Experimental Methods Flashcards
Accuracy
How close a measurement/reading is to its true value
Systematic errors
Faulty instruments or flaws in experimental procedure - repeated consistently
Random errors
Unexpected environmental changes - different each time experiment is carried out
Precision
How similar repeats/readings are to each other ; greater number of decimal places = more precise
Reliability
Experiments are repeated to ensure reliability/repeatability of results
Validity
Other variables are identified and controlled to ensure validity
Different combinations of genes/alleles
2 to the power of number of homologous chromosomes - meiosis
What vessels have sphincter muscles
Arterioles
Lub dub
Closing of av and then closing of semi lunar
Increase co2 concentration
Decreases pH
Chloroplasts vs mitochondria comparison
Chloroplasts bigger than mitochondria
What are stem cells in plants
Pluripotent
Amylase breaking down starch
Into maltose
When adding a stain…?
Place stain at edge of sample and not the centre
Remove excess stain using blotting paper
45 degrees
What does using more than one stain do?
Improves contrast
Ensure stain
COVERS WHOLE SAMPLE
Eukaryotic vs prokaryotic
Eukaryotic contains membrane bound organelles
Capture recapture formula
(Number in 1st sample) * (number in 2nd sample)
DIVIDED BY NUMBER IN 2ND SAMPLE THAT IS MARKED
Action potential type of response?
Positive feedback loop reinforces influx of Na+ ions
Phosphate group in ATP
ATP contains 3 phosphate groups
Why do we want dna replication to produce two new genetically identical strands
Minimises risk of mutations - have to be genetically identical
Test for starch
Iodine SOLUTION (+ potassium iodide)
Reducing sugars test
Benedict’s solution + heat
What type of sample is Benedict’s/biuret
Alkaline
Why is taking the mean into account a bad thing sometimes?
Since it includes any outliers while mode does not
Mitosis purpose
Gametes from haploid cells
Clonal expansion
Making new stem cells
What does bile do?
Emulsify lipids physically breaking them down into smaller droplets and increasing SA
Inspiration
External intercostal muscles contract
Effectors
Cannot be bones - they will be the muscles that move the bone
How is carbon dioxide mainly transported around the blood
Hydrogencarbonate
Companion cells adaptation
Lot of mitochondria
Adaptation of gills of fish
Stacked against each other - movement is stopped - slows down rate off low thus increases diffusion
Viewing the heart
Lateral cross section - staining/microscope
Haemoglobinic acid
H+ + Hb forms haemoglobinic acid ; acts as a buffer
Casparian strip
Partially permeable membrane - filters it through ; toxins are removed
How do assimilates move through phloem
By mass flow
They move into the phloem through plasmodesmata (H+ ions)
Examples of sinks
Root
Meristem - rapidly dividing
Phagocytes
Macrophages and neutrophils - macrophages from APCs and neutrophils carry out phagocytosis
Membrane functions
Site of chemical reactions - ATP synthase etc
Compartmentalisation - concentration gradients/stable environment
Allow substances to enter and leave (partially permeable)
Cell communication/signalling glycoproteins
Coenzymes
Vitamins
Cofactors
Minerals
Which way does water vapour flow through a leaf?
Palisade mesophyll - spongy mesophyll - air spaces
When measuring cell size in a microscope
Take repeat measurements at the end and calculate a mean
Photorespiration
At higher temperatures - oxygen competes with carbon dioxide for active site of RUBISCO thus less GP (and thus TP) produced ; RuBP is not regenerated
Less co2
Less carbon fixation - less TP made ; need for ATP and reduced NADP is lower which slows down light dependent stage ; ATP and reduced NADP accumulates and leads to end product inhibition
Fats
Are also non-polar ; thus do not affect osmotic potential
When you are removing glucose from free ends what are you doing
Hydrolysing glucose monomers
Cellulose property
Inert
Synthesis of polynucleotides/triglycerides
Involves formation of ester bonds
Triglycerides/lipids
High ratio of hydrogen to oxygen
Benefit of animal fats being saturated/harder
Role in protection/insulation as well as energy storage
Differences in species how determined
Cytochrome C
RNA polymerase
How to improve uncertainty
Use more precise equipment callipers etc
Problem with using colorimeter on a leaf
Accessory pigments/chlorophyll are also present which may interfere
Pressure in lymph
Low
Primary defence mechanisms
Blood clotting
Small isolated populations
Can be easily wiped out by disease
Disadvantage of no organelles in erythrocytes
No respiration from mitochondria
Does not divide
Protein synthesis
Explain differences in size of organelles/specimens?
One’s been cut longitudinally the other transversely
Some organelles are undergoing mitosis/beginning to divide
Purpose of mitosis (apart from growth/repair/AR)
Maintaining set number of chromosomes
Advantage of umbilical cord stem cells
Easier to extract/harvest
Can be stored for the future
Trunk swelling outside
Hydrostatic pressure has increased somehow water comes into the cells
Or cells are rapidly dividing
Lignin in xylem
Waterproofing
Glycoproteins
Cell adhesion - big role in holding them together in tissues
Artery collagen
Thick - strengthens against pressure of the blood
Smooth muscle arteries
Contract - direct how much blood flow
Maintain pressure alongside elastin - stretche/recoil
Lumen
Smooth - reduces friction as blood flows through
Coronary heart disease factors
Saturated fats
Obesity
Age (as you get older)
Diabetes
Gender
Risk factors for type 2 diabetes
Age
Genetic history
Gender - more common in males
Obese
Sedentary lifestyle
Adaptations to respire longer anaerobicallu
Tolerant to lactate/low ph/high CO2 concentration
Greater affinity for oxygen
Faster diffusion of ions in action potential
Faster depolarisation
Shorter refractory period
Importance of refractory period
Ensures that action potentials are discrete events and stopping them merging into each other
Impulses can only travel in one direction
Tissue that lines proximal convoluted tubule
Columnar epithelial
Purpose of microvilli in PCT
Increase SA allowing greater volume of filtrate to be reabsorbed
PCT
Selective reabsorption - using Co-transport/active transport
Water follows by osmosis so concentration of ions/urea in filtrate increases
Anticoagulants haemodialysis
Stop blood clotting in the machine
Afterwards they are removed to allow blood to clot normally
Why are cells packed together in PCT
No fluid can pass between the cells ; must pass through cells
Urethra
Leaves body - excretion
Ureter is from kidney to bladder
What to ensure when doing photosynthesis experiments?
Ensuring CO2 is in excess
Erector pilli response in fight or flight
Makes the animal look bigger
Hypothalamus nervous system?
Also a part of nervous system - osmoreceptors are nervous system ; NEGATIVE FEEDBACK CYCLE
Atrial fibrillation
Has taller QRS complex - shorter squiggly lines between them
Why do aerobically fit people have smaller heart rate?
Increased stroke volume
Thicker heart muscle
Increased ventricular volume
How do calcium ions go back into sarcoplasmic reticulum
Via active transport
High respiratory quotient like glucose vs fats (low RQ)
More oxidised - requires less oxygen
Fatty acids are less oxidised - low respiratory requiring highest amount of oxygen for complete oxidation
Where do chloroplasts store food?
Starch grains
What type of light can penetrate furthest through water
Light of shorter wavelength
Reasons for why you need to work fast in an experiment
Minimise evaporation of any solvent/liquids - reduce degradation of pigments
Why is ice cold ethanol and sucrose used?
To slow down rate of enzyme reaction and prevent damage to chloroplasts
What does high temperature do to chlorophyll pigment
Destroys chlorophyll pigment
What is a limiting factor?
A factor that determines the rate of the reaction at lower levels
Microorganism population growth
Original population * 2^n
Where is light chain on antibody
OUTSIDE BIT
Primary immune response
Relatively slow production of a small number of correct antibodies the FIRST TIME A PATHOGEN IS ENCOUNTERED
How to increase reliability?
Calculate a mean - measure more cells ; discard anomalous ones etc
What accepts hydrogen in anaerobic respiration yeast?
Ethanal
Advantage of anaerobic respiration?
Allows glycolysis to take place
Release of insulin
Low glucose concentration - resting potential - K+ ions can move out of KATP channels - maintains resting potential
High glucose level - glucose moves in via transporter and metabolised to produce ATP via aerobic respiration ; inhibits opening of potassium channels - closes K+ ions moving out ; causes membrane to depolarise and Volta gated ions can move in ; bind to secretory vesicles allowing them to fuse with plasma membrane and release by exocytosis
Non specific methods
Blood clotting
Skin - sebum ; flora
Chemicals - mucus/lysozymes
Mast cells release
Histamines (heat+redness) and cytokines attract phagocytes
Clotting factors
Turn prothrombin into thrombin - fibrinogen into fibrin - mesh together + collagen and seal the wound
Positive feedback
Seed germination
Gibberellins - released ; digestive enzymes break down food stores to release glucose for growth
Cell elongation
Auxin binds to receptor - H+ ions pumped in - low ph levels causing cellulose become more flexible/stretchy and absorbs water
High auxin concentration
Apical shoot growth
Less lateral shoot growth
Low auxin concentration
Low apical shoot growth
More lateral shoot growth
Why May you want fewer gibberellins in plants?
Less waste
Prevent crop damage by bad weather
Chlorosis
Plant environmental variation causes change in phenotype - leaves look yellow
Causes of chlorosis
Lack of light - turn off chlorophyll production to conserve resources
Mineral deficiencies - lack of iron or magnesium - plant cannot make chlorophyll
Virus infection - interfere with metabolism
Codominance
2 different alleles for a gene both equally as dominant thus both expressed (pink flowers - red and white)
Blood group
IA IB - codominant
IO - recessive
23rd Pair
Sex chromosomes - XX females XY males
Males more susceptible to sex linked diseases?
MALES ON,Y REQUIRE ONE ALLELE ON THE X CHROMOSOME TO BE RECESSIVE ; FEMALES WILL HAVE A DOMINANT ALLELE ON THE OTHER X CHROMOSOME
Haemophilia
No clotting protein - very slow process
Faulty haemophilic gene X^h
I^o
No antigen on the surface of RBCs hence they are universal donors - no immune system rejecting that RBC since there is no antigen
Dihybrid
Both genes inherited as separate units
Dihybrid
2 genes - each gamete - 2 alleles
Unexpected ratios due to
Autosomal linkage (no crossing over occurred to separate these genes)
Random fertilisation
If chi squared significant
Then linkage/epistasis has occurred
Epistasis
A gene on a particular chromosome is expressed producing a protein which stimulates or inhibits gene B expression
INTERACTION OF GENES AT DIFFERENT LOCI
Dominant epistasis
Requires gene A to be AA or Aa to produce protein to express B
Recessive epistasis
Chromosome A produces aa (recessive) - does not produce protein and thus B not expressed
Assumptions of hardy Weinberg
Assuming random mating
No mutations
Large population size (migrating)
No selection pressures (evolving)
What is hardy Weinberg
In a stable, non-evolving population - allele frequencies stay constant
4 major factors that affect evolution
Mutation - genetic variation ; advantageous allele
Changes to population size - density dependent factors (competition - affect size)/density independent factors (regardless of size - climate change/natural disasters)
Genetic drift - prevalent in small populations ; random mutation/selection pressure
Gene flow
Alleles from one place to another - migration (seasonal often) SMALL CHANGE
Genetic bottleneck
LARGER change - irreversible change to total number of alleles ; natural disasters - affects future generations - alleles decreases
Founder effect
Genetic drift - mutation from small gene pool that gives favourable gene which can outcompete rest of population forming a new colony
Founder effect
A few individuals’ alleles eventually form whole new populations
Selection of favourable alleles (4th factor affecting evolution)
Sexual selection ; more alleles that promote mating success (passing on this allele)
Natural selection - more alleles that promote survival success
Stabilising selection
NORMAL DISTRIBUTION
AVERAGE PHENOTYPE IS SELECTED (SPIKE IN MIDDLE) ; BABY WEIGHT ; UNDERWEIGHT/OVERWEIGHT LESS LIKELY TO SURVIVE - PASSING ON GENE FOR BABIES WITH NORMAL WEIGHT TO BE BORN
Directional selection
One extreme is favoured - industrial evolution selection pressure of moths ; population of darker moths increases
Disruptive selection
Both extremes are selected
Duller feathers left alone survive longer
Bright feathers too frightening left alone survived longer
Can mate and pass on genes
Speciation precursor
Always underlying genetic variation
Allopatric
Physical barrier has separated population subject to different selection pressures - different genotypes/alleles are favoured (selected and survived and passed on - hence genotype and phenotype more prevalent)- CHANGE IN ALLELE FREQUENCY due to new habitat
Allopatric speciation
Just happen over several generations
Sympatric speciation
Happens in same habitat - mating preferences/disruptive selection causing new species to form
Much rarer
Physically cannot recognise other members of same species due to variation
Only reproduce with those that animals could recognise (selective breeding is similar to sympatric speciation)
Faeces
COLOURED FROM BILE
How to show uncertainty
If error bars overlap
Collagen
Glycine
Cysteine
Has many disulfide bridges
As you increase temperature of cell surface membrane
GAPS BETWEEN PHOSPHOLIPIDS INCREASE - PERMEABILITY INCREASES
How does frosting/defrosting impact cell surface membrane
Ice/water expansion damaged membrane (punctures it) increasing permeability
Why are there two tubes in a respirometer?
Compensate for temperature changes by evening out the pressure on both sides
Why is there a filter paper with KOH solution in respirometer
Increase SA for CO2 absorption
Rate of movement of water in pathways?
Movement of water in symplastic is slower than apoplastic
Pancreatic exocrine function
Pancreatic juice into duodenum/digestive enzymes to epithelium in a vessel
If asking for other possible factors always mention
Possibly epigenetics factors
Other underlying health diseases
Downside of stem cell
Risk of cancer
Liver cells adaptation
Thin/flat cells
Increase rate of diffusion
Fenestrations also increase permeability
At the sinks of plants
Sucrose is converted back into glucose to be used for respiration/stored as starch
Myosin molecules
Fibrous protein molecules with a globular head
What required ATP in muscle contraction
Return of calcium ions into sarcoplasmic reticulum and return movement of myosin head that causes actin filaments to slide
How is ATP supplied for muscle contraction
Aerobic respiration takes too long ; anaerobic respiration is still 10 seconds - phosphocreatine is a molecule stored by muscles that can be used for rapid production of ATP
Equation of phosphocreatine
Phosphate ion from phosphocreatine + ADP -> ATP + creative
When is phosphocreatine utilised
Muscles of a sprinter - continuous contracting until mitochondria is able to supply ATP ; afterwards once used up then rate of muscle contraction must EQUAL rate of ATP production (from both aerobic and anaerobic respiration)
Cardiac muscle
Have intercalated discs help in contraction + striated
Smooth
Pupil size
Bladder
Digestive systems
Bronchioles etc
Myofibrils
Long cylindrical units
Whenever an ion binds
CONFORMATIONAL CHANGE
Cardiac output
Stroke volume * heart rate
Formation of urea equation
Requires co2 and nh3 ; water is what is converted to urea when going from arginine to Ornithine
What happens to lactate in anaerobic respiration
Broken down by oxygen in the liver (oxygen debt) turned into glucose
Functions of liver
Formation of urea
Storage of glycogen
Detoxification
Urea vs ammonia
Urea is less soluble and less toxic
Hormone metabolism
Protein hormones like insulin and glucagon are hydrolysed into amino acids which are then converted into urea
Peptide hormones
ADH
Dehydrogenase
Used wherever there is a transfer of a hydrogen atom from an organic molecule to an inorganic one
What substances ionise in respiration
Pyruvate
Citrate
OAA
What occurs at the cristae
OXIDATION OF NADH
Where is proton gradient in chloroplast
Thylakoid membrane
Diameter tubing questions
Figure out surface area of bubble using RADIUS given
Then multiply by length/any rate given
End point of dcpip
Pink colour - not colourless
Increase in concentration for every 1 unit
Final value/initial value divided by (difference of NUMBER OF UNITS)
Why is it best not to add indicator to the test tube
As it may affect the progress of the reaction
How to improve validity of sample taking
Take samples at more frequent intervals
How to increase validity if an experiment
Add buffer to control pH
Little variation
High repeatability
What do error bars do
THEY OVERLAP
Gas collected
= water displaced
Commercial effect of inhibitor
More inhibitor wastes money
Planning an experiment
Variables
Repeatability (quantitative processing for example)
Risk Assessment
Scientific apparatus
How would water on the leaves affect transpiration rate
Water could block the stomata
Hydrophytes
Water lost is easily replaced - plentiful water
How does ph affect rf values
Ph of the solvent influences rates at which X and Y migrate
How high should solvent line be
1 cm away from amino acids to prevent the acids dissolving
How to improve resolution of TLC
Use longer filter paper
How does increase temperature affect heart rate?
Increases heart rate to get rid of excess heat by dilating arterioles (and thus capillaries)
Why are daphnia used?
Fewer ethical considerations
A fitter person
Has greater stroke volume
What do gibberellins do?
Seed germination
Prevent leaf abscission
One plant variable hard to control
Surface area of the leaves
When using sensors
Ensure they are the same distance away
Why are respirometer flushed/cleaned out?
To remove any microbial growth/reset it back to zero - they are washed with hot water
Using colorimeter
Objective = less bias
To reduce uncertainty
Use callipers/more precise equipment
Practical error with water potential
Could be inadequate drying
Repeats =
Reproducibility
How do H+ ions affect cell membrane?
They affect ionic bonds of the membrane proteins
What do free divers have
High co2 tolerance
Why do we calculate a mean
To reduce uncertainty (anomaly) - reduces random error too
Reproducibility
Similar results produced by different investigators with different equipment
Not touching the TLC plate
No contamination of oil/bacteria from fingers
Negative control
One thing you change to ensure that it is the variable you are changing that is causing the change - add buffer/boil yeast whatever
Tidal volume
Normal breaths in and out
Everything except - volume
Everything except residual volume is = vital capacity
Ribcage cavity
THORAX
In the leaf of a plant
The phloem is straight after the xylem - IGNORE CAMBIUM
When asking for serial dilutions
Make sure to see if it’s ORIGINAL 1 mol dm^3
Cardiac muscle
Is branched and interconnected
Cardiac muscle
Is branched and Interconnected
Where is ATP needed in muscle contraction
Break cross bridging and detaching myosin from actin - allows for muscle relaxation
Phosphocreatine ATP
Runs out in a few seconds
Glucocorticoid
Regulates carbohydrate metabolism
Why are computers good
Continual data collection
Intracellular reactions
Catalase breaking down hydrogen peroxide
Extracellular reactions
Trypsin or amylase
Membranes
Sites of chemical reactions
Active transport explain
Molecule comes along binds
Causes hydrolysis of ATP to ADP and pi
Inorganic phosphate ion binds to carrier protein causes change of shape against concentration gradient
Released and then ADP + inorganic phosphate creates ATP again
Neuromuscular junction
Between neurone and a muscle - they can only ever be excitatory while cholinergic synapses can be both excitatory or inhibitory
Elastic fibres
Present in all parts of the gaseous exchange system
Support in insects
Chitin around tracheae - impermeable to gas exchange
Like c shaped cartilage in trachea of humans
Water in tracheoles
Dissolve and easily DIFFUSE ACROSS MEMBRANES
A control set up is one
WITHOUT THE INDEPENDENT VARIABLE - SHOWS THAT IT IS IV THAT US CAUSING CHANGE
How do you improve reliability?
Large sample size
Function of Hepatocytes
Produce bile - breakdown of haemoglobin in erythrocytes
What happens in pelvis of kidneys
All the urine collects before travelling to bladder
What does ADH do?
Increases PERMEABILITY to water
Monoclonal antibodies
Coloured dyes
Creatinine
Breakdown product of muscles - directly measures kidney failure
Kidney failure can lead to
Electrolyte imbalance
Excess Urea
Refractory period responsible for
Producing discrete impulses - each one separate
Ensures that they are unidirectional
Limits the number of impulse transmission
Abscission caused by
Lack of auxin
Promotes ethene production
That is what causes enzymes breakdown of separation layer/abscission zone
Antifreeze
ABA produces antifreeze to prevent the cytoplasm in cells from freezing
Weed killer uses
Auxin
Also in seedless fruit x auxin
At a neuromuscular junction
End point of action potential
Photo system = light harvesting + reaction centre
PSII
700 nm
In respiration Krebs cycle
Per cycle 1 atp produced
Ame length of dna bases
Must be a mutation - same number of bases
TLC
Adsorption onto stationary phase
Soluble in mobile phase
When does dehydrogenation occur?
Whenever NADH or FADH2 is produced is when dehydrogenation occurs - ATP produced
