Cells Banker

1. (a) A student views a cheek cell with a light microscope. The image of the cell is 36 mm wide and the magnification is ×400. What is the actual width of the cell?A 0.09 µmB 9 µmC 90 µmD 900 µm [1]

1. (a) Which equation is correct for an image seen through a microscope?A actual size = image size × magnificationB magnification = actual size ÷ image sizeC image size = actual size × magnificationD image size = magnification ÷ actual size [1]

A student peeled the thin inner layer from an onion scale leaf, stained it with iodine solution and drew one cell as seen with a light microscope.

1. (a) Line XY across the drawing of one cell measures 96 mm. The drawing has a magnification of ×120. Calculate the actual length of the cell in mm. Show your working. [2]
2. (b) Convert your answer to (a) into micrometres (µm). [1]

Paramecium is a single-celled organism found in pond water in Lahore. A specimen is 0.18 mm long. Its image in a field guide is 54 mm long.

1. (a) Calculate the magnification of the image. Show your working. [2]
2. (b) Express the actual length of the Paramecium in µm. [1]

A student in Peshawar wants to look at onion epidermis cells with a light microscope.

1. (a) Describe how the student should prepare a slide of onion epidermis so that cells can be seen clearly. [4]
2. (b) Explain why iodine solution is added. [1]
3. (c) State why the layer of tissue must be very thin. [1]

1. (a) State the formula that links magnification, image size and actual size. [1]
2. (b) A chloroplast is 5 µm long. In a diagram it is drawn 20 mm long. Calculate the magnification of the diagram. [2]

A student draws a root hair cell from a radish seedling at a magnification of ×40. The drawing of the cell, including its hair, is 18 mm long.

1. (a) Calculate the actual length of the root hair cell in mm. [2]
2. (b) State the actual length in µm. [1]

1. (a) A chloroplast-containing alga cell is 25 µm long. In a textbook photograph the same cell is 50 mm long. What is the magnification of the photograph?A ×2B ×200C ×2000D ×20 000 [1]

A photomicrograph shows a sunflower pollen grain at a magnification of ×850. The diameter of the pollen grain on the photograph is 34 mm.

1. (a) Calculate the actual diameter of the pollen grain in µm. Show your working. [2]
2. (b) A student makes a large drawing of the same pollen grain with a diameter of 68 mm. Calculate the magnification of the student's drawing. [2]
3. (c) State why a magnification has no units. [1]

A mosquito larva collected from a water tank is 12 mm long. A student makes a drawing of the larva that is 132 mm long.

1. (a) Calculate the magnification of the drawing. Show your working. [2]
2. (b) Another student got an answer of ×0.09. Explain how you know this answer must be wrong. [1]

A highly magnified image of a rod-shaped bacterium from yoghurt is 60 mm long. The magnification of the image is ×30000.

1. (a) Calculate the actual length of the bacterium in µm. Show your working. [2]
2. (b) How many of these bacteria, placed end to end, would fit across a line 1 mm long? [1]

A student measured the lengths of five cheek cells on a photograph taken at ×1000. The image lengths were: 58 mm, 62 mm, 55 mm, 61 mm, 64 mm.

1. (a) Calculate the mean image length. [1]
2. (b) Use your mean to calculate the actual length of a typical cheek cell in µm. [2]
3. (c) Explain why the student measured five cells rather than one. [1]

A student wants to draw a fish egg that is 0.8 mm in diameter at a magnification of ×50.

1. (a) Calculate how long the student's drawing of the egg should be. [2]
2. (b) State one feature of a good biological drawing that the student should include. [1]

1. (a) A red blood cell has a diameter of 7.5 µm. It is drawn in a revision poster at a magnification of ×6000. What is the diameter of the drawing?A 4.5 mmB 45 mmC 450 mmD 800 mm [1]

A student draws a section through a mango leaf. The actual thickness of the leaf is 0.25 mm. On the drawing the thickness is 75 mm.

1. (a) Calculate the magnification of the drawing. [2]
2. (b) On the same drawing one palisade mesophyll cell is 21 mm long. Use your answer to (a) to calculate the actual length of this cell in µm. [2]
3. (c) The student's calculated value is larger than the value given in a textbook. Suggest one reason, other than a calculation error, for this difference. [1]

Two cells were photographed. Cell P (a cheek cell) has an image 45 mm long at ×1500. Cell Q (a plant cell) has an image 30 mm long at ×600.

1. (a) Calculate the actual length of each cell in µm. [3]
2. (b) A student says that cell P is bigger because its image is bigger. Use your answers to explain why the student is wrong. [2]

A human egg cell has a diameter of about 70 µm. A photograph shows an egg cell with an image diameter of 42 mm.

1. (a) Calculate the magnification of the photograph. [2]
2. (b) The same photograph is enlarged on a classroom screen so that the image of the cell becomes 210 mm long. Calculate the new magnification. [2]
3. (c) Explain whether enlarging the photograph lets you see more detail of the cell. [1]

1. (a) Which structure is found in both plant cells and animal cells?A cell wallB chloroplastC large permanent vacuoleD ribosome [1]

1. (a) Copy and complete the table by writing 'present' or 'absent' in each space.Structure | palisade mesophyll cell | liver cellcell wall | ? | ?chloroplasts | ? | ?nucleus | ? | ?cell membrane | ? | ? [4]
2. (b) State the function of the cell membrane. [1]

1. (a) State the main substance from which a plant cell wall is made. [1]
2. (b) Explain the difference between the cell wall and the cell membrane in how substances pass through. [2]
3. (c) State one function of the cell wall. [1]

1. (a) A cell from a leaf is treated so that its mitochondria stop working. Which process in the cell stops first?A aerobic respirationB photosynthesisC diffusion of carbon dioxideD protein synthesis on ribosomes [1]

Lactobacillus is a bacterium used to make yoghurt (dahi). Its cell has a cell wall, cell membrane, cytoplasm, ribosomes, a loop of circular DNA and small plasmids.

1. (a) State two structures that are found in this bacterial cell but are not found in a human cheek cell. [2]
2. (b) Describe how the genetic material of a bacterium differs from that of a plant cell. [2]
3. (c) Name the structures in the bacterium where proteins are made. [1]

1. (a) State the function of the nucleus. [1]
2. (b) State the function of ribosomes. [1]
3. (c) Describe the function of the large permanent vacuole in a plant cell. [2]

Cell R was found in a water sample from a pond in Murree. It has a nucleus, a cell wall, a cell membrane, several chloroplasts and a large vacuole full of cell sap.

1. (a) Identify whether cell R is a plant cell, an animal cell or a bacterial cell. Give two reasons from the description. [3]
2. (b) Cell S has a nucleus, cell membrane and many mitochondria but no cell wall. Name the type of cell. [1]

1. (a) Suggest why sperm cells have many mitochondria in the middle region. [2]
2. (b) Root hair cells do not have chloroplasts. Explain why. [2]
3. (c) Suggest why cells in the pancreas that make digestive enzymes have many ribosomes. [1]

1. (a) State where in the cell the chemical reactions of aerobic respiration take place. [1]
2. (b) Muscle cells in a sprinter's legs contain more mitochondria than skin cells. Explain why. [2]
3. (c) Name the part of the cell where most chemical reactions of the cell take place, and state what it contains. [2]

1. (a) Which list is in order of increasing level of organisation?A cell → organ → tissue → organ systemB cell → tissue → organ → organ systemC tissue → cell → organ → organismD organ → tissue → organ system → organism [1]

1. (a) For each of the following, state whether it is a cell, a tissue, an organ or an organ system: (i) the heart (ii) xylem (iii) a neurone (iv) the stomach, intestines and liver working together. [4]
2. (b) Define the term organ. [1]

1. (a) Copy and complete the table to show one feature of each cell and how it helps the cell's function.Cell | function | feature | how the feature helpsciliated cell | ? | ? | ?red blood cell | ? | ? | ? [4]
2. (b) State the meaning of the term tissue. [1]

1. (a) Explain how the shape of a root hair cell helps it to absorb water and mineral ions. [2]
2. (b) Explain how a palisade mesophyll cell is adapted for photosynthesis. [2]
3. (c) A motor neurone can be over 1 m long. Suggest how this length is an advantage. [1]