Technology + Advances in biology- plants + genome (6)

Question 1

how are plants cloned

Answer 1

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)

Question 2

name the parts of the plant that are meristematic

Answer 2

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

Question 3

give 5 examples of natural cloning in plants

• • what do they produce*
• • WHAT ARE THEY?!*

Answer 3

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

Question 4

how are natural clones in plants produced in horticulture

Answer 4

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.

Question 5

what must happen (3) + what must be given (3) to produce natural clones when taking different cuttings

Answer 5

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.

Question 6

what are adventitious roots

Answer 6

Roots that form on any structure other than the main root.

Question 7

How are cuttings prepared for growinggggg

Answer 7

Sterilised- chlorine/bleach- to remove pathogens

Hormones-

auxins= cell elongation,

cytokinins= cell division (quantities are changed to influence root and shoot growth)

Question 8

what are the 6 points that increase the success rate of most cuttings

Answer 8

> 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

Question 9

why are cuttings useful for investigating the effect of growing conditions on plants

Answer 9

The clones/offspring are genetically identical, therefore any differences during growth are due to environmental factors.

Question 10

what is the difference between genome sequencing and genetic engineering

Answer 10

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.

Question 11

what is a genome

Answer 11

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

Question 12

when are micropropagation and tissue culture used

Answer 12

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

Question 13

what are sustainable resources

Answer 13

Ones that can continuously be replenished i.e. not finite, and provides energy without decreasing its own supply.

Question 14

what is SUSTAINABILITY

Answer 14

Meeting the needs of today without compromising the needs of the future generations, without harming other life forms and preserving biodiversity.

Question 15

what is sustainable management

Answer 15

Making harvesting/consumption of natural resources as sustainable as possible by replenishing resources as fast as the rate at which they are being depleted.

Question 16

how can forestry become sustainable

Answer 16

-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.

Question 17

How have the GALAPAGOS ISLANDS been affected by human activity

Answer 17

1. Number of inhabitants & tourists has increased rapidly.
2. Non-native introduction of animals by humans = predation eg. goats eating plant life on some islands, dogs/cats/rats eating giant tortoises
3. Introduction of non-native plants; they compete with native plants, dec. pop.s, eg. taller trees

Question 18

how is human activity being limited on the Galapagos Islands

Answer 18

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.

Question 19

how is human activity affecting the Lake District and Snowdonia National Parks

Answer 19

• 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.

Question 20

what are the methods of control being used to conserve Antarctica against human activity

Answer 20

1. ALL WASTE except sewage/food waste must be taken by ship to another country to prevent pollution. Sewage being TREATED before release,
2. Ships using thick oil are BANNED to prevent oil spills,
3. TOURIST RESTRICTIONS- only on land at certain locations for certain hours,
4. Hunting/whaling BANNED to prevent wildlife pop.s deccreasing

Question 21

which methods of control are being used against human activity in Snowdonia/ the Lake District

Answer 21

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.

Question 22

how is the DNA pattern transferred from gel electrophoresis to a more permanent copy

Answer 22

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

Question 23

what is the gel electrophoresis used for PROTEINS

Answer 23

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.

Question 24

name the components in gel electrophoresis

+ instructions/methods used in practical

Answer 24

1. POWER SUPPLY
2. (POSITIVE) ANODE (electrode)
3. (NEGATIVE) CATHODE (electrode)
4. GEL- AGAROSE or polyacrylamide, on glass plate
5. BUFFER SOLUTION
6. WELLS for DNA SAMPLE LOADING (dye added)
7. Melt agarose gel
8. Toothed comb at one end to make wells
9. Let gel set, add buffer solution
10. Add blue dye to each sample of DNA so it sinks into wells + so one knows when to stop current, add to wells
11. Connect electrodes to the power supply
12. When stopped, add DNA stain (Azure A), rinse with water

Question 25

how else can DNA be *labelled* in southern blotting

Answer 25

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_.

Question 26

what is the first method of _DNA sequencing_ (*before separation)*

Answer 26

**CHAIN TERMINATING SEQUENCING- *sanger dideoxy method*** 1. *DNA is cut into manageable fragments + they are separated* 2. *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)* 3. *Mixture placed in **thermal cycler** (similar to one for PCR)* 4. *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.* 5. *MANY CYCLES LATER, every possible DNA chain is produced w/ reaction stopped at every base.*

Question 27

how is the DNA sequence read (after sequencing)

Answer 27

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**.

Question 28

what are the uses of _DNA Sequencing_ with animals

Answer 28

1. Analysing the **human genome**- *analyse/compare genomes of individuals to reveal patterns in DNA- **diseases**, implication for **health management*** 2. Analysing the **genome of pathogens**- better **treatment** eg. antibiotics against TB 3. **Identifying species** (DNA barcoding)- produce a **stock sequence** for each species 4. Finding **evolutionary relationships**- PHYLOGENY- the **closer** the DNA sequence between species, the **more recent** the common ancestor

Question 29

what are the two *data-based* uses of DNA sequencing

Answer 29

* ^{BIOINFORMATICS}- 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**