bio - specialised cells and cell transport

Question 1

Why are cells specialised?

Answer 1

To carry out specific functions, cells become specialised as the organism develops

Question 2

How do cells in an organism develop?

Answer 2

They develop specific sub -cellular structures, so they can carry out their functions.

Question 3

What is the function of a sperm cell and how is it specialised?

Answer 3

Function - to fertilise the egg
Specialised - long tail for speed, lots of mitochondria for energy, stores digestive enzymes to break down the egg.

Question 4

What is the function of a nerve cell and how is it specialised?

Answer 4

Function - carry electrical impulses and provide rapid communication
Specialised - lots of dendrites to make communication to other nerve cells, axon for nerve impulses from one place to another

Question 5

What is the function of a muscle cell and how is it specialised?

Answer 5

Function - work together in tissues to move the bones of a skeleton
Specialised - mitochondia for energy needed for chemical reactions

Question 6

What is the function of a root hair cell and how is it specialised?

Answer 6

Function - take in water and minerals
Specialised - large surface area so more water can move into the cell, mitochondria as energy needed for active transport

Question 7

What is the function of a xylem cell and how is it specialised?

Answer 7

Function - allows continuous flow of water and minerals
Specialised - lignin in cell wall as provides strength

Question 8

What is the function of a phloem cell and how is it specialised?

Answer 8

Function - connects cells to transport food by photosynthesis
Specialise - sieve plates as allow water carrying dissolved food to move freely.

Question 9

What is diffusion?

Answer 9

the spreading out of particles in solution or particles of a gas, resulting in movement from an area of high concentration to an area of lower concentration.

Question 10

Example of diffusion

Answer 10

substances transported in and out of cells by diffusion are oxygen and CO2 in gas exchange and of the waste product (urea)

Question 11

What are factors that affect the rate of diffusion?

Answer 11

• difference in concentration
• the temp
• surface area of the membrane

Question 12

What is osmosis?

Answer 12

The diffusion of water from a dilute solution to a concentrated solution thro a partially permable membrane.

Question 13

What is an isotonic?

Answer 13

Means the amount of dissolved solutes the the same on the outside of the cell as the inside, so there is no difference in the concentration of water.

Question 14

Hypotonic?

Answer 14

Means there are more solutes inside the cell than outside, therefore inside the cells has a lower concentration of water.

Question 15

Hypertonic?

Answer 15

There are more solutes on the outside of the cell than the inside, so there is a lower concentration of water on the outside of the cell.

Question 16

change in mass as a %

Answer 16

change in mass/starting mass * 100

Question 17

What is active transport?

Answer 17

Moves substances from a more dilute solution to a more concentrated solution. THIS REQUIRES ENERGY

Question 18

Example of active transport?

Answer 18

Active transport allows mineral ions to be absorbed into plant root hairs from a very dilute solutions in the soil.

Question 19

Why is exchanging materials with the environment more difficult in multicellular organisms?

Answer 19

Due to their smaller surface area , so they need specialised organ systems for exchange.

Question 20

How exchange surface area adapted for exchanging materials.

Answer 20

• they’re thin - substances have a short distance to diffuse
• they have a large surface area - so lots of substabnces can diffuse at once
• they maintain a concentration grandient (good blood flow) so substances keep diffusing in the right direction
• they are often moist