Topic 4- Biodiversity and Plant Resources Flashcards
What do we assume when using the Hardy weinberg principle?
- has to be a large population with no immigration, emigration, mutations or natural selection
- random mating so all possible genotypes can breed with others
What does Hardy Weinberg principle predict?
- frequencies of alleles in a population won’t change from one generation to the next
- if allele frequencies do change = immigration, emigration, natural selection or mutations have occured
What is molecular phylogeny?
- phylogeny= study of the evolutionary history of groups of organisms
- molecular phylogeny= looks at molecules like DNA and proteins to see how closely related organisms are
Describe the 3 Domain system against the 5 kingdom system.
- prokaryotae (unicellular organisms w/out a nucleus) split into 2 groups
- archaea and bacteria because molecular phylogeny found that they were more distantly related than thought
- 4 other kingdoms are part of eukaryota domain
What are the 5 kingdoms?
- animalia
- plantae
- prokaryotae
- fungi
- protoctista
Define conservation
involves the protection and management of endangered species
e.g seed banks and zoos conserve endangered species and genetic diversity
What are the advantages of seed banks?
- cheaper to store seeds than fully grown plants
- take up less space
- less labour required to look after plants
What are the disadvantages to seed banks?
- testing for viability is expensive and time consuming
- may be expensive to store all types of plant AND test them
- can be difficult to collect plants from remote locations
What re the 4 things zoos do to conserve species?
- captive breeding programmes= increase no. individuals while maintaining genetic diversity
- scientific research= inform conservation inside zoos
- reintroduction programmes= prevent species going extinct in the wild will also help other species (for food and habitat)
- education programmes= raise funds for conservation + change human behaviour
What are zoo advantages and disadvantages?
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- scientists can study behaviours closely to aid conservation that may not have been possible in the wild
- educate public about conservation
- increase population numbers
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- studies may not be reliable as animals act differently in captivity
- certain animals may not breed in captivity
- zoos may not provide adequate habitats
What is the middle lamella?
- outermost layer of plant celll
- acts as an adhesive to stick to adjacent plant cells = provide plant w/ stability
What is the plasmodesmata?
- channels in cell walls that link adjacent cells together
- allows transport of substances between cells
What are pits?
- regions of cell wall where very thin and arranges in pairs with adjacent cell pits
- allows transport of substances between cells
What is an amyloplast?
- organelle enclosed by a membrane containing starch granules
- convert starch into glucose when plant requires it
What is the vacuole?
- compartment surrounded by a membrane called the tonoplast
- vacuole contains cell sap to keep cell turgid (stop wilting)
- cell sap is made up of enzymes, water, minerals and waste products = involved in breakdown of unwanted chemicals
- tonoplast controls what enters/leaves vacuole
Describe xylem vessels (5)
- function is to transport water and mineral ions up plant + provide support
- long, tube like made from dead cells joined end to end (found in bundles)
- cells have hollow lumen with no end walls = allows water + mineral ions to pass up tube easily
- walls thickened w/ lignin (woody substance)= support plant
- water + mineral ions move in/out of vessels via pits where there is no lignin
Describe Phloem tissue (5)
- function is to transport organic solutes (sucrose) from where they’re made in plant to where needed = translocation
- cellls arranged in tubes but just for transport (not support)
- contain sieve cells and companion cells (one companion cell for every sieve tube element to carry out functions for them as sieve tubes have very few organelles and no nucleus)
- sieve tube elements have end walls with lots of holes for solutes to pass through
- made of living cells
Describe sclerenchyma fibres (5)
- provide support
- made of bundles of dead cells running vertically up stem
- hollow lumen with end walls
- cell walls thickened w/ lignin and have more cellulose than other plant cells
- no pits
Describe how you would prepare a plant stem for a microscope (4)
- use a scalpel to cut a cross section of the stem as thinly as possinle
- use tweezers to gently place section in water until use
- transfer each section to a dish containing toluidine blue stain and leave for 1 min (it will stain lignin blue/green and other tissube pinkish purple)
- rinse them w/ water and mount each onto a slide w/ cover slip
What is starch’s function and structure?
- storage of excess glucose in plants
- made up of two polysaccharides
- amylose= long unbrached chain/ 1,4 glycosidic bonds cause it to coil up/ compact and good for storage (more glucose in small space)
- amylopectin= long branched chain/1,4 and 1,6 glycosidic bonds/ side branches allow enzymes to break down molecule at glycosidic bonds quickly (glucose released quickly)
- starch is insoluble so doen’t cause cells to swell by osmosis (water entering)
What is cellulose and its function ?
- component of cell walls in plants
- made up of long unbranched chains of beta glucose (1,4 glycosidic bonds)/ the bonds are straight so molecule is straight
- 50-80 cellulose chains crosslinked by H bonds to form strong threads= myofibrils
- myofibrils provide structural support
- evry other monomer is inverted
What is water and mineral ions used for in plants?
- water= photosynthesis and to transport minerals/ regulate temp. / structural stability
- magnesium ions= involved in production of chlorophyll (pigment for photosynthesis)
- nitrate ions= involved in synthesis of DNA, proteins and chlorophyll
- calcium ions= important components of cell walls and for plant growth
What are some aseptic techniques? (4)
- close windows and doors to prevent draughts disturbing the air
- regularly disinfect surfaces to minimise contamination/ pututensils in disinfectant, not on surface
- sterile equiptment/ flame or use an autoclave (steams equiptment at high pressure)
- work near a bunden flame when transferring bacteria (hot air rises and any microbes will be drawn away from agar)
describe William Withering’s digitalis soup
- discovered extract from foxgloves could treat dropsy (contains active drug digitalis)
- by chance he found one patient recovered from a traditional remedy containing foxgloves
- foxgloves are poisonous so he tested different versions w/ diff conc. on patients
- found too much poisoned, while too little had no effect
- to find out right dosage to give to patient
Describe the different phases in modern drug testing
Pre clinical tests- drug is tested on human tissues, then animals
Phase 1- test new drug on healthy individuals to find correct dosage, how body reacts and side effects?
Phase 2- larger group of patients who require drug/ effectiveness?
- patients are split into 2 groups, one w/ placebo and one w/ drug (does drug work more than placebo effect?)
Phase 3- large group split into 2, one w/ existing drug and one w/ new drug
- does it work better than the existing drug?
What is the gene pool?
- the no. different alles in a population
What does inbreeding cause?
- decreases gene pool which leads to increased risk of genetic disorders, leading to health problems
Define genetic drift
- random change in frequency of alleles
- affects smaller populations mmore because smaller gene pools
What are the ways in which organisms adapt to a niche?
- behavioural= how an organisms acts to increase chance of survival (possums play dead)
- physiological= processes inside an organism’s body that increase chnace of survival (hibernation)
- anatomical= structural features on organism’s body that increase chnace of survival (blubber to keep warm)
Define species
- a group of organisms of the same type that are able to reproduce with eachother to produce fertile offspring
What is species evenness?
- if good evennes means that most species in a community are of similar abundance
- no single species dominates
What is genetic diversity?
- variation of alles w/in a species population to allow for an advantage if a disease affects one allele
What is habitat diversity?
- no. different habitats in an area due to abiotic and biotic factors
What information needs to be collected when studying biodiversity of areas?
- genetic diversity using heterozygosity index
- biodiversity with diversity index
- are there endemic species present
- species richness by counting how many species are present in an area
Why are plant fibres more sustainable than fibres made from crude oil?
- crude oil is non renewable and finite resource because it takes millions of years to form
- nettles are renewable because they can be grwon in a short amount of time
- clothing made of nettles is biodegradable
