Summary

• What are the distinguishing features of eukaryotic cells?

  Cytoplasm with organelles, DNA in nucleus
• What is the general structure of an animal cell?

  • Cell-surface membrane
  • Mitochondrion
  • Nucleus
  • Ribosomes
  • Rough endoplasmic reticulum (rER)
  • Smooth endoplasmic reticulum (sER)
  • Golgi apparatus
  • Lysosome
• What is the general structure of a plant cell?

  • Chloroplast
  • Cell wall
  • Cell vacuole
• What is the structure of the cell-surface membrane?

  Phospholipid bilayer with proteins
• What is the function of the cell-surface membrane?

  Controls passage of substances in/out
• What is the structure of the nucleus?

  Double membrane with nuclear pores
• What is the function of the nucleus?

  Stores genetic information and codes for proteins
• What is the structure of a ribosome?

  Made of rRNA and protein, no membrane
• What is the function of a ribosome?

  Site of protein synthesis (translation)
• What are the structures and functions of rough and smooth endoplasmic reticulum?

  Rough Endoplasmic Reticulum (rER):

  • Has ribosomes on surface
  • Synthesizes, processes, and transports proteins

  
  

  Smooth Endoplasmic Reticulum (sER):

  • No ribosomes
  • Synthesizes and processes lipids (e.g., cholesterol, steroid hormones)
• What is the structure of the Golgi apparatus?

  Flattened membrane sacs
• What is the function of the Golgi apparatus?

  Modifies and packages proteins and lipids
• What is the structure of lysosomes?

  Membrane with hydrolytic enzymes
• What is the function of lysosomes?

  Breaks down pathogens and worn-out components
• What is the structure of mitochondria?

  Outer membrane, cristae, matrix
• What is the function of mitochondria?

  Site of aerobic respiration, produces ATP
• What is the structure of chloroplasts?

  Double membrane, stroma, thylakoid membranes
• What is the function of chloroplasts?

  Absorbs light energy for photosynthesis
• What is the structure of the cell wall in plants?

  Composed mainly of cellulose
• What is the function of the cell wall in plants?

  Provides mechanical strength to the cell
• What is the structure of the cell vacuole in plants?

  Tonoplast membrane and cell sap
• What is the function of the cell vacuole in plants?

  Maintains turgor pressure and stores substances
• How are eukaryotic cells organized in multicellular organisms?

  • Cells become specialized for specific functions
  • Tissue: Group of specialized cells
  • Organ: Aggregation of tissues
  • Organ system: Group of organs
• How can you explain adaptations of eukaryotic cells using organelles?

  Named cell has many organelles for function
• What are the distinguishing features of prokaryotic cells?

  Cytoplasm without organelles, no nucleus
• What is the general structure of prokaryotic cells?

  • Capsule (sometimes present)
  • Cell-surface membrane
  • Cell wall (contains murein)
  • Plasmids (small rings of DNA)
  • Flagella (sometimes present)
  • Cytoplasm with small ribosomes and circular DNA
• Compare the structure of eukaryotic and prokaryotic cells.

  Eukaryotic Cells:

  • Membrane-bound organelles
  • Has a nucleus
  • Long, linear DNA with histones
  • Larger ribosomes (80S)
  • Cell wall only in plants, algae, fungi

  
  

  Prokaryotic Cells:

  • No membrane-bound organelles
  • No nucleus
  • Short, circular DNA without histones
  • Smaller ribosomes (70S)
  • Cell wall in all, containing murein
• Why are viruses described as acellular and non-living?

  Not made of cells, no metabolism
• What is the general structure of a virus particle?

  Nucleic acids surrounded by a capsid
• What are the principles of magnification and resolution?

  Magnification is image size vs real size
• Compare optical microscopes, TEMs, and SEMs.

  Optical Microscopes:

  • Light focused with glass lenses
  • 2D image, low resolution
  • Can view living organisms

  
  

  Transmission Electron Microscopes (TEM):

  • Electrons focused with electromagnets
  • 2D image, high resolution
  • Can only view dead specimens

  
  

  Scanning Electron Microscopes (SEM):

  • Electrons focused with electromagnets
  • 3D image, high resolution
  • Can only view dead specimens
• What is the formula for magnification?

  Magnification = size of image / size of real object
• What are the steps in calculations involving magnification?

  1. Note formula / rearrange if necessary
  2. Convert units if necessary
  3. Calculate answer and check units
• How to convert between different units?

  • Centimetre (cm): 1/100 m
  • Millimetre (mm): 1/1000 m
  • Micrometre (µm): 1/1000000 m
  • Nanometre (nm): 1/1000000000 m
• How to measure the size of an object with an optical microscope?

  1. Line up eyepiece graticule with stage micrometre
  2. Calibrate eyepiece graticule
  3. Measure object with graticule
  4. Calculate size of object
  5. Recalibrate at different magnifications
• What are the principles of cell fractionation and ultracentrifugation?

  • Cell fractionation: Separates cell components
  • Ultracentrifugation: Uses high speeds to separate organelles
• What is the first step in measuring an object using a graticule?

  Take micrometre away and use graticule
• How do you calculate the size of an object using a graticule?

  Multiply number of divisions by size of division
• Why is it necessary to recalibrate the eyepiece graticule?

  To ensure accurate measurements at different magnifications
• What is the size of one eyepiece graticule division if 4 divisions equal 100 µm?

  25 µm