Brainscape's Knowledge GenomeTM

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


See full index

Biology > UNIT 3 > Flashcards

UNIT 3 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Surface area to volume ratio

A

•The surface area of an organism divided by its volume

•the larger the organism, the smaller the ratio

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

Factors
affecting gas
exchange

A

•diffusion distance

•surface area

•concentration gradient

•temperature

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

Ventilation

A

•Inhaling and exhaling in humans

• controlled by diaphragm and antagonistic interaction of internal and external intercostal muscles

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

Inspiration

A

• External intercostal muscles contract and internal relax

• pushing ribs up and out

• diaphragm contracts and flattens

• air pressure in lungs drops below atmospheric pressure as lung volume increases

• air moves in down pressure
gradient

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

Expiration

A

• External intercostal muscles relax and internal contract

• pulling ribs down and in

• diaphragm relaxes and domes

• air pressure in lungs increases above atmospheric pressure as lung volume decreases

• air forced out down pressure
gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Passage of gas
exchange

A

• Mouth / nose -> trachea -> bronchi -> bronchioles -> alveoli

• crosses alveolar epithelium into capillary endothelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Alveoli
structure

A

• Tiny air sacs

• highly abundant in each lung - 300 million

• surrounded by the capillary network

• epithelium 1 cell thick

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

Why large
organisms need
specialised
exchange surface

A

• They have a small surface area to volume ratio

• higher metabolic rate - demands efficient gas exchange

• specialised organs e.g. lungs / gills designed for exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Fish gill
anatomy

A

• Fish gills are stacks of gill filaments

• each filament is covered with gill lamellae at right angles

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

How fish gas
exchange surface
provides large
surface area

A

• Many gill filaments covered in many gill lamellae are positioned at right angles

• creates a large surface area for efficient diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Countercurrent
flow

A

• When water flows over gills in opposite direction to flow of blood in capillaries

• equilibrium not reached

• diffusion gradient maintained across entire length of gill lamellae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Name three
structures in
tracheal system

A

• Involves trachea, tracheoles, spiracles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How tracheal
system provides
large surface area

A

• Highly branched tracheoles

• large number of tracheoles

• filled in ends of tracheoles moves into tissues during exercise
• so larger surface area for gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Fluid-filled
tracheole ends

A

• Adaptation to increase movement of gases

• when insect flies and muscles respire anaerobically- lactate produced

• water potential of cells lowered, so water moves from tracholes to cells by osmosis

• gases diffuse faster in air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do insects
limit water loss

A

• Small surface area to volume ratio

• waterproof exoskeleton

• spiracles can open and close to reduce water loss

• thick waxy cuticle - increases diffusion distance so less evaporation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Dicotyledonous
plants leaf
tissues

A

• Key structures involved are mesophyll layers

• (palisade and spongy mesophyll)

• stomata created by guard cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Gas exchange
in plants

A

• Palisade mesophyll is site of photosynthesis

• oxygen produced and carbon dioxide used creates a concentration gradient

• oxygen diffuses through air space in spongy mesophyll and diffuse out stomata

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Role of guard
cells

A

• swell - open stomata

• shrink - closed stomata

• at night they shrink, reducing water loss by evaporation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Xerophytic
plants

A

• Plants adapted to survive in dry environments with limited water (e.g. marram grass/cacti)

• structural features for efficient gas exchange but limiting water loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Adaptations of
xerophyte

A

• Adaptations to trap moisture to increase humidity -> lowers water potential inside plant so less water lost via osmosis
• sunken stomata
• curled leaves
• hairs

• thick cuticle reduces loss by evaporation

• longer root network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Digestion

A

• Process where large insoluble biological molecules are hydrolysed into smaller soluble molecules

• so they can be absorbed across cell membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Locations of
carbohydrate
digestion

A

• Mouth -> duodenum -> ileum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Locations of
protein
digestion

A

• Stomach -> duodenum -> ileum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Endopeptidases

A

• Break peptide bonds between amino acids in the middle of the chain

• creates more ends for exopeptidases for efficient hydrolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Exopeptidases

A

• Break peptide bonds between amino acids at the ends of polymer chain

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

Membrane-
bound
dipeptidases

A

• Break peptide bond between two amino acids

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

Digestion of
lipids

A

• Digestion by lipase (chemical)

• emulsified by bile salts (physical)

• lipase produced in pancreas

• bile salts produced in liver and stored in gall bladder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Lipase

A

• Produced in pancreas

• Breaks ester bonds in triglycerides to form :
• monoglycerides
• glycerol
• fatty acids

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

Role of bile
salts

A

• Emulsify lipids to form tiny droplets and micelles

• increases surface area for lipase action - faster hydrolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Micelles

A

• Water soluble vesicles formed from fatty acids, glycerol, monoglycerides and bile salts

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

Lipid
absorption

A

• Micelles deliver fatty acids, glycerol and monoglycerides to epithelial cells of ileum for absorption

• cross via simple diffusion as lipid-soluble and non-polar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Lipid
modification

A

• Smooth ER reforms monoglycerides / fatty acids into tryglycerides

• golgi apparatus combines tryglycerides with proteins to form vesicles called chylomicrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How lipids enter
blood after
modification

A

• Chylomicrons move out of cell via exocytosis and enter lacteal

• lymphatic vessels carry chylomicrons and deposit them in bloodstream

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Haemoglobin
(Hb)

A

• Quaternary structure protein
• 2 alpha chains
• 2 beta chains
• 4 associated haem groups in each chain.
containing Fe2+

• transports oxygen

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

Affinity of
haemoglobin

A

• The ability of haemoglobin to attract / bind to oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Saturation of
haemoglobin

A

• When haemoglobin is holding the maximum amount of oxygen it can hold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Loading /
unloading of
haemoglobin

A

• Binding/detachment of oxygen to haemoglobin

• also known as association and disassociation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Oxyhaemoglobin
dissociation
curve

A

• oxygen is loaded in regions with high partial pressures (alveoli)

• unloaded in regions of low partial pressure (respiring tissue)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Oxyhaemoglobin
dissociation curve
shifting left

A

• Hb would have a higher affinity for oxygen

• load more at the same partial pressure

• becomes more saturated

• adaptation in low-oxygen environments

• e.g. llamas/ in foetuses

•

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Cooperative
binding

A

• Hb’s affinity for oxygen increases as more oxygen molecules are associated with it

• when one binds, Hb changes shape meaning others bind more easily

• explaining S shape of curve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

How carbon
dioxide affects
haemoglobin

A

• When carbon dioxide dissolves in liquid, carbonic acid forms

• decreases pH causing Hb to change shape

• affinity decreases at respiring tissues

• more oxygen is unloaded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Bohr effect

A

• High carbon dioxide partial pressure

• causes oxyhaemoglobin curve to shift to the right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Oxyhaemoglobin
dissociation curve
shifting right

A

• Hb has lower affinity for oxygen

• unloads more at the same partial pressures

• less saturated

• present in animals with faster metabolisms that need more oxygen for respiration

• e.g. birds/rodents

•

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Closed
circulatory
system

A

• Blood remains within blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Name different
types of blood
vessels

A

• Arteries, arterioles, capillaries, venules and veins

46
Q

Structure of
arteries

A

• Thick muscular layer

• thick elastic layer

• thick outer layer

• small lumen

• no valves

47
Q

Capillary
endothelium

A

• Extremely thin

• one cell thick

• contains small gaps for small molecules to pass through (e.g. glucose, oxygen)

48
Q

Capillaries

A

• Form capillary beds

• narrow diameter (1 cell thick) to slow blood flow

• red blood cells squashed against walls shortens diffusion pathway

• small gaps for liquid / small molecules to be forced out

49
Q

Arterioles

A

• Branch off arteries

• thickest muscle layer to restrict blood flow

• thinner elastic layer and outer layer than arteries as pressure lower

50
Q

Tissue fluid

A

• Liquid bathing all cells

• contains water, glucose, amino acids, fatty acids, ions and oxygen

• enables delivery of useful molecules to cells and removal of waste

51
Q

Tissue fluid
formation

A

• At arteriole end, the smaller diameter results in high hydrostatic pressure

• small molecules forced out (ultrafiltration)

• red blood cells / large proteins too big to fit through capillary gaps so remain

52
Q

Reabsorption
of tissue fluid

A

• Large molecules remaining in capillary lower its water potential

• towards venule end there is lower hydrostatic pressure due to loss of liquid

• water reabsorbed back into capillaries by osmosis

53
Q

Role of the lymph
in tissue fluid
reabsorption

A

• Not all liquid will be reabsorbed by osmosis as equilibrium will be reached

• excess tissue fluid (lymph) is absorbed into lymphatic system and drains back into bloodstream and deposited near heart

54
Q

Cardiac
muscle

A

• Walls of heart having thick muscular layer

• unique because it is:
• myogenic - can contract and relax without
nervous or hormonal stimulation
• never fatigues so long as adequate oxygen
supply

55
Q

Coronary
arteries

A

• Blood vessels supplying cardiac muscle with oxygenated blood

• branch off from aorta

• if blocked, cardiac muscle will not be able to respire, leading to myocardial infarction (heart attack)

56
Q

Structure of heart

A

LEFT:

57
Q

Adaptation of
left ventricle

A

• Has a thick muscular wall in comparison to right ventricle

• enables larger contractions of muscle to create higher pressure

• ensures blood reaches all body cells

58
Q

Veins
connect to
the heart

A

• Vena cava - carries deoxygenated blood from body to right atrium

• Pulmonary vein - carries oxygenated blood from lungs to left atrium

59
Q

Arteries
connected to
the heart

A

• Pulmonary artery - carries deoxygenated blood from right ventricle to lungs

• Aorta - carries oxygenated blood from left ventricle to rest of the body

60
Q

Valves within
the heart

A

• Ensure unidirectional blood flow

• semilunar valves are located in aorta and pulmonary artery near the ventricles

• atrioventricular valves between atria and ventricles

61
Q

Opening and
closing of valves

A

• Valves open if the pressure is higher behind them compared to in front of them.

• AV valves open when pressure in atria > pressure in ventricles

• SL valves open when pressure in ventricles > pressure in arteries

62
Q

The Septum

A

• Muscle that runs down the middle of the heart

• separates oxygenated and deoxygenated blood

• maintains high concentration of oxygen in oxygenated blood

• maintaining concentration gradient to enable diffusion to respiring cells

63
Q

Cardiac output

A

• Volume of blood which leaves one ventricle in one minute.

• Cardiac output = heart rate x stroke volume

• heart rate = beats per minute

64
Q

Stroke volume

A

• Volume of blood that leaves the heart each beat

• measured in dm^3

65
Q

Cardiac cycle

A

• Consists of diastole, atrial systole and ventricular systole

66
Q

Diastole

A

• Atria and ventricular muscles are relaxed

• when blood enters atria via vena cava and pulmonary vein

• increasing pressure in atria

67
Q

Atrial systole

A

• Atria muscular walls contract, increasing pressure further.

• pressure atria > pressure ventricles

• atrioventricular valves open and blood flows into ventricles

• ventricular muscle relaxed

68
Q

Ventricular
systole

A

• After a short delay (so ventricles fill), ventricular muscular walls contract

• pressure ventricle > atria pressure and artery pressure

• atrioventricular valves close and semi-lunar valves open

• blood pushed into artery

69
Q

Transpiration

A

• Loss of water vapour from stomata by evaporation

• affected by:
• light intensity
• temperature
• humidity
• wind

• can be measured in a lab using
a potometer

70
Q

How light
intensity affects
transpiration

A

• As light intensity increases, rate of transpiration increases

• more light means more stomata open

• larger surface area for evaporation

71
Q

How temperature
affects
transpiration

A

• As temperature increases, rate of transpiration increases

• the more heat there is, the more kinetic energy molecules have

• faster moving molecules increases evaporation

72
Q

How humidity
affects
transpiration

A

• As humidity increases, transpiration decreases

• the more water vapour in the air, the greater the water potential outside the leaf

• reduces water potential gradient and evaporation

73
Q

How wind
affects
transpiration

A

• As wind increases, rate of transpiration increases

• the more air movement, the more humid areas are blown away

• maintains water potential gradient, increasing evaporation

74
Q

Cohesion in
plant transport

A

• Because of the dipolar nature of water, hydrogen bonds can form - cohesion

• water can travel up xylem as a continuous column

75
Q

Adhesion in
plant transport

A

• Water can stick to other molecules (xylem walls) by forming H-bonds

• helps hold water column up against gravity

76
Q

Root pressure in
plant transport

A

• As water moves into roots by osmosis, the volume of liquid inside the root increases

• therefore the pressure inside the root increases

• this forces water upwards

77
Q

Cohesion-
tension theory

A

• As water evaporates out the stomata, this lowers pressure

• water is pulled up xylem (due to negative pressure)

• cohesive water molecules creates a column of water

• water molecules adhere to walls of xylem pulling it upwards

• this column creates tension, pulling xylem inwards

78
Q

Translocation

A

• Occurs in phloem

• explained by mass flow hypothesis

• transport of organic substances through plant

79
Q

Sieve tube
elements

A

• Living cells

• contain no nucleus

• few organelles

• this makes cell hollow

• allowing reduced resistance to flow of sugars

80
Q

Companion
cell

A

• Provide ATP required for active transport of organic substances

• contains many mitochondria

81
Q

Mass flow
hypothesis

A

• Organic substances, sucrose, move in solution from leaves (after photosynthesis) to respiring cells

• source -> sink direction

82
Q

How is pressure
generated for
translocation

A

• Photosynthesising cells produce glucose which diffuses into companion cell

• companion cell actively transports glucose into phloem

• this lowers water potential of phloem so water moves in from xylem via osmosis

• hydrostatic pressure gradient generated

83
Q

What happens to
sucrose after
translocation?

A

• Used in respiration at the sink

• stored as insoluble starch

84
Q

Tracing

A

• Involves radioactively labelling carbon - used in photosynthesis

• create sugars with this carbon

• thin slices from stems are cut and placed on X-ray film which turns black when exposed to radioactive material

• stems will turn black as that is where phloem are

85
Q

Ringing
experiments

A

• Ring of bark (and phloem) is peeled and removed off a trunk

• consequently, the trunk swells above the removed section

• analysis will show it contains sugar

• when phloem removed, sugar cannot be transported

86
Q

How do small
organisms
exchange gases

A

• Simple diffusion

• across their surface

87
Q

Why don’t small
organisms need
breathing systems

A

• They have a large surface area to volume ratio

• no cells far from the surface

88
Q

How alveoli
structure relates
to its function

A

• Round shape & large number in - large surface area for gas exchange (diffusion)

• epithelial cells are flat and very thin to minimise diffusion distance

• capillary network maintains concentration gradient

89
Q

How fish gas
exchange surface
provides a short
diffusion distance

A

• Thin lamellae epithelium means short distance between water and blood

• capillary network in every lamella

90
Q

How fish gas
exchange surface
maintains diffusion
gradient

A

• Counter-current flow mechanism

• circulation replaces blood saturated with oxygen

• Ventilation replaces water with oxygen removed

91
Q

Name of gas
exchange system in
terrestrial insects

A

• Tracheal system

92
Q

Describe
structure of
spiracles

A

• Round, valve-like openings

• running along the length of the abdomen

93
Q

Describe trachea
& tracheoles
structure

A

• Network of internal tubes

• have rings of cartilage adding strength and keeping them open

• trachea branch into smaller tubes - tracheoles

• tracheoles extend through all tissues delivering oxygen

94
Q

How tracheal
system provides
short diffusion
distance

A

• Tracheoles have thin walls so short diffusion distance to cells

95
Q

How tracheal
system maintains
concentration
gradient

A

• Body can be moved by muscles to move air - ventilation

• Use of oxygen in respiration and production of CO2 sets up steep concentration gradients

96
Q

Amylase

A

• Produced in pancreas & salivary gland

• hydrolyses starch into maltose

97
Q

Membrane-bound
disaccharidases

A

• Maltase / sucrase / lactase

• hydrolyse disaccharides into monosaccharides

98
Q

Enzymes
involved in
protein digestion

A

• endopeptidases

• exopeptidases

• membrane-bound dipeptidases

99
Q

Products of
protein
digestion

A

• Large polymer proteins are hydrolysed to amino acids

100
Q

Double
circulatory
system

A

• Blood passes through heart twice

• pulmonary circuit delivers blood to/from lungs

• systemic circuit delivers blood to the rest of the body

101
Q

Coronary
arteries

A

• Supply cardiac muscle with oxygenated blood

• for continued respiration and energy production for contraction

102
Q

Blood vessels
entering / exiting
the kidney

A

• Renal artery carries oxygenated blood to kidney

• renal vein carries deoxygenated blood to heart

103
Q

Blood vessels
entering /
exiting the lung

A

• Pulmonary artery carries deoxygenated blood to lung

• pulmonary vein carries oxygenated blood to heart

104
Q

Blood vessels
entering /
exiting the heart

A

• Vena cava carries deoxygenated blood to heart (right atrium)

• aorta carries oxygenated blood to body

• pulmonary artery - carries blood from the heart to the lungs

• pulmonary vein - carries blood from the lungs into the heart

105
Q

Describe then
structure of
veins

A

• Thin muscular layer

• thin elastic layer

• thin walls

• valves

106
Q

Explain role of
elastic layer in
arteries

A

• Thick elastic layer

• to help maintain blood pressure

• by stretching and recoiling

107
Q

Describe the
elastic layer in
veins

A

• Thin elastic layer as pressure lower

• cannot control the flow of blood

108
Q

Explain the role
of valves in veins

A

• Due to low pressure in veins

• skeletal muscle usually used to flatten walls of veins for blood flow

• valves prevent the backflow of blood

• unidirectional flow

109
Q

What causes the
AV valves to open

A

• Higher pressure in the atria than in the ventricles

110
Q

What causes the
semi-lunar
valves to open

A

• Higher pressure in the ventricles than in the arteries

111
Q

How are glucose
and amino acids
absorbed

A

• Via co-transport in the ileum

112
Q

Investigating
translocation

A

• Can be investigated using tracer and ringing experiments

• proves phloem transports sugars not xylem

Biology (3 decks)

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