Transcript Cell Structure & Function

Cell Structure &
Function
Cell Theory
• All living things are made of cells
• Cells are the basic unit of structure and
function in organisms
• Cells only come from pre-existing cells
• Schleiden, Schwann, & Virchow
Cell Diversity
• Differ in size, shape, &
function
• Shape determines
function
Prokaryotes
• “Pro-” = before
• “-karyote” = nucleus
• No nucleus
• No membrane-bound organelles
• Unicellular
• Found in Kingdoms Archaebacteria and
Eubacteria
Eukaryotes
• “Eu-” = true (true nucleus)
• Have a nucleus and membrane-bound
organelles
• Unicellular or Multicellular
• More complex than prokaryotes
• Found in Kingdoms Animalia, Plantae,
Protista, & Fungi
Cell Membrane
• Surrounds the entire cell
• Controls what enters and leaves the cell
• Made of:
• Phospholipids (heads and tails)
• Proteins
• Carbohydrates
• Cholesterol
• Steroids
Nucleus
• Control center of the cell (“brain”)
• Surrounded by a membrane (nuclear
envelope)
• Membrane contains pores
(communication)
• Houses DNA (chromatin)
• Contains nucleolus (where RNA is
made)
Cytoplasm
• Includes everything between the cell
membrane and the nucleus
• Jelly-like
• Made up of organelles and cytosol
(water and proteins)
Ribosomes
• Site of protein synthesis
• Made up of rRNA and proteins
• Not surrounded by a membrane
• Located in the cytoplasm or attached to
rough ER
Rough Endoplasmic
Reticulum
• “Roadway” of the cell
• Helps in making and transporting
proteins
• Ribosomes are on the surface - give
“rough” appearance
• Endoplasmic Reticulum = ER
Smooth ER
• “Roadway” of the cell
• Helps cell to break down poisons,
waste, and toxins
• Helps cell process lipids and
carbohydrates
• ER network (rough & smooth) connects
nucleus and cell membrane
Golgi Body
• Modifies, packages, and secretes cell
products
• Consists of flattened stacks of cisternae
• Receives products made by the ER
Lysosomes
• Contain hydrolytic enzymes to digest
materials for the cell
• Surrounded by a single membrane
• Formed from ends of Golgi body that
pinch off
• Not found in plant cells
Mitochondria
• Site of cellular respiration
• Energy (ATP - adenosine
triphosphate) is made
• Have their own DNA
• Inner membrane is folded (cristae)
Chloroplast
• Type of plastid (pigment containing
organelle)
• Stacked inner membranes called
thylakoids used to trap sunlight for
photosynthesis
• Contain chlorophyll (green)
• Have their own DNA
• Found in plants, seaweed, and, algae
• Other plastids can be red, orange, and
Vacuole
• Largest organelle in plant cells
• Hold water and help cell keep its
shape (wilt)
• Storage area for water, proteins, ions,
and glucose
• Animal vacuoles are smaller and used
for digestion
Cytoskeleton
• Helps cell maintain shape
• Helps move organelles around the cell
(tracks)
• Types:
• Microfilaments
• Microtubules
Centrioles
• Made of microtubules
• Assist in cell division (mitosis)
• Not found in plant cells
Cilia & Flagella
• Cilia - hair-like projections on a cell
made of bundles of microtubules
• Flagella - whip-like tails of microtubules
• Both help with cell movement
Cell Wall
• Non-living protective layer around plant,
fungal, and bacterial cells
• Plant cell walls are made of cellulose
Multicellular
Organization
• Cells are specialized for their functions
• Levels of organization:
• Cell
• Tissue
• Organ
• Organ System
• Organism