Exam questions and answers

Transcription

1 B2 Exam questions and answers

2 Topic you need to know about: Chapter 1: cells, tissues and organs Chapter 2: organisms in the environment Chapter 3: enzymes Chapter 4: energy from respiration Chapter 5: simple inheritance in animals and plants Chapter 6: old and new species

3 Chapter 1: cells, tissues and organs 1. What three components (organelles) are found in plant cells but not animal cells? 2. What does a 1. specialised Cell wall, chloroplasts cell mean? and vacuole 3. Where is DNA found in a cell? 4. What is the function of 3. the In cell the nucleus membrane? 5. What is the function 4. of It chloroplasts? is selectively permeable (also known as semipermeable) photosynthesis and it decides occurs. what substances can go 6. What green liquid is found in the chloroplasts? in or 5. out. It is where light energy is 7. What is found in the vacuole? absorbed 6. chlorophyll for photosynthesis 8. What is the function of 7. the Cell vacuole? sap (it contains sugars, salts and water) 9. How are root hair cells adapted 8. It keeps for their cell function? firm They Xylem Baking absorb are bread! made water up and of empty minerals dead cells and 10. What is the difference between xylem and phloem? from the soil. 11. What is the function of a microscope? leaves. Phloem is made up of living tissue and 12. Do bacterial cells have a 12. nucleus? NO! 11. bacterial Microscopes cells don t magnify have an a image nucleus, their 13.What can we use yeast for? tissue. 15. The (make movement it look bigger). of particles Things from such a high as 14.What does a yeast cell look of a like? plasmid. cells 16. Organs need to are be made magnified up of so lots that of concentration to a low concentration through a they cells. can The be definition seen easily. of an organ is 15. Describe diffusion? semi-permeable membrane. groups of tissues (that means 16.What are organs made from? different types of tissues) working 17. Name four organs in plants. together for a particular function. 18.What is a cell? 2. A cell that has a particular function, e.g. a root hair cell is a plant cell that absorbs water and minerals whereas a palisade cells are plant cells where most transport water from the roots to the stem and the transports food substances (like glucose) to growing DNA is free to roam in the cytoplasm or in the form 17. Root (provides anchorage and where water and minerals are absorbed from the soil), stem (holds the leaf upright), leaf (where photosynthesis occurs) and flower (involved in reproduction). 18. The basic unit of life

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5 Draw an animal cell and plant cell The blue is found in both cells and the three words in black are only found in plant cells.

6 Draw a yeast cell

7 Draw a bacterial cell

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9 A- remember, diffusion is from a high concentration to a low concentration.

10 Cytoplasm Cell membrane nucleus

11 Cell wall Cell membrane genes / genetic material / chromosome Cytoplasm

12 Cell wall Cell membrane Cytoplasm vacuole

13 Cytoplasm Nucleus

14 any two from: two required for 1 mark P R T

15 1. has) cell wall (1) 2. (has) vacuole or large / permanent vacuole do not allow chloroplasts because even though it is a plant cell, it is found underground (it is a root cell) so it cant photosynthesise if it is not exposed to the sun!

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17 Root hair

18 No - diffusion if from a HIGH concentration to a LOW concentration (i.e. DOWN a concentration gradient) - The sulphate ions would LEAVE the root by diffusion

19 Nucleus Cytoplasm Cell membrane

20 any two from: (contain mitochondria many (mitochondria) respiration (occurs in mitochondria)

21 any two from: transport up / against concentration gradient / low to high concentration uses energy use of protein / carrier

22 large(r) surface area accept have carriers release energy or make ATP do not accept makes energy

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24 any two from: large surface / area or many villi or have microvilli accept big surface / area thin surface or thin wall or surface 1-cell thick or capillaries near surface or permeable or partially permeable accept they are thin do not allow thin cell wall many blood vessels or many capillaries or capillary network or good blood supply ignore constant blood flow owtte ignore extras eg moist or reference to gases have enzymes ignore release enzymes accept reference to lacteal as 5 th point allow reference to having mitochondria

25 Because the plant cells have a higher concentration of mineral ions than the pond water. Diffusion happens from a HIGH concentration to a LOW concentration. So the plant cells couldn't absorb the mineral ions, they would actually lose the mineral ions by diffusion and they would go into the pond water. The only way the plant cells could ABSORB the mineral ions from the pond water is by ACTIVE TRANSPORT which happens from a low concentration to a high concentration

26 Nucleus Cell membrane

27 - energy released or energy transferred or respiration allow provides or gives energy do not allow produces energy or makes energy - near to the site of movement or energy available quickly - accept allows more mitochondria to fit in (mitochondria) packed (around filament) or efficient arrangement

28 for tube 1: - expands or gets firmer or bigger or inflates - it gains water - because the concentration of water is less than its surroundings make sure answer is about water movement and not sucrose solution for tube 2: - gets floppy or flaccid or contracts - it loses water - because the concentration of water is greater than its surroundings

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30 A B diffusion

31 Cell wall cell membrane Genetic material cytoplasm

32 Topic you need to know about: Chapter 1: cells, tissues and organs Chapter 2: organisms in the environment Chapter 3: enzymes Chapter 4: energy from respiration Chapter 5: simple inheritance in animals and plants Chapter 6: old and new species

33 Chapter 2- organisms in the environment 1. What is the word 1. carbon equation dioxide for + photosynthesis? water (+ light energy) glucose + oxygen 2. What is the chemical equation 2. 6CO 2 + for 6H 2 O photosynthesis? (+ light energy)c 6 H 12 O 6 + 6O 2 3. Do plants respire? 3. yes! All living things need to respire (MRS GREN remember!) 4. What is a variegated leaf? the green parts that would photosynthesise. 5. One of the products of photosynthesis is glucose. What can it be turned into? 5. Plants need the glucose they produce during photosynthesis for respiration. 6. What is the 7. The 6. test Any quickest for excess starch? way glucose to measure in plants the is rate converted of photosynthesis into starch. To is to test for Glucose can be converted into insoluble starch, insoluble fats or 7. How can we measure starch, the add the rate brown rate which iodine of photosynthesis oxygen solution. (the If product) starch in the is is present, produced. laboratory? it will turn insoluble 8. A oils. 8. What is a limiting blue-black. factor that 14. reduces advantages: the rate bigger of photosynthesis. yield, growth of This crops could be: factor? light, 9. When carbon an dioxide enzyme all year or (which round temperature. is (and a protein) when certain no longer crops works are properly 9. What does the because 11. term Starch is denature has is produced been put mean? in from the extra wrong (excess) condition glucose. (e.g. it When has been a plant 10. What does insoluble overheated) be 13. into controlled The amount produced starch. mean? and to so grow of crops out the crops produced. of season, they usually sell for 15. independent- protein all unfolds year round. more), save change, money dependentmeasure, and energy and doesn t on transport function. can be used in respiration. 11. Starch is an energy store. costs- control- What crops keep does produced the that same mean? locally instead of having (always more 12. What are greenhouses and to be than polytunnels? transported one) in from other countries. 13. State what yield means. disadvantages: expensive to run, lots of energy needed (lighting, heating etc). 14.State the advantages and disadvantages of manipulating environmental conditions in which plants grow. 15.What is the difference between independent, dependent and control variable? 4. Plants that have leaves which have green AND white bits. It is only Greenhouses It cant be or dissolved. polytunnels This are is important places where as extra the environment glucose is turned can needs more energy, it breaks down the starch into glucose again so it

34 Chapter 2 continued- communities of organisms and their environment 1. Mean is the average, median is the middle number (we have to organise them into order first) and mode means the 1. What is the difference between mean, median and mode? most = common. 15/5= 3 (30 is an anomaly) 2. Work out the mean: 2, 3, 3. A 4, thermometer 2, 4, How can temperature be 4. measured? Chemical analysis 5. Light 6. meter Bio means or light living, sensor. diversity means a 4. How can the amount of nutrients in soil be measured? range of something. So biodiversity 5. How can the amount of light be measured? means a range of living things. 6. What is biodiversity? 7. What does sampling mean? 8. What is a quadrat and what is it used for? 9. State the difference between reliability and validity. 10. Name two sampling Instead These methods. are of counting used to investigate something in CHANGES a WHOLE in habitat, populations e.g. 11. What does bias the mean number and how of woodlice, can this we be choose avoided? an area and only count 10. Sampling from A Reliability is quadrat one trying area to is happens to find a metal another. out when or the wooden A number there piece is or of of more plastic string a particular of or frame something. a cord organisms that can So 12.What is a 13. transect? Succession the number if that SMALL area- this is called SAMPLING. in an area placed be for 11. by used Try only example, in not counting an is sampling to area- the the process get certain greater e.g. human (remember you by patches manipulation the want which number to sampling and find communities then of involved. out is quadrat using counting how the colonise Random the counts number the 13. Describe succession. an ecosystem numbers Then we use the number and ESTIMATE the number of to estimate of number done, sampling the daisies the and total. of and changes better are then organisms systematic the from in estimation. replaced a sampling small field area, to over avoid a rocky time by such bias seashore, other using placing a quadrat so you communities woodlice in the TOTAL AREA. However, place and what Validity quadrats. then a areas cord means estimating do along you whether this sample? way. you number Then have of you answered organisms place quadrats the in question the total at or - You can regular area). not. do this So The intervals it by links quadrat random with and can sampling- reliability. sample be anything them. you If can you from use have 10cm, a computer more 50cm reliability, to get 1m random along you numbers should each and side. have then more this validity. will generate coordinates and you use these numbers to find out where you should place your quadrats. - You can also do this by systematic sampling- a grid is placed on the area you want to find out the total number of organisms of, and then you mark out the quadrats at equal points.

35 Carbon dioxide Oxygen

36 carbon dioxide concentration - since atmospheric concentration very low / value give e.g. 0.03% - allow carbon dioxide used up - temperature high - allow if light chosen as a factor - light intensity high allow If temperature chosen as a factor

37 6 6 6 any two of (presence of) chlorophyll or (amount of) chloroplasts accept green leaves (or other green parts) (sufficient) light (intensity) (light) of a suitable wavelength any light other than green light control by osmosis the movement of gases Through stomata * near the upper surface * contain (a great) many or more chloroplasts * (so) contain the most chlorophyll

38 + light = + photosynthesis + light = + photosynthesis to a limit limit depends on temp/co2 levels + CO2 = + photosynthesis + temp = + photosynthesis

39 P, R or T (give two only)

40 oxygen light chloropyll Carbon dioxide water

41 Sugar/carbohydrate It can be stored OR It is insoluble Either of: - Uses it in respiration - Turns it into cellulose - Turns it into protein - Turns it into lipids photosynthesis One from: - They are thin - They have a large surface area - They are flat - They have stomata - They have air spaces - They have chloroplasts - They have veins

42 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 1 mark each for any of the following ideas: lower CO 2 concentration lower light intensity decrease water availability alter light wavelength or colour accept more green light

43 April June

44 - Does not contain chlorophyll - which is needed to absorb light or energy

45 e.g. mussels/caddis/ loach water Carbon dioxide light

46 water oxygen Keep temperature constant

47 absorbs light/to produce food e.g. has chlorophyll/chloroplasts has elongated shape to absorb light

48 water oxygen

49 keep temperature constant

50 Continued from previous slide (same question) a factor other than temperature is limiting do not accept water 1 eg carbon dioxide

51 Continued from previous slide (same question) a factor other than temperature is limiting do not accept water 1 eg carbon dioxide

52 any one from: (type of / amount of) soil / minerals / nutrients / ph amount of water / time of watering space between plants / plants and wall time for growth

53 any one from: increase / give light increase temperature / make warmer increase / give CO 2 any two from: add fertiliser/ nutrients / minerals / named cheaper allow grow faster / more grown better quality / flavour ignore size available all year accept converse if clear that answer refers to use of British tomatoes allow Fair Trade

54 any two from: greater distance or more food miles or more transport idea of more needed only once transport needs (more) energy / fuel reference to eg greenhouse effect / global warming / pollution / CO 2 release / carbon footprint ignore ozone

55 Water Oxygen

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57 water oxygen Chlorophyll (cant get a mark for saying chloroplast as it is a component not a substance. You can get a mark if you say chlorophyll which is found inside chloroplasts though light intensity / temperature is high enough for higher rate or light / temperature is not limiting low CO 2 available or not enough CO 2 available or rate would be higher with more CO 2 temperature allow water / rain allow (too) cold / hot as a minimum allow wave length / frequency / colour ignore ions ignore heat

58 carbon dioxide/co 2 through the roots/root hairs do not accept leaves oxygen

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60 glucose can be used for respiration by the plant 1 production of fat or oil 1 production of cellulose 1 production of proteins

61 2.2

62 Topic you need to know about: Chapter 1: cells, tissues and organs Chapter 2: organisms in the environment Chapter 3: enzymes Chapter 4: energy from respiration Chapter 5: simple inheritance in animals and plants Chapter 6: old and new species

63 Use of Enzyme Detail reaction Chapter3- catalysed Advantage enzymes where Disadvantage produced enzymes Amylase salivary glands, pancreas, small Biological (a carbohydrase) Contain proteases starch Helps sugars 1. Amino to remove acids Might 2. intestine irritate some detergent and lipases. Work stains - 3. Proteins A transition are found metal people s in that nuts, speeds skin. seeds The up and a meats - chemical 5. Enzymes The hormone reaction are made up of proteins not better at lower Lower6. temp An enzyme needed stomach, (like insulin enzymes a catalyst pancreas, is a protein may it speeds go small into up a protease proteins amino acids metals (like catalysts) temperatures than Reduces - reaction, Antibodies energy but are it is proteins found rivers intestine and the harm body and the made 1. What non-biological is a protein made up of? - up Proteins of a protein) lipids fatty costs acids 7. Something + are that made fits water in into the life. an ribosomes enzyme Using and low can 2. lipase Name five uses/functions of proteins 8. The -be Enzymes broken best in our conditions. down are body. or proteins two Enzymes or more work substrates best at detergents. So pancreas, glycerol temperature small intestine may not can kill body 3. What is a catalyst? be temperature- added together 37 to degrees make a C. bigger different reduces energy pathogens on clothes. molecule. enzymes 9. When work an best enzyme at different no longer works ph s. e.g. and 4. How costs. is an enzyme similar to a catalyst? proteases cannot 11. lipids catalyse work fatty best a reaction. at acids a low and ph It glycerol and has lipases become by lipases 5. What is an enzyme different from 12. work unfolded best a catalyst? Proteins amino acids (proteases) Baby Proteases used in Helps baby s 13. Carbohydrates/starch digestive so higher the active ph s. May site trigger has been glucose allergic ruined. 6. What does the term biological catalyst (carbohydrases mean? 15. or amylases) food baby food to predigest the food. system to cope 7. What is a substrate? alkaline Creates with (because an acidic reactions food environment that comes in from the the protein. 8. What does optimum mean? Slimming intestine and the enzymes in the small 9. What The does enzyme denature mean? Fructose is sweeter Enzymes such as intestine work best at alkaline conditions). foods 10. Describe isomerase digestion can in humans? than glucose, so a isomerase are 11. What convert do lipids glucose break into down to smaller and how? amount is expensive to produce 12.What fructose. do proteins Fructose break is down needed. to and the This how? food makes enters (used it! to convert 13.What sweeter do carbohydrates so you need break fructose down to syrup and a how? glucose into fructose) 14.What less are of the it. functions of bile? useful ingredient in 15. What is the function of hydrochloric slimming foods. acid in digestion? 16.What are the uses of enzymes in industry? 4. Enzymes also speed up chemical reactions. 14. It makes conditions in the small intestine stomach needed is acidic for and enzymes then it to goes work to properly the small Bile is produced in the liver, stored in the gall bladder and goes into the small intestine when

64 What are enzymes? Enzymes are proteins found in the body. They speed up chemical reactions like digestion. We can refer to enzymes as biological catalysts All enzymes are specific (they only act on one type of reaction) A lot of them end in ase, but not all of them Enzymes are not used in the reaction, they just speed it up. So they can be re-used catalase amylase trypsin pepsin

65 How much can you remember so far? proteins 1. Enzymes are. this means that you can t use different enzymes on the same reaction. 2. All enzymes have an active site. 3. Enzymes can be re used as they don't take part in the reaction other than speeding it up. 4. Another term for an enzyme is a biological catalyst.

66 Label me

67 Summary of Enzyme Location and Action Enzyme Location Catalyses the breakdown of: Carbohydrase (Amylases) Protease Lipase salivary glands pancreas small intestine stomach pancreas small intestine pancreas small intestine starch into sugars proteins into amino acids lipids (fats and oils) into fatty acids and glycerol

68 mouth or saliva starch Maltose or glucose Small intestine Fats/lipids Fatty acids or glycerol salivary accept pancreas pancreas accept small intestine or ileum

69 -work at low temperatures / save energy - work at low or atmospheric pressures / need less expensive equipment any two from: easily broken down by high temperature / low ph difficult to separate from water-soluble products very expensive to buy

70 pancreas produces lipase which breaks down / digests fats into fatty acids and glycerol liver produces bile / hydrogen carbonate which neutralises acids / makes alkaline provides optimum / best / most effective ph for lipase / enzyme action bile emulsifies fats / description increasing the surface area for lipase / enzyme to act on any five for 1 mark each (digestion is in stomach / liver / pancreas penalise only once)

71 pros e.g.: gum trees survive therefore less soil erosion therefore food webs not disrupted if no culling, whole Koala population may die easier to cull because Koalas are difficult to catch cons e.g.: Koala s right to life / ethical issue better to transfer to reserves on mainland than kill could use tranquillisers to catch without killing could allow population to stabilise naturally max 4 of the above; max 3 pros or cons.

72 digested / broken down / made soluble by protease enzyme in stomach in small intestine / from stomach / from pancreas into amino acids amino acids / small molecules absorbed into blood

73 10

74 liver

75 liver mouth or salivary glands or small intestine or pancreas Pancreas (accept small intestine) stomach or small intestine or pancreas - teeth breakdown food accept chewing - amylase or saliva (breaks down starch)

76 liver

77 protease amino acids

78 any two from: neutralises acid / makes conditions alkaline / raises ph enzymes (in small intestine) work (more/most effectively) or stop/prevents enzymes being denatured emulsifies fats/lipids or description of emulsification do not accept breakdown unqualified larger surface area

79 Topic you need to know about: Chapter 1: cells, tissues and organs Chapter 2: organisms in the environment Chapter 3: enzymes Chapter 4: energy from respiration Chapter 5: simple inheritance in animals and plants Chapter 6: old and new species

80 Chapter 4- energy from respiration 1. One of the seven life processes. It is a chemical reaction 2. Energy! that Energy occurs allows in all us of to our WORK!! 3. C cells in the 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O mitochondria 4. glucose + oxygen to generate carbon energy. dioxide + water (+ energy) 5. Mitochondria is the site of respiration where energy 1. What is respiration? 7. you need 2. What does respiration generate? is 6. a generated. constant amount of glucose in your blood. If 8. you Respiration have - extra, Building needs it is large oxygen turned molecules and into produces glycogen from small carbon which ones is 3. What is the chemical insoluble. dioxide. equation - These Muscle for gases respiration? contraction are also transported for movement around the 4. What is the word equation blood Your Respiration for body respiration? gets with fitter little/no and oxygen you are better able to 5. Why are mitochondria can be known converted as the into powerhouses glucose. of a cell? 6. What can we use the When so during your energy you cells activity. exercise, can get from respiration you more need oxygen lots for? of and energy. glucose So and you the do 7. What is glycogen and more carbon 13. how respiration Lactic dioxide is it acid can produced? (which be removed generates faster. energy). Heart rate is So how Most you glucose fast need of the more lactic heart time, glucose! acid beats. muscles (+ energy) get the energy needed to 8. What is the difference between breathing rate and heart rate? so contract Breathing glycogen form rateis aerobic converted the rate respiration. into which glucose. However, you exchange if you the 9. What happens if we suddenly exercise start regularly? to exercise vigorously, your muscle cells 10. What is anaerobic respiration? body. supply of oxygen. won t respiration. have enough oxygen to keep contracting hard. So 11. What is the difference you However, start between to it do produces anaerobic aerobic energy and respiration. anaerobic FASTER This than respiration? is aerobic when you 12. What is the word 15. equation Once respiration. we for stop anaerobic working hard respiration? after vigorous exercise, lungs increases. 13. What are the products our muscles of anaerobic are still breathing respiration? deeply. This is because It provides the muscles with the energy they need to 14. What are the advantages our bodies of are anaerobic trying to gain respiration? back the extra oxygen. contract. 15.What does an oxygen debt mean? If you don t - have Keeping enough body glucose temperature in your constant/steady blood, glycogen Heart provide rate- the your increased heart rate blood increases supply that during muscles exercise need 14. Energy is generated fast and it means we can still do Anaerobic gases exercise carbon for respiration dioxide a bit longer and produces oxygen even less from if we energy the havent air than into got a aerobic your big During exercise, breathing rate increases- the volume haven't of oxygen got and enough carbon oxygen. dioxide The moving process in releases and out of energy your without the need for oxygen to break down the glucose.

81 (aerobic) respiration carbon dioxide water (vapour)

82 respire Oxygen/glucose Oxygen/glucose blood Carbon dioxide/heat Carbon dioxide/heat

83 water vapour more carbon dioxide less oxygen glucose

84 oxygen lactic

85 oxygen lungs oxygen Lactic acid

86 Topic you need to know about: Chapter 1: cells, tissues and organs Chapter 2: organisms in the environment Chapter 3: enzymes Chapter 4: energy from respiration Chapter 5: simple inheritance in animals and plants Chapter 6: old and new species

87 Chapter 5- simple inheritance in plants and animals 1. What is a cell? 1. The basic unit of life. 2. What is a karyotype? are 3. normal In the nucleus. 4. Strands chromosomes of genetic and information one pair that are sex is MADE chromosomes. 3. Where is our DNA found? of 5. DNA Sections and CONTAINS of DNA that genes. code for our 4. What is a chromosome? 6. characteristics, Different forms e.g. of the eye same colour. gene. You 5. What is a gene? might 7. mitosishave two produces alleles body for eye cells colour for growth but you and repair. 6. What is an allele? only TWO 8. The express daughter cells produced (show) cells one. are from produced mitosis and or there meiosis. 9. A sex cell is ONE cell division. 10. Specialised The daughter cells- cells e.g. are sex identical cells, root to the hair parent cells, 7. Name two ways in which cells can divide and describe each of them. cell. The neurones daughter etc. are cells all are specialised known as cells. DIPLOID as they 8. What is a daughter cell? have two sets of DNA. 9. What is a gamete? Meiosis- 11. Cells produces that CAN gametes differentiate from diploid into cells. other The types of 10. Describe what a differentiated daughter cells. 12. Bone cells Differentiated cell marrow are is. known stem cells as cells HAPLOID can t do be as this. used they But to have treat stem half cells 11. What is a stem cell? the amount can. leukaemia. 13. We of can Embryos DNA The treat have research from diseases embryonic the is parent on-going stem cell. cells. to In try humans, That s and treat why 12.How can stem cells be meiosis used some diseases children 16. Gregor occurs scientists human for from Mendel in spinal the their was treatment? think testes injuries parents. a monk. He spent many years 18. polydactly- having more and fingers we can etc. ovaries. or toes studying inheritance using peas. use them He was to treat trying human to have 13.What are the ethical issues disease- 19. alleles behind Cystic but from the fibrosis- that our use would mum of affects destroy and dad. stem cells? the membranes Different embryo. pairs of alleles their life 14. What is variation? Some the can first produce countries generation different have and banned then characteristics. embryonic reappear stem in the cell next 15.What is a punnet that square? disease. marrow, generation which (even can be if their used to parents treat didn t blood show diseases. this for 16.What did Gregor Mendel do? life. characteristic). shows whether the individual has one or two copies The couple of the He can concluded allele. prepare if that their it child was due may to have something the disease called (e.g. 17. Some alleles are dominant Some and some recessive. What does this mean? inherited alleles are factors. recessive- We now where call the these characteristic genes. 18. Give examples of decide dominant to go disorders through abortion. 19. Give examples of May recessive be pair used they disorders have to test didn t that for allele. understand. other alleles- e.g. eye colour or 20.What is screening. State the pros and cons. 2. A picture that shows all of the chromosomes. 22 chromosomes 15. Showing the possible chromosome combinations in 17. If We we have are chromosomes transferring cells from from our mum one person and dad. to So another, we Huntingtons- it may be rejected a disease or that that affects person the will nervous need medication system 20. If a couple understand has a history why of some a genetic characteristics disease, the would womans disappear embryo in can be taken Luckily, and screened stem cells to see are if even the found potential in adults- baby has in the alleles bone for Some alleles are dominant- the characteristic they code research as they think this could have been a potential save money or have counselling to support them) or the couple may they A code lot of for his only work shows was ignored when both until chromosomes after his death of the as intelligence or sporting ability, aborting babies that are not normal - some may see this as unethical.

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89 eggs ovaries sperm testes sexual gametes fertilisation asexual

90 peas

91

92 breed (together) accept have same number of chromosomes do not accept have the same number of genes to produce fertile offspring

93 male or testes testes or male ovary or ovaries gametes fertilisation fetus or zygote or embryo genetic information or genes or chromosomes or DNA do not accept characteristics by itself (comes) from two parents accept from both parents

94 Remember- mitosis produces the same thing as the parent cell (above)

95 Remember meiosis produces GAMETES (sex cells) so they have HALF the amount of DNA. You could have kept the dark ones or the light chromosomes (makes no difference, as long as you show you now have half!)

96 Topic you need to know about: Chapter 1: cells, tissues and organs Chapter 2: organisms in the environment Chapter 3: enzymes Chapter 4: energy from respiration Chapter 5: simple inheritance in animals and plants Chapter 6: old and new species

97 Chapter 6- origins of life on Earth 1. What is a fossil? 2. How can fossils be formed? that once Radioactive lived. dating methods 3. How can we find out how old fossils are? 4. Fossils provide evidence in of. the environment. genes. 5. When do scientists believe in over the Earth environment. time. was formed? 6. When do scientists believe can t life occur. of Earth began? 7. What does extinction mean? 8. State what natural selection mean? 9. State what mass extinction? 10. What is speciation? 1. Fossils are the remains or traces left of organisms evolution- Billion billion years because ago or we can use million them years to show ago how - 7. Mineral Reduction replacementof a species minerals to zero. in This organisms have changed over the years. the ground could happen because 8. Organisms replace organisms that minerals in cant are the evolve best adapted hard parts fast enough to the of the skeleton to changes environment 9. Where many survive, DIFFERENT reproduce species and pass can die their at the such same 10. Where as time- the bone this one or may species shells occur may and if evolve this there prevents is into a drastic another decay. change species - Mummification- too cold or too acidic- then decay - Moulds and casts- the dead organism may be pressed into a soft sediment to form a cast. - Trace fossils- footprints etc.

98 variation / mutation 1 individuals with characteristics most suited to environment survive, allow survival of the fittest 1 genes passed to next generation or these individuals reproduce 1

99 there is a lack of valid / reliable evidence because the early organisms were soft bodied or because remains were destroyed by geological action

100 populations of salamanders became isolated / separated 1 by areas between mountains 1 there was genetic variation in these isolated communities 1 natural selection acted differently on these isolated communities 1 eventually resulting in interbreeding being no longer possible and so new species have been formed 1

101 any two from: similar in size to Emperor penguin or bigger than all penguins large size is adaptation to cold climate since less heat loss per unit of body volume or smaller surface area /volume ratio

102 any four from: mutation / variation produces smaller wings / fatter body must be linked to mutation / variation wings no longer an advantage since no predators allow wings / flight not needed as no predators wings no longer an advantage since food on ground allow wings / flight not needed as food on ground fatter body can store more energy when fruit scarce successful birds breed / pass on genes

103 any one from: evidence has all gone no scientists on island at time to record evidence no records (from sailors)

104 any two from: streamlined / shape reduces friction / long and thin / smooth surface OWTTE fins / flippers / tail / paddle do not accept arms or legs structures that push against water

105 fossils / teeth / bones / skeleton / foot prints allow cave drawings do not accept scientists have seen them only (some) bones remain / soft parts have decayed accept no-one has ever seen one allow no photos, no pictures, no drawings any two from: hunted by human (new) predator allow more predators (new) competitor (new) disease environment changed / named environmental change allow natural disaster prey extinct / loss of food supply ignore not enough food

106 Biology data analysis questions

107 plants with all mineral salts grew best plants with mineral salts but no nitrate grow better than without any mineral salts

108 ((mean) mass) increases up to 7 / 8 units (of light) then levels off light limiting factor up to 7 / 8 units for photosynthesis other factor / temperature limiting above 7 / 8 units

109 rubber plant/fern Because it can tolerate low levels of light