Cell Structure and Organisation: Biology 0610 (Cambridge O Level / IGCSE)
Syllabus 2.1, 2.2 · Strand 2 Organisation of the organism
- Questions
- 10
- Total marks
- 36
- Tier mix
- 6 Core · 4 Extended
0 of 10 questions completed
Syllabus coverage
- 2.1 8 questions completed
- 2.2 2 questions completed
Cells are the basic building blocks of every living organism, and this topic (syllabus 2.1 and 2.2) starts by comparing the three types you must know. Plant and animal cells share a nucleus, cytoplasm, cell membrane, ribosomes and mitochondria, while plant cells add a cellulose cell wall, chloroplasts and a permanent vacuole. Bacterial cells are different again, having a cell wall, a loop of circular DNA and plasmids but no nucleus. Being able to identify each structure in a diagram and state its function, from the nucleus controlling activities to mitochondria releasing energy in respiration, is a common exam requirement.
Cells become specialised to carry out particular jobs, and their shape reflects their function. Root hair cells have a large surface area for absorbing water, red blood cells carry oxygen, ciliated cells sweep mucus, and neurones conduct electrical impulses. These cells are organised into tissues, organs, organ systems and finally the whole organism. Because cells are so small, biologists measure them under a microscope and calculate size using magnification = image size ÷ actual size, rearranging the formula as needed and, for Extended candidates, converting between millimetres and micrometres.
The exam-style questions below are original, written to match this objective, each with a full worked solution so you can check your method step by step.
Question 1
A microbiologist takes a single bacterium from a laboratory culture and examines it under a powerful electron microscope. The image shows a cell surrounded by a cell wall and a cell membrane, with cytoplasm containing ribosomes, one large loop of circular DNA and several small plasmids.
Which structure, present in both plant and animal cells, is missing from this bacterial cell?
Question 2
For a school open day, three students each build a large model of a different specialised cell: a ciliated cell from the lining of the trachea, a root hair cell from a young plant's root, and a palisade mesophyll cell from a leaf.
(a) State the main function of each of these three specialised cells.
(i) ciliated cell [1]
(ii) root hair cell [1]
(iii) palisade mesophyll cell [1]
(b) Describe how the shape of the root hair cell is related to its function. [2]
Question 3
A student uses a light microscope fitted with a camera to take photomicrographs of two different specialised cells: a root hair cell from a growing root tip, and a human sperm cell.
(a) The actual length of the root hair cell is 0.8 mm. In its photomicrograph, this cell has been magnified ×60. Calculate the length of the root hair cell as it appears in the photomicrograph, giving your answer in mm. [2]
(b) In a second photomicrograph, the sperm cell appears 9 mm long. The actual length of this sperm cell is 0.06 mm. Calculate the magnification used to produce this photomicrograph. [2]
(c) Convert the actual length of the root hair cell, 0.8 mm, into micrometres (μm). [1]
Question 4
A student describes part of the human stomach wall as follows: "It is built from muscle tissue and glandular tissue working together, and its role is to churn food and mix it with digestive juices."
Which level of biological organisation is being described here?
Question 5
A food-safety officer takes a swab from each of three different surfaces in a kitchen and examines a single cell from each sample under a high-powered microscope. The structures visible in each cell are recorded below.
Sample 1: cell wall, cell membrane, cytoplasm, a large permanent vacuole, chloroplasts, a nucleus
Sample 2: cell wall, cell membrane, cytoplasm, ribosomes, one loop of circular DNA, several plasmids, no nucleus
Sample 3: cell membrane, cytoplasm, mitochondria, a nucleus, no cell wall
(a) Identify whether each sample is a plant cell, an animal cell or a bacterial cell. [3]
(b) Sample 2 lacks a structure that is present in both sample 1 and sample 3. Name this structure and state its function. [2]
(c) Name one structure present in sample 1 but absent from both samples 2 and 3, and give its function. [2]
Question 6
A biology teacher shows the class an animation of a single, sausage-shaped structure inside a cell. As the animation plays, a label explains that this structure is where most of the energy needed for the cell's activities is released, during aerobic respiration.
Which structure is being shown in the animation?
Question 7
A biology class studies two prepared microscope slides: one showing a red blood cell from a blood smear, and one showing a neurone (nerve cell) from a section of spinal cord.
(a) State the main function of each of these cells.
(i) red blood cell [1]
(ii) neurone [1]
(b) Describe two ways in which the structure of a red blood cell is related to its function. [2]
(c) Describe one way in which the structure of a neurone is related to its function. [2]
Question 8
A cell diagram is labelled with a thin layer that forms the outer boundary of the cytoplasm in every plant, animal and bacterial cell. A caption beside the label states that this structure controls which substances can enter and leave the cell.
Which structure is being described?
Question 9
A student examines cells from a moss leaf, first with a light microscope and then, for one chloroplast within a cell, with an electron microscope.
(a) In the light micrograph, one moss leaf cell appears 3.6 mm long. This micrograph was taken at a magnification of ×120. Calculate the actual length of the cell, giving your answer in mm. [2]
(b) The actual diameter of a chloroplast inside this cell is 5 μm. Convert this length into mm. [1]
(c) In the electron micrograph, the same chloroplast appears 0.4 mm in diameter. Using the actual diameter of the chloroplast, calculate the magnification of this electron micrograph. [2]
Question 10
A food scientist studies a species of bacterium used to make yoghurt. A diagram of a single cell shows a cell wall, a cell membrane, cytoplasm containing ribosomes, one large loop of circular DNA, and several small plasmids.
Describe the function of each of the following structures in this bacterial cell.
(a) cell wall [1]
(b) circular DNA (bacterial chromosome) [2]
(c) plasmid [1]