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Flashcards

AQA GCSE Biology

Charlie Murray Science AS Level English 81 cards

Cards in this deck (81)

  1. 1What do muscular tissues do?Contract to bring about movement.
  2. 2What do glandular tissues do?Contain secretory cells that can produce substances such as enzymes and hormones.
  3. 3What do epithelial tissues do?Cover the outside of your body and your internal organs.
  4. 4What do epidermal tissues do?Cover surfaces and protect them.
  5. 5What 5 factors affect living organisms?Nutrients
    Temperature
    Amount of light
    Availability of water
    Availability of oxygen and carbon dioxide
  6. 6What physical factors can you measure by counting along a transect?Light levels
    Soil pH
  7. 7Function of a nucleusContains genes on chromosomes.
  8. 8What 2 things happen in the small intestine?1. Enzymes made in the pancreas flow into here.
    2. Soluble food molecules are absorbed into your blood and get transported in the bloodstream.
  9. 9What 3 things happen in the gut?1. The muscles of the gut squeeze undigested food onwards into large intestine.
    2. Helps break up your food into small pieces with a large SA for enzymes to work on.
    3. Mixes food with digestive juices so the enzymes come into contact with as much of the food as possible.
  10. 10What happens in the large intestine?Water is absorbed from undigested food into your blood.
  11. 11What can proteins act as?Structural components such as muscles and tendons
    Hormones such as insulin
    Antibodies, which destroy pathogens.
    Catalysts in the form of enzymes.
  12. 12What is a protein?Protein molecules are made up of long chains of amino acids.
  13. 13What are enzymes?large protein molecules
  14. 14What are enzymes involved in?1. Building large molecules from lots of smaller ones (e.g. proteins from amino acids)
    2. Changing one molecule --> another (e.g. glucose into fructose)
    3. BREAKING DOWN LARGE MOLECULES into smaller ones (e.g. insoluble food molecules --> small soluble molecules like glucose)
  15. 15How do enzymes work?The long chains of amino acids fold to produce a molecule with a specific shape that allows substrates to fit into the enzyme protein.
  16. 16Effect of pH on enzyme actionChange in pH affects the forces that hold the folded chains in place, so changes shape in molecule.
    Active site is lost.
  17. 17Why do foods need to be digested?So they can form smaller, soluble molecules that can be absorbed and used by your cells.
  18. 18Digesting carbohydratesWhat breaks it down? Amylase
    Where is amylase produced? Mouth, small intestine, pancreas.
    Where is it broken down? Mouth and small intestine.
    What is it broken down into? Sugars
  19. 19Digesting proteinsWhat breaks it down? Protease
    Where is protease produced? Stomach, pancreas and small intestine
    Where is it broken down? Stomach and small intestine
    What is it broken down into? Amino acids
  20. 20Digesting fatsWhat breaks it down? Lipase
    Where is lipase made? Pancreas and small intestine
    Where is it broken down? Small intestine
    What is it broken down into? Fatty acids and glycerol
  21. 21Reasons for respiration1. Build up large molecules from smaller ones to make new cell material e.g. sugars, nitrates, other nutrients built up into amino acids into proteins.
    2. So muscles can contract - so animals can move.
    3. Keep bodies at a constant temperature.
  22. 22The effect of exercise on your body1. Heart rate increases and arteries supplying blood to your muscles widen. Increases supply of oxygen + glucose to muscles.
    2. Increases rate of CO2 and lactic acid being removed from body.
    3. Breathing rate increases, more oxygen brought into your body and picked up by red blood cells.
    4.
  23. 23What is anaerobic respiration?Respiration without oxygen.
    Glucose is incompletely broken down to form lactic acid.
  24. 24What is the oxygen debt?The amount of oxygen needed to oxidise the lactic acid to CO2 and water.
  25. 25Why does sexual reproduction lead to new varieties of plant?Gametes join.
    Mixing of DNA.
    One copy of each gene comes from each parent.
  26. 26What is a cell?The basic building block of a living organism.
  27. 27What is a nucleus?The part of the cell that contains genetic info.
  28. 28What is a chromosome?A thread-like structure holding genes.
  29. 29What is DNA?Chemical from which all chromosomes are made.
  30. 30What is a gene?A short section of DNA controlling a characteristic.
  31. 31What is an allele?A different version of the same gene.
  32. 32What is a dominant allele?An allele that controls the development of a characteristic when it is present on only 1 of the chromosomes.
  33. 33What is a recessive allele?An allele that controls the development of characteristics only if the dominant allele is not present.
  34. 34What is mitosis needed for?Growth, repair, replacement and asexual reproduction.
  35. 35Arguments for using stem cellsOffers 1 of the best chances of finding treatments for conditions.
    Generally uses spare embryos from infertility treatments that would be destroyed anyway.
    Embryos created from adult stem cells would never become babies.
    Could use stem cells from umbilical cord blood of newborn babies.
  36. 36Arguments against using stem cells.May cause further problems e.g. development of cancers.
    Unethical - embryos can't give permission to be used in experiments/treatments.
  37. 37Who was Mendel?Carried out breeding experiments using peas.
    First person to suggest separately inherited factors (now called genes).
    Found that characteristics were inherited in clear+predictable patterns.
  38. 38Why weren't Mendel's theories accepted?No-one knew about genes or chromosomes, hadn't seen them through a microscope yet.
    Insufficient evidence.
  39. 39What is DNA made up of?Combos of 4 different chemical bases grouped into 3s.
    Each group of 3 bases codes for a particular amino acid.
    Order of bases controls order of amino acids so controls which protein is made.
  40. 40HomozygousAn individual with 2 identical alleles for a particular characteristic e.g. DD, dd
  41. 41HeterozygousAn individual with different alleles for a characteristic e,g, Dd
  42. 42GenotypeDescribes genetic makeup of an individual regarding a particular characteristic e,g, Dd, dd
  43. 43PhenotypeDescribes physical appearance of an individual regarding a particular characteristic e,g, dimples, no dimples.
  44. 44What is polydactyly? Dominant or recessive?Born with extra fingers or toes.
    Caused by dominant allele so can be inherited from only 1 parent.
  45. 45What is Cystic Fibrosis? Dominant or Recessive?Organs become clogged up by thick, sticky mucus which stops them from working properly. Reproductive system's affected - infertile.
    Caused by recessive allele.
  46. 46Arguments for screening embryosGives parents a choice on whether or not to keep the baby.
    Reduces number of people with CF in population.
    Cures 'disfigurement' (polydactyly)
    Reduces health care costs
  47. 47Arguments against screening embrysNot worth it - polydactyly isn't life-threatening.
    Could cause miscarriage/damage embryo.
  48. 48Way that fossils can be formed: Hard partsBits that don't decay easily (bones, teeth, claws, shells) form fossils.
  49. 49Ways that fossils can be formed: Lack of decayConditions needed aren't present e.g.
    1. Little/no oxygen present
    2. Bacteria that causes decay killed off by poisonous gases.
    3. Temperature's too low so organisms are preserved in ice.
  50. 50Ways that fossils can be formed: ReplacementHarder parts of animal/plant replaced by other minerals over a long period of time.
  51. 51Ways that fossils can be formed: Trace fossilsFossil footprints, burrows, rootlet traces and droppings are formed.
  52. 52Why oh why is the fossil record incomplete?1. Early life forms were soft-bodied so left little fossil trace.
    2. Most dead organisms didn't become fossilised because right conditions for fossil formation were rare.
    3. Geological activity destroyed many fossils.
  53. 53causes of extinctionChanges to environment
    New predators
    New diseases
    New + more successful competitors
    A single catastrophic event e.g. massive volcanic eruption, collision with asteroid.
  54. 54How a new species arrivesISOLATION - Species seperated by barrier e.g. mountain, river, ocean, sea.
    GENETIC VARIATION caused by range of alleles in different environments.
    NATURAL SELECTION - Advantageous characteristics caused by alleles are 'selected'.
    SPECIATION - Species become too different to be able to interbreed successfully.
  55. 55How do fossils provide evidence for the theory of evolution?They show that things have changed over time.
    Fossils have similar features to present-day species.
  56. 56Definition of extinctAll members of a species have died out.
  57. 57What is a species?A group of organisms that can breed together successfully.
  58. 58Why does the stomach produce hydrochloric acid?1. Enzymes of the stomach work best in acidic conditions.
    2. It kills most of the bacteria that you take in with your food.
  59. 59What does bile do?1. Stored in gall bladder until it's needed.
    2. Neutralises acid from the stomach on the food that's come into the small intestine from the stomach.
    3. Emuslifies fats, creating much bigger SA for lipase enzymes to work on.
  60. 60Sampling Along a Transect1. Take tape measure/marked rope or string
    2. Place quadrat
    3. Record the presence of each plant type.
    4. Place quadrat at next point (regular intervals)
    5. Repeat 3 or more times.
  61. 61What happens to your food molecules after they've been completely digested?Leave your small intestine.
    Pass into your bloodstream...
    ... to be carried around the body to the cells that need them.
  62. 62In what 2 places is food NOT digested?1. The liver
    2. The pancreas
  63. 63Enzymes in the home - Biological Detergents (Explanation, Advantages and Disadvantages)Proteases and lipases break down proteins and fats in stains.
    Advantages: Can give a cleaner wash and work better than non-biological detergents at lower temperatures. (So use less electricity)
    Disadvantages: Can irritate delicate skin
  64. 64Enzymes in Industry - Baby foods (Explanation, Advantages and Disadvantages)Proteases can pre-digest proteins in baby foods into amino acids.
    Advantages - Easier for baby's digestive system to cope, easier to get the amino acids they need from the food.
    Disadvantages - Allergic reactions
  65. 652 Advantages of Using Enzymes in Industry1. Catalyse reactions at relatively low temperatures and normal pressures - CHEAP TO RUN.
    2. Pure enzymes use the substrate more efficiently.
  66. 662 Disadvantages of Using Enzymes in Industry1. Costs to control conditions (keep temperature down and keep pH carefully controlled)
    2. Pure enzymes are more expensive to produce.
  67. 67Ways Enzymes are Used in Medicine: TO DIAGNOSE DISEASEIf you're liver's damaged or diseased, some of your liver enzymes may leak out into your bloodstream.
    Doctors can test your blood for enzymes to see if your liver's really damaged.
  68. 68Ways Enzymes are Used in Medicine: TO DIAGNOSE AND CONTROL DISEASEPeople with diabetes have a lot of glucose in their blood and their urine.
    A test strip (containing a chemical indicator and an enzyme) is placed in a urine sample.
    Enzyme will catalyse breakdown of any glucose in urine.
    Strip changes colour if products of this reaction are present.
  69. 69Ways Enzymes are Used in Medicine: TO CURE DISEASE (3 examples)1. A damaged pancreas cannot make enzymes - take extra enzymes, particularly lipase, to help you digest food. In special capsules so they won't be digested.
    2. To reduce damage done to <3 muscle after a <3 attack, enzyme called streptokinase will be injected and dissolve clots in the arteries of the <3.
    3. Enzyme can speed up breakdown of a particular amino acid so cancer cells can't get any and die.
  70. 70How are mitochondria adapted for aerobic respiration?They have a folded inner membrane to provide a large SA for enzymes involved in aerobic respiration.
  71. 71How can you tell how active a cell is?The number of mitochondria in the cell will tell you
  72. 72What is glycogen and how is it used in the body?It is a carbohydrate stored in the muscles.
    It can be converted rapidly back to glucose to use during exercise.
  73. 73What is glucose used for in aerobic respiration?Provides the energy to make your muscles contract.
  74. 74Enzymes in Industry - SyrupCarbohydrases are used to convert starch into sugar syrup.
  75. 75How are chromosomes found in body cells?In pairs
  76. 76What happens in mitosis?Copies of the genetic material are made.
    Cell divides ONCE to form 2 identical body cells.
  77. 77How many sets of chromosomes do body cells have? How many sets of chromosomes do gametes have?2 sets
    1 set
  78. 78What happens in meiosis?Copies of the genetic info are made
    Cell divides TWICE to form FOUR gametes, each with a single set of chromosomes
  79. 79What are fossils?The 'remains' of organisms from many years ago, which are found in rocks.
  80. 80Word Equation for Anaerobic RespirationGlucose ----------> Lactic acid (+small amount of energy)
  81. 81What can fossils show?How new species are formed
    How new organisms arise
    How species become extinct

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AS Level Science Flashcards on AQA GCSE Biology, created by Charlie Murray on 08/05/2015.
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