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How can you usually make a reaction happen faster?
Raise the temperature
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What is a catalyst?
a substance which increases the speed of a reaction without being changed or used up in the reaction
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What are catalysts made up of?
Proteins, chains of amino acids
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What is weird about enzymes?
they have unique shape which fits into active site on substance in reaction. reaction will only be catalysed if substance fits enzyme.
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Why do enzymes need a certain temperature?
If they become too hot they denature, as bonds holding enzyme together breaks
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How does pH affect enzymes?
if its too high or low, interferes with bonds and changes shapes, denatures
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What do digestive enzymes do?
Break down the big molecules into small ones that can pass through the walls of the digestive system
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Where is amylase made?
salivary glands, pancreas, small intestine
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What does amylase do?
convert starch into sugars such as maltose and dextrins
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Where is protease made?
stomach (pepsin), pancreas, small intestine
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What does protease do?
converts proteins into amino acids
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Where is lipase made?
pancreas, small intestine
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What does lipase do?
converts lipids into glycerol and fatty acids
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Where is bile produced, stored and released?
produced in liver, stored in gall bladder, released into small intestine
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What does bile do?
neutralises stomach acid so enzymes work, emulsifies fats to give bigger SA for lipase
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What happens in salivary gland?
produce amylase in saliva
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What happens in large intestine?
excess water is absorbed from food
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What happens in stomach?
pummels food, produces pepsin, produces hydrochloric acid to kill bacteria and give right pH for protease enzyme
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What happens in pancreas?
produces protease, amylase and lipase enzymes, releases into small intestine
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What happens in small intestine?
produces protease, amylase and lipase to complete digestion, digested food is absorbed into blood
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What is respiration?
the process of releasing energy from the breakdown of glucose, which goes on in every cell
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What is aerobic respiration?
using oxygen, releases a lot of energy, most reactions happen in mitochondria
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What is the equation for aerobic respiration?
glucose + oxygen = carbon dioxide + water + energy
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What does respiration release energy for?
build up larger molecules from smaller, allow muscles to contract, mammals and birds keep temp steady, plants build sugars into amino acids into proteins
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What does physical activity do?
increases breathing rate, meet demand for extra oxygen, increases heart rate (as more co2 needs to be removed from muscles)
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How is glycogen used during exercise?
glucose from food stored as glycogen, each muscle has own store, some glycogen is converted back to glucose to provide more energy
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What is anaerobic respiration?
no oxygen, incomplete breakdown of glucose which produces lactic acid
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What is bad about lactic acid?
builds up in muscles, painful, causes muscle fatigue
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What is the equation for anaerobic respiration?
glucose = energy + lactic acid
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What is oxygen debt?
repay oxygen that didnt get to muscles, have to breath hard after done to get more. blood flows to muscles to remove lactic acid by oxidising it to co2 and water.
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How are enzymes used in biological detergents?
proteases and lipases break down animal and plant matter like food or blood. more effective at working at lower temperatures than other detergents
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How are enzymes used to change foods?
proteins in baby food are predigested using proteases to make it easier for baby, carbohydrases can turn starch syrup into sugar syrup
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How can enzymes change slimming products?
glucose syrup turned into fructose syrup using isomerase. fructose sweeter, can use less of it, less calories
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What are the advantages of enzymes in industry?
specific, only catalyse the reaction you want. lower cost and save energy due to lower temp and pressure. work for a long time, after initial cost can continually use. biodegradable so no environmental pollution
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What are the disadvantages of enzymes in industry?
some people can develop allergies, can be denatured by small inc in temp, susceptible to poisons and pH, must be tightly controlled, expensive to produce, contamination can affect reaction
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Where is DNA found?
in the nucleus, in chromosomes
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What is a gene?
a section of DNA
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How do cells make proteins and how do our genes determine this?
string together genes in a particular order, genes tell us what order. DNA determines what proteins the cell produces which in terms determines what type of cell
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How is DNA fingerprinting used?
forensic science, paternity testing
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What does mitosis do?
divides to make identical cells, for growth and repair
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How does mitosis work?
dna spread out in long strings, duplicates DNA and forms X shaped chromosome, each arm is duplicate. chromosomes line up and cell fibres pull apart. go to opp ends. membrames form and they become nuclei. cytoplasm divides to form two new cells.
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How is mitosis used other than growth and repair?
asexual reproduction
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How does sexual reproduction produce variation?
gametes get one copy of each chromosome, 23 from each to make 46
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How does meiosis work?
duplicates DNA so one arm of each chromosome is exact copy, pairs line up in centre of cell in first division, in second chromosomes line up again and arms pulled apart. get 4 gametes. 2 join at fertilisation and grows through mitosis.
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What are stem cells?
undifferentiated, develop into different types of cell depending on what instructions they're given
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Where are stem cells found?
early human embryos
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Why are stem cells from bone marrow not as good?
not as versatile, can only turn into certain cells
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How can stem cells help people with blood diseases?
Can be treated by bone marrow transplants, as bone marrow contains stem cells that can turn into new blood cells to replace faulty old ones
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How can embryonic stem cells help?
replace faulty cells in people, make beating heart muscle cells, insulin producing cells, nerve cells
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Why are people against stem cell research?
human embryos are potential life, should concentrate on finding solution without embryos
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Why are people OK with stem cell research?
curing people who already and exist and suffer have more rights than embryos, embryos used in research are unwanted from clinics and would have been destroyed
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What is XX and XY?
girl and boy
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What did mendel see in the plants?
height characteristic was determined by separately inherited units passed from each parent. ratios of tall and dwarf plants in offspring shows that T was dominant over t.
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What were Mendels conclusions?
characteristics are determined by hereditary units, passed on from both parents, one from each. they can be dominant or recessive, so if you get both the dominant will be expressed.
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What are alleles?
different versions of the same gene, letters are used to represent them
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What is homozygous?
when two alleles for a particular gene are the same
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What is heterozygous?
when two alleles for a particular gene are different
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What is genotype and phenotype?
genotype means what alleles you have. phenotype means the actual characteristic.
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What is cystic fibrosis caused by?
recessive allele, people with only one copy are carriers, for child to get it both parents must be either carriers or sufferers
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What is polydactyly caused by?
dominant allele, can be inherited if just one parent has it
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How can embryos be screen for genetic disorders?
In IVF, before being implanted can remove cells and analyse genes
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Arguments for embryonic screening?
help stop sufferig, there are strict laws to stop it going too far, during IVF most embryos destroyed anyway, treating disorders costs govt lot of money
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Arguments against embryonic screening?
pick desirable baby, rejected embryos destroyed, implies that people with genetic problems undesirable, screening is expensive
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How do fossils form in rocks by gradual replacement by minerals?
things which don't decay easily are replaced by minerals as they decay, forming rock like substance. surrounding sediment also turns to rock but fossil stays distinct
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How are fossils formed from casts and impressions?
organism buried in soft material like clay, clay hardens around it and organism decays
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How are fossils formed from preservation where no decay happens?
In amber and tar pits theres no oxygen or moisture so decay microbes can't survive. glaciers too cold. peat bogs too acidic.
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Why is the fossil record incomplete?
soft bodied organisms, destroyed by ecological activities
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Why will species become extinct?
environment change, new predator, new disease, can't compete, catastrophic event, new species
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What is speciation?
development of new species
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When does speciation occur?
when populations of the same species become so different they can no longer breed together to produce fertile offspring
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What is isolation and how does it lead to speciation?
a population of species are separated, possibly due to a physical barrier. conditions on the other side of the barrier will be slightly different and therefore different characteristics will be more common in each population
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How does natural selection lead to speciation?
wide range of alleles in population, those with characteristics better adapted to environment have better chance of survival, so alleles that control beneficial characteristics more likely to be passed on
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Other cards in this set

Card 2


What is a catalyst?


a substance which increases the speed of a reaction without being changed or used up in the reaction

Card 3


What are catalysts made up of?


Preview of the front of card 3

Card 4


What is weird about enzymes?


Preview of the front of card 4

Card 5


Why do enzymes need a certain temperature?


Preview of the front of card 5
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