6 Flashcards
passive transport
passive net movement of molecules from an area of high concentration to an area of lowconcentration.
What can diffuse through the cell membrane
Small non polar substances, hydrophobic and uncharged substances
Osmosis
the passive net water molecules across cell membrane from an area of low solute concentration to an area of high solute concentration
what channel does osmosis require
aquaporins
aquaporins
type of channel protein required for osmosis to transport water across the cell membrane
why does osmosis require aquaporins
If water tried to pass the cell membrane it would not pass through as it would repel the hydrophobic tails because water is polar.
How long does osmosis happen
continues as long as there is a semi permeable membrane, however when the equilibrium is reached there is no net movement of water
Isotonic solution
same solute concentration is the same inside the cell as it is outside of the cell
Hypotonic solutio
lower solute concentration outside the cell than inside the cell
Hypertonic solution
higher solute concentration outside the cell than inside the cell
haemolysis
when Water enters an animal cell causing it to swell enough to rupture the cell membrane in of a hypotonic solute,
the cell is said to be in a state of haemolyiss or is lysed
turgid
when water enters the plant cell in hypotonic solutions and causes the vacuole to expand and to squeeze the cytoplasm against the cell wall, hence the cell is said to be turgid
Crenation
when Water moves out of the cell causing the cell to shrink and crinkle in hypertonic solutions
plasmolysis
Water moves out of the cell causing it to shrink - The cell wall maintains cell shape the cell in hypertonic solutions
what happens in isotonic solutions
In both animal cells and plant cell Water moves into and out of the cell at the same rate and no net movement in/our ofcell
what happens in Hypotonic solution
In animal cells
Water enters the cell causing it to swell enough to rupture the cell membrane, the cell is said to be lysed
In plant cells, Water enters the cell and passes into the vacuole causing vacuole swells and squeezes the cytoplasm against the cell wall the cell hence, is said to be turgid
What happens in Hypertonic solution
In animal cells, crenation-
Water moves out of the cell causing the cell to shrink and crinkle
In plant cells, the cell goes into a state of plasmolysis as water leaves the cell but the cell maintains its shape because of the cell wall
Active transport
The active net movement of a substance with the use ATP from an an area of low concentration to an area of high concentration
How does active tranposrt take place
Membrane transport proteins use energy from ATP to move molecules or ions against the concentration gradient
main source of celluar energy in active transprot and why
ATP because it powers almost all the porcesses within a cell and acts as fuel for the membrane transport proteins to pump ions against the concetration gradient
Bulk transport
Bulk transport is the movement of large particles in and out of a cell
What happens in endocytosis
endocytosis captures substances or particles by engulfing them and bringing them into the cell.
the types of endocytosis
phagocytosis and pinocytosis
Phagocytosis
endocytosis of solid substances eg. food
pinocytosis
endocytosis of liquids
common in animal cells as it brings nutrient rich extracellular fluid into cell)
membrane vesicles that hold large molecules are formed by
golgi body
Exocytosis takes place to
secrete waste from the cell
to relocate some of the substances produced in cells (e.g. hormones, mucus, milk proteins and digestive enzymes) elsewhere in the body.
differecne between passive and active trnaposrt
passive transport does not require ATP whilst active trnapsort does
Facilitated diffusion
the passive net movement of molecules across the plasma membrane through transport proteins from an area of low solute concentration to an area of high solute concentration
What do the protein molecules embedded in the plasma membrane do
allow for passive transport
these proteins are used to transport small polar substances and hydrophilic substances as they are unable to diffuse throguh the membrane by themselves
Why does facilated diffusion not use ATP
it is a type of passive transport
what proteins aid in faciliated diffusion
channel and carrier proteins
describe the passage ways of channel proteins andwhat diffuses through them
Narrow passageways through which water molecules and ion diffuse rapidly from an area of low solute concentration to an area of high soluteconcentraiton
describe what carrier proteins bind to, what they do to their shape and what they do
Bind to specific molecules on one side of the membrane, change shape and release the substance on the other side
can diffuse rapidly from a high ion concentration to a lower ion concentration.
types of passive transport
facilitated diffusion
osmosis
simple diffusion
Types of active transport
active transport
bulk transport-endocytosis and exocytosis
What soultion has no net movement
istonic soultion
what istonic solution does a plantcell have
flaccid
What is the difference between simple and facilated diffusion
Their identical EXCEPT facilicated diffusion requires channel and carrier proteins
What is a type of facilated diffusion
osmosis as it requires a channel protein
why does active transport require ATP
active transport goes against the concentration gradient
does not need to maintain equilbirum
requires channel and carrier proteins
What organelle does active transport require
mitochondria
Explain how the cell size changes in endocyotosis and excoytosis
in endocytosis the cell size decreases
in exocytosis the cell size increases
Types of endocytosis
Phagocytosis and pinocytosis
what happens in phagocytosis and pinocytosis
in phagocytosis a solid is engulfed, whilts in pinocytosis a liquid is engulfed
simple diffusion
movement of molecuels frm an area of high concetraiton to anrea of low concentration through a semi permable membrnae
what are examples of bulk transport
endo and exocyostis
what are examples of bulk transport
endo and exocyostis
process of endocytsosis
1.Folding of the plasma membrane
2.Vesicle forms around molecules being transported
3.Contents released within the cell
process of exocytosis
1.Molecules enclosed in a vesicle
2.Vesicle fuses with the plasma membrane
3.Contents released
how do hydrobic molecules move through the plasma membrnae
diffusion
hydropholic head
protects the hydrobic tails from exposure extracelluar and intercelluar fluid
makes up the phospholipid bilayer
hydrophobic tails
prevents the entry of hydrophilic and polar substances
makes up hte phospohlipid bilayer
What is the function of cholesterol in cell membranes
when the temperature increases above normal, the cholesterol holds the phospholipids bilayer together which ensures that the cell membrane remains intact and does not break apart. when the temperature decreases below normal, the cholesterol ensures that the phospholipids do not pack together too lightly so that there is an exchange of substances across the cell.
excyotosis
the bulk transport of molecules out of a cell
endocytosis
bulk transport into the cell
