cells or wtv

• Eukaryotic cells


  Cells that contain their genetic material enclosed in a nucleus
• Eukaryotic cells


  • Contain a nucleus
  • Contain a cell membrane
  • Contain cytoplasm
• Prokaryotic cells


  Cells where the genetic material is not enclosed in a nucleus
• Prokaryotic cells


  • Do not have a nucleus
  • Have a cell membrane
  • Have a cell wall
  • Contain cytoplasm
  • May have plasmids
• Prokaryotic cells


  Are much smaller than eukaryotic cells
• Eukaryotic cells include animal and plant cells
• Prokaryotic cells include bacterial cells
• You will find plenty of questions on eukaryotic and prokaryotic cells in the revision workbook
• Meter


  The base unit of measurement in science
• Sizes in biology


  • Often much smaller than a meter
• Centi


  One hundredth of a meter
• 1 cm is 1 * 10^-2 m
• Milli


  One thousandth of a meter
• 1 mm is 1 * 10^-3 m
• Micro


  One millionth of a meter
• 1 micrometer is 1 * 10^-6 m
• Typical human cell size

  • 10-20 micrometers
• Nano


  One billionth of a meter
• 1 nanometer is 1 * 10^-9 m
• Hemoglobin molecule size


  • 5 nanometers in diameter
• Plenty of questions on cell sizes in the revision workbook
• Order of magnitude


  A way to compare the approximate size of different objects
• Objects of the same order of magnitude

  • Apple and orange
• Pineapple and lemon


  Pineapple is one order of magnitude larger than lemon
• Dog and woodlouse


  Dog is two orders of magnitude longer than woodlouse
• Order of magnitude


  Every order of magnitude is ten times greater than the one before
• Counting zeros


  Tells you the order of magnitude
• Order of magnitude


  • 10 times = 1 order of magnitude

  100 times = 2 orders of magnitude

  1000 times = 3 orders of magnitude
• Calculating order of magnitude


  Find how many times larger one object is than another

  2. Count the number of zeros to determine the order of magnitude
• A fox is around 40 cm long, a tick on the fox is around 0.4 cm long
• Fox length


  100 times longer than the tick
• The fox is two orders of magnitude longer than the tick
• What are cells considered in biological terms?

  The basic building blocks of life
• What is the smallest unit of life that can replicate independently?

  A cell
• How do animal and plant cells differ from bacterial cells in terms of cell type?

  Animal and plant cells are eukaryotic, while bacterial cells are prokaryotic
• What is the total estimated number of cells in an adult human?

  Over 40 trillion cells
• What are the main components of a cell's structure?

  • Cell membrane
  • Nucleus
  • Cytoplasm
  • Mitochondria
  • Ribosomes
• What is the function of the cell membrane?

  It controls which substances can pass in and out of the cell
• What does the nucleus contain?

  The genetic material or DNA of the cell
• What is cytoplasm and its role in the cell?

  A gel-like substance where chemical reactions take place and organelles are suspended