Cell membranes Flashcards
what penetrates the hydrophobic core of the lipid bilayer and the hydrophobic regions of an integral protein consist of one or more stretches of non polar amino acids
integeral proteins
these are not embedded in the lipid bilayer at all, they are appendages loosely bound to the surfaece of the membrane
peripheral proteins
what is it called when membrane proteins of adjacent cells hook toghether in various junctions, such as gap junctions or tight junctions
intracellular joining
whats function is by having a hydrophobic channel that certain molecules or atomic ions use as a tunnel through the membrane
channel proteins
the passage of water molecules through the membrane in certain cells is generally facilitated by channel proteins known as ______
aquaporins
the diffusion oa a substance across a biological membrane is called ______ _______ because the cell does not have to expend energy to make it happen
passive transport
is a cell with out a wall is immersed in an environment that is _____ to the cell and there will be no net movement of water across the plasma membrane
isotonic
if a solution is _______ to the cell the solution has more solutes than the cell and the cell will lose water to its environment and shrivel and die
hypertonic
is a solution is ___ to the cell the solution has a lower solute concentration than the cell so therefor water will enter the cell and cause it to swell and potentially burst. lysis
hypotonic
what is the name given to the control of water balance
osmoregulation
another group of channes are called _____ channels and many of these function as gated channels, a stimulus causes them to open or close
ion
____ ____ is when the cell must expend energy because the molecule is being pumped across the membrane down against the concentration gradient.
active transport
____ ____ is the charge difference between a cells cytoplasm and the extracellular fluid, due to the differential distribution of ions.
membrane potential
a transport protein that generates voltage across a membrane is called a _____ _____
electrogenic pump
a single ATP powered pump that transports a specific solute can directly drive the active transport of several other solutes in a mechanism called ______
co-transport
_______ is when the cell secreted macromolecules by the fusion of vesicles with the plasma membrane
exocytosis
in _____ the cell takes in macromolecules and particular matter by forming new vesicles from the plasma membrane
endocytosis
a ____ is the general term for any specific molecule that binds specifically to a receptor site of another molecule
lingand
what is the function of the cell membrane
seperates the cell from the outside environment and controls what enters and leaves the cell.
what causes the cell membrane to be partially permeable
the phospholipid bilayer and its components
what do proteins and fats do in the cell membrane
allow receptors to bind and provide structural integrity
what is the function of the cytoplasm
holds everything inside the cell and outside the nucleus. maunly mase up of fluids. keeps everything in the cell in place.
what is the function of the nucleus
controlls everything that happens in the cell
regulates DNA and RNA actions
it is a membrane bound organelle that protects the DNA
what is the function of the nuclear envelope that surrounds the nucleus
protects the nucleus. there are ribosomes present to help with protein synthesis.
the envelope has nuclear pores that help to control what can enter or leave the nucleus.
it is made with a double layer of lipids which make it semi-permeable
what is the fucntion of the nucleolus
this is where ribosomal RNA is made
what is the fucntion of the rough endoplasmic recticulum
contains ribosomes and helps with protein synthesis. processes and folds proteins
what is the function of the smooth endoplasmic recticulum
synthesis and processing of lipids, prominent in drug metabolism . more tubular than RER
what is the fucntion of lysozomes
its a vesicle containing digestive enzymes ot breakdown worn out cells or foreign objects.
it is a membrane bound organelle
what is the fucntion of the mitochondria
membrane bound organelle used for aerobic respiration. involves in the synthesis of ATP. contains DNA, and the folding of the internal membrane increases the surface area for respiration to occur
what is the fucntion of the golgi apparatus
sorts and processes molecules that need to be transported out of the cell and around the body
It can change a protein . addition of other molecules to change the shape and the function.
Processes proteins, cleavage of peptides to produce activated proteins
Sorting and isolation of proteins.
what is the structure of the nucleus entail
. Nucleolus. Chromatins, nuclear envelope. Nuclear lamina (part of the nuclear envelope), nucleoplasm,
Nucleoplasm is the amorphous fluid (no distinct shape). Contains components such as proteins, rna ribonucleoproteins and small molecules.
Plus fibrous chromatin (50% protein and 50% dna) which occupies about 80-90% of the nuclear volume.
what is the overall function of the SER and the RER
detoxification of drugs
translocation of proteins
glycosylation of proteins- adding sugars to other molecules and proteins
assembly of lipid bi-layers
what is cellular digestion?
lysosomes fuse with the food vacuole, polymers are digested into monomers. this is passed to the cytosol to become the nutrients of the cell.
