B1

• Plant and Animal cells - Eukaryotic

  nucleus- contains DNA to form chromosomes-controls most activities in cell.

  mitochondria/chloroplasts-respiration/photosynthesis occurs

  cell membrane/cell wall-control in & out of cell/ gives structural support to cell- made from cellulose

  cytoplasm/ribosomes-chemical reactions occurs-gel-like structure/proteins made

  vacuole-keep cell rigid-full of water
• photosynthetic organism (green plants + algae) use energy from the sun to make chlorophyll

  plants obtain water from roots by osmosis

  plants obtain co2 from air through stomata by diffusion
• light dependent-energy transferred from light splits water into oxygen gas and hydrogen ion

  light independent- CO2 gas combines with hydrogen ions from the light dependent stage to form glucose

  
• uses of glucose 


  sucrose- stored in fruit

  starch- food store

  cellulose-used to form cell walls

  glucose- used in respiration

  glucose+ nitrates from soil- used to make protein/amino acid

  fats&oil- used as food store and growth
• factors limiting photosynthesis

  higher light intensity= increased ROP until reaches certain amount of light- evens out and becomes plateau

  higher CO2 concentration= increased ROP until reaches certain amount of CO2-evens out and becomes plateau

  temperature increase until it reaches optimum temp- enzyme denatured and changes shape- active site won’t bind to substrate

  
• objective lens - magnifies the image to various resolution

  slide - piece of glass / plastic specimen is placed on

  fine adjusting knob - makes image clear

  coarse adjusting knob - brings stag up / down

  magnification = imagine size / real size
• stages of using light microscope

  1. — cut thin piece of specimen
  2. place drop of water onto slide + place specimen on it .
  3. stain specimen if needed + place cover slip over specimen
  4. bring coarse knob up until you see object
  5. turn fine knob until object becomes clear
• TEM - transmission electron microscope - produces most magnified image

  SEM - produces 3D images of surface only
• difference between light / EM

  • cheap / expensive
  • specimen living / has to be dead
  • small & portable / large , difficult to move
  • simple to prepare sample / hard
  • natural colour / black & white
• bacteria cells - prokaryotic

  unicellular organism - one cell

  contains cell wall , cytoplasm , cell membrane , ribsomes

  don’t have mitochondria and nucleus - has single circular strand of dna - float around

  plasmid - extra genes

  flagella - allow bacteria move around
• enzymes = used to increase rate of reaction - biological catalyst - large proteins made of long chain amino acids

  substrate = reactant

  active site = unique shape complementary to substrate
• factors affecting rate of reaction (enzymes)

  temperature & ph - enzyme has optimum temp & ph - gets higher then optimum - enzyme denatures active site changes shape - not bind to substrate

  enzyme conc & substrate conc - rate of reaction increases - become plateau - all substrate binded (enzyme conc) - all active site full (substrate conc)
• DNA - polymer , double helix - each two strands made up of lots of nucleotides

  chromosomes = long molecules of coiled up DNA

  each cell has 46 c 23 different types

  each DNA nucleotide has same sugar & phosphate group diff base
• respiration = process of transferring energy from glucose

  glucose + oxygen ➡️ c02 + water

  glucose ➡️ lactic acid 


  aerobic respiration = r with 02 - most efficient way transfer energy - takes place in mitochondria

  anaerobic respiration = without oxygen - only when we have to - eg vigorous exercise body can’t supply enough muscles

  lactic acid build up in muscles - painful makes muscles fatigued (disadv) but can keep on using muscles (adv)
• anaerobic respiration for plants & fungi 


  glucose ➡️ ethanol + co2

  under certain conditions - plant may have to resort to anaerobic resp eg waterlogged soil - plant roots cells respire anaerobically

  fungi eg yeast respire anaerobically
• similarities & differences aerobic / anaerobic resp


  conditions : o2 present / not enough o2 present eg vigorous exercise

  substrate : glucose in both (reactant)

  product : co2 + water / lactic acids or ethanol + c02 ( plants)

  energy transferred - lots - 32 ATP made / much less - 2 ATP made
• carbohydrates (CHO) - made of simple sugars eg glucose or fructose - joined together in long chains - polymers - make large complex carbohydrates eg starch & glycogen - broken down by enzymes in mouth and small intestine

  proteins (CHON) - long chains of amino acids (monomer) - broken down by enzymes in stomach and small intestine

  lipids (CHO) - made of fatty acid + glycerol - not polymer - don’t form long chain of repeating units - broke down by enzyme in small intestine
• photosynthesis happens inside chloroplasts - chlorophyll absorbs light - endothermic reaction