Sec 3 Biology Cell Structure & Organisation topical questions

State the function of the cellulose cell wall in a plant cell.

Name three structures that a typical plant cell has but a typical animal cell does not.

Match each organelle to its function: mitochondrion, ribosome, chloroplast. Functions: absorbing light for photosynthesis; releasing energy from glucose; assembling proteins.

Define a tissue and name one tissue found in a human.

Name the organelle that carries out each of these jobs in a cell: releasing energy from glucose, assembling proteins, and packaging enzymes for secretion.

Explain why muscle cells contain very large numbers of mitochondria.

A chloroplast appears 30 mm long in a micrograph. Its actual length is 15 µm. Calculate the magnification of the micrograph.

Explain how three structural features of a mature red blood cell adapt it to transporting oxygen.

A cell is drawn 25 mm wide at a magnification of ×400. Calculate the cell’s real width in micrometres (µm).

A micrograph carries a scale bar labelled 5 µm that measures 15 mm on the print. (a) Calculate the magnification of the print. (b) A mitochondrion in the same micrograph appears 36 mm long. Calculate its actual length in µm.

Explain why a root hair cell contains no chloroplasts even though it is a plant cell.

Three cells are described. Cell P: cellulose wall, many chloroplasts, one large vacuole. Cell Q: flexible membrane only, no nucleus, biconcave shape. Cell R: membrane only, visible nucleus, many mitochondria. Identify a likely cell type for each, using one listed feature to justify each identification.

A root hair cell’s hair is modelled as a cylinder of length 800 µm and diameter 20 µm. The cell body is a box measuring 100 µm × 50 µm × 50 µm. Calculate the extra surface area the hair adds, and the percentage increase in the cell’s exchanging surface. (Take π = 3.14.)

An electron micrograph of a cell from the pancreas shows an extensive endoplasmic reticulum, huge numbers of ribosomes and a very prominent Golgi body. Explain what these structures suggest about the cell’s activity.

Explain why division of labour among specialised cells, tissues and organs makes a multicellular organism efficient. Use the human digestive system as an example.

Three cells are photographed. Cell P appears 16 mm wide (actual 40 µm), cell Q appears 9 mm wide (actual 30 µm) and cell R appears 14 mm wide (actual 7 µm). Calculate the magnification of each photograph and state which cell is really the smallest.

A student must find the actual diameter of an onion epidermal cell using a light microscope. Plan how she should carry out the investigation, including why staining is used and how magnification is applied to the measurement.

Two cube-shaped cells are compared. Cell A has sides of 20 µm; cell B has sides of 40 µm. (a) Calculate the surface area, volume and surface-area-to-volume ratio of each cell. (b) Explain why the smaller cell exchanges substances with its surroundings faster.