Biology π | Movement in and out of cells | 3 Flashcards
What is diffusion?
The net movement of particles from a region of their higher concentration to region of their lower concentration.
Where do particles tend to spread to?
They spread from areas of high concentration to areas of low concentration, eventually evening out.
Why do particles spread from high concentration to low concentration areas?
Particles move around randomly, and when nearer to each other they collide and push each other to areas with a low concentration.
What is Brownian motion?
Brownian motion is when particles move around randomly at all times with kinetic energy.
How do particles move from extracellular fluids to a cytoplasm, in cells?
There are many particles in the extracellular fluids, that move through the cell membrane into the cytoplasm.
How does a cell membrane stop some particles from passing through?
The cell lipid membrane is negatively charged and so only small particles with no charge go through - particles that also have a negative charge being repelled.
How does diffusion support unicellular organisms?
Unicellular organisms only have one cell membrane between the air and the cell, and are small, so can support themselves simply by diffusing oxygen in.
Can diffusion provide animals like us with oxygen?
No, our skin is too thick and our body is too large.
Since humans do not have diffusion, what do we use to get oxygen?
We have created transport systems such as the circulatory system to provide us with oxygen.
How does diffusion work in earthworms?
Earthworms diffuse oxygen into their body and carbon dioxide out, through skin.
How does diffusion work in our lungs?
In the gas exchange, in air sacs, oxygen goes into the air sac and carbon dioxide goes into the blood stream.
How does diffusion work in leaves?
Oxygen and carbon dioxide diffuse through pores in epidermis, and then through spaces between cells.
What are the four factors affecting diffusion rate?
Temperature, concentration gradient, surface area, and distance.
Though having a high body temperature causes diffusion to speed up, why does too high of a temperature cause problems?
It causes the structure of proteins to break up, and things such as antibodies stop working.
How are alveoli adapted for diffusion?
Walls of alveoli and capillaries are only one cell thick. This means the particles have a short diffusion distance.
What do alveoli diffuse?
Oxygen, out of the alveoli. Carbon dioxide from blood to alveoli.
Where are alveoli found?
Mammals and organisms that breathe with lungs.
How are villi adapted for diffusion?
They have large surface area with many capillaries to increase diffusion rate.
What do villi diffuse?
Fatty acids, glycerol, proteins, amino acids into blood streams
Where are villi found?
In any animal at the beginning of the small intestine
How are nerve cells adapted to diffusion?
Synapse between cells let transmitters diffuse across and are short.
What do nerve cells diffuse?
Neurotransmitters.
Where are nerve cells found?
In nerves, in organisms with a nervous system.
How is the placenta adapted for diffusion?
Large surface area between the placenta and uterus wall, capillaries of mother closer to blood stream of baby.
What does the placenta diffuse?
Nutrients, water, oxygen, antibodies
Where is the placenta found?
In mammals with some exceptions.
What are the adaptations of spongy mesophyll walls for diffusion?
Lots of spaces are between to increase surface area; the leaf is very thin.
What is diffused in spongy mesophyll cells?
Oxygen, co2, and water vapour
Where are spongy mesophyll cells found?
Plant leaves.
What is the diffusion rate?
The distance travelled by movement of particles in a liquid or gas from an area of high concentration to an area of low concentration in a certain amount of time.
What is the concentration gradient?
The difference in concentration between 2 places.
Why does a higher temperature result in faster diffusion rate?
High temperature, more kinetic energy, more collisions, more pushing, faster diffusion.
How do we plan an experiment?
- Make the hypothesis
- Think of the dependent variables
- Independent variables
- Constant variables
- Mentioning apparatus and writing steps.
What is osmosis?
The net movement of water molecules from an region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution), through a partially permeable membrane.
What substances are needed in osmosis?
WATER ONLLYYY
Is energy required in osmosis?
No.
What is a place with higher solute concentration called?
Hypertonic
What is a place with lower solute concentration called?
Hypotonic
Why does water move from areas with low water potential to high?
Water molecules can fit through a semi permeable membrane, but solutes cannot.
What is visking tubing?
An artificial semi permeable membrane by humans.
What happens if too much water enters an animal cell?
It bursts as the cell membrane cannot hold it.
Why donβt plant cells burst in pure water?
The cell wall keeps it from bursting.
What happens if an animal cell is in a hypotonic solution?
Net movement of water is into the cell, as outside is more diluted. The cell cannot hold it and becomes rutured and may burst.
What happens if a plant cell is in a hypotonic solution?
Net movement of water is into the cell as the outside is more diluted. It becomes turgid (This is the normal state)
What is it called when the concentration of water is the same inside the membrane and outside?
Isotonic.
What happens to an animal cell in an isotonic solution?
The net movement of water is 0 and the cell is in its normal state.
What happens to a plant cell if in an isotonic solution?
Net movement of water is 0 and it becomes flaccid; plant wilts.
What happens to an animal cell if in a hypertonic solution?
The net movement of water is out of the cell, as the outside is more concentrated that the inside. It becomes shrinked and shrivels up.
What happens to a plant cell in a hypertonic solution?
The net movement of water is out of the cell, as the outside is more concentrated than in. It becomes plasmolysed, and shrinks. killing the cell as the cell membrane tears away from the wall.
What is the process a plant cell undergoes in a hypertonic solution for too long?
Plasmolysis.
What is turgor pressure?
The pressure to keep stems upright and to keep leaves flat so they can better absorb sunlight. Only when the plant cell has lots of water.
Define flaccid.
A cell that lacks turgidity. not plump but loose.
What is active transport?
The movement of particles through a cell membrane from region of low concentration to a region of high concentration, against concentration gradient, using energy from respiration.
Does active transport require energy?
Yes.
Does active transport require energy?
Yes.
What are examples of active transport?
Mineral ions in to plant roots, glucose from gut cells into intestinal cells, into blood.
What allows for active transport?
Carrier proteins.
How do carrier proteins force substances to move against their concentration gradient?
The molecule enters the transport protein, which changes shape and pushes it into the cell (better visualised)
What ions do root hair cells take in with active transport?
Nitrate ions.
How does the intestine use active transport?
Glucose can be actively transported from the lumen of the small intestine into cells of the villi.
How do kidney tubules use active transport?
Glucose is actively transported out of the tubule and into the blood.
How do root hair cells do active transport?
Carrier proteins push nitrate ions through the cell membrane and into the cytoplasm.
Active transport uses energy from _
Respiration.
