Triple Content - Paper 1 Flashcards
What is calorimetry?
Food being burnt to see how much energy it contains
What are the equations to work out energy in food?
Energy in food = mass of water (g) x temperature change of water x4.2
Energy per gram of food = energy in food / mass of food
What is the brain and spinal cord?
- both part of the central nervous system
- brains made up of billions of interconnected neurones
- spinal cord is a long column of neurones that run from the base of the brain down the spine
What is the cerebrum?
Largest part of the brain divided into two Cabral hemispheres where the right hand side controls the left of the body and vice versa
-different parts are responsible for different thins like movement, intelligence and memory
What is the cerebellum?
Responsible for muscle coordination and balance
-located at the base of the brain
What is the medulla obolongata?
- connects the brain to the spinal cord
- controls unconscious activities like breathing and heart rates
How can the brain be visualised using CT scanners?
X-rays are used to produce an image of the brain which shows main structures but not functions, measures how much of the X-rays are absorbed.
-this can show diseased and damaged areas so if the patient has lost a particular function (e.g. sight)the function of that part of the brain can be worked out
How can PET scanners be used to visualise the brain?
- uses radioactive chemicals to show active parts as the scanner detects the gamma rays, more gamma rays more active part of the brain
- shows both structure and function
- by seeing inactive and active parts they are useful for studying disorders that change the brains activity
What are the limitations to studying the brain?
- hard to repair damage as CNS neurones don’t readily repair and scientists haven’t discovered a way to improve this
- hard to access and treat (not surgically possible for some parts)
- treatment can lead to further percentages damage
What is the eye?
An organ that is sensitive to light and responsible for sight
What is the cornea, lens and iris?
- Cornea refracts light into the eye
- lens also refracts light but focuses it onto the retina
- iris controls how much light enters the pupil
What are rods and cones?
- Rods are more sensitive in dim light but can’t sense colour
- cones are not so good in dim light but sensitive to different colours
What is the long sighted defect and how can it be fixed?
- unable to focus on near objects
- occurs when the lens is the wrong shape so doesn’t bend the light enough or when the eyeball is too short
- light is brought into focus behind the retina
- use glasses or lenses with a convex lens to correct it
What is the short sighted defect and how can it be fixed?
- unable to focus on distant objects
- when the lens is the wrong shape so bends light too much or when the eyeball is too long
- light is brought into focus in front of the retina
- use glasses of lenses with a concave lens to correct it
What is colour blindness and can it be corrected?
- defect where one can’t distinguish between colours
- caused when cones in the retina aren’t working properly
- no cure at the moment as cone cells can’t be replaced
What are cataracts and can they be corrected?
- cloudy part on the lens which prevents light entering the eye normally
- can cause blurred vision, less vivid colours and a struggle to see in bright lights
- fixed by replacing the faulty lens with an artificial one
What are the advantages of asexual reproduction (mitosis)?
- can produce lots of offspring quickly due to a fast reproductive cycle so can colonise an area quickly
- only one parent cell is needed so faces no issue for isolated organisms so can reproduce when conditions are favourable
What are the disadvantages of asexual reproduction (mitosis)?
-no genetic variation between offspring population so if the environment changes and conditions become unfavourable the whole population may be affected
What are the advantages of sexual reproduction (meiosis)?
- genetic variation so are more likely to survive environmental changes
- can lead to natural selection and evolution so a stronger population
What are the disadvantages of sexual reproduction (meiosis)?
- takes more time and energy to fewer offspring are made
- two parent cells are needed so creates problems for isolated organisms
What did Mendel do?
Used peas to observe how characteristics were inherited as they were easy to grow, has many traits which helped distinguish and traits could be tracked from generations
-took a while for his work to be recognised and fully explained due to a lack of understanding about genes, DNA and chromosomes
What is an example of one of mendel’s experiments?
- Crossed two different pea pants (one tall and one dwarf) and observed that all the offspring produced were tall
- he then bred these together and the resulting progenies where mostly tall but the small phenotype also appeared
- This showed that the unit for tall plants was dominant over that for small and that each had two hereditary units
What were mendel’s conclusions he came to?
- characteristics were determined by hereditary units (genes)
- these units were passed on from both/each parent
- these units can be dominant or recessive and if there is one of each the do any phenotype will appear
How do genetic variants in non coding regions affect phenotype?
Before transcription can happen, RNA polymerase has to bind to a region of non-coding DNA in front of a gene
- if mutations happen it can affect the ability of this binding making it easier or harder
- how well this binds affects how much mRNA is transcribed and therefore how much protein produced impacting phenotype
What are sex linked genetic disorders?
A faulty allele on the sex chromosome
Why are men more susceptible to sex linked genetic disorders?
- the Y chromosome is smaller than the x so carries fewer gees so most sex chromosomes are only carried on the X
- as men only have 1 X chromosome they often on have one allele for sex linked genes so it is more likely shown even if it is recessive
- women are more likely to be carriers
What is inheritance for blood groups like?
There are two allele for the blood gene meaning there are four potential blood types - A, B, O,A - and three different alleles - Io, Ia, Ib
(o is the universal doner and AB the universal receiver)
How do you get the different blood groups?
- Alleles A and B are codominant so if you have both these alleles you are blood group AB
- O is recessive so when combined with A or B your blood type is A or B
- blood type O appears when there are two recessive alleles- O and O
What did Darwin and Wallace do?
Came up with the theory of evolution by natural selection (VOSSAR)
- both travelled round the world and noticed variation within members of the same species and that those with beneficial characteristics were more likely to survive
- noticed that these characteristics could be passed onto offspring
- Darwin wrote the origin of species acknowledging the work of Wallace and explaining his theories
How have Darwin and Wallace influenced modern biology?
- classification based of organisms common ancestor and how closely they are related
- understanding the importance of antibiotic resistance and how to prevent it
- conservatism projects as understand the importance of genetic diversity to adapt to changing environments
What is the pentadactyl limb?
- a limb with 5 digits
- this is seen in many species showing they have similar bone structure but different functions (e.g. a hand and bat wing)
- provides evidence of evolution from a common ancestor
How do you conduct plant tissue culturing?
- take a piece of plant tissue from a rapidly growing area
- prepare a solid medium containing growth sugars, hormones and nutrients
- place the tissue on the medium
- store in a warm bright place to encourage cell division
How do you conduct animal/medical tissue culturing?
- separate the cells in a small piece of tissue by mashing or using enzymes
- prepare a solid or liquid growth medium contains sugars and nutrients
- pour a thing later onto a sterile medium of suspected in a liquid one
- store in a warm place to encourage cell division and growth
What are the advantages of tissue culturing?
- allows investigation into how cells respond to new medicines without risk to organisms
- can be used to protruded individuals of an endangered species or that don’t grow well from seeds (e.g. orchids)
- can replace damaged human organs
- viruses can’t replicate outside a cell and sterile mediums remove microbes so chance of disease
What are the advantages of GM organism?
- increase crop yield providing food for a growing population
- inset resistance (e.g. BT toxins which kills pests but isn’t harmful for humans animals and other insects)
- plants can grow better in poor conditions like drought
- can combat deficiency diseases like golden rice provides vitaminA
- Herbicide resistance
What are the disadvantages of GM organisms?
- may have unforeseen bad effects on the wild
- may reproduce with wild plants passing on resistance so GM may become ineffective
- some believe eating GM foods could have bad health impacts
- biological controls have long lasting effects and less hateful impacts
- people still can’t afford food so poverty must be tackled first
- sometimes poor soil is the main reason for failed crops
What are viruses?
- organisms that can’t divide on their own so take over a living cell
- often considered non living and exist in an inert stage outside the host cell
- consist of a strand of nucleic acid(rna or dna) surrounded by a protective protein coat (capsid)
- some may also have a further membrane envelope or a tail section
What is the lythic pathway (usually first stage of life cycle)?
- virus attaches itself to a specific host cells and insects it’s genetic material into the cell
- the virus uses proteins and enzymes in the host cell to replicate its genetic material and produces and assembles the components of a new virus whilst killing the host cell”s DNA
- host cell splits as becomes overcrowded releasing the new virus which infects more cells
What is the lysogenic pathway?
-the injected genetic material is incorporate into the genome of the host cell
-viral genetic material gets replicated along with the host DNA every time the host cell divides (but the virus is dormant and no new ones are made)
-eventually a triggers (e.g. presence of a chemical) causes the viral gm to leave the genome and enter the lythic pathway
the
-passive and non-virulent prophage replicates too. This may alter the cell’s characteristics, but it does not
destroy it.
What is the waxy cuticle physical plant defence?
- Provides a barrier to stop pathogens entering or damage from pests
- stops water collecting on the leaf reducing the risk of infection of water transferred pathogens
What does the cell wall physical barrier do to help plant defence?
-made of cellulose and stops pathogens once they’re past the waxy cuticle
What chemical barriers do plant defences have?
- produce chemicals called antiseptics which kill pathogens (bacterial and fungal) and a chemical to deter pests from feeding on them
- e.g. aspirin relieves pain and fever and found in willow tree bark
- quinine was used to treat malaria and found in chinchona tree bark
How are plant diseases detected by observation in a lab?
-by changing environmental condition and observing ant change in the plants symptoms one can see if the plant is diseased or if the symptoms were due to something else
How are plant diseases detected by distribution analysis in a lab?
Pathogens spread in different ways so pathologists can analyse the distribution of diseased plants to indent oh the kind of pathogen involved
-e.g. random distribution could suggest and airborne pathogen
How are plant diseases detected by diagnostic testing in a lab?
- identifies the presence of specific pathogens
- detecting antigens or DNA of pathogen in the plant allows the pathogen to be identified and disease diagnosed
What are the benefits of immunisation?
- big outbreaks of disease (epidemics) can be prevented and eradicated if a large percentage of the population is immunised
- herd immunity where you are less likely to fall ill as if more people are immunised there are fewer carriers of the disease to pass it on
What are the cons of immunisation?
- doesn’t always work
- bad reactions to a vaccination
What are monoclonal antibodies?
Produced from lots of clones of a single B-lymphocyte making them identical and they will only target one specific protein antigen
What are the stages of making monoclonal antibodies?
- a mouse is vaccinated to start the formation of antibodies
- spleen cells (lymphocytes) that from antibodies are collected from the mouse in an operation
- these are fused with a tumour cell called myeloma cells as they grow and divide lots as lymphocytes wouldn’t on their own
- this creates hibridoma cells which are collected and purified
How are monoclonal antibodies used to locate blood clots and cancer?
- designed to bind to these cells/proteins
- attach to a radioactive element and inject into the body
- take a picture using a camera which detects radiation and a bright spot should indicate where the clot or tumour is
- useful to see side, location and if it is spreading
How are monoclonal antibodies use to target cancer cells?
- an anti cancer drug is attached to a monoclonal antibody and given to a patient through a drip
- they target specific cells as only bond to the tumour markers(hug specificity) killing the cancer cells but not other nearby cells
- these are better than radiotherapy as that can effect normal body cells as-well and there are more worse side effects. It also reduces the amount of drug needed due to their high specificity
What are drawbacks of monoclonal antibodies?
-due to their monospecificity it limits their application as minor changes in their antigenic epitope May effect their ability to bind and function
How are monoclonal antibodies used for pregnancy tests?
A hormone HCG is found in the urine of pregnant women and pregnancy test sticks detect this
-this is because the strip has some antibodies to the hormone stuck to it and the part you pee on has antibodies with blue beads attached
How do you know if the you are pregnant using monoclonal antibodies?
- if pregnant the hormone binds to the antibodies and the urine moves up the stick carrying the hormone and the beads
- these bind to the hormone on the strip turning it blue (positive result)
- if not the urine still moves up the stick carrying the blue beads but there’s nothing to stick the blue beads onto the strip so doesn’t go blue
What are stages 1 and 2 of the aseptic technique?
-Petri dish and growth medium must be sterile before use so place in an autoclave machine which uses steam at high pressures and temperatures to remove microorganisms
-before being used to transfer bacteria, sterilise the inoculating loop by passing it through a hot flame
spread)
What are stages 3, 4 and 5 of the aseptic technique?
- liquid bacterial culture should be kept in a culture vial with a lid which should only be removed when transferring bacteria (this avoids microbe contamination and too much liquid mean they will spread)
- tape the lid on to remove airborne microbes entering
- strobe upside down so drops of condensation don’t fall onto the agar
How do you investigate the size of the inhibition zine in the aseptic technique?
- visually, the larger the inhibition zine the more bacteria killed to the more effective the antibiotic is
- or using the area (area of a circle where radius is half diameter)
LEARN TRANSCRIPTION AND TRANSLATION
On separate paper flash cards
What are the symptoms of the lifecycle of viruses?
- no symptoms for lysogenic as occurs after the viral infection but viral DNA remains in the cell and can do permanently
- in lythic it takes over the cells metabolic activities so lots of symptoms
How do you test for starch?
Just add iodine solution
-if starch is present it should go from orange to blue/black colour
How do you test for lipids?
- shakes the substance with ethanol until it dissolves then pour into water
- if lipids are present they will precipitate out to form a milky emulsion
How do you test for proteins?
- add a few drops of potassium hydroxide solution to make the solution alkaline
- then ass copper sulphate solution (blue)
- if protein is present it should turn purple, if not stays blue
