Biology b2

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  • Created by: Amirahhh
  • Created on: 19-03-17 19:33
Enzymes
they make chemical reactions happen which make us work.
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catalysts
A catalayst is a substance which increases the speed of a reaction,without it being changed or used up in the reaction.
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enzymes are catalysts
They produce enzymes that speed up the chemical reaction. Enzymes are biological catalysts
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Enzymes & Protiens
All enzymes are protiens. Protiens are made up of chains of amino acids. These chains are folded into a specific shape. it allows the enyme to do its job.
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As well as catalysts, protien act as :
structual parts of tissues, hormones, and antibodies.
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Enzymes have special shapes
chemical reactions ususally involve thinngs either being split apart or joined together. Every enzyme has a specific shape that fits in to the substance involved in a reaction.
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Enzymes have special shapes 2
Enzymes are realy picky they usually only catalyse one reaction. This is because for the enzyme to work, the substance has to fit its special shape. If the substance doesnt match the enzyme shape then the reaction wont be catalysed.
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Enzymes need the right tempreture
A higher tempreture inccreases the rate of reaction involving an enzymes. But if it gets too hot, someof the bonds holding the enzyme together break. The enzyme is denatured
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Enzymes need the right pH too
If the pH is too high or low it affects the bond holding the enzyme together. This changes the shape and denatures the enzyme.
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Enzymes in stomach
The stomach produces an acid called hydrochloric acid. Enzymes in the stomach work best in these acidic conditions.
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Big molecules
starch,protiens,and fats are big molecules. They are too big to pass through the wallsof the digestion system. Big molecules are broken down into smaller ones by the digestive enzymes
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Small molecules
sugars,amino acids,glycerol and fatty acids are small molecules. They can easily pass through the walls of the digestive system.
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Amylase
Amylase is made in the salvary glands,pancreas and small intestine. It works in the mouth and small intestine. Starch is broken down by amylase and enzyme and turned into sugars
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Protease
Protease is made in the stomach,pancreas and small intestine. it works in the stomach and small intestine. Protein is broken down by protease and enzymes and turned into amino acids.
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Lipsase
Lipase is made in the pancreas and small intestine. It works in the small intestine. Lipd is broken down by lipase and enzymes and turned in to glycerol and fatty acids.
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Bile
Bile neutrailes the stomach acid. It is produced in the liver. It is stored in the gall bladder before its released into the small intestine. Bile is a alkaline. The enzymes in the small intestine work best in these alkaline conditions.
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Respiration is not breathing in or out.
Respiration is the process of releasing energy from glucose which goes on in every cell.
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Aerobic respiration
is repirationn using oxygen. Most reactions in aeobic respiration happens inside the mitachondria .
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Equation for aerobic respiration
Glucose + oxygen -> carbon dioxide +water + energy
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4 examples for what the energy in aerobic respiraion is used for
To bulid larger molecules from smaller ones, in animals to allow the muscles to contract,in mammals and birds the energy is used to keep their body temp steady. In plants,to bulid sugars,nitrates and other nutients into amino acids and protein.
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Exercise increases the heart rate
Your muscles cells use oxygen to release energy from glucose-They repire aerobically. The Energy is used to contract the muscles.
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When we excerise
our muscles need more oxygen and glucose. Extra C02 needs to be removed from the muscle cells. For it to happen, the blood has to flow at a faster rate.
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This is why exercise :
increases our breathing rate,make us breathe more deeply, and increases our heart rate
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Glycogen is used during exercise
Our muscles store glucose as glycogen. During hard exercise,mucles use glucose quickly. So some of the stored glycogen is changed back to glucose to give more energy.
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Anaerobic respiration is used if theres not enough oxygen
When we do hard exercise our bodu cant supply enough oxygen to out muscles. Anaerobic respiration is repiration withought oxygen.Its the incomplete broken of glucose.
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Why anaerobic is not the best way to convert glucose into energy
This is beacuse it makes lactic acid. The lactic acid builds up in the mucles and get painful..Lactic acid alo casues muscle fatigue-the muscles get tired and stop contracting as well. The blood flowing through our muscles removes the lactic acid.
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Enzymes are used in Biological detergents.
Enzymes aew the biological ingrediants in biological detergents. They're mainly protien-digesting enzymes (protease) and fat digesting enzymes ( lipsaes). Biological detergents are more effective at working at low temps than other types of detergants
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Enzymes are used to change foods.
The protein in baby foods are pre digested as they are broken down by protein digesting enzymes. Carbohydrate-digesting enzymes can eb used to turn starch syrup into sugar syrup. It is also used in slimming prodcuts.
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Using enzymes in industry saves money
They speed up reactions without the need for hihg tempretures and pressured.
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Advanatge of enzymes in industries
Using low tempretures and pressures means a lower cost as it saves energy
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Disadvanatge of enzymes in industries
Enzymes can be denatured by even a small rise in tempreture. Also enzymes can be expesnive to produce.
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Chromsomes are really long molecules of DNA
Dna conatins all the instrauctions to put an organism together and make it work. DNA is found in the nucleus of animals and plant cells . Its found in really long molecules called chromosomes.
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DNA
It has a a double helix structure. A gene is a sections of DNA.
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Mitosis
Makes new cells growth and repair
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How mitosis works
a cell with two sets of chromosomes. The chromosomes make a exact copy of its self. Then they line up in the middle and then the chromosomes split making two identical daughter cells.
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Asexual reproduction uses mitosis
For example strawberry plants can reprodcue this way
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Meiosis
Makes new sex cells. Gametes are sex cellls E.g sperm cells, egg cells. They only have one set of chromsomes
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How meiosis works
Parent cells copies itself,similar chromosome pairs line up in the middle, sections of dna swap and chromosome pairs divide and then divide again.
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Meiosis (what they have)
has sexual reproduction,for making new sex cells, not identical,haploid, 23 chromosomes.
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Mitosis (what they have)
for repair and growth,diploid,idetical,46 chromosomes
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Two types of stem leaves( stem leaves can turn into any type of cell)
Embryonic stem cell-Specialised cells found in early embryos.
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stem cells may be able to cure many diseases
scientists can extract stem cells from very early human embryos and grow them. These stem cells could be used to replace faulty cells in sick people.
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Some people are against stem cell research
people feel that embroys should be used for expermeints since each one is a potencial human life. Others link that curing people who are suffering is more imporant than the rights of embryos.
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Some people are against stem cell research 2
They argue that the embroys used in reserach are usually unwanted ones from clinics id they werent used for reserch they would be destroyed. But people think scientists shoulld be finding other sources of stem cells to use.
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X and Y chrmomosmes
Chromosomes are really long molecules of DNA. There are 23 pairs of chromosomes in every human body cell. The 23rd pair is labelled ** and XY.They're the two chromosomes that deicde your sex.
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male chromosomes
All men have X and Y chromosomes:XY The Y chromo causes the male characteristics.
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female chromosomes
All women have two X chromosomes:**. Having two X's allows female characteristsics to develop.
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sperms & egg
Sperm cells have an X or a Y chromosomes. All eggs have one X chromosomes.
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Genetic diagram type 1 ( 4 boxes)
Put all the possible gamets from on parent down the side, and those from the other parenta along the top. The pair of letters in the square show the possibllle offspring you can end up with.
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Genetic diagram type 2 (spider diagram)
At the top the parent. The middle show the possible gametes that are formed. One from the femalecombined with one from the male.The criss-cross lines show all the possible way it could combine. The possibleoff spring is shown at the bottom.
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Genetic diagram show the possible genes of offspring
Different genes controll the development of different chracateristics E.g eye colour. There can be different versions of the same gene these are called alleles.
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Alleles
They give different versions of chracteristics E.g blue eyes or brown eyes . We have 2 alleles for dif genes.
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alleles
They can be domiant or recessive. If we have 2 domiant alleles the domminant chracteristcs will be shown.If we have 1 domiants and 1 recessive onlt the domiant one will be shown
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Alleles 2
To show a recessive characteristsic, both alleles for a gene have to be recessive.
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How to use and understand gentic diagrams
In a genetic diagram, you show all of the possible alleles for a particular characteristic. There will be two alleles from one parent, and two from the other parent, making four altogether.
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How to use and understand gentic diagrams 2
You then draw lines to show all the possible ways that these alleles could be paired in the offspring. There will be four possible ways, but some or all of them could be repeated.
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gentic diagrams 3
In genetic diagrams, the dominant allele is shown as a capital letter, while the recessive allele is shown as a lower-case letter.
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Gregor Mendel-monk in 1800
He did gentic experiemnts wiht pea plants. He studied how the charcateristics in plants were passed on from parents to their offspring.
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His expermient
His expermeints had shown that the height chracteristsics in the pea plant was determined by seperetly inherited uits passed down on from each parent.
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Mendal reached 3 important conclusions
Characteristics are determind by inheritience units , Units passed on from both parents one each, Units can be domiant or recessive if it had both domminant and recessive the domiant one would be expressed.
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Cystic Fibrosis is caused by a recessive Allele
Cystic fibrosis is a gentic disorder of the cell membrane. It is caused by a fauly recessive allele of a single gene.
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Why is it fauly
because its recessive,people with only one copy of the allele wont show the symptons pf the disorder-They're known as carriers.For a child to have a chance of carrying it both parents must be carriers or sufferers.
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Polydactyly is caused by a domiant Allele
Polydactyly is a genetic disorder where a babys born with extra toes or fingers. Its caused by a faultydomiant allele of a single gene.
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Inherting Poludactyly
it can be inherited if jsut one parent caries a fauly allele. The parent that has the faulty allele will be a sufferere too,since the allele is domiant.
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Embryos can be screened for genetic diorders.
During in vitro fertilisation embryos are fertalsied in a lab and then put into the mothers wob. Before they're put into the mother you can remove a cell from each embryo and look at its genes.
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Embryos can be screened for genetic diorders 2
Many gentic disorders can be picked up in this way,such as cystic fibrosis. Embryos with good alleles are then put into the mother and the bad ones are distroyed .
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Against embryo screening
They may be a point when everyone wants to screen them so they pick the best one eg blond hair. The embryos with bad allelesare destroyed wen they could have been delevoped into humans. It is expensive
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For embryo screening
help stop people suffering,There are laws to stop it going far eg they cant chose sex of baby,treating disorders cost money.
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Fossils-remains o plants and animals
They provide evidece that organisms lived ages ago. Fossils form in rocks in ones of these 3 ways : gradual replacment ,casts and impressions and preservation.
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Gradual replacemnt by minerals
things like teeth,shells, and bones dont easily decay. This means they can last a long time when buried. When they do decay, they get relplaced by mineras. The minerals form a rock like substance shaped like the orgianl hard part.
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Casts and impressions
Fossil can be formed when an organismis buried in a soft material like clay. The clay hardens aroud it and argansim decays. It leaves a castof itself. Things like footprints are pressed inotsoft materials. This leaves the impression when they harden
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Preservation
Decay microbes only work if theres oxygen,moisture,warmth and the right pH. In some substances these condition arent all present so decay doesnt happen. So decay organisms *** survive.
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why we *** be sure how life began
First life forms appeared in a swamp or under the sea on earth but these hyptheses *** be supported or disproved because theres a lack of valid and reliable evidence.
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Evolution
Species beocme extinct for these reaosn-enviroment change,new predators,new disease,cannot commpete,catastrophic event and new species.
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speciation is the development of a new species
Isolatin is where populations of species are seperated E.g due to physical barrier.
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Isolation can casue speciation :
Things like flood nd earthquakes can cause barriers that isolate some individual from the main population
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Isolation can casue speciation : 2
Conditons on either side of the barrier will be slitely differnt e.g they must have differnt climates. because the enviroment is diffent on each side,differnt characteristics will become more common in each population.
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Card 2

Front

A catalayst is a substance which increases the speed of a reaction,without it being changed or used up in the reaction.

Back

catalysts

Card 3

Front

They produce enzymes that speed up the chemical reaction. Enzymes are biological catalysts

Back

Preview of the back of card 3

Card 4

Front

All enzymes are protiens. Protiens are made up of chains of amino acids. These chains are folded into a specific shape. it allows the enyme to do its job.

Back

Preview of the back of card 4

Card 5

Front

structual parts of tissues, hormones, and antibodies.

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Preview of the back of card 5
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