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--gcse subjects-- > bio sb8 > Flashcards

bio sb8 Flashcards

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1
Q

many substances diffuse in and out the body and to make sure they diffuse quick…

A

the surfaces they move through must be thin so they dont diffuse v far and have large SA so theres more room for particles to diffuse

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2
Q

whats the need for a transport
system in multicellular organisms

A

it would take too long for materials to diffuse through cells on the outside of the tissue to reach the inside

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3
Q

how are alveoli adapted for gas exchange by diffusion

A

thin walls and large surface area (for
faster diffusion)
large blood supply

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4
Q

what factors affect the rate of diffusion?

A

surface area of membrane, concentration gradient and diffusion distance

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5
Q

the rate of diffusion using Fick’s law

A

rate of diffusion is proportional to S.A x Conc difference
———————————
membrane thickness

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6
Q

how is each type of blood vessel artery, vein and capillary adapted for its function?

A

arteries - thick wall to withstand pressure

veins contain valves to stop blood flowing the
wrong way

capillaries- thin wall to allow fast diffusion

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7
Q

how is the structure of this blood cell adapted to its function?
red blood cells and white

A

red blood cells - contain haemoglobin which binds with 02.
-no nucleus, more space for haem
-biconcave shape increase SA:V ratio for oxy to diffuse in and out

lymphc - produce proteins called antibodies, which stick to pathogens
phag - engulf pathogns

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8
Q

how is the structure of plasma and platelets adapted to its function?

A

platelets - no nuclei, produces substances to clot blood
plasma - carries dissolved substances like urea and glucose

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9
Q

describe the heart blood flow.

A
  1. Blood from most the body enters right atrium through vena cava.
  2. Blood from lungs enters left atrium through pul vein
  3. When these chambers r full , muscles around them contract pushing blood into ventricles
  4. muscles in vent walls contract forcing blood out heart.
  5. mucles in atria walls relax and chambers refill with blood
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10
Q

equation for working out cardiac output?

A

C.0 = stroke volume x heart rate
litres/min = litres/beat x beats/min

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11
Q

what is respiration and why is it exothermic

A

exothermic reaction which
occurs continuously in living cells to release energy for
metabolic processes, including aerobic and anaerobic
respiration

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12
Q

describe aerobic respiration…

A

-requires oxygen , occurs in mitochondria
-glucose + oxygen ——> c02 + water
-more energy released
-happens all the time

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13
Q

describe anaerobic respiration..

A

-glucose —–> lactic acid
-used during strenuous exercise
-much less energy released
-occurs in cytoplasm
-no oxygen req

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14
Q

how are ecosystems organised?

A

-all organisms and the environment they live in form an eco system
-all organisms that live and interact in an ecosystem forms a community
- the community is made up of populations of diff species
-these species depend on each other for resources = interdependt
-each pop lives in a partic habitat within eco sys

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15
Q

how is interdependence important

A

organisms are continuously interacting with each other and their environments. Eg shelter , food

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16
Q

describe the flow of trophic levels.

A

energy stored in plant biomass is transferred to a herbivore , then transf to carnivore

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17
Q

why does a pyramid of biomass have a pyramid shape?

A

As not all energy stored in biomass in one trophic
level is transferred into biomass in the next trophic
level, (1) the levels get smaller through the food
chain/going up the pyramid.

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18
Q

how can you measure organisms in an area using quadrats or belt transects

A

quadrats are placed at random on a transect line. abundance of organisms is measured.

19
Q

what are abiotic and biotic factors?

A

ab - non living facotrs that can affect the distribution of organisms in an area. eg temp

bio- organisms in an eco system that affect other living organisms
(also links to interdependence within a community)

20
Q

scienitsts say each speccies of organisms has certain adaptations..

A

meaning the organism is adapted to certain condiotions so if abiotic factors change then the distibution of organisms may also change

21
Q

Define an indiactor species

A

organisms whose presence indicates the presence or absence of certain types of pollution

22
Q

what is polluted water often identified by?

clean water?

air quality?

A

the presence of blood worms or sludge worms (these r found in water w high pollution)

fresh water shrimps and stonefly (much lower pollution lvls)

heavy polluted = less lichen and rosespot

23
Q

benefits of indicator species for pollution?

A

-gives simple assessment of the long term health of an ecosystem
-no numerical data

24
Q

parasitism
mutualism

A

a feeding relationship in which is a parasite benefits and its host is harmed
a rs between diff individuals of species where both individuals benefit

25
Q

what is fish farming
add and disadv

A

growing fish in pens for food
more fish produced and u can reduce overfishing of wild fish
diseases spread more easily so fish must be treated to be kept healthy

26
Q

introducing new species to an ecosystem can affect the…
why may new species be introduced

A

indigenous/native species living there
controlling pests, food, zoos

27
Q

eutrophication ?
adv, disadv

A

the addition of more nutrients to an ecosystem than it already has
-fertilisers help plant crops grow better
-it will also cause the growth of other plants and algae which will affect aquatic organisms in the long run. no 02

28
Q

define conservation

A

effort is made to protect a rare or endangered species or habitat

29
Q

how can animal species be increased

A

reforestation, planting lots of trees increases the range and no. of species living in the area

30
Q

what are the benefits of being in an area with lots of biodiversity

A

-they can recover faster from disasters
- plants/animals can be used for medicine and food

31
Q

why may an animal be held in captivity

A

-they may be endangered/hunted
-theyre habitats may be not be safe or reduced due to deforestaion

32
Q

what is food security ?

A

having enough access to safe and healthy foods at all times

33
Q

Describe the biological factors affecting levels of food security,

A

a increasing human population
c the impact of new pests and pathogens
d environmental change caused by human activity

34
Q

describe the water cycle

A
  1. liquid from oceans evapourates
  2. water vapour condenses to form clouds
  3. falls as precipitation
35
Q

what is desalination
distillation

A

obtaining fresh water from the sea
water is evaporated, condensed and collected

36
Q

what are the stages of the carbon cycle

A
  1. CO2 removed from air by plants and algae during photosynthesis. they use the carbon to make proteins , carboh, and fats
  2. co2 returned when P and AL respire
  3. decomposers respire while they return mineral ions to soil
  4. co2 returned to air when wood and fossil fuels burnt (combustion)
37
Q

what is a decomposer

A

an organism that feeds on dead material causing decay

38
Q

why is nitrogen good for plants?

A

The nitrogen is needed to make
proteins and DNA. Without nitrogen
the plant cannot make more cells
and grow

39
Q

define nitrogen fixing bacteria

denitrifying bacteria

A

soil bacteria that can convert nitrogen gas into nitrogen compounds in the soil

when bacteria in the soil break down nitrates back to nitrogen gas which returns to the air

40
Q

whats crop rotation

A

planting diff crops in fields every 3-4 yrs
helps to control build up of soil pests for each crop

41
Q

whats the nitrogen cycle?

A
  1. nitrogen from air is converted to nitrates by nitrogen fixing bacteria
  2. nitrates absorbed by plants and used to make amino acids
  3. these aa then pass into animals when they eat the plants
  4. animals release waste products like urea and both plants and animals die
  5. now u have nitrogen in dead remains and waste products
  6. decomposing bacteria convert nitrogen into ammonia
  7. nitrifying bacteria converts ammonia to nitrates which are absorbed by plants.
42
Q

decomposers grow best..

methods of food preservation?

A

in warm moist conditions with oxygen

reducing o2, irridation to kill deco, reducing water and temp

43
Q

best conditions for composts :
spreading compost in a garden increases…

A

warm, o2 , moist
soil fertility

--gcse subjects-- (11 decks)

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