study it all Flashcards
What are the principles of the cell theory?
All living organisms are composed of one of more cells. Cells are the basic unit of structure and organization of all living organisms. Cells arise only from previously existing cells, with cells passing copies of their genetic material on to their daughter cells.
What are the differences between a prokaryotic cell and a eukaryotic cell?
Eukaryotic cells contain a nucleus and other organelles. Prokaryotic cells are cells without a nucleus or other membrane-bound organelles.
What is a cell?
A cell is the basic structural and functional unit of all living organisms.
What is cell theory?
The cell theory is one of the fundamental ideas of modern biology.
What is a plasma membrane?
A plasma membrane is a special boundary that helps control what enters and leaves the cell.
What is an organelle?
Organelles are specialized structures that perform specific cell functions.
What is a nucleus?
The nucleus is the distinct central organelle that contains the cell’s genetic material.
How does a cell’s plasma membrane function?
The plasma membrane forms a thin, flexible boundary between a cell and its environment.
What are the roles of proteins, carbohydrates, and cholesterol in the plasma membrane?
Cholesterol is non-polar; prevents the fatty acid tails of the phospholipid bilayer from sticking together. Cholesterol contributes to the fluidity of the membrane. Carbohydrates define the cell’s characteristics and help cells identify chemical signals.
What is selective permeability?
They allow some substances to pass through while keeping others out.
What is the phospholipid bilayer?
Two layers of phospholipids are arranged to allow the membrane to exist in a watery environment.
What is the fluid mosaic model?
The fluid mosaic model describes the phospholipids in the bilayer as a “sea” in which other components can float and move around.
What is the prosses of diffusion?
Diffusion is the net movement of particles from an area of high concentration to an area of lower concentration. Additional energy is not required for diffusion because the particles are already in motion.
What is the prosses of facilitated diffusion?
Facilitated diffusion uses transport proteins to move ions and small molecules across the plasma membrane. Diffusion and facilitated diffusion are types of passive transport – they require no additional energy.
What is the prosses of active transport?
The movement of particles across the cell membrane, against the concentration gradient, requires energy and is called active transport.
Define the dynamic equilibrium.
When diffusion occurs over a long enough time, concentrations become uniform, and the solution will reach dynamic equilibrium.
Define osmosis.
Osmosis is the diffusion of water across a selectively permeable membrane.
An isotonic solution is …
An isotonic solution has the same concentration of water and solutes as the cell’s cytoplasm. Water still moves through the membrane, but it enters and leaves simultaneously.
A hypotonic solution is …
A hypotonic solution has a lower concentration of solutes than the cell’s cytoplasm.
cytoplasm
The environment enclosed by the plasma membrane is a semifluid material called cytoplasm.
cytoskeleton
The cytoskeleton is a supporting network of long, thin protein fibers that form a framework for the cell and proved an anchor for the organelles.
ribosome
Ribosomes are organelles that manufacture proteins.
endoplasmic reticulum
The endoplasmic reticulum (ER) is a membrane system of folded sacs and interconnected channels that serves as the site for protein and lipid synthesis.
Golgi apparatus
The Golgi apparatus is a flattened stack of membranes that modifies, sorts, and packages proteins.
