Chapter 3 Flashcards
(79 cards)
what is cell theory and its different aspects?
cell theory says that 1. cells are the basic structural and functional unit of life, 2. cells come from pre-existing cells (half cells from each parent), 3. cells carry out physiological function, 4. each maintain its own homeostasis
what are the two basic types of cells found in the body?
sex cells: reproductive cells somatic cells: all other cells in the body; soma=body
what are the major divisions of a cell?
the plasma membrane, cytoplasm, and nucleus
plasma membrane
the phospholipid bilayer that separates the extracellular fluid from the intracellular fluid.
this regulates exchange with the environment
cytoplasm
everything inside the plasma membrane and outside the nucleus including cytosol, organelles, insoluble material and stored nutrients
nucleus
the control center of a cell; determines the structure and functions of the cell by dictating what proteins are made
what is a gene?
segments of DNA that encode for specific protein
cytosol
fluid part of the cytoplasm and has more potassium than the extracellular fluid but less sodium; stores small amounts of carbs and proteins
phospholipid bilayer
hydrophilic heads and hydrophobic tails with cholesterol to strengthen
6 plasma membrane proteins
transport, receptors for signal transduction, attachment to the cytoskeleton and extracellular matrix, enzymatic activity, intercellular joining, cell-cell recognition
membrane carbohydrates
sticks out of the plasma membrane to form a sticky outer layer called the glycocalyx for lubrication, protection, anchoring and locomotion, binding, cell recognition
how do cells regulate internal environment?
the membrane is semi-permeable. this allows cells to regulate internal environment
passive process
does not require ATP; simple and facilitated diffusion, osmosis, filtration
active processes
does require ATP; active transport and vesicular transport (exocytosis and endocytosis)-phagocytosis and pinocytosis
simple diffusion
constant movement for fat soluble and nonpolar molecules from high to low concentration; the bigger the difference, the steeper the gradient.
facilitated diffusion
helps water soluble and polar molecules move from high to low concentration through a protein channel, ex: alcohol, fatty acids, oxygen, water
osmosis
diffusion of water across membrane from high to low concentration
tonicity
way to compare relative solute concentrations in two solutions
hypertonic:
water moves out of the cell because of less water, more salt outside the cell; too much water in the cell and it will lyse (burst)
hypotonic
water flows into the cell because there is more water and less salt outside the cell; the cell would crenate (shrink)
isotonic
no osmotic flow occurs, there is equilibrium betweem the water and solute inside and outside of the cell
active transport
energy is required to transport a substance across the cell membrane; uses ATP and carriers proteins called pumps; pump against concentration gradients
vesicular transport
bulk movement of solutes in or out of the cell using vesicles; requires ATP
endocytosis
movement of molecules into the cell
