Cells

• Mitosis

  1. Interphase

  2. Mitosis

  3. Cytokinesis (cell division)
• Mitosis (eukaryotic cells)


  • 2 identical daughter cells are formed
  • Daughter cells are genetically identical to the original cell
• Daughter cells


  Cells that result from a division of a single parent cell
• Stages of Mitosis


  1. Cell grows and makes copies of organelles

  2. Chromosomes replicate

  3. Two sets of chromosomes pulled to opposite sides

  4. Two new nuclei form

  5. Cell splits into two daughter cells
• Differences between Mitosis and Meiosis

  • Mitosis produces 2 daughter cells, Meiosis produces 4 gametes
  • Mitosis has 1 cell division, Meiosis has 2 cell divisions
  • Mitosis creates diploids, Meiosis creates haploids
  • Mitosis creates genetically identical cells, Meiosis creates genetically different cells
  • Mitosis used for growth, repair & asexual reproduction, Meiosis used to create gametes & sexual reproduction
• Meiosis


  Process used in sexual reproduction to create gametes (sperm and eggs)
• Stages of Meiosis

  1. Copies of genetic information made

  2. Cell divides twice to form four gametes, each with a single set of chromosomes

  3. Gametes are haploid and genetically different
• Binary Fission

  1. Genetic material replicates

  2. Circular DNA moves to opposite poles

  3. Cytoplasm divides and cell walls form around two new daughter cells
• Types of Cells

  • Eukaryotic
  • Prokaryotic
  • Animal
  • Plant
  • Bacterial
• Eukaryotic Cells


  Cells that have a nucleus, often multicellular, more complex
• Prokaryotic Cells


  Cells that don't have a nucleus, often single celled, much simpler and smaller
• Animal Cell

  • Ribosomes produce protein
  • Cytoplasm contains nutrients and enzymes
  • Nucleus holds DNA and controls cell
  • Mitochondria allow respiration and release energy
  • Cell membrane controls what comes in and out
• Plant Cell

  • Contains all the features of an animal cell plus:

  Cell wall made of cellulose providing structure

  Vacuole holds cell sap for osmosis and keeps cell swollen

  Chloroplast allows photosynthesis to take place
• Bacterial Cell

  • Do not have nucleus, DNA is free in cytoplasm

  Have a main circular strand of DNA and some additional small rings of DNA called plasmids

  Do not have chloroplast or mitochondria

  Some may have a flagella which helps with movement
• Specialisation in Animal Cells

  • Sperm cells
  • Nerve Cells
  • Muscle Cells
• Sperm Cells

  • Transport male DNA for sexual reproduction

  Has enzymes that digest egg cell membrane

  Lots of mitochondria to provide energy

  Tail for movement
• Nerve Cells

  • Carry electrical impulses around the body

  Long axon to carry impulse over long distances

  Branched at both ends to pass signals

  Fatty sheath helps impulses move quicker
• Muscle Cells

  • Must contract quick so require mitochondria

  Protein filaments that slide over to cause the muscle to contract
• Specialisation in Plant Cells

  • Root hair cell
  • Xylem Cell
  • Phloem Cell
• Root Hair Cell

  • Specialised to absorb water and nutrients

  Found on roots of plants increasing surface area

  Has a vacuole full of cell sap, creating water potential gradient

  Lots of mitochondria for active transport of mineral ions
• Xylem Cell

  • Vessels transport water and dissolved ions

  Cells are dead and hollow and doesn't have cytoplasm

  Water is drawn upwards due to the lack of top and bottom cell walls
• Phloem Cell

  • Transports sugars and amino acids

  Cells are joined end to end with sieve plates

  Cells are living despite also having few subcellular structures
• Types of Transport in Cells

  • Diffusion
  • Osmosis
  • Active Transport
• Diffusion

  The net movement of particles from an area of high concentration to an area of low concentration, down a concentration gradient
• Osmosis

  Water travels from a dilute solution (high water concentration) to a more concentrated solution (low water concentration) across a partially permeable membrane
• Active Transport

  Movement from an area of low concentration to high concentration, against a concentration gradient, requires ATP energy
• To increase rate of diffusion: increase temperature, increase surface area, increase concentration gradient, shorten distance
• Organisms with large surface areas have a higher diffusion rate
• Net movement of diffusion = particles in - particles out
• Types of Osmotic Solutions

  • Isotonic
  • Hypotonic
  • Hypertonic
• Active transport allows substances to travel from an area of low concentration to high concentration, against the concentration gradient
• Gametes = sperm and eggs

  Diploids = chromosome pairs ( one from mother and one from father )

  Haploids = having one copy of each chromosome
• BINARY FISSION


  A type of cell division where a single cell splits into two identical daughter cells, resulting in genetically identical cells.
• CELL DIVISION


  The process by which a cell divides into two or more daughter cells, resulting in increased population numbers or specialized cell types.
• ASEXUAL REPRODUCTION


  The production of offspring without the fusion of gametes (sperm and egg cells), resulting in genetically identical offspring.
• MITOSIS


  A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus.
• PROKARYOTIC CELLS


  Single-celled organisms without a true nucleus, typically bacteria.