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Plant Flashcards

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1
Q

Description of cell wall

A

Surrounds the cell outsie of the cell surface membrane is made of a polysaccharide called cellulose

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2
Q

Function of cell wall

A

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

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3
Q

What does the primary cell wall contain

A

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)
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4
Q

Middle lamella description

A

Outermost layer of the cell

Forms after cell division

Made of pectin , calcium pectate

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5
Q

Function of middle lamella

A

Layer acts as an adhesive , sticking adjacent plant cells togther

—> giving plant stability

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6
Q

Description of secondary cell wall

A

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

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7
Q

What are plant fibres and uses of them

A

Long tubes of plant cell

Used for

  • clothing
  • ropes
  • paper
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8
Q

Description of plasmodesmata

A

Channels of cytoplasm that pass between adajecent cell walls of plant

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9
Q

Function of plasmodesmata

A

Allow transport of substances and communication between cells

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10
Q

Description of pits

A

Thin areas of the walls with secondary thickening

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11
Q

Function of pits

A

Allow water to be transported more easily

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12
Q

Description of vacuole

A

Space inside cytoplasm filled with cell sap , surrounded by membrane called the tonoplast

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13
Q

Function of permanent vacuole

A 
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

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14
Q

Description of chloroplast

A

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

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15
Q

Function of chloroplast

A

Site of photosynthesis

Contains chlorophyll green pigment that traps energy from light

Photosynthesis happen

  • grana
  • stroma
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16
Q

Similarities of chloroplast and mitochondria

A

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

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17
Q

difference chloroplast and mitochondria

A

Site of photosynthesis

Contains chorophyll , the green pigment is responsible for trapping the energy from light making it available for the plant to use

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18
Q

Description Amyloplast

A

Small organelle enclosed by a membrane contain starch granules

Colourless develop from a plant stem cell known as a leucoplast

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19
Q

Function amyloplast

A

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

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20
Q

What are cellulose

A

Cellulose is made up of long chains of beta glucose joined by 1,4 glycosidic bonds cellulose chains

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21
Q

Function of stem

A

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

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22
Q

What are parenchyma

A

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

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23
Q

Collenchyma description

A

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

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24
Q

Sclerenchyma description

A

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

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25
Q

What makes the sclerenchyma strong

A

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

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26
Q

Whats factors makes the sclerenchyma strength if fibre

A
  • 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

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27
Q

What is sclereids

A

Sclerenchyma cells that are completely impregnated with lignin

Found in the cortex of the stem or individually in plant tissue

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28
Q

Structure of xylem

A

Hollow, lignified, xylem vessel made of dead cells with no end
Tubes are found togther in bundles

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29
Q

Function of xylem

A

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

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30
Q

Description phloem

A

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

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31
Q

What is cambium

A

Layer of unspecialised plant cells that divide to form the xylem and the phloem

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32
Q

What is a protoxylem

A

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

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33
Q

What is metaxylem

A

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

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34
Q

Phloem contains and descriptive

A

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

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35
Q

Components of phloem tissue

A

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

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36
Q

What does the companion cells do for phloem tissue

A

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

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37
Q

Role of epidermis

A

Outer layer if the stem

Protects the cells underneath

Contain a waxy substance cutin is cecreted to reduce water loss

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38
Q

Position of sclerenchyman

A

Outside phloem

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39
Q

Why do plants need water?

A

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

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40
Q

Nitrate function

A

Needed to make DNA and amino acids (ex enzyme , hormone, protein) and in turn proteins
Essential for growth and reproduction

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41
Q

Nitrate deficiency

A

Stunted growth

Yellow older leaves

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42
Q

Phosphate function

A

Needd for phosphate grwups in ATP and ADP and nucleic acid

Essential to energy transfer and growth

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43
Q

Phosphate deficiency symptoms

A

Very dark green leaves

Purple veins

Stunted growth

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44
Q

Calcium function

A

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

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45
Q

Calcium deficiency

A

Growing points die back

Yellow and crinkly younger leaves

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46
Q

Magnesium function

A

Used to make/ Part of chlorophyll molecule

Essential for activation of plant enzyme needed for photosynthesis
And sythesis of nucleic acids

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47
Q

Magnesium deficiency

A

Yellow areas on older leaves

Growth slowed down

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48
Q

How are plant fiber useful for

A

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 -

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49
Q

How fibres are processed to make products

A

Fibers are produced through decomposer breaking dwon teh materials around the fibers after the plant dies
Quicke way is using - enzyme & chemical

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50
Q

What is Wood made out of

A

A composite material made of lignified cellulose fibre embedded in hemicellulose

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51
Q

Properties of wood

A

Very high tensile strength quite flexible

For
Weight bearing in building
Making furniture
Making Boats

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52
Q

How to make paper

A
  • 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
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53
Q

What are plastic made out of

A

Synthetic Polymer

Made from oil based products
Nonsustainable due to it being non-biodegrable
—> not be broken down by decomposer

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54
Q

What is meant by the term tensile strength

A

Resisatnce of a materil to breaking under tension

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55
Q

What are the uses of bioplastic

A

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 )

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56
Q

Benefits of bioplastic

A

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)

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57
Q

How is bacteria reproduce under ideal conditions

A

By binary fission

  • temperature
  • pH level
  • nutrients
  • water
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58
Q

Risk of bacteria

A

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

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59
Q

Process of bacteria growth

A

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

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60
Q

How does plant defend against microorganism

A

Evolved chemical defences to kill any microbes which will invade and cause disease

Chemical defence include antiseptic compound and antibiotics

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61
Q

Antimicrobial extract

A

Plant and fungi extract antimicrobial properties

Containg chemicals that kill bacteria and fungi

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62
Q

Extracting drugs from plant

A
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63
Q

William withering’s digitalis soup

A

-> 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

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64
Q

What make it a medicine

A

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

65
Q

Pre clinical trial

A

Animal studies and laboratory studies on isolated cells and tissue culture assess safely and determine whether the compound is effective against the target disease

66
Q

Clinical trials phase 1

A

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
67
Q

Clinical trial phase 2

A

Small group of volunteer patients ( eg 100 - 300 people with the disease, are treated to determine the drug effectiveness

68
Q

Clinical trials phase 3

A

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

69
Q

When is the double blind trials carried out

A

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

70
Q

What happens in placebo effect

A

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

71
Q

Ideal growth for bacterial

A

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

72
Q

Formation of cellulose

A

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

73
Q

How are the cellulose hold togther

A

Cellulose fibrils are deposited in layers whihc held togther by a matrix of hemicellulose and other short chain carbohydrates

74
Q

Thylakoids description

A

Membrane bound flattened discs

75
Q

Function of thylakoids

A

Where light dependent reaction takes place containing chlorophyll and enzyme needed for light dependant reactions

76
Q

Granum

A

Thylakoid stacked ontop of each other

77
Q

Function of granum

A

By stacking the thylakoid into grana - light can be adsorbed more effiently

78
Q

How are thylakoid connected to each other

A

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

79
Q

Stroma

A

Fluid material called stroma Where light independent reaction take place

-containing the enzyme needed for light independant reactions

80
Q

Starch granules

A

End product glucose - glucose can be converted into polysaccharides starch which is stored in the chloroplast as starch granules

81
Q

What is a protoxylem

A

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
82
Q

What is a metaxylem

A

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

83
Q

Define transcription stream

A

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

84
Q

Define translocation

A

The active movement of substance around a plant in the phloem

85
Q

What process is the water and mineral transpored called

A

Water and minerals ions are transported from roots to leaves by transcription stream

86
Q

How does the water move out by

A

The water moves out to the surrounding cells through the pits in the walls of xylem vessel

87
Q

How does the xylem only travel upwards

A

The vessels are narrow enough to ensure that water travels upwards in an unbroken column

88
Q

How does the substances flow through the phloem

A

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

89
Q

Summarise the retting process

A

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

90
Q

How does spinning make a thread

A

Short, single fibre found around cotton seeds are spun to form long continuous threads with are then woven togther to make fabric

91
Q

Name some synthetics fibre

A

Rylon and polyester

92
Q

Limitation of synthetic fibre

A

Made from crude oil
Non sustainble resource —> expensive

Dont breathe, dont absorb liquid ( sweat)

93
Q

Sustainability

A

Using material which can be replaced .

Plants are vital in developing sustainble resources

94
Q

Why do we need to use more susitable alternative for making materials

A

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
95
Q

What is composite material

A

Combination of two material with different physical and chemical properties

96
Q

Description of wood

A

Made of lignified cellulose fibre embedded in hemicellulose and lignin

97
Q

Function of wood and properties that make it good

A

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

98
Q

Define carbon neutral

A

A process where no net carbon is released into the atmosphere

99
Q

Describe how wood is carbon neutral when burnt

A

Wood locks up carbon dioxide and is sustainavle resource

Taking in carbon as it grows and releasing it as it is burnt

100
Q

Disadvantages of bioplastic

A

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

101
Q

Benefits of oil based plastic

A

Doesnt break

Lightweight

Dispensable

Durable

102
Q

Disadvantages of oil based plastic

A

Nonxbiodegrable
-cannot be degraded by natural occuring microorganism such as bacteria and fungi

Can cause marine life to die through intoxification

Not sustainable

103
Q

Why is it important to take great care when culturing microorganism ?

A
  • 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
104
Q

How to culture the bacteria

A

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.

105
Q

Plant defences against microorganism

A

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)

106
Q

Testing drugs used ot be trial and error

A

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

107
Q

Phase 1

A

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

108
Q

Phase 2

A

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

109
Q

Phase 3

A

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

110
Q

Placebos

A

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

111
Q

Double blind study design

A

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

112
Q

Give three factors which need to be in place for bacteria to grow well

A

Nutrients

Temperature

Water

113
Q

What are aseptic technique and why is it so important to use them when growing bacteria in the laboratory

A

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

114
Q

Some plants make antibacterial chemicals explain the advantages this gives to the plant

A

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

115
Q

Give and expalin two advantages of using manufacturing drugs over plant extract

A
  • 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
116
Q

Discuss the ethics of carrying out phase 1 human trials on healthy volunteers

A

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

117
Q

Flow chart development of a new medicines from a plant thought to have medicinal properties

A

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

118
Q

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

A

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

119
Q

Food/nutrients for bacteria

A

Glucose/sugar for respiration

120
Q

Bacteria- optimum temperature

A

Bacterial metabolism is regulated by enzyme which have optimum temperature they work at

121
Q

Bacteria - pH conditions

A

Optimum pH for enzyme to catalyze metabolic reactions/ prevent denaturation of enzyme
Bacteria prefer slightly alkaline,line conditions

122
Q

Bacteria - oxygen condition

A

Many microorganisms require oxygen for metabolism and are known as obligate aerobes

Oxygen required for aerobic respiration

123
Q

Bacteria - water requirement

A

Hydration , formation of cytoplasm, hydro lyric reaction acts as a solvent

124
Q

Warm temperatures

A

Optimum temperature for enzyme to catalyze metabolic reactions/ prevent denaturation of enzyme

125
Q

What is quinine used for (plants)

A

Used to prevent malaria comes from cinchona tree

126
Q

What is it used for Salicylic acid

A

From willow trees

Brewed or chewed into a drink to relieve pain and fever

—> aspirin

127
Q

Anal glands of dead beavers used for

A

To relief pain

128
Q

1)wave inculcating loop and flame the culture bottleneck in Bunsen burner

A

To sterilize / kill bacteria on loop to avoid contamination

129
Q

2) allow loop to cool

A

To not kill bacteria that the experiment is trying to grow

130
Q

3) leave the Bunsen burner on orange flame

A

Create convection current to carry airborne bacteria away from plates

131
Q

4) streak loop across surface of agar, avoiding digging into agar

A

To gain complete coverage on surface

132
Q

Tape lid closed, but incompletely

A

Allows oxygen to enter Petri dish and prevent growth harmful anaerobic bacteria

133
Q

Store Petri dish upside down

A

Prevent condensation from collecting on bacteria colonies

134
Q

Incubate at temperature no higher than 30c

A

Prevent growth of harmful human pathogens at higher body temperature

135
Q

Place culture in a sealed plastic tubes, place in higher pressure chambers at 121c for 15 mins

A

Dispose of culture safely , to kill any remaining bacteria

136
Q

Hazard

A
137
Q

People

A
138
Q

What are the hazard, risk and safety precaution and risk level

A

Disinfectant , flammable

Keep away from naked flame

Put out fire; seek assistance

Low

139
Q

Hazard, risk and safety precaution , in emergency risk level /Biohazard

A

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)

140
Q

Hazard, risk and safety precaution, in emergency risk level (naked flame)

A

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

141
Q

Hazard, risk, safety precaution, one,emergency , risk level (methylated spirit)

A

Flammable and toxic

Keep away from naked flame

Don’t not ingest

Wear gloves and goggles

Seek assistance

Medium

142
Q

Process of making cellulose

A

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

143
Q

Cellulose function

A

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

144
Q

Advantages of bio plastic

A

Renewable
Can be used for future generations

Biodegradable

145
Q

Describe how companion cells in phloem contribute to translocation

A

They have mitochondria to make ATP to actively load sucrose into the sieve tube element

146
Q

Explain how the companion cells are adapted to their function

A

They contain nucleus and organelle such as mitochondria there are connecting plasmodesmata betweeen them and the sieve tube element

147
Q

Clothing made from cotton

A

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

148
Q

Describe the arrangement of cellulose fibres in a plant cell wall

A

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

149
Q

Drug development before humans

A

1)Tested on cells or tissues

2)Mouse
Rabbit
Monkey

—> closely related
—> same metabolic pathway

150
Q

Suggest why some drugs are rejected at each of these stages

A

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

151
Q

Why it is important that these technique are carried out under aseptic conditions

A

To prevent infection of plants

To prevent infections of bacteria

Compete for nutrients

Bacteria could produce chemicals that could poison the plants

152
Q

Describe how amyloplast and chloroplast differ

A

Amyloplast

Store starch

Chloroplast
Have complex structure folded membrane that contain chlorophyll which traps energy from sunlight so that plants make their own food

153
Q

Similarities of xylem and phloem

A

They both are plant transport tissue

Both have a lot of water moving through them

Both found together in vascular bundle in plants

154
Q

What is a placebo

A

Inactive substance resembling a drug being trialed which is used as an experimental control

155
Q

Why animal testing

A

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

156
Q

Phase 1

A

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

157
Q

Phase 2

A

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

158
Q

Phase 3

A

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

159
Q

Suggest reason why some drugs are rejected at each of these stages

A

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

Biology (27 decks)

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