UNIT 1: WELLNESS AND HOMEOSTASIS WHAT IS THE DIFFERENCE BETWEEN HEALTH AND WELLNESS? 5 FACTORS OF WELL-BEING • PHYSICAL • EMOTIONAL • SPIRITUAL • INTELLECTUAL • SOCIAL WHAT IS BIOLOGY? LIVING THINGS • BIOLOGY IS THE STUDY OF __________________________ LIFE “OLOGY”= A SUBJECT OF ______________ STUDY • “BIO” = _______, • BROAD DISCIPLINE DUE TO THE WIDE VARIETY OF ORGANISMS ON THE PLANET HUMAN • IN THIS COURSE, YOU WILL LEARN MORE ABOUT THE _____________ ORGANISM. YOU WILL ANATOMY STUDY THE STRUCTURE OF THE HUMAN BODY (________________) AND ALSO HOW THE PHYSIOLOGY HUMAN BODY WORKS (________________). THESE TWO AREAS—STRUCTURE AND FUNCTION—ARE CLOSELY RELATED. FOUNDATIONS OF BIOLOGY CELLS ARE THE BASIC UNIT OF LIFE. • __________ GENES ARE THE BASIC UNITS FOR PASSING TRAITS FROM PARENT TO OFFSPRING. • ___________ EVOLUTION • _______________ HAS LED TO THE GREAT DIVERSITY OF SPECIES ON EARTH. MAINTAIN • LIVING THINGS ________________ THE ENVIRONMENT WITHIN THEIR CELLS AND BODIES. ENERGY • LIVING THINGS HAVE THE ABILITY TO ACQUIRE AND TRANSFORM _______________. LEVELS OF ORGANIZATION MOLECULES OF LIFE • ALL LIFE ON EARTH IS BUILT FROM FOUR DIFFERENT TYPES OF MOLECULES. THESE MOLECULES ARE OFTEN REFERRED TO AS BIOMOLECULES. CARBOHYDRATES • ______________________ LIPIDS • ______________________ PROTEINS • ______________________ NUCLEIC ACIDS • ______________________ • WITHOUT THESE FOUR MOLECULES, A CELL AND ORGANISM WOULD NOT BE ABLE TO LIVE. WELLNESS • WELLNESS IS NOT THE SAME AS HEALTH. PHYSICAL • HEALTH GENERALLY REFERS ONLY TO THE _______________ Physical WELL-BEING OF AN INDIVIDUAL • WELLNESS REFERS TO THE MULTIDIMENSIONAL INTERRELATIONSHIP _______________________ BETWEEN THE FIVE Social Emotional FACTORS OF WELL-BEING: Intellectual Spiritual HOMEOSTASIS • THE BODY’S ATTEMPT TO MAINTAIN A STABLE INTERNAL ENVIRONMENT • EX: WHAT DOES THE BODY DO WHEN... YOU SHIVER • IT’S -30°C OUTSIDE? _________________________________ YOU SWEAT • IT’S +35°C OUTSIDE? ________________________________ YOU SWEAT, BREATHE HEAVILY, • YOU GO FOR A RUN? __________________________________ HEART RATE INCREASES HOMEOSTASIS • IN ORDER TO FUNCTION PROPERLY, HOMEOSTATIC MECHANISMS ARE REQUIRED TO: GASES 1. REGULATE RESPIRATORY ____________ (E.G. OXYGEN) SALT BALANCE (E.G. ELECTROLYTES) WATER AND _______ 2. MAINTAIN ________ ENERGY / __________ NUTRIENT SUPPLY (E.G. BLOOD SUGAR) 3. REGULATE ___________ TEMPERATURE 4. MAINTAIN CONSTANT BODY _________________ PATHOGENS 5. PROTECT AGAINST _________________ REPAIRS 6. MAKE ______________ WHEN INJURED QUICK RESEARCH • BODY TEMPERATURE • BLOOD PH • RESTING HEART RATE • BLOOD PRESSURE • BLOOD SUGAR (FASTING) DYNAMIC EQUILIBRIUM DYNAMIC EQUILIBRIUM • HOMEOSTASIS IS OFTEN REFERRED TO AS A ____________________________WHICH IS A MECHANISM TO ENSURE THAT ALL BODY SYSTEMS FUNCTION WITHIN AN ACCEPTABLE RANGE TO SUSTAIN LIFE. • DYNAMIC EQUILIBRIUM A CONDITION THAT REMAINS STABLE WITHIN FLUCTUATING _________________ LIMITS. SET POINTS • THE BODY WORKS BEST AT SPECIFIC ________________ (TEMPERATURE 7.4 ETC.) 37 ____°C, BLOOD PH NEAR ______, NEGATIVE FEEDBACK MECHANISMS OPPOSITE DIRECTION TO THE • A FEEDBACK IN WHICH THE SYSTEM RESPONDS IN AN _____________ DISTURBANCE. REVERSE THE CHANGE THAT IS HAPPENING. • YOUR BODY RESPONDS IN SUCH A WAY TO _________ • NEGATIVE FEEDBACK IS THE PRIMARY HOMEOSTATIC MECHANISM THAT OUR BODIES USE. FEEDBACK: A RESPONSE WITHIN A SYSTEM THAT AFFECTS THE CONTINUED ACTIVITY OF THAT SYSTEM NEGATIVE FEEDBACK MECHANISMS • INVOLVES 3 COMPONENTS: SENSOR/RECEPTOR RECEIVES INFORMATION/STIMULUS ABOUT A CHANGE IN THE • ___________________: ENVIRONMENT, SENDS INFORMATION TO CONTROL CENTRE CONTROL CENTRE • ____________________: DETERMINES AN APPROPRIATE RESPONSE TO THE STIMULUS AND SENDS SIGNAL TO EFFECTOR EFFECTOR • ________________: CREATES A RESPONSE THAT CHANGES CONDITIONS IN THE INTERNAL ENVIRONMENT TO RESTORE BALANCE SENSOR CONTROL CENTRE EFFECTOR Normal condition __________ Example: Temperature in house set to 20°C. Internal house temperature drops to 17°C. Thermostat detects drop in temperature. Thermostat turns on furnace. Furnace starts and begins to warm house. Temperature returns to 20°C. Change ___________ ___________ Change ___________ ___________ Effector ___________ ___________ Sensor ___________ ___________ Control Centre ___________ ___________ THERMOREGULATION • THE MAINTENANCE OF A CONSTANT BODY TEMPERATURE ________________ (37°C IN HUMANS) HEAT STRESS INCREASE IN BODY • THERMORECEPTORS DETECT AN ___________ CONTROL CENTRE TEMPERATURE, SEND MESSAGE TO __________________ SWEAT GLANDS TO INITIATE • HYPOTHALAMUS SIGNALS TO THE ______ ________. SWEATING • EVAPORATION OF THE SWEAT OFF THE SKIN CAUSES COOLING. HEAT STRESS BLOOD • THE HYPOTHALAMUS ALSO SENDS MESSAGE TO _________ VASODILATION VESSELS IN THE SKIN CAUSING THEM TO _________. DILATE • DILATION ALLOWS FOR MORE BLOOD FLOW TO THE SKIN. • HEAT FROM THE BLOOD IS LOST TO THE SKIN SO BLOOD CAN RETURN TO CORE OF YOUR BODY & COOL THE INTERNAL ORGANS. COLD STRESS DECREASE IN BODY TEMPERATURE, • THERMORECEPTORS DETECT A __________ SEND MESSAGE TO HYPOTHALAMUS • HYPOTHALAMUS SENDS A MESSAGE VIA THE NERVES TO THE MUSCLES MAKING THEM CONTRACT CAUSING SKELETAL _________ SHIVERING _____________ HEAT • MOVEMENT OR SHIVERING GENERATES __________ COLD STRESS • THE HYPOTHALAMUS ALSO SENDS MESSAGE TO BLOOD VESSELS CONSTRICT IN THE SKIN CAUSING THEM TO ____________. VASOCONSTRICTION • REDUCES HEAT LOSS FROM THE SKIN AND RETAINS HEAT IN THE BODY. • SMOOTH MUSCLES AROUND HAIR FOLLICLES CONTRACT CAUSING THE HAIR TO “STAND ON END” TRAPPING WARM AIR. IN THERMOREGULATION, WHAT IS/ARE THE: • SENSORS/RECEPTORS? THERMORECEPTORS IN SKIN ________________________________________ • CONTROL CENTRE? HYPOTHALAMUS (BRAIN) _________________________________________ • EFFECTORS? SWEAT GLANDS, HAIR FOLLICLES, BLOOD VESSELS, MUSCLES _______________________________________________ OSMOREGULATION WATER BALANCE • THE MAINTENANCE OF A CONSTANT _______________________ IN THE BODY. • THE HYPOTHALAMUS CONTROLS (WITH HORMONES) INCREASED ABSORPTION OF WATER AS WELL AS THIRST. • WE TAKE IN MOST OF OUR WATER FROM FOOD OR DRINK, AND WE URINATING DEFACATING AND LOSE WATER BY _____________, ___________, EVAPORATION (BREATHING AND SWEATING). _______________ OSMOREGULATION • REGULATION OF WATER IS IMPORTANT BECAUSE OUR CELLS CANNOT SURVIVE A NET GAIN OR LOSS OF WATER. THIRST • A LOSS OF 1% OF OUR BODY FLUID CAUSES _________ • A LOSS OF 5% OF OUR BODY FLUID RESULTS IN EXTREME PAIN OR COLLAPSE _______ DEATH • A LOSS OF 10% OF OUR BODY FLUID CAN CAUSE ___________ IN OSMOREGULATION, WHAT ARE/IS THE: • SENSORS/RECEPTORS? OSMORECEPTORS IN HYPOTHALAMUS ________________________________________ • CONTROL CENTRE? PITUITARY GLAND (BRAIN) _________________________________________ • EFFECTORS? KIDNEYS _______________________________________________ WASTE MANAGEMENT • THE ABILITY OF THE BODY TO RID ITSELF OF HARMFUL WASTE ___________. KIDNEYS ________, LIVER _______, SKIN LUNGS ________, • THE _________, AND STOMACH _____________ ARE INVOLVED IN THE ELIMINATION OF VARIOUS WASTE PRODUCTS. • THIS WILL BE COVERED FURTHER IN A LATER UNIT. • HTTPS://WWW.YOUTUBE.COM/WATCH?V=IZ0Q9NTZCW4 • GO OVER THERMOREGULATION LOOPS • CREATE 2 FEEDBACK LOOPS FOR OSMOREGULATION (TOO MUCH WATER, TOO LITTLE WATER) LIFE PROCESSES • COMPLEX ORGANISMS NEED TO CARRY OUT THE FOLLOWING SIX LIFE PROCESSES: FOOD • OBTAIN _________ ENERGY • CONVERT __________ WASTES • ELIMINATE __________ REPRODUCE • _____________ GROW & ___________ REPAIR • ________ •TRANSPORT ____________ SUBSTANCES ALL OF THESE LIFE PROCESSES • INDIVIDUAL CELLS MUST ALSO CARRY OUT _______ THE CELL THEORY • THE MODERN CELL THEORY HAS THREE MAIN PRINCIPLES: CELLS 1. ALL ORGANISMS ARE COMPOSED OF ONE OR MORE __________. BASIC UNIT 2. CELLS ARE THE __________________ OF STRUCTURE AND ORGANIZATION OF ORGANISMS. PRE-EXISTING CELLS. 3. CELLS ARISE BY THE DIVISION OF ________________ TWO BASIC CELL TYPES PROKARYOTIC • 1. ______________________ CELLS • NO TRUE NUCLEUS • LACKS MEMBRANE-BOUND ORGANELLES BACTERIA • E.G. _________________ TWO BASIC CELL TYPES EUKARYOTIC • 2. ____________________________________ CELLS NUCLEUS • HAVE A TRUE ____________________ • CONTAIN MEMBRANE-BOUND ORGANELLES, THEREFORE, CELL FUNCTIONS ARE SEPARATED INTO DISTINCT COMPARTMENTS AND CAN BE CARRIED OUT SIMULTANEOUSLY. • E.G. FUNGUS, PLANTS, ANIMALS CELL/PLASMA MEMBRANE • ALL LIVING CELLS POSSESS SUCH A MEMBRANE WHICH SERVES AS ITS BOUNDARY WITH THE EXTERNAL ENVIRONMENT. SELECTIVELY PERMEABLE OR ________SEMI • ________________ PERMEABLE • THIS MEANS IT ALLOW THE PASSAGE OF CERTAIN MOLECULES WHILE BLOCKING OTHERS FOUR MAIN FUNCTIONS OF CELL MEMBRANE SURROUNDS 1. THIN, MOLECULAR LAYER THAT _______________ ALL LIVING CELLS SEPARATES 2. _________________ THE CELL FROM ITS EXTERNAL ENVIRONMENT 3. ______________ THE CELL FROM CHANGES IN THE CHEMICAL PROTECTS AND PHYSICAL ENVIRONMENT FOUR MAIN FUNCTIONS OF CELL MEMBRANE INTO OUT 4. REGULATES THE TRAFFIC OF MOLECULES _________ AND ______ OF THE CELL: UNWANTED MATERIALS FROM ENTERING • PREVENTS ______________ • TRANSPORTS RAW MATERIALS INTO CELL WASTES • TRANSPORTS MANUFACTURED PRODUCTS AND ____________ OUT OF CELL • PREVENTS ESCAPE OF MATTER NEEDED TO PERFORM CELLULAR FUNCTIONS CELL MEMBRANE • COMPOSED PRIMARILY OF TWO TYPES OF MOLECULES: LIPIDS • ______________ – FATTY & OILY MOLECULES PROTEINS • ______________ PHOSPHILIPID BILAYER STRUCTURE • TWO SHEETS OF LIPIDS (PHOSPHOLIPIDS), EACH SHEET A SINGLE MOLECULE THICK. • THEY CONTAIN A PHOSPHATE GROUP, HEAD CALLED THE ___________, AND TWO CHAINS OF FATTY ACID, CALLED THE TAILS ____________. LOVING • HYDROPHILIC = WATER _____________ • HYDROPHOBIC = WATER FEARING _____________ FLUID MOSAIC MODEL • THE CELL MEMBRANE IS COMPOSED OF A DOUBLE LAYER PHOSPHOLIPIDS (BILAYER) OF ____________________ INTO WHICH PROTEIN ________________ MOLECULES ARE EMBEDDED. • PROTEINS ARE RESPONSIBLE FOR: TRANSPORTING SUBSTANCES ACROSS THE MEMBRANE • ___________________ COMMUNICATION BETWEEN CELLS • AIDING ____________________ CHEMICAL • CARRYING OUT __________________ REACTIONS FLUID MOSAIC MODEL FLEXIBLE • IT IS “FLUID” BECAUSE IT IS __________________ – THE PHOSPHOLIPIDS AND PROTEINS MOVE WITHIN THE MEMBRANE • IT IS “MOSAIC” BECAUSE THE PROTEINS CREATE A “PATTERN” ‘_______________ ON THE MEMBRANE SURFACE THE CELL MEMBRANE AND HOMEOSTASIS CONSTANT FOR IT • CONDITIONS INSIDE EVERY CELL MUST REMAIN NEARLY ________________ TO KEEP PERFORMING ITS LIFE FUNCTIONS CELL MEMBRANE • THE ________________________ IS RESPONSIBLE FOR MAINTAINING HOMEOSTASIS. SELECTIVE PERMEABILITY • DUE TO _________________________________, THE CELL MEMBRANE CONTROLS WHAT GOES IN AND OUT OF THE CELL • IN A MULTICELLULAR ORGANISM, EVERY CELL IS BATHED IN A THIN LAYER OF EXTRACELLULAR ____________________ FLUID, CONSISTING OF WATER AND OTHER MATERIALS • CONTAINS SUBSTANCES THAT CELLS NEED AND WASTE THAT CELLS HAVE DISCARDED VOCABULARY QUIZ-MONDAY Homeostasis Negative feedback Osmoregulation Wellness sensor/receptor Semi-permeable Lipid Control centre Phospholipid bilayer Carbohydrate Effector Extracellular fluid Protein Thermoregulation Passive transport Nucleic acid Vasodilation Diffusion Negative Vasoconstriction Concentration gradient Isotonic Active transport Osmosis Hypertonic Hypotonic PASSIVE TRANSPORT ENERGY DOWN CONCENTRATION • DOES NOT REQUIRE _____________. MOVES ____________ GRADIENT. 1. DIFFUSION • MOVEMENT OF MOLECULES (E.G. OXYGEN) FROM A REGION IN WHICH THEY ARE HIGHLY CONCENTRATED TO A REGION IN WHICH THEY ARE LESS CONCENTRATED 1. DIFFUSION • MOLECULES MOVE ACROSS THE MEMBRANE THROUGH PORES EQUAL • CONTINUES UNTIL THE MOLECULES INVOLVED ARE ______________ DISTRIBUTED THROUGHOUT THE SYSTEM ON BOTH SIDES OF THE MEMBRANE. EQUILIBRIUM THE SYSTEM IS THEN SAID TO BE IN _________________________ 2. OSMOSIS WATER • MOVEMENT OF ________________ MOLECULES FROM A REGION OF HIGHER CONCENTRATION TO A REGION OF LOWER CONCENTRATION. • WATER WILL MOVE TOWARD A HIGH CONCENTRATION OF SOLUTE AND HENCE A LOWER CONCENTRATION OF WATER. 2. OSMOSIS ISOTONIC __________________ CONDITIONS: THERE IS THE SAME SOLUTE CONCENTRATION INSIDE AND OUTSIDE THE CELL. EQUAL AMOUNTS OF WATER MOVE IN AND OUT OF THE CELL. 2. OSMOSIS • __________________ CONDITIONS: SOLUTION HAS LESS SOLUTE THAN HYPOTONIC THE CELL. A CELL PLACED IN THIS SOLUTION WILL TAKE UP WATER AND SWELL. 2. OSMOSIS HYPERTONIC CONDITIONS: SOLUTION HAS MORE SOLUTE THAN • __________________ THE CELL. A CELL PLACED IN THIS SOLUTION WILL GIVE UP WATER AND SHRINK. 3. FACILITATED DIFFUSION • MOVEMENT OF MOLECULES TOO ____________ TO PASS THROUGH THE LIPID LARGE GLUCOSE BILAYER ON THEIR OWN (E.G. _________________). • MOVEMENT IS FROM A REGION OF HIGH CONCENTRATION TO LOW PROTEINS CONCENTRATION AND IS ASSISTED BY ________________ ACTIVE TRANSPORT ENERGY (ATP) • REQUIRES ADDITIONAL _______________________. MOVES ______ UP CONCENTRATION GRADIENT. • CARRIES MOLECULES FROM AREAS OF LOW CONCENTRATION TO HIGH TRANSPORT CONCENTRATION USING ______________________ PROTEINS IN THE CELL MEMBRANE ACTIVE TRANSPORT • 1. PROTEIN PUMPS • PERMITS THE CELL TO COLLECT CERTAIN SUBSTANCES IN HIGH CONCENTRATION (E.G. NUTRIENTS) • ALLOWS CELLS TO GET RID OF ______________ WASTE SUBSTANCES TOXIC 2. ENDOCYTOSIS/EXOCYTOSIS • SOMETIMES SUBSTANCES ARE TOO LARGE TO MOVE THROUGH THE LIPID LAYER OR THROUGH PROTEIN CARRIERS. Exocytosis: a vesicle forms around the unwanted substances and fuses with the cell membrane; the contents are secreted into the extracellular fluid Endocytosis: cell membrane folds inward, trapping and enclosing substances from the extracellular fluid FACTORS THAT AFFECT MOVEMENT ACROSS THE CELL MEMBRANE SIZE SMALL MOLECULES CAN MOVE THROUGH THE CELL • ________: MEMBRANE BY DIFFUSION. LARGER MOLECULES CANNOT MOVE THROUGH BY DIFFUSION, EVEN IF THERE IS A STRONG CONCENTRATION GRADIENT. FACTORS THAT AFFECT MOVEMENT ACROSS THE CELL MEMBRANE POLARITY • _______________: DETERMINES HOW EASILY THE MOLECULE CAN PASS THROUGH THE CELL MEMBRANE. • NON-POLAR TAILS REPEL CHARGED MOLECULES OR IONS (CHARGED ATOMS) • IONS REQUIRE CHANNELS FACTORS THAT AFFECT MOVEMENT ACROSS THE CELL MEMBRANE TEMPERATURE MOLECULES IN A SYSTEM AT A _____________ HIGHER • ___________________: ENERGY TEMPERATURE WILL HAVE MORE _________________ AND WILL MOVE AND FASTER DIFFUSE ________________. FACTORS THAT AFFECT MOVEMENT ACROSS THE CELL MEMBRANE CONCENTRATION THE _______________ HIGHER • ______________________: THE CONCENTRATION FASTER GRADIENT, THE _____________________ THE RATE OF DIFFUSION FACTORS THAT AFFECT MOVEMENT ACROSS THE CELL MEMBRANE SURFACE AREA LARGER • ______________________________: THE __________________ THE AREA OVER WHICH DIFFUSION CAN OCCUR, THE ___________________ THE RATE GREATER OF DIFFUSION • CELLS ARE LIMITED IN SIZE BECAUSE THE CELL MEMBRANE MUST TRANSPORT THE FOOD AND OXYGEN TO THE PARTS INSIDE. AS A CELL GETS BIGGER, THE OUTSIDE IS UNABLE TO KEEP UP WITH THE INSIDE, BECAUSE THE INSIDE GROWS AT A FASTER RATE THAN THE OUTSIDE. • REPRESENTED BY THE SURFACE TO VOLUME RATIO, OR S: V. • IN A CELL THAT IS ONE UNIT IN SIZE, THE SURFACE AREA IS 6 SQUARE UNITS AND THE VOLUME IS 1 CUBIC UNIT. THE RATIO THEN IS 6:1. AS A CELL GETS LARGER, THIS RATIO GETS SMALLER, MEANING THE CELL MEMBRANE CANNOT SUPPLY THE INSIDE WITH WHAT IT NEEDS TO SURVIVE. HOW DO LIVING CELLS ACQUIRE ENERGY? • WE’VE SEEN IN THE PREVIOUS LEARNING EXPERIENCE THAT THE CELL USES ENERGY DURING ACTIVE TRANSPORT. WHERE DOES THIS ENERGY COME FROM? SUN • THE ULTIMATE SOURCE OF ALL ENERGY ON EARTH IS THE __________. PHOTOSYNTHESIS CARBON DIOXIDE • PLANTS USE THE SUN’S ENERGY TO CONVERT ________________________ WATER AND ______________ INTO FOOD, IN THE FORM OF OXYGEN CARBOHYDRATES ______________________, AND _________________ CHLOROPHYLL • IT IS THE PIGMENT _________________________ THAT ALLOWS PLANTS TO CONVERT RADIANT ENERGY FROM THE SUN INTO CHEMICAL ENERGY IN THE MOLECULES THAT THEY PRODUCE. CELLULAR RESPIRATION • ANIMALS CANNOT MAKE THEIR OWN FOOD; THEY MUST CONSUME PLANTS OR OTHER ANIMALS. • WHEN ANIMALS EAT FOOD, THEY BREAK DOWN THOSE FOOD MOLECULES BY BREAKING THE BONDS WITHIN THEM. WHEN THESE BONDS ARE BROKEN, ENERGY ________________ IS RELEASED. ENERGY STORAGE • BEFORE ENERGY CAN BE USED IN LIVING SYSTEMS, IT IS FIRST TRANSFORMED INTO A FORM WHICH THE ORGANISM CAN STORE. THIS SPECIAL CARRIER OF ENERGY IS THE MOLECULE ADENOSINE TRIPHOSPHATE (ATP) _______________________________________________. GLUCOSE • _____________________ AND OTHER MOLECULES ARE BROKEN DOWN, MAINLY IN THE MITOCHONDRIA _____________________________ OF CELLS, PRODUCING ATP ENERGY STORAGE PHOSPHATE • WHEN ENERGY IS NEEDED, ATP WORKS BY LOSING THE ENDMOST ___________________ GROUP WHEN INSTRUCTED TO DO SO BY AN ENZYME. ENERGY • THE BROKEN BOND RELEASES ___________________. THE REACTION PRODUCT IS ADENOSINE ADP DIPHOSPHATE (_____________). ENERGY STORAGE • WHEN THE ORGANISM IS RESTING AND ENERGY IS NOT IMMEDIATELY NEEDED, THE REVERSE REATTACHED TO THE REACTION TAKES PLACE AND THE PHOSPHATE GROUP IS _____________________ MOLECULE USING ENERGY OBTAINED FROM FOOD. RECHARGEABLE BATTERY MOLECULE, • THUS THE ATP MOLECULE ACTS AS A "_________________________________" STORING ENERGY WHEN IT IS NOT NEEDED, BUT ABLE TO RELEASE IT INSTANTLY WHEN THE ORGANISM REQUIRES IT.
