movement of substances through cells Flashcards
What does a high concentration gradient mean
The difference between the concentrations of both areas is very large
What is diffusion?
The net movement of particles from an area of high concentration to an area of low concentration due to their kinetic energy across a concentration gradient
What are four factors that can affect diffusion
Temperature
Distance
Concentration gradient
Surface area to volume ratio
Describe how temperature affects the rate of diffusion
The higher the temperature the more kinetic energy
So more collisions
So faster the rate of diffusion
Will diffusion be quicker with a high concentration gradient or a low concentration gradient?
High concentration gradient
Will rate of diffusion be faster in high surface area to volume ratio or low surface area to volume ratio
And explain why
High surface area to volume ratio (eg 6:1)
Because there will be more space for diffusion to occur across less space relative to its size
Explain why humans are made of many cells rather than one
Entire Human body has low surface area to volume ratio
so diffusion would happen slowly
and oxygen would not be able to be supplied to the body fast enough
So single cells provide high surface area to volume ratios so diffusion happens quickly
What restricts the free movement of particles to move outside a cell
The partially permeable cell membrane
Explain three ways in which diffusion helps living organisms
- helps obtain nutrients (——
- helps in gas exchange for respiration—–) (——
- helps get rid of waste products——)
Which molecule for respiration moves through a leaf and where does enter from and where are they transported to?
Oxygen enters through the stomata and is transported to the mitochondria
Does diffusion require energy
No
Name two molecules that can not pass through the semi permeable membrane
and two that can
Starch and proteins CANT
glucose and amino acids CAN
Give an example of a cell adapted to diffusion and how it is adapted
The villi of the small intestine
It is folded so has an increased surface area to volume ratio
What is Osmosis
The diffusion of particles from a dilute solution to a concentrated solution across a semi permeable membrane
What is the water potential of a dilute solution
High water potential
What is the name given to two solutions with the same osmotic pressure
Isotonic solution
If a plant cell is placed in dilute solution, describe the movement of water and the name given to what happens to the cell
Water will move into the cell
Because water moves from dilute solutions(High water potential to concentrated solutions (low water potential )
cell becomes TURGID
If an animal cell is placed in dilute water, explain the movement of water and the name given to what happens to it
Water moves into the cell
Because water moves from dilute solutions(High water potential to concentrated solutions (low water potential )
This process is called LYSIS
If an animal cell is placed in concentrated solution of water, explain the movement of water and the name given to what happens to it
Water will move out
Because water moves from a more dilute solution(High water potential)to a more concentrated solution (low water potential)
Cell becomes CRENATED
If a plant cell is placed in concentrated solution of water, explain the movement of water and the name given to what happens to it
Water will move out of the cell
Because water moves from a more dilute solution(High water potential)to a more concentrated solution (low water potential)
The cell becomes FLACID
What is the name given to a plant cell that has lost toon,ugh water through osmosis
It become PLASMOLYSED
What is the name given to an animal cell placed in a dilute solution
Lysis
Why are red onions good to use for osmosis
They are pigmented so you can easily see the direction of water movement
Why does diffusion happen in terms of particles
Because of the kinetic energy of the particles
Which potato cylinder will have the greatest mass?
One placed in salty solution?
Or dilute solution?
Dilute solution
Is the concentration of carbon dioxide higher in the human cell or outside the human cell
Inside
When the smallest of the agar cubes is placed in hydrochloride acid, what happens to it
Water travels inside the agar because diffusion happens from an area of high concentration to an area of low concentration
It becomes colorless the fastest
What happens to the cytoplasm and membrane when a plant cell is placed in an extremely concentrated solution
They split apart and gaps appear
The cell is plasmolysed
Why is there less water movement in animal cells
Because they have no cell wall so cannot resist changes in pressure
What happens to the vacuole when water moves into a plant
It pushes against the cell membrane
Which organelle is high turgor pressure caused by
The cytoplasm pushing against the cell membrane
What state is a plant in when it is in Turgor
It is turgid
Can diffusion happen in solids
No
Because diffusion requires the movement of particles
Does diffusion need a membrane
No, can occur in the air for example
Does osmosis require a membrane
Yes
What is the definition active transport
The movement of particles form an area of low concentration to an area of high concentration agaisnt a concentration gradient by using the energy from respiration in the form ATP
Does active transport transport require energy, and why
Yes
Because particles are moving against a concentration gradient
Give an example of where active transport takes place in the body and why
From the lumen of the small intestine to the blood stream
as the cells in the blood stream are more concentrated
Which organelle does the energy come from for active transport
The mitochondria
Give an example of active transport in a plant and why it happens
When minerals are transported from the soil to the root hair cell because the content of the soil are much less concentrated than the cytoplasm of the root hair cell
Why is active transport of glucose important in the kidney
So that glucose can be reabsorbed into the blood and not lost in urine
Why should you convert original change in mass to percentage change in mass in an experiment to show effect of surface area on osmosis
Because you have different masses so percentage mass will give a more valid comparison
Explain the effect of the different SA:Vol ratios on the mass of a potato in dilute solution
(2)
The larger the surface ares to volume ratio, the greater the percentage increase of mass
So The faster the rate of osmosis
Cube of side- 0.5
What is the surface area of the cube
0.5 x 05
=0.25
0.25x6=
1.5
Two leaves are covered in petroleum jelly
(LeafA)One is covered from only the upper half
(LeafB )The other one is covered only from the lower half
Which one decreases the most mass and why?
Leaf A as more water is lost as more surface area is exposed
Beth draws the outiline of a leaf to investiagte the surface area.
It covers approximately 60 squares on squared paper
What is the total surface area of the leaf?
60 x 2= 120
Because total means both sides of the leaf
Explain how nitrate ions get into the root hair cells of a plant
Through the process of active tranpsort,
when ions move from area of low concentration(in soil) to an area of high concentration(in the root hair cell)
against a concentration gradient,
using energy in the form ATP from respiration
A doctor uses a dialysis machine to remove urea from the blood. But the machine also maintains normal blood glucose concentration.
Suggest now the concencentration of glucose in the solution around the tubing of the machine can help maintian normal glucose level in the blood.
Keep the concentration of glucose in the machine the same as the concentration in the machine.
So no net movement out of blood
What is meant by thr independant variable
Thr variable thst you are changing
If i increase the temperature of a solution containing seedlings that uses active transport to transport water into its cells, what will happen to the uptake of solution in the seedling
The rate of uptake will increase,
because higher temperatures makes the ions in the soltuion move faster
A pot of seedlings contains a soltuion around them which uses active transport to transport water into the cell of the seedlings.
If i increase the concentration of the solution , what happens to the uptake of solution into the cell
Nothing
Because increasing concentration gradient does not have an effect on active transport
How do root hair cells obtain water from the soil
Through the process of osmosis in the root hair cells
, because water travels from a more dilute solution to a less dilute solution across a semi permeable membrane
Adding too much water into air spaces of soil prevents mineral ions from being absorbed.
Explain why
There is no oxygen
So cells cannot respire and thus release ATP
so active transport can not take place without ATP
