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bio test 12 sep > 7.4 > Flashcards

7.4 Flashcards

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Biology 101 flashcards
1
Q

Community

A

all the populations of different species living in the same place (habitat) at the same time

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2
Q

Ecosystem

A

a community, plus all the non-living (abiotic) conditions of their environment.
Ecosystems are dynamic systems
can range in size from very small to very large

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3
Q

Niche

A

the role of a species within its habitat,

e.g. what it eats, where and when it feeds.
Each species has its own unique niche
if two species try to occupy the same niche, one will outcompete the other

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4
Q

Abiotic conditions

A

the non-living features of the ecosystem
e.g. temperature, pH

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5
Q

Biotic conditions

A

the living features of the ecosystem
e.g. predation, food supply, disease

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6
Q

Carrying capacity

A

maximum stable population size an ecosystem can support
varies as a result of the effect of abiotic fators and interactions between organisms (interspecific competition, intraspecific competition, predation)

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7
Q

What factors influence carrying capacity?

A

Abiotic factors
e.g. light, water, temperature
organisms grow fast and reproduce successfully with ideal abiotic conditions for the species
Interactions between organisms
Interspecific competition
Intraspecific competition
Predation

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8
Q

How does interspecific competition influence population size/carrying capacity?

A

Competition between species
Reduces resources available to both so limits both populations
If one species is better adapted, it will out-compete the others (competitive exclusion principle - no two species can occupy the same niche)

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9
Q

How does intraspecific competition influence population size/carrying capacity?

A

competition within a species
determines population size based on resources available
Smaller population = less competition –> better for growth and reproduction

–> larger population = more competition –> less growth and reproduction –> smaller population

so causes a cyclical change around the carrying capacity

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10
Q

How does predation influence population size of predators and prey?
Describe what the graph shows

A

prey population is large:
lots of food available for predators
so predators reproduce more successfully
predator population increases
prey population decreases as they are consumed
so fewer left to reproduce
prey population is now small
less food available for predators due to small prey population
so less successful reproduction of predators
so predator population decreases
prey population increases as there are fewer predators
so cycle continues
lag between predator and prey cycles due to time taken to reproduce

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11
Q

What 2 methods could be used for estimating the population size of a slow-moving or non-motile species?

A

randomly placed quadrats
quadrats along a belt transect

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12
Q

Describe how to use randomly placed quadrats to estimate the population size of a slow-moving/non-motile species.

A

Use a grid / split area into squares
Obtain random coordinates using a random number generator – place quadrats here
Deciding the number of quadrats to use to collect representative data:
Calculate running mean
When enough quadrats, this shows little change
Count frequency of species in quadrat
Calculate mean per quadrat
Calculate population size by multiplying the mean by the number of quadrats that would cover the habitat

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13
Q

Describe how to use quadrats along a belt transect to investigate the distribution of a species.

A

Lay tape measure from one place to another
Place quadrats at regular intervals along the line
Count frequency / percentage cover in quadrats

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14
Q

What method would be used to estimate the population size of a motile species?

A

mark-release-recapture

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15
Q

Method for mark-release-recapture.

A

Capture sample of species, mark (harmlessly) and release
Leave enough time for organisms to randomly distribute before collecting second sample

  • population size= number in sample 1x number in sample 2/ number marked in sample 2
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16
Q

Assumptions made when using mark-release-recapture.

A

Sufficient time for marked individuals to mix within the population
Marking not removed and doesn’t affect chances of survival e.g. more visible to predators
No immigration/emigration
No births/deaths/breeding

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17
Q

Process of primary succession.

A

Colonisation by pioneer species (pioneer species = first species to colonise)
Pioneer species (or generally just certain species at each stage in succession) change the abiotic conditions and make the environment less hostile e.g. die and decompose, forming soil which retains water
Larger number and greater variety of niches so environment becomes more suitable for other species with different adaptations
and may be less suitable for the previous species – better adapted species outcompetes previous species
As succession goes on, biodiversity increases
Climax community: final, complex, stable community

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18
Q

pioneer species

A

first species to colonise

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19
Q

Succession

A

Process by which an ecosystem changes over time

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20
Q

Secondary succession description

A

recolonisation of an area after an earlier community has been removed or destroyed
soil and possibly seeds present
succession happens more rapidly
pioneer species are larger plants

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21
Q

How might the conservation of habitats involve management of succession?

A

Human activities can prevent succession and stop a climax community forming: plagioclimax
Conservation sometimes involves preventing succession in order to preserve an ecosystem in its current stage of succession

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22
Q

Population

A

a group of organisms of the same species, living in the same area at the same time

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23
Q

% saturated of haemoglobin with o2 equation

A

oxygenated haemboin/ maximin saturation x100

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24
Q

changing shape of haemoglobin

A

Lowe pp of 02
little increase in saturation
02 increases
rapid rise as easier for 02 to bind

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25
Q

curve shifts to right

A

lower affinity of 02

more o2 un loaded at respire g cells

more respiration

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26
Q

Different organisms have differnt types of HB

A
  • different affintiys of 02
27
Q

effect of CO2 on graph

A
  • high Pco2 - lowers HB affintiy for O2
  • rate of unloading of O2 increases at respirng cells - produces Co2
  • faster respiration - more O2 unloading for given Po2
    graph shifts to right
28
Q

graph shifts to right

A

high Pco2

HB has lower affintiy of O2 - HB less saturated at Pco2

  • Bohr shift
29
Q

haemoglobin low affinity

A

Low affinity of o2 = more o2 unloaded= rapid respiration

30
Q

Haemoglobin structure

A

Large protein with quateriary strucutre

globular protein

4 polypeptide chain - each chain has haem group - binds to 02

holds x4 molecules of O2

31
Q

HBs affintiy for O2

A

high affintiy - 02 binds easily to haem group in hb - depends on Po2

32
Q

high conc of co2

A

high repsiration

33
Q

increase partial presusre of co2 on bohr effect

A

reduceses 02 loading into blood

34
Q

larger increase of haemgoibn

A

more 02 carried

35
Q

load of O2

A

binding O2 to haemabloin (lungs)

36
Q

low O2 envrionement (allttitude) affect on haemaglobin

A
  • high affintiy for 02
  • loads easily
  • HB more satursated for given Po2
  • Shifts to left
37
Q

O2 loads onto…

A

Hb - high Po2
- lungs

38
Q

Oxygen binding to haemaglobin

A
39
Q

O2 unloads from…

A

oxyhaemaglobin - low Po2

  • repsiring tissues
40
Q

oxygen disssolcation curve explained

A
41
Q

Oxyhaemablin dissociation curve

A
42
Q

Partial pressure of Co2

A
  • measure of concentration of CO2
43
Q

Partial pressure of O2

A

Po2

  • low respiring cells
  • high lungs
  • measure of concentration of 02
44
Q

reduces partial pressure of co2

A

increases o2 loads of blood

45
Q

takes in 02

A

higher affintiy

46
Q

unloads of O2

A

unbinbind of O2 to hamebaboin ( respiring tissues)

47
Q

Very actibe/ high metablic rate organisms affect on haemaglobin

A
  • Hb low affinity of O2
  • O2 unloads rapidly
  • increase rate respiration
  • Hb less saturated at Po2
  • curve right
48
Q

Define saturation of haemoglobin

A

when all four oxygen-binding sites are occupied with oxygen in haemoglobin

49
Q

Describe and explain how a mouse’s haemoglobin would differ to a humans haemoglobin.

A

Mouse has a large SA:Vol so loses heat easily
Compensates for heat loss with a high rate of respiration
More oxygen needed for higher rates of respiration
so oxygen unloads more easily
Mouse’s Hb has a lower affinity for oxygen than human’s Hb
Oxygen dissociation curve shifted more to right than human’s Hb curve

50
Q

Describe the behaviour of haemoglobin and oxygen at respiring tissue (e.g. muscle).

A

partial pressure of oxygen (pO2) is low (oxygen concentration is low)
Haemoglobin has a low affinity for oxygen (as pO2 is low)
So oxygen readily unloads/dissociates from haemoglobin
carbon dioxide concentration is high, increasing the rate of unloading (Bohr effect)

51
Q

Describe the behaviour of haemoglobin and oxygen at the gas exchange surface (lungs).

A

partial pressure of oxygen (pO2) is high (oxygen concentration is high)
carbon dioxide concentration is low
Haemoglobin has a high affinity for oxygen (as pO2 is high)
So oxygen readily loads/associates with haemoglobin

52
Q

Describe the Bohr effect.

A

the greater the CO2 concentration the more readily the haemoglobin releases its oxygen

53
Q

Describe the effects of high CO2 concentration on haemoglobin.

A

When rate of respiration is high e.g. during exercise → releases CO2
High pCO2 lowers pH (as CO2 is acidic)
reduces haemoglobin’s affinity for oxygen as haemoglobin changes shape
Increases rate of oxygen unloading
Advantageous because provides more oxygen for muscles/tissues for aerobic respiration
Oxygen dissociation curve for haemoglobin shifts to the right

54
Q

Draw and describe the shape of the oxygen dissociation curve.

A

s-shaped
haemoglobin has a low affinity for oxygen as the 1st oxygen molecule binds
haemoglobin has a higher affinity for oxygen for the 2nd and 3rd molecule
haemoglobin has a lower affinity for oxygen for the 4th molecule
so at a low and high partial pressure the rate increase in percentage saturation is low/decreases
but at medium partial pressure, there is a high rate increase in percentage saturation

55
Q

Explain the shape of the oxygen dissocation curve.

A

At low pO2, Hb subunits are closely united, difficult for first O2 to bind.
Binding of first O2 molecule induces a change in quaternary stucture of Hb so it is easier for the other subunits to bind to O2
So smaller increase in pO2 needed for the 2nd and third O2 to bind compared to the 1st (positive cooperativity)
It is difficult for the last O2 to bind as there is a lower probability of pO2 finding the single empty binding site

56
Q

Describe the advantage of the Bohr effect during intense exercise.

A

Increases dissociation of oxygen;

For aerobic respiration at the tissues

Less lactate at the tissues

57
Q

Describe and explain the effect of increasing carbon dioxide concentration on the dissociation of oxyhaemoglobin.

A

more oxygen dissociation/ unloading

Deceases haemoglobin’s affinity for O2;

decreasing (blood) pH

58
Q

Binding of one molecule of oxygen to haemoglobin makes it easier for a second oxygen molecule to bind.
Explain why.

A

Binding of first oxygen changes tertiary and quaternary (structure) of haemoglobin;

leads to / uncovers second another binding site

Uncovers another iron / Fe / haem group to bind to;

59
Q

Describe how the structure of haemoglobin makes it effective in the transport of oxygen (4/6)

A
  1. quaternary structure
  2. haem group binds oxygen
  3. four polypeptide chains so four haem groups
  4. one haemoglobin molecule can bind 4 oxygen molecules
  5. reference to allosteric effect/ cooperative binding
  6. reference to Bohr effect/ oxygen release on binding hydrogen ions
60
Q

Explain how oxygen is loaded, transported and unloaded in the blood (6/7)

A
  1. haemoglobin carries oxygen/ has high affinity for oxygen
  2. loading/ uptake in the lungs
  3. at high partial pressure of oxygen
  4. unloads/ dissociates/ releases oxygen at respiring cells/tissues
  5. at low partial pressures of oxygen
  6. unloading linked to higher CO2 concentration at respiring tissues
61
Q

The blood leaving a muscle has a lower pH than the blood entering it. During vigorous exercise, the fall in pH is even greater. Explain what causes this greater fall in pH (4/5)

A
  1. in exercise there is a faster respiration rate
  2. more CO2 produced
  3. CO2 is acidic/ forms carbonic acid
  4. lactic acid production
  5. release of H+ ions = fall in pH (becomes more acidic)
62
Q

Describe how haemoglobin is involved i absorbing oxygen in the lungs and transporting it to respiring tissues (6/9)

A
  1. diffusion of oxygen into red blood cells
  2. haemoglobin has high affinity for oxygen where there is a high O2 concentration
  3. therefore loads/ becomes saturated in lungs/ where oxygen is abundant
  4. oxyhaemoglobin formed
  5. reference to the role of haem
  6. unload/ low affinity in low oxygen concentrations
  7. explanation of dissociation curve
  8. respiration at tissues gives high Co2 concentration
  9. dissociation curve shifts to the right
63
Q

There is an advantage to the shrew in having haemoglobin with a dissociation curve shifted to the right. Explain this advantage (5)

A
  1. at the tissues with a low partial pressure of oxygen the shrews haemoglobin is less saturated with oxygen
  2. has reduced affinity
  3. oxyhaemoglobin dissociates more readily
  4. more oxygen released
  5. allowing the shrew to meet the greater respiration demand/rate
64
Q

Succession occurs in natural ecosystems. Describe and explain how succession occurs.

A

(Colonisation by) pioneer species;
Pioneers/species/organisms change the environment/habitat/conditions/factors;
Accept example of change e.g. forms soil/humus/organic matter/nutrients.
Must convey idea of change being caused by pioneers/species/organisms
(Environment becomes) less hostile for other/new species
OR
(Environment becomes) more suitable for other/new species
OR
(Environment becomes) less suitable for previous species;
Accept previous species out-competed.
Change/increase in diversity/biodiversity;
4

bio test 12 sep (1 decks)

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