Organelles

• Structure and function of the nucleus


  Contains cell’s genetic material

  Structure: chromatin (mix of DNA and proteins that form chromosomes), nuclear envelope (pores that allow mRNA and nucleotides to pass), nucleolus (makes rRNA and assemble ribosomes), nucleoplasm
• structure and function of chloroplasts


  the site where photosynthesis takes place

  structure: small, flattened structure found in plant cells, double membrane, stroma (matrix), thylakoids, granum (stacks of thylakoids), lamella.
• structure and function of centriole


  involved with the separation of chromosomes during cell division

  structure: small, hollow cylinders, made of microtubules.
• Structure and function of plasma membrane


  Regulates the movement of substances into and out of the cell. Contains receptor molecules on it, so can respond to chemicals like hormones.

  Structure: phospholipid bilayer, proteins, lipids
• Golgi apparatus


  It processes and packages new lipids and proteins. It makes lysosomes.

  Structure: group of fluid filled sacs, membrane-bound, flattened sacs. Vesicles present.
• rough endoplasmic reticulum (RER)


  involved in the transport and synthesis of proteins

  structure: lots of ribosomes on surface of cell, system of membranes enclosing a fluid filled space.
• cilia


  contain microtubules that allow cilia to move substances along the cell surface.

  structure: small, hair-like. outer membrane and ring of 9 pairs of protein microtubules with 2 in middle.
• flagellum


  contains microtubules that contract to cause the flagellum to move like outboards motors to propel cells forward. (Sperm cells swim)

  Structure: like cilia but longer, small microtubule arrangement.
• mitochondria


  the site of aerobic respiration, where ATP is produced.

  structure: oval shaped, double membrane - inner cristae (folds) and inside is matrix.
• cell wall


  supports plant cells

  structure: rigid structure, made mainly of carbohydrate cellulose
• lysosome


  contains digestive enzymes. used to digest invading cells or to break down worn down components.

  structure: round organelle, surrounded by membrane
• ribosome


  the site where proteins are made

  structure: very small, floats in cytoplasm or attached to RER. made of proteins and RNA. not membrane bound
• smooth endoplasmic reticulum (SER)


  Involved in the transport and synthesis of lipids

  Structure: no ribosomes
• Organelles involved in protein production


  nucleus - mRNA

  Nuclear envelope

  Ribosome - proteins made

  RER - proteins folded and processed

  Vesicles

  Golgi apparatus -further processing

  Vesicles
• 4 main functions of the cytoskeleton


  microfilaments and microtubules support and keep organelles in position.

  help strengthen and maintain cell shape.

  responsible for the movement of materials within the cell.

  proteins of cytoskeleton can cause movement.
• compare prokaryotes and eukaryotes

  Prok are very small (>2micromete in diameter) whereas Euk are larger (10-100 in diameter). Prok DNA is circular whereas Euk DNA is linear. Prok have no nucleus but Euk does. Prok cell wall made of peptidoglycan whereas Euk only plants have it (cellulose). Prok have few organelles and none are membrane bound whereas Euk have lots and many are membrane bound. Prok flagellum made of protein flagellin arranged in helix whereas Euk flagellum made of microtubules arranged in 9+2 formation.
• structures of bacterial cells


  Flagellum

  no nucleus

  Plasma membrane

  Ribosome

  Plasmid

  Cell wall
• define magnification


  is how much bigger the image is than the specimen
• define resolution 


  the ability to distinguish between two points
• magnification equation


  mag = image/actual
• name 2 types of microscopes


  light

  electron - TEM and SEM
• features of light microscope


  uses light

  lower resolution (max=0.2 micrometers)than electron.

  lower magnification(max x1500)

  uses live specimen - whole cells or tissues

  cheaper

  in schools
• features of electron microscope


  uses electrons

  higher resolution - look at cells in greater detail

  higher magnification

  more expensive

  dead specmien’s
• features of transmission electron microscope


  uses elecromagnets to focus beam of electrons, which is transmitted through specimen.

  high resolution images - look at range of organelles

  only thin specimens
• features of scanning electron microscope


  scan beam of electrons across specimen.

  shows surface of specimen and can be 3D

  lower resolution images
• Nucleus

  contains cells genetic material

  A) nuclear pores

  B) nuclear envelope

  C) nucleolus

  D) chromatin

  E) nucleoplasm