction with an enzyme (what is each part? What is the same and what is different?)

enzyme: organic catalyst that promotes chemical reactions by lowering activation energy required to begin reaction An enzyme attracts substrates to its active site, catalyzes the chemical reaction by which products are formed, and then allows the products to dissociate (separate from the enzyme surface). The combination formed by an enzyme and its substrates is called the enzyme-substrate complex.

2.Describe in order the levels of organization in the body

Chemical Level atoms -> molecules -> proteins Cellular level Organelles -> individual cell Tissue level Groups of cells working together to perform a specific function(s) Organ level Two or more tissues working together to perform specific function(s) Organ System Level Groups of organs working together to perform a specific function Organism level All body's organ systems work together to maintain life and health of individual

List the 11 major organ systems of the body and their major organs

Circulatory/Cardiovascular - Heart, Blood Vessels, Blood Digestive - Stomach, intestines, liver, pancreas Endocrine - Thyroid gland, adrenal gland Lymphatic/Immune - Thymus, Spleen, Lymph nodes Integumentary - Skin Muscular and Skeletal - skeletal muscles and bone Nervous - Brain, spinal cord Reproduction - ovaries, uterus, testes Respiratory - lungs, airways Urinary - kidneys, bladder

Describe the major functions of each organ system (what does it do?)

Circulatory/Cardiovascular - Transport of materials between all cells of the body Digestive - Conversion of food into particles that can be transported into the body; elimination of wastes Endocrine - Coordination of body function through the synthesis and release of regulatory molecules Lymphatic/Immune - Defense against foreign invaders Integumentary - protection from external environment Muscular and Skeletal - support and movement Nervous - coordination of body function through electrical signals and release of regulatory molecules Reproduction - perpetuation of the species Respiratory - exchange of oxygen and carbon dioxide between internal and external environments Urinary - maintenance of water and solutes in the internal environment; waste removal

Describe major differences in structure and function between DNA and RNA

DNA stores genetic information. It is identical in every single cell of your body •DNA = deoxyribonucleic acid •Determines inherited characteristics•Starts process of protein synthesis •Located inside the nucleus of the cell and NEVER exits and is NEVER degraded •RNA transfers information (from DNA -> RNA -> protein). It is made from a DNA sequence template •RNA = ribonucleic acid •Controls intermediate steps in process of protein synthesis •Synthesized inside the nucleus of the cell and is transported to the cytoplasm to finish protein synthesis. Eventually degraded and nucleotides can be reused.

List the 5 main variables for which the body attempts to maintain homeostasis

Temperature Glucose Levels Ion Concentration pH concentration Fluid Volume

Compare and contrast anaerobic metabolism and aerobic metabolism

Anaerobic metabolism is the creation of energy through the combustion of carbohydrates in the absence of oxygen. ... Aerobic metabolism is the way your body creates energy through the combustion of carbohydrates, amino acids, and fats in the presence of oxygen.

Explain the role of ATP in the cell

ATP functions as the energy currency for cells. It allows the cell to store energy briefly and transport it within the cell to support endergonic chemical reactions. The structure of ATP is that of an RNA nucleotide with three phosphates attached.

Describe the functions of different types of membrane proteins (ex: anchoring proteins, receptor proteins, channels, etc)

1.Anchoring proteins •Attach to cytoskeleton proteins in ICF and extracellular matrix proteins in ECF2.Recognition proteins •Usually glycoproteins •Carbohydrate group extends into ECF and is recognized by immune cells as "self". Abnormal or lack of recognition proteins results in immune cell attack on cell 3.Receptor proteins •Extend into ECF and bind signal molecules in ECF (ex: hormones, neurotransmitters). Are start of signal transduction pathway •Some receptors are in cytoplasm...(not in membrane) 4.Transport proteins •Integral proteins that allows regulated movement of molecules across the membrane (ex: carrier, channel, pump) 5.Enzymes

Describe the structure of cell membranes and explain the 5 functions of membranes.

1.Physical isolation •Barrier that controls permeability 2.Structural support of cell •Cytoskeleton proteins interact with intracellular proteins and with extracellular matrix to hold cell in position •Anchoring proteins 3.Monitors external environment •Receives signals from internal environment •Receives signals from external environment using protein receptors in membrane 4.Identifies cell as "self" to immune system •Recognition proteins extend from membrane have shapes that immune cells can "read" •Abnormal or lack of recognition proteins will result in immune cells attacking the cell 5.Metabolic activities •Enzymes in membrane do reactions in ECF or in ICF

Name the 3 steps in a signal transduction pathway and describe what occurs during each step

1.Reception -- ligand binds + activates receptor on (or inside) receiving cell 2.Transduction -- signal is conveyed across membrane and converted to a form that will prompt a response •Often consists of several steps (each a different protein)•Usually amplifies signal 3.Response -- response is performed by cell

Describe the physiologically important properties of water (what are they and why are they important in function?): high heat capacity, reactivity, lubricant, solubility

High heat capacity: the quantity of heat required to raise the temperature of a substance by 1°C, Water has a high heat capacity because of the hydrogen bonds between water molecules •It requires a large amount of energy input to break enough hydrogen bonds (between water molecules) to raise temperature of water by 1°C Reactivity: •Most chemical reactions in the body occur in aqueous solution •Water can be used as a substrate in reactions •Ex: break bonds (hydrolysis) •Ex: create bonds (dehydration) Lubricant: Lubricants prevent physical damage to surfaces caused by friction •They allow surfaces to smoothly and easily glide past each other Lubricants can help two surfaces remain in physical contact, which may be important for function Universal Solvent: Since water is such a good solvent (it's the universal solvent!), it can dissolve many molecules or ions in itself, forming aqueous solutions Many of the dissolved molecules and ions are involved in different physiological processes within cells and within the whole body •Without these dissolved molecules, several processes would not occur correctly, if at all These dissolved molecules and ions are so necessary for proper function that the body maintains homeostasis of several of them.

Describe the 2 main fluid compartments in the body, including the 3 types of extracellular fluid

Intracellular Fluid - Fluid inside cells Extracellular Fluid - Fluid Outside Cells Interstitial fluid - fluid surrounding tissue cells Blood Plasma Lymph fluid Transcellular Fluid

Compare and contrast tonicity and osmolarity of solutions

Isotonic - extracellular solution has same solute concentration as ICF Hypotonic - extracellular solution has lower solute concentration compared to ICF •Inside cell is high solute/low water •Outside cell is low solute/high water Hypertonic - extracellular solution has higher solute concentration than ICF •Inside is low solute/high water •Outside is high solute/low water Isosmotic - 2 solution have same number of solute particles Hyperosmotic - solution A has more particles than solution B (ex: A is hyperosmotic to B) Hyposmotic - solution A has less particles than solution B (ex: A is hypoosmotic to B)

Describe the relationships between kinetic energy, potential energy, work, and heat

Kinetic Energy - energy of motion Potential Energy - stored energy Work - change in mass or distance (require energy) heat - amount of energy that is transferred from one system to its surroundings because of a temperature difference

Describe the reversible chemical reaction for ATP synthesis and the release of energy from ATP

Like most chemical reactions, the hydrolysis of ATP to ADP is reversible. The reverse reaction combines ADP + Pi to regenerate ATP from ADP. Since ATP hydrolysis releases energy, ATP synthesis must require an input of free energy.

Compare and contrast local control and long distance reflex control mechanisms (what steps? where? what systems are involved?)

Local control •Aka intrinsic control or autoregulation •Localized change occurs in cell or tissue (limited to a small area of body) •Nearby cells detect change in local area and respond •Response limited to local area •Ex: [O2] in a tissue decreases cells lining nearby blood vessel detect it and release chemical signal signal causes muscle around blood vessel to relax (vasodilation) increases blood flow, which brings more oxygen to tissue Long Distance Reflex Control •Aka extrinsic control •Systemic change (body wide) occurs •Nervous system, endocrine system, or both working together communicate long distances to coordinate the responses of multiple organ systems •Response occurs •Has 2 parts: response loop + feedback loop•Ex: increased blood pressure detected by cells in major blood vessels and relayed to a brain region brain (part of nervous system) signals a response by the heart & muscles around blood vessels responses decrease BP

Describe the structure and functions of the various organelles in a typical human cell, including: mitochondria, endoplasmic reticulum (smooth and rough), Golgi apparatus, lysosomes, peroxisomes, nucleus, proteasomes, cytoskeleton (microfilaments, intermediate filaments, microtubules), centrioles, ribosomes (free, fixed), microvilli, cilia, cytoplasm, and cytosol/intracellular fluid

Mitochondria Double membrane, has own ribosomes and circular DNA (due to endosymbiosis) Many exist in a cell. Cells with high metabolic demands have more mitochondria present. Contains many enzymes in its internal fluids and embedded in the inner membrane oEnzymes break down organic molecules using oxygen to produce ATP ("powerhouse of the cell") Endoplasmic reticulum (ER) ER = network of membranous channels extending throughout cytoplasm oForms hollow tubes and cisternae (flattened discs) oRough ER has ribosomes on surface....smooth ER does not Synthesize proteins (rough ER b/c of ribosomes), carbohydrates (smooth ER), lipids (smooth ER) Store synthesized molecules (mostly carbs in smooth ER) Transport molecules to Golgi Detoxify harmful compounds within ER Golgi apparatus Stacks of cisternae (flattened discs) that have chambers Store, modify, and package products for secretion Creates lysozomes by packaging digestive enzymes inside a vesicle Renews or modifies plasma membrane by donating its own membrane Lysosome Vesicles formed by Golgi apparatus containing digestive enzymes Lysosome fuses with a damaged organelle or an endocytic vesicle to break down extracellular molecules. Pieces are reused or removed by exocytosis Peroxisome Vesicle containing enzymes that digest fatty acids and amino acids. Produces hydrogen peroxide as a reaction product (hence its name), but it also contains enzymes that immediately break down hydrogen peroxide (H2O2) to prevent it from damaging the cell Break down fats Nucleus Nucleus stores genetic information coding for all cell's contents oDNA stored as chromatin...only condenses to chromosomes during mitosis oSite of transcription Proteasome Small hollow cylinder containing proteases (enzymes that digest proteins) Present in cytoplasm Digest damaged, abnormal, or old intracellular proteins. Pieces can be resused or exocytosed. CCyto General functions: structural support of cell, organizes location of cell contents 3 types of cytoskeletal elements: 1. Microfilaments (actin protein) a.Actin proteins arranged in double helix shape b. Thinnest diameter c.Anchor cytoskeleton to integral proteins in membraned. Serve as tracks for myosin protein i. Contraction inside cell (ex: cleavage furrow during mitosis, muscle cell contraction) ii. Motility of entire cell iii. Move vesicles and organelles inside cell (myosin "walks" along actin tracks) 2. Intermediate filaments a.Strengthen cell and help maintain its shape b. Stabilize the position of organelles c.Stabilize cell's position within the tissue (through attachments to plasma membrane) d. Some cells have specialized functions for intermediate filaments i. Ex: keratin in skin (strength, resist stretching) 3. Microtubules (tubulin protein) a.Most responsible for giving a cell its shape and strength b. Can change shape of cell and aid in individual cell's movement c.Most responsible for anchoring organelles. Can also transport organelles around cell d. Form structural components of other organelles (cilia and centrioles) i. Cilia - present on some cells. Long, slender extension of plasma membrane. Some cilium used for sensing local environment, some cilium used to rhythmically sweep/brush fluid along its surface to move fluid + materials in it ii. Centrioles - pair of cylinders inside the centrosome. During mitosis, centrioles form microtubules that move chromosomes. Microvilli Some cells. Small finger-like projections of plasma membrane containing cytoskeletal elements. Increases surface area of cell to maximize absorption of material Cytoplasm Consists of cytosol (intracellular fluid/ICF = water + dissolved solutes) + organelles + inclusions Cytosol has many functionsoContains and transports molecules within the cell oAids in maintaining cell's tonicity oSite of many organelles and many enzymatic reactions Ribosome Mixture of rRNA and protein. 2 subunits that attach only during protein synthesis/translation. Free ribosomes present in cytosol Fixed ribosomes attached to surface of rough ER Performs protein synthesis/translation

Compare and contrast negative feedback and positive feedback. Identify examples of each

Negative Feedback Loop •Used by most long-distance reflex loops to maintain homeostasis b/c it keeps variable near its setpoint...which keeps variable relatively constant •Negative feedback loops occur when the response opposes or removes the stimulus •Basically the response returns the variable to set range.....and negative feedback shuts off the response loop •Negative feedback loops can restore set range, but they CANNOT prevent the initial change (it's related to the response) Positive Feedback Loop •Used by only a few reflex pathways b/c it is NOT homeostatic (it doesn't keep variable near setpoint) •Positive feedback loops occur when the response reinforces the stimulus •The response sends the variable even farther from its setpoint, which causes a cycle of ever-increasing response... •System is temporarily out of control •An outside factor or event is required to stop the response loop

Compare and contrast polar covalent bonds and nonpolar covalent bonds. a.Include the molecular basis of polarity (what makes it polar?) and the role of polarity in molecular interactions (why is it important that polar molecules interact this way?)

Non-Polar Covalent Bonds •Electrons are shared equally by both atoms •Electrons spend equal time orbiting both nuclei •Result is a uniform distribution of electric charge (so it does NOT have electrical charge) •Ex: C-C bond Polar Covalent Bonds •Electrons are shared unequally •Electrons spend more time orbiting one atom •Result is uneven distribution of electric charge b/c one atom has a partial negative charge while the other atom has a partial positive charge (aka it is a polar molecule) •Ex: O-H bond in a water molecule

Describe factors that can affect enzyme activity: pH, temperature, enzyme concentration, substrate concentration

The amount of substrate and the amount of enzyme present •Affects how many enzymes are available to work + how much "work" is available to do Temperature (of the environment) •Affects shape of the enzyme/active site pH (of the environment) •Affects shape of the enzyme/active site

Define the terms solution, solute, solvent, colloid, suspension, dissociation, and ionization

Solute = substance that is dissolved solution = is a special type of homogeneous mixture composed of two or more substances solvent = substance that does the dissolving Colloid = A solution containing dispersed proteins or other large molecules, Particles will remain in solution indefinitely Suspension = Contains large molecules in solution, but if undisturbed, its particles will settle out of solution due to gravity ionization = is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes dissociation = is a general process in which molecules separate or split into other things such as atoms, ions, or radicals, usually in a reversible manner.

List the steps in a homeostatic response pathway, beginning with a stimulus and ending with the response

Stimulus = change in regulated variable in ECF Sensor or Receptor = detects a specific stimulus. Many different types in body, each specialized to detect one type of stimulus Input Signal = relays info about stimulus to integrating center Integrating Center = compares input signal with the setpoint. Often receives and integrates multiple input signals. Often in CNS. Can send multiple output signals Output Signal = signal that travels from Integrating Center to Target. Can be electrical (neuron) and/or chemical (hormone) Target or Effector = cell or tissue that carries out appropriate activity to bring variable back within normal limits Response = activity performed by Target

Compare and contrast strong acids (or bases) and weak acids (or bases)

Strong acids and strong bases completely dissociate in solution •They dramatically change the pH (adding or removing H+) •The dissociation reaction occurs in only one direction (i.e. not reversible) •Example: HCl -> H+ and Cl- •Example: NaOH -> Na+ and OH- •Weak acids and weak bases do NOT completely dissociate in solution •Many of the "starting" molecule remains intact in the solution at all times •They do NOT dramatically change the pH b/c the dissociation reaction is easily reversible HA <-> H+ and A- •Example: H2CO3 <-> H+ and CO3- •They serve as buffers to help maintain pH homeostasis

Summarize how the body uses buffers and 2 major organ systems to maintain pH homeostasis a.Include names & locations of the buffer systems, the organ systems, and how buffers influence pH of body fluids

The human body has 3 compensatory mechanisms to handle most variations in pH (and keep us within homeostatic set range) 1.Ventilation by the respiratory system 2.Excretion in the urine by the urinary system 3.Buffers in the body fluids Ventilation by the respiratory system •Ventilation = breathing in and out •Removes CO2 gas from body. CO2 is involved in one of the bicarbonate buffer system in the plasmaCO2 + H2O <-> H+ + HCO3- •Altering ventilation will change the [CO2] in the body, which affects the [H+] in the blood •Can either cause pH imbalances or fix them Excretion in urine by the urinary system •Kidneys create urine and can affect pH by changing the amount of H+ or the amount of HCO3- (bicarbonate ion) it excretes into urine or reabsorbs into plasma Buffer systems in the plasma 1.Bicarbonate buffer system - uses bicarbonate ion (HCO3-) 2.Phosphate buffer system - uses phosphate ion (HPO42-) 3.Various protein buffer systems •Hemoglobin protein (in red blood cells) •Plasma proteins (in plasma of blood) - ex: albumin protein •Proteins or amino acids inside all cells

Explain the importance of maintaining pH homeostasis in the body (why is it important? what occurs if it is not maintained?)

The reason as for why pH homeostasis is so important is due to the fact that because H+ has no valence electrons it will bind to ANYTHING which can disrupt the molecules (including the enzymes) in your body. It would bind to the molecule, changing its 3D structure and function of the molecule in the process which could be detrimental to maintaining homeostasis. If the 3D structure of an enzyme changes then it disrupts the binding of the active site so the substrate cannot bind, which means the enzyme can't catalyze the reaction.

1. Define anatomy and physiology as well as the subcategories of each

anatomy - the study of body structures and their relationships to each other gross anatomy - aka macroscopic anatomystudy of large structures that can be viewed WITHOUT magnification--includes several subtypes Surface Anatomy - type of gross anatomy study of the body's surface, especially as it is related to deeper structures Regional Anatomy - type of gross anatomystudy of specific areas (regions) of body, especially the spatial relationships between areas Sectional Anatomy - type of gross anatomystudy of cross-sections of a tissue, organ, or body--cross-sections are made by cutting along one of the planes (we learned in lab) Systemic Anatomy - type of gross anatomystudy of organ systems Clinical Anatomy - type of gross anatomystudy of subspecialites important in clinical (medical) practice Developmental Anatomy - type of gross anatomystudy of changes occurring during development from embryo to adult Embryology - subtype of developmental anatomystudy of changes occurring during first 2 months of development (in embryo) microscopic anatomy - study of small structures that can only be viewed WITH magnification Histology - type of microscopic anatomystudy of tissues Cytology - type of microscopic anatomystudy of internal structures of individual cells Physiology - the study of normal functions are performed in living organisms Cell physiology - functions of cells (within 1 cell & between multiple cells) Organ physiology - function of specific organs Systemic physiology - functions of specific organ systems Pathological physiology (aka pathophysiology) - functions of organs or organ systems in a disease state

Describe the 4 physiologically important types of reactions in the body: decomposition, synthesis, exchange, reversible

decomposition - breaks bonds synthesis - forms bonds exchange - Exchange reactions involve parts of the reacting molecules shuffled around to produce new products reversible - chemical reaction that occurs in forward and reverse directions

Define hydrolysis reactions and dehydration reactions. Which reaction type is each? Identify examples.

hyrdrolysis - a type of decomposition reaction involving water dehydration - a type of synthesis reaction involving water

Define the law of mass balance and relate it to body homeostasis

law of mass balance. if the amount of a substance in the body is to remain constant, any gain must be offset by an equal loss. •The body has a certain load (amount) for each substance •If we gain more of it, we will need to remove an equal amount •Ex: you drink a lot of water you urinate a lot more (which is mostly water) •The body is maintaining a fairly consistent load, which aids in maintaining homeostasis •Too much or too little of a substance usually causes problems...

Define the terms pH, acid, base, buffer, and salt

pH is a scale used to specify the acidity or basicity of an aqueous solution. Acidic solutions are measured to have lower pH values than basic or alkaline solutions Acid: A solute that dissociates into H+ and anions Base: Solute that dissociates into OH- and cations Buffer: compounds that minimize changes to pH by adding or removing H+ from solution. Usually consists of 2 parts: 1.Weak acid - proton donor that reacts with bases (it donates H+ to bind bases in solution) 2.Weak base - proton acceptor that reacts with acids (it binds H+ in solution) Salt: solutes that dissociate into cations and anions other than H+ and OH-

Compare and contrast the terms free radical, radioisotope, and electrolyte

radioisotopes: isotopes with unstable nuclei that break down and give off radiation (energy from moving subatomic particles) •Radiation can damage molecules•Weakly radioactive isotopes can be used in diagnostic imaging because they aren't naturally found in the body, so we can detect their presence. •Imaging •Tracers/labeling for imaging •Strongly radioactive isotopes can also be used to intentionally kill cells (ex: cancer treatments) •...but they kill all cells, so delivery must be very focused Free radicals: unstable molecules with an unpaired electron •Electrons are most stable in pairs....meaning unpaired electrons "want" to steal a single electron from another atom to create a stable pair •Similar to the octet rule, right? •However, stealing a single electron from another atom will cause it to become a free radical.....it's a chain reaction •Stealing electrons from other atoms can disrupt interactions, thus damaging molecule structure•Free radicals are created during natural metabolism OR through exposure to radiation (energy in wave form) •Antioxidants = molecules that can take or give up an electron without becoming a free radical •Free radicals are thought to contribute to aging and the development of certain diseases •Electrolyte = ion dissolved in water that produces an electrically conducting solution •Electrical charges on ions can conduct electricity!!!!!! •Many electrolytes have important physiological roles in the human body •Examples: Na+, K+, Ca2+ ---- all are involved in neuron signals and muscle contraction

Describe these 3 types of chemical interactions between atoms: covalent bond, ionic bond, and hydrogen bond. You should include: a.How the interaction forms b.How the interaction behaves in an aqueous solution (aka its solubility) and explain why its chemical structures makes it behave this way c.Examples of these bonds in molecules within the human body

•Covalent bond: chemical bond formed when two atoms share electrons in their valence shells •One electron is provided by each atom (making a pair of electrons) •The shared pair of electrons orbit the nuclei of both atoms •Atoms share electrons to fill their valence shell •Covalent bonds are strong •Difficult to break (often require enzyme to break it) •Forms molecules or compounds •Ionic bonds: chemical bond formed between two oppositely charged ions •Ion = atom that has either gained or lost electrons in its valence shell, which forms an electrical charge (positive or negative) •In an ionic bond, one atom (the electron donor) loses one or more electrons, becoming a cation with a positive (+) charge •The other atom (the electron acceptor) gains the same electron or electrons and becomes an anion with a negative (-) charge •The ionic bond is the attraction between the opposite electrical charges (positive/negative) •Ionic bonds are strong •But they can be broken by water, so they are not quite as strong as covalent bonds •Ionic bonds form compounds •Though some compounds may have covalent bonds... •Hydrogen bond: weak electricalattractionformed between two adjacent polar molecules •polar molecules have unequal sharing of electrons in covalent bond, which forms ends (aka poles) with slight/partial charges •One polar molecule will have partial positive charge (fewer e- there) on a hydrogen atom •The other polar molecule will have partial negative charge (more e- there) on an electronegative atom like O, F, N •ALWAYS involves H and electronegative atom •Weak electrical attraction = hydrogen bond •Hydrogen bonds do NOT form molecules or compounds •No electrons are gained, lost, or shared •It is weak electrical attraction •It is very easily formed and broken...usually by distance between the participating molecules •Individual hydrogen bonds are weakand easily broken •...but many hydrogen bonds can form a stronginteraction between two molecules •In this way, hydrogen bonds play an important role in many biological systems •Ex: H bonds hold 2 strands of DNA together

Explain what makes a membrane a semipermeable barrier. What types of molecules can diffuse across the membrane and what types cannot?

•Hydrophobic molecules are not charged, so they can directly cross through the phospholipid bilayer b/c they can interact with hydrophobic fatty acid tails in center of membrane •Hydrophilic molecules are charged, so they CANNOT directly cross membrane b/c they CANNOT interact with hydrophobic fatty acid tails in center of membrane

Describe the 4 levels of protein structure and the importance of protein shape for function

•Primary (1°) structure Primary structure = sequence of amino acids along the length of a single peptide •Peptide bonds connect individual amino acids •The order of the amino acids is encoded by order of nucleic acids (DNA, RNA)... •Secondary (2°) structure •Secondary structure = hydrogen bonds form between functional groups in peptide backbone (amino, carboxyl) •Forms alpha helix (spiral) or beta sheet (pleats) •Tertiary (3°) structure •Tertiary structure = secondary structure folds into unique 3D shape because of these factors: 1.R group interacting with another R group •Can form ionic bonds, hydrogen bonds, or disulfide bonds •Disulfide bond = covalent bond between 2 sulfhydryl groups (-SH) 2.R group interacting with water (in the aqueous solution surrounding the protein) •Hydrophilic R groups can interact with water. They remain on the surface of the folded protein •Hydrophobic R groups cannot interact with water. They are buried in the interior of the folded protein. •Quaternary (4°) structure multiple protein subunits interact to become a protein complex •Each peptide subunit has its tertiary structure •Submits interact with multiple hydrogen bonds between their folded surfaces