BRAINCAKE

Cells and control

Edexcel GCSE Combined ScienceTopic 2 of 1431 lessons

Revision notes for Cells and control in Edexcel Combined Science (1SC0). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.

  1. Mitosis and the cell cycleCells go through a repeating series of events called the cell cycle.
  2. Why mitosis is importantMitosis is the type of cell division that produces new body cells.
  3. Mitosis makes identical diploid cellsWhen a cell divides by mitosis, one parent cell makes two daughter cells.
  4. Cancer and uncontrolled cell divisionNormally the rate of cell division in the body is carefully controlled, so cells divide only when new cells are needed.
  5. Growth in animals and plantsOrganisms grow by increasing the number of their cells.
  6. The importance of cell differentiationA multicellular organism begins as a single cell, and its cells are all alike at first.
  7. Percentile charts and growthDoctors use percentile charts to monitor the growth of babies and children.
  8. Stem cells and meristemsA stem cell is an undifferentiated cell.
  9. Stem cells in medicine: benefits and risksStem cells could be used to replace damaged cells and tissues.
  10. Neurones, receptors and synapsesSensory receptors detect a stimulus, such as light, pressure or a change in temperature, and produce an electrical impulse.
  11. The reflex arcA reflex action is a fast, automatic response to a stimulus.
  12. Interpreting paper chromatogramsPaper chromatography separates a mixture of soluble substances.
  13. Core practical: inks, chromatography and simple distillationThis core practical has two parts, and both use ink.
  14. Making water potableWater that is safe to drink is called potable water.
  15. Newton's second lawWhen the forces on an object are not balanced, there is a resultant force and the object accelerates.
  16. Weight, mass and W = m × gWeight is the force acting on an object because of gravity.
  17. Measuring weightWeight is a force, so it is measured with a newtonmeter, also called a spring balance.
  18. Weight and gravitational field strengthGravitational field strength, g, tells you how strong gravity is in a place.
  19. Core practical: force, mass and accelerationThis practical tests Newton's second law, F = m × a.
  20. Circular orbits and changing velocitySpeed tells you how fast an object moves.
  21. Centripetal forceTo move in a circle, an object needs a resultant force acting towards the centre of the circle.
  22. Inertial massInertial mass is a measure of how difficult it is to change the velocity of an object.
  23. Newton's third lawNewton's third law says that when object A exerts a force on object B, object B exerts an equal and opposite force on object A.
  24. MomentumMomentum is a measure of how much motion an object has.
  25. Examples of momentum in collisionsMomentum is mass multiplied by velocity, so it has a direction as well as a size.
  26. Force as change in momentum over timeNewton's second law can be written using momentum: force = change in momentum ÷ time taken.
  27. Measuring human reaction timesA person's reaction time is the time between seeing or hearing a signal and responding to it.
  28. Stopping distanceWhen a driver sees a hazard, the vehicle does not stop at once.
  29. Factors affecting stopping distanceSeveral factors change the stopping distance of a vehicle, and each one affects either the thinking distance, the braking distance or both.
  30. Factors affecting a driver's reaction timeA driver's reaction time is not fixed.
  31. Dangers of large decelerations and estimating forces on the roadWhen a vehicle crashes, it slows down very quickly.

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