cells - the living units (exam 1) Flashcards
what are the three parts of the cell theory
1.) structural/functional unit 2.) all life is made of cells 3.) cells come from preexisting cells
what are the 3 variabilities to cells
size, shape, and function
what are the 3 structures of cells
membrane, cytoplasm nucleus
where does most of the weight of the membrane come from
proteins
what is an integral protein
a protein that goes all the way through the membrane
what is a peripheral protein
on the edge of the membrane
what are the functions of proteins in the membrane (7)
transport, receptor, attachment, enzyme, joining cells, recognition
what do glycoproteins do
attach to proteins
what do glycolipids do
attach to fats
what is the cell’s outer surface called
glycocalyx
what is a tight cell junction
the fusion of two cell membrane proteins to prevent movement between cells (prevents things from getting in between the cells)
what do desmosomes do
fuse protein plates together/hold cells together
how do skin cells shed
the breaking down of desmosomes
what are desmosomes made of
linker proteins
what is a gap junction
a large group of channels that line with adjacent cells to electrochemically couple cells
what are microvilli and what do they do
finger-like projections that act to increase surface area
what do cilia do
provide motion in order to move mucus
describe a selectively permeable barrier
a barrier that only allows certain things to get through
describe passive mechanisms
not using energy to cross the membrane
what is filtration
using hydrostatic pressure (fluid pressure) to move molecules
what is diffusion
the movement of molecules from an area of higher concentration to lower concentration
what does the kinetic energy of molecules mean
molecules are in constant motion
what are the factors that affect the rate of diffusion (4)
temperature, concentration gradient, solubility, molecular size/weight
how does temperature effect that rate of diffusion
higher temperature –> more kinetic energy –> faster diffusion