Cell Organelles and their Functions Chapter 4 Section 2
Dec 18, 2015
Cell Organelles and their Functions
Chapter 4 Section 2
1. Cell Membrane
Structure• A phospholipid bi-
layer around the cell that contains proteins and other markers
Function• Separates the cell from
its environment• Secretes materials out of
the cell• A selectively (semi)
permeable membrane that recognizes friendly and enemy objects and allows some materials to enter
2. Mitochondria
Structure• Large organelles that
contain their own DNA• Has a bilayer
membrane: a smooth outer membrane and very folded inner membrane (cristae)
2. Mitochondria2. MitochondriaFunctionFunction
• Releases energy in “food” into a form Releases energy in “food” into a form the cell can use which is called ATP the cell can use which is called ATP (cellular respiration) ATP is the currency (cellular respiration) ATP is the currency of energy that cells useof energy that cells use
• Parts of the body that use a lot of Parts of the body that use a lot of energy will have a lot of mitochondria energy will have a lot of mitochondria (muscle cells)(muscle cells)
• Because the mitochondria has its own Because the mitochondria has its own DNA, it can reproduce itself.DNA, it can reproduce itself.
3. Ribosomes
Structure • Each cell has 1000’s
of ribosomes which are little spheres
• A ribosome contains a protein connected to some RNA. Ribosomes don’t have membranes
Function• Protein Synthesis
• What is the function of What is the function of nucleic acids?nucleic acids?
4. Endoplasmic Reticulum ER
Structure
• A membrane system of folded sacs and tunnels
• When it is covered with lots of ribosomes= rough ER
• When it lacks ribosomes= smooth ER
4. Endoplasmic Reticulum 4. Endoplasmic Reticulum ERER
FunctionFunction
• The place where the ribosomes The place where the ribosomes assembles their proteinsassembles their proteins
• Intercellular highways: Intercellular highways: where where materials can move from one part materials can move from one part of the cell to another. of the cell to another.
5. Golgi ApparatusStructure
• A system of flattened sacs & membranes that emerge from the ER
Function• Modifies the
proteins made in the ER so they can be put into packages and exported from the cell
6. Vesicles
Structure • Little sacs that emerge
from the Golgi apparatus
Function• The transport
passage of materials within the cell
7. LysosomesStructure
• A sac of very strong enzymes in a double membrane
• Common in animal, fungi and protist cells, but are rare in plant cells
Function• Used to digest food
molecules and invaders of the cell
• Sometime used to “self destruct” cells suicide sacs
8. Nuclear Membrane or nuclear envelope
Structure• A double membrane
• Has holes called nuclear pores
Function• Holds the DNA safe
inside the cell• Controls what enters
and leaves the nucleus
9. Nucleolus
Structure• A spherical body in
the nucleus
Function• Makes the ribosomes
10. Chromatin
Structure• A fine strand of DNA
coiled around proteins
Function• Contains all the
information for making proteins
• Is the inherited information that is given to the offspring during reproduction
11. Chromosomes11. Chromosomes
StructureStructure • Chromatin that is Chromatin that is
coiled up tightly coiled up tightly during cell divisionduring cell division
FunctionFunction• Same as chromatin Same as chromatin
except that it is coiled except that it is coiled up tightly so that it can up tightly so that it can be separated cleanly be separated cleanly into the two daughter into the two daughter cellscells
12. Microfilaments
Structure• Long threads of
protein called actin
Function• Used when the cell
moves and when a muscle cell contracts
13. Microtubules
Structure • Long, slender tubes
of protein
Function• Gives structure to
the cell so it doesn’t collapse on itself
• During cell division, microtubules are used to pull apart the chromosomes into the new daughter cells
14. Cilia
StructureStructure• Short, “hair-like” Short, “hair-like”
structures that structures that emerge from the cell emerge from the cell membranemembrane
• A cell may have A cell may have 1000’s1000’s
FunctionFunction• The cilia beat in unison or The cilia beat in unison or
in waves. Cilia are used to in waves. Cilia are used to move cells move cells – e.g. parameciume.g. paramecium
• Cilia move mucus or fluids Cilia move mucus or fluids – e.g. over the cells of human e.g. over the cells of human
trachea and lungstrachea and lungs– Female reproductive Female reproductive
systemsystem
15. Flagellum
Structure• A long “whip-like”
structure that emerges from the cell membrane
• A cell has only 1-2 flagella
Function • Whip back and forth
to move a cell through fluid (e.g. sperm or Euglena)
16. Cell Wall
Structure• A rigid covering of:
– Cellulose in plants
Function• Gives the cell an
internal structure so it doesn’t collapse on itself
What does an animal cell have to not collapse?
17. Vacuoles
Structure • An empty sac is
usually large in plants
Function • Contains one of
these materials:• Water, enzymes,
food particles, or waste
18. Plastids(chloroplast)
Structure• Have a double
membrane and their own DNA
• Some plastids have thylakoids which contain pigments
• Thylakoids look like stacks of pancakes
Function• A chloroplast
contains thylakoids which absorb solar energy. Then converts it into converts it into chemical energy. chemical energy. “makes food”“makes food”
19. Centrioles
Structure • Pair of small
cylindrical bodies located near the nucleus
Function• Function in cell
division