B2.2 exchange surfaces

Question 1

explain the need for exchange surfaces and a transform system in terms of surface area to ratio

Answer 1

• Organisms** must take in food, **oxygen and water, and other essential substances, from the environment
• . Plants also need carbon dioxide** for **photosynthesis. Organisms also need to remove waste substances.
• The rate of diffusion in osmosis and active transport is higher in cells with a larger surface area to volume ratio

Question 2

Describe how to calculate surface area to volume ratio

Question 3

What are the problems a multicellular organism may face when increasing in size

Answer 3

As the volume increases, surface area does not increase at the same rate.

• problem:Their surface area does not increase as fast as the volume .
• solution; Body systems that add additional absorbing area to exchange surfaces
• Problem:Their volume increasesDiffusion is not quick enough to move substances to where they’re needed in the organism’s body
• Solution: A transport system

Question 4

Describe some of the substances transported into and out of a range of organisms in terms of the requirements of those organisms

Question 5

what are the three main factors that effect the movement of substances

Answer 5

1. surface area to volume ratio
2. temperature
3. concertation gradient

Question 6

describe how surface area to volume ratio affects the movment of substances

Answer 6

• the rate of diffusion active transport and osmosis is higher in cells that have a larger surface area to volume ratio

Question 7

describe how temperature affects the movement of substances

Answer 7

• as particles in a substance get warmer
• they gain more energy and move faster
• as temperature increases substances move in and out of cells faster

Question 8

describe how the concentration gradient affects he movement of substances

Answer 8

• if there’s a big difference in concentration between the inside or outside of the cell
• substances move faster

Question 9

list the common features of exchange surfaces

Answer 9

• thin - for a short diffusion distance
• large area - achieved by being long and thin, flat, or folded
• moist - so that substances can be dissolved for diffusion to happen

Question 10

describe the structure of the circulatory system

• a pump (the heart)
• valves to ensure a one-way flow of blood

Answer 10

The circulatory system consists of:

• a system of tubes (arteries, capillaries and veins)
• a pump (the heart)
• valves to ensure a one-way flow of blood

Question 11

Describe the arrangements of vessels in the circulatory system

Answer 11

LungPulmonary arteryPulmonary veinLiverHepatic arteryHepatic veinKidneyRenal arteryRenal vein

Question 12

Describe the function of arteries in the circulatory system

Answer 12

Arteries carry blood away from the heart towards an organ

arteries away

Question 13

Describe the function of veins in the circulatory system

Answer 13

while veins carry blood from an organ towardsthe heart.

Question 14

Describe the function of veins in the circulatory system

Answer 14

while veins carry blood from an organ towardsthe heart.

Question 15

recal that the body has a double circulatory system

Answer 15

• two separate circuits
• blood passes through the heart twice

Question 16

Describe what the pulmonary circuit is for

h&l

Answer 16

• the pulmonary circuit is between the heart and lungs

Question 17

Describe what the systemic circuit is for

Answer 17

• the systemic circuit is between the heart and the other organs

Question 17

Describe what the systemic circuit is for

Answer 17

• the systemic circuit is between the heart and the other organs

Question 18

Describe the human circulatory system and the relat between gaseous exchange

Answer 18

• carbon dioxide diffuses** from blood into the air in the **alveoli
• oxygen diffuses from air in the alveoli into the blood, and is absorbed by haemoglobin in the red blood cells
• the pulmonary arterycarries deoxygenated blood and the pulmonary veincarries oxygenated blood To the lungs
  *

Question 19

Explain how the structure of the heart is adapted to its function

Question 20

Explain how the structure of arteries are adapted to its function

Answer 20

• Carry blood away from the heart (always oxygenated apart from the pulmonary artery
• Have thick muscular walls.
• because- they contain blood under high pressure.
• Have small passageways for blood

Answer 21

• Carry blood to the heart (always deoxygenated apart from the pulmonary vein which goes from the lungs to the heart).
• Have thin walls.
• Have larger passageways for blood (internal lumen).
• Contain blood under low pressure.
• Have valves to prevent blood flowing backwards.

Question 22

Explain how the structure of veins are adapted to its function

Answer 22

• Carry blood to the heart (always deoxygenated apart from the pulmonary vein which goes from the lungs to the heart).
• Have thin walls.
• becausse they Contain blood under low pressure.
• Have larger passageways for blood (internal lumen).
• Have valves to prevent blood flowing backwards.

Question 23

Explain how the structure of capilleriss are adapted to its function

Answer 23

• Found in the muscles and lungs.
• Microscopic – one cell thick.
• Very low blood pressure.
• Where gas exchange takes place - oxygen passes through the capillary wall and into the tissues, while carbon dioxide passes from the tissues into the blood

Question 24

Explain how red blood cells are adapted to their function

Answer 24

* they contain **_haemoglobin_** - a red protein that combines with oxygen * they have no **_nucleus_** so they can contain more haemoglobin and increase surface area * they have a **biconcave** shape (flattened disc shape) to maximise their surface area for oxygen absorption

Question 25

Explain how plasma is adapted to its function

Answer 25

primarily made from water **_urea_**, carbon dioxide and glucose, are soluble in water alows wide range of sunstances to be carried in blood

Question 26

Explain how water and mineral ions are taken up by plants

Answer 26

* Water: water is taken up from the roots to the rest of the plant using osmosis * mineral ions: active transport, against the concentration gradient

Question 27

Explain how the plant root cells are adapted to their function

Answer 27

a large surface area to increase the rate of absorption. They also contain lots of **_mitochondria**_, which release energy from _**glucose**_ during _**respiration_** in order to provide the energy needed for active transport.

Question 28

Describe the process of transpiration

Question 29

Describe the process of translocation

Question 30

Explain how the structure of the xylem is adapted to its function in the plant

Question 31

Explain how the structure of the phloem is adapted to its function in the plant

Question 32

Explain the effect of a variety of environmental factors on the rate of water uptake by a plant

Answer 32

* temperature * humidity * wind speed * light intensity

Question 33

Temperature effect on the rebate of transpiration

Answer 33

TemperatureIncreasedEvaporation and diffusion are faster at higher temperatures

Question 34

humidity

Answer 34

HumidityDecreased Diffusion of water vapour out of the leaf slows down if the leaf is already surrounded by moist air

Question 35

Wind speed

Answer 35

Moving air removes water vapour, increasing the rate of diffusion of water vapour from the leaf increashes the rate of tramspira

Question 36

effect of Light intensity on transpiration

Answer 36

transpiration rate: increased The stomata open wider to allow more carbon dioxide into the leaf for photosynthesis