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The cell wall is a rigid structure that surrounds cells in plants, algae and fungi. It’s made mainly of the carbohydrate cellulose in plant and algae cells. In fungi, the cell wall is made of chitin. Its primary function is to support cells and prevent them from changing shape.
2.1 Cell Structure OCR ExamBuilder. 1(a). Plant and animal cells have different structural features. Name two features of plant cells that are not features of animal cells. Name one structure present in animal cells that is not present in plant cells. The cytoskeleton in cells consists of microtubules and microfilaments. [2]
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The diagram shows part of an epithelial cell from an insect’s gut. This cell is adapted for the three functions listed below. Use the diagram to explain how this cell
Dec 5, 2023 · Structural support is provided by the polysaccharide cellulose in plants, and peptidoglycan in most bacterial cells. Narrow threads of cytoplasm (surrounded by a cell membrane) called plasmodesmata connect the cytoplasm of neighbouring plant cells.
TEMs produce a high resolution image to see internal structure of organelles. They can only be used on thin specimens. Scanning electron microscopes (SEMs) Scans a beam of electrons over the specimen that knocks off electrons that are gathered in a cathode ray tube to form an image.
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Describe how a transmission electron microscope (TEM) works. 1. Pass a high energy. beam of electrons. a thin slice of specimen. 2. More dense. structures appear. darker. through. since they absorb more electrons. 3. Focus image onto fluorescent screen or photographic plate using magnetic lenses.
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DNA is ‘free’ in cytoplasm, no organelles e.g. bacteria & archaea. State the relationship between a system and specialised cells. Specialised cells → tissues that perform specific function → organs made of several tissue types → organ systems. Describe the structure and function of the cell-surface membrane. ‘Fluid mosaic’ phospholipid bilayer.
