Technology + Advances in biology- plants + genome (6) Flashcards
how are plants cloned
by VEGETATIVE PROPAGATION
A form of asexual reproduction in which new plants develop from meristematic regions, i.e. tissue that is totipotent/stem cells that divide to form more stem cells and then differentiate into different types of specialised cells.
(small cells with thin cell walls and no large central vacuole)
name the parts of the plant that are meristematic
APICAL BUDS : in the tips of roots and shoots
AXILLARY BUDS : in the angle between the leaves and stem
VASCULAR CAMBIUM : the tissue that forms xylem and phloem and lies between them in vascular bundles
give 5 examples of natural cloning in plants
- what do they produce*
- WHAT ARE THEY?!*
They are storage organs for vegetative propagation, which produces genetically identical offspring/clones.
BULBs- onions, garlic, tulip, daffodils
RHIZOME- ginger
RUNNER- strawberries
TUBER- potatoes
CORM- crocuses
how are natural clones in plants produced in horticulture
By taking cuttings that contain meristematic tissue by removing stems, roots or leaves from a parent plant with good/beneficial features that are worth propagating.
Grafting makes an individual from two different plants of the same family eg. TOMTATO.
what must happen (3) + what must be given (3) to produce natural clones when taking different cuttings
Stem cuttings must form adventitious roots
Root cuttings must form adventitious shoots
Leaf cuttings must form adventitious roots and adventitious shoots
Stem and leaf cuttings must be given enough water as they have no roots to absorb it
Light and temperature are reduced and humidity increased to prevent/reduce H2O loss- cuttings are placed in polyethene bags, fine mist sprayed on them, kept in shade etc.
what are adventitious roots
Roots that form on any structure other than the main root.
How are cuttings prepared for growinggggg
Sterilised- chlorine/bleach- to remove pathogens
Hormones-
auxins= cell elongation,
cytokinins= cell division (quantities are changed to influence root and shoot growth)
what are the 6 points that increase the success rate of most cuttings
> use a non-flowering stem; so that all plant resources are available for root growth instead of flowers
> make an oblique cut in the stem; to maximise surface area for root growth
> use hormone rooting powder; to increase rate of growth, and control where growth occurs
> reduce leaves from two to four; to minimise transpiration/water loss whilst maintaining photosynthesis
> keep cutting well watered; to reduce water stress
> cover the cutting with a plastic bag for a few days; to increase humidity to decrease the water potential gradient between the air and spongy mesophyll in order to decrease transpiration
why are cuttings useful for investigating the effect of growing conditions on plants
The clones/offspring are genetically identical, therefore any differences during growth are due to environmental factors.
what is the difference between genome sequencing and genetic engineering
GS: gives information about the location of genes and provides evidence for the evolutionary links between organisms.
GE: involves manipulation of naturally occuring processes and enzymes.
what is a genome
an organism’s complete set of DNA, including all of its genes
The human genome contains approx. 25,000 genes with 3 bn base pairs, present in 22 pairs of autosomes, 1 pair of heterosomes (XX/XY) and mitochondria
when are micropropagation and tissue culture used
Micropropagation is ARTIFICIALLY growing a cutting/tissue (tissue callus) on agar (sterile medium) then transferring it to soil.
Used for plants that don’t respond well to natural cloning
have been genetically modified
are rare
need to be grown in a pathogen-free environment
don’t produce many seeds
what are sustainable resources
Ones that can continuously be replenished i.e. not finite, and provides energy without decreasing its own supply.
what is SUSTAINABILITY
Meeting the needs of today without compromising the needs of the future generations, without harming other life forms and preserving biodiversity.
what is sustainable management
Making harvesting/consumption of natural resources as sustainable as possible by replenishing resources as fast as the rate at which they are being depleted.
how can forestry become sustainable
-Demand for timber must balance w/ regrowth of seedlings
- AFFORESTATION
- Clear Cutting; a section of mature forest is removed & a new forest of economically desirable trees are planted. When trees harvested, same species seedlings replanted. HOWEVER, often a single species, ecological damage.
- Selective Logging; trees are removed from mature forest based on height/girth/species and are felled individually. (directed to minimise surrounding damage). Ensures growth of young seedlings.
- Coppicing; harvesting wood for weaving/thatching/firewood etc. Trees are cut close to the ground, leaving stools that can regrow. Many stems regrow from each stool. If managed, supports a wide range if species.
- Strip Cutting; trees cut out in strips due to age, tf constant regeneration.
How have the GALAPAGOS ISLANDS been affected by human activity
- Number of inhabitants & tourists has increased rapidly.
- Non-native introduction of animals by humans = predation eg. goats eating plant life on some islands, dogs/cats/rats eating giant tortoises
- Introduction of non-native plants; they compete with native plants, dec. pop.s, eg. taller trees
how is human activity being limited on the Galapagos Islands
ERADICATION programmes of wild goats from smaller islands + wild dogs.
Uprooting + using chemical herbicides to control taller, non-native trees.
Number of visitors, given a set of rules, only brought by licensed guides.
how is human activity affecting the Lake District and Snowdonia National Parks
- Millions of visitors walk on the footpaths, leading to erosion, loss of soil from hillsides. Soil enters the lakes/waterways and disturbs pH of the water.
- People leave the footpaths and trample the sensitive vegetation. Paths are often eroded by the rain + walkers, increasing this problem.
what are the methods of control being used to conserve Antarctica against human activity
- ALL WASTE except sewage/food waste must be taken by ship to another country to prevent pollution. Sewage being TREATED before release,
- Ships using thick oil are BANNED to prevent oil spills,
- TOURIST RESTRICTIONS- only on land at certain locations for certain hours,
- Hunting/whaling BANNED to prevent wildlife pop.s deccreasing
which methods of control are being used against human activity in Snowdonia/ the Lake District
Conservation charities/ LD National Park Authority attempt regular repair/maintenance of paths, encourage regrowth of damaged vegetation. Educating walkers.
Snowdonia: dug drains next to paths to prevent flooding.
how is the DNA pattern transferred from gel electrophoresis to a more permanent copy
Southern Blotting.
- DNA bands are transferred onto a tough nylon/nitrocellulose blot = identical to gel becasue the pattern sticks to the blot, an alkali buffer is used to break H-bonds (heat woule melt gel) and separate strands
- Blot is heated in a sealed bag of radioactive DNA probe, which hybridises the DNA, i.e. binds to fragments only with complementary sequences, then cooled
- the blot is washed of probe + dried, autoradiographed to detect radioactivity- tf position of DNA of interest is deduced and can be isolated from gel + cloned
- the nylon membrane is overlayed with X-ray film to deduce radioactive fragments
what is the gel electrophoresis used for PROTEINS
Polyacrylamide Gel Electrophoresis (PAGE)
used to separate different sized proteins. The protein can be +vely or -vely charged and a chemical is used to denature all those that are +vely so the negatively charged ones move towards the anode. Stained creates bands.
name the components in gel electrophoresis
+ instructions/methods used in practical
- POWER SUPPLY
- (POSITIVE) ANODE (electrode)
- (NEGATIVE) CATHODE (electrode)
- GEL- AGAROSE or polyacrylamide, on glass plate
- BUFFER SOLUTION
- WELLS for DNA SAMPLE LOADING (dye added)
- Melt agarose gel
- Toothed comb at one end to make wells
- Let gel set, add buffer solution
- Add blue dye to each sample of DNA so it sinks into wells + so one knows when to stop current, add to wells
- Connect electrodes to the power supply
- When stopped, add DNA stain (Azure A), rinse with water
how else can DNA be labelled in southern blotting
Using fluorescent probes and detected by a laser + detector on the nylon membrane.
Only the DNA fragments that bound to the fluorescent probe show up on the film, leading to a DNA fingerprint.
what is the first method of DNA sequencing (before separation)
CHAIN TERMINATING SEQUENCING- sanger dideoxy method
- DNA is cut into manageable fragments + they are separated
- Each fragment is mixed with primer, DNA polymerase, excess of normal nucleotides, terminator nucleotides w/ fluorescent tags (dideoxynucleotides- each base has a different colour tag)
- Mixture placed in thermal cycler (similar to one for PCR)
- Each time a terminator base is incorporated instead of a normal nucleotide, synthesis of DNA is terminated i.e. no more bases can be added.
- MANY CYCLES LATER, every possible DNA chain is produced w/ reaction stopped at every base.
how is the DNA sequence read (after sequencing)
DNA fragments are separated according to length/mass through a minute capillary tube (SIMILAR TO GEL ELECTROPHORESIS with cathode/anode) SMALLEST FRAGMENTS GO THROUGH FIRST
The fluorescent markers are used to identify FINAL BASE on each fragment. Lasers detect different colours. ORDER of bases is COMPLEMENTARY sequence to original strand.
Area of overlap are found between each of the fragments, giving correct order for entire genome, using data output computer.
what are the uses of DNA Sequencing with animals
- Analysing the human genome- analyse/compare genomes of individuals to reveal patterns in DNA- diseases, implication for health management
- Analysing the genome of pathogens- better treatment eg. antibiotics against TB
- Identifying species (DNA barcoding)- produce a stock sequence for each species
- Finding evolutionary relationships- PHYLOGENY- the closer the DNA sequence between species, the more recent the common ancestor
what are the two data-based uses of DNA sequencing
- <u>BIOINFORMATICS</u>- development of methods/software tools for understanding biological data- combining biology/computer science/statistics/maths/engineering to analyse/interpret
- COMPUTATIONAL BIOLOGY- using data from bioinformatics to build theoretical models of biological systems- leading to synthetic biology
