cell biology

• Where does aerobic respiration take place?

  mitochondria
• Where does protein synthesis occur?

  ribosomes
• Name some eukaryotic cells

  plant, animal and fungal
• Name a prokaryotic organism

  bacteria
• what is the formula for magnification?

  size of image/size of real object
• what happens before mitosis in the cell cycle?

  DNA is copied
• How many chromosomes do humans have?

  46
• What are chromosomes made of?

  DNA
• What could stem cells be used to treat?

  diabetes and paralysis
• where can you find stem cells in an embryo?

  umbilical cord
• Define diffusion


  movement of molecules from high concentration to low concentration
• Define osmosis


  The diffusion of water across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
• Define active transport


  Moves a substance from an area of lower concentration to one of higher concentration using energy from respiration.
• where is the main site of photosynthesis in a leaf?

  palisade mesophyll
• Animal and plant cells


  Organelles they both have: Nucleus, Cytoplasm, Mitochondria, Ribosomes, Cell membrane
• Plant cells


  • Vacuole, Cell wall, Chloroplasts
• Eukaryotic cells

  DNA is inside the nucleus
• Prokaryotic cells


  DNA is not in a nucleus, it is in a plasmid
• Mitosis

  1. Chromosomes are copied

  2. Chromosomes line up in the middle

  3. Chromosomes are pulled apart

  4. Daughter nuclei are formed
• Chromosomes in humans

  23 pairs, 46 total
• Meiosis

  1. DNA is copied

  2. Chromosomes swap information

  3. Two daughter nuclei are formed

  4. Four gametes with half the information are produced
• Stem cells


  Become specialized to form different cell types
• Microscopy

  • Magnification = Image size / Object size
  • Nanometers are 1 million times smaller than millimeters
  • Micrometers are 1000 times smaller than millimeters
• Electron microscopes

  Have better resolution than light microscopes, can see organelles
• DNA

  • Made up of 4 bases: A, T, C, G
  • Every 3 bases codes for an amino acid
  • Many amino acids make a protein
  • Many triplets make a gene
• Diffusion

  Particles move from high to low concentration, no energy needed
• Osmosis


  Diffusion of water through a semi-permeable membrane
• Osmosis practical

  1. Cut potato cylinders

  2. Weigh before and after soaking in sucrose solutions

  3. Heavier = water osmosed in, Lighter = water osmosed out, No change = equal concentrations
• Active transport


  Requires energy to move substances up a concentration gradient
• Chromosomes are made up of DNA coiled around proteins called histones.
• nucleus

  plant and animal
• ribosome

  plant and animal
• chloroplasts

  plant
• chloroplasts


  produce chlorophyll(make green colur)

  photosynthesis
• ribosomes

  synthesize proteins
• cytoplasm

  watery gell
• mitochondria


  where most chemical reactions take place(aerobic respiration)
• cell wall


  give its rigid shape

  controls what enters
• light microscope


  uses light and lenses to form an image
• light microscope lets us see..

  individual cells and large subcellular structures like nuclei