cell organisms Flashcards
1
Q
what is the definition of diffusion?
A
- a random movement of molecules from a higher concentration to a lower concentration.
2
Q
what does a partially permeable membrane mean?
A
- allows “some” molecules to come inside the cell.
3
Q
- what is the ‘Brownian Motion’?
A
- it moves randomly
- energy comes from a kinetic energy
4
Q
- Factors that influence diffusion:
A
- surface area to volume ratio:
. the bigger a cell, the smaller the surface area
. the smaller a cell, the bigger the surface area
5
Q
3 factors that affect the rate of diffusion:
A
- Distance
- Temperature
- Concentration gradient
6
Q
what does distance mean?
A
- the smaller the distance, the faster the molecules travel faster
- blood capillaries and the alveoli have one cell thick
7
Q
what does the temperature mean?
A
- the higher the temperature, the faster the molecules move.
8
Q
what does the concentration gradient mean?
A
- the higher the difference in concentration, the faster the movement across it occurs.
- the higher concentration, more random collusions.
9
Q
what is the definition of an ‘active transport’?
A
- the movement of particles through a cell membrane from a region of a lower concentration gradient to a higher concentration using energy from respiration.
10
Q
Does diffusion happen naturally?
A
yes, it is a passive.
11
Q
what is ‘ ions ‘?
A
- positive/ negative charge
12
Q
what are the three steps in active transport?
A
- BINDING
- changes shape of the molecule
- release of the substances
13
Q
what is the definition of ‘osmosis’?
A
- a net movement of a high concentration to a low concentration across a partially permeable membrane.
- high water potential to a low water potential
14
Q
what does turgid mean?
A
- more water molecules means it is turgid = means it is ‘rubber’.
turgid = will be hard/ more water.
15
Q
what does plasmolysis mean?
A
- it will be softer, not a lot of water is left so therefore a lower water potential.
