Exam questions and answers [PDF]

B2 Exam questions and answers

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

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

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.

Draw a yeast cell

Draw a bacterial cell

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

Cytoplasm Cell membrane

nucleus

Cell wall

genes / genetic material / chromosome

Cell membrane

Cytoplasm

Cell wall Cell membrane Cytoplasm vacuole

Nucleus Cytoplasm

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

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!

Root hair

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

Nucleus

Cell membrane Cytoplasm

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

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

large(r) surface area accept have carriers

release energy or make ATP do not accept ‘makes energy’

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 5th point • allow reference to having mitochondria

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

Nucleus

Cell membrane

- 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

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

A B

diffusion

Cell wall

cell membrane

Genetic material cytoplasm

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

Chapter 2- organisms in the environment 1. carbon dioxide water (+ light energy) → glucose + oxygen What is the word equation for +photosynthesis? What is the chemical equation 2. 6CO2 +for 6H2Ophotosynthesis? (+ light energy) C6H12O6 + 6O2 3. yes! All living things need to respire (MRS GREN remember!) Do plants respire? 4. Plants that have leaves which have green AND white bits. It is only What is a variegated leaf? the green parts that would photosynthesise. One of the products of photosynthesis is glucose. What can it be turned 5. Plants need the glucose they produce during photosynthesis for into? respiration. 6. What is the test for starch? 7. The 6. Any quickest excess way glucose to measure in plants theisrate converted of photosynthesis into starch. To is to test for Glucose can be converted into insoluble starch, insoluble fats or measure starch, the add rate brown at which iodine oxygen solution. (the Ifproduct) starch isispresent, produced. it will turn 7. How can we measure the rate of photosynthesis in the laboratory? insoluble oils. 14. advantages: bigger yield, growth of crops 8. A factor that reduces the rate of photosynthesis. This could be: blue-black. 8. What is a limiting factor? 9. When an enzyme (which is a protein) no longer works properly all year round (and when certain crops are light, carbon dioxide orpolytunnels temperature. 11. 12. Starch Greenhouses is produced or from extra are (excess) places where glucose. the environment a plant can 10. It cant be dissolved. This is important as extra glucose is turned 9. What does the term mean? because is ‘denature’ has beenofput in the (e.g. it When has produced out of wrong season,condition they usually sell forbeen 13. The amount crops produced. needs be controlled energy, tosogrow it crops breaksall down yearthe round. starch intofunction. glucose again so it into starch. 15. more independentchange, dependentoverheated) and the protein unfolds and doesn’t 10. What does insoluble mean? more), save money and energy on transport canmeasure, be used in respiration. controlkeep thethat samemean? costscrops produced locally instead of having 11. Starch is an ‘energy store’. What does (always more than one) to be transported in from other countries. 12. What are greenhouses and polytunnels? 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?

1. 2. 3. 4. 5.

Chapter 2 continued- communities of organisms and their environment 1. Mean is the average, median is the middle number (we have to between organise them into order first) and mode means the 1. What is the difference mean, median and mode? most common. 2. 2+3+4+2+4= 15/5= 3 (30 is an anomaly) 2. Work out the mean: 2, 3, 4,thermometer 2, 4, 30 3. A Chemical analysis 3. How can temperature be 4. measured? 5. Light6.meter or lightliving, sensor. Bio means 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. 7. of counting something in a WHOLEinhabitat, e.g. 10. Name two sampling methods. 12.Instead These are used to investigate CHANGES populations the number ofhappens woodlice, we anmore areaof and count 11. What10. does bias and how can this bewooden avoided? from one area to another. Achoose piece is of string or aonly cord is can 9.mean Reliability when there something. So Sampling 8. A is quadrat trying to is find a metal out or the number or of plastic a particular frame organisms that 13. Succession the process by which communities colonise the number if that SMALL areathis isof called 12. Whatinisana area transect? placed innot anis areae.g. youpatches want to find out howSAMPLING. the number for example, the greater the number quadrat counts 11. Try to getcertain human manipulation involved. Random be by used only counting in sampling (remember sampling and then is using counting the the numbers an ecosystem and are then replaced over time by other Then we use the number and ESTIMATE the number ofyou 13. Describe succession. of daisies changes from asampling field area, to avoid a rocky seashore, so done, the better the estimation. sampling and systematic bias in placing to estimate number the total. of organisms in a small such as using a quadrat communities woodlice in the TOTAL AREA. aareas cord along this way. Then you place quadrats at or Validity means whether you haveof answered the quadrats. However, place and what then estimating do you sample? the number organisms in question the total intervals and sample them. not. SoThe itbylinks with reliability. If can you have more reliability, - You canregular area). do this quadrat random can samplingbe anything you from use 10cm, a computer 50cm to get 1m you should have more randomalong numbers eachand side. then thisvalidity. 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.

Carbon dioxide Oxygen

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

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

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

P, R or T (give two only)

oxygen

light

chloropyll

Carbon dioxide water

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

6CO2 + 6H2O → C6H12O6 + 6O2

1 mark each for any of the following ideas: lower CO2 concentration lower light intensity decrease water availability alter light wavelength or colour accept more green light

June

April

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

e.g. mussels/caddis/ loach

water Carbon dioxide light

water

oxygen

Keep temperature constant

absorbs light/to produce food

e.g. has chlorophyll/chloroplasts has elongated shape to absorb light

water

oxygen

keep temperature constant

Continued from previous slide (same question)

a factor other than temperature is limiting do not accept water 1 eg carbon dioxide

Continued from previous slide (same question)

a factor other than temperature is limiting do not accept water 1 eg carbon dioxide

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

any one from: • increase / give light • increase temperature / make warmer • increase / give CO2 • add fertiliser / nutrients / minerals / named

any two from: • 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’

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 / CO2 release / carbon footprint ignore ozone

Water

Oxygen

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 CO2 available or not enough CO2 available or rate would be higher with more CO2 temperature allow water / rain allow (too) cold / hot as a minimum allow wave length / frequency / colour ignore ions ignore heat

carbon dioxide/CO2

through the roots/root hairs do not accept leaves

oxygen

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

2.2

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

Enzyme Use of Detail enzymes

reactionChapter3catalysed Advantage enzymes

where produced Disadvantage

salivary glands, pancreas, small Amylase starch → sugars 1. Amino acids Biological Contain proteases Helps to remove Might irritate some (a carbohydrase) intestine 2. A transition metal speeds up a meats detergent and lipases. Work stains people’s skin. The - 3.Proteins areare found inthat nuts, seeds and 4. 5. Enzymes also made speed up up of chemical proteins reactions. not chemical reaction stomach, pancreas, small better at lower Lower temp needed enzymes may go into 6. An enzyme (like a catalyst it speeds up a The hormone insulin is a protein metals (like catalysts) protease proteins → amino -acids butare it isproteins found inand theharm body and intestine temperatures than Reduces energy rivers themade - reaction, Antibodies of a protein) 1. What is a protein of? - up Proteins are made ininto thelife. ribosomes 7. Something that fits an enzyme non-biological costs water Using and lowcan lipids made → up fatty acids + 8. The best conditions. Enzymes best at can pancreas, intestine - Enzymes are proteins be broken down or two orsmall morework substrates 2. lipase Name five uses/functions of proteins in our body. detergents. So glycerol temperature may not kill body temperature37 degrees C. different be added together to make a bigger molecule. 3. What is a catalyst? reduces energy pathogens on clothes. enzymes work best at different pH’s. e.g. 9. When an enzyme no longer works and 4. Howcosts. is an enzyme similar to a proteases catalyst? 11. lipids acids and by lipases work fatty best at a low pH and lipases cannot catalyse a reaction. Itglycerol has become 12. Proteins amino acids (proteases) 5. What is an enzyme different from a catalyst? work best atsohigher pH’s. 13. Carbohydrates/starch glucose unfolded the active site has been ruined. Helps baby’s digestive Proteases used in May trigger allergic Baby 14. It makes conditions in the small intestine 6. What does the term ‘biological catalyst’ mean? (carbohydrases or amylases) system to cope with baby food to prereactions 15. Creates an acidic environment the the food 7. What is a substrate? alkaline (because food that comesinfrom protein. stomach for enzymes work digest the food. stomachneeded is acidic and then it to goes to properly the small 8. What does optimum mean? intestine and theEnzymes enzymes insuch the small The enzyme is sweeter Slimming as 9. What does denature mean? Fructoseintestine work best at alkaline conditions). isomerase can in humans? than glucose, so a foods10. Describe are in the gall digestion Bile is produced isomerase in the liver, stored convert glucose smaller amount is 11. What do lipids breakinto down to and how? tointestine producewhen bladder and goesexpensive into the small fructose. Fructose needed. This makes 12. What do proteins breakisdown to andthe how? food enters (used it! to convert sweeter so you need fructose syrup a 13. What do carbohydrates break down to and how? glucose into fructose) less it. functions of bile? useful ingredient in 14. What areofthe slimming foods. 15. What is the function of hydrochloric acid in digestion? 16. What are the uses of enzymes in industry?

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

pepsin

trypsin

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

Label me

Summary of Enzyme Location and Action Enzyme

Carbohydrase (Amylases)

Location

salivary glands pancreas small intestine stomach

Protease

pancreas

Catalyses the breakdown of:

starch into sugars

proteins into amino acids

small intestine pancreas Lipase

small intestine

lipids (fats and oils) into fatty acids and glycerol

mouth or saliva starch

Maltose or glucose

Small intestine Fats/lipids

salivary accept pancreas

pancreas accept small intestine or ileum

Fatty acids or glycerol

- 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

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)

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.

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

10

liver

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)

liver

protease

amino acids

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

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

Chapter 4- energy from respiration 1. One of the seven life processes. It is a chemical 2. Energy!that Energy allows toour WORK!! reaction in allus of cells in the 3. C6H12O6 +occurs 6O2 → 6CO + 6H 2 2O 4. glucose + oxygen → carbon dioxide + water (+ energy) mitochondria to generate energy. 5. Mitochondria is the site of respiration where energy 1. What is respiration? 7. you need 6. a constant amount of glucose in your blood. is generated. 8. Respiration needs oxygen and produces carbon 2. What does respiration generate? If you have - extra, Building it is large turned molecules into glycogen from small which ones is dioxide. These gases are also transported around the 3. What is the chemical equation for respiration? insoluble. - Muscle contraction for movement 9. Your gets fitter and oxygen you are better able to 4. What is the word equation for respiration? Ifblood. you don’t -body have Keeping enough body glucose temperature in your constant/steady blood, glycogen 10. Respiration with little/no Heart rateheart rate during exercise provide the increased bloodincreases supply muscles need can be converted into glucose. 5. Why are mitochondria known asyour the powerhouses of athat cell? soduring your can get glucose activity. When youcells exercise, youmore needoxygen lots ofand energy. So and you the do 6. What can we use the energy from respiration for? carbon dioxide can be removed faster. Heart rate is 13. Lactic acid more respiration (which generates energy). 7. What is glycogen and how is produced? how fast the heart beats. 11.12. Most glucose ofit the lactic time, acid muscles (+ energy) get the energy needed to So you need more glucose! 14. Energy is generated fast and it means we the can still do 8. What is the difference between breathing rate and heart rate? Breathing ratethe rate at which you exchange contract form aerobic respiration. However, if you …so glycogen is converted intoeven glucose. exercise for a bit longer if we the havent got ayour big 9. What happens if wesuddenly exercise regularly? gases carbon dioxide and oxygenless from air into Anaerobic start respiration to exercise produces vigorously, energy your muscle than aerobic cells supply of oxygen. body. won’t respiration. have enough oxygen to keep contracting hard. So 10. What is anaerobic respiration? During exercise, breathing rate increasesvolume you However, start toitdo produces anaerobic energy respiration. FASTER This than is the aerobic when you 11. What is the difference between aerobic and anaerobic respiration? of oxygen and carbon dioxide moving inreleases andexercise, out of your haven't respiration. got enough oxygen. The process energy 12. What is the word15. equation for anaerobic respiration? Once we stop working hard after vigorous lungs the oxygen deeply. to break down the glucose. ourwithout muscles areneed stillfor breathing This is because 13. What are the products ofincreases. anaerobic respiration? provides the muscles with thethe energy need to ourItbodies areanaerobic trying to gain back extrathey oxygen. 14. What are the advantages of respiration? contract.

15. What does an ‘oxygen debt’ mean?

(aerobic) respiration

carbon dioxide

water (vapour)

respire Oxygen/glucose

Oxygen/glucose blood

Carbon dioxide/heat Carbon dioxide/heat

water vapour more carbon dioxide less oxygen

glucose

oxygen

lactic

oxygen

lungs

oxygen Lactic acid

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

Chapter 5- simple inheritance in plants and animals basic unit life. all of the chromosomes. 22 chromosomes 1. What is a cell? 1.2.The A picture thatofshows 3. normal In the nucleus. are chromosomes one pair that are sex chromosomes. 2. What is a karyotype? 4. Strands of genetic and information is MADE 3. Where is our DNA found? of5. DNA and CONTAINS genes. Sections of DNA that code for our 4. What is a chromosome? eye same colour. 6. characteristics, Different formse.g. of the gene. You 7. mitosisproduces body cells for growth 5. What is a gene? might havecells two produced alleles forfrom eye colour but youand repair. 8. The mitosis or meiosis. TWO are produced and there is ONE cell 9. Adaughter sex (show) cell cells express one. 6. What is an allele? only 10. Specialised cellscells, root hairparent cells, division. The daughter cellse.g. aresex identical to the 7. Name two ways in which cells can divide and describe each of them. neurones etc. are specialised cell. The daughter cellsallare known as cells. DIPLOID as they 8. What is a daughter cell? have two sets of DNA. 9. What is a gamete? Meiosisproduces gametes from diploid 11. Cells that CAN differentiate intocells. otherThe types of 10. Describe what a differentiated cell is. daughter cells are known ascells HAPLOID they 12. Bone marrow stem can do beas used tohave treat cells. Differentiated cells can’t this. But stemhalf cells 13. 15. We Showing can treat the possible diseases chromosome ☺ combinations in the amount of DNA from the parent cell. In humans, leukaemia. The research is on-going to try and treat 11. What is a stem cell? can. Embryos have embryonic stem cells. That’s why 16. Gregor Mendel was a monk. He spent many years If children we are from transferring their parents. cells from one person toSo another, 18. polydactlyhaving more fingers or toes 17. We have chromosomes from our mum dad. we occurs in the testes and ovaries. diseases for spinal injuries etc. 12. How can stem cells bemeiosis used in human treatment? some scientists think we can use them toand treat human studying inheritance using peas. He was trying to it may be rejected or that person will need medication Huntingtonsa disease thatand affects the nervous system have alleles from our dad. Different pairs of 19. Cystic fibrosisaffects cell membranes diseasethat destroy the embryo. 20. If a issues couple has a but history ofwould amum genetic disease, the womans embryo understand why some characteristics would disappear in 13. What are the ethical behind the use of stem cells? all their life alleles can produce different characteristics. stem cells areifeven found in adultsin the bone can be takenLuckily, and to see thethen potential babyinhas alleles for thescreened first generation reappear the next 14. What is variation? Some countries have and banned embryonic stem cell Some alleles are dominantthe characteristic they code which(even can be used to treat didn’t blood show diseases. thatsquare? disease.marrow, generation if their parents this 15. What is a punnet as theythe think this could have been a copies potential forresearch shows whether individual has one or two characteristic). life.allele. 16. What did Gregor Mendelofdo? ☺ The couplethe canconcluded prepare ifthat theirit child mayto have the disease He was due something called(e.g. 17. Some alleles are dominant and some are recessive. What does this mean?may Some alleles are recessivewhere the characteristic save money‘inherited or have counselling to support the couple factors’. We now callthem) these or genes. they code only shows when both chromosomes of the 18. Give examples ofdecide dominant disorders to goA through abortion. lot offor his work was ignored until after his death as pair have that allele. 19. Give examples of May recessive disorders be used to test for other alleles- e.g. eye colour or they didn’t understand. 20.What is screening. Stateor the pros and cons. intelligence sporting ability, aborting babies that are not ‘normal’some may see this as unethical.

eggs ovaries sperm testes sexual

gametes

asexual

fertilisation

peas

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

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

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

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!)

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

Chapter 6- origins of life on Earth 1. Fossils are the remains or traces left of organisms 1. What is a fossil? 5. 6. 4.6 Billion billion ago or 4600 million ago how 2.4.3.5 evolutionbecause we3500 can use themyears to show that once lived.years 2. How can fossils be formed? 3. 7. Radioactive Reduction of dating a species methods to zero. This could happen - organisms Mineral replacementminerals theto ground have that changed over adapted theinyears. 8. Organisms are best the organisms cant evolve fast enough to changes 3. How can we find out howbecause old are?in 9. fossils Where many DIFFERENT species canon die at the replace minerals the hard parts ofpass the skeleton environment survive, reproduce and their 10. Where one species may evolve into another species the environment. 4. Fossils provide evidenceinof…………. same timethis may occur if there is a drastic change such as the bone or shells and this prevents decay. genes. over time. inthe theEarth environment. 5. When do scientists believe was - Mummificationtooformed? cold or too acidic- then decay can’t 6. When do scientists believe lifeoccur. of Earth began? - Moulds and casts- the dead organism may be 7. What does extinction mean? pressed into a soft sediment to form a cast. 8. State what natural selection mean? - Trace fossils- footprints etc. 9. State what mass extinction? 10. What is speciation?

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

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

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

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

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

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

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

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

Biology data analysis questions

plants with all mineral salts grew best

plants with mineral salts but no nitrate grow better than without any mineral salts

((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

rubber plant/fern

Because it can tolerate low levels of light