Year 11 Paper 2: Genetics, Evolution and Ecology
Covers genetics and inheritance, evolution and natural selection, ecosystems and material cycles, cell structure and transport, cell division and stem cells, and photosynthesis.
Year 11 here means a typical teaching order, not a syllabus rule. No exam board defines what belongs to Year 11, and schools sequence the course differently. Check it against your own scheme of work before using it to decide what a class has covered.
Questions
Question 1 [2 marks]
Cell Structure and Transport
A student is studying an animal cell under a microscope.
State the function of the mitochondria and state the function of the ribosomes in the cell.
Question 2 [2 marks]
Cell Division and Stem Cells
State what is meant by differentiation, and state one example of a specialised cell produced by differentiation.
Question 3 [2 marks]
Cell Structure and Transport
State the function of the nucleus in a cell, and state the function of the cell membrane.
Question 4 [3 marks]
Evolution and Natural Selection
Selective breeding is a process used by humans to breed animals or plants with desired characteristics.
State what is meant by selective breeding, and give one example of a characteristic farmers might select for in cattle.
Question 5 [3 marks]
Genetics and Inheritance
Cystic fibrosis is caused by a recessive allele.
Describe what is meant by a dominant allele and a recessive allele, using cystic fibrosis as an example.
Question 6 [3 marks]
Ecosystems and Material Cycles
A student wants to estimate the population of daisies in a field.
Describe how the student could use quadrats to estimate the total number of daisies in the field.
Question 7 [3 marks]
Genetics and Inheritance
Describe how DNA can be extracted from fruit cells in a simple school practical, including the general purpose of adding detergent to the mixture.
Question 8 [3 marks]
Photosynthesis
Describe the role of stomata and guard cells in gas exchange in a leaf.
Question 9 [3 marks]
Cell Structure and Transport
A student compares a plant cell and an animal cell using a light microscope.
State three structures that can be found in a plant cell but are not found in an animal cell.
Question 10 [4 marks]
Photosynthesis
A student counted bubbles of oxygen released by pondweed placed at different distances from a lamp.
At 10 cm from the lamp, 45 bubbles were counted in 3 minutes.
Calculate the mean rate of oxygen production. Give an appropriate unit with your answer.
Question 11 [4 marks]
Ecosystems and Material Cycles
A student estimates the population of snails in a garden using the mark-release-recapture method. On the first day, 40 snails are caught, marked, and released. The next day, 50 snails are caught, of which 8 are found to be marked.
Calculate an estimate of the total population of snails in the garden, using population estimate = (number marked in first sample x total number in second sample) / number of marked individuals recaptured.
Question 12 [4 marks]
Cell Division and Stem Cells
A human body cell contains 46 chromosomes.
Calculate the number of chromosomes in a human gamete (sex cell) produced by meiosis, and calculate the number of chromosomes that would be present in a zygote formed when two gametes fuse at fertilisation.
Question 13 [4 marks]
Genetics and Inheritance
Both parents are heterozygous carriers of the cystic fibrosis allele (Ff), where f is the recessive cystic fibrosis allele.
Use a genetic diagram (Punnett square) to calculate the probability that a child of these two parents has cystic fibrosis (ff). Give your answer as a percentage.
Question 14 [5 marks]
Cell Structure and Transport
In an osmosis investigation, a potato chip had a mass of 4.20 g before being placed in a concentrated sugar solution for 24 hours. After 24 hours, its mass was 3.57 g.
Calculate the percentage change in mass of the potato chip, and state whether this change indicates the potato chip lost or gained water.
Question 15 [5 marks]
Cell Division and Stem Cells
Describe the three main stages of the cell cycle that a cell goes through before and during division.
Question 16 [5 marks]
Cell Structure and Transport
A student sets the eyepiece lens of a microscope to a magnification of x10 and the objective lens to a magnification of x40.
Calculate the total magnification produced by the microscope. The student then measures a cell using this microscope and finds its magnified image is 8000 micrometres wide. Calculate the actual width of the cell in micrometres.
Question 17 [5 marks]
Ecosystems and Material Cycles
Describe the processes involved in the water cycle that result in fresh water falling as rain on land.
Model solutions
| Question 1[2 marks] | |
|---|---|
| Answer or working | Marks |
| mitochondria: site of (aerobic) respiration, releasing energy | B1 |
| ribosomes: site of protein synthesis | B1 |
| Final answer: Mitochondria: aerobic respiration (releases energy); ribosomes: protein synthesis | |
| Question 2[2 marks] | |
|---|---|
| Answer or working | Marks |
| differentiation is the process by which a cell changes to become specialised for its function | B1 |
| a valid example, such as a nerve cell, a muscle cell or a red blood cell | B1 |
| Final answer: Differentiation is a cell becoming specialised for its function, e.g. becoming a nerve cell or a muscle cell | |
| Question 3[2 marks] | |
|---|---|
| Answer or working | Marks |
| the nucleus contains the genetic material (DNA) and controls the cell's activities | B1 |
| the cell membrane controls what substances enter and leave the cell | B1 |
| Final answer: Nucleus: contains DNA and controls the cell's activities; cell membrane: controls substances entering and leaving the cell | |
| Question 4[3 marks] | |
|---|---|
| Answer or working | Marks |
| selective breeding being the process by which humans choose organisms with particular desired characteristics to breed together over many generations | B1 |
| a valid example, such as high milk yield, resistance to disease, or docile temperament | B1 |
| only organisms showing the desired characteristic being selected as parents for the next generation | B1 |
| Final answer: Selective breeding is choosing organisms with desired characteristics (e.g. high milk yield in cattle) to breed together over generations so more offspring show that characteristic | |
| Question 5[3 marks] | |
|---|---|
| Answer or working | Marks |
| a dominant allele is expressed in the phenotype even if only one copy is present | B1 |
| a recessive allele is only expressed if two copies are present, with no dominant allele present | B1 |
| a person with cystic fibrosis must have inherited the recessive allele from both parents | B1 |
| Final answer: A dominant allele shows in the phenotype with just one copy; a recessive allele (like the cystic fibrosis allele) only shows if both copies are recessive | |
| Question 6[3 marks] | |
|---|---|
| Answer or working | Marks |
| placing a number of quadrats randomly across the field | B1 |
| counting the number of daisies in each quadrat and finding the mean number per quadrat | B1 |
| multiplying the mean number per quadrat by the total area of the field divided by the area of one quadrat, to estimate the total population | B1 |
| Final answer: Count daisies in several randomly placed quadrats, find the mean per quadrat, then scale up by the ratio of the field's area to one quadrat's area | |
| Question 7[3 marks] | |
|---|---|
| Answer or working | Marks |
| the fruit is broken down/mashed, then mixed with a salt solution and a detergent (e.g. washing-up liquid) | B1 |
| the detergent breaks down (disrupts) the cell membranes, releasing the DNA from inside the cells | B1 |
| cold ethanol (alcohol) is then carefully added/layered on top, causing the DNA to become insoluble and visible, so it can be collected | B1 |
| Final answer: Fruit is mashed with salt solution and detergent, which breaks down cell membranes to release DNA; cold ethanol is then added, making the DNA visible so it can be collected | |
| Question 8[3 marks] | |
|---|---|
| Answer or working | Marks |
| stomata are small pores/openings, mostly on the underside of a leaf, that allow gases to diffuse in and out | B1 |
| carbon dioxide diffuses in through the stomata for photosynthesis, and oxygen (and excess water vapour) diffuses out | B1 |
| guard cells surround each stoma and can change shape to open or close it, controlling gas exchange (and water loss) | B1 |
| Final answer: Stomata are pores that let carbon dioxide diffuse in and oxygen/water vapour diffuse out; guard cells around each stoma open or close it to control this exchange | |
| Question 9[3 marks] | |
|---|---|
| Answer or working | Marks |
| a cell wall (made of cellulose) | B1 |
| chloroplasts | B1 |
| a large permanent vacuole | B1 |
| Final answer: Cell wall, chloroplasts, and a large permanent vacuole | |
| Question 10[4 marks] | |
|---|---|
| Answer or working | Marks |
| using rate = number of bubbles / time | M1 |
| substituting 45 / 3 | M1 |
| 15 | A1 |
| the correct unit, bubbles per minute | B1independent |
| Final answer: 15 bubbles per minute | |
| Question 11[4 marks] | |
|---|---|
| Answer or working | Marks |
| using the given formula, population estimate = (number marked in first sample x total in second sample) / number recaptured marked | M1 |
| substituting (40 x 50) / 8 | M1 |
| calculating 40 x 50 = 2000 | M1 |
| 250 snails | A1 |
| Final answer: An estimated population of 250 snails | |
| Question 12[4 marks] | |
|---|---|
| Answer or working | Marks |
| recognising gametes contain half the number of chromosomes of a body cell (meiosis halves the chromosome number) | M1 |
| 23 chromosomes in a gamete | A1 |
| recognising fertilisation combines one gamete from each parent | M1 |
| 46 chromosomes in the zygote | A1 |
| Final answer: A gamete contains 23 chromosomes; the zygote formed at fertilisation contains 46 chromosomes | |
| Question 13[4 marks] | |
|---|---|
| Answer or working | Marks |
| a correctly completed Punnett square showing genotypes FF, Ff, Ff, ff | M1 |
| identifying 1 out of 4 offspring as ff | M1 |
| converting the ratio to a percentage | M1 |
| 25% | A1 |
| Question 14[5 marks] | |
|---|---|
| Answer or working | Marks |
| finding the change in mass = 3.57 - 4.20 = -0.63 g | M1 |
| using percentage change = (change in mass / original mass) x 100 | M1 |
| substituting (-0.63 / 4.20) x 100 | M1 |
| a percentage change of -15% (a 15% decrease) | A1 |
| stating the potato chip lost water, because its mass decreased | B1independent |
| Final answer: The mass decreased by 15% (a change of -15%), showing the potato chip lost water | |
| Question 15[5 marks] | |
|---|---|
| Answer or working | Marks |
| a growth stage (interphase), where the cell grows and increases the number of sub-cellular structures such as mitochondria and ribosomes | B1 |
| DNA replication, where the genetic material is duplicated to form two copies of each chromosome | B1 |
| mitosis, where the chromosomes are separated and the nucleus divides to form two genetically identical nuclei | B1 |
| division of the cytoplasm and cell membranes, forming two identical daughter cells | B1 |
| the daughter cells produced being genetically identical to the parent cell and to each other | B1 |
| Final answer: The cell grows and replicates its DNA and organelles, chromosomes are separated during mitosis into two genetically identical nuclei, then the cytoplasm divides to form two identical daughter cells | |
| Question 16[5 marks] | |
|---|---|
| Answer or working | Marks |
| total magnification = eyepiece magnification x objective magnification | M1 |
| total magnification = 10 x 40 = x400 | A1 |
| using actual size = image size / magnification | M1 |
| substituting 8000 / 400 | M1 |
| actual width = 20 micrometres | A1 |
| Final answer: Total magnification = x400; actual width of the cell = 20 micrometres | |
| Question 17[5 marks] | |
|---|---|
| Answer or working | Marks |
| the Sun heating water in oceans, rivers and lakes, causing evaporation of water into water vapour | B1 |
| plants also losing water vapour to the atmosphere through transpiration | B1 |
| water vapour rising and cooling, and condensing to form clouds (tiny droplets of water) | B1 |
| water droplets in clouds joining together and becoming heavier | B1 |
| the droplets falling as precipitation (rain) once heavy enough | B1 |
| Final answer: Water evaporates (and transpires) from oceans, land and plants; the vapour rises, cools and condenses into clouds, and eventually falls as precipitation (rain) | |