Igcse Notes Biology Updated[155].docx

IGCSE Biology (9-1) Triple Award Characteristics of living things Movement Respiration Sensitivity Growth Reproduction Excretion Nutrition Cells Eukaryotic cell- Has membrane bound organelles Prokaryotic cell- Has NO membrane bound organelles        

Cell membrane controls entry and exit of substances into a cell. Cytoplasm is where chemical reactions take place. Nucleus controls the activities of the cell. Mitochondrion is where aerobic respiration takes place. Ribosomes play a role in protein synthesis. Vacuoles are filled with cell sap that contains dissolved sugars and mineral salts Chloroplasts carry out photosynthesis and is filled with chlorophyll Cell wall is made of cellulose, protects and supports the cell

CELL TISSUE  TISSUE  ORGAN  ORGAN SYSTEM 

A group of _____ working together to perform the same function.



Organ systems- Digestive system, Endocrine System, Reproductive system, Circulatory system, Respiratory system, Nervous system, Excretory system

Differentiation- process where cells are specialised. Stem cells- Have the ability to divide many times without differenciating.

 

Embryonic can differenciate into any time of cell. Adult cannot differenciate and only produces Red Blood Cells.

Kingdoms – Plants, Protoctists, Animals, Fungi, Bacteria

   

Bacterial cell- Pathogenic/non-pathogenic and Unicellular Viruses – Non-living, Pathogenic and DO NOT-excrete,

respire, grow Protoctists – Unicellular/multicellular Fungi – have thread-like structures called hyphae that form a network called mycelium, carry out saprotrophic nutrition- extracellular secretion of enzymes onto dead matter. (glucose  ethanol + carbon dioxide) -yeast



Too high temperatures cause enzymes to denature and the active site has changed its shape

Effect of pH level on enzyme activity.



Enzymes have different optimum pH levels.

Transport 

 

Diffusion Net movement of particles from an area of a high concentration to an area of low concentration. Osmosis Net movement of water molecules from an area of high water potential to an area of low water potential. Active transport Net movement of particles from an area of low concentration to area of high concentration using energy.

[Amoeba single celled and has high surface area to volume ratio to increase diffusion rate.]

Photosynthesis  

Light is absorbed by chloroplast that contain chlorophyll. Carbon dioxide enters leaf through stomata. Carbon dioxide + water  glucose + oxygen 6 CO2 + 6 H2O  C6H12O6 + 6 O2

Limiting factors   

Temperature Carbon dioxide Light intensity

Role of Diffusion in gas exchange in plants

 

Oxygen and carbon dioxide diffuse into the leaf through stomata During day, excess oxygen diffuses out of the leaf into atmosphere

leaf structure Adaptation large surface area, thin, flat Functions       

Waxy cuticle To prevent transpiration Upper epidermis transparent to allow sunlight to enter leaf. Palisade mesophyll contains a lot of chloroplasts which absorb light for photosynthesis Spongy mesophyll air spaces to allow diffusion of gases Vein contains xylem and phloem Guard cells control opening and closure of stomata Stomataallows carbon dioxide in and oxygen out of leaf

Biological Molecules

Glucose made in photosynthesis used to make proteins, fats, cellulose for cell walls, starch for storage.

Carbohydrates carbon, hydrogen, oxygen

Mineral ions are absorbed by active transport into root hair cell

Proteins carbon, hydrogen, oxygen, nitrogen, [sulfur] Lipids carbon, hydrogen, oxygen [3 fatty acids + glycerol] EnzymesBiological catalysts that speed up the reaction without being used up.   

Amylase digests starch to glucose [salivary glands, small intestine, pancreas] Protease digests proteins to amino acids [salivary glands, small intestine, pancreas] Lipase digests lipids to fatty acids + glycerol [small intestine, pancreas]

Effect of Temperature on enzyme activity 

At low temperatures, enzyme substrates have very little kinetic energy.

 

Magnesium to make chlorophyll [deficiency= yellow leaves] Nitratesto build proteins [deficiency=stunted growth]

Digestive system Breakdown of large insoluble molecules into small soluble ones. Peristalsis  muscular contractions push the bolus of food down the oesophagus Hydrochloric acid breaks down food, kills pathogens

Bile made in LIVER, stored in GALL BLADDER and released in small intestine.



Emulsifier it breaks down large fat droplets into small ones to increase surface area for LIPASE to work more easily.



Neutralises hydrochloric acid

Villi structure 

Cilia have hairs which waft the bacteria ladened mucus out of lungs

Thin surface layer, capillaries, lacteal, blood vessel

Adaptation of small intestine    

Large surface area Lots of capillaries Thin wall, short diffusion distance Lacteals for absorption of fats

Large intestine where water is reabsorbed into blood Rectum  faeces stored there before passing out via anus

    

Goblet cells secrete mucus that traps pathogens

Egestion removal of faeces from anus Excretion removal of waste products of metabolism Ingestiontaking food in your body Metabolism the rate of a which chemical reactions happen Assimilation building up large molecules from small ones

Balanced diet  contains carbohydrates, fats, proteins, vitamins, minerals, fibre, water Carbohydratessource of energy [ bread, rice] Proteins important for growth and repair of muscles [chicken, beef Lack of protein= KWASHIORKOR FatsVery concentrated source of energy and used in insulation. [dairy, butter, cream]

Inhalation      Exhalation

    

C- Helps to stick cells together in your mouth. [citrus, lemon, orange juice] Lack of Vitamin C= SCURVY D-Needed for stronger bones [ fish oils] Lack of Vitamin D= Rickets A-allows to see in dim light [fish oils, margarine, carrots] Lack of Vitamin A= NIGHT BLINDNESS Iron needed to manufacture haemoglobin found in red blood cells. [red meat, spanich] Lack of Iron= ANAEMIA Calciumneeded for stronger teeth and bones [milk] Lack of calcium= RICKETS FibreEssential to help food move through digestive system [fruits and vegetables] Lack of fibre= CONSTIPATION

Respiration Process carried out in the mitochondria which releases energy [ATP]-energy storage ATP used for cell division  to build up large molecules from small ones  Active transport  Muscle contraction Aerobic respiration Oxygen + Glucose Carbon dioxide + Water

INTERNAL intercoastal muscles contract. Ribs move DOWN and IN. Diaphragm RELAXES and becomes DOME SHAPED. Volume in thorax DECREASES and pressure INCREASES. Air is forced OUT of lungs.

Alveoli adaptations    

Large surface area Good blood supply Thin walls} Short diffusion pathway Moist} Dissolve gases

Effects of SMOKING on LUNGS    

VitaminsC, D, A

EXTERNAL intercoastal muscles contract. Ribs move UP and OUT. Diaphragm CONTRACTS and FLATTENS. Volume in thorax INCREASES and pressure DECREASES. Air is sucked INTO lungs.

Cilia are paralysed build up of mucus smokers cough infection bronchitis Alveoli Walls damaged walls break down decreased surface area for gas exchange Emphysema Carcinogens Tumor growth Lung cancer Carbon monoxide combines irreversibly with haemoglobin Carboxyhaemoglobin less oxygen transported.

XYLEM and PHLOEM Xylem Transports water and mineral ions up the plant.   

Continuous column, dead cells, lignin Mineral Ions absorbed through Active transport. Water is absorbed by Osmosis into root hair cell.

Phloem Transports Glucose [made during Photosynthesis] from leaves to other parts of plants. 

Sieve plates elements and companion cells or energy.

Transpiration  Water molecules are attracted to each other.  Transpiration stream in Xylem  Transpiration out of stomata Transpiration Stream Continuous column of water moving up the xylem from roots to leaves. Factors affecting Transpiration rate Increasing  HOT water evaporates faster  DRY increases the concentration gradient between leaf and the surrounding air.  WINDY water is blown off the leaf increasing concentration gradient  SUNNY stomata open to allow more CO2 into leaf.

C6 H12 O6 + 6O2  6H2O + 6CO2 Anaerobic respiration [Insufficient Oxygen]- Glucose  Lactate + [energy] Oxygen dept Oxygen required to breakdown lactate in muscles. Anaerobic Respiration [ Yeast]

Decreasing  

COLD water evaporates slower HUMID small Glucose Ethanol + Carbon dioxide C6 H12 O6  2 C2 H5 OH + 2 CO2

Respiratory system

concentration gradient between leaf and air



 

3.

STILL AIR water is not removed from surface of leaf NO SUN stomata close as no photosynthesis taking place.

Role of TRANSPIRATION STREAM    

Transport mineral Ions Keep plant cells turgid Cools the plant Supplies water for leaves for photosynthesis.

Blood Components    

White Blood Cells Platelets Clot the blood at the site of the wound.  [Soluble fibrinogen is converted to insoluble fibrin] Plasma Carbon dioxide, urea, amino acids, hormones, glucose Red Blood Cell  No nucleus, Biconcave disc shape to maximise surface area to volume ratio to transport more oxygen  Contain haemoglobin that binds with oxygen forming oxyhaemoglobin.

 

Blood enters right ventricle and leaves via pulmonary artery. 4. Blood flows to Lungs 5. Blood becomes oxygenated 6. Blood returns to the heart and enters the left atrium via pulmonary vein. 7. Left atrium contracts forcing blood through bicuspid valve into left ventricle. 8. Left ventricle contracts forcing blood into aorta. 9. Oxygenated blood lows around body and used in Respiration. Walls of Ventricles are thicker than atriums because they pump blood at high pressure. Walls of left ventricle are thicker than Right ventricle as they pump blood further and at high pressure

Arteries carry Blood AWAY from heart. Coronary Heart Disease [CHD] 

Coronary arteries supply heart with its own oxygen needs.

Immune System

Factors increasing chance of getting [CHD]

Pathogen prevention

   

  

Skin act as barrier. HCL destroys pathogens. Tears, eye lashes and nose hair trap.

White Blood Cells PHAGOCYTES Engulf/ Ingest pathogens and secrete digestive enzymes. LYMPHOCYTES recognise antigens on pathogens and secrete antibodies to destroy them.    

LABEL the pathogen so it is easily recognised by phagocytes. NEUTRALISES TOXINS. Causes bacterial cell to BURST open. Causes pathogens to STICK together.

Vaccinations Contain DEAD/ WEAKENED attenuated forms of the pathogen. 1. 2. 3. 4.

Dead pathogen injected. Lymphocytes recognise the antigens and produce antibodies. Memory cells are made. Produce antibodies much faster next time.

Vaccinations containing   

DEAD PATHOGENS whooping cough WEAKENED PATHOGENS TB and Measles ANTIGENS ONLY Influenza

Circulatory System

Sedentary lifestyle, High fat diet Smoking Stress Hereditary

Questions

Why reducing blood supply to heart muscle cells can cause a heart attack? Answer: Less oxygen, less aerobic respiration, anaerobic respiration, lactic acid, low pH level.

How our heart rate is increased? Answer: Adrenaline increases heart rate, when we exercise, our muscles produce carbon dioxide. Receptors in Aorta and Carotid artery detect this increase in Carbon dioxide. Electrical impulses are sent to medulla and accelerator nerve increases heart rate. ArteriesNarrow Lumen, Thick wall made of muscle and elastic fibres. Veins Large Lumen, Thin wall made of muscle and elastic fibres. Contain valves to prevent backflow of blood. Capillaries Narrow Lumen, Thin wall only one cell thick. Excretion removal of waste products of metabolism Waste gases produced Carbon dioxide, Oxygen Excretion in humans   

Sweat from skin Urea from Kidneys Carbon dioxide from Lungs

Ultrafiltration small molecules [ glucose, urea, water, ions] are forced out of the blood unto the bowman’s capsule under pressure. 

Proteins are too large to enter the bowman’s capsule so they stay in blood.

Selective reabsorption ALL GLUCOSE, some IONS, NO UREA move back into blood [requires energy] Movement of blood around body 1. Deoxygenated blood enters the right atrium through vena cava. 2. Right atrium contacts forcing blood through Tricuspid valve into right ventricle.

Osmoregulation Controlling the amount of water in blood.

LOW water consumption 

Hypothalamus detects low levels of water in blood.

  

Sends signal to pituitary gland which releases MORE ADH Walls od collecting ducts are then more permeable to water. Urine is concentrated, low in volume, dark in colour.

HIGH water consumption    

Hypothalamus detects high levels of water in blood. Sends signal to pituitary gland which releases LESS ADH. Walls of collecting ducts are then less permeable to water. Urine is dilute, high in volume, pale in colour.

Homeostasis Maintenance of a steady internal environment

   

Hormones chemical messengers which travel in blood. Difference between HORMONAL and NERVOUS responses. HORMONAL

NERVOUS

Involves chemicals carried in blood.

Involves electrical impulses.

Response SLOWER

Response FASTER

LONG-LIVED

SHORT-LIVED

WIDE SPREAD

VERY LOCALISED

Role of skin     

Sense organ for pain, touch and pressure Tough outer layer Controls heat loss Barrier-prevents entry of pathogens Prevents water loss

When body temperature is too HIGH   

Hairs lay flat [ less insulating air trapped close to body Vasodilation [arterioles dilate]MORE heat is radiated Sweat evaporates and cools the body

When body temperature is too LOW   

     

Central Nervous System [CNS] contains BRAIN and SPINAL CORD. Effector MUSCLE [contracts] /GLAND [secretes Hormones] Synapse Gap between two neurons 

Prepares body for ‘fight or flight’ Pupils dilate to allow more light to enter the eye Hairs stand up on end to appear more intimidating Breathing rate increases to allow more oxygen to enter body Heart rate increases to deliver more oxygen around body Blood diverted from gut to muscles.

Neurotransmitter diffuses across the synapse and binds postsynaptic membrane

Reflex Actions FASTER and INVOLUNTARY

Hairs stand up [ more insulating air trapped close to body] Vasoconstriction [arterioles constrict] LESS heat radiated Shiver [contraction of muscles release heat]

Effect of adrenaline on body

MUSCLE- receives kinetic energy TONGUE- receives chemical energy NOSE- receives chemical energy SKIN- receives kinetic and heat energy



STIMULUS  RECEPTOR  SENSORY NEURONE  RELAY NEURONE  MOTOR NEURONE EFFECTOR  RESPONSE [Involves electrical impulses and synapse]

Nervous Response 

STIMULUS  RECEPTOR  SENSORY NEURONE  CNS  MOTORNEURONE  EFFECTOR  RESPONSE

The EYE

Insulinsecreted by Pancreas and converts glucose to glycogen. Auxins [Plant hormones]



In a stem  Auxins concentrate on the side furthest from light  Cell elongation causes the stem to bend towards light. ColeoptilesCereal seedlings used to investigate tropisms.



Clinostats to negate the effect of gravity or light.



Stimulus change in environment 

Plants respond to LIGHT and GRAVITY

Tropisma plant’s response to directional stimulus Phototropism a plant’s response to light  

Stem=positive Roots=negative

Geotropism a plant’s response to gravity  

Stem=negative Roots=positive

Cornea refracts light Pupils to allow light into the eye Iris controls size of pupil with circular and radical muscles. Lensrefracts light Retina contains photoreceptors [RODS and CONES] which are light sensitive Rods sensitive in dim light Cones sensitive to colour Optic nerveconverts light signals into electrical impulses Sclera tough outer casing to protect the eye Choroidstops light reflecting around inside eye.

LENS The Nervous System Sense organs in Humans  

EYE- receives light energy EAR- receives sound and kinetic energy

Accommodation Changes that occur to lens to focus light from different distances Focusing on objects FARAWAY 1.

Lens THIN

2. 3.

Ciliary muscle RELAXES Suspensory ligaments TAUTEN

1. 2. 3. 4.

Focusing on objects NEARBY 1. 2. 3.

Lens FAT Ciliary muscles CONTRACT Suspensory ligaments STACKEN

Human reproductive system [female]     

Lots of light pupil CONSTRICTS Dim light pupil DILATES Sexual Reproduction fusion of gametes at fertilisation which produces genetically varied offspring.

 

Fertilisation Joining of two gametes [EGG + SPERM]

 

How a 32cell embryo is formed? Sperm and Egg join at FERTILISATION Zygote divides by MITOSIS 2cells 4cells8cells16cells32cells.

Strawberry runners Potato tubers

Testes make sperms and testosterone Sperm duct a tube that transports semen from testes to urethra Urethra transport semen and urine out of body Prostate Gland and seminal vesicles contribute to seminal fluid SPERM VAGINA  CERVIX  UTERUS  FALLOPIAN TUBE

Placenta   

Asexual Reproduction Involves one parent and much faster than sexual reproduction and produces genetically identical offspring.  

Ovaries Makes eggs and Oestrogen Fallopian tubes Deliver eggs to uterus [site of fertilisation] Uterus where ZYGOTE implants and embryo develops Cervix Entrance to Uterus Urethra Transports urine out of body

Human reproductive system [male]

ZYGOTE EMBRYO [ MITOTIC DIVISION]

1. 2. 3.

Seed coat bursts Radicle grows down Shoots grow up Food store is used up.

Supplies Foetus with Oxygen, glucose, amino acids. Removes Urea and Carbon dioxide and waste materials Produces PROGESTERONE

FSH [ Follicle Stimulating Hormone] Matures eggs in Ovary.

Sexual Reproduction in Plants

LH [ Lutenising Hormone] causes OVULATION

MALE parts of the flower [Stamen]

Oestrogen Responsible for secondary sexual characteristics

 

   

Anther Filament

POLLEN  Male gamete

Inhibits FSH production

FEMALE parts of the flower [Carpel]   

Stigma Style Ovary

Pollination Transfer of pollen from ANTHER to STIGMA. Seed Formation 1. 2. 3. 4. 5. 6.

Repairs uterus lining Progesterone [ Made in Corpus Luteum, Placenta] maintains the thickness of uterine lining. Testosterone [Men] supports the development of secondary sexual characteristics     

Pollen Lands on stigma Pollen tube grows down the style into ovary Male gamete fuses with female gamete Ovule becomes seed Ovule wall becomes seed coat Ovary becomes fruit

Self Pollination Pollen from a plant lands on stigma of the SAME plant.

Pubic and Arm pit hair Voice breaks Sperm production Widening shoulders Sexual drive develops

Protein Synthesis   

Insect pollinated    

Hips widen Breasts develop Pubic and armpit hair Sexual drive develops

Bright, Large and Colourful petals NECTARY provides sugar for insects Enclosed stigma and anther so insect is forced to pick up pollen Strong scent to Attract insects

GENOME entire DNA of and organism NUCLEUS controls the activities of the cell GENE section of DNA that codes for a protein

DNA double helix structure and made up of sugar [deoxyribose] phosphate backbone. Wind pollinated     

Anther and Stigma exposed Dull coloured and small petals Absence of nectary Small pollen grains, feathery stigma No scent

Germination [Conditions Warmth, Oxygen, Water]

Bases Adenine, Thymine, Guanine, Cytosine Nucleotide deoxyribose sugar, phosphate, Bases [ A, T, C or G]  

RNA Ribose sugar, Bases [ A, U, C, G ] URACIL and NO THYMINE  Single stranded DNA deoxyribose sugar  Double stranded

CODON a sequence of 3 bases found on a mRNA corresponds to a single amino acid.

Anticodon a sequence of 3 bases on tRNA that matches the complementary codon on mRNA. Protein synthesis stages 



Transcription  DNA unwinds to expose bases  Unpaired bases in nucleus match up with exposed DNA bases.  mRNA leaves nucleus and attaches to ribosome. Translationoccurs in Ribosomes  One end of tRNA has an anticodon and the other end has an amino acid attached.  Two amino acids join together using peptide bond.

Mutation a rare, random change in DNA of an organism. 



Can cause a change in DNA and therefore a change in proteins and the phenotype of an organism.  Duplication  Deletion  Substitution  Inversion Caused by Ionising radiation, UV, X-RAYS, CARCINOGENS [tar]

Allele different form of the same gene.

  ECOLOGY         



Genotype Alleles of an organism. Phenotype physical appearance of an organism. Homozygous  Two of same alleles. Heterozygous Different alleles. Recessive [dd] allele only expressed if the dominant allele is not present. Dominant [DD] allele is expressed even if only one is present. Codominance when both alleles are expressed. 

Example: Red Snap Dragon Plants o White flowers are codominant to red flowers. o When a white flower is crossed with a red flower, pink flowers are produced.

Mitosis used in GROWTH, REPAIR, CLONING, ASEXUAL REPROUCTION.

The bacteria reproduce and pass on these favourable alleles to future bacteria Soon the whole population of bacteria is resistant to antibiotics



Environment the total non-biological living components in a ecosystem [soil, water] Habitat space where particular organisms live Population all the organisms that belong to a particular species found in an ecosystem. Community the population of all species found within an ecosystem. Producer a plant that photosynthesises to produce food. Consumer an animal which breaks down dead material and recycles nutrients. Parasite an organism which lives in another organisms, feeding and causing harm Biodiversity variety of plants and animals found within an ecosystem. Biotic Factors [ Living]  Competition for food  Nesting sites  Disease Abiotic Factors [ Non-Living]  Soil pH  Temperature  Carbon dioxide  Number of daylight hours Biomass Mass of living material

Why only 10% of energy is transferred from one trophic level to next? 1. 2. 3. 4. 5.

Not all of the plant is eaten Some parts are indigestible Some form excretory products Respiration leads to loss of Carbon dioxide and water Maintenance of steady body temperature.

Carbon Cycle 1. 2. 3.

Meiosisused to make gametes.

4. 5.

4 Stages Prophase, Metaphase, Anaphase, Telophase.

6.

Carbon is absorbed by green plants for photosynthesis and used to make glucose and proteins. Plants respire releasing Carbon dioxide Plants eaten by animals and carbon becomes part of their bodies. Animals respire releasing carbon dioxide Plants and animals die and are decomposed by microorganisms which respire. Combustion of fuels release carbon dioxide

Chromosomes in cells formed Mitosis= Diploid/ Meiosis= haploid Cell divisions Mitosis= 1 / Meiosis=2 Species Individuals which reproduce to produce fertile offspring. Variation in species Due to GENETICS and ENVIRONMENT. Nitrogen Cycle Evolution

1.



2. 3.

Many organisms alive today, and many more which ae now extinct, first evolved from simple life forms which first evolved more than 3.2 Billion years ago

Natural Selection

4. 5.

1. 2. 3. 4.

6.

Variation within a species due to mutation Individuals better adapted more likely to survive and reproduce Alleles passed onto offspring Repeats over many generations.

How do BACTERIA become resistant to antibiotics? 

Some have mutations which make them more likely to survive

Nitrates in soil are absorbed by root hair cells by active transport. Nitrates used to build plant proteins Plants die and decompose and are converted to nitrates by nitrifying bacteria. Denitrifying bacteria converts nitrates into nitrogen Nitrogen fixing bacteria are present on root nodules of beans and peas and convert nitrogen gas into nitrates which are added to soil. Lightening and the Haber Process are other sources of nitrogen.

Human impact on environment   

Fertilisers are leached into rivers and streams Plants grow quickly due to nitrates ‘algal bloom’ Plants die due to competition for light.



Death pf plants provide lots of food for decomposers. o Decomposers feed off the dead plant material. o Decomposers and microorganisms use up oxygen in aerobic respiration o No oxygen means aquatic animals die.

 

Disadvantages   

Greenhouse gases Carbon dioxide, Methane, Water vapour, nitrous oxides. Effect of enhanced greenhouse gases       

Global warming Ice caps melt Sea levels rise Low lying land floods Loss of biodiversity Extreme weather Change in bird migration patterns



Damage the ozone layer Sulfur impurities in petrol releases sulfur dioxide when burnt Which makes sulfuric acid. [Acid rain] Nitrogen and Oxygen react in high temperatures found in car



1. 2.

Acid rain  damages trees, limestone buildings and makes lakes and ponds too acidic.

3. 4. 5. 6.

Carbon Monoxide released by incomplete combustion in car engines. Combines irreversibly with haemoglobin in red blood cells.

Deforestation Cutting down trees for fuel, wood or space.     

More carbon dioxide is released in atmosphere Animals habitats destroyed Leaching of nutrients due to lack of tree roots Soil erosion leads to widespread flooding and landslides Less transpiration which causes change in weather

How do glasshouses and Polythene tunnels increase crop yield?    

 

Allow natural light in during summer and provide artificial light during winter. Provide warmer environment than outside due to trapping heat energy and reducing convection. Can be heated electronically Provide humid atmosphere to reduce water loss by transpiration.

Adding fertilisers replaces leached or lost nitrates and mineral ions. Nitrates are used by plants to build proteins.

Pesticide chemical which kills pests Advantages   

Effective at controlling pests Readily available Easy to use

Disadvantages    

Expensive Persistent Stored in tissues of living organisms [bioaccumulation] and becomes more concentrated along a food chain Toxic and non-specific

Biological Control using animals to kill pests [ Ladybirds added to kill aphids] Advantages 

Non-toxic

Suitable conditions o NUTRIENTS a controlled supply to feed microorganisms o pH LEVELkept constant at optimum level by adding acid or alkali if necessary o AIR SUPPLY provides oxygen necessary for aerobic respiration o TEMPERATURE controlled to increase rate but prevent over-heating and denaturing o AGITATION microorganisms constantly stirred to give more exposure to nutrients and reduce temperature.

Fish Farming

engines Nitrogen oxides  Nitric acid



Never fully removes pests Introducing alien species can have undesired results Slow process

Fermenter A vessel containing microorganisms that are involved in fermentation reactions.

CFC’s  Found in AEROSOLS and FRIDGES.  

Targets specific pest only Self- sustaining

7.

Lots of fish kept together in tanks / enclosures Water quality constantly monitored to provide optimum conditions. Waste products are constantly removed Diet carefully controlled Fish isolated from predators to protect them Sorted by size to prevent bigger fish eating smaller fish of same species Fish with desirable characteristics selectively bred.

Advantages    

Control diet, oxygen levels Remove diseased fish or provide antibiotics Protect fish from predators Selective breeding

Disadvantages   

Increased risk of disease Antibiotics can enter food chain Pesticides used may be toxic to other animals

Selective breeding in plants    

Humans choose plants with desirable characteristics Cross pollinate select plants Plants with desirable characteristics are bred Process repeats over many generations

Genetic Engineering 

Insulin lowers our blood sugar levels after a meal

INSULIN making using BACTERIAL CELL 1. 2. 3. 4.

Cut open plasmid using restriction enzyme Use restriction enzyme to cut out insulin gene Insert insulin gene into plasmid using ligase enzyme Put bacterial cell into the fermenter

Recombinant plasmid plasmid with a gene inserted. Vector transport biological material from one place to other. [ mosquito in transmission of malaria] Plasmid    

Small circular pieces of DNA Isolated from bacteria Desired gene inserted into plasmid to create recombinant plasmid Recombinant plasmids inserted back into bacteria

Virus Bacteriophage are a type of virus Desired gene inserted into bacteriophage Bacteriophage attaches to cell walls of bacteria Injects its genetic material Desired gene taken up by bacterial DNA

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Genetically modifying plants Herbicide WEED killer Specific uses of genetically modified plants      

Extend shelf life Frost resistant ‘’golden rice’’ rice containing beta carotene that prevents night blindness Resistant to herbicides Modified tobacco plants produce hepatitis B antigens [potentially used to manufacture vaccines] Modified tobacco plants and soy beans produce antibodies to fight against diseases.

Transgenic organism genes are transferred from one species to another Cloning producing genetically identical offspring 1. 2. 3. 4. 5. 6.

Body cell removed from animal to be cloned Remove egg cell from animal of same species Enucleate both cells Insert nucleus rom body cell into empty egg cell [fuse with electric shock] Insert egg cell into uterus of surrogate mother Cell divides by mitosis to form embryo

Advantages Faster More offspring produced No need for two parents

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Cloning in plants 1.

Taking a cutting  Cutting is dipped in rooting powder and transferred from soil

2.

Micropropagation  Small parts of plant are obtained  Place into sterile, agar jelly containing nutrients and hormones  Provide optimum temperature, pH, water and carbon dioxide levels

Advantages  

Large numbers of cloned plants can be produced very quickly Can occur at any time of year

Cloning transgenic animals can be used to produce human proteins  

Cloning can be used to produce large number of animals These animals can then make human proteins.

Trypsin damages liver and lungs 

AAT destroys Trypsin o Transgenic sheep are genetically engineered to produce AAT in their milk.

NOTES WRITTEN BY NEERAJ LOHANA. Hope they help you �