wrong answers Flashcards
what is the equation of waist to hip ratio
waist measurement/hip measurement in meters
how does cancer develop in the liver
cell division becomes uncontrolled which will lead to the formations of a tumour
what does a high BMI but average waist to hip ratio show
.the person is overweight but their hip to waist ratio shows he is not abdominally obese
.his weight is evenly distributed over the body and not around the vital organs
obesity is linked with the development of cancer
the fat tissue send signals that cause cell division
how could this lead to cancer?
.When cells are triggered to divide by mitosis, this division can become uncontrolled
.it will eventually create a tumour
during which cell cycle is DNA replicated
interphase
how are people with chlamydia more likely to be infected with both chlamydia and gonorrhoea
.both are STI’s spread through the same mechanisms
.catching either one of the infection shows that the individual does not use barrier contraception methods making them more likely to catch Gonorrhoea
what part of the blood transports insulin to its target organs
plasma
how is adrenalin transported from the adrenal glands to its target organs
it is dissolved in blood plasma
explain why shivering helps humans to regulate body temperature
.stops body temperature falling
.increases muscle contractions
.generates heat via respiration
why do igunas pant when their hot
.panting causes water loss
.causing evaporation, removal in heat
.and reduction in temperature
explain why sweating helps cool the body
two bullets
.sweat in released on the skin
.it evaporates and transfers thermal energy out the body
how does the kangaroo rat flited excess sodium ions and water
.liquid part of the blood goes through the Bowmans capsule where the useful substances are reabsorbed
.excess fluid and sodium irons are removed
how does sewage pollution in the river decrease the oxygen levels in water
. increases levels of aerobic bacteria
.kill plants as it prevents them from getting light and photosynthesising
explain why compost bins have gaps at the sides
.to drain out water
.to allow oxygen to enter
why is water treated with chemicals
.to destroy pathogens
explain why nitrate levels in soil improve crop yield
. nitrites are needed to make protein that’s needed for growth
why is soil added to the compost bin and it is turned to add air
.to introduce microorganisms and decomposers
.to add oxygen
difference between mitosis and meiosis
.mitosis produces 2 identical diploid cells
.miosis produced 4 genetically diffrent haploid cells that become sex cells/gamete
.motisis produces body cells
explain the stages of mitosis
prophase: DNA unwinds and condenses into chromosomes and the nuclear membrane disappears
metaphase: chromosomes line up along the centre of the cell
Anaphase: chromatids are pulled to the edges of the cell by the spindle fibres
Telophase: a nuclear membrane form around each of the sets of chromosomes separating them from one another
cytokinesis occurs splitting the cytoplasm to create two separate daughter cells
function of the meristem
3 bullets
.collectionsof undifferentiated cells that can become specialised and elongate
.divide to produce more cells through mitosis
.allows plants to grow and repair
why would the use of adult stem instead of embryonic stem cells help
.less of an ethical dilemma
.have the potential to produce any cell type
.more availability
.less possibility of rejection
why are percentile charts used
.to monitor growth
.to compare the grow of an individual to the standard growth pattern
state the effect of cancer on cell division
causes uncontrolled division of cells
describe the theory of evolution by natural selection
.organisms within species mutate
.there is a struggle to survive due to competition or change in environment
.the well adapted organisms survive
.they live long enough to produce offspring that inherit the favoured characteristic
.this is repeated over many generations
name one method that can be used to date a fossil
radiometric dating
what is the function of the reflex arc
.to respond to danger
.it goes to the spinal chord without thinking so there is a faster unconscious response to protect the body from harm
explain how a persons reaction time is affected by alcohol
.alcohol delays a persons reaction time
.reducing transition across the synapses
how do painkillers reduce pain
. prevent neurotransmitters from binding to receptors in the next neuron
. the electrical impulse isn’t triggered and the signal is not received by the central nerves system so the person does not feel pain
how are signals transmitted across a synapse
.the synapse is a gap between 2 neurones
.it triggers the release of neurotransmitters which diffuse across the gap as a chemical signal
.neurotransmitters bind to receptor on the next neurone
explain why the cytoplasm shrinks away from the sides of the cell when the plant cell is in salt water
.the water moves out of the cell by osmosis
what is an autoclave
.a sterilisation machine that works by superheating steam
how would you tests for starch
.use iodine solution which is naturally orange yellow
.add to the food solution
.solution will turn blue/black in the presence of starch
what happens during cell interphase
.the DNA replicates
.chromosomes coil up/condense
what are the two lenses found on a microscope
.objective lens
.eyepiece lens (10x)
how does genetic analysis provide evidence for evolution
.can compare the gene sequences from different organisms
.closely related organisms have more similar sequences
.this can show evolution be finding common ancestors
why can antibiotics treat bacterial infections in humans
.prevents bacteria from reproducing or destroys them
.does affect human cells
.prevents bacteria protein synthesis
what is a genotype
the collection of gene an organisim has
two ways in which communicable diseases are different to non-communicable
.caused by pathogens
.are passed from one person to another
.communicable cannot be inherited
.
precautions to prevent contamination of the agar jelly plate
.wearing gloves and mask
.use sterilized equipment
.work near a Bunsen burner
what happens during prophase
.chromatids/chromosomes condense
.chromosomes join up
.the nucleic membrane breaks down
pros and cons of using stem cell therapy to treat arthritis
pros: stem cells differentiate into specialised cells, they can replace the damaged/destroyed cells
.improve patients quality of life
cons: the stem cells may not function correctly
.cells may be rejected
.stem cells could continue to divide (cancer)
safety precautions when removing blood
.cover wound
.sterilize equipment
.wear gloves
why does the time taken for milk to curdle decrease as the temperature increases from 30c to 40c
.40c is/is closer to the optimum temperature for the enzyme to function
.as temperature increases, the kinetic energy increases, the increases the likelihood of collisions
.this allows more enzyme-substrate complexes to be formed
how to genetically modify a bacterial cell to produce chymosin
.plasmid is removed from bacteria and cut with restriction enzymes
.chymosin gene is cut with restriction enzymes
.sticky ends are complementary
.ligase is used to connect the chymosin gene and the plasmid
.the plasmid with the chymosin gene is then reinserted into the bacteria.
how do bacteria develop antibiotic resistance
bacteria reproduce rapidly generating a large
population
* there is variation among a bacterial population
* some bacteria develop a resistance to antibiotics
through mutation
* antibiotic treatment exerts a selection pressure
* bacteria resistant to antibiotics survive
* antibiotic resistance inherited
* non-resistant bacteria do not survive
* levels of antibiotic resistance in a population of
bacteria increase
how are monoclonal antibodies made and used to detect STDs from urine samples
- isolate an antigen from the pathogen which causes the
STI - inject the antigen into a mouse/rodent
- collect lymphocytes producing an antibody to the STI
antigen - fuse the B-lymphocyte with a myeloma cell
- production of a hybridoma
- hybridoma produces a monoclonal antibody against the
antigen of the STI - attach the monoclonal antibody to coloured bead/indicator
- incorporate into a test strip.
how can draught resistant plants be produced
- genetic variation means that some plants will be tolerant
of drought conditions and these can be selected (1) - cross-pollinate these plants and grow the seeds under
drought conditions (1) - select offspring and repeat over several generations (1)
devise a plan to test the effectiveness of a new diet to help treat obesity with 40 fat people
.weigh the 40 people
.place half of them on the new diet and keep half on their regular diet
.after a substantial amount of time re-weigh the 4o people and compare results
how did Mendel use homozygous tall and homozygous short pea plants to determine that the tall allele is dominant to the short allele
.cross bred the two pea plants together to produce tall offspring
.though their phenotype was to be tall pea plants, the offspring were heterozygous possessing both the tall and short allele
.but the tall allele is dominate and so contributes to the plants physical characteristic
why is seed production and advantage to strawberry plants
introduces variation into the population allowing for natural selection (survival of the fittest), increasing the species likelihood of survival
what are variables that should be controlled when carrying out the osmosis practical with potato cubes in different salt solution concentrations (3)
.type of the potatoes
.age of the potatoes
.temperature
why must the potato be dried in the osmosis experiment
to get a more accurate reading
what does it mean when there is no mass at a specific salt solution concentration
how is this shown on the graph
the isotonic salt concentration has been reached
there is no net movement of water/no salt
concentration gradient
what is the equation for actual image
image size/magnification
what type of neurone is the optic nerve
relay neurone
what region of the CNS is responsible for vision
cerebrum
why can enzymes only catalyse specific reactions
.active site of the enzyme has a specific shape because of the order of amino acids
.the substrate must have a complementary shape to the active site in order for the enzyme to work
explain the effect of penicillin on bacterial and human cells
.penicillin prevents the bacteria from dividing as they
cannot make a new cell wall (1)
* because humans cells do not have a cell wall (1)
* they are unaffected by penicillin (1)
how can scientists genetically modify bacterium to produce penicillin
- use restriction enzymes to remove the gene and cut the
plasmid (1) - use of ligase to join DNA molecules together (1)
- cut the gene from the genome of the fungus and
extract a plasmid from the bacteria (1) - insert the recombinant plasmid back into the bacteria
(1)
how do bacterium become antibiotic resistant
- bacteria reproduce rapidly generating a large
population - there is variation among a bacterial population
- some bacteria develop a resistance to antibiotics
through mutation - antibiotic treatment exerts a selection pressure
- bacteria resistant to antibiotics survive
- antibiotic resistance inherited
- non-resistant bacteria do not survive
- levels of antibiotic resistance in a population of
bacteria increase
how is the order of amino acids in protein determined by the sequence of the gene
- a single strand of messenger RNA is
transcribed from the gene in the
nucleus (1) - messenger RNA molecule binds to
the ribosome (1) - the triplet code from the mRNA is
matched by a complementary tRNA
anticodon at the ribosome (1) - tRNA transfers amino acids to the
polypeptide chain in a specific order
(1)
describe how the thinner beak of the goldfinch is a result of evolution
.a mutation occurs within the population of finches leading to some birds having thinner beaks
.this proves useful as selection pressures heighten the birds with variations likelihood to survive as thinner beak will allow them to reach more food
.finches with the mutation survive and reproduce passing the thin beak allele to their offspring
.this repeats over generations
how do the limbs of the five animals (all have pentadactyl limbs) show evidence for evolution
Presence of pentadactyl limbs show that some species evolved from a common ancestor that also had a pentadactyl limb and that individual bone structures have been adapted to different functions
describe the theory of evolution by natural selection
.there is an overpopulation of offspring
.organisms within a species have a mutation
.there is a struggle for survival due to selection pressures
.the adapted species survive and go one to reproduce passing on their allele
.this is repeated over many generations
explain how natural selection could have caused an increase in bird length due to the increased use of bird feeders
There is a mutation leading to some finches having longer beaks
The use of bird feeders act as selection pressures
Birds with longer beaks reach more food and so more of them live to adulthood and reproduce
The birds pass on their allele and over many generations the beak length of the bird population increases
how does scientists use gene sequencing of different animals as prof of evolution
.they compare gene sequences from different organisms
.closely related organisms have more similar sequences and diffrences in sequences can show evolution
how does a mutation in non-coding DNA prevent a gene being transcribed
mutations in non-coding effect how well RNA Polymerase binds
this means less coding DNA is transcribed and causes less mRNA to be produced
describe how light rays are focused to give normal vision
light rays are refracted by the lens (at the cornea) onto the retina
how is short sightedness corrected
.diverging/concaved lens
.the lens spreads out the light rays
three features of bacterial cells
.prokaryotic (no nucleus/ DNA in chromosomal loop)
.no membrane bound organelles
.flagellum
how does the eye change when going from looking at distant objects to near objects
the lens gets thicker to bend the light rays more
how does a gastric band help people loose weight
.reduces the volume of the stomach
.reducing food intake
.so stored fats will be used up
what happens when potato slices are put into salt water
.cells loose water/becomes plomolysed
.water moves out through osmosis
.from high water content graidient to low
precautions a doctor should take when treating infected patients
.sterilize equipment
.wear gloves and a mask
.wash hands
.get immunised
using adult stem cells
.no need to use embryonic cells
.used to cure diseases that are currently incurable
.less chance of rejection
pros and cons of producing painkillers from genetically modified yeast cells rather than extracting from poppies
.GM yeast can produce more ( higher yeild)
.yeast cells are not weather dependant
.painkillers made from yeast cells may be produced illegally
.we don’t know the long term health effects
how does an electron microscope help us to understand more about cillia cells
.higher resolution and so greater magnification
.so cillia is more visible
.sub-cellular structures are more visible
advantage of using electron microscopes to see plant cells
higher resolution and so greater magnification
.more detailed image
two explained ways to improve a microscope to get more detailed observations
.adjust focus of the microscope to see cells clearer
.use a stain to see sub-cellular parts better
.increase objective lens magnification to see more
why are electron microscopes good to see white blood cells
.greater resolution and therefor greater magnification
.smaller structures can be identified because of this
ways in which the WBCs protect against disease
.engulf pathogens via phagocytosis
.produce antibodies
.memory lymphocytes produce antibodies of known pathogens quickley
name one part of a light microscope that can be mo0ved to obtain a clear image of plant cells
focusing wheel
how can mutations effect the action of an enzyme
a mutation is the change in a base sequence of a gene
this change causes a change in the order of amino acids when making a protein
this then changes the shape of the active site of the enzyme produced
effecting how well the substrate binds to the enzyme
why can enzymes only catalyse specific reactions
.active site of an enzyme has a specific shape due to the order of amino acids
.the active site must have a complementary shape to the substrate in order to form complexes
what happens after a gene is transcribed but before translation
mRNA strand leaves the cell nucleus into the cytoplasm
through the cellular membrane
attaches itself to the ribosome
explain the lock and key
enzyme and substrate have complementary shapes
substrate fits into the enzyme to for an enzyme substrate complex
the enzyme causes a reaction changing the substrate
the product produced leaves the enzyme in order for it to be used again
why can outbreaks of whooping cough still occur is children can be vaccinated (4 possible answers)
.not enough people are immunised for herd immunity to work
.immigration introduces unvaccinated people into population
.immunisation sometimes is not fully effective
.immunisation effectiveness decreases with age
describe the response of the human body to immunisation
immunisation introduces antigen and causes a immune response
lymphocytes produce antibodies specific to the pathogen
production of memory lymphocytes
how can house flies infect people with dysentery
housefly is a vector
lands on contaminated faeces
transfers dysentery onto food
infected food in ingested
how do mosquitos spread malaria
they are vectors
carry protozoan
pierces/bites human skin
infecting human
how can change in body mass cause people to develop diabetes
increase in weight can cause people to become overweight
their body may not respond to insulin and so their blood glucose will be too high
how is the order of amino acids in a protein determined by the sequence of the gene
mRNA polymerase is transcribed from a gene
it travels out the nucleus and binds to the ribosomes
codons of the mRNA is matched by the tRNA anticodons
tRNA transfers amino acids to the polypeptide chain in a specific order to eventually produce a protein
how do increased insulin injection effect blood glucose concentrations
.more blood glucose in converted in glycogen stores in the liver
.person will has low blood glucose levels and become hypoglycaemic
how can type two diabetics regulate blood glucose levels
sports to reduce glucose levels
diet control levels of glucose intake
insulin medication convert glucose into glycogen
person B has a low red blood cell count, what effect will this have
lack of energy
shortness of breath
define fertilisation
the fusing of a sperm and egg cell, these gametes produce a diploid zygote
what is the function of the mitochondria
site for aerobic respiration using glucose and oxygen to produce energy
how can type 1 diabetes be controlled
insulin injections
low carbohydrate diet
increasing exercise
low blood glucose levels
role of the myelin sheath
insulates electrical impulses
speeds up impluses traveling along the axon
function of platelets
allow for clotting to stop bleeding
act as physical barrier to prevent pathogens in cuts
what region of the CNS is responsible for vision
cerebrum
what are some different treatments available for cardiovascular disease
.lifestyle changes including weight loss
.surgery to treat narrow or blocked arteries
.life long medication to prevent blood clots/reduce blood pressure/thin the blood
why do statins need to be life long medication
when treatment is stopped LDL cholesterol begins to increase again, increasing risk of heart disease
how do adults develop immunity when most scarlet fever cases develop in children
exposure to bacteria stimulates an immune response
B-lymphocytes produce antibodies specific to the bacteria antigen
memory lymphocytes are made in event of infection of the same pathogen in the future
why is the bacteria agar jelly plate incubated at 37 degrees
to provide optimal growth conditions
myxopyronin inhibits bacterial RNA polymerase
why does the antibiotic treat bacterial infections in humans
.antibiotics prevent bacteria from reproducing
.it doesn’t effect eukaryotic cells
.It prevents the production of RNA polymerase binding during transcription and therefore prevents proteins from being made
what are three reasons why people might not be immunised
already had measles
vaccine is not accessible in some places
concerns over side effects of immunisation
children are vaccinated, explain why they do not get tetanus if the bacteria enter enter the body
vaccine allows the to develop immunity to the disease as the vaccine contains dead or inactive antigen of the pathogen
memory lymphocytes trigger production of antibodies leading to a secondary response killing the bacteria faster
why is it good that garlic plants produce a natural antiseptic
prevents damage to the plant, as it kills pests or microorganisms that eat/attack it
how does exercise cause weight loss
increases aerobic respiration, which burns fat stores in order to produce energy therefore loose weight.
why do scientists work near Bunsen burners when testing zones on inhibition
to sterilize the loop/spreader to kill microorganisms that may contaminate the experiment
or
creates a convection current preventing m,icroorganisms in the air falling onto the agar plate
what are precautions when handling aids blood
clean spills
dispose of samples safely
dispose of samples
suggest how tools may have helped early humans to survive
hunting
making fires
skinning animals
building shelters
why is mitochondrial DNA used rather than nuclear DNA
-higher abundance/easier to extract
-more stable over time and therefore less susceptible for decay
-high mutation rate
-inheritance down female line
explain why fossil records are incomplete
not all fossils have been located
sometimes conditions are not correct for fossil formation
soft tissue does not form fossils
why is a high percentage of oxygen in the atmosphere needed for large land animals to evolve
larger animals carry out greater functions
more aerobic respiration is carried out
as more energy is needed
how do biologists validate evidence for the discovery of the Pompeii
.publishing evidence and results in scientific getting other scientists to review their experiment
.getting other scientists to recreate experiment
.taking samples
.attending scientific conferences
what is meant by speciation
formation of a new species due to geographical isolation, no longer able to breed with the original species
explain how evolution by natural selection brings about changes in a species
how is the retina transmitted to the brain
electrical impulses are transmitted via the optic nerve to the brain
how light rays focused to give normal vision
light rays are refracted by the lens in the cornea onto the focal point onto the retina
describe causes of both short and long sightedness
short sightedness- light rays are focused in front of the retina and the cornea refracts light rays too much, the cornea is too convex
long sightedness-light rays are focused behind the retina and the lens doesn’t refract light enough, the eyeball is too short
what lense corrects short-sightedness and how
diverging lens refracts light rays outwards
so that light rays meet on the retina focus on the retina
what happens when bright light is directed into the eye
the pupil contract/get smaller
Iris changes shape
light intensity is detected by the retina
give a method that can be used to date a fossil
location in the rock layer
how are thinner beaks in species A finches a result of evolution
individuals within the population develop a base sequence mutation that changes the shape of the beak, making the beak shorted
selection pressures such as food shortages means there is a fight to survive
the birds with this variation are more suited at catching food
the birds with thinner beaks get more food and are therefore more likely to survive
they reproduce and pass on their desirable allele that codes for a thinner beak
this occurs over many generations
describe natural selection
there is an over production of offspring
organisms within a population have mutations
there is a fight for survival due to selections pressures/environmental changes
the adapted organisms survive and go one to reproduce
they pass on their allele to their offspring
this repeats over many generations
why is the enzyme protease added to crushed peas in DNA extraction
.protease breaks down proteins
.in the membrane, this destroys enzymes that may break down DNA
what are 4 variables that the student should keep the same when comparing DNA produced from two different fruits
.mass of the fruits crushed
.temperature
.volume of detergent
.method of crushing the fruits
what are four benefits of discovering the sequence of bases for all plants and animals
identify useful genes
track evolution
understand genetic disease
discover new medicines/treatments
