B3.1 Exchange of Materials Flashcards Preview

GCSE Biology B3 - VS > B3.1 Exchange of Materials > Flashcards

Flashcards in B3.1 Exchange of Materials Deck (27)
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1
Q

Dissolved Substances move by which two processes? (2)

A

Diffusion and Active Transport

2
Q

Water often moves across boundaries by which process?

A

Osmosis

3
Q

Define Osmosis

A

Osmosis is the diffusion of water from a low concentration to a high concentration through a partially permeable membrane.

4
Q

Define Active transport

A

Active transport is the process by which dissolved molecules move across a cell membrane from a low concentration to a high concentration, against the concentration gradient. This requires the use of energy provided from respiration.

5
Q

The effectiveness of an exchange surface is increased by what 4 factors?

A
  • Having a large surface area
  • Being thin, to provide a short diffusion path.
  • (in animals) having an efficient blood supply.
  • (in animals, for gaseous exchange) being ventilated.
6
Q

In humans the surface area of the lungs is increased by which structure in the lungs?

A

The alveoli

7
Q

In humans the surface area of the small intestine is increased by which structure?

A

Villi

8
Q

How does the villi provided a larger surface area?

A

By having an extensive network of capillaries to absorb the products of digestion by diffusion and active transport.

9
Q

Where are the lungs located in the body, and are protected by what?

A
  • Upper part of the body (thorax)

- Protected by the ribcage and separated from the lower part of the body (abdomen) by the diaphragm.

10
Q

When we breathe, which gas diffuses in, and which gas diffuses out?

A
  • Oxygen diffuses into the bloodstream

- Carbon Dioxide diffuses out of the bloodstream into the air.

11
Q

What happens when we breathe in? (4)

A
  • Intercostal muscles between the ribs and the diaphragm contract.
  • Ribcage moves out and up, and diaphragm becomes flatter.
  • Volume of the thorax increases.
  • Pressure of the thorax decreases as air is drawn in.
12
Q

What happens when we breathe out? (4)

A
  • The intercostal muscles of the ribcage and diaphragm relax.
  • The ribcage moves down and in and the diaphragm becomes domed.
  • The volume of the thorax decreases.
  • The pressure increases and air is forced out.
13
Q

The movement of air into and out of the lungs is know as what process?

A

Ventilation

14
Q

Give three reasons why a person may not be able to get enough oxygen into their bloodstream? (3)

A
  • If the alveoli are damaged, the surface area for gas exchange is reduced.
  • If the tubes leading to the lungs are narrowed, less air can be moved through them.
  • If the person is paralysed, their muscles will not work to pull the ribcage up and out.
15
Q

Describe the process of how an ‘iron lung’ works. (4)

A
  • Used for people with polio who are paralysed.
  • Covers the whole body of the patient apart from the head.
  • The pressure in the capsule (iron lung) is mechanically lowered to allow the lungs to expand and take in air and then raised to make the lungs contract and expel air.
  • However the blood flow in the lower part of the body can be poor and cause an increase in circulation side effects.
16
Q

How are modern ventilators better than the iron lung? (4)

A
  • Modern ventilators work by pumping air in a go/stop cycle, using a mouth piece connection, directly into the lungs to expand them and push out the ribcage.
  • When the pump temporarily stops, the ribcage relaxes, allowing the lungs to contract and get rid of the air.
  • This is a much more convenient method, and it doesn’t interfere with the body’s blood supply.
  • However there can be problems if the alveoli bursts, then the body can’t cope with the artificially increased air supply.
17
Q

What do most sport drinks contain, which is vital during exercise or other physical activities? (3)

A
  • Water to replace water lost when sweating.
  • Glucose (sugar) to replace the sugar used for energy released in exercise.
  • Mineral ions to replace those lost in sweating.
18
Q

What does the term “isotonic” mean, with regards to sport drinks?

A

If the drink concentration matches the body fluids the solution is called isotonic.

19
Q

Define transpiration?

A

The loss of water vapour from the leaves of plants through the stomata when they are opened to allow gas exchange for photosynthesis.

20
Q

In plants Carbon dioxide enters the leaves by which process?

A

Diffusion

21
Q

In plants most of the water and mineral ions are absorbed by which plant organ?

A

Roots.

22
Q

What increases the surface area of the roots?

A

Root Hairs

23
Q

What increases the surface area of leaves?

A

Increased by flattened shape and internal air spaces.

24
Q

What is the role of the stomata?

A

Stomata open and close, allowing CO2 in, and O2 out during the process of photosynthesis.

25
Q

Plants mainly lose water vapour from which side of the stomata.

A

Plants lose most of their water from the underside of their stomata.

26
Q

Evaporation is more rapid in what sort of conditions? (3)

A

Hot, dry, and windy conditions.

27
Q

The opening and closing of the stomata is controlled by which group of cells?

A

Guard Cells.