Edexcel Biology Unit 2

Front 1

Compare Eukaryotic and Prokaryotic cells in terms of structure:

Back 1

Prokaryotic: E.Coli Bacterium

-very small. -circular DNA

-cell wall made from polysaccharide

-few organelles, no mitochondria

-small ribosomes

Eukaryotic: Liver cell.

-larger - linear DNA -nucleus present -cellulose cell wall -large ribosomes

Front 2

Draw and describe the Nucleus and its Function:

Back 2

organelle surrounded by nuclear envelope with double membrane and contains many pores. Contains chromatin and nucleolus.

Function:

pores allow substances to move into and out of nucleus and cytoplasm. Nucleolus makes ribosomes.

Front 3

Draw and describe the Lysosome and its function

Back 3

Round organelle surrounded by membrane, no clear internal structure.

Function: contains digestive enzymes used to digest invading cells or break down worn out organelles.

Front 4

Draw and describe a Vesicle and its structure:

Back 4

A small fluid-filled sac in the cytoplasm surrounded by membrane.

Function: transports substances in and out of cell. Some formed at Golgi Apparatus or ER

Front 5

Draw and describe a ribosome and its structure:

Back 5

A very small organelle that floats free in the cytoplasm or is attached to the RER.

Function: site where proteins are made.

Front 6

Draw and describe the ER:

Back 6

there are two types rough, and smooth. They are a system of membranes enclosing a fluid filled space. RER is covered with ribosomes.

Functions: the smooth ER synthesizes and processes lipids meanwhile the rough ER folds and processes proteins that have been made at ribosomes.

Front 7

Describe and draw the Golgi Apparatus

Back 7

A group of fluid filled sacs. Vesicles often seen at the edges of these sacs.

Function: processes and packages new lipids and proteins. Also makes lysosomes.

Front 8

Describe and draw Centrioles:

Back 8

hollow cylinders containing a ring of microtubules (tiny protein cylinders).

Function:

involved in separation of chromosomes during cell division.

Front 9

Draw and describe Mitochondria:

Back 9

they're usually oval shaped and have a double membrane - the inner one is folded to form structures called cristae. Inside is the matrix which contains enzymes involved in respiration.

Function: site of aerobic respiration where ATP is produced. Found in cells that are very active and require a lot of energy.

Front 10

Explain the process of protein transport:

Back 10

1)proteins are made at ribosomes. 2) the ribosomes at the RER make proteins that are excreted or attached to cell membrane. Free ribosomes make proteins that stay in the cytoplasm. 3)Proteins now made at the RER are folded and processed. 4) they are transported from the ER to the Golgi apparatus in vesicles. 5)At Golgi apparatus, they may undergo further processing. 6) proteins enter more vesicles to be transported around the cell.

Front 11

Describe the structure of squamous epithelium tissue and where it is found:

Back 11

they form a single layer of flat cells lining a surface called the basement membrane. Found in alveoli.

Front 12

Describe the function of Xylem tissue and what it includes:

Back 12

is a plant tissue with two jobs - it transports water around the plant and supports the plant.

It contains Xylem vessels and parenchyma cells.

Front 13

Describe the structure of the leaf of a plant and what each part does:

Back 13

1)lower dermis: contains stomata to let air in and out for gas exchange.

2) Spongy mesophyll: full of spaces to let gases circulate.

3)Palisade mesophyll: most photosynthesis occurs here.

4)Xylem: carries water to leaf

5)Phloem: carries sugars away from leaf.

6)Upper dermis: covered in a waterproof waxy cuticle to prevent water loss.

Front 14

Describe different tissues that form the lung and how it assists the lungs in functioning correctly:

Back 14

-Squamous epithelium tissue: surrounds the alveoli in gas exchange as it is moist and thin.

-Fibrous connective tissue: helps force air out of lungs when exhaling

-Blood vessels: capillaries surround lungs and help carry different exchanged gas through the blood stream.

Front 15

What organs form the respiratory system?

Back 15

-lungs

-trachea

-larynx

-nose

-mouth

-diaphragm

Front 16

Define the term tissue:

Back 16

this is when similar cells are grouped together to form .... tissue.

Front 17

Define organ:

Back 17

this is when different tissues come to form an organ.

Front 18

Describe the stages of the cell cycle:

Back 18

1)G1 growth

2)S1 synthesis (DNA replicates)

3) G2 further growth (proteins made

4) M1 mitosis.

and then the process repeats itself again.

Front 19

What is mitosis needed for?

Back 19

1)it is needed for the growth of multicellular organisms and for repairing damaged tissues.

AND

2)asexual reproduction (e.g plants and fungi)

Front 20

Describe the entire process of Interphase:

Back 20

The cell's DNA is unravelled and replicated to double its genetic content. Organelles are also replicated so it has spare ones and ATP content is increased.

Front 21

Briefly state the 4 stages of mitosis:

Back 21

1) Prophase

2)Metaphase

3)Anaphase

4) Telophase

(remember: P-MAT) ;)

Front 22

Describe what happens in Prophase:

Back 22

the chromosomes condense, getting shorter and fatter. The centrioles start moving to opposite ends of the cell, forming a network of protein fibres across it called the spindle. Nuclear envelope breaks down and chromosomes lie free in the cytoplasm

Front 23

Describe what happens in Metaphase:

Back 23

the chromosomes line up along the middle of the cell and become attached to the spindle by their centromere.

Front 24

What happens in Anaphase:

Back 24

the centromeres divided separating the sister chromatids. The spindles contract, pulling chromatids to opposite ends of the cell, centromere first.

Front 25

What happens in Telophase:

Back 25

the chromatids reach opposite poles on the spindle. They uncoil becoming long again and the nuclear envelope reforms around each set of chromosomes so that there are 2 nuclei. The cytoplasm divides by pinching off to form two cells that are genetically identical.

Front 26

Describe the Experiment for Mitosis:

Back 26

1)cut the tip from a growing root (broad bean) should be around 5mm long. 2)place root tip in watch glass and add a few drops of HCL. 3)add a few drops of schiff's reagent so that chromosomes become darker. 4) warm glass using bunsen burner. 5)place root tip on microscope slide and use mounted needle to speed cells thinly. 6) place more stain and cover slip. 7) warm slide to intensify stain. 8) observe mitosis.

Front 27

What are gametes?

Back 27

these are the male and female sex cells

Front 28

Define Zygote:

Back 28

a fertilized egg with chromosomes from both sperm and egg

Front 29

In plants, where are the female and male gametes located?

Back 29

Male: pollen grains

Female: ovules

Front 30

How many chromosomes do gametes have?

Back 30

23 (half)

Front 31

Describe the structure of a sperm cell and each of their functions:

Back 31

Acrosome (in head): contains digestive enzymes to break down egg's cell's zona pellucida to penetrate egg.

Flagellum: tail used to swim

Mitochondria: lots of energy taken from here for swimming.

Front 32

Describe the structure of an egg cell and each of their functions:

Back 32

-Nucleus: contains genetic material.

-Cell membrane.

-Zona pellucida: protective layer sperm must penetrate.

-Follicle cells: form protective coating.

Front 33

What is meiosis:

Back 33

this is a form of cell division that occurs in the reproductive organs to produce gametes.

Front 34

Describe the process of Meiosis:

Back 34

1) DNA replicates so that there are 2 identical copies of each chromosome called chromatids. 2)DNA condenses to form double-armed chromosomes with sister chromatids. 3)Chromosomes arrange themselves into homologous pairs (matching pairs from male and female). This is where crossing over begins where chromatids twist around each other and different combinations of alleles form (independent assortment). Then, the first division occurs separating the homologous pairs. Then, the second division occurs where the sister chromatids are separated. Four new cells have now formed that are genetically different from each other.

Front 35

Define Independent Assortment:

Back 35

this is the formation of random combinations or arrangements of chromosomes which brings about genetic variation.

Front 36

Describe the process of Fertilisation:

Back 36

Before fertilization occurs, the sperm is deposited in the vagina and swims past the cervix and uterus and into one of the oviducts. Here, they will locate and egg cell. Once one sperm makes contact with the zona pellucida of the egg cell the acrosome reaction occurs and digestive enzymes are released which digest the zona pellucida. The sperm then fuses with the cell membrane provoking the cortical reaction to occur; this is where the egg cell releases cortical granules in vesicles between the cell membrane and zona pellucida which causes the zona pellucida to thicken so other sperm cannot enter. Sperm nucleus enters cell and tail is left out. Now both fuse together forming a zygote.

Front 37

How does fertilization occur in flowering plants?

Back 37

1) a pollen grain lands on the stigma of a flower. The grain absorbs water and splits open. 2) a pollen tube grows out of the pollen grain down the style. Now, there are 3 nuclei present in the pollen tube -one tube nucleus at the tube's tip and 2 male nuclei trailing behind it. The tube nucleus leading the way releases enzymes which gives it way through the pollen tube. 3)when the tube reaches the ovary, it grows a micopyle and into the embryo sac in the ovule. 4) in the embryo sac, the tube nucleus disintegrates and the tip of the pollen tube bursts releasing the two male nuclei that were following it. One nucleus fuses with the egg nucleus to form a zygote which divides by mitosis to become the embryo of the seed. The second male nucleus fuses with 2 other polar nuclei which becomes the food store.

Front 38

What are unspecialized cells called?

Back 38

stem cells

Front 39

How do unspecialized cells become specialized and what is this process called?

Back 39

Process: Differentiation 1)stem cells all contain the same genes but not all are expressed as all of them are not active.2)Under the right conditions, some genes are activated and other genes are inactivated. 3) mRNA is only transcribed from the active genes. 4)the mRNA from the active genes is then translated into proteins. 5)these proteins modify the cell structure and control cell processes (activation of more genes) 6) changes to the cell produced by these proteins cause the cell to become specialized (differentiate). These changes are difficult to reverse, so once a cell has differentiated it stays specialized.

Front 40

How are red blood cells made?

Back 40

-they are produced from stem cells in the bone marrow. They contain a lot of hemoglobin and have no nucleus

-the stem cells which produces a new cell in which the genes for haemoglobin production are activated. Other genes involved in removing the nucleus are activated as well. Many genes are activated and inactivated resulting in a specialized blood cell.

Front 41

Where do stem cells first originate from in humans?

Back 41

in humans, stem cells are found in the embryo (here the differentiate into all the cells needed to form a fetus). Later onwards, in adults, they are found in bone marrow where they usually differentiate to form red blood cells.

Front 42

Define "potency":

Back 42

this is the ability for a cell to differentiate

Front 43

Define totipotency:

Back 43

the ability to produce all cell types including all specialized cells in an organism and extra embryonic cells (cells of the placenta and umbilical cord).

Front 44

Define pluripotency:

Back 44

the ability of a stem cell to produce all the specialized cells in an organism (but not extra embryonic cells)

Front 45

Describe stem cells in plants:

Back 45

plants have stem cells which are usually found in shoots and roots where it is still growing. All their stem cells are totipotent.

Front 46

Describe the use of stem cells in medicine:

Back 46

Because stem cells can develop to form any specialized cell, this could be used to replace damaged tissues by reconstruction for example, leukemia, where chemotherapy destroys all their stem cells in their bone marrow so they can have bone marrow transplants. Scientists had been researching ways to treat spinal cord injuries - stem cells used to treat nerve damage and heart disease. Overall, this can help save lives as stem cells can grow organs without waiting for a transplant. Also, they can improve the quality of life for the blind (stem cells used to replace damaged cells in eyes).

Front 47

Where can stem cells be obtained from adults?

Give one disadvantage

Back 47

-body tissues such as bone marrow (from areas such as the hip bone) but this can be quite painful.

-Disadvantage: aren't as flexible as embryonic cells as they can only develop to form certain type of cells.

Front 48

Where can embryonic stem cells be obtained?

Back 48

-these stem cells can be obtained from early embryos created by IVF which are cells that have been fertilized outside of the body.

-these embryos are only around 4-5 days old when the stem cells are removed.

-these stem cells can develop and specialize into any cell

Front 49

What are the ethical issues regarding obtaining stem cells from embryos?

Back 49

-many people believe that fertilization forms a unique individual that has the ability to become a person so it is wrong to kill embryos.

-some people disagree as the embryos are viable; they won't survive past a few days anyway if it was placed into the womb.

-some people believe adult stem cells should be used but they can only develop into a limited number of specialized cells.

Front 50

What common 5 jobs do Regulatory authorities have with stem cells?

Back 50

1) looking at proposals of research to decide if they should be allowed so that any research using embryos should be for good use with a decent reason and that it shouldn't be unnecessarily repeated.

2)licensing and monitoring centers involved in embryonic stem cell research ensuring that only fully-trained staff carry out this research so they won't waste resources like embryos avoiding unregulated research.3)producing guidelines and codes of practice so (similar ways of practice with scientists ensures that results can be compared). Methods of extraction controlled. 4)monitoring developments of scientific research so all guidelines are up to date. 5)provide information to governments and professionals which help promote the science involved in embryo research and helps society understand why its so important.

Front 51

Define continuous variation:

Back 51

this is when individuals in a population vary within a range. There are no distinct categories.

e.g height/weight

Front 52

Define discontinuous variation:

Back 52

this is when there are two or more distinct categories.

e.g sex/blood group

Front 53

What are characteristics controlled by one gene only called? And do they usually show discontinuous or continuous variation?

Back 53

monogenic

-discontinuous variation e.g blood group

Front 54

What are characteristics controlled by more than one gene only called? And do they usually show discontinuous or continuous variation?

Back 54

if they are controlled by different loci they are polygenic

-continuous variation e.g height

Front 55

What do you call the positions in which the same gene for different alleles are positioned?

Back 55

the locus

Front 56

Define phenotype

Back 56

the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Front 57

Define Genotype:

Back 57

the genetic makeup of an organism or group of organisms

Front 58

Give 4 examples of things that are influenced by our environment and genotype:

Back 58

-Height: tall parents will usually have tall children, but if they are malnourished they won't grow.

-Monamine Oxidase: an enzyme that breaks monamines; having low levels of this links to mental disorders. Its monogenetic.

-Cancer: uncontrollable division of cells; affected by genes but also diet and environmental factors.

-Animal hair colour: this is polygenetic but the environmental temperatures can cause it to change.

Front 59

Define niche:

Back 59

this is the role of a species within its habitat

this includes:

-the interactions it has with living organisms (what is eats and what eats it)

-its interactions with the non-living environment (e.g what it breathes in and out)

Front 60

What happens if two species try to compete for the same niche?

Back 60

they will compete with each other and one will be more successful than the other until only one of them is left behind.

Front 61

Give an example of two competing niches:

Back 61

Common pipistrelle bat:

this bat lives throughout Britain on farmlands, woodland, and hedgerows. It feeds on mosquitos using echolocation at 45kHz

Soprano pipistrelle bat:

bat lives on woodland close to rivers. Feeds by catching insects using echolocation at 55kHz

Front 62

What three ways can organisms be adapted to their niche?

Back 62

1) behavioural adaptations: this is the way the organism acts increasing it chance of survival. (bats make mating calls).

2)physiological adaptations: process inside the body of an organism increasing its chance of survival. (e.g low metabolism)

3)Anatomical adaptations: structural features which increase its chance of survival (e.g flexible, light wings).

Front 63

Describe how adaptations become more common by evolution.

Back 63

1)predation, disease and competition create a struggle for survival.

2)individuals with better adaptations survive giving them the ability to reproduce and pass on their characteristics to offspring.

3)over time, number of individuals with these characteristics duplicate.

4) this leads to evolution because favorable adaptations become more common in the population

Front 64

Use peppered moths as an example of natural selection:

Back 64

peppered moths show variation in colour - there are black and white ones. Before the 1800s there were more white moths than black but by the 1800s pollution had blackened many of the trees that the moths lived on so black moths were better at camouflaging from predators than white ones so they developed a higher survival rate so the number of black moths began to increase significantly.

Front 65

Define Taxonomy:

Back 65

this is the science of the classification in which organisms are named and organized into groups.

Front 66

List the order (6 groups) in which organisms are classified.

Back 66

1)Kingdoms |

2) Phylum |

3) Class |

4) Order |

5) Family |

6) Species |

\/ (KP-COFS)

Front 67

Define species:

Back 67

this is a group of similar organisms able to reproduce to give fertile offspring.

Front 68

What are the features and one example of Prokaryotae:

Back 68

e.g: bacteria

features: unicellular, no nucleus, size less than 5µm

Front 69

What are the features and one example of Protoctista:

Back 69

e.g algae, protozoa

features: eukaryotic cells, live in water, both single and multicellular

Front 70

What are the features and one example of Fungi:

Back 70

e.g yeasts, moulds, mushrooms

features: eukaryotic, chitin cell wall, saprotrophic (release enzymes and absorb nutrients from dead organisms)

Front 71

What are the features and one example of Plantae:

Back 71

e.g mosses, flowers

features: eukaryotic, multicellular, can photosynthesize, contain chlorophyll, autotrophic (produce their own food)

Front 72

What are the features and one example of Animalia:

Back 72

e.g mammals, molluscs

features: eukaryotic, multicellular, heterotrophic (consume plants and animals

Front 73

Define phylogeny:

Back 73

this is the study of the evolutionary history of groups of organisms. It tells us which species are related and how closely they are related.

Front 74

Define Molecular phylogeny:

Back 74

looks at molecules of DNA and proteins to see how closely related organisms are based on how similar their molecules appear to be.

Front 75

How does the new system classify organisms differently?

Back 75

before, an organism had to be classified under 1 of the five kingdoms but now... its classified under 3 main super kingdoms: Bacteria, Archaea, Eukarya. Fungi, plantae, animalia and protoctists are all under Eukarya meanwhile Prokaryotae are under both Archaea and Bacteria.

Front 76

Briefly (no need to reference to phospholipid bilayer) describe the structure of the cell wall and its function:

Back 76

the cell wall is a rigid structure that surrounds plant cells. Made mostly of carbohydrate cellulose.

Function: supports plant cells.

Front 77

Briefly describe the middle lamella and its function:

Back 77

this is the outermost layer of the cell

function: this layer acts as an adhesive sticking adjacent cells together giving the plant stability.

Front 78

Briefly describe the plasmodesmata and its function:

Back 78

channels in the cell walls that link adjacent cells together

function: allow transport of substances and communication between cells.

Front 79

Briefly describe pits and their function:

Back 79

regions of the cell where the wall is thinner and are arranged in pairs adjacently.

function: allow transport of substances between cells.

Front 80

Briefly describe chloroplasts

Back 80

a small flattened structure which is surrounded by a double membrane and as membranes inside called the thykaloid membranes which are stacked up to form grana which are linked together by lamellae - thin, flat pieces of the thykaloid membrane

-function: contais chloroplasts site of photosynthesis. which happen in the grand and stroma (fluid around chloroplasts)

Front 81

Describe the function of chloroplasts:

Back 81

-function: contais chloroplasts site of photosynthesis which happens in the grana and stroma (fluid around chloroplasts)

Front 82

Describe the structure and function of amyloplasts:

Back 82

a small organelle enclosed by membrane which contains starch granules

function: stores starch grains and convert starch back into glucose when the plant requires it.

Front 83

Describe the structure and function of the vacuole:

Back 83

the vacuole is a compartment surrounded by a membrane called the tonoplast.

function: vacuole contains cell sap which is made up of water, enzymes and minerals, and waste products. They keep the cell turgid. Involved in isolation and breakdown of unwanted chemicals.

Front 84

Describe Xylem vessels:

Back 84

the function of xylem vessels is to transport water and mineral ions up the plant and provide support. Very long, tube-like structures made from dead cells found together in bundles. They are longer than they are wide and have hollow lumen. Have no end walls or cytoplasm. Have an uninterrupted tube allowing water to flow through. Walls are thickened with lignin for support - water moves in where there is no lignin. These are usually found in centre of stem -forming vascular bundles.

Front 85

Describe the structure and function of Sclerenchyma fibres:

Back 85

their function is to provide support.

-they are made up of bundles of dead cells that run vertically up the stem (like Xylem).

-the cells are longer than they are wide

-hollow lumen

-cell walls thickened with woody lignin along with cellulose

-associated with vascular bundles.

Front 86

Describe the structure of Starch:

Back 86

starch is used by plants to store glucose; it is made up of two polysaccharides called amylose and amylopectin (amylose is unbranched alpha glucose so it gives it a coiled structure which makes it compact and suitable for storage and amylopectin is branched alpha glucose which allows enzymes to break it down quicker.

-starch is insoluble in water so so water doesn't enter by osmosis which makes it good for storage.

Front 87

Describe the structure of Cellulose:

Back 87

-is made of long, unbranched chains of beta-glucose joined by glycosidic bonds.

-the glycosidic bonds are straight so the cellulose chains are also straight.

-the individual cellulose chains are linked together by hydrogen bonds to form microfibrils which provides structural support for the cell.

Front 88

How come plant fibres are so strong?

Back 88

-the cell wall contains cellulose microfibrils in a net-like arrangement which strengthens the fibres.

-also, in some structural plant cells like sclerenchyma, secondary cell walls between the normal cell wall and membrane are present which is thicker and has more lignin. The process of the growth of a secondary cell wall is called secondary thickening. This makes it stronger.

Front 89

What experiment would conduct to measure the strength of plant fibres:

Back 89

1)attach the fibre to a clamp stand and hang a weight from the other end.

2)Keep adding weights one at a time until fibre breaks.

3)Record mass needed to break fibre.

4)repeat experiment with different fibres to increase reliability using the same length

5)variables such as temperature/humidity most be kept constant.

6)wear goggles and protect feet from heavy weights.

Front 90

Define Sustainability:

Back 90

this is about using resources in a way that meets the needs of the present generation without harming future generations (e.g using renewable resources)

Front 91

Give example of stainable and unsustainable practices:

Back 91

sustainable: using renewable resources. Planting trees after each one is cut down.

unsustainable: using nonrenewable resources, for e.g making oil-based plastics like polyethene from fossil fuels.

Front 92

What are the advantages of using plant fibres while contributing to sustainability vs. using oil-based resources:

Back 92

-ropes and fibres can be made out of plants

-less fossil fuels are used this way and maintain supply for future generations

-products from plant fibres are biodegradable

plants are easier to grow and process; they are also cheaper than making them out of fossil fuels

Front 93

How can starch be used to contribute to sustainability and what are its advantages:

Back 93

-starch is found in all plants

-plastics are made from oil but some can be made from starch; these are called bioplastics

-are more sustainable as they can be regrown

-use to make fuel bioethanol for vehichles

Front 94

Why do plants require the following:

Water

Magnesium ions

Nitrate ions

Calcium ions

Back 94

Water: photosynthesis

Magnesium: production of chlorophyll

Nitrate: production of DNA, proteins, plant growth, fruit production, seed production.

Calcium: plant cell walls and plant growth

Front 95

EXPERIMENT ON

Investigating plant mineral deficiencies:

Back 95

1)take 30 seedlings of the same plant (same age and height) and plant them in separate pots.

2)Make up 3 nutrient broths varying the concentration of calcium ions. Make 3: each should have a high, medium and low concentration. 4) each should have only one of the 3 broths. 5)record plants after 7 weeks and calculate average height.

6)make sure all variables such as amount of sunlight, water, temp are kept constant!

Front 96

Use William Withering's discovery to explain the way drugs were first made:

Back 96

Willaim W, born in the 1700s discovered that an extract of foxgloves could treat dropsy (swelling provoked from heart failure). The extract contained the drug digitalis. He made a chance observation where one patient was actually treated using foxgloves. The thing is, is that the drug digitalis can be very harmful if too much is taken and has no effect if too little is taken therefore, Withering went through trial and error to come with the most suitable concentration.

Front 97

What are modern drug testings like nowadays:

Back 97

-they are much more controlled - before, people were used as live subjects but now computers can be used to model potential effects. -tested on live animals before clinical trials are run on humans -Go through 3 phases: phase 1 --> test drug on small group of healthy people to see what the safe dosage is and if there are any side effects. phase 2---> tested on a larger group of patients to see how well it works. phase 3----> drug is compared to existing treatments testing hundreds and thousands of patients comparing previous and new treatments to see which works better.

Front 98

Name two ways you can make clinical trials more reliable:

Back 98

-Placebos: this can be used in phase two when dividing two groups to see if the placebo (a sugar-pill which isn't real) brings about the placebo effect in patients where they get better just because they 'believe' it works or if the actual drug does the work.

-Double blind study: phase 2 and 3 involve neither patients or doctors being aware that the drug is a placebo. This reduces bias.

Front 99

EXPERIMENT ON

effect of antimicrobial properties of plants:

Back 99

1) take extracts from plants that you want to test first by drying and grinding each piece then soak in ethanol. Make sure extracts are the same size.2)filter off liquid. 3)spread some bacteria on agar plate. 4)Dip discs of absorbent paper in the extracts (should be same size). 5)use also control disc dipped only in ethanol without the extract. 6) Place discs on agar plate. Incubate plate to allow growth. 7) areas around discs with no bacteria is called the inhibition zone. 8) size of inhibition zone tells us the strength of the antibacterial properties of the plant in terms of effectiveness.

Front 100

Define Biodiversity:

Back 100

this is the variety of living organisms in an area; there are 2 types of diversity:

-Species Diversity: the # of different species and their abundance in each area.

-Genetic Diversity: the variation of alleles within a species e.g blood type is determined by 4 different alleles!

Front 101

Define Conservation:

Back 101

this is needed to maintain a biodiversity especially those who are about to become extinct and are endangered so they need to be protected.

Front 102

Describe Endemism and give an example:

Back 102

this is when a species is unique to a single place.

e.g: the giant tortoise in Galapagos Islands

Front 103

Why is conservation important in the case of endemic species?

Back 103

it is especially important to endemic species because they are vulnerable to extinction and numbers usually decline.

Front 104

How is the species diversity measured in a habitat?

Back 104

1) count the number of different species in an area. The number of different species is called species richness. (The higher the number of species, the greater the species richness but does not show the abundance of each species.)

2)count the number of different species and the # number of individuals in each specie then use a biodiversity index to calculate the species diversity.

Front 105

What are the drawbacks of measuring species diversity in habitats by counting; what is an alternative method?

Back 105

it is too time consuming. Instead, we could choose a sample -- a small area in the habitat to be studied. To avoid bias, this area should be completely random. Divide the field using a grid. Count the number of individuals:

plants----> quadrants. flying insects-->sweepnets ground insects---> pitfall trap

aquatic animals ---> net, repeat multiple times using same technique and estimate for the species richness.

Front 106

How can the genetic diversity within a specie be measured and why do they differ?

Back 106

Individuals of the same specie vary because they have different alleles therefore genetic diversity is the variety of alleles in the gene pool (population) of a species. The greater the variety of the alleles the greater the genetic diversity. Genetic diversity can be investigated in two ways: using phenotypes and genotypes. Phenotypes describe the observable characteristics of an organism (e.g eye colour) whereas genotypes do the opposite.

Front 107

CONT (of genetic diversity)

Back 107

Just by looking at different organisms of the same specie we can get an idea of its genetic diversity - more variety means more genetic diversity. Using genotypes, we can measure the number of different alleles a species has for one characteristic to see how genetically diverse the species it.

Front 108

What will happen is there is an extinction of a particular specie?

Back 108

there will be a loss of genetic diversity within a species therefore, a loss in global diversity.

Front 109

Give one way of conserving plants and evaluate this method of conservation:

Back 109

Using seedbanks which store lots of seeds from lots of different species of plant by storing the seeds of endangered plants. This is done by keeping them in a cool, and dry place so that they can be stored for a long time. Also, they need to be tested for viability (the ability to actually grow into new plants) - we don't want dead seeds! Adv: cheaper to store seeds than fully grown plants. -large numbers of seeds can be stored. -less labour than plants.

Front 110

CONT (methods of conservation)

Back 110

Dis:testing seeds for viability can be time consuming. -can be expensive to store all types of seeds and regularly test them for viability. -may be difficult to collect seeds from some plants as they are in remote locations.

Front 111

Give one way of conserving animals and evaluate this method of conservation:

Back 111

captive breeding programmes: this involves breeding animals in controlled environments like zoos. Endangered species can be bred together in zoos to increase their numbers because their numbers are critically low in the wild. However, some animals have problems breeding in zoos than they do in the wild so doing this could make it worse. Also, some people think that it is cruel to keep animals isolated from their normal environment.

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What are the advantages and disadvantages of reintroducing organisms from zoos and seed banks to the wild?

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Adv: can increase numbers in the wild which restores global diversity.

Adv: help predators that rely on these plants or animals for food as part of their habitat

Dis: reintroducing them could also mean the formation of new diseases to habitats harming organisms that share the same environment.

Dis:may have problems finding food or communicating as they were not raised in the wild.

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How do seedbanks contribute to scientific research? Give some advantages and disadvantages:

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Seedbanks:

-scientists study how plant species can be successfully regrown from seeds

-can be used to grow endangered plants for use in medical research

-dis: studying plants from seeds in a seedbank cannot be generalized to other wild plants.

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How do zoos contribute to scientific research?

Give some advantages and disadvantages:

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-increases knowledge about the behavior, physiology and nutritional needs of animals which can be contributed to conserve animals in the wild correctly.

-zoos can carry out research that wouldn't be possible in the wild.

-dis: animals in isolation may have behavioral differences than those in the wild.

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How do zoos and seed banks help educate people about endangered species and what does this affect?

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it raises public awareness so that people when people actually get to see the endangered animals or plants, they may become more enthusiastic about conservation work. And seed banks contribute to providing training and setting up other local seed banks around the world.