exchange and digestion Flashcards

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1
Q

where in a cell has highest CO2 conc and lowest O2 conc and why

A

mitrochondria
to maintain diffusion gradient

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2
Q

why do small and inactive organisms not require specialised gas exchange surfaces

A

they have a low surface area to volume ratio
so gas can exchange across a thin membrane

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3
Q

why do large organisms require a circulatory system

A

because of their large surface area to volume ratio

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4
Q

why do specialised exchange surfaces have large surface area to volume ratio

A

increases rate of exchange

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5
Q

why do specialised exchange surfaces have very thin membranes

A

to decreases diffusion pathway

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6
Q

why do specialised exchange surfaces have selectively permeable membrane

A

allows only certain materials across

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7
Q

why do specialised exchange surfaces have movement of environmental medium in them

A

maintain diffusion gradient

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8
Q

why do specialised exchange surfaces have movement of internal medium

A

maintain diffusion gradient

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9
Q

what is ficks law

A

diffusion = SA x conc difference /length of pathway

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10
Q

describe the relationship between size of microorganism and SA;V

A

as the size of something increases the surface area to volume ratio decreases

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11
Q

what are the two ways terrestrial insects prevent water loss

A

exchange system has a small surface area to volume ratio
waterproof covering on exposed exoskeleton

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12
Q

name the parts of an insects tracheal system

A

spiracle
trachea
muscle tissue
tracheoles

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13
Q

what happens when insects respire anaerobically

A

lactic acid is produced which is solute and lowers the water potential of water in the tracheoles
the water is then moved via osmosis from trachea to cells.
air is drawn into tracheoles creating a lower pressure to increase rate of diffusion because muscle cells are swollen so closer to tracheoles

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14
Q

how are spiracles adapted to help maintain humidity

A

body segments pull skeleton plates together
air squeezes into the sacs to limit gas exchange

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15
Q

how are spiracle hairs used to reduce water loss

A

trap water molecules which maintains the hummidity around the spiracles to reduce conc gradient so less water is lost

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16
Q

what is the function of chitin in the trachea
also what is chitin

A

nitrogen containing polysaccharide
maintain trachea shape even at low pressure

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17
Q

name the parts of a fish gill

A

gill arch
gill
operculum
operculum opening
gilll filament
lamella

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18
Q

how do fish get oxygen from the water/
describe its structure

A

water is taken in the through the mouth and passed over the gills and out the operculum
gills comprise of filaments which increase the surface area
on the fillaments are lamella which also increase surface area
counter current flow - oxygen and water flow in opposite directions to maintain conc gradient

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19
Q

why do fish die in air

A

lamella stick together in air so decrease surface area and gas exchange cant happen so quick

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20
Q

by what process does water move out of the stoma

A

diffusion

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21
Q

what are stoma

A

pores on the underside of leaves which are surrounded by guard cells which control their opening and closing

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22
Q

what are the guard cells when stoma is open

A

turgid

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23
Q

what are the guard cells when stoma is closed

A

plasmalised
because water moves down water potential gradient and into the mesophyll

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24
Q

how do plants prevent water loss

A

closing the stoma
waterproof cuticle on leaves
rolling up leaves creates a high water potential so does hairs on leaves
reduced SA:V (pines)

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25
Q

name the parts of the human exchange system

A

nasal cavity
trachea
bronchi
bronchiole
alvioli
capillaries

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26
Q

why do humans need to respire aerobically

A

to have regular supplies of oxygen to make ATP during respsiration in the mitrochondira which also produces CO2 as a waste product

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27
Q

describe the specific qualities of the trachea

A

C shaped rings of cartalige
ciliated epithelial cells which waft rythmically
smooth muscle cells
elastic tissue

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28
Q

describe the specific qualities of the bronchus

A

small sections of cartalige
ciliated epithelial cells which waft rythmically
smooth muscle cells
elastic tissue

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29
Q

describe the specific qualities of the bronchioles

A

ciliated epithelial cells which waft rythmically
smooth muscle cells - contract t control air movement in the lungs
elastic tissue

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30
Q

describe the specific qualities of the alvioli

A

squaremous epithelial cell
elastic tissue - allows them to stretch and fill with air

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31
Q

what is the difference between bronchioles and bronchus by appearance

A

bronchioles have rough felled inner surface whereas bronchus are less likely to and will have chunks of cartilage

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32
Q

in what direction does gas move

A

from an area of high pressure to low pressure

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33
Q

what is inspiration

A

air pressure inside the lungs is reduced so air moves in

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34
Q

what is expiration

A

air pressure inside lungs is increased so air moves out

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35
Q

describe the steps of inspiration

A
  1. external intercostal muscles contract
  2. internal intercostal muscles relax
  3. ribs and sternum move up and out
  4. diaphragm contacts and flattens
  5. volume of thorax increases
  6. elastic tissue of lungs os streched
  7. lunges expand
  8. pressure in lungs is reduced
  9. air is forced into alvioli
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36
Q

describe the steps of expiration

A

1.external intercostal muscles relax
2. internal intercostal muscles contract
3. ribs and sternum move down and in
4. diaphragm relaxes and returns to dom shpe
5. volume of thorax decreases
6. elastic tissue recoils
7. lung size decreases
8. pressure inside the lungs increases
9. air is forced out of the alvioli

37
Q

what is pulmonary ventilation

A

volume of air moved into the lungs in one minute

38
Q

what is ventilation rate

A

number of breaths in one minute

39
Q

what is tidal volume

A

resting breathing rate

40
Q

what is vital capacity

A

max inhale + max exhale

41
Q

what is the formula for pulmonary ventilation

A

tidal volume / ventilation rate

42
Q

what is the formula for cardiac output

A

stroke volume ( volume of blood per beat) x heart rate

43
Q

how does large surface area influence rate of gas exchange in the lungs

A

large area for diffusion so is quicker

44
Q

how does very thin walls influence rate of gas exchange in the lungs

A

short diffusion pathway so is quicker

45
Q

how does movement of medium influence rate of gas exchange in the lungs

A

maintain diffusion gradient
more movement = more diffusion

46
Q

how many cells does a gas cross from alvioli to lungs

A

2
epithelial of alveoli and capillary

47
Q

what does the line in a spirometer mean

A

down = inhale
up = exhale

48
Q

what does the line in a lung capacity graph mean

A

down = exhale
up = inhale

49
Q

what are the symptoms of pulmonary fibrosis

A

chronic dry cough
pain in chest
short breath
weakness/fatigue

50
Q

what are the causes of pulmonary fibrosis

A

pollutants ( common among minners)
ideopathic - unknown cause

51
Q

what is pulmonary fibrosis

A

scar tissue in the lungs causing less diffusion and less elasticity which causes difficulty breathing because alvioli cant recoil or fully inflate

52
Q

what are the symptoms of asthma

A

tight chest
difficulty breathing
wheezing
coughing

53
Q

what are the causes of asthma

A

family history
allergens ( fur , cold air , anxiety)

54
Q

what is asthma

A

inflamation of the linng of the bronchi
more mucus is produced
so there is a resistance to air flow and oxygen conc decreases so less diffuses into the blood

55
Q

what are the symptoms of emphysema

A

short breath
chronic cough
bluish skin colour

56
Q

what are the causes of emphysema

A

smoking

57
Q

what is emphysema

A

damage to elastin proteins ins the lungs so they loose elasticity so cant force air out or in so decreases diffusion into blood
diffusion pathway is increased because walls of alvioli are broken down

58
Q

what are the risk factors for COPD

A

smoking
air pollution
genetics
frequent infections
occupation

59
Q

what is a casual link in data

A

direct cause and effect relationship

60
Q

what are the 3 stages of the scientific process

A

establish hypothesis
design and perform experiments
establish casual link and formulate theories to explain this

61
Q

why do lipids lubricate the lungs

A

prevent alvioli being stuck together after a large inhalation

62
Q

how does the digestive system work

A

glands produce enzymes that hydrolyse macromolecules into simple molecules ready for absorption

63
Q

why are your intestines not technically part of your body

A

molecules and ions only truley enter your body when they are absorbed in the epithelial cells
your intestines are an outside environment

64
Q

what does the salivary gland do

A

secret amylase via a duct to the mouth
which catalyses the hydrolysis of starch into maltose

65
Q

what does the oesophagus do

A

carries food from the mouth to the stomach
made up of thick muscular walls

66
Q

what does the stomach do

A

inner layer produces enzymes
stores and digests food especially proteins
glands produce digestive proteins
other glands produce mucus which prevents self digestion of its own enzymes

67
Q

what does the pancreas do

A

a large gland below the stomach
secrets protease to digest proteins
lipase to digest lipids and amylase for the hydrolysis of starch

68
Q

what does the small intestine do

A

long muscular tubes where food is digested
inner walls are folded into villi for large SA and covered in micro villi
absorbs products into the bloodstream

69
Q

what does the large intestine do

A

reabsorbs water
food becomes thicker and drier making faeces

70
Q

what does the rectum do

A

faeces is stored here before being removed via egestion

71
Q

what is absorption

A

moving soluble molecules into the cell from the small intestine

72
Q

what is assimilation

A

absorbed amino acids that are used to make new proteins

73
Q

what is physical breakdown

A

breaking large food into smaller foods via chewing and muscular contractions in the stomach
to increase SA

74
Q

what is chemical breakdown

A

using enzymes to hydrolyse molecules

75
Q

name 2 membrane bound enzymes

A

sucrase and lactase

76
Q

summaries starch digestion

A

amylase
from salivary gland and pancreas
not membrane bound
makes maltose

77
Q

summaries maltose digestion

A

maltase
from the ileum
membrane bound
makes alpha glucose

78
Q

summaries sucrose digestion

A

sucrase
from the small intestine
membrane bound
makes alpha glucose and fructose

79
Q

summaries lactose digestion

A

lactase
from the ileum
membrane bound
makes alpha glucose and galactose

80
Q

summaries proteins digestion

A

endopeptidase - from the pancreas- not membrane bound - makes amino acids

exopeptidase - from pancreas - not membrane bound - makes amino acids

dipeptidase - from the ileum - membrane bound - amino acids

81
Q

summaries lipids digestion

A

lipase
from pancreas
not membrane bound
glycerol +fatty acid (monoglyceride)

82
Q

what is the role of bile salts in lipid digestion

A

emulsifies large fat droplets into small ones

83
Q

what is lactose intolerance

A

when your body doesn’t digest lactose because it cannot produce lactase

84
Q

why does lactose intolerance lead to diarrhea

A

because solutes have not been absorbed are in the faeces so the water potential is lower so cannot be drawn out in the large intestine

85
Q

How are amino acids absorbed into the blood stream

A

Co transport from ileum to epithelial cell
Facilitated diffusion through carrier proteins from epithelial cell to blood stream

86
Q

Steps of Lipid digestion

A

1 bile salts produced in the liver emulsify lipids into Micelles to increase surface area
2ester bonds in the triglycerides are hydrolysed by pancreatic lipase the fatty acids and monoglycerides produced are packaged into micelles
3micelles come into contact with epithelial cells of villi and release monoglycerides and fatty acids
4they diffuse into epithelial cells and move towards the endoplasmic reticulum where they form triglycerides
5 these triglycerides in the chlymicrons are hydrolysed and fatty acids diffuse into tissue
6 they move out of epithelial cell via exocytosis and into lacteals
7chlyomicrons move from lacteals into blood stream

87
Q

Are chlycomircons water soluble

A

Yes they can pass from lacteals to capillaries

88
Q

Describe carbohydrate digestion

A

1 saliva enters mouth from salivary gland and mixes with food during chewing
2 hydrolysis of glycosidic bonds in starch by amalayse to form maltose
3 food is swallowed and enters the stomach
4 food moves to ileum where is mixes with pancreatic amylase
5 pancreatic amylase continues hydrolysis of starch to maltose
6 epithelial lining of the ileum produces the disaccharide maltase
Which is membrane bound and hydrolysed maltose into alpha glucose
7molcules are absorbed via co transport of sodium