cell structure cell boundaries - plasma membrane
TRANSCRIPT
Cell Boundaries- Plasma Membrane
Structure• A bi-lipid envelope
around the cell that contains proteins and other markers
Function• Separates the cell from
its environment• Secretes materials out
of the cell• Recognizes friendly and
enemy objects• A selectively permeable
membrane that allows some materials to enter
- Cell Wall
Structure• A rigid covering of:
– Cellulose in plants or peptido-glycan in bacteria or chitin in fungi
Function• Gives the cell an
internal structure so it doesn’t collapse on itself
NucleusStructure
• Surrounded by a double membrane called the nuclear envelope– Has holes called
nuclear pores
Function• Holds the DNA safe
inside the cell• Controls what enters
and leaves the nucleus
DNA as 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
DNA as Chromosomes
Structure • Chromatin that is
coiled up tightly during cell division
Function• Same as chromatid
except that it is coiled up tightly so that it can be separated cleanly into the two daughter cells
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?
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
Endoplasmic Reticulum Endoplasmic Reticulum ERER
FunctionFunction
• The place where the ribosomes assemble their proteins
• Intercellular highways (where materials can move from one part of the cell to another.
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
VesiclesStructure
• Little sacs that emerge from the Golgi apparatus
Function• The transport
passage of materials within the cell
General StorageVacuoles
Structure • An empty sac is
usually large in plants
Function • Temporary storage
of water, enzymes, food particles, or waste
Lysosomes
Structure • A sac of very strong
digestive 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
ChloroplastsStructure
• Have a double membrane and their own DNA
• Contain the pigment chlorophyll
• Thylakoids look like stacks of pancakes
• Stroma fluid that surrounds the thylakoids ( sugary syrup)
Function• In the chloroplast,
thylakoids absorb solar energy and convert convert itit into into chemical energy. chemical energy. ““makes foodmakes food””
Mitochondria
Structure• Large organelles that
contain their own DNA• Has a bilayer: a smooth
outer membrane and very folded inner membrane (cristae)
MitochondriaFunction
• Releases energy in “food” into a form the cell can use which is called ATP– ATP is the currency of energy that cells use
• Parts of the body that use a lot of energy will have a lot of mitochondria (muscle cells)
• Because the mitochondria has its own DNA, it can reproduce itself.
Support and Locomotion
• Cytoskeleton: support structure/framework for the cell– Microtubules– Microfillaments
• Centrioles
• Cillia
• Flagella
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
MicrofilamentsStructure
• Long threads of protein called actin
Function• Used when the cell
moves and when a muscle cell contracts
Centrioles
Structure • Pair of small
cylindrical bodies located near the nucleus
Function• Function in cell
division
CiliaStructureStructure
• Short, “hair-like” structures that emerge from the cell membrane
• A cell may have 1000’s
Function• The cilia beat in unison or
in waves. Cilia are used to move cells – e.g. paramecium
• Cilia move mucus or fluids – e.g. over the cells of human
trachea and lungs