cell biology

• What are the two types of cells in living organisms?

  Prokaryotic and eukaryotic
• What type of cells are animal and plant cells?

  They are eukaryotic cells
• What organelles are found in animal and plant cells?

  • Cell membrane
  • Cytoplasm
  • Nucleus containing DNA
• What is the main characteristic of bacterial cells?

  They are prokaryotic and smaller
• What organelles are found in bacterial cells?

  • Cell wall
  • Cell membrane
  • Cytoplasm
  • Single circular strand of DNA
  • Plasmids
• What are organelles?

  Structures in a cell with different functions
• How do we express size differences using orders of magnitude?

  By powers of ten
• What does a size difference of 10 times bigger represent?

  It is expressed as $10^1$
• What does a size difference of 1000 times bigger represent?

  It is expressed as $10^3$
• How do we express a size difference of 10 times smaller?

  It is expressed as $10^{-1}$
• What are the prefixes used in measurements and their values?

  • Centi: 0.01
  • Milli: 0.001
  • Micro: 0.000001
  • Nano: 0.000000001
• What is the function of the nucleus in a cell?

  • Contains DNA coding for proteins
  • Enclosed in a nuclear membrane
• What is the function of the cytoplasm?

  • Liquid substance for chemical reactions
  • Contains enzymes and organelles
• What is the role of the cell membrane?

  • Controls entry and exit of substances
• What occurs in mitochondria?

  • Aerobic respiration reactions for energy
• Where does protein synthesis occur?

  • In ribosomes, on rough endoplasmic reticulum
• What is the function of chloroplasts?

  • Photosynthesis takes place
  • Contains chlorophyll for light absorption
• What is the role of the permanent vacuole?

  • Contains cell sap
  • Improves cell rigidity
• What is the function of the cell wall?

  • Provides strength to the cell
  • Made from cellulose
• How do bacterial cells differ in organelles compared to eukaryotic cells?

  They have fewer organelles and no nucleus
• What is the process of differentiation in cells?

  Cells gain new structures for specific roles
• What are examples of specialised cells in animals?

  1. Sperm cells: carry male DNA
  2. Nerve cells: transmit electrical signals
  3. Muscle cells: contract for movement
• What are examples of specialised cells in plants?

  1. Root hair cells: absorb water and minerals
  2. Xylem cells: transport water and minerals
  3. Phloem cells: carry products of photosynthesis
• What is the function of sperm cells?

  To carry male DNA to the egg
• How do nerve cells transmit signals?

  Through long axons and dendrites
• What is the role of mitochondria in muscle cells?

  To provide energy for contraction
• What is the function of root hair cells?

  To absorb water and minerals from soil
• How do xylem cells transport water?

  By forming hollow tubes with lignin
• What is the role of phloem cells?

  To carry products of photosynthesis
• What is binary fission in bacteria?

  One bacterium splits into two
• How can you calculate the number of bacteria after a certain time?

  Using the formula: initial bacteria x $2^{\text{number of divisions}}$
• What is the mean division time in bacterial growth?

  Time taken for one division to occur
• What is the purpose of soaking paper discs in antibiotics?

  To test their effectiveness against bacteria
• What does the size of the inhibition zone indicate?

  Effectiveness of the antibiotic used
• Why must inoculating loops be sterilised?

  To kill unwanted microorganisms
• Why should the Petri dish be sealed partially?

  To prevent contamination while allowing oxygen
• Why should the Petri dish be stored upside down?

  To prevent condensation disrupting growth
• Why is the incubation temperature set at 25 degrees?

  To prevent harmful bacteria growth
• What is standard form used for in microscopy?

  To handle very large or small numbers
• What is the formula for calculating the size of an object?

  Size of image / magnification