Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology (Year 1) > 3.3 Organisms exchange substances > Flashcards

3.3 Organisms exchange substances Flashcards

1
Q

Define surface area

A

total area over which substances and heat are exchanged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What two factors affect rate of exchange?

A
  1. size
  2. metabolic rate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What four factors influence the rate of exchange?

A
  1. temperature
  2. thickness (exchange distance)
  3. surface area
  4. concentration gradient
  5. number of protein carriers/channel proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the four main substances that organisms need to transfer?

A
  1. gases - oxygen, carbon dioxide
  2. nutrients - glucose, amino acids
  3. excretory products - urea, carbon dioxide
  4. heat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What effect does an increase in size have on the need for a specialist exchange surface in larger animals?

A
  1. as size increases, the increase in volume is disproportionate to the increase in surface area
  2. and demands for nutrient and waste removal increase
  3. so surface area isn’t large enough to satisfy the extra demands
  4. so specialised exchange surfaces are needed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What two adaptations do multicellular organisms have to carry out exchange?
- give examples

A
  1. transport systems - circulatory, respiratory
  2. specialialised exchange surfaces - alveoli, tracheoles, gill filaments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the relationship between SA:V and size of an organism?

A

as size INCREASES, SA:V DECREASES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the relationship between SA:V and metabolic rate?

A
  • smaller animals have a larger SA:V
  • so they lose more heat
  • so have a **higher metabolic rate **
  • to maintain body temp
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the relationship between shape of an organism and heat exchange?

example?

A
  • more compact shape
  • means a **smaller SA:V **
  • minimising hear loss

the arctic fox has small ears and a round head, while african fox has large ears and a pointed nose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why is it important that oxygen and carbon dioxide can be exchanged effectively?

A
  1. Oxygen - needed for the production of ATP in aerobic respiration
  2. Carbon dioxide - produced in aerobic respiration, needs to be removed as it is toxic and build up can change cell pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the four main features of an effective exchange surface?
- why are these needed?

A
  1. thin - short diffusion distance
  2. large SA:V - sufficient exchange surface
  3. movement of internal/environmental mediums - maintains concentration gradient
  4. selectively permeable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do single celled organisms exchange gas?

A
  • via diffusion
  • due to their large surface area to volume ratio
  • and short diffusion pathway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Explain why single celled organisms do not require a circulatory system to maintain their metabolism?

A
  1. large surface area to volume ratio
  2. short diffusion pathway
  3. so rate of diffusion is high
  4. diffusion is sufficient to allow oxygen deep enough into the area required for respiration
  5. removal of carbon dioxide is rapid enough to prevent toxicity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What features do insects have to prevent water loss?

A
  1. waterproof cuticle covering a rigid exoskeleton
  2. spiricles can open/close
  3. spiracle hairs trap water molecules and reduce the water potential gradient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the main components of an insect tracheal system?

A
  1. spiracle - has a valve so gases can enter and leave
  2. trachea - windpipe of the insect, lined with chitin to prevent collapse
  3. tracheoles - extent through all tissues to deliver oxygen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the three ways insects use to move gases into the tracheal system?

A
  1. mass transport - abdominal muscles contract and relax to push air in and out
  2. diffusion gradient - oxygen is used up in respiration so concentration decreases, causes oxygen to diffuse from the atmosphere into the trachea
  3. water movement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe and explain what happens to the water in the tracheoles when an insect is flying?

A
  1. muscle cells respire anaerobically which produced lactate
  2. lactate is soluble to lowers the water potential in muscle cells
  3. water (from the tracheoles) moves into the cells via osmosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why does the movement of water into muscle cells increase the rate of diffusion of oxygen from the tracheoles into the muscle tissue

A
  1. decreases the volume of water in the tracheoles
  2. which draws air into the trachea
    3.** gaseous diffusion pathway is faster** so rate of diffusion increases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does the presence of spiracle hairs help to reduce the rate of water loss from the opening?

A
  1. they trap water molecules around the opening
  2. maintaining a higher concentration of water
  3. reducing the water potential gradient between the inside of the trachea and the environment
  4. reducing the rate of diffusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Explain how abdominal pumping moves gases into the tracheal system of a locust?

A
  1. increases the volume
  2. which decreases the pressure
  3. causing air to be drawn in
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What adaptations does the tracheal system have for efficient diffusion?

A
  1. lots of fine tracheoles increase surface area
  2. thin tracheole wall creates a short diffusion pathway
  3. movement of oxygen and carbon dioxide in and out maintains a steep concentration gradient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe what happens to the concentration of oxygen in the trachea when the spiracles are closed?

A
  1. oxygen concentration decreases
  2. as the remaining oxygen in the tracheoles is being used in aerobic respiration
  3. for production of ATP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What causes the spiracles to open?

A
  1. spiracles detect a high concenration of carbon dioxide in the tracheoles
  2. carbon dioxide is toxic
  3. so spiracles open to release it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What would happen to the ventilation rate in a locust if the carbon dioxide concentration was increased?

A
  1. it would increase
  2. as there is a reduced oxygen concentration
  3. oxygen is needed for aerobic respiration - production of ATP
  4. so **ventilation rate increased to increase rate of diffusion of oxygen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the function of the paliside mesophyll?

A

contains chloroplasts for photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the function of the spongy mesophyll?

A

contains large spaces which increase the surface area (so more mesophyll cells are in contact with gases) and create a short diffusion distance
- for rapid diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Describe the mechanism of diffusion in a leaf

A
  1. if enough water is present, guard cell becomes turgid - stoma opens and air can enter
  2. air spaces allow carbon dioxide to diffuse into the cells
  3. carbon dioxide is used up in photosynthesis which maintains the concentration gradient
  4. ventilation is passive as the stomata and thinness of the leaf provides a short diffusion pathway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How does the net movement of oxygen and carbon dioxide change during the day vs the night?

A

Day - Net carbon dioxide IN and net oxygen OUT
Night - net carbon dioxide OUT and net oxygen IN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What causes the stomata to close?

A
  • if the guard cells lose water and become flaccid
  • they are less rigid and move together, closing the stomata
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the compensation point and when does this occur in plants?

A

no net gas exchange, occurs at dawn and dusk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What adaptations do normal plants have for rapid diffusion?

A
  1. many stomata - short diffusion pathway (no cell is far from the stoma)
  2. air spaces in the mesophyll - gases are in contact with mesophyll cells (diffusion occurs in the gas phase which is faster than in water)
  3. mesophyll cells - have a large surface area
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What adaptations do insects have to prevent water loss?
How does the insect maintain a high level of gas exchange despite these features?

A
  1. small surface area to volume ratio - minimises area over which water can be lost
  2. rigid outer skeleton with a waterproof cuticle - prevents water loss
  3. spiracles can close
  • tracheae carry air oxygen directly to the tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What adaptations do terrestrial plants have to reduce water loss while also exchanging gases?

A
  1. waxy cuticle - waterproof to prevent evaporation from leaf surface
  2. many stomata - increases area for gas exchange but can also close to prevent excess water loss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What adaptations do XEROPHYTES have to live in areas where water is in short supply?

A

1. Thick cuticle - less water escapes
2. Rolling leaves - traps air, becomes saturated with water vapour,** lower water potential gradient** (between inside and outside of leaf) so less water loss
- also** protects the stomata from wind which increases rate of transpiration
3. Hairy leaves **- trap moist air around the stomata to lower the water potential gradient
4. Stomata in pits - traps still, moist air
5. Small, circular leaves - reduces surface area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Why is water uptake in a plant slower in the salt marsh habitat?

A
  1. water potential of the plant is higher than the salt marsh
  2. so it is harder for the root hairs to draw up water via osmosis
36
Q

Why do plants in colder climates often have smaller leaf areas?

A
  1. rate of photosynthesis is lower
  2. so there is a reduced need for light
37
Q

Why is the volume of gases exchanged by large organisms high?

A
  1. larger volume of living cells
  2. need to maintain body temperature - requires high metabolic and respiratory rates (ATP production requires oxygen)
38
Q

What are the key components of the human gas exchange system?

A
  1. nasal cavity
  2. trachea
  3. bronchus
  4. bronchioles
  5. alveoli
39
Q

Describe how the structure of the trachea is related to its function?

A

1.** rings of cartilage** - hold trachea open while allowing some flex (to allow food down esophagus)
2. **cilated epithelial cells **- cilia sweep mucus into stomach
3. goblet cells - produce mucus (traps dirt and microorganisms0

40
Q

Describe how the structure of the bronchi is related to its function?

A
  1. cilia and goblet cells - produce mucus and waft it to the stomach
  2. cartilage - supports the bronchi
41
Q

Describe how the structure of the bronchioles are related to their function

A

1.** smooth muscle lined with epithelial cells** - allows constriction and dilation to control the airflow in and out the alveoli

42
Q

Describe how the structure of the alveoli are related to their function

A
  1. collagen and elastic fibres - allow alveoli to stretch during inspiration and recoil during expiration
  2. single layer of flattened epithelium cells - thin and permeable for easy diffusion of gases
  3. capilliary network - thin, so only one red blood cell can pass at a time, allowing gas exhange to occur fully
43
Q
A
44
Q

Describe the structure of fish gills?

A
  1. series of GILLS on the side of the head
    2.** gill arch** - attached to gill fillaments
  2. rows of** lamellae** on each fillament
45
Q

Adaptations of fish gills for efficient gas exchange

A
  1. **thin lamellae and capillary network **- short diffusion pathway
  2. **Effective ventlilation and countercurrent flow **- maintains the concentration gradient
  3. lamellae and gill filaments - create a large surface area for maximum gas exchange
46
Q

How is water passed along fish gills?

A
  1. water passes in through the mouth
  2. passed over the gills
  3. out the operculum
47
Q

How does concentration of oxygen in water compare to blood?

A

concentration of oxygen in water is ALWAYS SLIGHTLY HIGHER than the concentration in blood

48
Q

Describe the mechanism of parallel flow?

A
  1. blood and water** flow in the same direction**
  2. so the diffusion gradient is only at the first part of the fillament
  3. no net diffusion once concentrations equilibrate at 80%
49
Q

Describe the mechanism of countercurrent flow?

A
  1. water and blood flow in **opposite directions **
  2. water has a** HIGHER oxygen concentration** than blood
    3.** concentration gradient** is maintained the entire wayalong the lamellae
  3. so oxygen is constantly absorbed by diffusion
50
Q

’

Define inspiration

A

breathing in
- air pressure inside the lungs is reduced to lower than atmospheric pressure so air moves into the lungs

51
Q

Define expiration

A

breathing out
- air pressure inside the lungs is increased to above atmospheric pressure so air moves out the lungs

52
Q

Describe the mechanism of inspiration

A
  1. external intercostal muslces contract
  2. internal intercostal muscles relax
    3.** diaphragm contracts and flattens**
    4.** volume of thorax is increased**
  3. elastic tissue in the lungs is stretched
  4. lungs expand to fill the thoric cavity - volume increases
    7.** pressure inside the lungs is reduced** lower than atmospheric pressure
  5. so air is forced down the pressure gradient**into the alveoli

ACTIVE PROCESS - energy from ATP to make the diapragm contract and flatten

53
Q

Describe the mechanism of expiration

A

1.** internal intercostal muscles contract**
2. external intercostal muscles relax
3. diapragm relaxes (moves up) and returns to its original dome shape
4. volume of thorax is reduced
5. elastic tissue in the lungs recoils
6. lung volume is reduced **
7.pressure inside the lungs is increased** to above atmospheric pressure
8.so air is forced down the pressure gradient into the atmosphere

PASSIVE - recoil of elastic tisse forces air out

54
Q

Define pulmonary ventilation

A

total volume of air moved into the lungs in one minute (dm^3 min-1)

55
Q

Define ventilation rate

A

number of breaths that occur in one minute (min -1)

56
Q

Define tidal volume

A

the volume of air taken in at each breath during rest

57
Q

Define total capacity

A

total volume of air contained in the lungs at the end of a maximun inhalation

58
Q

Define vital capacity

A

maximum volume of air a person can expel after a maximum inhalation (in one breath)

59
Q

Define residual volume

A

volume of gas remaining in the lungs at the end of the maximun exhalation

60
Q

What is the equation for pulmonary ventilation?

A

tidal volume (dm^3) x ventilation rate (min-1)

61
Q

What does a spirometer show?

A

the volume changes in the lungs

62
Q

How are the alveoli adapted for rapid diffusion

A
  1. many alveoli - large surface area
  2. alveolar epithelium and capillary endothelium have thin walls - short diffusion distance
  3. extensive capillary network - maintains the concentration gradient
  4. distance between alveolar air and red blood cell is reduced as the capillaries are narrow so red blood cells are flattened against the capillary walls
63
Q

What is pulmonary fibrosis and how does it impact gas exchange and ventilation?

A

scar tissue on lungs (caused by infection or dust) - thicker and less elastic
- elasticity decreases
- tidal volume decreases
- reduced gaseous exchange (thicker membrane = slower diffusion)
- ventilation rate increases to get enough air into the lungs

Tidal volume - total air contained in the lungs after max inhalation

64
Q

What is asthma and how does it impact gas exchange and ventilation?

A

bronchi/bronchioles become inflamed
- smooth muscle contracts and excess mucus is produced
- airways are constricted - reduced lumen diameter
- airflow is reduced so reduced volume of oxygen enters the alveoli
- reduced concentration gradient so less oxygen enters the blood

65
Q

What is emphysema and how does impact gas exchange and ventilation?

A

foreign particles trapped in alveoli - causes inflammation
- elastin breaks down - reduced stretch and recoil
- alveoli walls destroyed - reduced surface area
- rate of gaseous exchange decreases - less oxygen

66
Q

What symptom is shared by all COPD?

A
  • reduced rate of gas exchange
  • less oxygen diffuses into bloodstream
  • body cells receive less oxygen
  • rate of aerobic respiration reduced
  • less energy - TIREDNESS AND FATIGUE
67
Q

What three steps should be used when analysing data on lung disease?

A
  • start with zero
  • look for the general trend
  • overall conclusion
    (remember: correlation DOES NOT mean causation)
68
Q

Define digestion

A

large, insoluble molecules are hydrolysed into smaller more soluble molecules - to provide energy and build molecules (for growth and repair)

69
Q

Describe carbohydrate digestion and state the enzymes involved

A

1.MOUTH- amylase (in saliva) hydrolyses starch into maltose **
2. food is swallowed and enters the stomach - stomach acids denatures amylase - prevents further starch hydrolysis
3. food is passed to small intestine and mixed with pancreatic amylase - any final starch is hydrolysed
4. SMALL INTESTINE -maltase (membrane bound disaccharide) **hydrolyses maltose into alpha glucose
5. glucose can then be absorbed into the small intestine epithelial cells

70
Q

How are the epithelial cells adapted for glucose absorption

A

-many microvilli which increase surface area
- increases the number of membrane bound disaccharides
- so more maltose can be hydrolysed into glucose for absorption

71
Q

Where is amylase produced?

A

salivary glands and pancreas

72
Q

Where is amylase released?

A

mouth and small intestine

73
Q

Where is maltase produced and released?

A

part of the cell surface membrane of the epithelial cells
(membrane bound disaccharide)

74
Q

What is lactose intolerance?

A

body cannot produce lactase so cannot hydrolyse lactose - undigested lactose is hydrolysed by microorganisms in the large intestine resulting in a lot of gas and small soluble molecules
- soluble molecules lower the water potential in colon

75
Q

Describe protein digestion and state the enzymes involved

A
  1. STOMACH -** endopeptidase** hydrolyses peptide bond IN proteins
  2. partially digested food moves to the small intestine
  3. SMALL INTESTINE - more endopeptidases, and exopeptidases - hydrolyse peptide bond at the END of the chain - Dipeptides
  4. Dipeptidases - hydrolyse dipeptides into amino acids
76
Q

Where are endopeptidases produced?

A

stomach and pancreas (pancreatic juice)

77
Q

Where are endopeptidases released?

A

stomach AND small intestine

78
Q

Where are exopeptidases released?

A

pancreas (contained in pancreatic juice)

79
Q

Where are dipeptidases produced and released?

A

small intestine (cell surface membrane of epithelial cells)

80
Q

Why are endopeptidases released first in digestion and why are they initially inactive?

A
  • produce short polypeptide chains so there are more ends for exopeptidase action
  • inactive when secreted so they don’t digest surrounding cells (which are mostly made of protein)
81
Q

Describe lipid digestion and state the enzymes involved

A
  1. **Bile salts **emulsify lipids into small droplets - greater surface area for lipase action
  2. **lipase **hydrolyses the ester bonds in lipid droplets
  3. monoglycerides and fatty acids remain which the bile salts to form **micelles **ready for absorption
82
Q

Where is lipase produced?

A

pancreas

83
Q

Where is lipase released?

A

small intestine

84
Q

Describe and explain how** amino acids and monosacharides** are absorbed across the ileum epithelium?

A
  1. active transport of sodium ions OUT the epithelium cell (sodium potassium pump)
  2. **facilitated diffusion **of sodium ions down the concentration gradient into the cell
  3. **CO-TRANSPORT **- amino acid/glucose is transported in alongside the sodium
  4. facilitated diffusion (amino acid channel protein) - amino acids diffuse across the epithelium into the capillaries (down the conc gradient)
85
Q

Describe and explain how lipids are absorbed into the bloodstream?

A
  1. monoglycerides and fatty acids associate with bile salts** (Micelles)**
  2. micelles make contact with epithelial cells
  3. micelles break down and release components
  4. monoglycerides and fatty acids are non-polar so can** diffuse into the epithelial cells**
  5. transported to the** endoplasmic reticulum **where they recombine to form triglyerides
  6. triglycerides move to the **golgi apparatus **- associate with cholesterol and lipoproteins to form chylomicrons
  7. chylocmicrons move out epithelial cells via exocytosis - enter lacteals
  8. chylomicrons pass from lacteal into bloodstream
  9. triglycerides are **hydrolysed by endothelial enzymes and diffuse into tissue cells **

Biology (Year 1) (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions