Chapter 3 - Movement In And Out Cells

Question 1

What is diffusion?

Answer 1

It is the net movement of particles from an area of high concentration to an area of low concentration down a concentration gradient as a result of the random movement of particles.

Question 2

Factors that affect rate of diffusion and how they affect diffusion.

Answer 2

Surface area - as the surface area increases, the rate of diffusion increases. More space available.

Temperature - as temp increases, rate of diffusion increases as molecules gain more kinetic energy

Concentration gradient - as concentration gradient increases so does rate of diffusion

Diffusion distance - as the distance shortens, the rate of diffusion increases due to having less distance to travel

Question 3

Define the term osmosis

Answer 3

It is the net movement of water molecules from an area of high water potential to an area of low water potential through a partially permeable membrane

Question 4

Define turgid

Answer 4

When a cell is swollen due to high water content

Question 5

Define turgor pressure

Answer 5

The pressure on the cell wall from the cell membrane pushing upon it due to cell becoming turgid as water moves in as a result via osmosis

Question 6

Define flaccid

Answer 6

The cells shrinks but cell membrane does not peel away from the cell wall. Happens when water moves out of the cell

Question 7

Define plasmolysis

Answer 7

Occurs when there is too little water in cells, in plant cells the cell membrane peels away from the cell wall

Question 8

What is the importance of water in cell?

Answer 8

It maintains the cells structure by maintaining turgor pressure and provides as a medium for in which metabolic reactions occur. Acts as a temperature buffer due to waters high heat capacity. Helps maintain temperature for enzymes

Question 9

Define the term active transport.

Answer 9

It is the movement of molecules against a concentration using energy from respiration. Molecules transported from area of low concentration to an area of high concentration

Question 10

Explain how active transport works in terms of carrier proteins

Answer 10

Carrier proteins are found in cell memebrane and allow passage through it. The particles from side of low concentration bind to it and energy from respiration causes it to change shape forcing the molecule through it to side with high concentration