Chapter 3: Cells Flashcards
What is the molecular composition of the plasma membrane of the cell?
Two layers of phosphate-containing lipid molecules called phospholipids form a fluid framework for the plasma membrane. Another kind of lipid molecule called cholesterol is also a component of the plasma membrane.
What is cytoplasm?
Cytoplasm is the internal living material of cells. It fills the space between the plasma membrane and the nucleus.
What is contained within the cytoplasm?
The cytoplasm contains small threadlike structures that interconnect to form a “cell skeleton” or cytoskeleton. The cytoskeleton organizes and supports a group of small structures collectively called organelles.
What are the primary organelles of the cell?
Ribosomes, Endoplasmic Reticulum (ER), Golgi Apparatus, Mitochondria, Lysosomes, Centrosome
What are the functions of these organelles?
1) Ribosomes synthesize proteins; a cell’s “protein factories”; 2) Endoplasmic Reticulum (which is divided into rough and smooth ER): Rough ER receives and transports synthesized proteins (from ribosomes); smooth ER synthesizes lipids and certain carbohydrates; 3) Golgi apparatus: Chemically processes, then packages substances from the ER; 4) Mitochondria: ATP synthesis; a cell’s “power plants” or “battery chargers”; 5) Lysosomes: A cell’s “digestive bag,” it breaks apart large molecules; 6) Centrosome: Organizes microtubules of the cytoskeleton
Which two kinds of cell structures contain DNA?
Nucleus and Mitochondria
What is the difference between a passive transport process and an active transport process?
A passive transport process does not require cell energy (ATP) whereas an active transport process does require cell energy (ATP).
Briefly explain the Diffusion passive transport process.
The process by which substances scatter themselves evenly throughout an available space.
Briefly explain the Osmosis passive transport process.
It’s the passive moment of water molecules through water channels in a selectively permeable membrane when some of the solute cannot cross the membrane. Alternately, it’s the process of water moving from an area of high concentration to low concentration. Examples of this process include adding a grape to water, our skin in water when we take a shower, plants absorbing water, etc.
Briefly explain the Dialysis passive transport process.
Some solutes move across a semipermeable membrane by diffusion and other solutes do not. This results in an uneven distribution of various solutes.
Briefly explain the Filtration passive transport process.
The movement of water and solutes through a membrane as a result of a pushing force that is greater on one side of the membrane than on the other side. Wastes are filtered out of the blood into the kidney tubules because of a difference in hydrostatic pressure.
How does an ion pump work?
The ion pump uses energy from ATP to actively move ions across cell membranes against their concentration gradients.
How do phagocytosis and pinocytosis differ?
In Phagocytosis a cells engulfs and literally eats large particles whereas in Pinocytosis a cell “drinks” fluids or dissolved substances by trapping them in a pocket of plasma membrane that pinches off into the cell to form a vesicle.
How do genes determine the structure and function of the body?
The genetic code, which is contained in segments of the DNA molecules that are called genes, ultimately determines the structure and function of all cells
Where is genetic information stored in the cell?
Chromosomes, which are composed largely of DNA, contain the information needed to make all the proteins of the cells. Contained in segments of the DNA molecules that are called genes. Most of the DNA, with its genetic code that dictates instructions for protein synthesis, is contained in the nucleus of the cell.
