Cells Flashcards
What are the cells composed of four elements?
Carbon
Hydrogen
Oxygen
Nitrogen
How many % of water are cells about?
60%
Transparent barrier for cell contents
Plasma Membrane
Contains cell contents
Plasma Membrane
Separates cell contents from surrounding environment
Plasma Membrane
arrange “tail to tail”
two layers of phospholipids
scattered among the phospholipids
cholesterol and proteins
Sugar groups may be attached to the phospholipids
forming glycolipids
Water loving
Hydrophilic
Water fearing
Hydrophobic
polar “heads” are oriented on the inner and outer surfaces of the membrane
hydrophilic
non-polar tails form center (interior) of the membrane
Hydrophobic
Impermeable junctions
Tight junctions
Bind cells together into leakproof sheets
Tight junctions
Plasma membranes fuse like a zipper to prevent substances from passing through extra cellular space between cells
Tight junctions
Anchoring junctions, like rivets
prevent cells from being pulled apart as a result of mechanical stress
Desmosomes
Created by buttonlike thickenings of adjacent plasma membranes
Desmosomes
To allow communication
found in the heart and between embryonic cells
neighboring cells are connected by hollow cylinders composed of proteins called (Connexons)
Gap junction
Control center of the cells
Nucleus
Contains genetic material known as deoxyribonucleic acid , or DNA
Nucleus
Needed for building proteins
DNA
necessary for cell reproduction
DNA
Three regions of nucleus
Nuclear envelope (membrane)
Nucleolus
Chromatin
Sites of ribosome assembly
Nucleolus
The cellular material outside the nucleus and inside the plasma membrance
Cytoplasm
Site of most cellular activities
Cytoplasm
Includes cytosol, inclusions and organelles
Cytoplasm
Fluid that suspends other elements and contains nutrients
Cytosol
Chemical substances, such as stored nutrients or cell products, that float in cytosol
Inclusions
Metabolic machinery of the cell that perform functions for the cell
Organelles
Powerhouses of the cells
Mitochondria
consist of a double membrane with cristae on the inner membrane
Mitochondrial wall
Carry out reactions in which oxygen is used to break down food into ATP molecules
Mitochondria
Made of protein and ribosomal RNA
Ribosomes
Sites of protein synthesis in the cell
Ribosomes
Where ribosomes located
Free in the cytoplasma
Attached to the rough endoplasmic reticulum
Fluid-filled tunnels (or canals) that carry substances within the cell
Endoplasmic reticulum
Continuous with the nuclear membrane
ER
Two types of ER
Rough
Smooth
Studded with ribosomes
Rough ER
Transport vesicles move proteins within cell
Rough ER
Synthesizes proteins
Rough ER
Abundant in cells that make and export proteins
Rough ER
Two basic methods of transport
Passive processes
Active Processes
substances are transported across the membrane without any input from the cells
Passive processes
Cell provides the metabolic energy to drive the transport process
Active processes
