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Maintaining a balance Flashcards

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Biology 101 flashcards
1
Q

Most organisms are active in a limited temperature range

A
  • Ensures metabolism (sum of all chemical processes in a organism)
  • By providing constant temp, chemical balance
  • Effect→ Maintains optimum conditions for enzyme functioning
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2
Q

What are enzymes?

A
  • Globular proteins
  • Increase rate of reactions (catalyse)
  • Unchanged at end of reaction
  • Bind to substrate → active site
  • Active site→ pocket (protein folds where substrates bind)
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3
Q

Chemical composition of enzymes

A
  • Protein molecules (amino acid chain)
  • Folded in a specific shape
  • Enzymes acts on reactant molecule (substrate)
  • Enzymes fit with substrate as specific location on surface of enzyme molecule (ACTIVE SITE)
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4
Q

Role of enzymes in metabolism; Acceleration of chemical reactions

A
  • Catalysts→ speeds or slows reactions without temp change
  • Heat damages tissues in cells
  • Lower activation energy so reaction can occur quickly
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5
Q

Role of enzymes in metabolism; Lowering of activation energy

A
  • Don’t produce activation energy; reduces amount needed

- Brings specific molecules together, instead of relying on random collision

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6
Q

Role of enzymes in metabolism; Action on specific substrates

A
  • Only one particular enzyme can work on only one particular substrate molecules
  • Active site is reciprocally shaped to bind with that molecule
  • Not chemically changes in reaction→ can be reused
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7
Q

Enzyme characteristics; Temperature sensitive

A
  • In cells function best at body temp
  • Above 60℃→ stop working
  • Heat causes hydrogen bonds to break → alters shape/structure
  • Change affects active site→ not reciprocally shaped
  • Temp too high/low → will denature
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8
Q

Enzyme characteristics; pH sensitive

A
  • Own narrow pH range functions efficiently
  • Levels outside optimum→ alters shape/stops functioning
  • Most function at or near neutral
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9
Q

Enzyme characteristics; substrate specific

A
  • Molecules specific→ act on only one type of substrate
  • Each enzyme catalyses on particular reaction
  • E.g. Rennin acts on protein in milk causing it to curdle
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10
Q

Induced fit model

A
  • Enzyme molecule changes shape as substrate molecule approaches (molecules are flexible)
  • Reaction occurs→ substrate is changed, product is released (enzyme returns to original form)
  • E.g. gloved hand changes to catch ball; active site is palm, closes around ball when ball draws near
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11
Q

Lock and key model

A
  • Simply fits into active site to form immediate reaction (not considered great explanation)
  • Brings active site of both molecules into alignment; reaction occurs quickly
  • Depends on unlikely event of random collisions between enzyme and substrate
  • E.g. Like trying to get key in lock by throwing key at lock with eyes closed
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12
Q

First hand investigation; increased temperature (enzyme)

A
  • Milk with rennin; curdled quickly (temp approx 37 0C)
  • Temps higher or lower→ milk with rennin doesn’t curdle
  • Temp higher or lower than optimum 37 0C→ rennin doesn’t react and curdle milk
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13
Q

First hand investigation; change in pH (enzyme)

A
  • pH affects activity of catalase in potato tissue (has optimum pH)
  • Height of foam measured when catalase put in hydrogen peroxide
  • pH of 9 is optimum for catalase (average bubble height was higher)
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14
Q

Identify the pH as a way of describing the acidity of a substance

A
  • pH scale→ indicates acidity

- Lower value= acidic, Higher value = alkaline

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15
Q

Explain why the maintenance of a constant internal environment is important for optimal metabolic efficiency

A
  • Must be stable → so enzymes can function, metabolism efficiency maintained
  • Enzymes are sensitive to changes, only work in narrow range of pH and temp.
  • Small variations from narrow range→ small decreases in activity
  • Larger variation from narrow range → reduced metabolic efficiency
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16
Q

Stimuli (negative feedback model)

A

Increased or decreased body temp (E.g. Hot or cold surroundings, exercise)

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17
Q

Co-ordinating (control) centre (negative feedback model)

A

Hypothalamus detects change and activates cooling or warming mechanisms

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18
Q

Effectors (negative feedback model)

A

High temp:

  • Skin vessels dilate (blood carries heat to skin surface)
  • Sweat glands (Increase evaporative cooling)

Low temp:

  • Skin vessels constrict (reduces heat loss from skin surface)
  • Skeletal muscles activates (shivering generates heat)
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19
Q

Negative feedback loop (negative feedback model)

A

Body temp decreases or increases, hypothalamus shuts off warming/cooling mechanism

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20
Q

Describe homoeostasis, as the process by which organisms maintain a relatively stable internal environment

A
  • Maintenance of constant or almost constant internal state, regardless of external environmental change
  • Body regulates respiratory games, protect against pathogens, maintain salt and fluid balance, constant body temp, energy and nutrient supply
  • Kept at constant level regardless of environmental change: body temp, blood pH, water/salt balance, blood pressure, oxygen and carbon dioxide concentration.
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21
Q

Explain that homeostasis consists of 2 stages:

- Detecting changes from the stable state - Counteracting changes from the stable state

A
  • Any internal environment deviation must be quickly corrected. Counteract; use corrective mechanism

Stage 1: Detect change from stable state: Receptors detect change. E.g. Thermoreceptors in skin

Stage 2: Counteract change: Effector (muscle or gland) receives message to counteract change. Response is initiated to reverse change and restore body to stable.

  • E.g. Muscles shiver to generate heat
  • If variation exceeds normal range; NEGATIVE FEEDBACK counteracts change, returns body to homeostasis
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22
Q

Analyse information from secondary sources to describe adaptations and responses that have occurred in Australian organisms to assist temperature regulation
GENERATE/RETAIN HEAT

A

Generate heat:

  • Shivering: Rapid muscle contractions
  • Increased metabolism; Activity of thyroid gland stimulated, speeds up metabolism

Retain heat:

  • Raised hair: raps warm air, reduces heat loss by convection. Muscles contract
  • Vasoconstriction: Blood vessels construct so heat carried in blood is redirected to core of body, prevents heat loss from body surface
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23
Q

Analyse information from secondary sources to describe adaptations and responses that have occurred in Australian organisms to assist temperature regulation
RELEASE HEAT/GENERATE LESS HEAT

A

Release heat:

  • Vasodilation: Arterioles expand, blood directed to body surface, heat lost by radiation, convection
  • Sweating: liquid secreted onto skin, heat removed to evaporate liquid

Generate less heat:

  • Decreased metabolism: Thyroid gland lowers metabolism, generates less heat
  • Flattened hairs: Laid flat, increases heat loss
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24
Q

Outline the role of the nervous system in detecting and responding to environmental changes

A
  • Function of nervous system→ coordination
  • Receptors; Thermoreceptors, hypothalamus detects change → converts to message, travels along nerves in CNS (brain, spinal cord)
  • Control centre: CNS processes info about change in specific parts of brain
  • Motor nerves; Carry info as nerve impulses from CNS to effectors
  • Effectors: Muscle or gland receives impulses, instruct effectors to respond
  • Response; Counteracts original change; ensures homeostasis
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25
Q

Identify the broad range of temperatures over which life is found compared with the narrow limits for individual species

A
  • Living creatures can survive temps of -70℃ (poles), high as 56℃ (deserts), 350℃ ( hot vents in sea)
  • Individual species need much narrower range of temp (have optimum temp they function at)
  • Tolerance range; temp range species can survive, usually few degrees outside of optimum
  • Vast range of temps→ beneficial for species diversity
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26
Q

Endothermic

A

Maintain constant internal temp; using internal metabolism to generate heat (mammals)

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27
Q

Ectothermic

A

Body temp governed by external heat sources, environment regulates temp (reptiles)

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28
Q

Compare responses of named Australian ectothermic and endothermic organisms to changes in the ambient temperature and explain how these responses assist temperature regulation :ECTOTHERMIC

A

Blue Tongue Lizard:

  • Cold weather→ remain inactive (buried in shelter) lowers metabolic rate→ conserve energy
  • Sunny days→ emerge to bask→ raises temp
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29
Q

Compare responses of named Australian ectothermic and endothermic organisms to changes in the ambient temperature and explain how these responses assist temperature regulation: ENDOTHERMIC

A

Red Kangaroo:

  • Hottest part of day→ seek shade, tail and hind legs shaded by rest of body (reduces surface are exposed to sun)
  • Lowers body temp
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30
Q

Identify some responses of plants to temperature change

A

Leaf Fall; Hot conditions→ plants drop leaves (reduces surface area to sun, reduces water loss through transpiration)

Shiny Leaves: Reflect solar radiation→ reduces heat absorbed

Orientation: Vertical orientation→ reduces surface area to sun, reduces amount of heat exposed to)

Ice formation between cells:Temps below freezing→ ice form in cells, forms in gaps between plant cells; cell walls protects cytoplasm being pierced by ice crystal→ cell survives

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31
Q

PLANTS AND ANIMALS TRANSPORT DISSOLVED NUTRIENTS AND GASES IN A FLUID MEDIUM

A
  • Transport system; distributes food/oxygen to cells, removes carbon dioxide and waste
  • Blood; fluid transport medium; contains 3 types of cells
  • RBC: Carry oxygen, maintain pH of blood
  • WBC: Part of immune system, protects against invading organism
  • Platelets: Clotting of blood, stops blood loss
  • Plasma; Makes up most blood volume; carries nutrients, gases etc
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32
Q

Identify the form(s) in which each of the following is carried in mammalian blood:
- Carbon dioxide

A
  • Cellular respiration product carried to lungs
  • 70% as hydrogen carbonate ions, 7% as plasma, 23% combined with haemoglobin
  • Travels in RBC, plasma
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33
Q

Identify the form(s) in which each of the following is carried in mammalian blood:
- Oxygen

A
  • Carried from lungs to heart, body tissues

- 98.5% as heamoglobin in RBC, 1.5% dissolved in plasma

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34
Q

Identify the form(s) in which each of the following is carried in mammalian blood:
- Water

A
  • Reabsorbed from nephron to body cells

- Travels in plasma as water molecules

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35
Q

Identify the form(s) in which each of the following is carried in mammalian blood:
- Salts

A
  • Reabsorbed from nephrons to all body cells.

- Dissolved in plasma as ions

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36
Q

Identify the form(s) in which each of the following is carried in mammalian blood:
- Lipids

A
  • Absorbed across villi wall of small intestine to veins in shoulder,
  • As fatty acids, glycerol dissolved in plasma
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37
Q

Identify the form(s) in which each of the following is carried in mammalian blood:
- Nitrogenous wastes

A
  • Urea processed in liver → moves into blood

- Transported dissolved in plasma to kidneys (removed across nephrons)

38
Q

Identify the form(s) in which each of the following is carried in mammalian blood:
- Other products of digestion (amino acids, glucose)

A
  • Proteins broken down into amino acids, transported across small intestine wall.
  • Dissolved in plasma to be absorbed into cells for making proteins
39
Q

Perform a first- hand investigation to demonstrate the effect of dissolved carbon dioxide on the pH of water

A
  • Water in beaker (add universal indicator)
  • Blow bubbles with straw (carbon dioxide) for 2 mins
  • Colour will change→ estimate pH using colour chart (makes more acidic)
40
Q

Perform a first hand investigation using the light microscope and prepared slides to gather information to estimate the size of red and white blood cells and draw scaled diagrams of each

A
  • Known diameter of RBC= 7.5um
  • Calculate field of view (mini grid) → on slide estimate number of RBC that fit across diameter of fov
  • Estimate number of WBC, repeat and compare with known
41
Q

What is haemoglobin?

A
  • Haemoglobin: Oxygen carrying molecule (carries 4 oxygen molecules)
  • Each RBC carried 200-300 million haemoglobin molecules→ so 800-1200 million oxygen molecules
  • Protein of 4 polypeptide chains (globins) bonded to iron containing group (haem)
42
Q

Adaptive advantage of Haemoglobin; Increases oxygen-carrying capacity of blood

A
  • 1 haemoglobin molecule binds with 4 oxygen molecules

- More oxygen can be carried in blood cells

43
Q

Adaptive advantage of Haemoglobin: Increases binding of oxygen once first oxygen molecule binds

A
  • Bonding causes haemoglobin to change slightly, easier for subsequent oxygen molecules to bind
  • Increases rate and efficiency of oxygen intake
44
Q

Adaptive advantage of Haemoglobin: Release of oxygen increases when carbon dioxide is present

A
  • Has to release oxygen from blood to where it’s needed
  • Metabolising cells release carbon dioxide (lowers pH)
  • Haemoglobin at lower pH has lowered attraction to oxygen (can release)
45
Q

Adaptive advantage of Haemoglobin: Enclosed in RBC

A

If it were just dissolved in plasma, oxygen would upset osmotic plasma balance

46
Q

Arteries

A
  • Carry blood from heart to other body parts
  • Thick walls (withstand high pressure of pumped blood)
  • No valves→ pressure is high (not needed to stop backflow)
  • Elastic wall fibres→ increases elasticity, expand for increased blood volume pumped in each heartbeat
47
Q

Veins

A
  • Carry blood from tissues back to heart
  • Thinner walls→ blood flows in, not pumped
  • Wider lumen (easy blood flow)
  • Valves (small pocket folds→ lines lumen) → prevents backflow
48
Q

Capillaries

A
  • Brings blood into contact with tissue (chemical exchange in cells and bloodstream)
  • Large network to spread blood (no cell far away from blood supply)
  • Walls only 1 cell layer thick (efficient diffusion)
  • Small lumen→ Forces RBC to pass in single file (slows flow, increases exposed surface area for gaseous exchange)
49
Q

Analyse information from secondary sources to identify current technologies that allow measurement of oxygen saturation and carbon dioxide concentrations in blood and describe and explain the conditions under which see technologies are used.

A
  • Levels of chemical in blood→ indicate state of health
  • Changes in level→ ineffective metabolic functioning (results in poor health)
  • Carbon dioxide/oxygen concentrations in blood→ how well lungs function, blood circulates
    PULSE OXIMETER:
  • Clip with sensor placed on finger→ shows pulse rate and oxygen saturation level
  • Check blood oxygen levels; people with heart attacks, cancer etc (non-invasive)

ARTERIAL BLOOD GAS ANALYSIS (ABG)

  • Invasive→ blood removed from artery, blood analysed in sample
  • Used to discover is patient has lung/kidney disorder, lung disease
  • Details about level of chemicals in blood (pH, bicarbonate ions, oxygen levels
50
Q

Chemical composition of blood

A
  • Circulatory system; transport of substances to and away from parts (gases, nutrients, wastes, hormones)
  • Metabolism→ relies in correct chemical balance brought to cells, removal of wastes
  • Function of organ→ determines difference in chemical concentration of blood entering or leaving
  • All organs→ Internal gas exchange (cellular respiration) lungs→ external
  • Deoxygenated blood→ arrives at lungs, releases CO2 and picks up oxygen→ Haemoglobin carries
  • CO2→ cells release,diffuses into capillaries→ carried in haemoglobin→ travels back via veins
51
Q

Changes in chemical composition of blood passing through

- Lungs

A

Increase Oxygen

Decrease CO2

52
Q

Changes in chemical composition of blood passing through

- Any organ not lungs

A

Decrease Oxygen

Increase CO2

53
Q

Changes in chemical composition of blood passing through

- Any organ involving absorbing digested food

A

Increase in digestive end products (glucose)

54
Q

Changes in chemical composition of blood passing through

- Liver

A
  • Decrease in digestive end products (E.g. Glucose, fatty acids, amino acids)
  • Increase nitrogenous wastes (Urea)
55
Q

Changes in chemical composition of blood passing through

- Kidney

A

Decrease nitrogenous wastes (filter and excrete)

56
Q

Changes in chemical composition of blood passing through

- Glands

A

Increase in hormones (secreted and travel to where needed)

57
Q

Outline the need for oxygen in living cells and explain why removal of carbon dioxide from cells is essential

A
  • Oxygen→ necessary for cellular respiration (combines with glucose during CR to release energy ATP)
  • CO2→ Must be removed to prevent pH changes in cells and bloodstream
  • CO2 reacts with water (in cytoplasm or plasma) → forms carbonic acid (build up is toxic) lowers pH
  • Lowered pH→ prevents enzyme functioning (reduces metabolic efficiency)
58
Q

Analyse information from secondary sources to identify the products extracted from donated blood and discuss the uses of these products

A
  • First transfusions (most killed) 120 years ago → discover specific blood types (incompatible groups= fatal)
  • Before blood donations→ cross matching of blood groups needed
  • RBC→ helps patients carry more oxygen (helps replace lost cells after bleeding)
  • Platelet→ treats bleeding from diseases where platelets don’t function properly
  • Frozen plasma→ patients who need immediate clotting (E.g. After large transfusions

LIABLE PRODUCTS:

  • Perishable→ short shelf life
  • Need to be transported in refrigerated conditions
  • E.g. RBC, platelets, plasma

STABLE PRODUCTS:

  • Longer shelf life
  • Produced by- separating different protein components from plasma
  • E.g. Blood clotting factors, immunoglobulins
59
Q

Describe current theories about processes responsible for the movement of materials through plants in xylem and phloem; XYLEM

A
  • Carries water ions from roots to leaves
  • Made of vessels, tracheids, fibres, parenchyma cells

Transpiration stream theory

  • Water sucked up stem; evaporative pull of transpiration
  • Water drawn up tubes; replace water loss from evaporation in leaves

Evidence:

  • Vessels are hollow→ offer little resistance to water
  • Concentration gradient; leaf surface (high), centre of leaf (low) creates tension as moves across gradient→ doesn’t break due to cohesion/adhesion of molecules
60
Q

Describe current theories about processes responsible for the movement of materials through plants in xylem and phloem; PHLOEM

A
  • Carries nutrients (sugars, amino acids) to all parts of plant, moves both ways
  • Made of fibres, parenchyma, sieve cells and companion cells

Pressure flow theory

  • Active process (needs energy) driven by osmotic pressure gradients (generated by differences in sugar water concentration)
  • Sugar loaded into phloem at source then uploads into surrounding tissue (sink)
  • Loading attracts water flow (osmotic pressure)
  • Offloading at sink→ water moves out
61
Q

Analyse and present information from secondary sources to report on progress in the production of artificial blood and use available evidence to propose reasons why such research is needed

A
  • Past→ attempts to treat bleeding in WW1 & WW2→ failed. Encouraged modern artificial blood
  • Blood transfusions work (Problems; need cross matching and short storage life)
  • 1980’s→ urgent research; response to sudden appearence of HIV in blood transfusion patients
  • AIDS crisis in South Africa- driving force in becoming one of the first countries to clear artificial blood for limited use in patients
62
Q

Ideal characteristics of artificial blood

A
  • Can be stored for long periods of time and easily transported
  • Doesn’t need to be cross matched for different blood types
  • Continues to circulate (doesn’t settle) and has no toxic effects on body
  • When patient’s own blood is restored→ can be safely excreted
63
Q

Explain why the concentration of water in cells should be maintained within a narrow range for optimal function

A

Changes in water concentration lead to corresponding changes in solute concentration in cells

  • Water in cells→ determines osmotic pressure of cells
  • Water moves by osmosis→ water movement into/ out of cells depends on solute concentration inside/ out of cells

Water provides necessary medium in which all chemical reactions of metabolism occur:

  • Chemical reactions occur→ only if reactants are dissolved in water; levels must be constant
  • Water concentration; Too much→ cells may burst. Too little→ cell contents shrink
  • Too little water→ increase in solute concentration→ lowers pH (must be maintained→ enzymes)
  • Water accumulates→ may dilute reactants and slow down metabolism
64
Q

Explain why the removal of wastes is essential for continued metabolic activity

A
  • Accumulation of wastes is toxic→ must be removed to maintain homeostasis
  • If build up→ alters conditions→ stops enzyme functioning. Can change pH→ stops enzymes
  • Accumulation that doesn’t alter pH→ alters reaction rates, osmotic imbalance→ affects membrane functioning
  • E.g. Accumulation of Carbon Dioxide→ internal environment becomes too acidic
65
Q

Kidney vs renal dialysis: KIDNEY

A
  • Filters blood, remove waste/excess fluids→ turn into urine (excreted)
  • Passive: Glomerular capillaries diffuse wastes through membrane
  • Active: Reabsorption in nephrons, wastes reused into bloodstream
  • 180 L blood filters everyday (entire blood volume filtered 20-25 x per day)
  • Maintains chemical balance in blood
66
Q

Kidney vs renal dialysis: RENAL DIALYSIS

A
  • Carries out function of failed kidneys (cleans blood)
  • Haemodialysis→ transfers blood to machine to be filtered before returned to body
  • Glucose levels same in fluid (so doesnt diffuse)
  • Passive transport; diffusion of substances in dialysis membrane between blood and fluid
  • Blood filtered for 3-4 hours (2-3 times a week)
  • Removes wastes to stop accumulating; maintains chemical balance in blood
67
Q

Identify the role of the kidney in the excretory systems of fish and mammals

A

Water accumulates in body→ by eating/drinking, metabolism. Nitrogenous wastes→ metabolism
Water potential: Tendency of a solution to lose water by osmosis (typical; high water concentration)
Water concentration in environment; Determines organism’s need to conserve or lose water

68
Q

Identify the role of the kidney in the excretory systems of fish and mammals: FRESHWATER FISH

A
  • Live in rivers/lakes (high water potential) water freely available (few salts)
  • Urinate frequently; water accumulates (osmosis→ high concentration surroundings to low in fish)
  • Too much water in bodies→ Kidneys excrete excess and wastes. Conserve salt
69
Q

Identify the role of the kidney in the excretory systems of fish and mammals: MARINE FISH

A
  • Live in sea- urinate less (lose body water across gills to surroundings)
  • Salt diffuses into bodies→ main kidney function (remove excess)
  • Kidneys conserve water rather than extract
70
Q

Identify the role of the kidney in the excretory systems of fish and mammals: TERRESTRIAL MAMMALS

A
  • Water and salt loss from body;respiration ,excretion (sweat, urine)
  • Control mechanism; ensure balance maintained of amount excreted
  • Urine; dilute or concentrated (adjusted depending on body needs)
  • Large amount of salt lost by sweat→ needs replacing for stable osmotic pressure in body
71
Q

Explain why the process of diffusion and osmosis are inadequate in removing dissolved nitrogenous wastes in some organisms.

A
  • Both are slow (rely on concentration gradient difference; slows as difference is smaller, stops; equal)
  • Solution; combine active transport and osmosis (quick; removes waste even against gradient)
  • Used to pump salts from urine back into kidney (draws water with them by osmosis)
72
Q

Problems with diffusion

A

Rate of movement is slow
- Wastes must be dissolved with water when removed→ as concentrations equalise movement slows and stops

Not all wastes can be removed by diffusion
- If concentrations equalise and no further wastes removed→ pH would be altered

73
Q

Problems with osmosis

A

Too much water may be lost in urine
- Contains too much nitrogenous wastes, water will be drawn into urine to dilute waste (equalise concentration) → dilute urine (loses too much)

Movement of water may make wastes too dilute for excretion by diffusion
- Slows down excretion by diffusion (lowers concentration gradient)

74
Q

Present information to outline the general use of hormone replacement therapy in people who cannot secrete aldosterone

A
  • Adrenocortical insufficiency (Addison’s disease) some immune systems cause inflammation in own glands, other causes are tuberculosis and cancer
  • Decreased secretion of aldosterone→ increased sodium loss
  • Clinically; Person is weak, thin, have salt-cravings, faintness, feel light-headed, low blood-sugar
  • Most patients → require treatment with fludrocortisone plus cortisone as a replacement glucocorticoid
75
Q

Distinguish between active and passive transport and relate these to processes occurring in the mammalian kidney

A
  • Passive→ diffusion, osmosis (molecules move along concentration gradient) no energy input
  • Active→ needs cellular energy to move molecules against concentration gradient
  • Diffusion; Particles from region of high concentration to low until equilibrium is reached
  • Osmosis; water molecules from high water concentration to low,through semi permeable membrane
76
Q

Distinguish between active and passive transport and relate these to processes occurring in the mammalian kidney: PASSIVE IN KIDNEY

A
  • Limitations; relies on difference in concentration gradient (slow)
  • Tubules→ wastes from bloodstream to be excreted as urine
  • Substances needed→ removed from urine and returned to bloodstream
  • Passive moves water (osmosis), some wastes (ammonia, urea) into kidney
77
Q

Distinguish between active and passive transport and relate these to processes occurring in the mammalian kidney: ACTIVE IN KIDNEY

A
  • Sometimes have to move against gradient
  • Carrier proteins spans membrane and carrier molecule actively move chemicals from low to high concentration using cellular energy
  • Mainly sodium ions, glucose, amino acids across wall of nephron (reabsorbed)
  • Sodium pump in tubules→ transports salts from urine back into kidney (conserve salt and water→ salt draws water)
78
Q

Analyse information from secondary sources to compare and explain the differences in urine concentration of terrestrial mammals, marine fish and freshwater fish.

A 
Urine concentration; depends on need to conserve water
High in solutes=concentrated. Low in solutes= dilute
Fish; only 1 concentration; freshwater (large amounts of dilute) marine (small of concentrated)
TERRESTRIAL MAMMAL:
- Conserve water (concentrated)
- Consumes water (dilute)
Source; Drinking, eating 
MARINE FISH
- Only concentrated
- Sources; Drinks,osmosis out of fish
FRESHWATER FISH 
- Only dilute
- Sources; drinks, osmosis into fish
79
Q

Filtration in nephron

A
  • Filtration→ takes place surface between glomerulus, lining of Bowman’s capsule
  • High pressure; blood flowing through glomerulus (small substances squeeze through capillary wall under pressure, pass through cell layer in Bowman’s capsule→ move into lumen)
  • Blood cells, proteins retained in blood, large water volumes pass→ carry dissolved amino acids, glucose, wastes, salts (FLUID IS GLOMERULAR FILTRATE)
  • Substances body needs→ reabsorbed into bloodstream (so aren’t lost with urine) wastes excreted
80
Q

Reabsorption in nephron

A
  • Filtrate contains molecules needed (e.g. amino acids, glucose) actively reabsorbed in proximal tubule
  • Passed into interstitial fluid, capillaries surrounding nephron → form larger vessels to renal vein (carried back into general circulation)
  • 99% water reabsorbed by osmosis, only 1% excreted as urine
  • Ascending loop→ salts actively pumped into interstitial fluid in medulla (draw water out by osmosis)
81
Q

Secretion in nephron

A
  • Toxic substances removed from capillaries and tissues (wastes secreted into fluid with drugs)
  • Drugs secreted in proximal tubule, urea in descending loop of Henle
82
Q

Use available evidence to explain the relationship between the conservation of water and the production and excretion of concentrated nitrogenous wastes in a range of Australian insects and terrestrial mammals

A
  • Limited water availability→ must conserve water and excrete waste
  • High water availability→ water conservation not necessary (waste may be dilute)
  • Moth & Blowfly→ excrete uric acid as paste (low toxic) high energy needed , but conserves water
  • Spinifex hopping mouse→ concentrated urea; conserve water (moderate toxic)
  • Humans, moth, blowfly→ water not freely available (must be sourced)
  • Mouse→ arid climate, low water → sources from seeds, requires little drinking water
83
Q

Outline the role of the hormones, aldosterone and ADH (anti- diuretic hormone) in the regulation of water and salt levels in blood: (ADH)

A
  • When mammal dehydrates; blood volume drops→ detected by hypothalamus in brain
  • Stimulates pituitary gland to release ADH
    ADH acts on nephrons to increase reabsorption of water
  • Presence of ADH→ increases permeability of cell membranes lining distal tubule and collecting tubule
  • Water is reabsorbed from tubules into kidney tissue and bloodstream→ more water conserved
  • Regulation of blood volume: Maintain constant fluid volume; producing either large volume of dilute urine or a small concentration of concentrated urine (osmoregulaion; homeostasis)
84
Q

Outline the role of the hormones, aldosterone and ADH (anti- diuretic hormone) in the regulation of water and salt levels in blood: (ALDOSTERONE)

A

Secreted from cortex of adrenal gland (above the kidney)
When decreased concentration of sodium ions in the blood (decrease in blood volume/blood pressure)
When aldosterone via bloodstream reaches kidney→ increases permeability of the nephron to sodium (particularly in ascending loop of Henle)
Reabsorption of sodium ions from nephron into surrounding kidney tissue and capillaries occurs
Results in conservation of salt in body→ less is lost by urine
Regulation of solute concentration of blood; regulate amount of sodium, other ions reabsorbed or secreted in urine (osmoregulation; homeostasis)

85
Q

Process and analyse information from secondary sources and use available evidence to discuss processes used by different plants for salt regulation in saline environments.

A

MANGROVE:

  • Well adapted to changing salt levels in environment- salt avoidance and salt tolerance strategies
  • Can concentrate salt accumulation to certain parts (E.g leaves) When leaves fall off → Salt leaves mangrove. Pumps salt to one area to protect plant
  • Leaves; salt glands secrete salt that enters system. Glands release salt; can be blown/washed away
  • Roots; first line of defense; filter out incoming salt. Structure prevents much from entering

BLADDER SALTBUSH

  • Salt enters through roots and travels to leaves by xylem and phloem
  • Salt stored in vacuole of epidermal cells and moves to bladder cell
  • Bladder cell ruptures and salt is released
86
Q

Enantiostasis:

A

Survival mechanism; allows organisms to cope with extreme fluctuations in conditions in environments

87
Q

Estuary

A
  • Salt and water concentrations fluctuate daily (changes in tides affects salinity)
  • High tide→ salt into river→ salt water draws water out of cells by osmosis
  • Low tide→ sea water moves out, freshwater flows in (water moves into living tissue)
  • Organisms need to maintain normal metabolic functioning despite fluctuations
88
Q

Osmoconformers

A
  • Tolerate change by altering concentration of internal solutes to match external environment
  • Use small molecules to vary solute concentration in cells to match surroundings
  • E.g. Fiddler crab accumulates additional solutes in high salt, then pumps out excess when low salinity
89
Q

Osmoregulators

A
  • Avoid change in internal environment; keep solutes at optimal level regardless of environment
  • E.g. Mussels in rockpools close valves when tide it out (keeps salt concentrate same as seawater)
90
Q

Perform a first-hand investigation to gather information about structures in plants that assist in the conservation of water.

A

SHEOAKS:Needle like leaves→ reduces surface area, reduces water loss

EUCALYPTUS:Waxy cuticle→ reflects sun, reduces water loss by evaporation
Leaves hang vertically→ reduces exposure to sun

GREVILLIA:Small curled leaves→ Retain more water
Hairy leaves→ hair returns water, increases humidity

WATTLE:Grey colour→ Light colour to reflect sunlight, reduces evaporation
Hair on undersurface→ retains water

91
Q

Describe adaptations of a range of terrestrial Australian plants that assist in minimising water loss.

A

NEEDLE LIKE LEAVES: Reduce surface area and water loss. E.g. She-oakes

WOODY FRUITS: Less water loss than in fleshy fruits
E.g. She- oakes

LEAF CURLING:Leaves roll up forming cylinder→ reduces surface area, traps humid layer of air→ reduces water loss. E.g. Hummock grass

HANGING LEAVES:Leaves hang down→ reduces exposure to sun

SHINY/HAIRY LEAVES:Hairy surfaces on under surface→ reduces air movement, increases humidity over stomates→ reduces water loss
On upper surface→ reflects radiation from sun→ reduces heat gain

WATER DIRECTING LEAVES OR STEM:Stems and leaves are shaped so that water runs down them to roots
E.g. Acacia

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