3.3 Organisms exchange substances with their environment

Question 1

what is meant by surface are: volume

Answer 1

how far the internal parts are from the surface.

Question 2

what happens to the surface are:volume when an organism increases

Answer 2

the surface area:volume ratio decreases

Question 3

why can smaller organisms rely on diffusion for gas exchange but animals cant?

Answer 3

large SA:V and short diffusion pathway allowing for gas exchange to occur.

Question 4

why do animals need a specialised transport system?

Answer 4

smaller SA:V and also a longer diffusion pathway.

Question 5

how do multicellular organisms get O2?

Answer 5

specialised systems and exchange systems: circulatory + respiratory

Question 6

what do organisms exchange?

Answer 6

-urea
-O2
-CO2
-blood
-nutrients

Question 7

explain why oxygen uptake is a measure of metabolic rate in organisms?

Answer 7

oxygen is used during respiration.
the greater the O2 uptake the larger the metabolic rate increases.
larger and multicellular.

Question 8

what is the metabolic rate?

Answer 8

amount of energy expanded by an organism within a given amount of time.

Question 9

explain how larger organisms are able to adapt to cold climates?

Answer 9

less heat is lost because:
small surface area to volume ratio
large diffusion pathway

Question 10

how is the exoskeleton used to prevent water loss

Answer 10

a lipid layer
also fibrous material for protection.

Question 11

how do the spiracles prevent water loss?

Answer 11

the open and close to reduce water loss

Question 12

what enters and leaves the spiracles?

Answer 12

gases enter
water evaporates.

Question 13

how do gases enter the tracheoles via diffusion?

Answer 13

-cells respire aerobically and O2 is used up.
-concentration decreases in tracheoles.
-diffusion gradient established between atmosphere and tracheoles.
-O2 diffuses in.

Question 14

in what direction does O2 move when a diffusion gradient is established?

Answer 14

spiracles-trachea-tracheoles-cell

Question 15

how do gases move out thee spiracle via mass transport?

Answer 15

muscle cells contract
causes the mass movement of O2 and CO2

Question 16

how do gases move into tracheoles when its filled with water

Answer 16

after major activity
cells respire anaerobically
produces lactate + lowers WP
water from tracheoles move via osmosis into cells.
volume and pressure decreases draws air in

Question 17

what happens when lactate is produced during anaerobic respiration in the spiracles

Answer 17

lowers water potential

Question 18

what is an adaptation of the large no of tracheoles

Answer 18

larger surface area

Question 19

how are tracheoles useful adaptations

Answer 19

thin walls
short diffusion pathway + distance between tracheoles and spiracles

Question 20

what is the helpfulness of CO2+O2 in a fish

Answer 20

creates a steep diffusion grradient.

Question 21

what is found on the surface of the gill filaments?

Answer 21

lamellae

Question 22

what is Fick’s Law?

Answer 22

Diffusion dp surface area*diff in conc
divide by length of diffusion pathway

Question 23

why do fish have special addaptations?

Answer 23

30x less O2 inwater than atmosphere

Question 24

what do the lamelle provide?

Answer 24

larger surface area

Question 25

how is the concentration gradient maintained in a fish?

Answer 25

countercurrent flow

Question 26

how is a short diffusion pathway formed in a fish?

Answer 26

a capillary network in every lamelle thin gill lamelle

Question 27

Where is the large SA:V ratio created in a fish?

Answer 27

many gill fillaments covered by many gill lamelle

Question 28

what is the countercurrent flow?

Answer 28

blood flows in the opposite direction of water so equilibrium is not reached ensures a concentrtion gradient is established across entire length of lamelle.

Question 29

what flows in opposite direction in the countercurrent flow?

Answer 29

blood and water

Question 30

why does blood and water flow in opposite direcctions?

Answer 30

so equilibrium is not reached

Question 31

why should the equilibrium not be reached?

Answer 31

so a concentration gradient is estblished across the ENTIRE length of LAMELLE.

Question 32

what diffuses into the leaf?

Answer 32

CO2

Question 33

what diffuses out a plant cell?

Answer 33

O2

Question 34

what does the stomata do to reduce water loss in dictolydenous plants?

Answer 34

stomata closes at night

Question 35

what are xerophytes?

Answer 35

plants found in extreme temps

Question 36

how dos a smaller SA:V reduce water loss in xerophytes?

Answer 36

reduces rate of diffusion

Question 37

why do xerophytes have waxy cuticles?

Answer 37

waterproof less water escapes as its THICK

Question 38

what is the SA:V in xerophytes and how does this help with water loss?

Answer 38

reduces rate of diffuusion

Question 39

what happens when the leaves are rolled in xerophytes?

Answer 39

lower epidermis is isolated traps region of air water evaporates and air becomes saturated. WP increase in the region WP M in leaf and air decreases no evaporation

Question 40

what happens when the H2O evaporates within region of air

Answer 40

WP increase WP M decreases no evaporation

Question 41

what happens to the water potential gradient of a rolled leave?

Answer 41

it decreases WP increases in the air

Question 42

what is a useful adaptation of hairy xerophyes that prevents water loss?

Answer 42

hair traps moist layer of air WP M from leaf to trapped air decreases less water evaporates own WP M

Question 43

what is ventilation?

Answer 43

to breathe in

Question 44

where does the antagonistic interaction occur?

Answer 44

between the external and internal intercostal muscles

Question 45

what is inspiration

Answer 45

to breathe in

Question 46

what happens to the external intercostal muscles during inspiration?

Answer 46

it contracts (rib is pulled upwards)

Question 47

what happens to the internal intercostal muscles during inspiration?

Answer 47

it relaxes

Question 48

what happens to the diagraphm during inspiration?

Answer 48

contracts [n-->u]

Question 49

what happens to the air pressure in the lungs during inspiration?

Answer 49

it decreases

Question 50

what happens to the volume of the lungs during inspiration?

Answer 50

it increases

Question 51

how does air move during inspiration?

Answer 51

high pressure in the atmosphere compared to inside the lungs.

Question 52

what is expiration?

Answer 52

breathing out

Question 53

what happens to the external intercostal muscles during expiration?

Answer 53

they relax

Question 54

what happens to the internal intercostal muscles during expiration?

Answer 54

they contract

Question 55

what happens to the diaphragm during expiration?

Answer 55

it relaxes (pops back up to dome) [n->u->n]

Question 56

what happens to the pressure in the lungs during expiration?

Answer 56

it increases

Question 57

what happens to the volume of the lungs during expiration?

Answer 57

it decreases

Question 58

how does air move in during expiration?

Answer 58

moves out cause higher pressure in lungs than atmosphere.

Question 59

what variables can determine the BMR

Answer 59

CO2 production Oxygen consumption Heat generated

Question 60

why do smaller organisms have a high BMR even though they are small.

Answer 60

-they have SA:V and therefore lose heat quickly -will cool down if respiration stops -so faster heart rate is needed to supply O2 for respiration

Question 61

what is the function of a sunken stomata?

Answer 61

reduces air movement across stomata. -moist air is trapped inside.

Question 62

what is the function of a thick waxy cuticle?

Answer 62

reduces transpiration/evaporation provides a larger diffusion distance

Question 63

what is function of the hair on xerophytes?

Answer 63

traps air becoming damp/humid

Question 64

What are large insoluble molecules broken down into

Answer 64

Small soluble molecules

Question 65

what 2 enzymes break down carbohydrates?

Answer 65

amylase membrane bound dissacharidases

Question 66

where is amylase found?

Answer 66

salivary glands pancreas

Question 67

what are examples of the membrane bound dissacharidases?

Answer 67

maltase lactase sucrasse

Question 68

what do membrane bound disaccharidases break things down to?

Answer 68

from disaccharides to monosaccharides

Question 69

what is an example of the disaccharidases

Answer 69

lactase-->lactose-->glucose and galactose

Question 70

what 3 enzymes break down proteins?

Answer 70

-endopeptidases -exopeptidases -membrane bound dipeptidases

Question 71

how are proteins broken down

Answer 71

protein-->dipeptide--> amino acids

Question 72

where are the protein enzymes found

Answer 72

stomach and pancreas

Question 73

what is the role of exopeptidases?

Answer 73

enzymes that hydrolyse peptide bonds between the amino acids at the end of a polymer chain

Question 74

what is the role of endopeptidases?

Answer 74

enzymes that hydrolyse the peptide bond between amino acids at the start of a polymer/ peptide chain.

Question 75

where does the exopeptidase hydrolyse the peptide bond?

Answer 75

at the end of the polymer chain (between amino acids)

Question 76

where does the exopeptidase hydrolyse the peptide bond in the polymer

Answer 76

the end of the chain

Question 77

where does the endopeptidases hydrolyse the peptide bonds in the polymer?

Answer 77

the middle of the chain

Question 78

what is the role of a membrane bound dipeptidases?

Answer 78

hydrolyse the peptide bonds between dipeptides forming amino acids

Question 79

what enzyme hydrolyses lipids?

Answer 79

lipase

Question 80

where are bile salts produced?

Answer 80

liver

Question 81

where are bile salts stored?

Answer 81

gall bladder

Question 82

what is the role of bile salts?

Answer 82

emulsify triglycerides into monoglycerides and glycerol. forming small droplets called micelles.

Question 83

what is the role of lipase?

Answer 83

hydrolyse ester bonds in triglycerides

Question 84

what is the usefullness of the small micelle droplets?

Answer 84

increases SA faster hydrolyses action from lipase

Question 85

what does the physical breakdown of lipids involve?

Answer 85

bile salts emulsifying triglyerides

Question 86

what does the chemical breakdown of lipids invole

Answer 86

fast hydrolyses of lipase on micelle droplets

Question 87

what is the alimentary canal?

Answer 87

the places where the food passes through

Question 88

where is food absorbed?

Answer 88

small intestine (ileum)

Question 89

what is the structure o the ileum?

Answer 89

-thin walls -network of capillaries -many microvilli -villis

Question 90

why are the thin walls a useful adaptation

Answer 90

shorter diffusion pathway maintains the concentration gradient

Question 91

why are the microvillis useful adaptations?

Answer 91

increase the surface area

Question 92

what do long fatty acid chains and monoglycerides form?

Answer 92

triglycerides

Question 93

what are triglycerides packaged into?

Answer 93

chylomicrons

Question 94

where are the chylomicrons transported to?

Answer 94

lacteal

Question 95

is the lacteal?

Answer 95

lymph vessel within villius

Question 96

how does the chylomicrons leave the small intestine?

Answer 96

exocytosis