Cell structure

• What is a cell?

  The smallest unit of life that can live on its own. Cells make up all living organisms and their tissues
• What are the differences between eukaryotic and prokaryotic cells?

  Eukaryotic cells are much larger than prokaryotic cells

  Eukaryotic cells contain membrane-bound organelles, while prokaryotic cells do not.

  Eukaryotic cells keep their DNA in the form of chromosomes within a nucleus, whilst prokaryotic cells have their DNA loose in the cell
• For animal, plant and bacterial cells, state whether they are either eukaryotic or prokaryotic

  Animal and plant cells are eukaryotic

  Bacterial cells are prokaryotic
• Name 5 sub-cellular structures (organelles) that are found in both animal and plant cells.

  Cell membrane, ribosomes, nucleus, mitochondria and cytoplasm
• What is the cell membrane and what is its role?

  A protective barrier around the outside of the cell. It controls which substances can pass in and out of the cell
• What is cytoplasm and what is its role?

  A jelly-like liquid that fills the cell. It allows substances to dissolve, and chemical reactions to take place
• What is the role of the nucleus?

  It contains genetic material (DNA) of the cell, and so controls what the cell does
• What is the role of the mitochondria?


  They carry out aerobic respiration, so provide energy (in the form of ATP) for the cell to use in chemical reactions.
• What is the role of ribosomes?

  They are the site of protein synthesis (where proteins are made).
• Name three sub-cellular structures (organelles) that are found in plant cells but not animal cells.


  Cell wall, permanent vacuole, chloroplast
• In plants, what is the cell wall made of?

  Cellulose
• What is the role of the plant cell wall?


  It provides strength and structure to the plant cell, preventing it from bursting or shrinking when water enters/leaves the cell via osmosis.
• What does the permanent vacuole contain?


  Cell sap (a solution of salts, sugars and amino acids).
• What is the role of the permanent vacuole?

  It supports the cell, maintaining its turgidity (shape)
• What is the role of chloroplasts?

  They are the sight of photosynthesis, so make glucose for the cell
• What is chlorophyll?


  A green pigment within chloroplasts that absorbs sunlight for photosynthesis.
• Name 7 sub-cellular structures (organelles) that are found in bacterial cells.

  Cell wall, cell membrane, cytoplasm, circular strand of DNA (nucleoid),plasmid, ribosome
• What are plasmids, and what are their role?


  Small, circular loops of DNA that are separate to the main DNA. They contain 'extra genes' that are sometimes useful to the bacteria, such as antibiotic resistance
• What is the prokaryotic cell wall composed of?

  Peptidoglycan