AQA GCSE Biology Paper 2 – Practice Questions with Model Answers – Secondary School, Exams of Biology

Download AQA GCSE Biology Paper 2 – Practice Questions with Model Answers – Secondary School and more Exams Biology in PDF only on Docsity!

• AQA GCSE Biology paper

"An echidna can dilate and constrict blood vessels in its skin. Explain how the dilation of blood vessels in the skin can help to decrease body temperature. - CORRECT ANSWER -more blood flow near surface

• so more heat is lost from the blood
• cools blood which cools the body" "The athlete's energy intake each day from food was 20 000 kJ. Evaporation of 1cm^3 sweat requires 2.5 kJ of energy. 40% of the athlete's daily energy intake was used to evaporate sweat. Calculate the volume of sweat the athlete lost each day. Give your answers in dm^ 1dm^3 = 1000 cm^3 - CORRECT ANSWER 20 000 x 40 / 100 x 2.5 = 3200 cm^ 3200 / 1000 = 3.2 dm^ Volume of sweat lost in one day = 3.2 dm^3" "Suggest why the athlete was advised to take salt tablets every day - CORRECT ANSWER to replace ions lost in sweat." "Students investigated the response of plant shoots to one-sided light. Suggest two control variables the students should have used in their investigation. - CORRECT ANSWER same volume of water same type of plant" "Describe how experiment B and experiment C acted as controls for the investigation - CORRECT ANSWER B shows response is due to light C shows response is due to one-sided light" "Give two ways that a person can reduce the chance of developing type 2 diabetes - CORRECT ANSWER more exercise eat a low carbohydrate diet" "Name three harmful substances that could cause water pollution Do not refer to plastic or to litter in your answer - CORRECT ANSWER Fertiliser Sewage herbicide" "Describe how substances that pollute air and water could be harmful to humans and other living organisms - CORRECT ANSWER Air pollution
• Sulfur dioxide causes damage to leaves so less photosynthesis take place. -damage to roots or alters ions in soil so less protein is made.
• damage to lungs which can lead to breathing difficulties. -Carbon monoxide combines with haemoglobin so less oxygen is carried. -Particulates blocks light leading to less photosynthesis taking place and less glucose being made

"A scientist made a hypothesis: 'Light causes auxin to move from the side of the shoot nearest to the light to the side furthest from the light' Describe the evidence from Figure 14 which supports the hypothesis. - CORRECT ANSWER in F there is more auxin in the side furthest from the light in G there is the same mass of auxin in each side in F auxin can move through the shoot but in G the glass prevents this" "Another scientist made a different hypothesis: 'Light causes the breakdown of auxin' Give the evidence from Figure 14 that shows that auxin is not broken down by light - CORRECT ANSWER all four block approximately have the same mass of auxin" "One week later the scientist repeated the test and counted 14 cells on the 0.2mm x 0.2mm counting grid. Calculate the number of algal cells in 1.0 mm^3 of undiluted pond water. Use the scientist's second count of 14 cells. - CORRECT ANSWER volume of sample in mm3 0.004 (0.2 x 0.2 x 0.1) number of cells in 1 mm3 diluted pond water 14 ÷ 0. 3 500 number of cells in 1 mm3 undiluted pond water 3 500 × 4 14 000 or 1.4 × 104" "Suggest why the scientist diluted the pond water before placing it on the special slide - CORRECT ANSWER to make it easier to count" Complete table 1 to compare sexual reproduction with asexual reproduction. Write a tick in the box if the statement is true. The first row has been completed for you. - CORRECT ANSWER Sexual reproduction -cell division occurs -fertilisation occurs asexual reproduction -cell division occurs -genes are passed on from parent to offspring -offspring are genetically identical to each other" "Students investigated the population of earthworms in the soil in two different areas. -Area A: a grass lawn -Area B: a farmer's field Chemical X can be mixed with water and poured onto the soil. The mixture beings earthworms to the surface of the soil but does not harm the earthworms.

Plan an investigation using chemical X to compare the number of earthworms per m^ in areas A and B. - CORRECT ANSWER -Same concentration of chemical applied to the soil -Same volume of chemical applied to the soil -Same size of area sampled e.g. 1m^2 or 0.25m^ -Use of quadrat -Same time between application and collecting worms -Same time allowed for collecting worm after application -Each sample area selected randomly -Method achieving randomness e.g. random coordinates -Count worms in each of the areas A and B -At least 5 repeats in each of the areas A and B -Calculate mean -Compare means" "Explain the effect of a high concentration of insulin has on blood glucose concentration.

• CORRECT ANSWER Effect: lowered Explanation: Glucose is taken in by cells" "Table 2 shows: -the results of the blood test -the mean results for people who do not have diabetes Type 2 diabetes occurs when body cells have a reduced response to insulin. Give two ways the results of the blood test show that person C might have Type 2 diabetes. - CORRECT ANSWER high concentration of insulin high glucose" "A student repeated the scientist's method. The student used a thin coverslip over the diluted pond water instead of the thick coverslip. The liquid pulled the thin coverslip downwards slightly Explain how the use of the thin coverslip would affect the results for the cell count - CORRECT ANSWER Smaller volume so fewer cells" "Explain why the decrease in body temperature is an advantage to the echidna during hibernation - CORRECT ANSWER -less energy being transferred maintaining body temperature -so more energy available for processes vital for life." "During hibernation the echidna wakes up several times Each time the echidna wakes up it becomes active and its body temperature increases over 30 degrees