Biology chapter 1

• Longtitude section

  cut along the length of the cell
• Transverse section

  Cut across the length of the cell
• Cell surface membrane (plasma membrane)

  
  

  Made up of proteins and lipids

  
  

  Partially permeable, allows only small and soluble substances to pass through

  
  

  Controls movement of substances entering and exiting cell
• Cytoplasm

  Site of most cellular activities, contains organelles
• Why is the nucleus not seen

  It was cut at a place where it cannot be found
• Nucleus

  • Controls cell activities (growth and repair of damaged cells)
  • Essential for cell division
• Chromosome (part of nucleus)

  Made of proteins and DNA carrying heriditary information

  Chromatin coils and condense into chromosomes during cell divison

  Human body has 46 chromosomes
• Nuclear membrane

  Separates contents of nucleus from rest of cytoplasm
• Rough endoplasmic reticulum (part of cytoplasm)

  Network of flattened spaces lined w/ membrane

  Looks rough when looked in electron microscope due to ribosomes on surface

  Outer surface of RER continuous w/ nuclear membrane

  Transports proteins made by ribosomes to golgi apparatus
• Ribosomes

  Produces proteins

  Lies freely in cytoplasm or attached to RER

  Ribosomes attached to ER produce proteins that are secreted out of cell

  Ribosomes lying in cytoplasm produce proteins used within cytoplasm and cell
• Smooth endoplasmic reticulum (SER)

  Appears smooth due to no ribosome attached on surface

  More tubular in shape than RER

  Connected to RER

  Produces substances (e.g fats, steroids)

  Detoxifies harmful substances to harmless substances during detoxification
• Golgi body (golgi apparatus)

  A stack of flattened spaces surrounded by membranes

  Vesicles fuse w/ 1 side of golgi body, pinch off opp. side

  Chemically modifies substances produced by ER

  Stores and packages vesicles for secretion out of cell
• Mithocondria

  Site of aerobic respiration, oxidizes glucose when O2 is present to release energy for cellular activities
• Chloroplast

  Only in plant cells

  Contains chlorophyll which absorbs light for photosynthesis