Biology FlashCards

• Characteristics of living organisms


  • They require nutrition
  • They respire
  • They excrete their waste
  • They respond to their surroundings
  • They move
  • They control their internal conditions
  • They reproduce
  • They grow and develop
• Types of eukaryotic organisms


  • Animal
  • Plant
  • Fungi
  • Protoctist
• Differences between plant and animal cells


  • Plant cells have a cell wall whereas animal cells do not
  • Plant cells have a permanent vacuole whereas animal cells do not
  • Plant cells have chloroplasts and are able to photosynthesise whereas animal cells do not

  
• Structure of fungi


  • Chitin cell wall
  • Often multinucleated
  • They contain a mycelium which is made of hyphae threads

  
• How fungi feed


  They are saprotrophic so they secrete enzymes that break down their food outside of their cells and then they absorb the nutrients
• Prokaryotic cells are unicellular
• Features of prokaryotic cells


  • Cell membrane
  • Cell wall
  • Cytoplasm
  • Plasmid loops of DNA
  • No nucleus but large DNA loop instead
• Pathogen


  A disease-causing microorganism
• Types of pathogens


  • Bacteria
  • Fungi
  • Viruses
  • Protoctists
• Structure of a virus


  • Protein husk
  • Contain nucleic acid (DNA or RNA)
• Viruses


  • Tobacco mosaic virus (TMV)
  • Human immunodeficiency virus (HIV)
  • Influenza
• Bacteria


  • Lactobacillus bulgaricus - Used in the production of yoghurt from milk
  • Pneumococcus - Bacterium that causes pneumonia
• Tissue


  A group of cells working together to carry out a specific function
• Organ


  A group of tissues working together to carry out a specific function
• Organ system


  A group of organs working together to carry out a specific function
• Division of labour within a cell

  Labour is divided between the organelles
• Parts of an animal cell


  • Nucleus
  • Mitochondria
  • Ribosomes
  • Cell membrane
  • Cytoplasm
• Parts of a plant cell


  • Nucleus
  • Mitochondria
  • Ribosomes
  • Cell membrane
  • Cytoplasm
  • Permanent vacuole
  • Chloroplasts
  • Cell wall
• Functions of the nucleus


  • Controls the cell
  • Contains genetic material (in the form of chromosomes)
• Function of the cytoplasm


  It is where most of the cell's chemical reactions take place
• Function of mitochondria


  They are the site of aerobic respiration
• Function of ribosomes


  They are the site of protein synthesis
• Function and composition of the cell wall


  It provides strength and support. It is made of cellulose
• Function and contents of the permanent vacuole

  It supports the cell and contains cell sap (a solution of sugars and salts)
• Function of chloroplasts


  They are the site of photosynthesis

  
• Function of the cell membrane


  • Controls what enters and leaves the cell
  • Separates the cell from its environment
• Differentiation


  The process by which cells become specialised
• Stem cells


  Unspecialised cells that can differentiate into lots of different types of cells
• Advantages of using stem cells in medicine


  • Stem cells can be used to treat paralysis
  • Stem cells have the possibility to cure degenerative diseases like Parkinson's
  • Whole new tissues or organs can be grown that can be used to test drugs on
• Disadvantages of using stem cells in medicine


  • Using embryonic stem cells can raise ethical issues
  • It is expensive
  • Long term side effects are unknown
• Chemical elements present in biological molecules


  • Carbohydrates: Carbon, hydrogen, oxygen (C,H,O)

  Lipids: Carbon, hydrogen, oxygen (C,H,O)

  Proteins: Carbon, hydrogen, oxygen, nitrogen, sulfur (C,H,O,N,S)
• Complex carbohydrates


  Made up of simple sugars
• Proteins


  Made up of amino acids
• Lipids


  Made up of glycerol and fatty acid tails
• Enzymes


  Biological catalysts that increase the rate of metabolic reactions
• Factors affecting enzyme function


  • Temperature
  • pH
  • Substrate concentration
  • Enzyme concentration
• Effect of temperature on enzyme-controlled reactions


  • As the temperature increases, so does the rate of reaction
  • Once the temperature exceeds the optimum, the enzyme denatures and the rate of reaction decreases
• Why temperature increases rate of enzyme-controlled reactions

  As the temperature increases the particles have more kinetic energy, this increases the chance of collisions between molecules being successful and leading to a reaction
• Effect of high temperature on enzyme function


  The active site will be distorted as the enzyme denatures and so it will no longer fit the substrate
• Effect of pH on enzyme-controlled reactions


  • The rate of an enzyme catalysed reaction is fastest at the optimum pH
  • If the pH is too high or low, the enzyme will work less efficiently and the active site may be denatured at extremes of pH