Plant Flashcards
Description of cell wall
Surrounds the cell outsie of the cell surface membrane is made of a polysaccharide called cellulose
Function of cell wall
Strengthens and support and prevent fron changing shape
Maintain the cell shape
Permeable and allow solutes and solvent to enter and exit
Contains pores to allow the movement of substances
What does the primary cell wall contain
Pectin
- acts like glue holds the plant cell togther
—: pectin combine positive calcium pectate
- made up of cellulose microfibrils,pectin, and matrix of hemicellulose and other shortchain carbohydrates which act as glue
- FLEXIBLE as cellulose microfibrils oriented in similar direction (parrallel)
Middle lamella description
Outermost layer of the cell
Forms after cell division
Made of pectin , calcium pectate
Function of middle lamella
Layer acts as an adhesive , sticking adjacent plant cells togther
—> giving plant stability
Description of secondary cell wall
Cellulose microfibrils laid densely at different angles to each other
—> gives cell wall strength
Develops as plant ages
More rigid + hemicellulose harden it further
Some are lignified .ie. wood
- plant fibres
What are plant fibres and uses of them
Long tubes of plant cell
Used for
- clothing
- ropes
- paper
Description of plasmodesmata
Channels of cytoplasm that pass between adajecent cell walls of plant
Function of plasmodesmata
Allow transport of substances and communication between cells
Description of pits
Thin areas of the walls with secondary thickening
Function of pits
Allow water to be transported more easily
Description of vacuole
Space inside cytoplasm filled with cell sap , surrounded by membrane called the tonoplast
Function of permanent vacuole
Storage of different substances Contain cell sap -> enzyme -> minerals -> waste product
I.e betacyanin in beetroot cells
Maintaing turgor pressure
-keeping it volved in the breakdown and isolation of unwanted chemicals in the cell
Tonoplast controls what enetr and leaves the vacuole
- allows water to enter the cell by osmosis
Description of chloroplast
Large organelle, biconcave shape
Surrounded by a double membrane , and also has membrane inside called thylakoid membrane
Contain granum made of thylakoid membrane suspended in a liquid called stroma
Contains their own DNA and have a double membrane,like mitochondria, giving a large SA for reaction to take place
Function of chloroplast
Site of photosynthesis
Contains chlorophyll green pigment that traps energy from light
Photosynthesis happen
- grana
- stroma
Similarities of chloroplast and mitochondria
Large organelle
- biconcave diamter - 4-10um
- thick 2-3 um
Contain their own DNA
Are surrounded by an outer membrane
Enormously folded inner membrane that gives a greatly increased durface area where enzyme -controlled reaction take place
difference chloroplast and mitochondria
Site of photosynthesis
Contains chorophyll , the green pigment is responsible for trapping the energy from light making it available for the plant to use
Description Amyloplast
Small organelle enclosed by a membrane contain starch granules
Colourless develop from a plant stem cell known as a leucoplast
Function amyloplast
Storage of starch grains
Store amylopectin
Comvert starch back to glucose for release when the plant requires it
Found in large amounts in starch storing area:potato tubers
What are cellulose
Cellulose is made up of long chains of beta glucose joined by 1,4 glycosidic bonds cellulose chains
Function of stem
Support
-hold the leaf to maximise obtaining sunlight for photosynthesis
- maximise the likelihood of pollination
Strength to stay upright
Movement of material
-provide the route along which the products of photosynthesis are carried
What are parenchyma
Unspecialised plant cells - can differentiate into other kinds of cells
Eg collenchyma and sclerenchyma
Act as packing in stems and roots to give support
Alive; metabolically active
Gas exchange
Function in photosynthesis , storage , and secretion
Collenchyma description
Contain thick cellulose primary cell walls - thicker at their corners
-giving mechnical strength
Support to the tissue
Alive so they can stretch so the plant grows and provide flexibility
Sclerenchyma description
Very thick lignfied cell walls and an empty lumen with no living content
Strong Secondary walls made of cellulose microfibrils positioned at right angle to each other
-some makes fibres very found in bundles
Lignin is deposited in the cell wall of these fibres in a spiral or ring pattern
—> fibre strong but also flexible
What makes the sclerenchyma strong
Lignin is deposited on the cell wall of these fibre
—> makes the fibre strong and also flexible
When the fibre is lignified the cell content dies because water cannot pass through lignin, and so the fibre becomes hollow tubes. Once this has happened these cells can no longer grow so plant growth has to be higher the stem
Whats factors makes the sclerenchyma strength if fibre
- length
- how much they are lignified(how much lignin they contain)
When the fibre is lignifed , the cell content die because water cannot pass through lignin - fibre become hollow tube
Once this happen cell can no loner grow , so plant growth has to be higher up the stem
What is sclereids
Sclerenchyma cells that are completely impregnated with lignin
Found in the cortex of the stem or individually in plant tissue
Structure of xylem
Hollow, lignified, xylem vessel made of dead cells with no end
Tubes are found togther in bundles
Function of xylem
Lumen (hollow)
Allow water + minerals transport
Lignin wall
(Stretched support + waterproof)
Pits —> allow water to pass through between different xylem
Water flow in one direction
Movement of water always upwards
Transport water and dissolved minerals ions up the stem
Description phloem
Living tissue made up of phloem cells which transport sucrose/amino acids to where it is needed for growth or to be stored as starch —> translocation
The flow through phloem can both up and down the plant
What is cambium
Layer of unspecialised plant cells that divide to form the xylem and the phloem
What is a protoxylem
First xylem the plant makes; it can stretch and grow because the walls aren’t fully lignified
The cellulose microfibrils in the walls of the xylem vessel are arranged vertically in the stem
—> increases the strength of the tube and allows it to resits compression force from the weight of the plant pressing on it
What is metaxylem
Consist of mature xylem vessel made of lignified tissue
—> the cells become impermeable to water and other substances
—> the tissue becomes stronger and more supportive but the content of the cell dies
The ends between the cells break down so the xylem forms a hollow tube which fo from root to the tops of the stem and leaves
Phloem contains and descriptive
Sieve tube element and companion cells
Living
The phloem sieve tube becomes a tube filled with phloem sap and mature phloem cells and no nucleus
They survive, cuz companion cells are active cells and is linked to sieve tube by many plasmodesmata
The sieve plates contains lots of holes to allow solute to pass through
Companion cell carry out the living function for themselves and sieve cells
—> many unfolding stories increase surface area over which they can transport sucrose into the cell cytoplasm
—> many mitochondria to supply the ATP needed for active transport of solutes
Many cells joined to make a very long tubes that run from the highest shoots to the end of the roots
Components of phloem tissue
The sieve parts are the end walls , which have lots of holes in them to allow solutes to pass through cause the break down of tonoplast and nucleus
Living cells weirdly for sieve tubes have no nucleus , a very thin layer of cytoplasm and few organelle
The phloem sieve tube becomes filled with phloem sap
The cytoplasm of adjacent cells is connected through the holes in the sieve plates
The lack of nucleus and other organelle in sieve tube element means that they cant survive in their own
-that why they have companion cells for every sieve tube element linked by many plasmodesmata
Made from living cells lined ends to ends forming sieve tube element sectioned by sieve plate surrounded with companion cells
—> companion cells control the cell activities of the sieve tube and it requires ATP from the mitochondria for active transport
What does the companion cells do for phloem tissue
Companion cells have many inner foldings increasing SA ovr which they can transport sufrose into the cell cytoplasm
They have many mitochondria to supply ATP for active transport
Role of epidermis
Outer layer if the stem
Protects the cells underneath
Contain a waxy substance cutin is cecreted to reduce water loss
Position of sclerenchyman
Outside phloem
Why do plants need water?
Plants need water for photosynthesis
- combine with CO2 and water —> glucose and oxygen using energy from sunlight
Plants need water for support
-espcially in non-woody plants the build up of water in the vacuole by osmosis cause the cell rigid and stay up right
Non-woody plant rely on the pressure as water moves into the vacuole of the cell by osmosis
-forcing the cytoplasm against the cell walls making the cell rigid
Plant need water for transport
-mineral ions are carried around the plant in the xylem in mass transport which is powered by transcription as water evaporates from the surface of the cells in the leaves and diffuses out into air
Pkant need to keep cool
-the evaporation of water form the leaves helps cool the plant
Nitrate function
Needed to make DNA and amino acids (ex enzyme , hormone, protein) and in turn proteins
Essential for growth and reproduction
Nitrate deficiency
Stunted growth
Yellow older leaves
Phosphate function
Needd for phosphate grwups in ATP and ADP and nucleic acid
Essential to energy transfer and growth
Phosphate deficiency symptoms
Very dark green leaves
Purple veins
Stunted growth
Calcium function
Combine with pectin to form calcium pectate found in middle lamella of plant cells holding the cell together
Calcium ions also contribute stability in plasma membrane by binding to the phospholipid bilayer
-important to permeability of membrane
Calcium deficiency
Growing points die back
Yellow and crinkly younger leaves
Magnesium function
Used to make/ Part of chlorophyll molecule
Essential for activation of plant enzyme needed for photosynthesis
And sythesis of nucleic acids
Magnesium deficiency
Yellow areas on older leaves
Growth slowed down
How are plant fiber useful for
Long scherenchyma and xylem vessel joined in a bundle which makes them strong and tough
—> great tensile strength
Cellulose and lignified cellulose arent easily broken down by enzyme but the matrix of pectates and other compounds can usually be removed
Flexibility -
How fibres are processed to make products
Fibers are produced through decomposer breaking dwon teh materials around the fibers after the plant dies
Quicke way is using - enzyme & chemical
What is Wood made out of
A composite material made of lignified cellulose fibre embedded in hemicellulose
Properties of wood
Very high tensile strength quite flexible
For
Weight bearing in building
Making furniture
Making Boats
How to make paper
- soak in a strong alkali such as caustic soda
- pulp consisting of cellulose and lignified cellulose left in water
- thin layers of pulp pressed into frames
- layers of pulp dry to form paper
What are plastic made out of
Synthetic Polymer
Made from oil based products
Nonsustainable due to it being non-biodegrable
—> not be broken down by decomposer
What is meant by the term tensile strength
Resisatnce of a materil to breaking under tension
What are the uses of bioplastic
Thermoplastic used to make capsule which contain drugs, easy to swallow and absorb water which allow for easy digestion
PLA (polylatic acid) has the same properties as polyethene, but is biodegradable ( made from maize)
Poly-3-hydroxybutyrate is like polypropene
(Used in ropes, bank notes and car parts )
Benefits of bioplastic
They are a sustainable resource
Bioplastic are biodegrable (less damaging to the environment than oil based when discarded)
-bacteria and fungi can usually break down bioplastic -process is very low
(A renewable resource so potentially supplies shouldnt run out)
Can be recycled
Doesnt increase CO2 emissions
- plant absorb the CO2 emitted by burning or degradation during their growth process. Therefore, there is absolutely no increase in CO2 (carbon neutrality)
How is bacteria reproduce under ideal conditions
By binary fission
- temperature
- pH level
- nutrients
- water
Risk of bacteria
Mutant pathogenic strand
Risk of contamination of the harmless culture by pathogenic microorganism from the environment
When you grow a pure stain of a microorganism , the entry of any microoganism from the air or your skin into the culture will contaminate it
Process of bacteria growth
All equipment must be sterile already before the culture is started
Once the culture is grown is doesnt leave the lab
The instrument used to add bacteria to the petri dish must be sterilized by dipping it in ethanol and passing over a bunsen burner
Leave a yellow flame bunsen burner nearby to create conviction current that will destroy airborne bacteria
All culture should be disposed of safely by sealing them in a plastic bag and sterilising them at 121c for 15 minutes under high pressure
How does plant defend against microorganism
Evolved chemical defences to kill any microbes which will invade and cause disease
Chemical defence include antiseptic compound and antibiotics
Antimicrobial extract
Plant and fungi extract antimicrobial properties
Containg chemicals that kill bacteria and fungi
Extracting drugs from plant
William withering’s digitalis soup
-> discovered that an extract of foxgloves could be used to treat drosy (extract contained the drug digitalis)
—> CHANCE OBSERVATION n a patient suffering from drospy recovered after being treated by a traditional remedy containing foxgloves
—> tested different version of the remedy eith different concentration of digitalis
—> TRIAL AND ERROR : too much digitalis poisoned his patient, whilist too little had no effect
What make it a medicine
Effective- cures, relieve, or prevents symptoms of the disease it is designed against
Safe- non toxic without acceptable side effect
Stable - can be stored from time to time and used under normal conditions
Easily taken into body and removed from it - able to get it target in the body and then get excreted
Can be made on a large scale - can be manufactrued in a pure form , cheaply , and in large quantities
Pre clinical trial
Animal studies and laboratory studies on isolated cells and tissue culture assess safely and determine whether the compound is effective against the target disease
Clinical trials phase 1
A small group of ( usually healthy) volunteer are told about the drug and given dose. The trial confirms whetehr or not the compound is being absorbed, distributed, metabolised and excreted by the body in the way predicted by the laboratory tests
- must be the same gender/sex and they must have the same geenral health levels and lfiestyle
Clinical trial phase 2
Small group of volunteer patients ( eg 100 - 300 people with the disease, are treated to determine the drug effectiveness
Clinical trials phase 3
Large group of patients (1000-3000 people) are selected and divded into two groups. One is given the compound being investigated : the second is given the placebo ( in some cases an existing treatment is used rather than a placebo). A placebo is an inactive substance that look exactly like the drug but doesnt do anything
If the result show significant improvement in the patient recieving the treatment compared to those with the placebo or standard treatment then compound being invetsigated is effective. Often a double blind trial is used which is when neither the patient nor the doctor know who is having the compound under investigation and who is having the placebo
When is the double blind trials carried out
Phase 2 and 3
Neither the doctor nor the patient knows whether the patient is receiving the new medicine, placebo or a control medicine
—> how psychological effects on the body
What happens in placebo effect
Where the patients appear to respond to the drug simply because they believe that it’ll do them well, psychological effect more than a biological effect
During certain trials, the trial will be so successful to the point it is halted early, because if it is seen that the medicineis sucessful in phase 3, then it becomes unethical not to release the medicine to treat sick people. Once the drug is seen to be safe during phase 3, the company will then apply to license the medicine so that they can sell it on world-wide level
However, the trial keep ongoing even after the medicine has been sold in the market in order to make sure that there are no risk and if there are, that they are not greater than the benefit of the medicine
Ideal growth for bacterial
Warmth- to maximise the rate enzyme-controlled reaction
Moisture- bacteria need water to dissolve nutrients in and for many chemical reaction
Nutrients- bacteria need various ions for survival (such as phosphate ions for ATP) and glucose for respiration, all of which they obtain from their external environment
Optimum pH - to maximise the rate of enzyme-controlled reactions
Oxygen- required for species of bacteria that respire aerobically
Formation of cellulose
Beta glucose are held together by 1,4-glycosidic bonds where one monomer flips (inversion, every 2 beta glucose)
Long and straight , unbranched
Cellulose form straight chain allowing cellulose molecules to be close together forming hydrogen bonds -huge number hydrogen bonds form making them strong -microfibrils
Group of microfibrils form together to form macrofibrils
And macrofibrs form together to form fibre
How are the cellulose hold togther
Cellulose fibrils are deposited in layers whihc held togther by a matrix of hemicellulose and other short chain carbohydrates
Thylakoids description
Membrane bound flattened discs
Function of thylakoids
Where light dependent reaction takes place containing chlorophyll and enzyme needed for light dependant reactions
Granum
Thylakoid stacked ontop of each other
Function of granum
By stacking the thylakoid into grana - light can be adsorbed more effiently
How are thylakoid connected to each other
Thylakoid on different grana are connected by lamelle ( flattened membrane) play a role in a light dependant reactions and allow chemicals to pass between the grana
Stroma
Fluid material called stroma Where light independent reaction take place
-containing the enzyme needed for light independant reactions
Starch granules
End product glucose - glucose can be converted into polysaccharides starch which is stored in the chloroplast as starch granules
What is a protoxylem
First xylem the plant makes : it can stretch and grow because the wall is not fully lignified
- xylem structure has a vertically arrangement of cellulose microfibrils whihc give strength and resistance of the compression force
What is a metaxylem
Consists of mature xylem vessel made of lignifed tissue
More lignin added this cause the xylem become impermeable to water and other substances
The end wall breaks down forming hollow tube
Define transcription stream
The movement of water up from the soil through the root hair cells, across the root to the xylem, then up the xylem, across the leaf until it is lost by evaporation from the leaf cells and diffuses out the stomata down a concentration gradient
Define translocation
The active movement of substance around a plant in the phloem
What process is the water and mineral transpored called
Water and minerals ions are transported from roots to leaves by transcription stream
How does the water move out by
The water moves out to the surrounding cells through the pits in the walls of xylem vessel
How does the xylem only travel upwards
The vessels are narrow enough to ensure that water travels upwards in an unbroken column
How does the substances flow through the phloem
Phloem consists of sieve tube and companion cells
Inside the sieve tube there are sieve plates for the mass flows through the holes in the plater
Companion cells are very active cells, have lotsof mitochondria to provide energy in the active process
These two cells are linked to each other by many plasmodesmata
The cell membranes of companion cells have many infolding that increase the SA over which they can transport sucrose into cell cytoplasm
Summarise the retting process
Involves the action of the microorganism and moisture on plants to dissolve or rot away the cellular tissue so that it facilitates the separation of the fibre from the stem
How does spinning make a thread
Short, single fibre found around cotton seeds are spun to form long continuous threads with are then woven togther to make fabric
Name some synthetics fibre
Rylon and polyester
Limitation of synthetic fibre
Made from crude oil
Non sustainble resource —> expensive
Dont breathe, dont absorb liquid ( sweat)
Sustainability
Using material which can be replaced .
Plants are vital in developing sustainble resources
Why do we need to use more susitable alternative for making materials
Far less waste than other types of material such as plastic
- less landfill waste
- less energy consumption and less impact on environment as a whole
What is composite material
Combination of two material with different physical and chemical properties
Description of wood
Made of lignified cellulose fibre embedded in hemicellulose and lignin
Function of wood and properties that make it good
very resistant to compression-
high tensile strength as it is quite
flexible making is suitable for weight bearing in buildings and making furniture and boats
Lignin gives strength but Is lightweight
Renewable /sustainable
Doesn’t expand in heat but dries out and gets stronger
Good heat and sound insulator
Doesn’t crack when cut or nailed and keeps its strength
Define carbon neutral
A process where no net carbon is released into the atmosphere
Describe how wood is carbon neutral when burnt
Wood locks up carbon dioxide and is sustainavle resource
Taking in carbon as it grows and releasing it as it is burnt
Disadvantages of bioplastic
More expensive than oil based plastic currently
Can be conflicted between use of crops for food and for bioplastic
Release methane gas when decomposed
Increase competition for food source
They need set of condition to biodegrade
Benefits of oil based plastic
Doesnt break
Lightweight
Dispensable
Durable
Disadvantages of oil based plastic
Nonxbiodegrable
-cannot be degraded by natural occuring microorganism such as bacteria and fungi
Can cause marine life to die through intoxification
Not sustainable
Why is it important to take great care when culturing microorganism ?
- Even if the microorganism you are planning to culture is completely harmless , there is always the risk of a mutant strain arising that may be pathogenic
- there is a risk of contamination of the culture by pathogenic microorganism from the environment
- when you grow a pure strain of a microorganism, the entry of any microogranims from the air or your skin into the culture will contaminate it
How to culture the bacteria
The instrument used for inoculating the agar plate(adding the bacteria to the plate) must be sterislised in a bunsen burner flame.
(May leave it in yellow flame on the lab bench to create convection currents to carry airborne bacteria away from the plate
All cultures should be disposed of safely by sealing them in plastic bags and sterislising them 121c for 15 mins under high pressure before throwing them away.
Plant defences against microorganism
Antimicrobial plant extract by using disc to soak with the plant extract and put on the cultured agar to investigate the growth of bacteria ( to see a clear area around the disc)
Testing drugs used ot be trial and error
William withering used fox gloces to treat drospy (swelling brought by heart failure) this extract contain the drug digitalis
Withering made a chance observation - a patient suffering from drospy made a good recovery after being treated with a traditional remedy containing foxgloves.
Withering knew foxglove were poisonous, so he started testing different versions of the remedy with different concentrationof digitalis - digilis soup
Too much digitalis poisoned his patient, while too little had no effect
It was through this crude method of trial error that he discovered the right amount to give to a patient
Phase 1
This involves testing a new drug on a small group of healthy individuals. It done to find out things like safe dosage, if there are any side effects and how the cody reacts to the drug
Reviewed by independent scientist (peer review) to see if work can progress to phase 2 to avoid bias
Phase 2
If a drug passes phase 1 it will then be tested in a larger group people (this time illness patients) to see how well the drug actually work
To find the optimum concentration of the drug or the side effect of the drug
Phase 3
During this phase the drug is compared to existing treatments . It involve testing the drug on hundreds or even thousands of patient
Using a large sample size makes the results of the test more reliable
Patient are randomly split into two group- one group recives the new treatment and the other group recieve the placebo. This allows scientist to tell if the any better than existing drugs
Analyse result with appropriate statistical test/ test for significant difference
Drug tested on large groups of people who have the disease
To find optimum concentration of the disease, side effects, long term effect
Placebos
In phase 2 clinical trial the patients are split into two groups. One group is given the drug and other is given a placebo - an inactive substance that looks exactly like the drug but doesnt actually do anything
Patient often show a placebo effect - where they show some improvement because they believe that they’re recieving treatment.
Giving half the patient a placebo allows researchers to see if the drug actually works
Double blind study design
Phase 2 and 3 clinical trials are usually double blind - neither the patients nor the doctors know whos been given the new drug and whos been given the placebo ( or old drugs). This reduces bias in the results because the attitudes of the patients and doctors cant affect the results
Eg if a doctor knows someone has recived the real drug, they may think they’ve improved more than they actually have - but if they dont know this cant happen
Give three factors which need to be in place for bacteria to grow well
Nutrients
Temperature
Water
What are aseptic technique and why is it so important to use them when growing bacteria in the laboratory
Aseptic techniques keep the experimental apparatus sterile and free from contamination with microorganism other than those you are choosing to grow. This is very important because otherwise your culture could be contaminated by dangerous bacteria or you could accidentally contaminate your environment with potentially dangerous microorganism
Some plants make antibacterial chemicals explain the advantages this gives to the plant
Plants are frequently attacked by bacteria which grow on or in the plant and damage or destroy them . The plants make antibacterial chemicals which kill invading bacterial and so protect the plant from harm
Give and expalin two advantages of using manufacturing drugs over plant extract
- levels of chemicals vary in plants
Manufacturing drugs known repeatable dose of active ingredients every time
- plants extract contain many other things apart from the desired drugs and some of these may be harmful
- using manufactured drugs, the active ingredient is pure and only mixed with known inert substance to make the pill or medicine
Discuss the ethics of carrying out phase 1 human trials on healthy volunteers
Carrying out phase 1 trials on healthy volunteers is ethical because people volunteer to take part or because it has the potential to give great benefit to many people.
—> carrying out phase 1 trials on healthy volunteer is not ethical because some people may be persuaded to take part because they need money
Carry out phase 1 trials on people who have the disease because the drug might work effectively in people who are ill but cause problem for healthy people have a different body chemistry
Flow chart development of a new medicines from a plant thought to have medicinal properties
Identification of active ingredient —>
lab preparation of active ingredient —>
possible modification for improved effectiveness
—> testing on cell/tissue culture —>
tests on animals —>
phase 1 trials on human volunteers —>
phase 2 trials on small number of patients —>
phase 3 trials on large number of patients —>
licensing of new drug - continueing of monitoring of side effect
Sometime a doctor may want to prescribe a drug before it has completed full human trial . Is it ever ethical to use a drug before it has undegone all stages
For: may save a person life, even if it doesnt help the individual , they had nothing to lose and it will give information that may help other
Against: may risk that person life more than not using the treatment as it may have terrible side effects . It is never ethical to use people as experimental organism
Food/nutrients for bacteria
Glucose/sugar for respiration
Bacteria- optimum temperature
Bacterial metabolism is regulated by enzyme which have optimum temperature they work at
Bacteria - pH conditions
Optimum pH for enzyme to catalyze metabolic reactions/ prevent denaturation of enzyme
Bacteria prefer slightly alkaline,line conditions
Bacteria - oxygen condition
Many microorganisms require oxygen for metabolism and are known as obligate aerobes
Oxygen required for aerobic respiration
Bacteria - water requirement
Hydration , formation of cytoplasm, hydro lyric reaction acts as a solvent
Warm temperatures
Optimum temperature for enzyme to catalyze metabolic reactions/ prevent denaturation of enzyme
What is quinine used for (plants)
Used to prevent malaria comes from cinchona tree
What is it used for Salicylic acid
From willow trees
Brewed or chewed into a drink to relieve pain and fever
—> aspirin
Anal glands of dead beavers used for
To relief pain
1)wave inculcating loop and flame the culture bottleneck in Bunsen burner
To sterilize / kill bacteria on loop to avoid contamination
2) allow loop to cool
To not kill bacteria that the experiment is trying to grow
3) leave the Bunsen burner on orange flame
Create convection current to carry airborne bacteria away from plates
4) streak loop across surface of agar, avoiding digging into agar
To gain complete coverage on surface
Tape lid closed, but incompletely
Allows oxygen to enter Petri dish and prevent growth harmful anaerobic bacteria
Store Petri dish upside down
Prevent condensation from collecting on bacteria colonies
Incubate at temperature no higher than 30c
Prevent growth of harmful human pathogens at higher body temperature
Place culture in a sealed plastic tubes, place in higher pressure chambers at 121c for 15 mins
Dispose of culture safely , to kill any remaining bacteria
Hazard
People
What are the hazard, risk and safety precaution and risk level
Disinfectant , flammable
Keep away from naked flame
Put out fire; seek assistance
Low
Hazard, risk and safety precaution , in emergency risk level /Biohazard
Biohazard
Contamination infection
Use disinfectant
Wash hands with soap after disinfectant
Don’t incubate at human body temperature
Don’t open agar plate post incubation
Seek assistance
Low / medium (depends on likeliness of bacteria sample used to cause infection)
Hazard, risk and safety precaution, in emergency risk level (naked flame)
Fire hazard
Keep away from flammable materials
Tie up long Kari
Keep away from edge of desk
Put out fire, seek assistance , run burns under cold water immediately
Low
Hazard, risk, safety precaution, one,emergency , risk level (methylated spirit)
Flammable and toxic
Keep away from naked flame
Don’t not ingest
Wear gloves and goggles
Seek assistance
Medium
Process of making cellulose
Is a polymer consisting of long chain of beta-glucose joined together by 1,4 glycosidic bonds
As beta glucose is an isomer of beta glucose to form the 1,4 glycosidic bonds consecutive beta glucose molecules must be 180 to each other
Due to the inversion fo the beta glucose molecules many hydrogen bonds form between between the long chains giving cellulose its strength
Cellulose function
Main structural component of cell walls due to its strength which is a result of many hydrogen bonds found between the parallel chains of micro fibrils
The high tensile strength of cellulose allows it to be stretched without breaking which makes it possible for cell walls to withstand turn or pressure
- The cellulose fibres and other molecules (eg. lignin) found in the cell wall form a matrix which increases the strength of the cell walls
- The strengthened cell walls provides support to the plant
- Cellulose fibres are freely permeable which allows water and solutes to leave or reach the cell surface membrane
As few organisms have the enzyme (cellulase) to hydrolyse cellulose it is a source of fibre
Advantages of bio plastic
Renewable
Can be used for future generations
Biodegradable
Describe how companion cells in phloem contribute to translocation
They have mitochondria to make ATP to actively load sucrose into the sieve tube element
Explain how the companion cells are adapted to their function
They contain nucleus and organelle such as mitochondria there are connecting plasmodesmata betweeen them and the sieve tube element
Clothing made from cotton
Cotton fibre are very strong
Good heat insulator
Breathable
Allow sweat to evaporate
Flexible
Cotton is renewable
Cotton plants while growing remove carbon dioxide from atmosphere
Describe the arrangement of cellulose fibres in a plant cell wall
Long straight cellulose chains held together by many hydrogen bonds, bundled into micro fibrils which are deposited in layers and held together by a matrix of hemicellulose
Drug development before humans
1)Tested on cells or tissues
2)Mouse
Rabbit
Monkey
—> closely related
—> same metabolic pathway
Suggest why some drugs are rejected at each of these stages
Preclinical - animals harmed by drugs
Phase 1 idea that drugs had side effects
Phase 2 - drug had no effect on condition or less effective
Phase 3 drug was not successful enough compared to the placebo
Why it is important that these technique are carried out under aseptic conditions
To prevent infection of plants
To prevent infections of bacteria
Compete for nutrients
Bacteria could produce chemicals that could poison the plants
Describe how amyloplast and chloroplast differ
Amyloplast
Store starch
Chloroplast
Have complex structure folded membrane that contain chlorophyll which traps energy from sunlight so that plants make their own food
Similarities of xylem and phloem
They both are plant transport tissue
Both have a lot of water moving through them
Both found together in vascular bundle in plants
What is a placebo
Inactive substance resembling a drug being trialed which is used as an experimental control
Why animal testing
How the drug may have an effect on other tissue
Needing to find out effect on organs
Mammals are sued due to having similar metabolism
Find out whether drug is safe
-> this will show if the drug gets taken into the cells, if
Phase 1
New drug is given to small number of healthy volunteers
—> to check that the drugs works as expected in the human body and doesn’t cause an unexpected side effects
They are monitored by independent scientists
Phase 2
Small group of people given the New drugs is given to patients with the disease
Or sometimes divided with the placebo
The volunteer patients are closely monitored to find out more about the ideal dose the effectiveness of the drug and any side effects
Phase 3
Large group of people with the disease are given the drug
Double blind trials are carried out in phase 2 and 3
—> the doctor nor the patients knows whether the patient is receiving the new medicine , a control medicine or a placebo
Phase 3 are used to confirm the effectiveness and safety of the new drug
Data on effectiveness side effects and other information are collected and assessed to see if there are any statistically significant difference between the new medicine and the placebo or the currently available drug
Suggest reason why some drugs are rejected at each of these stages
Preclinical - to phase 1 : that animal harmed by drug
Phase 1 to phase 2 that drug side effect
Phase 2 to phase 3 patient were not cured/ drug had no effect on condition/ drug was less effective than existing drugs
Phase 3 onwards; drug wasn’t successful enough compared to the placebo
