Wrong Questions - B4 to B6 Flashcards
What is the role of the carbon cycle?
- maintain the flow of nutrients and habitats
Why happens when water evaporates and condenses?
- forms water droplets which help to make clouds
Why is not all of the energy of the sun transferred to the biomass of the plant?
- only 10% is converted to body tissue by consumers
- light availability, temperature and light reflected means that half of the energy is taken away
- rest of it adds to biomass
How is energy lost by the consumers?
- excretion - urine
- egestion - not all of it is digested such as waste faeces
- respiration - movement and transferred into the surroundings as thermal energy
- not all of the organism eaten - bones or roots
How does the temperature of an area affect the organisms in an area?
- Temperature affects enzymes that control metabolic reactions
- Plants develop more
rapidly in warmer temperatures (as their metabolism will be faster), as do cold-blooded
animals (ectotherms) - Warm-blooded animals (endotherms) are less affected by their
external temperature
How are plants involved in the carbon cycle?
- take in carbon dioxide in photosynthesis
- give out carbon dioxide in respiration / when decay
- pass on carbohydrates / proteins / fats to animals / when eaten
What is the structure of a virus?
- protein coat / protein outer layer
- (containing) genetic material
What is a variation?
- difference within a species
What is a parasite?
- lives on / off / in a host / living organism
- causing it harm
How does smoking increase the risk of cancer?
- substances burnt increases the chances of mutation of the DNA sequence
What do start codons do?
- triggers transcription
- in the non - coding section of DNA
Describe the history of genetics?
- Mendel - characteristics passed on from parents, by genes, Recessive and dom
- Meischer - Nuclien = acidic substances in nucleus (DNA)
- Avery - bacteria passed on disease-causing genes from one to another
- Chargaff - same no. of C-G and A-T
- Franklin and Wilkins - photographed DNA crystals
- Watson and Crick - discovered double helix shape of DNA
- 1953 to 2000 = genetic engineering and genetic diseases
- 2003 = genome project
- now = gene therapy
How do mutations occur?
- alters the base
- inherited or spontaneous
How do plants produce seeds?
- pollen (male) fuses with the egg cell in the ovule
How does meiosis occur?
- DNA unzips, free nucleotides join, replicates
- homologous chromosomes pair together, crossed and genes swapped
- pair lines up in the centre and splits = 2 diploid cells
- 2nd div = line up and split as each arm pulled = 4 haploid gametes
- genetically varied
Where does meiosis occur?
- in gonads (testes or ovaries) = 23 from male and 23 from females
How did Darwin’s theory lead to The Theory of Evolution?
- travelled to the Galapagos Islands
- noticed that different islands had different finches
- birds were closely related, but their beaks and claws had different shapes and size
- observations = realised that the design of the finches’ beaks was linked to the food available on each island
- concluded= bird born with a beak more suited to the food available would survive longer than a bird whose beak was less suited.
- Therefore, it would have more offspring, passing on its characteristic beak.
- Over time the finch population on that island would all share this characteristic
- Darwin called this process natural selection
What is classification?
- sorting organisms into groups with similar features depending on their similarities and differences
What is the reason for using bacteria to produce hormones?
- bacteria reproduce rapidly
- can quickly produce many bacteria containing the new gene
How is malaria caused?
malaria is caused by protist, and mosquitos at as vectors and they pick it up when they feed on infected animals, every time mosquito feeds = infects by inserting protists to animal’s blood vessels = malaria can cause repeating episodes of fever and can be fatal
How do wbc eat microorganisms?
- phagocytes have a flexible membrane and have lots of enzymes
- enables them to engulf foreign cells and digest them-
- phagocytosis
How do wbc produce antibodies?
- done by B-lymphocytes
- every invading pathogen has unique antigens on its surface
- wbc comes across foreign antigen = produce proteins called antibodies to lock onto the invading cells
- antibodies are specific to that type of antigen
- antibodies are produced rapidly and carried around the body to lock on to similar pathogens
- antibodies help the phagocytes find pathogens so they can engulf them
- some wbc are called memory cells - stay around in the blood after pathogen is gone so if the person is infected with the same pathogen again = the white blood cells rapidly produce the antibodies to destroy it - naturally immune to that pathogen
What are monoclonal antibodies?
- produced from lots of clones of a single white blood cell = identical and will only target one specific protein antigen
- produced in the lab by using hybridomas (fusion of lymphocyte and tumour cell)
How are monoclonal antibodies produced?
- genetically modified mice injected with chosen antigen
- body produces antibodies to specific antigen (using lymphocytes)
- lymphocytes collected and fused with myeloma cells to make hybridoma (can’t survive out of body)
- myeloma cells reproduce indefinitely
- as hybridoma cells reproduce = form clones
- each clone will produce required antibody which is harvested = monoclonal antibodies
How do vaccinations work?
- they involve injecting dead, inactive or weakened pathogens into the body
- they carry antigens so even though they are harmless, they still trigger an immune response
- the wbc (lymphocytes) produce antibodies to attack them
- some of theses wbc remain in the blood as memory cells so if live pathogens of the same type ever appear, the antibiotics help destroy them will be produced immediately before symptoms show = immunity
What are drugs?
- substances which alter the way the body works (some medically used - penicillin and some dangerous if misused)
- this is why some can’t be bought over the counter and only on prescription
What are antibiotics?
- drugs that kill bacteria without killing your own body cells (diff types for each range of bacteria)
- many produced naturally by fungi or other microbes (penicillin = mould)
- grown at large scale and useful for clearing up bacterial infections but don’t kill viruses (not all microbes are harmful)
- some bacteria are naturally resistant to antibiotics so misuse has increased the rate of development of resistant strains and MRSA is the best-known antibiotic resistant strain
What are antivirals?
- drugs that destroy viruses (specific so act on 1 type of virus) and most stop them from reproducing
- might kill virus by = blocking virus from entering host cell, prevent virus from releasing its genetic material and prevent virus from inserting its genetic material in to host DNA
- difficult to produce as virus use the host cell to replicate so hard to target virus without damaging cell
What are antiseptics?
- chemicals that destroy microorganisms or stop them from growing and don’t harm human tissue (alcohol and iodine) = diff antiseptics for diff microorganisms
- used in external living surface (to kill/ neutralise any type of pathogen) to help clean wounds and surfaces (prevent infection rather than treat it) and kills pathogens on non-living surfaces =disinfectant (household products)
- used in hospitals and surgeries to try to prevent the spread of infections like MRSA
What happens after a potential drug is identified?
- drugs are developed further by preclinical tests in the lab to see how it behaves
- preclinical tests = test on live cells, bacteria and tissue culture
- but you can’t use human tissue to test drugs that affect whole/ multiple body systems
- e.g testing drug for blood pressure must be done with a whole animal (one with intact circulatory system)
- many fail as this stage as may damage cells or not work
What happens after clinical trials?
- Animal testing =must pass with 2 species before human trials (some think it’s cruel and others think it’s the safest way)
- 3 Rs principal:
- reduction = use a small number of animals present
- refinement = improve experiments to avoid unnecessary suffering and improve animal care
- replacement = replace animals with other techniques (e.g cell cultures)
What are the two groups of people testing drugs?
- -one is given new drug and other is given a placebo (substance that looks like the real drug but doesn’t do anything)
- this is done so scientists can see actual difference the drug makes, allowing the placebo effect
- they are double blind trials so the patient and scientist/ doctor don’t know if they’re getting the drug or the placebo until the all the results have been gathered
- this is so doctors monitoring the patients and analysing the results aren’t subconsciously influenced by their knowledge
- to allow for the placebo effect in patients (where people start to feel better just because they expect the treatment to work even though the treatment isn’t doing anything)
What are the chemical defences of plants?
- produce antimicrobial chemicals or kill pathogens/ inhibit their growth (antibacterial chemicals)
- antimicrobials are chemicals that act against microbes
- produce saponins (destroys cell membrane of fungi/other pathogens)
What are the 2 lab techniques to find pathogens of plant diseases?
DNA analysis (PCR)
- all living things have a unique genome
- use DNA fingerprinting to identify the pathogen we have based on the DNA present
- parts of the DNA complementary to the pathogen are used as primers (template) and any dna that matches is copied over and over again and if the pathogen is present lots of its dna will be made and it will show up on images
- match the bands from bottom up for known viruses and unknown pathogens
Antigen identification (ELISA test)
- antigens are unique molecules on cell’s surface and can be detected using antibodies (proteins that bind to specific antigen)
- antigens from pathogen = present if infected by it
- in ELISA = antibodies for the pathogen’s antigens are used as they have enzymes on them which react with substrate = colour change
- antibodies are added to sample tested and watched, but if bind to antigen, stay in sample so colour change when substrate is added = antigen (and so the pathogen) is present
What are the chemicals produced by plants and what do they do?
- citronella: insect repellents
- pine resin: insect repellents
- phenols: disrupts cell wall - anti bad compounds
- defensins: disrupts cell membrane - anti bac compounds
- pyrethrins: insecticide
- caffeine: toxic to fungi or insecticides - antifungal compounds
- chitinases: breaks down fungal call wall - antifungal compounds
How can you stop the spread of diseases in plants?
- biological control
- chemical control
- crop-rotation
- destroy infected plants
- no contact between infected and not infected plants
How can bacteria be spread?
- E. coli in unpasteurised milk
- Salmonella in unwashed vegetables
- Campylobacter in raw meat
What is a virus?
- attacks cells and replicates itself inside oranism
- burst and releases virus
- very small - 1/100th of a bac
- not cells
What is a fungi?
- single celled
- made of hypahe
- can penetrate skin or plant surface and cause diseases
- can produce spores to other animals and plants
Describe HPV?
- virus transmitted bodily fluids and sexually
- no symptoms mostly and clears in a few months
- BUT can cause cell changes resulting in certain types of cancer (thus cervical)
Describe HIV?
- enters lymph nodes and attack immune cells
- reproduces inside wbc and it can’t prevent infections and cancers
What are the adaptations of white blood cells?
- lymphocytes have a large nucleus to make antibodies
- phagocytes have a flexible loped nucleus so that they can move around and engulf germs
- both flexible so they can change their shape to pass out of capillaries
How does plant piece affect decomposition rates?
- large size
- low SA to volume ratio
- fewer microorganisms as they reproduce slower and so respire slower
Why is decomposition important for ecosystems?
- idea of recycling in nature
- named example of a recycled substance e.g.
carbon/nitrogen - example of reason why the recycling is important e.g. for photosynthesis / production of proteins in plants
What is an antibody?
- protein molecule made by the immune system
- destroys/kills pathogens / clumps them together / attaches to antigens
How does more mRNA mean more protein?
- mRNA carries the code for proteins
- more protein will be made
What is an antibiotic?
a chemical (usually) made by fungi / microbes (1) that kills (other) microbes / kills bacteria (1)
What elements do all proteins contain?
- C
- O
- N
- H
What type of characteristics would we genetic engineering plants to have?
- drought resistance
- disease resistance
- pest resistance
- herbicide resistance
- insect resistant
How can fertilisers help plants make proteins?
- plants make proteins using nitrogen from nitrates or nitrogen ions in fertilisers
What are the disadvantages of hydroponics?
- lots of fertilisers needed
- cost of setting up is high
- diseases can spread very quickly and cause major damage
What does a flushing agent do?
- used to help the blood sample flow from one end of the stick to the other through the paper strip
How do antigen tests work?
- antibodies complementary to the pathogen antigens are stuck to the point of the line
- if disease = pathogen antigens get bound to dye-labelled antibodies flow through start to end of strip
- pathogen antibody binds to the antibodies stuck on the line of the strip
- dye-labelled antibodies at strip create a visible coloured line
Why is high amounts of salt bad?
- increases blood pressure
- increases chance of heart disease and stroke
Why are stem cells used instead of foreign cells from donors?
- less chance of being rejected by the immune system as it has the same antigen
What virus can increase the chances of getting cervical cancer?
- HPV (not HIV)
Why are antibiotic-resistant markers used?
- to identify which bacteria have taken up the plasmid
Why did fossil fuel records show?
- a small change can result in larger changes
Why would minerals in the soil run out if there are no microorganisms in the soil?
- no microorganisms = no decomposers
- no decay happens
How can fungal infections spread?
- spread through fungal spores through the wind
- enter leaves through the stomata
- but if burn plants = kills spores so no infection can spread
How are antibodies made?
- antigens are detected
- triggers antibodies to be made by white blood cells
Why are placebos made?
- acts as a control
- can act as a comparison to check if the drug works
- identifying/eliminates any psychological effect
- placebo contains no active drug
What is a dominant allele?
- an allele is a form/version of a gene
- dominant means that it always expresses itself when
present
Why is informing people of their genetic disease good or bad?
- the person may decide not to have children
and therefore will not pass on the allele - there is a wide range of ages that a person of a
certain age can first show symptoms - it does not show how bad the symptoms are or
how long the person will live for - some people would rather not know when, or if,
they are likely to become ill - it’s useful to be aware and prepare for when
the first symptoms will show - less useful/reliable/predictable test of when the
first symptoms will show with a lower number
of CAG repeats. - less useful as there is no cure only limited
treatment for symptoms
Why will non-resistant alleles never die?
- Rr and Rr (heterozygous), would always make rr, a recessive allele, which may be not resistant
Why may people want to or not want to get tested for genetic diseases?
Ethical/moral/religious:
may or may not believe in testing
may or may not believe in terminations
may or may not be worried about discrimination against a
disabled child
may or may not believe there should be any interference in
nature (idea of playing God)
economic:
may or may not be able to afford care for child / treatment /
counselling (since medical services cost in some countries)
medical:
increased risk of miscarriage
risk to health of mother as a result of termination
risk to health of mother / fetus as a result of testing
false negative/positive test. Accuracy of the test.
plan for future medical treatment
circumstances:
may or may not have other healthy children to consider
may or may not have been trying for a baby for a long time
may or may not have had many miscarriages prior to this
baby
may or may not plan for the future
general:
can make decisions regarding termination
may, or may not, want to know whether the child has the
disease
couples will make different judgements about risks and
benefits of the test
idea that perception of risk is different to actual risk
the quality of life the child/parents will have
How can a gene determine the sex of a foetus?
- gene on Y chromosome forms testes
- absences of gene on Y chromosome form ovaries
What is a fair test?
- control all variables except the ones tested
- more confident in results
How are observation and prediction linked?
The observation increases the likelihood /
confidence in the prediction;
But does not necessarily prove it is correct;
How can a heart attack be caused?
What causes a heart attack:
- increased fatty deposits/blood clots/plaques/atheroma
- narrowing/blocking of arteries supplying the heart or coronary arteries
- less/no oxygen/glucose reaches the heart muscle
- cells in the heart die
Increased risk for Leo due to:
-poor diet / diet high in salt / diet high in fat/obesity
- stress
- smoking
- misuse of drugs
- less exercise
-high blood pressure
-drinking alcohol
- diabetes
What does sustainability mean?
meeting the needs of the people today (1)
without damaging the Earth for future generations (1
Explain why the carbon cycle is or is not an enclosed system?
For -
Carbon not (shown) entering / leaving the system;
Energy is not (shown) entering or leaving the system;
Idea of recycled / no waste;
Against -
Fossil fuels lock carbon away for a long time;
Carbon entering the atmosphere faster than leaving it;
Fossil fuels used up faster than replaced;
Sunlight / energy entering or leaving system;
How would scientists use genetic engineering to modify bacteria to make insulin and identify the successful ones?
Gene from a human
- Isolate / remove / cut out gene
- Use of enzymes
- Replicate gene
- (Put gene into) vector / virus / plasmid
INSERTION into bacteria may include:
- (DNA) incorporated into bacteria
- Replication of bacteria
- (Bacteria start) producing insulin
SELECTING bacteria include: Either with a fluorescent marker - Production of gene probe - Addition of probe to DNA - Probe attaches to correct gene - Probe fluoresces under UV Or with antibiotic resistant gene - Antibiotic resistant gene attached to insulin - Both genes taken up by bacteria - Bacteria treated with antibiotic - Bacteria with resistant gene and insulin gene survive / others do not
How does artificial cloning work for animals?
transfer nucleus from (adult) body cell into (unfertilised)
egg cell (1)
idea that egg cell is empty / had its own nucleus removed
(1)
How is nitrogen removed from an ecosystem?
rabbit/animal leaves/removed/migrates; (1)
(nitrogen compounds/soil) maybe washed away; (1)
(crop) plants/timber may be harvested/taken away; (1)
What causes cancer?
changes to DNA/genes
uncontrollable cell division/ rapidly dividing cells/ cell
divides many times by mitosis
creates a tumour
How would you genetically engineer mosquitos?
isolate the gene replicate/copy the gene use of a vector/plasmid to insert the gene into (mosquito) cells select the modified cells
How are antigens destroyed by our body?
(antigens trigger) white blood cells release antibodies /
antitoxins (1)
antibodies / antitoxins lock on to antigens (and destroy
them) (1)
white blood cells engulf antigens (1)
How does cloning occur?
nucleus removed from an egg cell/enucleated egg
(ignore DNA / genetic material)
nucleus from the udder / body cell is inserted into the
egg cell
BUT
egg cell nucleus replaced with the nucleus from an
udder / body cell (covers the first 2 indicative scientific
points)
(allow a correct example of a named body cell, ignore
unqualified cell eg adult cell)
(egg cell) given an electric shock to make it divide /
multiply (ignore just grow)
embryo /Dolly is genetically identical to / a clone of the
sheep from which the udder/body cell came from
or udder/body cell taken from the sheep they want to
clone
Genetic engineering meaning:
- a process which involves modifying the genome of an organism to introduce desirable characteristics
What is a chromosome?
Strand of DNA containing genes
What are the indicator species for pollution?
Unpolluted - mayfly larvae
Low pollution - freshwater Shrimp
High pollution - water louse
Very high pollution - sludge worm
