Cell StructureAQA GCSE Biology: Flashcards

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What is the function of the cell membrane?

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What is the function of the cell membrane?: The cell membrane controls what enters and leaves the cell. It is a partially permeable membrane that surrounds the cytoplasm in all cells.
Define the cell wall and state which cell types have one.: The cell wall is a rigid structure outside the cell membrane that provides support and protection. It is found in plant cells and bacterial cells, but not in animal cells.
What is the function of the nucleus?: The nucleus controls cell activities and contains the genetic material (DNA). It regulates protein synthesis and cell division.
Describe the function of mitochondria.: Mitochondria release energy from glucose during aerobic respiration. They are the site of energy production in cells.
What is the function of ribosomes?: Ribosomes are the site of protein synthesis. They read messenger RNA (mRNA) and build proteins according to the genetic code.
Name two structures found in plant cells but not in animal cells.: Chloroplasts and cell wall. Vacuoles are also larger in plant cells than animal cells.
What is the function of chloroplasts?: Chloroplasts are the site of photosynthesis. They contain chlorophyll and convert light energy into chemical energy in glucose.
Describe the function of the vacuole in plant cells.: The vacuole stores water, ions, and nutrients. It maintains cell turgor and helps keep the plant rigid.
Explain the key difference between prokaryotic and eukaryotic cells.: Prokaryotic cells do not have a membrane-bound nucleus; their DNA is in a nucleoid region. Eukaryotic cells have a true nucleus enclosed by a nuclear membrane. Prokaryotic cells are smaller and simpler (bacteria and archaea); eukaryotic cells are larger and more complex (animals, plants, fungi).
Name three structures found in a bacterial cell.: Nucleus (nucleoid region), ribosomes, cell membrane, cell wall, cytoplasm, plasmids, flagella, pili, and capsule.
What is a plasmid and what is its function in bacteria?: A plasmid is a small, circular loop of DNA found in bacterial cells. It carries additional genes, often for antibiotic resistance or survival advantages.
Explain why plant cells have cell walls but animal cells do not.: Plant cells need rigid cell walls for structural support because plants cannot move. Animal cells have only a flexible cell membrane because animals need flexibility for movement.
What is the formula for calculating magnification?: Magnification = image size ÷ actual size. All measurements must be in the same units.
Convert 5 micrometres (μm) into nanometres (nm).: 5 μm = 5,000 nm. One micrometre equals 1,000 nanometres.
State two advantages of electron microscopes over light microscopes.: Electron microscopes have much higher resolution, allowing greater magnification. They can reveal fine details of sub-cellular structures that light microscopes cannot distinguish.