section 1 cell structures and ultrastructures
DESCRIPTION
Section 1 Cell Structures and Ultrastructures. Cell Compartmentalization. Organelles - “ tiny organs ” inside the cell have a specific job to maintain homeostasis (healthy cell) Some are in all cells Some are only found in either animal or plant cells. - PowerPoint PPT PresentationTRANSCRIPT
Section 1Cell Structures
and Ultrastructures
Cell Compartmentalization
Organelles of an Animal CellStructure- parts of a cell visible through a
light microscope
Ultrastructure- parts of a cell visible through
only an electron microscope
Plasma Membrane- “wall and gate” of the
cell; 7nm wide
•Selective permeability - allows some
molecules to pass through while keeping
others out.
•Transport proteins- special tunnels or
doors that only let in specific molecules
The Nucleus
•The “brain” of the cell; contains
loosely coiled DNA (Chromatin)
• Nucleolus- Compact, largely
inactive DNA in chromosome
form
•Makes ribosomes
• Nuclear envelope- two
membrane outer layer
•Nuclear pores- small openings
to allow exchange of materials
The ERsEndoplasmic Reticulum- system of membrane sacs (cristernea) branching off of the nucleus; does various of chemical reactions
Smooth ER- no ribosomes; makes lipids and hormones
Rough ER- ribosomes; makes proteins
Ribosomes- take copy of DNA’s information (mRNA) and use it as a guide to create proteins
ER ribosomes- proteins move on to Golgi apparatus
Free ribosomes- proteins move to cytoplasm
Golgi ApparatusGolgi Apparatus- membrane sacs (cisternae) that put proteins into small membrane-bound packages called vesicles which are sent out or around the cell; makes lysosomes
Lysosomes- sacs of hydrolytic enzymes that digest old organelles, food, and viruses/bacteria
The Mitochondria• power house of the cell; produces ATP(energy unit for cells) by breaking down sugars and other organic compounds (aerobic respiration)•Two membranes with inner one folded into cristae•Matrix (inner area) produces ATP and lipids
Organelles for Support
Cytoplasm- clear gel-like fluid inside cells; help holds organelles in place
Cytoskeleton- “Bones” of the cell; crossing rods, filaments, and tubes, that hold the cells shape. Also act at a
“train” system to move things around the cell
Cilia and Flagella
Flagella- long, wipe-like tail that pushes and rolls the cell
Cilia- short, hair-like paddles that push the cell along
Both made from microtubules that form a basal body
Basal body- cylinder shape of 9 pairs of tubules + 2 central tubes•9 + 2 formation
Centrioles
• two 9+2 cylinders stuck at 90o from each other• move chromosomes during cell division by growing spindle fibers• animal cells only
Organelles of a Plant Cell•The organelles already covered (except centrioles, cilia, and flagella) can also be found in plant cells•Plants have a few extra organelles
Cell wall- thick, rigid wall made of cellulose that gives the plant cell a definite shape
Plasmodesmata- small connecting points between the cells walls of neighboring plant cells; allow exchange
Photosynthesis CentersChloroplasts- perform photosynthesis to make energy from
sunlight in planets and some unicellular organisms
Chlorophyll- chemical that absorbs wavelengths of sunlight, expect green
Grana- stacks of membranes containing chlorophyll
Vacuoles- Both Large and Small
Vacuoles- storage compartments for food, enzymes, etc.• In plant cells- they are very large and hold lots of water
and nutrients; tonoplast membrane controls exchange; also holds pigments the give flowers color• In animal cells- very small; transport things inside the
cell
Animal Cells Vs. Plant CellsOrganelle Plants only Animals only Both
Plasma Membrane
X
Cell Wall X
Nucleus X
Ribosomes X
Endoplasmic Reticulum
X
Gogi Apparatus X
Cilia/Flagella (Extremely Rare)
X
Lysosome X
Vacuole (large) (small) X
Centrioles X
Mitochondria X
Chloroplasts X
Homework• Review
Section 1 for a quiz next Tuesday• Cell Analogy
worksheet