Module 3: Cellular Level of Organization Flashcards
Regions of a cell (3)
Plasma membrane (aka cell membrane)
Cytoplasm
Nucleus
Phospholipid bilayer
Phosphate heads, proteins, carbs and cholesterol molecules scattered within bilayer
Phosphate layer is hydrophilic
Phosphate “tails” are hydrophobic
Protein molecules
capable of moving from one side of membrane to the other
provide structural support
Provide channels for water and other substances to enter the cell
Act as receptors for hormones and enzymes
Carbohydrates
Glycoproteins (sugar “glycocalyx” and protein) act as identification markers
Cholesterol
20% of plasma membrane
Provides stiffness for membrane
Plasma Membrane
Composed of the phospholipid bilayer
Separates extracellular and intracellular material
Selective permeability
Cytoplasm
supports organelles and inclusions
Cytosol
fluid part of cytoplasm
Organelles
Mitochondria Ribosomes Rough and smooth endoplasmic reticulum Golgi apparatus Lysosomes Peroxisomes Cytoskeleton Centrosome and centrioles Cilia Flagella Nucleus
Mitochondria
“power plant” of cell
Shaped like sausages
Convert energy in nutrients to ATP
Have their own DNA and RNA
Ribosomes
Synthesize proteins
Attached to endoplasmic reticulum or “free” in cytoplasm
Rough Endoplasmic reticulum
Contains ribosomes
Smooth endoplasmic reticulum
Synthesize steroids
No ribosomes
Golgi apparatus
“traffic director” of proteins
Looks like stack of plates
Packages protein for delivery inside or outside the cell
Lysosomes
“housekeepers” of the cell
Sacs that bud off golgi complex
Powerful enzymes “eat” worn out cell parts, dead cells, bacteria
Peroxisomes
Digest normal toxic by-products of cellular metabolism
Cytoskeleton
composed of proteins
provides intracellular shape and support
Centrioles
Pair of rod-shaped structures
Separate chromosomes during mitosis
Cilia
Hairs across cell membrane (outside of cell)
Flagella
Provides movement of an entire cell
Inclusions
non-functioning units that appear and disappear
-stored nutrients
Nucleus
“captain of the ship”
Surrounded by double layer membrane (nuclear envelope) with pores
Filled with nucleoplasm that dissolves salts, nutrients, etc
Contains nucleolus
Stores genetic info
Nucleolus
Inside the nucleus, makes ribosomes and chromatin
Chromatin
a complex network of threads containing DNA
forms into chromosomes when a cell is about to divide
Passive transportation
no ATP required
includes simple diffusion, facilitated diffusion, osmosis and filtration
Active transportation
ATP required
Includes active transport pumps, endocytosis and exocytosis
Endocytosis
Transporting bulk material into a cell
Particles surrounded by plasma membrane, sac is formed and then is pulled inside the cell
Includes: phagocytosis, pinocytosis, receptor mediated endocytosis
Phagocytosis
“cell eating”
Pinocytosis
“cell drinking”
Receptor mediated endocytosis
specific membrane receptor binds with specific substance and then brought into cell
Exocytosis
Vesicles moved from Golgi apparatus into plasma membrane.
Vesicle membrane fuses with plasma membrane, then ruptures, letting go of the product to the outside of the cell
Vesicles
sacs of “outgoing” product
packaged by Golgi apparatus
