biodiversity and natural resources Flashcards
what is the definition of endemic?
only found in one geographical location
what effect does successfully interbreeding have on genetic diversity?
- increases
- because of introduction of new alleles into the population
what is the definition of an allele?
different form of a gene
what information is needed to compare the biodiversities of 2 woodlands?
- biodiversity measured using a diversity index
- species richness
- genetic diversity of populations
- presence of any endemic species
what aseptic techniques should be used when working safely with bacteria?
- flaming instruments
- keeping lids off for minimum time
*sterilising work surfaces - working near a bunsen burner
why can some bacteria grow rapidly in skin wounds?
- warm temperature increases rate of reactions in bacteria
*availability of energy source from tissue/ blood - availability of water for bacterial cell funtions
- good oxygen availability for aerobic respiration
how do breeding programmes in zoos maintain genetic diversity of captive populations?
- animals selected to prevent breeding between closely related individuals
- a stud book is used to select individuals for mating
*exchange of animals between zoos
why are healthy volunteers given different doses of the drug or a placebo?
- check for side effects
- different doses to determine safe dose
- placebo to make sure any side effects were due to drug
how would clinical trials of a vaccine be conducted?
*healthy volunteers given vaccine to test for side effects
*tested for presence of antibodies to the virus
*patients given the vaccine
*number of people who develop the virus after vaccination are monitored
what are suitable conditions for keeping seeds in a seed bank?
cold, dry
what role does a placebo have in producing valid conclusions?
- provides a control group for comparison
*ensuring that drug is causing the effect
what role does a double blind trial have in producing valid conclusions?
- neither doctors nor patients know who has been given the acc drug
*ensures bias has been removed from the trial
compare and contrast modern drug testing with William witherings method
- both use diff doses to determine safe dose
- William did not use healthy volunteers
*William did not use a placebo
what is the relationship between the structure and functions of a grana in photosynthesis?
- grana formed from many layers of thylakoid membrane to increase sa
- thylakoid membranes contain chlorophyll to absorb light
- electron carrier molecules in thylakoid membrane involved in ATP production
what monomer makes up cellulose?
beta glucose
compare and contrast the structure of cellulose and amylopectin
- both polymers of glucose
*both have 1,4 glycosidic bonds
*cellulose beta glucose, amylopectin alpha
*cellulose not branched, amylopectin is
what properties can lignin give to cell walls?
strength and waterproofing
what is the role of the middle lamella when a plant cell completes mitosis?
- produced between adjacent new cell
- because middle lamella holds cell walls together
what are the effects of a shortage of Mg+ on a plant?
- limits production of chlorophyll
- lack of glucose due to less photosynthesis
- leaves may be yellow/ stunted growth
why does a sieve tube element not require RER and ribosomes?
- no transcription so no ribosomes needed for translation
- no proteins synthesised to be processed in RER
what is the structure of starch?
- polysaccharide made from alpha glucose
- monomers in the chains joined by 1,4 glycosidic links
- contains amylose and amylopectin
*branches joined to chains by 1,6 glycosidic links
why must starch be broken down before it can be used by cells of a growing plant?
- produce glucose
- which is used in respiration
what is the difference in number of mitochondria in sieve tube elements and companion cell?
- CC has more
- role of ST is to provide channel so cellular contents are kept to a minimum
*ST has limited ability to carry out aerobic respiration
*ATP supplied to ST from CC
what is meant by the term tensile strength?
the pulling force a fibre can withstand before breaking
why are captive breeding programmes important for maintaining biodiversity?
- increase population size of species
- increase genetic diversity
- prevents extinction
justify continued funding of seed banks
conserves genetic diversity of crops
crops protected from natural disasters
crops kept may have traits useful in future eg disease resistance
helps ensure future food security
what is meant by species richness?
measures number of species in a habitat
what is meant by heterozygosity index?
a measure of genetic diversity within a population
OR
proportion of heterozygous individuals in a population
explain how would the index of diversity change if herbicides were sprayed on a lawn?
decrease
fewer species present
explain why captive breeding programmes are important for maintaining biodiversity
increases population size of species
maintains/ increases genetic diversity
therefore prevents extinction of species
give 2 reasons why snow leopard cubs born in captivity have not been released into the wild
needed for captive breeding programme
would be at risk if released
not prepared for reintroduction
explain why the agar plate was incubated at 25ºC
to allow bac to multiply
without encouraging pathogenic organisms
explain the advantages of drying seeds before storage
extends storage time of the seeds
because drying prevents germination/ decomposition
justify the benefits of storing seeds
prevent species from becoming extinct
safeguarding genes that may prove useful in the future
allow for reintroduction of species
explain why bacteria are able to multiply in the bloodstream when they enter the body
warm conditions/ water/ glucose/ amino acids/ ideal pH available
suitable temp/ pH for bacterial enzymes
glucose used for respiration/ energy
amino acids used for growth
explain why the use of bamboo fibres to make coffee cups is sustainable
available to future gens
renewable resource
more bamboo plants can be grown
Plant-based products provide a sustainable alternative to oil-based plastics. The tensile strength of plant fibres can be tested using different methods.
One method is to attach both ends of a fibre to clamps horizontally and hang increasing numbers of masses until the fibre breaks.
A second method is to attach one end of a fibre to a clamp and the other to a forcemeter, pulling on the forcemeter until the fibre breaks.
Explain which method will give more accurate results.
second because exact value will be shown on forecemeter
first is less accurate cos true value will be between 2 masses
which variables need to be controlled when testing the tensile strength of fibres
temp
humidity
describe how tensile strength of fibres can be measured
tensile strength calculates as a factor of force divided by cross sectional area of fibre
add force/ weight/ mass to a fibre
measure force/ weight/ mass required to break fibre
calculation of cross sectional area
explain how the structure and properties of starch are related to its function as a storage molecule
contains glucose needed for respiration/ energy
insoluble so has no osmotic effect
amylose is coiled making starch compact
amylopectin is branched so is rapidly hydrolysed
describe the positions in the stem of the tissues that contain lignin
sclerenchyma fibres on the outer side of the vascular bundle
xylem vessels on the inside
describe the importance of magnesium ions in the production of plant fibres
magnesium is essential to produce chlorophyll
chlorophyll is necessary to produce glucose during photosynthesis
glucose needed to produce cellulose for the cell walls
describe the arrangement of glucose monomers in a cellulose molecule
1,4 glycosidic bonds
alternative monomers inverted
explain why they are now classed as diff species
no longer able to interbreed to produce fertile offspring
because pops have become reproductively isolated
to which group do fungi belong
eukaryota
describe how the hardy- Weinberg equation can be used to provide evidence for changes in a population
calc allele frequencies
regular sampling over a period of time
explain how molecular phylogeny can be used to show that 2 pops are reproductively isolated
compare similarities/ diffs in DNA/ proteins
compare amino acid sequences
more diffs, more likely they are to be reproductively isolated
