Nat 5 Biology

• Plant Cell


  Cell wall, mitochondrion, chloroplast, cell membrane, cytoplasm, vacuole, nucleus, ribosome

  
• Animal Cell

  Mitochondrion, cell membrane, cytoplasm, nucleus, ribosome

  
• Fungal Cell


  Cell wall, mitochondrion, cell membrane, cytoplasm, vacuole, nucleus, ribosome
• Bacterial Cell


  Cell wall, cell membrane, ribosome, plasmid

  
• Cell Wall

  Gives cell a rigid structure
• Mitochondrion


  Site of aerobic stages of respiration

  
• Cell Membrane


  Controls movement of substances in and out of the cell

  
• Chloroplasts


  Site of photsynthesis

  
• Cytoplasm


  Site of many chemical reactions

  
• Nucleus


  Controls cell activities, contains DNA

  
• Vacuole


  Stores cell sap, helps control water balance

  
• Ribsome


  Site of protein synthesis

  
• Plasmid


  Ring of DNA that can be removed in genetic engineering

  
• Cell Wall in Plant Cells

  Made of cellulose
• Cell Membrane Consists of...

  Proteins and phospholipids
• Cell Membrane is...


  Selectively permeable
• Between Cells and Their Environment...

  Different concentrations of substances exist
• Active Transport


  Requires energy for membrane proteins to move molecules and ions against the concentration gradient
• Passive Transport


  Involves substances moving down a concentration gradient and does not require energy
• Examples of Passive Transport

  Diffusion and osmosis
• Diffusion


  Movement of molecules down a concentration gradient
• Diffusion of Glucose and Oxygen


  Move into cell by diffusion. Concentration gradient running from outside of the cell to the inside
• Diffusion of Carbon Dioxide

  Move out of cell by diffusion. Concentration gradient running from inside the cell to the outside
• Osmosis


  Movement of water molecules from a higher to lower water concentration through a selectively permeable membrane
• Animal Cells can...


  Burst when placed in solutions with a higher water concentration than their cell content
• Plants Cells can...


  Become turgid if left in solutions with higher water concentration
• Animal Cells Shrink...


  If placed in a solution with lower water concentration than their cell content
• Plant Cells Plasmolyse...


  If placed in a solution with lower water concentration than their cell content
• Structure of DNA


  Double-stranded helix
• DNA


  Carries genetic information for making protein
• Four Bases


  Adenine, Cytosine, Guanine, Thymine
• Bases Pairing


  A-T, C-G
• Genetic Code


  The sequence of bases along a strand
• Base Sequence Determines...


  Amino acid sequence in proteins
• Genes


  Section of DNA that codes for proteins
• Messenger RNA (mRNA)


  Molecule that carries a complementary copy of the genetic code from DNA, in nucleus, to a ribosome, where protein is assembled from amino acids
• Variety of Protein Shapes and Functions...

  Arises from sequence of amino acids
• Functions of Proteins


  Structural, enzymes, hormones, antibodies, receptors
• Enzymes


  Biological catalyst and are made by all living cells
• Function of Enzymes


  Speed up cellular reactions and are unchanged in the process