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AQA Biology AS > Exhange and Transport Systems > Flashcards

Exhange and Transport Systems Flashcards

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1
Q

Fick’s Law states what 3 things are essential to an efficient transport system [3]

A
  • Surface Area
  • Concentration Gradient
  • Pathway of Exchange
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2
Q

Organisms that live in hot areas have a ___________ to allow for more easy heat loss? [1]

A

Large Surface Area : Volume

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3
Q

Give some common adaptions or an animal living in adversely hot conditions [3]

A
  • No hair
  • Blood vessels close to skin
  • Large ears
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4
Q

Plants that live in extreme environments are called what? [1]

A

Xerophytes

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5
Q

Animals that live in extreme environments are called what? [1]

A

Extremophiles

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6
Q

How do unicellular organisms exchange gases? [1]

A

Via simple diffusion through the cell membrane

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7
Q

Why do fish use a countercurrent system for gas exchange? [2]

A

Because it means that blood always meets water which has a greater % saturation of O2 so a concentration gradient is always maintained

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8
Q

What is the countercurrent system used in fish? [1]

A

Means that water and blood flow in opposite directions

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9
Q

What are the gill filaments in fish called? [1]

A

Lamella

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10
Q

Explain how lamella increase the rate of exchange? [1]

A

They increase the surface area of the gills

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11
Q

What are the openings in an insects skeleton called? [1]

A

Spiracles

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12
Q

Explain how insects exchange gases with their environment? [5]

A
  • Oxygen enters the spiracels
  • Oxygen travels down a concentration gradient to the cells
  • Down the trachea into the tracheaoles
  • Tracheaoles have thin walls so O2 can diffuse through them directly to the respiring cells
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13
Q

If more gases required how may an insect speed up this process of gas exchange [1]

A

Through pumping its abdomen

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14
Q

Name from top to bottom the structure of a leaf? [4]

A
  • Waxy cuticle
  • Upper epidermis
  • Palisade layer
  • Mesophyll layer and air spaces
  • Lower Epidermis / Guard Cells / Stomata
  • Waxy Cuticle
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15
Q

Give some ways in which plants are adapted to reduce water loss? [3]

A
  • Stomata sunken in pits
  • Less stomata
  • Thicker waxy cuticle
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16
Q

Describe how O2 reaches the alveoli [3]

A
  • Moves in down pressure gradient
  • Down Trachea, Bronchi, Bronchioles
  • Diffuses into blood down gdt
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17
Q

Describe the process of inspiration [5]

A
  • External intercostals and diaphragm contract
  • Ribcage moves up and out and diaphragm flattens
  • Volume of Thoracic cavity increases so the pressure decreases
  • Air moves in down a pressure gradient
  • This process requires energy
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18
Q

Describe the process of expiration [5]

A
  • External intercostals and diaphragm relax
  • Ribcage moves up and out and diaphragm curves
  • Volume of Thoracic cavity decreases so the pressure increases
  • Air moves out down a pressure gradient
  • This process does not require energy
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19
Q

How does forced expiration differ from normal expirations? [3]

A
  • Internal intercostals contract pulling the ribcage further down and in
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20
Q

State two ways that the alveoli are adapted for efficient gas exchange? [2]

A
  • There are thousands so MASSIVE surface area
  • Alveolar epithelium is very thin so SHORT diffusion pathway
  • Constant blood flow MAINTAINS a concentration gradient
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21
Q

Describe what Pulmonary Tuberculosis (TB) is and how does it affect gas exchange? [4]

A
  • Hard lumps form around bacteria in the lungs
  • Infected tissue dies so gas exchange surface is reduced
  • This reduces the tidal volume
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22
Q

Describe what Fibrosis is and how does it affect gas exchange? [4]

A
  • Formation of scar tissue in lungs as a result of an infection or inhalation of foreign particles
  • This scar tissue is thicker and less elastic than the normal tissue found in the lungs
  • So lung cant expand as much and so cant hold as much air
  • Diffusion is also slower across the thicker scar tissue
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23
Q

Describe what Asthma is and how does it affect gas exchange? [4]

A
  • Airways become inflamed and irritated
  • Smooth muscle in bronchioles contracts reducing the lumen size
  • More mucus is also produced
  • Less air can get to the lungs
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24
Q

Describe what Emphysema is and how does it affect gas exchange? [4]

A
  • Caused by smoking or long term air pollution
  • Foreign particles cause inflammation and so phagocytes are attracted to the area
  • Phagocytes produce an enzyme which breaks down the elastic tissue in the lungs
  • Alveoli cant contract to expel air
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25
Q

Name two ethical issues with the dissection of an animals organs? [2]

A
  • Morally wrong just to kill an animal so a dissection can be carried out
  • Concerns that animals bread for research may not be bread in a human way
26
Q

Name the substrates and products of the following enzymes? [3]

  • Maltase
  • Sucrase
  • Lactase
A
  • Maltose -> Two glucose
  • Sucrose -> Glucose + Fructose
  • Lactose -> Galactose + Glucose
27
Q

Lipids are broken down by X into Y and Z [3]

A

X lipase
Y fatty acids
Z glycerol

28
Q

How are monosaccharides absorbed in the ileum [1]

A

Transported across ileum epithelial cells by specifc transporter proteins

29
Q

Why do bile salts help speed up digestion? [2]

A

Emulsify small lipid droplets

30
Q

Describe the action of Endopetidases and how these differ from Exopeptidases [3]

A

Endo. hydrolyse bonds within a protein, Exo. hydrolyse peptide bonds at the end of a protein molecules

31
Q

Explain how monoglycerides and fatty acids are absorbed in the Ileum? [2]

A
  • Micelles help move them to the epithelium

- Break don and constantly reform

32
Q

Explain how amino acids are absorbed in the Ileum? [2]

A
  • Via co transport (just like glucose)
33
Q

Describe the structure of Haemoglobin [2]

A
  • Four polypeptide chains

- Prosthetic Fe group ( Haem group )

34
Q

How many ATOMs can Hb associate with? [2]

A
  • 8 ATOMS
35
Q

What is meant by P(O2) [1]

A

The partial pressure of oxygen

36
Q

What is meant by Hb’s affinity for O2 [2]

A

The higher the affinity for O2 the more readily it will load O2

37
Q

Describe and Explain the typical Hb dissociation curve for a human. [4]

A
  • When P(O2) is high eg in the lungs. Hb. has a high affinity for oxygen so it will load lots of oxygen
  • When P(O2) is low eg at the respiring tissues Hb. has a low affinity for oxygen which means that it unloads the oxygen to be used in respiration
38
Q

Describe the Bohr shift [5]

A
  • When cells respire they produce CO2 this acidifies in the blood forming carbonic acid
  • So rate of unloading is increased, can be said that Hb. has a lower affinity for O2 at higher P(O2)
  • Overall more oxygen is released
39
Q

Name the blood vessel taking blood away from the heart [1]

A

Aorta

40
Q

Name the blood vessel taking blood away from the kidneys [1]

A

Renal Vein

41
Q

Name the blood vessel taking blood back to the heart from the lungs [1]

A

Pulmonary Vein

42
Q

Name the blood vessel taking blood from the gut to the liver [1]

A

Hepatic Portal Vein

43
Q

Name the blood vessel taking blood to the kidneys [1]

A

Renal Artery

44
Q

In general arteries take blood ______ [1]

A

Away from the heart

45
Q

Describe how tissue fluid is formed [5]

A
  • At arteriole end hydrostatic pressure in the capillary is greater than in the extracellular space so fluid is forced out
  • At venule end there are less water molecules present and large soluble proteins in the blood lower the water potential so water is drawn back in by osmosis down the water potential gradient
  • Any excess tissues is drained back into the circulatory system via the lymphatic system
46
Q

Why is the left side of the heart thicker [2]

A

Because it need to pump more powerfully to pump blood all the way around the body

47
Q

Describe the 3 main events of the Cardiac cycle [6]

A
  • Atrial Systole -> Ventricles are relaxed and atria contract decreasing the volume of the chambers hence increasing the pressure so blood pushed through AV valves into the ventricles
  • Ventricular Systole -> Ventricles contract so volume decreases and pressure increases, pressure higher in ventricles so AV vales shut, semi lunar valves open so blood pushed into artery
  • Atrioventricular Diastole -> SL valves shut both parts of the heart are now relaxed
48
Q

What does systole mean [1]

A

Contraction

49
Q

What does diastole mean [1]

A

Relaxed

50
Q

Describe the electrical activities of the heart [4]

A
  • Wave of electrical activity initiated by the SAN node in atria causing the atria to contract
  • Wave reaches non conducting tissue at the division between atria and ventricles but activates AV node
  • Atria contract from the top down squeezing all of the blood into the ventricles
  • Electrical energy moves down bundle of his where signal is delayed before it spreads out along pukiji fibers
  • Ventricles then contract from the apex up
51
Q

Describe how an atheroma is formed? [4]

A
  • Damage to the endothelium
  • WBC’s and fats (lipids) form fatty streaks under endothelium
  • Plaque builds up which reduces lumen size therefore reducing blood flow
52
Q

What is an aneurism? [1]

A

Balloon like swelling

53
Q

What is a thrombus [1]

A

An atheroma that is mobile and could block other smaller arteries

54
Q

What is myocardial infarction? [2]

A

When the cardiac muscle does not get enough oxygen for respiration due to a blockage in the coronary artery so can not contract properly

55
Q

Give 3 things that can increase the risk of CHD [3]

A
  • Diet that is high in saturated fat and so is high in bad cholesterol
  • Smoking
  • High blood pressure
56
Q

What plant tissues transport sugar and dissolved substances? [1]

A

Phloem

57
Q

What plant tissue transports water? [1]

A

Xylem

58
Q

What four factors affect the rate of transpiration [4]

A
  • Light
  • Temperature
  • Humidity
  • Wind
59
Q

MAKE SURE YOU KNOW HOW TO USE A POTOMETER

A

cba to write out a method

60
Q

Describe the mass flow hypothesis of Phloem transport [6]

A
  • Active transport used to load solute from the companion cells into the sieve tube element at the source this lowers the water potential at the source so water moves in by osmosis, this then creates a high pressure at the source
  • At the sink end solutes are removed to be used, this increases the water potential so water also leaves by osmosis, this creates an area of lower pressure
  • This results in a pressure gradient from source end to the sink so this gradient pushes the solutes along
61
Q

Describe the Cohesion - Tension theory [5]

A
  • Water evaporates from the leaves at the ‘top’ of the Xylem
  • This creates tension which pulls more water into the leaf
  • Water molecules are cohesive because of their polarity so when some molecules are pulled the rest follow like a column of water so overall flow upwards
  • Water enters the stem through the roots
62
Q

How does water enter the root hair cells? [2]

A

Ions are actively transported in which lower the water potential inside so water moves down the water potential gradient into the roots by osmosis

AQA Biology AS (8 decks)

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