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A level biology > not yet assessed > Flashcards

not yet assessed Flashcards

didn't come up in paper 1 or 2

1
Q

outline the composition of the trachea in the mammalian gas exchange system, relating to its functions. (2)

A
  • incomplete rings of cartilage: provides structural strength
  • ciliated epithelium: goblet cells secreting mucus to trapped unwanted particles/pathogens
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2
Q

outline the composition of the bronchi in the mammalian gas exchange system, relating to its functions (2)

A
  • small incomplete cartilage rings: support/structure
  • smooth muscle: enables widening/narrowing to adapt to changing volumes of air
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3
Q

outline the composition of the bronchioles in the mammalian gas exchange system, relating to its functions (1)

A
  • smooth muscle: regulates air flow by widening/narrowing
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4
Q

outline the composition of the alveoli, and its adaptations relating to its functions.
(5)

A
  • elastic muscle: elastic recoil of lungs to force air out
  • layers of flattened ciliated epithelial cells
  • rich blood supply= rich o2 supply
  • small but large in numbers= large s.a. for gas exchange
  • thin walled= short diffusion dist
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5
Q

outline the order of structures air moves through in the insect gas exchange system.

A

1) air enters through spiracles
2) down tracheae
3) through tracheoles
4) tracheal fluid

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6
Q

outline the adaptations present in an insects gaseous exchange system

A
  • tracheae have rings of chitin
  • large number of tracheoles
  • air sacs that act as reservoirs- inflated and deflated w/ abdominal movements
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7
Q

outline how air is pumped into an insects gaseous exchange system, referring to volume changes

A
  • air is actively pumped into system by muscular pumping movements of thorax & abdomen
  • these movements increase vol & decrease pressure (air moves in)
  • or these movements decrease vol and increase pressure (air forced out)
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8
Q

outline the general structure of the gaseous exchange system in bony fish. outline some of their adaptations

A
  • gill filaments in stacks- tips of adjacent filaments overlap which + resistance to flow of water & slows movement :. increasing gas exchange time
  • lamellae: which have rich blood supply & large SA
  • water flows over gills which are covered by operculum (flap)
  • countercurrent exchange system
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9
Q

outline how to dissect a fish to view the gill filaments properly
(2)

A
  1. cut off operculum (can now see gill arch)
  2. cut out one gill filament out of 4 : can count n/of gill filaments
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10
Q

outline how to view an insects gaseous exchange system by dissecting a locus (6 steps)

A
  1. secure onto surface using pin
  2. pull out abdomen as far as it will stretch & pin
  3. remove limbs & wings
  4. cut along both sides of abdominal wall using forceps & scissors
  5. pull back flap of abdominal wall & remove
  6. submerge remains in saline solution
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11
Q

what is the light band in myofibrils
Do they change during contraction, if so how?

A

where actin and myosin don’t overlap.
also known as I bands
- the light band narrows, because the actin and myosin overlap more

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12
Q

what is the dark band in myofibrils
Do they change during contraction, if so how?

A

where the actin and myosin overlap
- remains the same width during contraction

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13
Q

what is the Z line in myofibrils
do they change during contraction, if so how?

A

darker line found at the centre of each light band
the Z lines move closer together, because the light bands narrow

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14
Q

what is the H zone in myofibrils
do they change during contraction, if so how?

A

the H zone is a lighter coloured region found at the centre of each dark band
the H zone narrows because the muscles become more compacted

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15
Q

outline the structure of myosin
(3)

A

long rod fibres with globular heads
the heads contain a binding site for each actin & ATP
the heads of the myosin protrude from all the tails wrapping around each other to form the filament

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16
Q

outline the structure of actin
(30

A

2 strands twisted round one another
actin filaments contain binding sites for the myosin heads- but these binding sites are often blocked by tropomyosin

17
Q

outline what happens in the myofibrils when a muscle is stimulated to contract
(4)

A
  • the myosin heads form bonds with the actin filaments- actin myosin cross bridges
  • the myosin heads then flex (change angle) all together, pulling the actin filament along the myosin filament
  • myosin then detaches and unflexes (using ATP)
  • myosin then reaches further up along actin filament & repeats
18
Q

outline the characteristics of skeletal muscle (4)

A
  • striated
  • voluntary
  • regular arrangement
  • short & rapid contractions
19
Q

outline the characteristics of cardiac muscle (4)

A
  • striated
  • involuntary
  • branched & interconnected
  • medium length & med strength contractions
20
Q

outline the characteristics of involuntary muscle (4)

A
  • non striated
  • involuntary
  • no regular arrangement
  • slow and long contractions
21
Q

explain how an action potential is created in a pacinian corpuscle

A
  1. pressure applied to pc
  2. corpuscle changes shape, causes membrane to change shape & stretch mediated sodium channels open
  3. influx of sodium ions into neurone
  4. membrane is depolarised, causing a generator potential
  5. generator potential creates an action potential that passes along sensory neurone
22
Q

give the formula for the element ammonia

A

NH3

23
Q

give the formula of methane

A

CH4

24
Q

give the formula of ammonium ions, and outline their function

A

+
NH
4

production of nitrate ions

25
Q

give the formula of hydrogen carbonate ions, and outline their function

A

–
HCO
3

maintenance of blood PH

26
Q

give the formula of phosphate ions, and outline their function

A

3+
PO
4

formation of cell membranes

27
Q

state the elements present in the following biological molecules:
1. carbohydrates
2. lipids
3. proteins
4. nucleic acids

A
  1. CHO
  2. CHO
  3. CHONS
  4. CHONP
28
Q

state what bonds are found in each level of protein structure

A

primary-
only peptide

secondary-
hydrogen bonds- pulling into helix shape

tertiary-
disulphide bonds/bridges
-> ionic bonds
-> hydrogen bonds (v weak)
-> hydrophobic & hydrophillic interactions
-> covalent bonds

quaternary: all of above

29
Q

outline the fluctuations in a predator- prey relationship.

A
  1. increase in prey population provides more food for the predators, which allows more predators to survive and reproduce
  2. increase in predator population increases intraspecific competition for food, but the the prey population declines drastically and can no longer support the large prey population
  3. predator population declines as a result of not enough food
  4. reduced predator numbers means less of prey population being killed- more prey organisms survive and reproduce

cycle repeats

A level biology (19 decks)

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