MOCKS Flashcards
size of a eukaryotic cell
10-100 um
size of a prokaryotic cell
0.1 - 5 um
what is the magnification and resolution of a light microscope
magnification: x 2000
resolution: x 200 nm
what is the magnification of an electron microscope
x 2,000,000
what is the resolution of a transmission and scanning microscope
transmission: 0.2nm
scanning: 10nm
size of image =
magnification * size of object
what two ways can you grow microorganisms in the lab
nutrient broth solution, agar jelly
why is the petri dish stored upside down
yo prevent condensation from the lid landing on the agar surface and disrupting growth
what are enzymes
biological catalysts that can break large molecules and join small ones
when an enzyme and substrate bond what do they form
an enzyme substrate complex
what two tests can you perform to test for lipids and what are the results if it is positive
Emulsion test - cloudy layer if lipid is present when ethanol is added
Sudan III test - red layer forms on top
rate =
change/time
RP: DESCRIBE THE EFFECT OF pH ON AN ENZYME
- drop of iodine is put into each well in a spotting tile
- using a water bath, warm a solution of amylase, starch and a buffer solution (independent variable)
- at regular intervals (10 secs) take drops of the solution and place in wells
- the starch is no longer present when idodine solution remains brown
- record the time it took for this to occur
- calculate the rate: 1000/time
the experiment should er repeated at different pH values.
advantage of using stents
effective in lowering the risk of a heart attavk, fast recovery time
disadvantages of using stents
thrombosis (blood clots) can form, infection or heart attacks could occur during surgery
what do statins do
they are drugs which reduce the level of bad cholesterol in out body (help with CHD)
advantages of using statins
reduce the risk of stroke, CHD and heart attacks, increase the level lf good cholesterol
disadvantages of using statins
can have side effects , may not hace an immediate effect, has to be taken continuously
biological valves can be used to fix faulty valves. name one advantage and one disadvantage
adv: works very well
dis: lasts only 12-15yrs
mechanical valves can be used to fix faulty valves. state one advantage and one disadvantage
adv: lasts a long time
dis: needs a lot of medication
state the advantages of using an artificial heart
less likely to be rejected as it isn’t recognised as foreign
state the disadvantages of using an artificial heart
temporarily leaves the body exposed to infection, blood clots can form, motor can fail and the mechanical parts wear out, drugs are taken to thin the patients blood (infects the individual’s bleeding if they are hurt)
if there is extreme blood loss how can it be solved.
by using artificial blood (salt solution)
state an advantage and disadvantage of using artificial blood
adv: has more time to produce new cells
dis: can only be used for short periods of time then a blood transfusion has to take place
how does smoking and alcohol consumption affect pregnancy
reduces the amount of oxygen transported - can have effects on the development of the brain in the foetus
what does exposure to carcinogens affect
cancer
how are communicable diseases spread
direct contact, airborne organisms, indirect contac, contaminated food and drink
how can transmission of communicable diseases be prevented by
improving hygiene, reducing contact with infected individuals, removing vectors, vaccination
how are measles spread and how can it be prevented
spread via droplet infection and can be prevented via vaccination
how is TMV spread and how can it prevented. what are the symptoms
discolouration of leaves. spread via contact-insects act as vectors. prevented by growing TMV resistant strains and good field hygiene and pest control
how does bacteria damage cells
produce toxins
what type of disease is gonorrhoea
bacterial disease
how is gonorrhoea spread and how can it be prevented
spread through unprotected sexual contact and to prevent it you can use contraception and antibiotic.
how can crown galls be prevented
scientists add new genes to the bacteria
how is malaria spread and how can it be prevented
spread via vectors (female mosquito) where the protists reproduce sexual lay. the protists enter human blood stream via the mosquito’s saliva and then they enter RBC and damage them
describe the production of monoclonal antibodies
- mouse lymphocytes are stimulated to produce a particular antibody
- lymphocytes are extracted abd combined with tumor cells to make a hybridoma cell
- hybridoma cells are cloned to produce lots of identical copies
- the antibodies are collected and purified
how do pregnancy tests work
the monoclonal antibodies are specific to the hCG hormone which is present in women’s urine during pregnancy. they will bind to the hormone if present and produce a blue line.
monoclonal antibodies can be used in laboratories to…
measure and monitor the levels of hormones or chemicals in the blood
monoclonal bodies can be used to prevent cancer by blocking…
the receptor site which stops them growing and dividing
what 3 things in our body is energy needed for
- maintain body temperature
- muscular contraction
- build large molecules from smaller ones
nervous and hormonal communication is involved in the
automatic control systems
describe the pathway when there is a change in the environment
- the receptor cells convert the stimulus into an electrical impulse
- the electrical impulse travels along cells called a sensory neurone to the CNS
- Information is processed and the appropriate response is coordinated
- the electrical impulse is sent along the motor neurones to effectors
-the effectors carry out the response
what is the pathway for a reflex arc
- a stimulus is detected by receptors
- impulses are sent along a sensory neurone
- in the CNS the impulse passed to a relay neuron
-impulses are sent along a motor neurone - impulse reaches an effector resulting in the appropriate response
what is the role of DNA
contains instructions for building an organism and instructions to instruct cells to make proteins
what are nucleotides
things which make up DNA. they are made up of one sugar molecule, a phosphate molecule and one of the four types of organic bases
what does coding DNA determine
the proteins and their activity
name the two types of proteins and give an example
structural (muscles)
functional (enzymes)
what is gene expression
a gene is expressed when it is used to make a protein
what is transcription
taking a single gene and copying it to mRNA. it takes place inside the nucleus
what is translation
taking the mRNA and making a protein
describe the process of protein synthesis
transcription:
- DNA contains the genetic code for making a protein but it cannot move out of the nucleus as it is too big
- the DNA unzips (two strands pull apart from each other) and the mRNA nucleotides match their complementary base on the strand
- the mRNA nucleotides then join together to create a new strand (mRNA strand). this strand is a template of the original DNA
translation:
- mRNA moves out of the nucleus to the cytoplasm and onto the ribosomes
- the correct sequence of amino acids are brought to the ribosomes by carrier molecules. the bases on the mRNA are read in threes
- the amino acids connect together to form a protein
how is biomass produced
photosynthetic organisms
biogas generators produce what
Methane gas
disadvantages of producing methane gas in biogas generators
constant temperature is required and it cannot be stored as a liquid therefore must be used immediately
what factors affect food security
- increasing birthrate and decreasing death rate
- new pests and pathogens
- climate change and natural disasters
- war and conflict, cost of agricultural inputs
- changing diets (increased demand of specific food)
what is peat
a material that forms when plant material hasn’t fully decayed due to a lack of oxygen
what do we use peat for
fuel
describe the field investigation tes5
- put 30m tape measure from the base of a tree to an open area of ground
- put the Quadrat against the transect line. one corner of the quadrat should touch the 0m mark
- count the number of plants inside the quadrat
- use the light meter to measure the light intensity at that point
- ## move the quadrat 5m up every6tine and repeat
describe the decay practical
- half fill 250cm^3 beaker with water from. the kettle this will be the water bath
- label two test tubes. one lipase and one milk
- in the lipase test tube put 1cm^3 of lipase solution
- in the milk test tube put 5 drops of Cresol red solution, 5cm^3 milk and 7cm^3 sodium carbonate in this order. the solution should now be purple
- put both test tubes into the water bath and wait until they reach the same temperature as the water bath (use a thermometer)
- transfer the content of the lipase test tube to the milk one and start the stopwatch
- stir the contents and time how long it takes to turn yellow
- repeat with different temperatures
