cell biology - summary

• What are the four main types of cells?

  Animal, plant, yeast, and bacterial cells
• What are cells made up of?

  Cells are made up of organelles
• What is the function of the cell membrane?

  • Controls entry and exit of materials
  • Found in all types of cells
• What is the function of ribosomes?

  • Site of protein synthesis
  • Found in all types of cells
• What is the function of cytoplasm?

  • Site of chemical reactions
  • Found in all types of cells
• What is the function of mitochondria?

  • Site of aerobic respiration
  • Found in animal, plant, and yeast cells
• What is the function of the nucleus?

  • Controls the cell's activities
  • Found in animal, plant, and yeast cells
• What is the function of the cell wall?

  • Supports the cell
  • Made of cellulose in plant cells
  • Found in plant, yeast, and bacterial cells
• What is the function of vacuoles?

  • Contains cell sap
  • Found in plant and yeast cells
• What is the function of chloroplasts?

  • Site of photosynthesis
  • Found in plant cells
• What is the function of plasmids?

  • Small ring of DNA
  • Found in bacterial cells
• Why do we add a stain to microscope slides?

  To see cell organelles clearly
• What is the composition of the cell membrane?

  • Made up of proteins and phospholipids
• What is passive transport across the cell membrane?

  Movement down a concentration gradient without energy
• What is diffusion?

  • Movement of molecules from higher to lower concentration
  • No energy is needed
• What is osmosis?

  • Movement of water from higher to lower concentration
  • Through a selectively permeable membrane
  • No energy is needed
• What happens to animal cells in high water/dilute solutions?

  • Cells burst
• What happens to animal cells in low water/concentrated solutions?

  • Cells shrink
• What happens to plant cells in high water/dilute solutions?

  • Cells become turgid
  • Contents push against the cell wall
• What happens to plant cells in low water/concentrated solutions?

  • Cells become plasmolysed
  • Contents shrink and pull away from the cell wall
• What is active transport?

  Movement against the concentration gradient requiring energy
• What does DNA carry?

  • Genetic information for making proteins
  • Determines characteristics like hair and eye color
• What is a gene?

  • Codes for a particular protein
• What is the structure of DNA?

  • Made up of 2 strands
  • Twisted into a double helix shape
• What are the four bases in DNA?

  • Adenine, thymine, guanine, and cytosine

  
• What are the base pairs of DNA?

  • Adenine pairs with thymine
  • Guanine pairs with cytosine

  
• What are proteins made of?

  • Made of amino acids
  • Different types of amino acids join in different orders
• How are proteins assembled?

  • Made at ribosomes
  • mRNA carries the genetic code from DNA to ribosomes
• What determines the sequence of amino acids in a protein?

  • Determined by the sequence of bases in DNA
• What are the different types of proteins?

  • Antibodies, hormones, receptors, structural, enzymes
• What are enzymes?

  • Biological catalysts that speed up reactions
  • Unchanged after the reaction
• What is the active site of an enzyme?

  • Has a shape complementary to one substrate
  • Enzyme is specific to one substrate

  
• What are the two types of enzyme reactions?

  1. Degradation: break down large molecules
  2. Synthesis: build up large molecules
• What is an example of a degradation reaction?

  • Catalase breaks down hydrogen peroxide into oxygen and water
• What is an example of a synthesis reaction?

  • Potato phosphorylase builds starch from glucose-1-phosphate
• What are optimum conditions for enzymes?

  Conditions at which an enzyme is most active
• How can temperature and pH affect enzymes?

  • Can denature enzymes
  • Changes the shape of the active site
• What is genetic engineering?

  • Transfer of genetic information from one cell to another
• What are the stages of genetic engineering?

  1. Identify required gene
  2. Extract gene from chromosome
  3. Extract plasmid from bacterial cell
  4. Insert gene into plasmid
  5. Insert plasmid into host cell
  6. Produce protein coded by inserted gene
• What are some applications of genetic engineering?

  • Producing human proteins like insulin
  • Producing human growth hormone