Chapter 3--> Cell Structure and Functions Flashcards
What is cell theory?
A scientific theory first formulated in the mid-nineteenth century, that organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells
What are prokaryotic cells?
Single-celled organism that lacks a nucleus and membrane-bound organelles
What are eukaryotic cells?
A nucleus enclosed within the nuclear membrane and form large and complex organisms
What are organelles?
Subcellular structure that has one or more specific jobs to perform in the cell
What are organelles?
Subcellular structure that has one or more specific jobs to perform in the cell
What are used to look at small cell structures?
Microscope
What in the nucleus’ job in the cell
The nucleus serves both as the repository of genetic information and as the cell’s control center
What takes place within the nucleus?
DNA replication, transcription, and RNA processing
Where does the final stage of gene production take place?
The Cytoplasm
What are Ribosomes?
A minute particle consisting of RNA and associated proteins found in large numbers
Where are Ribosomes found?
The Cytoplasm
What does ER stand for in the cell?
Endoplasmic Reticulum
What does the ER do?
Serves many roles in the cell including calcium storage, protein synthesis and lipid metabolism
What is a rough ER?
An extensive organelle composed of greatly convoluted but flattish sealed sacs, which are contiguous with the nuclear membrane
What is a smooth ER?
Synthesizes lipids, phospholipids as in plasma membranes, and steroids
What is the Mitochondria?
Mitochondria are membrane-bound cell organelles that generate most of the chemical energy needed to power the cell’s biochemical reactions
What are lysosomes?
Membrane-enclosed organelles that contain an array of enzymes capable of breaking down all types of biological polymers—proteins, nucleic acids, carbohydrates, and lipids
What is the golgi apparatus?
Responsible for transporting, modifying, and packaging proteins and lipids into vesicles for delivery
What is the cell membrane?
Biological membrane that separates and protects the interior of all cells from the outside environment
What is the cell wall?
A rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria
What is passive transport?
A movement of biochemicals and other atomic or molecular substances across membranes that does not require an input of chemical energy
What is diffusion?
A physical process that refers to the net movement of molecules from a region of high concentration to one of lower concentration
What is osmosis?
The net movement of water across a semipermeable membrane
What is a semipermeable membrane
A type of biological or synthetic, polymeric membrane that will allow certain molecules or ions to pass through it by osmosis
How does passive transport work?
Substances simply move from an area of higher concentration to an area of lower concentration, which does not require the input of energy. Concentration gradient, size of the particles that are diffusing, and temperature of the system affect the rate of diffusion
What is permeability?
The passage of molecules through a biological membrane or a barrier
What is selective permeability?
Substances cannot cross the barrier indiscriminately
What part of the cell have selective permeability?
The cell membrane
How does selective permeability work?
Its ability to differentiate between different types of molecules, only allowing some molecules through while blocking others
What are phospholipids?
A lipid containing a phosphate group in its molecule
What are examples of phospholipids?
Phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin
Where are phospholipids found?
The plasma membrane
What is a concentration gradient?
Occurs when the concentration of particles is higher in one area than another
How does the concentration gradient work?
Occurs when the concentration of particles is higher in one area than another.
