Dissolved Substances

Question 1

How does water often move across boundaries?

Answer 1

Osmosis

Question 2

What is osmosis?

Answer 2

It is the diffusion of water from a dilute (high water concentration) to a more concentrated solution (low water concentration) through a partially permeable membrane that allows the passage of water molecules

Question 3

Differences in the concentrations of the solutions inside and outside a cell causes water to move:

Answer 3

Into and out of the cell by osmosis

Question 4

What do most soft drinks contain?

Answer 4

Water
Sugar
Ions

Question 5

What happens of water and ions are not replaces?

Answer 5

The ion/water balance of the body is disturbed and the cells do not work as efficiently

Question 6

What is active transport?

Answer 6

Substances are sometimes absorbed against a concentration gradient, this requires the of energy from respiration. Active transport enables cells to absorb ions from very dilute solutions (high water levels)

Question 7

Many organ systems are specialised for exchanging materials. The effectiveness of an exchange surface is increased by:

Answer 7

Having a large surface area
Being time, to provide a short diffusion path
(In animals) having an efficient blood supply
(In animals, for gaseous exchange) being ventilated

Question 8

What gas and solute exchange surfaces in humans and other organisms adapted to do?

Answer 8

To maximise effictivness

Question 9

In an organism, what increases the difficulty of exchanging materiLs?

Answer 9

The size and complexity

Question 10

Where and what increases the surface area in human bodies?

Answer 10

The surface area of the lungs is increased by the alveoli

The surface area of the small intestine is increased by villi

Question 11

What does villi provide?

Answer 11

A large surface area with an extensive network of capillaries to absorb the products of digestion by diffusion and active transport

Question 12

Water in drinks help to…

Answer 12

Rehydrate body cells

Question 13

What type of membrane is the cell membrane?

Answer 13

Partially permeable

Question 14

Why does active transport require energy?

Answer 14

The particles are being absorbed against a concentration gradient

Question 15

Why is glucose used during exercise?

Answer 15

Glucose is used in the process of respiration to release energy

Question 16

How are mineral ions lost in the body during exercise?

Answer 16

By sweating

Question 17

How do dissolved substances more?

Answer 17

By diffusion and by active transport

Question 18

What do sports drinks contain?

Answer 18

•Sports drinks contain mostly water, with glucose and salts to rehydrate you efficiently
•However, there is evidence that they are no better than many other drinks
•For short periods of exercise (less that 1 hour), water would be enough
Orange squash would also replace lost glucose
•Many milk drinks could actually contain more necessary components than many expensive sports drinks

Question 19

Evaluate the claims of sports drinks

Answer 19

Sports drinks manufacturers often make claims about the performance benefits of using their branded sports drinks, but it is important that these claims are evaluated based on valid data from controlled trials of a large sample of athletes.

Different manufacturers put slightly different amounts of sugar and mineral ions in their sports drinks, and therefore each brand will potentially have differing effects on an athlete’s performance.

Question 20

What do the different parts in sports drinks help the body do?

Answer 20

Sugar - keeps glucose levels high
Water, sugar and ions - passing into the bloodstream and then cells
Water - helps absorb nutrients
Sugar - helps athletes do continue exercising for longer
Water - helps moisten the lungs for breathing
Ions - keep cells working properly especially those in the nervous system
Water - helps regulate the body temperature