Cells Flashcards
What are cells?
The basic unit of structure and function of living things
What are the 3 components of cell theory?
1) cells are the basic structural and functional units of living things
2) all living thin are made up of cells
3) cells arise from preexisting cells
What are 3 characteristics shared by all cells?
1) they have DNA at some point
2) they have a plasma membrane
3) they have cytoplasm
What are the two types of cells that comprise livings?
Prokaryotic and Eukaryotic cells
What are the differences between these two cell types
Size- prokaryotes are small eukaryotes are large.
Location of DNA- prokaryotes are in the nuleoid, eukaryotes
are in nucleus
Membrane bound organelles-
Prokaryotes have none orvery few, eukaryotes have many
Organization of genetic material- prokaryotes have circular DNA, eukaryotes have linear DNA
What comprises the plasma membrane?
A lipid bilayer that contains cholesterol and proteins
What are phospholipids?
Molecules of fat with phosphate groups on the ends
What makes phospholipids so unique?
The fat end of the phospholipid is hydrophobic and the phosphate end is hydrophilic
Why is a plasma membrane described as a bilayer?
Phospholipids are lined up double so that the fathoms are facing each other and the phosphate ends are out word
What is the fluid mosaic model of the cell membrane?
Plasma membrane is fluid made up of many components molecules are mobile and they move around in a sea of lipids
What other molecules are a part of a plasma membrane?
Proteins
What are the three functions of membrane proteins?
Transport -to move molecules across the membrane
Enzymes-speed up chemical reactions
Receptors- bind hormones, other molecules,
trigger changes in the cell
What are the three types of membrane Junctions found in cells?
Tight junctions fuse adjacent cells impermeable They are found in the lining of the digestive tract
Desmosomes- anchor adjacent cells They are found in the skin and heart
Gap Junctions allow communication between cells They are found in the heart, smooth muscle, and cardiac muscle
How do molecules move across a plasma membrane?
Passive processes, active processes, vesicular transport
What are the passive processes by which things move across membranes?
Diffusion, simple diffusion, facilitated diffusion and osmosis
What are the active processes by which things move across the membranes?
Active transport, vesicular transport
What is simple diffusion?
Molecules diffuse directly across the plasma membrane
Does simple diffusion require energy in order to move molecules?
No
How does water get across a plasma membrane?
Osmosis
What is osmosis?
Movement of a solvent across a selectively permeable membrane from regions of high solvent concentration to regions of low solvent concentration usually water
What is a solute?
Dissolved particles
What is a solvent?
Dissolving substance usually molecules in greatest amounts
What is tonicity?
Dissolve particle concentration in a solution with respect to some other solution
What does it mean when cell contents are described as being isotonic?
Equal concentrations of solutes on either side of the membrane
What does it mean when a cell contents are described as being hypertonic?
Higher concentration of solutes on one side of the membrane
What does it mean when cell contents are described as being hypotonic?
Lower concentration of solutes on one side of the membrane
What is active transport?
Movement of solutes against a concentration gradient low-to-high requires carrier proteins to move molecules
Does this process of active transport require energy?
Yes
What is an example of active transport in cells?
Na+/K+ pump
What is exocytosis?
Move things from inside of the cell to outside of the cell
What is endocytosis?
Move things from outside of the cell to the inside of the cell
What are the two types of endocytosis?
Phagocytosis cell eating and pinocytosis cell drinking
Nucleus?
Contains chromatin DNA and proteins
Nucleolus?
Ribosome subunits made here one or two per cell associated with regions of DNA that make rRNA
Mitochondria?
Site of aerobic cellular respiration ATP production / energy transformation
Ribosomes?
Site of protein synthesis comprised of RNA and protein to subunits large and small
Rough endoplasmic reticulum?
Makes all proteins secreted from the cell integral membrane proteins phospholipids
Smooth endoplasmic reticulum?
Lipid metabolism cholesterol synthesis
Golgi apparatus
Stack of membranous sacs modifies and packages lipids and proteins for export from the cell the finishing touches School
Lysosome?
Dispose of bacteria and debris contain digestive enzymes garbage truck
Peroxisome?
Contains enzymes that detoxify formaldehyde and alcohol Dad’s job
Microtubules?
Cell structure and shape train tracks of the cell
Microfilaments?
Cell structure and shape train tracks of the cell
Centrosomes?
Microtubule organizing Center region of cytoplasm around centrioles
Centrioles?
9 triplets or microtubules both involved in cell division the Ziti or the churro
Cilia?
Short synchronously beating microtubules
Flagellum?
Responsible for cell movement made of long microtubules the 9 + 2 arrangement
