Unit 2

• Description of cell-surface membrane.


  Description:

  • The membrane found on the surface of animal cells and just inside the cell wall of other cells
  • Mainly made of lipids and proteins
• Function of cell surface membrane


  Functions:

  • (aka plasma membrane)
  • regulates movement of substances into and out of the cell
  • also has receptor molecules - allow it to respond to chemicals like hormones
• Description of the nucleus


  Description:

  • large organelle surrounded by a nuclear envelope (aka double membrane)
  • nucleus contains chromosomes and one or mores structures called nucleolus
• Function of nucleus:

  Function:

  • controls the cell's activities
  • contains instructions to make proteins
  • pores allow substances to move between the nucleus and the cytoplasm
  • nucleolus makes ribosomes
• Description of Mitochondrion

  Description:

  • usually oval-shaped
  • inner one is folded to form structures called cristae
  • inside is the matrix, which contains enzymes involved in respiration
• Function of the Mitochondrion

  Function:

  • site of aerobic respiration
  • aerobic respiration produces ATP - common energy source in cell
  • found in large numbers in cells - very active and require lots of energy
• Description of golgi apparatus

  Description:

  • group of fluid-filled membrane-bound flattened sacs
  • vesicles often seen at the edges of the sacs
• Function of golgi apparatus

  function:

  • processes and packages new lipids and proteins
  • also makes lysosomes
• Description of golgi vesicle

  Description:

  • small fluid-filled sac in the cytoplasm
  • surrounded by a membrane and produced by the golgi apparatus
• function of the golgi vesicle

  function:

  • stores lipids and proteins made by the golgi apparatus
  • and transports them out of the cell
• Description of lysosome

  description:

  • round organelle surrounded by a membrane with no clear interal structure
• function of lysosome

  function:

  • contains hydrolytic enzymes
  • these are separate from cytoplasms by the surrounding membrane
  • and can be used to digest invading cells
  • or to break down worn out components of the cell
• description of ribosome

  description:

  • very small organelle that floats free in the cytoplasm
  • or is attached to the rough endoplasmic reituclum
  • made up of proteins and RNA
  • not surrounded by a membrane
• function of ribosome

  function:

  • site where proteins are made
• Description of rough endoplasmic reticulum (RER)

  description:

  • system of membranes enclosing a fluid filled space
  • surface is covered with ribosomes
• function of rough endoplasmic reticulum (RER)

  funtion:

  • folds and processes proteins that have been made at the ribosomes
• description of smooth endoplasmic reticulum (SER)

  description:

  • system of membranes enclosing a fluid-filled space
  • has NO ribosomes on surface
• function of smooth endoplasmic reticulum

  function:

  • synthesises and processes lipids
• description of chloroplast

  description:

  • small, flattened structure in plant and algal cells
  • surrounded by a double membrane
  • also has membranes inside called thylakoid membranes
  • these membranes are stacked in some parts of the chloroplast to form grana
  • grana are linked together by the lamaellae - thin, flat pieces of thylakoid nenbrane
• function of chloroplast

  function:

  • site where photosynthesis takes place
  • some parts of photosynthesis happen in the grana and others in the stroma
  • stroma - thick fluid found in plants
• description of cell wall

  description:

  • rigid structure that surrounds cells in plants, algae and fungi
  • in plants and algae its mainly of carbohydrate cellulose
  • in fungi, its made of chitin
• function of cell wall

  function:

  • supports cells and prevents them from changing shape
• description of cell vacuole

  description:

  • membrane-bound organelle found in cytoplasm
  • contains cell sap - weak solution of sugar and salt
  • surrounding membrane is called the tonoplast
• function of cell vacuole

  function:

  • helps maintain pressure inside the cell
  • keep cell rigid - stops plant wilting
  • isolates unwanted chemicals inside the cell
• define prokaryotic cells

  they're single-celled organisms

  • no nucleus
  • smaller and simpler than eukaryotic
• define eukaryotic cells

  they're single-cell organisms whose cells contain a distinct membrane bound nucleus
• there are four types of eukaryotic cells

  they're

  1. animal
  2. plant
  3. algae
  4. fungal
• (prokaryotic) cytoplasm

  • has no membrane bound organelles
  • has ribosomes (smaller than eukaryotic cells)
• (prokaryotic) flagellum

  • long, hairline structure that rotates to make prokaryotic cell move
  • not all have flagellum/some have more than 1
• (prokaryotic) DNA

  • present as one long coiled-up strand
  • not attached to any histone proteins
• (prokaryotic) Plasmids

  • are small loops of DNA that aren't main circular DNA
  • contain genes for things e.g antibiotic resistance
  • some cells may have no plasmids, some may have many
• (prokaryotic) capsule

  • made of secreted slime
  • helps to protect bacteria from attack by cells of the immune system
• (prokaryotic) Cell wall

  • supports cell and prevents shape changing
  • made of a polymer called murein
• (prokaryotic cell wall) define murein

  • is a glycoprotein (protein with a carbohydrate attached)
• (prokaryotic) plasma membrane

  • mainly made of lipids and proteins
  • controls the movement of substances in/out of cell