Chapter 3 Cells Flashcards
Name the three main parts of a cell
plasma membrane
cytoplasm
nucleus
Describe the plasma membrane in general terms
is a protective layer and communication center for the cell between its internal and external environment. It regulates the flow of materials in and out.
Define cytoplasm
is the space between the plasma membrane and the nucleus
what is contained in the cytoplasm
cytosol and organelles
what is cytosol and what is it also referred to
cytosol is the liquid in the cytoplasm that contains the organelles. it is also called intracellular fluid
define a nucleus and its functions
the largest organelle in the cell
is the control center
contains genetic material which controls cell structure and activities
what is the cell membrane made of
lipids and proteins
what kinds of lipids make up the plasma membrane
phospholipids
describe what phospholipids look
they are shaped like a lollipop
what are phospholipds made of
phosphates and lipds
what is water loving
hydrophilic
what is water fearing
hydrophobic
what does it mean for something to be polar and non polar
polar is hydrophilic
non polar is hydrophobic
explain the structore of a phospholipid
polarity and water
shaped like a lollip pop with a round top on the outside of the plasma membrane and a stick bottom on the inside of the plasma membrane
polar and water loving part part is the phosphate - faces the exterior of the cell
non polar and the water fearing part is the lipids - faces the interior of the cell
explain selective permeability
the plasma membrane allows some substances to move in and out of the cell but restricts others
what are two main types of proteins
Integral
Peripheral
describe an integral protein
an integral protein passes through or embeds itself in the cell membrane
describe a peripheral protein
peripheral protein stays on the outside of the plasma membrane
what are some of the functions of proteins
carriers
receptors
enzymes
cell identity
ion channels
explain what a carrier protein does
a carrier protein is an integral protein that passes through the plasma membrane to allow passages for substances
explain a cell identity marker protein
can help cells identify its own kind and detect foreigners
explain a receptor protein
receptor proteins are integral and receives signals and delivers them to the cell to cause a cellular response
explain an enzyme protein
an enzyme protein speeds up a chemical process
what is the basic framework of the plasma membrane called
lipid bilayer
what does the lipid bilayer contain
two, tail-to-tail layers that make up three types of molecules
what are the three types of molecules that make up the lipid bilayer
phospholipids
cholesterol
glycolipids
what makes up a glycolipid
a lipid attached to a carbohydrate
what does an ion channel do and what kind of protein is it
integral protein that creates a channel or passage for certain substances
what kind of fluid makes up about two-thirds of the fluid in the human body
intracellular fluid
what is the abbreviation for intracellular fluid
ICF
is the intracellular fluid of the cell also cytosol
yes
what is fluid outside of the body cells called
extracellular fluid
what is the abbreviation for extracellular fluid
ECF
what is the ECF in the microscopic spaces between the cells of tissues
interstitial fluid
what is the ECF in blood vessels called
blood plasma
what is the ECF in lymphatic vessels called
lymph
what is the ECF around the brain and spinal cord called
cerebrospinal fluid
what is the material dissolved in a fluid called
solute
what is the fluid in which the solute is dissolved called?
solvent
what is the amount of solute in a solution called
concentration
what is the concentration gradient
it is the difference in concentration between areas
what is the electrochemical gradient
concentration of ions on one side of the plasma is different than the other side
explain the difference between active and passive transport
passive transport is when substances pass through the gradient using their own kinetic energy
active transport is when substances pass through the gradient with cellular energy like ATP
name two types of passive transport
diffusion
osmosis
name two types of diffusion
simple
facilitated
define diffusion
when substances passively move through the plasma membrane using their own energy
they move from an area of high concentration to an area of low concentration
define simple diffusion
substances pass through the cell membrane freely and on their own
define facilitated diffusion
an integral membrane protein assists with the substance crossing the plasma membrane
energy is not required but a carrier or channel is
explain osmosis
the transportation of water through a selectively permeable membrane
water moves from a high concentration area to a lower concentration area
or it moves from a low solute area to a high solute area
is osmosis an active or passive process
passive
what two places do water molecules pass through the plasma membrane
the lipid bilayer
integral member channels designated for water transport
explain osmotic pressure
when a solution has particles that cannot pass through the membrane, the osmotic pressure increases. the pressure depends on the concentration of the solution. the higher the concentration, the higher the osmotic pressure and vice versa.
do cells shrink or increase in size due to water loss or gain, why?
no, because cytosol and interstitial fluid have the same osmotic pressure
explain an isotonic solution
any solution where cells keep their normal shape and volume. the concentration of the solutes is the same inside and outside the cell.
explain hyptonic solution
a hyptonic environment exists when the concentration of solutes is different on one side of the cell vs the other.
provide an example of hypotonic with red blood cells
if red blood cells are placed in a hypotonic solution and the solute concentration is higher inside the cell than outside the cell, the red blood cell will take in water faster than it releases water, and this will cause it to burst
what is it called when a red blood cells bursts
hemolysis
explain a hypertonic solution
when the solute concentration is higher outside the red blood cell than inside the cytoplasm, water will leave the red blood cell faster than it comes in, and this will cause the red blood cell to shrink
what is the shrinkage of red blood cells called
crenation
Define Active Transport
the process by which substances pass through the plasma membrane against the concentration gradient using cellular energy. They go from low concentration to high concentration ares.
explain what a pump is in active transport
a carrier protein that changes shape as it carries substances across the cellular membrane against its concentration gradient
how does the pump change shape for transport
uses energy from ATP
what is the most important active transport pump
sodium potassium pump
how does the potassium sodium pump operate
does it constantly operate?
it maintains a low concentration of sodium in the cytosol by pumping sodium against the gradient into extracellular fluid
simultaneously, it pumps potassium ions into cells against the potassium concentration gradient
it constantly operates
what is the chemical name for sodium
Na+
what is the chemical name for potassium
K+
Why does the Na+-K+ pump constantly operate
because Na+ and K+ slowly leak back past the cell membrane
what are the two reasons it is crucial that the Na+-K+ pump constantly operate
to maintain the proper balance of Na+ and K+ inside and outside the cell for osmotic balance
and for some cells to be able to generate electrial signals
explain how the sodium-potassium pump operates
Three sodium (Na+) ions bind to the pump protein
When the Na+ binds, the protein is triggered to split ATP into ADP plus a phosphate group, which also binds to the protein. This chemical reaction changes the shape of the protein expelling the three Na+ ions into the extracellular fluid.
The changed shape of the protein is now ready to receive two K+ ions from the extracellular fluid. The K+ ions bind to the newly shaped protein.
When this happens, the phosphate group is released and the pump returns to its original shape
As the pump returns to its original shape, it releases the K+ into the cytosol
what is a vesicle
a small round sac that transports substances in and out of the cell
what does movement of the vesicles require
energy from ATP
is the movement of the vesicle and active or passive transport process
active
what are the two main types of transport in vesicles
endocytosis
exocytosis
what is endocytosis
when substances are moved into the cell through a vesicle
what is exocytosis
when substances are moved out of a cell via a vesicle
how is a vesicle formed
substances are brough into the vesicle, which is embedded in the cell membrane, and the vesicle then buds off and forms a sac around the substance
what are the two types of endocytosis
phagocytosis
bulk phase endocytosis
explain phagocytosis
what is it also called and what is the process
also called cell eating
eats large solid particles like bacteria, viruses, or dead cells
particle binds to a plasma membrane receptor, which causes the cell to extend pseudopods
two or more psuedopods surround the particle and portions fuse to form vesicle that enters the cytoplasm
The phagosome fuses with one or more lysosomes, breaks down the material
Undigested material may remain indefinitely in the cell or be excreted by the cell
what are pseudopods
projections from the cell membrane and cytoplasm
where is the only place phagocytosis can occur
in phagocytes
what are phagocytes
cells specifically designed to engulf and break down bacteria or other foreign substances
what is phagocytosis critical for?
protecting the body against disease
what is bulk phase endocytosis also called
pinocytosis
how does pinocytosis work
It is cell drinking
takes up tiny droplets of extracellular fluid
it takes in any and all solutes dissolved in the extracellular fluid
the plasma membrane folds inward and forms a vesicle containing a droplet of extracellular fluid
the vesicle detaches or pinches off from the plasma membrane and enters the cytosol
Vesicle fuses with a lysosome where enzymes break down and engulf the solutes
what happens to the amino acids and fatty acids that are a result of pinocytosis
they leave the lysosome to be used elsewhere in the body
what does exocytosis do
brings materials out of the cell
what two types of cells are particularly important in exocytosis
cells that release digestive enzymes, hormones, mucus, or other secretions
nerve cells that release neurotransmitters
how does exocytosis work
membrane enclosed vesicles form inside the cell, fuse with the plasma membrane and release their contents into the extracellular fluid
what does the nucleus consist of and what does it do
nuclear envlope with pores, nucleoli, and chromatin (or chromosomes)
containes genes, which control cellular structure and direct most cellular activities
produces ribosomes in nucleoli
what is the nuclear envelope
a double membrane that separates the nucleus from the cytoplasm
what do nuclear pores do
control the movement of substances in and out of the nucleus
what is the nucleoli made of and what happens in the nucleoli
protein, DNA, and RNA
ribosomes are made
