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B3A - Molecules of Life

ANIMAL CELLS

(http://a.files.bbci.co.uk/bam/live/content/zstrwmn/small) 

  • NUCLEUS - CONTAINS DNA IN THE FORM OF CHROMOSOMES
  • CELL MEMBRANE - HOLDS CELL TOGETHER AND CONTROLS WHAT GOES IN AND OUT
  • RIBOSOME - WHERE PROTEINS ARE SYNTHESISED
  • CYTOPLASM - GELL LIKE SUBSTANCE WHERE MOST OF CELLS CHEMICAL REACTIONS HAPPEN
  • MITOCHONDRIA - MOST REACTIONS INVOLVED IN RESPIRATION TAKE PLACE (PROVIDES ENERGY FOR CELL PROCESSES) E.G. LIVER CELLS CARRY OUT ENERGY DEMANDING METABOLIC REACTIONS, MUSCLE CELLS NEED ENERGY TO CONTRACT
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B3A - Molecules of Life

PLANT CELLS

(http://www.bbc.co.uk/staticarchive/62c15b1c5544423cf2a9af13f5a913e4c237c3e1.jpg)  

CHLOROPLASTS - WHERE PHOTOSYTHESIS HAPPENS

CELL WALL - MADE OF CELLULOSE - SUPPORTS CELL

VACUOLE - RELATIVELY LARGE STRUCTURE - CONTAINS CELL SAP (WEAK SOLUTION OF SUGGAR AND SALTS

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B3A - Molecules of Life

BACTERIA CELLS

(http://www.bbc.co.uk/staticarchive/0b398673bbf5ca2a2788756bc9d8c76da87b8678.jpg) 

NO CHLOROPLASTS OR MITOCHONDRIA

NO TRUE NUCLEUS - SINGLE CIRCULAR STRAND OF DNA - FLOATS FREELY IN CYTOPLASM

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B3A - Molecules of Life

CHROMOSOMES - LONG MOLECULES OF COILED UP DNA

  • (http://sciencelearn.org.nz/var/sciencelearn/storage/images/contexts/uniquely-me/sci-media/images/cell-chromosomes-and-dna/464336-1-eng-NZ/Cell-chromosomes-and-DNA.jpg)GENES - SHORT SECTIONS OF DIVIDED DNA
  • DNA - DOUBLE HELIX - TWO STRANDS MADE UP OF LOTS OF SMALL GROUPS CALLED NUCLEOTIDES
  • NUCLEOTIDE - CONTAINS SMALL MOLECULE CALLED A BASE - DNA HAS FOUR DIFFERENT BASES - A, C, G, T
  • COMPLEMENTARY BASE PAIRINGS - A AND T, C AND G - EACH BASE CROSS LINKS AND BINDS TO A BASE ON OTHER STRAND TO KEEP CHROMOSOME TIGHTLY TOGETHER - A AND T ALWAYS BIND - C AND G ALWAYS BIND

WATSON AND CRICK

  • FIRST SCIENTISTS TO COME UP WITH STRUCTURE OF DNA - 1959
  • USED DATA FROM OTHER SCIENTISTS TO HELP THEM UNDERSTAND STRUCTURE - X RAY DATA SHOWING DOUBLE HELIX WITH TWO STRANDS WOUND TOGETHER AND DATA SHOWING THAT BASES OCCURED IN PAIRS
  • PUT INFORMATION TOGETHER - BUILT MODEL OF DNA - NOT WIDELY ACCEPTED STRAIGHT AWAY - OTHER SCIENTISTS NEED TO REPEAT WORK TO MAKE SURE RESULTS ARE RELIABLE
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B3A - Molecules of Life

PROTIENS

  • DNA CONTROLS PRODUCTION OF PROTIENS (PROTIEN SYNTHESIS) IN A CELL
  • GENE - SECTION OF DNA THAT CODES FOR A PARTICULAR PROTEIN
  • MADE UP OF CHAINS OF MOLECULES CALLED AMINO ACIDS - EACH DIFFERENT PROTEIN HAS ITS OWN PARTICULAR NUMBER AND ORDER OF AMINO ACIDS
  • GIVES EACH PROTEIN A DIFFERENT SHAPE - EACH A DIFFERENT FUNCTION
  • ORDER OF BASES IN GENE DECIDES ORDER OF AMINO ACIDS IN PROTEIN
  • EACH AMINO ACID CODED FOR BY SEQUENCE OF THREE BASES IN A GENE
  • AMINO ACID ARE JOINED TOGETHER TO MAKE A PROTEIN, FOLLOWING ORDER OF BASES IN GENE
  • EACH GENE CONTAINS DIFFERENT SEQUENCE OF BASES - ALLOWS IT TO CODE FOR UNIQUE PROTEIN

(http://www.bbc.co.uk/schools/gcsebitesize/science/images/add_edex_bio_amino.jpg)

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B3A - Molecules of Life

mRNA - CARRIES CODE TO RIBOSOMES

  • PROTEINS MADE IN CELL CYTOPLASM BY TINY STRUCTURES CALLED RIBOSOMES
  • RIBOSOMES USE CODE IN DNA TO MAKE PROTEINS
  • DNA FOUND IN CELL NUCLEUS - CAN'T MOVE OUT OF IT - CELL NEEDS TO GET CODE FROM DNA TO RIBOSOMES
  • DONE USING mRNA - MADE BY COPYING CODE FROM DNA
  • mRNA - ACTS AS MESSENGER BETWEEN DNA AND RIBOSOME - CARRIES CODE BETWEEN THEM

CONTROL OF CELL 

  • PROTEINS IN CELL AFFECT HOW IT FUNCTIONS - SOME DETERMINE CELL STRUCTURE - OTHERS E.G. ENZYMES CONTROL CELL REACTIONS
  • ONLY MAKE CERTAIN PROTEINS - ONLY SOME OF THE FULL SET OF GENES IS USED IN ANY ONE CELL - REST ARE 'SWITCHED OFF' - PROTEINS THEY CODE FOR AREN'T PRODUCED IN THAT CELL
  • GENES THAT ARE SWITCHED ON DETERMINE FUNCTION OF CELL
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B3B - Proteins and Mutations

PROTEINS - FOUR EXAMPLES

  • ENZYMES
  • CARRIER MOLECULES  - USED TO TRANSPORT SMALLER MOLECULES - HEAMOGLOBIN - BINDS TO OXYGEN MOLECULES AND TRANSPORTS THEM AROUND BODY
  • HORMONES - CARRY MESSAGES AROUND BODY - INSULIN - HOURMONE RELEASED INTO BLOOD BY PANCREAS TO REGULATE BLOOD SUGAR LEVEL
  • STRUCTURAL PROTEINS - PHYSICALLY STRONG - COLLAGEN - STRUCTURED PROTEIN THAT STRENGTHENS CONNECTIVE TISSUES

ENZYMES - BIOLOGICAL CATALYSTS

  • CELLS HAVE THOUSANDS OF REACTIONS E.G. RESPIRATION, PROTEIN SYNTHESIS GOING ON INSIDE THEM - NEEDS TO BE CAREFULLY CONTROLLED - GET RIGHT AMOUNTS OF SUBSTANCES TO KEEP EACH ORGANISM WORKING PROPERLY
  • RAISING TEMP SPEEDS REACTIONS - CELLS START GETTING DAMAGED AT CERTAIN TEMP
  • ENZYMES WORK TO SPEED UP CELL REACTIONS - BIOLOGICAL CATALYSTS - REDUCE NEED FOR HIGH TEMP
  • EVERY BIOLOGICAL REACTION HAS OWN ENZYME, EACH CODED BY SPECIFIC GENE - UNIQUE SHAPE
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B3B - Proteins and Mutations

SPECIFICITY OF ENZYMES

  • (http://media-cache-ec0.pinimg.com/736x/97/bf/a7/97bfa70da58678265a74efdc0c594236.jpg)SUBSTRATE - MOLECULE CHANGED IN CELL REACTION
  • ACTIVE SIGHT - PART THAT JOINS ONTO SUBSTRATE TO CATALYSE REACTION
  • ENZYMES HAVE A HIGH SPECIFICITY FOR THEIR SUBSTRATE - ACTIVE SIGHT OF AN ENZYME ONLY FITS TO ONE PARTICULAR SUBSTRATE
  • FOR ENZYME TO WORK, SUBSTRATE HAS TO FIT ACTIVE SIGHT - REACTION WON'T BE CATALYSED IF SUBSTRATE SHAPE DOESN'T MATCH ACTIVE SIGHT SHAPE - 'LOCK AND KEY' MECHANISM

ENZYMES - pH

  • TOO HIGH OR TOO LOW - INTERFERES WITH BONDS HOLDING ENZYME TOGETHER - CHANGES SHAPE OF ACTIVE SITE - DENATURES ENZYME
  • ENZYMES HAVE OPTIMUM pH THEY WORK BEST AT - OFTEN NEUTREL (pH 7)
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B3B - Proteins and Mutations

CONDITIONS - TEMPERATURE

  • (http://upload.wikimedia.org/wikipedia/commons/6/66/Enzyme-temperature.png)HIGHER TEMPERATURE = FASTER REACTION UP TO CERTAIN POINT
  • MORE HEAT MEANS MORE KINETIC ENERGY - PARTICLES MOVE MORE - MORE COLLISIONS
  • WHEN TEMPERATURE REACHES CERTAIN POINT, ENZYME IS DENATURED - LOSES SHAPE AND DOESN'T FIT SUBSTRATE ANYMORE - REACTION CAN'T BE CATALYSED
  • EACH ENZYME HAS OWN OPTIMUM TEMP - MOST HUMAN ENZYMES IT'S ABOUT 37 DEGREES CELSIUS

Q10 = RATE AT HIGHER TEMPERATURE / RATE AT LOWER TEMPERATURE

  • Q10 VALUE FOR REACTION - SHOWS HOW MUCH RATE CHANGES WHEN TEMP IS RAISED BY 10 DEGREES
  • Q10 VALUE OF 2 MEANS THAT RATE DOUBLES WHEN THE TEMPERATURE IS RAISED BY 10 DEGREES
  • Q10 VALUE OF 3 MEANS RATE TREBLES
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B3B - Proteins and Mutations

GENE MUTATIONS - CHANGE IN DNA BASE SEQUENCE 

  • IF MUTATION OCCURS WITHIN GENE, COULD STOP PRODUCTION OF THE PROTEIN THE GENE NORMALLY CODES FOR - MAY MEAN A DIFFERENT PROTEIN IS PRODUCED INSTEAD

HARMFUL MUTATIONS

  • PRODUCING WRONG PROTEIN OR NO PROTEIN - DISASTER IF IMPORTANT ENZYME
  • MUTATION OCCURS IN REPRODUCTIVE CELLS - OFFSPRING MAY DEVELOP ABNORMALLY OR DIE IN EARLY STAGE OF DEVELOPMENT
  • MUTATION IN BODY CELLS - MUTANT CELLS START TO MULTIPLY IN UNCONTROLLED WAY - CANCER

BENEFICIAL OR HARMLESS MUTATIONS

  • PROTEIN PRODUCED AFTER MUTATION COULD BE IMPROVEMENT TO PROTEIN IT'S SUPPOSED TO BE
  • GIVES ORGANISM SURVIVAL ADVANTAGE - PASSES ON QUALITY TO OFFSPRING - BECOMES COMMON
  • THIS IS NATURAL SELECTION - EVOLUTION E.G. RESISTANT STRAIN BACTERIA
  • SOME MUTATIONS DON'T CHANGE PROTEIN BEING CODED FOR - NO EFFECT ON ORGANISM
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B3B - Proteins and Mutations

CAUSES OF MUTATIONS

  • IONISING RADIATION - E.G. X-RAYS, ULTRAVIOLET LIGHT, RADIATION FROM RADIOACTIVE SUBSTANCES - GREATER DOSE OF RADIATION - GREATER CHANCE OF MUTATION
  • MUTAGENS - CERTAIN CHEMICALS KNOWN TO CAUSE MUTATIONS - IF MUTATIONS PRODUCE CANCER, CHEMICALS ARE OFTEN CALLED CARCINOGENS - CIGARETTE SMOKE CONTIANS CHEMICAL MUTAGENS

 

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B3C - Respiration

RESPIRATION 

  • GOES ON IN EVERY CELL IN BODY - PROCESS OF RELEASING ENERGY FROM GLUCOSE
  • ENERGY FROM RESPIRATION CAN'T BE USED DIRECTLY BY CELLS - USED TO MAKE SUBSTANCE CALLED ATP
  • ATP ACTS AS ENERGY SOURCE FOR MANY CELL PROCESSES AND TRANSPORTS ENERGY TO WHERE IT'S NEEDED IN CELL
  • RESPIRATION CONTROLLED BY ENZYMES - EFFECTED BY TEMP AND pH

AEROBIC RESPIRATION 

  • GLUCOSE + OXYGEN ---> CARBON DIOXIDE + WATER (+ ENERGY)
  • C6H12O6  +      O2      --->           CO2              +    H2O   (+ ENERGY)
  • HAPPENS WHEN THERES PLENTY OF OXYGEN AVAILABLE - MOST EFFICIENT RELEASE OF ENERGY FROM GLUCOSE
  • TYPE OF RESPIRATION USED MOST OF THE TIME
  • WHEN RESPIRATION INCREASES, OXYGEN CONSUMPTION AND CARBON DIOXIDE PRODUCTION INCREASE
  • RATE OF OXYGEN CONSUMPTION USED TO ESTIMATE METABOLIC RATE (AMOUNT OF ENERGY BEING USED)
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B3C - Respiration

ANAEROBIC RESPIRATION

  • GLUCOSE ---> LACTIC ACID (+ENERGY)
  • WHEN ONE DOES VIGOROUS EXERCISE, THEIR BODY CAN'T SUPPLY ENOUGH OXYGEN TO THEIR MUSCLES EVEN THOUGH HEARTRATE AND BREATHING RATE INCREASE AS MUCH AS THEY CAN
  • MUSCLES HAVE TO START RESPIRING ANAEROBICALLY ASWELL
  • NOT THE BEST WAY TO CONVERT GLUCOSE TO ENERGY - RELEASES MUCH LESS ENERGY PER GLUCOSE MOLECULE THAN AEROBIC RESPIRATION
  • GLUCOSE ONLY PARTIALLY BROKEN DOWN - LACTIC ACID PRODUCED
  • LACTIC ACID BUILDS UP IN MUSCLES - LEADS TO PAIN AND MUSCLE FATIGUE
  • ADVANTAGE - ALLOWS YOU TO KEEP USING MUSCLES WHEN OXYGEN IS USED UP
  • AFTER RESORTING TO ANAEROBIC RESPIRATION, WHEN YOU STOP EXERCISING YOU'LL HAVE AN OXYGEN DEBT - NEED EXTRA OXYGEN TO BREAK DOWN LACTIC ACID BUILT UP IN MUSCLES TO ALLOW AEROBIC RESPERATION TO BEGIN AGAIN - NEED TO KEEP BREATHING HARD AFTER EXERCISE - REPAY DEBT
  • LACTIC ACID - CARRIED TO LIVER TO BE BROKEN DOWN - HEART RATE HAS TO STAY HIGH FOR THIS

RESPIRATORY QUOTENT = AMOUNT OF CO2 PRODUCED / AMOUNT OF O2 USED - TELLS WHETHER SOMEONE IS RESPIRING ANAEROBICALLY (>1) OR AEROBICALLY (0.7 - 1)

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B3D - Cell Division

MULTICELLULAR AND SINGLE CELLED ORGANISMS

  • HUMANS ARE MULTICELLULAR - ADVANTAGES - 
  • CAN BE BIGGER - CAN TRAVEL FURTHER, GET NUTRIENTS IN A VERIETY OF DIFFERENT WAYS, NOT GET SQUASHED OR STEPPED ON ETC.
  • ALLOWS FOR CELL DIFFERENTIATION - CAN HAVE DIFFERENT TYPES OF CELLS THAT DO DIFFERENT JOBS - CELLS CAN BE SPECIALLY ADAPTED TO THEIR PARTICULAR JOB
  • THIS MEANS THEY CAN BE MORE COMPLEX - SPECIALISED ORGANS, DIFFERENT SHAPES AND BEHAVIOUR - CAN BE ADAPTED SPECIFICALLY TO THEIR PARTICULAR ENVIRONMENT
  • DISADVANTAGES - HAVE TO HAVE SPECIALIST ORGAN SYSTEMS E.G.
  • - SYSTEM TO COMMUNICATE BETWEEN DIFFERENT CELLS - NERVOUS SYSTEM
  • - SYSTEM TO SUPPLY CELLS WITH NUTRIENTS THEY NEED - CIRCULATORY SYSTEM
  • - SYSTEM THAT CONTROLS EXCHANGE OF SUBSTANCES WITH ENVIRONMENT - RESPIRATORY SYSTEM
  • SINGLE CELLED ORGANISMS INCLUDE BACTERIA
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B3D - Cell Division

DNA REPLICATTION

  • (http://phsgirard.org/Biology/Genetics/DNA/DNAreplication.gif)DNA HAS TO REPLICATE ITSELF PRIOR TO CELL DIVISION SO EACH NEW CELL HAS FULL AMOUNT OF DNA
  • DNA DOUBLE HELIX 'UNZIPS' - FORMS TWO SINGLE STRANDS
  • NEW NUCLEOTIDES (FLOATING FREELY IN NUCLEUS) JOIN ON USING COMPLIMENTARY BASE PAIRINGS - MAKES EXACT COPY OF DNA ON OTHER STRAND
  • RESULT - TWO DOUBLE STRANDED MOLECULES OF DNA IDENTICAL TO ORIGIONAL MOLECULE OF DNA

MITOSIS - WHEN A CELL REPRODUCES ITSELF BY SPLITTING TO FORM TWO IDENTICAL OFFSPRING

  • HAPPENS WHEN YOU WANT IDENTICAL CELLS E.G. GROWTH
  • BEFORE IT STARTS, DNA IS REPLICATED
  • DNA COILS UP INTO DOUBLE ARMED CHROMOSOMES - BOTH ARMS CONTAIN EXACT SAME INFORMATION
  • CHROMOSOMES LINE UP IN CENTRE OF CELL - DIVIDE AS CELL FIBRES PULL THEM APART - TWO ARMS OF EACH CHROMOSOME GO TO OPPISITE POLES (ENDS) OF CELL 
  • MEMBRANES FORM AROUND NEW SETS OF CHROMOSOMES
  • CYTOPLASM DIVIDES - TWO NEW CELLS WITH THE EXACT SAME GENETIC MATERIAL
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B3D - Cell Division

MEIOSIS - TYPE OF CELL DIVISION WHICH CREATES GAMETES

  • GAMETES - SEX CELLS - EGGS AND SPERM - FORMED BY MEIOSIS IN THE OVARIES AND TESTES 
  • DIPLOID - BODY CELLS - EACH OF THE ORGANISMS BODY CELLS HAVE TWO COPIES OF EACH CHROMOSOME IN IT'S NUCLEUS - ONE FROM MUM, ONE FROM DAD
  • HAPLOID - GAMETES - ONLY HAVE ONE COPY OF EACH CHROMOSOME - EGG AND SPERM COMBINE TO FORM DIPLOID NUMBER OF CHROMOSOMES         

PROCESS OF MEIOSIS

  • DNA REPLICATES ITSELF, CURLS UP INTO DOUBLE ARMED CHROMOSOME (LIKE MITOSIS)
  • CHROMOSOMES ARRANGE THEMSELVES INTO PAIRS - HUMANS HAVE 23 PAIRS OF CHROMOSOMES - 46 ALTOGETHER - BOTH CHROMOSOMES IN A PAIR CONTAIN INFORMATION ABOUT SAME FEATURES, ONE FROM MUM AND ONE FROM DAD
  • FIRST DIVISION - PAIRS SPLIT UP - CHROMOSOMES IN EACH PAIR MOVE TO DIFFERENT POLES OF CELL - IN EACH OF THE TWO NEW CELLS THERE ARE NO PAIRS - MIXTURE OF MUM AND DADS CHROMOSOMES - 23
  • SECOND DIVISION - LIKE MITOSIS - CHROMOSOME SPLITS IN HALF - ONE ARM ENDS UP IN EACH NEW CELL
  • FOUR NEW CELLS - TWO AFTER FIRST DIVISION, EACH OF THOSE SPLIT AGAIN - CELLS GENETICALLY DIFFERENT - CHROMOSOMES GET SHUFFLED UP - EACH GAMETE GETS HALF AT RANDOM
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B3D - Cell Division

GENETIC VARIATION

  • FERTILISATION - MALE AND FEMALE GAMETES COMBINE TO FORM DIPLOID CELL - ZYGOTE
  • CHARACTERISTICS OF ZYGOTE CONTROLLED BY COMBINATION OF GENES ON IT'S CHROMOSOMES
  • ZYGOTE INHERITED CHROMOSOMES FROM BOTH PARENTS - SHOW FEATURES OF BOTH PARENTS BUT WON'T BE EXACTLY LIKE EITHER OF THEM

ADAPTATIONS OF SPERM CELL

  • FUNCTION - TRANSPORT MALES DNA TO FEMALE EGG
  • SMALL AND HAVE LONG TAILS - SWIM TO EGG
  • LOTS OF MITOCHONDRIA - PROVIDE ENERGY NEEDED TO SWIM DISTANCE
  • ACROSOME AT FRONT OF HEAD - RELEASE ENZYMES NEEDED TO DIGEST WAY THROUGH MEMBRANE OF EGG CELL 

(http://www.oldschool.com.sg/modpub/7962434324a3a7f5d8e0d5)

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B3E - The Circulatory System

BLOOD PLASMA - PALE YELLOW LIQUID WHICH CARRIES EVERYTHING THAT NEEDS TRANSPORTING AROUND BODY:

  • RED BLOOD CELLS, WHITE BLOOD CELLS (IMMUNITY) AND PLATELETS (USED IN BLOOD CLOTTING)
  • WATER
  • DIGESTED FOOD PRODUCTS LIKE GLUCOSE AND AMINO ACIDS FROM GUT TO BODY CELLS
  • CARBON DIOXIDE - FROM BODY CELLS TO LUNGS
  • UREA FROM LIVER TO KIDNEYS WHERE IT IS REMOVED IN URINE
  • HOURMONES - ACT LIKE CHEMICAL MESSENGERS
  • ANTIBODIES - PROTEINS INVOLVED IN BODY'S IMMUNE RESPONSE

RED BLOOD CELLS - CARRY OXYGEN FROM LUNGS TO ALL CELLS IN BODY

  • SMALL, BICONCAVE SHAPE - LARGE SURFACE AREA TO VOLUME RATIO FOR ABSORBING/RELEASING O2
  • CONTAIN HEAMOGLOBIN - GIVES BLOOD COLOUR - CONTAINS IRON - COMBINES WITH OXYGEN IN LUNGS TO BECOME OXYHEAMOGLOBIN - REVERSE HAPPENS IN BODY CELLS TO RELEASE OXYGEN
  • NO NUCLEUS - MORE SPACE FOR HEAMOGLOBIN - CARRIES MORE OXYGEN
  • VERY FLEXIBLE - EASILY PASS THROUGH TINY CAPILLARIES
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B3E - The Circulatory System

ARTERIES - CARRY BLOOD AWAY FROM HEART

  • HEART PUMPS BLOOD OUT AT HIGH PRESSURE - ARTERY WALLS STRONG AND ELASTIC TO COPE WITH IT
  • WALLS ARE THICK COMPARED TO SIZE OF LUMEN 
  • WALLS CONTAIN THICK LAYERS OF MUSCLE TO MAKE THEM STRONG

CAPILLARIES - INVOLVED IN EXCHANGE OF MATERIALS AT TISSUES

  • ARTERIES BRANCH ONTO CAPILLARIES - REALLY TINY - TOO SMALL TO SEE
  • USES - CARRY BLOOD REALLY CLOSE TO EVERY CELL TO EXCHANGE SUBSTANCES WITH THEM
  • SUPPLY FOOD AND OXYGEN AND TAKE AWAY WASTES LIKE CO2 
  • ADAPTIONS - PERMEABLE WALLS - SUBSTANCES CAN DIFFUSE IN AND OUT
  • WALLS ONE CELL THICK - ICREASES RATE OF DIFFUSION BY DECREASING DISTANCE OVER WHICH IT OCCURS

VEINS - CARRY BLOOD TO THE HEART

  • CAPILLARIES JOIN UP EVENTUALLY TO FORM VEINS
  • BLOOD AT LOWER PRESSURE IN VEINS - WALLS NOT AS THICK - BIGGER LUMEN THAN ARTERIES - HELP BLOOD FLOW DESPITE LOWER PRESSURE - VALVES - KEEP BLOOD FLOWING RIGHT WAY
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B3E - The Circulatory System

DOUBLE CIRCULATORY SYSTEMS

  • FIRST SYSTEM - CONNECTS HEART TO LUNGS - DEOXYGENATED BLOOD PUMPED TO LUNGS TO TAKE IN OXYGEN - BLOOD RETURNS TO HEART
  • SECOND SYSTEM - CONNECTS HEART TO REST OF BODY - OXYGENATED BLOOD PUMPED OUT TO BODY - GIVES UP OXYGEN - DEOXYGENATED BLOOD RETURNED TO HEART TO BE PUMPED TO LUNGS AGAIN
  • ADVANTAGES - RETURNING BLOOD TO HEART AFTER BEING OXYGENATED MEANS IT CAN BE PUMPED TO REST OF BODY AT MUCH HIGHER PRESSURE - INCREASES RATE OF BLOOD FLOW TO TISSUES - MORE OXYGEN DELIVERED TO CELLS - IMPORTANT FOR MAMMALS - USE UP A LOT OF OXYGEN MAINTAINING BODY TEMP
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B3E - The Circulatory System

THE HEART

  • (http://1.bp.blogspot.com/-iyTdGwuePEk/Ty_--4TPRFI/AAAAAAAAAd0/c0_3POaWQOw/s1600/heart.jpg)RIGHT ATRIUM RECEIVES DEOXYGENATED BLOOD FROM BODY THROUGH VENA CAVA
  • DEOXYGENATED BLOOD MOVES THROUGH RIGHT VENTRICLE WHICH PUMPS IT TO LUNGS THROUGH PULMONARY ARTERY
  • LEFT ATRIUM RECEIVES OXYGENATED BLOOD FROM LUNGS THROUGH PULMONARY VEIN
  • OXYGENATED BLOOD MOVES THORUGH TO LEFT VENTRICLE WHICH PUMPS IT AROUND WHOLE BODY VIA AORTA
  • LEFT VENTRICLE - MUCH THICKER WALL THAN RIGHT VENTRICLE - NEEDS MORE MUSCLE - HAS TO PUMP BLOOD AROUND WHOLE BODY, NOT JUST TO LUNGS
  • SEMILUNAR, BICUSPID AND TRICUSPID VALVES PREVENT BACKFLOW OF BLOOD
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B3F - Growth and Development

ANIMAL AND PLANT GROWTH

  • PLANTS - GROW CONTINUOUSLY - GROWTH IN HEIGHT MAINLY TO DO WITH CELL ELONGATION - CELL DIVISION HAPPENS IN TIPS OF ROOTS AND SHOOTS
  • ANIMALS - GROW UNTIL THEY RRERACH A FINITE SIZE THEN STOP GROWING - GROWTH HAPPENS BY CELL DIVISION IN TIPS OF ROOTS AND SHOOTS

STEM CELLS

  • DIFFERENCIATION - THE PROCESS IN WHICH CELL CHANGES TO BECOME SPECIALISED FOR ITS JOB
  • ABILITY TO DIFFERENTIATE LOST AT EARLY STAGE IN HUMANS - PLANTS NEVER LOSE IT
  • MOST CELLS IN BODY SPECIALISED FOR A PARTICULAR JOB
  • STEM CELLS - UNDIFFERENTIATED CELLS - CAN DEVELOP INTO DIFFERENT TYPES OF CELLS TISSUES AND ORGANS DEPENDING ON INSTRCTIONS GIVEN
  • FOUND IN EMBYOS - HAVE ABILITY TO TURN INTO ANY CELL, TISSUE OR ORGAN
  • ADULTS HAVE STEM CELLS - ONLY FOUND IN BONE MARROW - AREN'T AS VERSITILE AS EMBRTO STEM CELLS - CAN ONLY TURN INTO CERTAIN CELLS
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B3F - Growth and Development

STEM CELL RESEARCH - BENEFITS

  • BLOOD CANCER - CURED WITH BONE MARROW TRANSPLANTS - CONTAINS CERTAIN ADULT STEM CELLS - TURN INTO NEW BLOOD CELLS TO REPLACE OLD ONES
  • EARLY HUMAN EMBRYOS - CONTAINS LOTS OF STEM CELLS - SCIENTISTS CAN EXTRACT THESE CELLS AND GROW THEM - WILL EVENTUALLY BE ABLE TO GROW TISSUES TO TREAT MEDICAL CONDITIONS

STEM CELL RESEARCH - ARGUMENTS FOR AND AGAINST

  • FEEL THAT HUMAN EMBRYOS SHOULDN'T BE USED FOR EXPERIMENTS - EACH ONE POTENTIAL LIFE
  • OTHERS THINK PATIENTS WHO ALREADY EXIST AND SUFFERING ARE MORE IMPORTANT THAN EMBRYOS
  • EMBRYOS USED IN RESEARCH - ONES WHUCH HAVE BEEN DISCARDED IN FERTILITY CLINICS - WOULD HAVE BEEN THROWN AWAY ANYWAY
  • CAMPAIGNERS FOR EMBRYO RIGHTS PROTEST THIS TOO
  • NOW 'STOCKS' OF STEM CELLS - SCIENTISTS CAN USE THEM FOR RESEARCH
  • SOME COUNTRIES E.G. USA WON'T FUND RESEARCH TO MAKE NEW STEM CELL STOCKS - UK ALLOWS IT UNDER STRICT GUIDELINES
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B3F - Growth and Development

METHODS OF MEASURING GROWTH

  • LENGTH - MEASURING LENTH OR HEIGHT OF PLANT OR ANIMAL - EASY TO MEASURE - BUT DOESN'T TELL YOU ABOUT CHANGES IN WIDTH, DIAMETER, NUMBER OF BRANCHES ETC.
  • WET MASS - WEIGHING PLANT OR ANIMAL - EASY TO MEASURE - BUT CHANGABLE - PLANT IS HEAVIER WHN IT'S RECENTLY RAINED, ANIMALS HEAVIER WHEN BLADDER FULL ETC.
  • DRY MASS - DRYING OUT ORGANISM BEFORE WEIGHING IT - NOT AFFECTED BY AMOUNT OF WATER ORGANISM HAS HAD - BUT ORGANISMS HAVE TO BE KILLED BEFORE BEING WEIGHED

PHASES OF HUMAN GROWTH

  • INFANCY - ROUGHLY FIRST TWO YEARS OF LIFE - RAPID GROWTH
  • CHILDHOOD - PERIOD BETWEEN INFANCY AND PUBERTY - STEADY GROWTH
  • ADOLESCENCE - BEGINS WITH PUBERTY - CONTINUES UNTIL BODY GROWTH AND DEVELOPMENT COMPLETE - RAPID GROWTH
  • MATURITY/ADULTHOOD - PERIOD BETWEEN ADOLESCENCE AND OLD AGE - GROWTH STOPS
  • OLD AGE - USUALLY CONSIDERED BETWEEN AGE OF 65 AND DEATH
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B3F - Growth and Development

MAIN PHASES OF RAPID GROWTH

  • JUST AFTER BIRTH AND DURING ADOLESCENCE
  • TYPICAL HUMAN GROWTH CURVE - STRETCHED S SHAPE - STEEPER CURVE - MORE RAPID GROWTH

GROWTH RATES OF DIFFERENT BODY PARTS

  • BODY DOESN'T GROW EVENLY
  • DIFFERENT PARTS OF BODY GROWS AT DIFFERENT RATES AT DIFFERENT TIMES
  • E.G. IN EMBRYOS, BRAIN GROWS FASTEST - GIVES HUMANS BEST SURVIVAL ADVANTAGE - BEST TOOL HUMANS HAVE FOR FINDING FOOD, AVOIDING PREDETORS ETC.
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B3G - New Genes for Old

SELECTIVE BREEDING - HUMANS ARTIFICIALLY SELECT PLANTS OR ANIMALS TO BREED TO HAVE THEIR GENES STAY IN THE POPULATION ACCORDING TO WHAT WE WANT FROM THEM

  • ORGANISMS ARTIFICIALLY SELECTED TO DEVELOP FEATURES SUCH AS:
    • MAXIMUM YEILD OF MEAT, MILK, GRAIN ETC.
    • GOOD HEALTH AND DISEASE RESISTANCE
    • SPEED, ATTRACTIVENESS ETC.
  • PRCESS OF SELECTIVE BREEDING INVOLVES:EXAMPLE - AGRICULTURE - IMPROVE YEILD - E.G. FARMERS BREED ANIMALS WITH BEST CHARACTERISTICS FOR PRODUCING MEAT TOGETHER FOR HIGHER MEAT YEILD
    • SELECT ONES FROM EXISTING STOCK WHICH HAVE BEST CHARACTERISTICS
    • BREED THEM WITH EACHOTHER
    • SELECT BEST OFFSPRING - BREED THEM TOGETHER
    • CONTINUE PROCESS OVER SEVERAL GENERATIONS
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B3G - New Genes for Old

REDUCTION IN GENE POOL

  • GENE POOL - NUMBER OF DIFFERENT ALELLES PRESENT IN POPULATION
  • INBREEDING - FARMER BREEDS BEST ANIMALS - CLOSELY RELATED 
  • HEALTH PROBLEMS - MORE CHANCE OF ORGANISM DEVELOPING GENETIC DISORDERS - LOTS OF GENETIC CONDITIONS RECESSIVE - NEED TWO ALLELES TO BE SAME TO HAVE AN EFFECT - RECESSIVE ALLELES MORE LIKELY TO BUILD UP IN POPULATION IF CLOSELY RELATED ANIMALS ARE BREEDED TOGETHER
  • NEW DISEASE APPEARS - SERIOUS PROBLEM - NOT MUCH VARIATION IN POPULATION - STOCK CLOSELY RELATED - ONE OF THEM IS KILLED THEN OTHERS LIKELY TO BE KILLED
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B3G - New Genes for Old

GENETIC ENGINEERING - MOVING GENES FROM ONE ORGANISM TO ANOTHER SO THAT IT PRODUCES USEFUL BIOLOGICAL PRODUCTS

  • GENE RESPONSIBLE FOR PRODUCING DESIRABLE CHARACTERISTIC SELECTED 
  • CUT FROM DNA USING ENZYMES AND ISOLATED
  • USEFUL GENE INSERTED INTO DNA OF ANOTHER ORGANISM
  • ORGANISM REPLICATES - LOADS OF SIMILAR ORGANISMS PRODUCTING USEFUL PRODUCT

EXAMPLES OF GENETIC ENGINEERING

  • VITAMIN A - TAKE GENES FROM CARROTS THAT CONTROL BETA CAROTINE PRODUCTION - PUT THEM IN RICE - RICE EATEN THROUGHOUT WORLD - HUMANS CHANGE BETA CAROTINE INTO VITAMIN A
  • INSULIN - GENE FOR HUMAN INSULIN PRODUCTION PUT INTO BACTERIA - CULTURED IN FERMENTER - HUMAN INSULIN EXTRACTED FROM MEDIUM AS THEY PRODUCE IT
  • RESISTANCE TO HERBICIDES, FROST DAMAGE AND DISEASE - CUT OUT OF PLANTS THAT WE DON'T WANT TO GROW AND PUT INTO USEFUL ONES
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B3G - New Genes for Old

ADVANTAGES AND RISKS OF GENETIC ENGINEERING

  • ADVANTAGE - CAN PRODUCE ORGANISMS WITH NEW AND USEFUL FEATURES VERY QUICKLY
  • RISK - INSERTED GENE MAY HAVE UNEXPECTED, HARMFUL EFFECTS - E.G. GENETICALLY ENGINEERED BACTERIA MAY MUTATE AND BECOME PATHOGENETIC - FOREIGN GENES MAY MAKE THEM MORE HARMFUL AND UNPREDICTABLE
  • RISK - GENES MAY ESCAPE - E.G. WEEDS GAIN PESTICIDE RESISTANT GENES FROM USEFUL PLANT

ETHICAL ISSUES

  • WRONG TO GENETICALLY ENGINEER ORGANISMS PURELY FOR HUMAN BENEFIT - PARTICULAR PROBLEM WITH GENETIC ENGINEERING OF ANIMALS, PARTICULARLY IF ANIMAL HARMED
  • WON'T STOP AT PLANTS AND ANIMALS - RICH MAY BE ABLE TO PAY FOR BABY TO BE GENETICALLY ENGINEERED TO HAVE GOOD CHARACTERISTICS - THOSE WHO CAN'T AFFORD IT WILL BE 'GENETIC UNDERCLASS'
  • EVOLUTIONARY CONSEQUENCES UNKNOWN - IRRESPONSIBLE IF WE DON'T KNOW THE IMPACT ON FUTURE GENERATIONS
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B3G - New Genes for Old

GENE THERAPY - ALTERING A PERSONS GENES TO CURE GENETIC DISORDERS - TWO TYPES:

  • CHANGING BODY CELLS - PARTICULARLY CELLS MOST AFFECTED BY DISORDER - E.G. CYSTIC FIBROSIS - LUNGS WOULD BE TARGETED - WOULDN'T AFFECT GAMETES - DISEASE COULD STILL BE INHERITED
  • CHANGING GENES IN GAMETES - EVERY CELL IN BODY OF OFFSPRING AFFECTED - WON'T INHERIT DISEASE - CURRENTLY ILLEGAL

ETHICAL ISSUES OF GAMETE THERAPY

  • UNEXPECTED CONSEQUENCES - CAUSE NEW SET OF PROBLEMS - HARMFUL GENES INHERITED BY OFFSPRING
  • COULD LEAD TO CREATION OF 'DESIGNER BABIES' - PARENTS CHOOSE GENES THEY WANT CHILDREN TO HAVE
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B3H - Cloning

CLONES - GENETICALLY IDENTICAL ORGANISMS

CLONING OF ADULT ANIMAL - DONE BY TRANSFERRING THE NUCLEUS - NUCLEAR TRANSFER - E.G. DOLLY SHEEP

  • NUCLEUS OF SHEEPS EGG CELL REMOVED - LEFT EGG WITHOUT ANY GENETIC INFORMATION
  • ANOTHER NUCLEUS INSERTED IN IT'S PLACE - DIPLOID NUCLEUS FROM UDDER CELL OF SHEEP BEING CLONED - HAD ALL OTHER SHEEPS GENETIC INFORMATION
  • CELL GIVEN ELECTRIC SHOCK - STARTED DIVIDING MY MITOSIS
  • DIVIDING CELL )NOW AN EMBREO) PLANTED INTO UTERUS OF SURROGATE MOTHER SHEEP TO DEVLOP UNTIL READY TO BE BORN
  • RESULT - DOLLY - CLONED SHEEP FROM WHICH THE UDDER CELL CAME

CLONING HUMANS - ETHICAL ISSUES

  • LOTS OF SURROGATE PREGNANCIES - HIGH RATES OF MISCARRIAGE AND STILLBIRTH
  • CLONES OF OTHER ANIMALS HAVE BEEN UNHEALTHY - OFTEN DIE PREMATURELY
  • CLONE MAY BE PSYCOLOGICALLY DAMAGED TO KNOW THAT IT'S JUST A CLONE OF ANOTHER HUMAN
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B3H - Cloning

BENEFITS OF CLONING

  • ALLOWS PRODUCTION OF ANIMALS WITH DESIRABLE CHARACTERISTICSHUMAN EMBREOS PRODUCED BY CLONING ADULT BODY CELLS - EMBREOS USED TO SUPPLY STEM CELLS FOR STEM CELL THERAPY - EXACTLY THE SAME GENETIC INFORMATION AS PATIENT - REDUCED RISK OF REJECTION
    • ANIMALS WHICH PRODUCE MEDICINES IN THEIR MILK DEVELOPED BY GENETIC ENGINEERING AND CLONED - USEFUL HUMAN GENES TRANSFERRED TO SHEEP AND COWS AND PUT INTO HUMANS WITHOUT USEFUL GENE E.G. BLOOD CLOTTING AGENT PUT INTO PEOPLE WITH HAEMOPHILIA
    • ANIMALS WITH ORGANS SUITABLE FOR TRANSPLANTATION CLONED - CONSTANT SUPPLY OF ORGANS FOR TRANSPLANT - SOLVE PROBLEM OF LIMITED SUPPLY (ALTHOUGH THERE ARE ISSUES E.G. VIRUSES PASSED FROM ANIMALS TO HUMANS)

RISKS OF CLONING

  • CLONES NOT AS HEALTHY AS NORMAL ANIMALS
  • NEW SCIENCE - MAY HAVE CONSEQUENCES WE'RE NOT YET AWARE OF
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B3H - Cloning

COMMERCIAL CLONING OF PLANTS - EASIER THAN CLONING ANIMALS

  • PLANT WANTED IS CHOSEN BASED ON CHARACTERISTICS
  • REMOVE SEVERAL SMALL PIECES OF TISSUE FROM PARENT PLANT - BEST RESULTS IF TISSUE TAKEN FROM FAST GROWING SHOOTS OR TIPS
  • GROW TISSUE IN GROWTH MEDIUM CONTAINING NUTRIENTS AND GROWTH HORMONES - DONE UNDER ANTISEPTIC CONDITIONS TO PREVENT MICROBE HARMING PLANT
  • TISSUES PRODUCE SHOOTS AND ROOTS - MOVED TO POTTING COMPOST TO CARRY ON GROWING

COMMERCIAL USE OF CLONED PLANTS - PROS AND CONS

  • PRO - CAN BE FAIRLY SURE OF CHARACTERISTICS OF PLANT - GENETICALLY IDENTICAL TO PARENTS - DON'T WASTE TIME OR MONEY GROWING BAD PLANTS
    • POSSIBLE TO MASS PRODUCE PLANTS THAT ARE HARD TO GROW FROM SEEDS
  • CON - SUFFER FROM DISEASE DUE TO CHANGE IN ENVIRONMENT - ALL PLANTS WILL SUFFER - SAME GENES
    • LACK OF GENETIC VARIATION
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Comments

AineRobinson

Cant print this one off for some reason

liv barker

very good notes however i am unable to print them !

taqinisa

not ocr b3

*Alisha*

Good notes:))

*Alisha*

^^^ I think its because this is OCR Gateway and your probably doing OCR 21st Century

J.Duncan

could you please re upload it so I am able to print them because they are really good notes?

ShangrafAhmed

k

ShangrafAhmed

asia

gurdeep99

good notes unable to print off

SAHMED465

Amazing, but unable to print off =(

Amena shaikh

really good notes

elbally

would like to be able to print them off

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