Maintaining a Balance Flashcards
pH?
pH= a measure of the concentration of H+ ions in a solution. It is a measure of acidity, neutrality or alkalinity.
A decrease in 1 pH is a x10 H+ increase
0= most acidic
14=most basic
First-hand investigation to test the effect of: increased temp, change in pH and change in substrate concentration on the activity of named enzymes:
Increased temp and substrate concentration tested by timing the reaction rate of milk solidifying in the presence of the enzyme RENNIN.
Change in pH tested by measuring the amount of froth from the decomposition of hydrogen peroxide in the presence of enzyme CATALASE, breaks down into water and oxygen.
-specific enzymes work best at specific temp and pH. Substrate concentration increases reaction rate until saturation point.
Homeostasis:
- definition
- coordination?
- stages
- negative feedback
Homeostasis-the processes by which organisms maintain a stable environment for metabolism to function at optimal efficiency.
Maintains-temp, pH, glucose, salt etc.
Coordination-various parts of the body working together, led by the nervous and endocrine system.
e.g. In danger adrenalin makes body efficient and ready for action but nervous system detects the threat and triggers adrenalin release.
2 stages:
1) detecting change in stable state-organs called receptors or sensors
2) responding to (counteracting) the change- effector organs.
Input->receptor->control centre->effector->output/response
(Loop goes from receptor to arrow after effector)
Example if negative feedback loop
Low temp->cold receptors->CNS (hypothalamus)->effectors (increased metabolism, shivering, vasoconstriction, goosebumps->warm up
Range of temp life exists:
-70 to 120C but each species only has a narrow tolerance
Temp fluctuates more on land than in water cause water absorbs more energy
Example of endotherm vs ectotherm temp regulation adaptions:
Endotherm-regulate own body temp independent of ambient temp
Ectotherm-limited ability to regulate body temp, which changes with ambient temp.
Eastern red kangaroo Cold conditions: Physiological- increases metabolic rate Structural-vasoconstriction Behavioural-basking in the sun
Warm conditions:
Physiological- decreased metabolic rate
Structural-panting, exposed
areas of skin on forelegs to increase evaporative cooling of blood in this area (vasodilation)
Behavioural-nocturnal, licking forelegs to increase evaporation
Diamond Python
Cold conditions:
Physiological-lies on eggs and shivers
Structural- dark in colour (absorb more heat)
Behavioural-basks in sun, hibernation, migration
Warm Conditions:
Physiological- can shut down metabolism
Structural- vasodilation
Behavioural- nocturnal, burrowing
Responses of plants to temp change:
Orientation of leaves- increase or decrease sun exposure (eucalyptus leaves hang vertically)
Leaf fall
Seeds that survive bushfire
Vernalisation- plants that need to be exposed to cool conditions to produce flowers (think its spring)
Frost tolerant leaves
Reflective leaf surfaces
Heat shock proteins
Bulbs-plants die above ground by leave a bulb which can regrow when conditions become favourable.
Forms in which these are transported in mammalian blood?
- carbon dioxide
- oxygen
- water
- salts
- lipids
- nitrogenous waste
- other products of digestion
carbon dioxide- in plasma as bicarbonate ions
oxygen- oxygen-haemoglobin in red blood cells
water- in blood plasma, 90% water
salts- sodium, potassium, magnesium, chloride, sulphate and phosphate ions all in plasma
lipids- glycerides, phospholipids and cholesterol, PRIMARILY bound to plasma proteins, from digestive system to lymph
nitrogenous waste- urea and small amounts of ammonia and uric acids
other products of digestion-in amino acids, glucose, dissolved or suspended in plasma.
Changes in chemical comp of blood as it moves past:
- lung tissue
- skin tissue
- stomach tissue
- small intestinal tissue
- liver tissue
- large intestinal tissue
- kidney tissue
- endocrine tissue
lung tissue- +oxygen -CO2
skin tissue- -oxygen +CO2
stomach tissue- +water
small intestinal tissue- +amino acids and glucose (digested food)
liver tissue- +-glucose -unwanted substances e.g. Alcohol, vitamins, iron, excess lipids, excess amino acids
large intestinal tissue- +water, salts, vitamins
kidney tissue- -urea, excess water, salts, glucose (reabsorption of salt, water, glucose)
endocrine tissue- +hormones
Adaptive advantage of haemoglobin?
- oxygen is very insoluble in water, therefore other means of transport needed
- haemoglobin increases concentration of dissolved oxygen x100 (20ml of 100ml)
- haemoglobin made of 4 units of protein called ‘globins’. Towards the centre of each unit is the ‘haem’ unit, a ring structure with iron at the centre (bonds readily with oxygen but weakly, easily broken)
- red blood cells have no nucleus to fit more haemoglobin
- 4 active sites for oxygen to attach
First hand investigation: effect pf dissolved carbon dioxide on pH of water:
Greater H+ ion concentration= more acidic
Therefore more CO2=more acidic as:
Forms carbonic acid which breaks down to 2H+ + CO(3)2-
I.e. More H+ ions
First Hand Investigation: gather info on size of red and white blood cells
Using light microscope:
1) work out FOV of LP field by observing 2mm grid paper
2) use it to calculate FOV of HP field.
3) look at slides of white and red blood cells
Results:
WBC is 1.5x bigger (12 micrometres) than RBC (8 micrometres)
Structure of:
- arteries
- veins
- capillaries
Arteries:
- high pressure
- thick walls
- thinner=higher pressure
- elastic fibres expand and recoil with heartbeat
- carries blood away from heart
Veins:
- lower pressure
- muscle wall is thinner
- valves
- carries blood to heart
Capillaries:
- walls 1 cell thick
- diameter allows one cell through at a time
Arteries/Veins: endothelial layer-> elastic fibrous tissue->smooth muscle layer-> outer layer
Capillaries: just endothelial layer
Enzymes:
- role in metabolism
- chemical composition
- simple model to describe their specificity in substrates
-enzymes are biological catalysts, increase the rate of chemical reactions
Enzymes are not used up in the reaction
- enzymes are globular proteins in a specific shape. Contain an active site: 3-4 amino acids where the substrate will bind, forming an enzyme substrate complex.
- will only catalyse one type of reaction due to specificity of site
Shown by:
1) lock and key model: specific substrate fits specific enzyme, neither change shape. Does not explain all enzyme reactions.
2) induced fit model: substrate binds to enzyme and enzyme alters its shape to fit. Returns to original shape after reaction.
Other amino acids, “coenzymes”, aids substrate in binding to active site.
Why is oxygen essential?
Why is the removal of CO2 essential?
- oxygen is required for respiration, providing the necessary energy for cells to function i.e. Undertake necessary chemical reactions of the metabolism
- CO2 dissolved in water decreases the pH (i.e. More acidic) which causes enzymes to not function efficiently/be denatured. Therefore needs to be removed for homeostasis.
Technologies that measure oxygen saturation and CO2 concentration in blood
Pulse Oximeter:
-light emitting diodes (red and infrared) facing a photodiode through a translucent part of patients body (fingertip or ear).
Absorption at these wavelengths differs depending on oxyhaemoglobin and deoxyhaemogloblin content.
-oxygen saturation given as a percentage
Useful for:
- instant info
- constant monitoring (e.g. During an operation)
- non-invasive
- not as accurate
Arterial Blood Gas Analysis:
-electrochemicals used on blood sample from arteries. Give great detail on pH and gas concentration.
Useful for:
- very accurate
- invasive
- non-instant, needs to be sent to a lab for analysis
- records single moment in time
Artificial Blood:
- designed to increase blood volume and carry oxygen
- currently no A.B. used by doctors, some im clinical trials
Examples:
Polyheme-modified version of haemoglobin
-much better shelf life but with a circulation half-life of only 24hrs.
-still requires human donors
Per-fluorocarbon compounds-
- Used for oxygen carrying capacity
- manufactured entirely artificially (no risk of infection)
- 50% increase over plasma (still far behind haemoglobin)
- needs to attached to another molecule to be transported in the blood
Advantages:
- removes risk of disease carrying blood
- shelf life
- donor shortage
- immediate O2 transport
- no need for cross matching
Movement through xylem and phloem:
- transpiration stream
- translocation
Transpiration stream: upward flow of water from roots to leaves.
Uses:
Evaporation- in leaves results in low pressure in upper xylem vessels causes transpiration pull of water up
Cohesion-water molecules form hydrogen bonds
Adhesion-attraction of water molecules to walls of xylem vessels
Structure of Xylem Vessels- no plasma membrane for easy water movement
-pores in cell walls near leaves
Translocation:
1) high pressure of sucrose at source cell draws water from the xylem via osmosis
2) high water pressure comparative to low pressure near sink cell creates pressure flow
3) sugar is actively taken by the sink cell (requires ATP) out of the phloem
4) creates low solute concentration so water flows back to xylem via osmosis
Phloem:
Sieve element:
- sieve plate
- large empty lumen
companion cells:
-fulfils many chemical processes to keep sieve elements alive
Why should water concentration in cells maintain a narrow range for optimal functioning?
Water acts as a solvent for many substances and also is a transport medium for their distribution.
When dehydration occurs (6-10% water loss) plasma volume and the circulatory system may fail.
% water need depends on species
Why removal of waste vital to metabolism?
Waste like CO2 or NH3 affect pH when dissolved in water therefore affect homeostasis.
Structure of a kidney:
Look at diagram
- outer cortex (absoption occurs here i.e. Bowmans capsule)
- inner medulla (reabsorption occurs here e.g. Tubules)
- from nephrons goes to calyx, pelvis (collection occurs here), ureter
Structure of a nephron:
In order:
Glomerulus (cluster of capillaries) meets bowmans capsule- blood cells, platelets and plasma proteins are too large to pass through.
Proximal tubule- primarily glucose and amino acids (+some water and phosphates)
Loop of Henle- water and salt reabsorption.
Distal tubule-primarily water sodium and chloride ions (+some K+ and H+ ions.)
Collecting duct- urine (h2o, urea, phosphate and some Na+ Cl- ions)
-only permeable for water reabsorption with help of ADH
All surrounded by network of capillaries
Regulated by antidiuretic hormone and aldosterone.
Role of the kidney in the excretory system of fish and mammals:
Fish use kidneys for osmoregulation.
Mammals use kidneys for osmoregulation, excretion of wastes and reabsorption of needed salts
I.e. As aquatic animals have a continual supply of water to disperse waste in fish excrete NH3 and other wastes continually across the gills. In this way kidneys are not as involved in waste removal.
Terrestrial animals convert NH3 to urea and uric acid (less toxic , can be stored safely) to be excreted periodically, conserving water.
