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AQA A level Biology > Organisms exchange systems within their environment > Flashcards

Organisms exchange systems within their environment Flashcards

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1
Q

Smaller organisms SA:V ratio

A

Larger surface area to volume ratio

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2
Q

Larger organisms SA:V ratio

A

Smaller surface area to volume ratio

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3
Q

Fish gill structure

A

Made up of gill filaments attached to gill arch stacked up in a pile. Right angled to filaments are gill lamellae increasing SA.

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4
Q

Counter current flow

A

Blood flowing through lamellae in the gills, flows in one direction
water flows over fish in opposite direction
- water always has a higher concentration of oxygen than the blood (creates steep concentration gradient)

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5
Q

Adaptations of lamallae

A

Lots of blood capillaries increasing blood supply
Thin layer of cells creating a short diffusion pathway

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6
Q

Limiting water loss in insects

A
  • Small SA:V ratio
  • Waterproof coverings (exoskeleton/waxy cuticle)
  • Spiracles use muscles to close if dehydrated
  • Tiny hairs surround spiracles to retain water and decrease water potential, decreasing diffusion rate
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7
Q

Limiting water loss in plants

A
  • Waxy cuticle
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8
Q

What are xerophytes?

A

Plants which are adapted to living in areas where water is in deficit (cacti).

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9
Q

Adaptation of xerophytes

A

Thick cuticle, rolling up leaves, hairy leaves, stomata in pits or grooves, reduced SA:V ratio

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10
Q

Inspiration

A
  • External intercostal muscles contract causing ribs to move up and out
  • Diaphragm contract and so moves down and flattens increasing the volume of the thoracic cavity
  • Atmospheric pressure is greater than in lungs and so air is rushed in the lungs
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11
Q

Expiration

A
  • External intercostal muscles relax causing ribs to move down and in
  • Diaphragm relax and so moves up and becomes dome-shaped decreasing the volume of the thoracic cavity
  • Atmospheric pressure is smaller than in lungs and so air is rushed out the lungs
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12
Q

Digestive system function

A

Digests and processes food

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13
Q

Parts of digestive system

A

Oesophagus, stomach, ileum, large and small intestine, rectum, salivary glands, pancreas

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14
Q

Physical breakdown of digestion

A

The breaking down of food into smaller pieces by structures (makes it possibe to ingest, provides a large SA for chemical digestion)
- Teeth
- Muscles in the stomach wall

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15
Q

Chemical breakdown of digestion

A

Hydrolysis of large, insoluble molcules into smaller soluble ones.
- Enzymes

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16
Q

Carbohydrase (digestive enzyme)

A

Hydrolyses carbohydrates into monosaccharides.
Amylase (produced in mouth and pancreas)
- hydrolyses glycosidic bonds of starch into maltose in salivary glands and pancreas
Maltase (produced by lining of ileum)
- hydrolyses maltose from starch breakdown into a-glucose

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17
Q

Lipase (digestive enzyme)

A

Hydrolyse lipids into glycerols and fatty acids.
Lipase (produced in pancreas)
- hydrolyses ester bonds to fatty acids and monoglycerides in the small intestine

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18
Q

What is emulsification?

A

The process by which lipids are split into tiny droplets micelles by bile salts (produced in liver).
- increases SA of lipids to speed up action of lipase

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19
Q

Protease (digestive enzyme)

A

(produced in stomach) Hydrolyse proteins to amino acids.
Endopeptidase- hydrolyse peptide bonds within polypeptide chains to produce dipeptides
Exopeptidase- hydrolyse peptide bonds at the ends of polypeptide chains to produce dipeptides
Dipeptidase- hydrolyse dipeptides into amino acids which are released into the cytoplasm of the cell

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20
Q

Structure of the ileum

A
  • Functioned to absorb the products of digestion
    Wall is folded and possesses finger- like projections known as villi situated between lumen and the blood and tissues of body.
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21
Q

What are the adaptations of the villi?

A
  • Large quantity increasing SA
  • Very thin creating short diffusion pathway
  • Contain muscle to move maintaining diffusion gradients
  • Good blood supply maintaining diffusion gradient
  • Epithelial cells have microvilli further increasing SA
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22
Q

Absorption of amino acids and monosaccharides

A
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23
Q

Absorption of triglycerides

A
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24
Q

The role of haemoglobin

A

To load, transport and unload oxygen

25
Q

What is haemoglobin?

A

Haemoglobin is a protein with a quaternary structure.

26
Q

Structure of the human heart

A

Veins- vena cava (deoxygenated), pulmonary vein (oxygenated)
Arteries- aorta (oxygenated), pulmonary artery (deoxygenated)
Right atrium and left atrium
Right ventricle and left ventricle

27
Q

What is the function of valves?

A

To prevent the backflow of blood and maintain an unidirectional flow

28
Q

What are the two valves?

A

Atrioventricular valves
Semi- lunar valves

29
Q

How is the heart supplied with oxygen?

A

Coronary arteries which branch off aorta
Blockage of these can cause myocardial infarction (heart attack)

30
Q

Cardiac output

A

Volume of blood pumped by one ventricle of the heart in one minute
Cardiac output = heart rate x stroke volume

31
Q

Heart rate

A

The rate at which the heart beats

32
Q

Stroke volume

A

Volume of blood pumped out at each beat

33
Q

Arteries

A

Carry blood away from the heart and into arterioles

34
Q

Artery structure

A
  • Thick muscular wall
  • Narrow lumen
  • Thick elastic layer
  • No valves
  • High pressure
35
Q

Arterioles structure

A

-Thicker muscular wall than arteries to narrow lumen and restrict blood flow into capillaries
-Thinner elastic tissue than arteries and pressure is lower

36
Q

Vein structure

A
  • Thin muscular wall
  • Thin elastic layer
  • Valves
  • Low pressure
  • Wide lumen
37
Q

Capillary structure

A
  • One cell thick creating short diffusion pathway
  • Narrow lumen reducing diffusion pathway
  • Large quantity increasing SA
  • Highly branched providing SA
  • Spaces between lining of endothelial cells so white blood cells can escape to deal wuth infections
38
Q

Capillaries

A

Exchange metabolic materials such as O and CO2 between blood and cells of body

39
Q

Veins

A

Carry blood to heart

40
Q

Tissue fluid

A

Watery liquid containing glucose, amino acids, fatty acids, ions in solution and oxygen. Supplying tissues with these substances, receiving carbon dioxide and other waste products from tissues

41
Q

Formation of tissue fluid

A
42
Q

How does air move in the insects?

A

Moves in the insect via the spiracles in the outer surface, this occurs by rhythmic abdominal movements.
Air then moves into the tracheae to the tracheoles and to cells.

43
Q

Structure of insect

A

Spiracles- tiny holes on outer surface able to let air in and out and control water loss (use specialised muscles to control this)
Trachea- microscope air filled pipes, lined with chitin
Tracheoles- smaller tubes branched off trachea which deliver oxygen to cells and tissues

44
Q

Mammalian lungs

A
  • Supported and protected by rib cage
  • Trachea is a flexible airway covered in cartilage (walls lined with cilliated epithelium and goblet cells) which leads to lungs
  • Bronchi are two divisions of trachea, one leading to each lung
  • Made up of a series of branched tubules, branchioles which formed air sacs alveoli
  • Alveoli are lined with epithelium and have elastic fibres to return to normal shape after breathing
45
Q

Increasing rate of diffusion in humans

A
  • Alveoli have large quantity in lungs producing large SA
  • Walls are one cell thick of flat cells forming short diffusion pathway
  • Surrounded by network of capillaries creating good blood supply and increase SA
46
Q

Lung volume

A

Spirometer used to measure lung volume and diagnose lung diseases.
- A chamber filled with oxygen moving up and down with each breath

47
Q

Functions of spirometer

A

Person breathes O out of chamber and CO2 into chamber (dangerous amount exhaled, soda lime used to absorb)
Attached to lid is a pen which records movements on rotating drum to produce spirometer trace

48
Q

Tidal volume

A

Volume of air in each breath

49
Q

Forced Expiratory Volume (FEV)

A

Maximum volume of air that can be breathed out in one second

50
Q

Forced Vital Capacity (FVC)

A

Maximum volume of air that can be breathed out forcefully after a deep breath in

51
Q

Residual volume

A

Volume of air that always remains in lungs even after forced expiration

52
Q

Total lung capacity

A

Maximum volume of air that can be inhaled into lungs

53
Q

Ventilation rate

A

Number of breaths per minute

54
Q

Which side of the heart is thicker?

A

Left side is thicker as it is responsible for pumping blood to the rest of the body (contracts more powerfully)

55
Q

Septum

A

Separates the two sides of the heart
- Interatrial septum (separates atria)
- Intraventricular septum (separates ventricle)

56
Q

Factors affecting activity of enzyme

A

Enzyme concentration
Substrate concentration
pH
Temperature

57
Q

What happens to enzymes on very high temperatures?

A

The rate of reaction is increased with the increase of temperature but up to a certain limit. If the temperature is increased further, the enzyme is denatured.

58
Q

How does pH affect the activity of enzymes?

A

Every enzyme works efficiently on optimum pH. A change in the optimum pH results in the denaturation of the enzyme.

59
Q

Xylem functions

A

AQA A level Biology (6 decks)

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