Category: Year13 Biology

Homemade Ginger Beer
(Makes 4 x 1.25 litre bottles)

Yeast Mixture
 1 teaspoon dried yeast (not Surebake type)
 1 tablespoon sugar
 1 cup warm water

Ginger Beer
 2 cups sugar
 2 tablespoons ground ginger
 1 teaspoon tartaric acid
 2 litres hot water juice and grated rind of 2 lemons
 2 litres cold water

Stir the yeast mixture ingredients together in a small bowl or cup and leave to stand for 10 minutes.
1. Place the sugar, ginger, and tartaric acid in a clean bucket.
2. Pour in the hot water and lemon juice, and stir to dissolve the sugar.
3. Add the cold water, cool to lukewarm, and add the yeast.
4. Leave in the bucket (covered with a towel) for 24 to 36 hours.
5. Strain into 4 thoroughly clean 1.25 litre softdrink bottles.
6. Fill the bottle to within 5cm of the top with extra cold water.
7. Put 1 teaspoon of sugar in each bottle and screw on washed tops.
8. Shake to dissolve the sugar.
9. Leave the bottles to stand in a warm place until they feel absolutely rigid when squeezed (this takes between 2 to 5 days to happen) then refrigerate. If the bottles are fizzy, loosen then tighten the lids several times. Consume within 2 to 3 weeks.

구제역의 의학명은 Aphtae epizooticae이다.  구제역의 common name은 입발굽병 (Foot and Mouth Disease)이다. 소나 돼지등 가축에 대한 전염성이 높은 급성(acute) 바이러스성 전염병의 하나다. 사람에게 영향을 끼치지 않는걸로 알려져 있고, 별 다른 치료를 하지 않는다.  구제역은 세계 대부분의 지역에서 발생한다. 사슴, 염소, 양, 소, 코끼리, 쥐, 고슴도치 등도 감염될 수 있고 이런 동물들이 돌아다니면서 전염시킬 수 있기 때문에 구제역이 발생하지 않던 곳에서도 갑자기 발생할 수 있다.

1897년에 프리드리히 뢰플러가 구제역의 원인은 바이러스라는 것을 발견하였다. 감염된 동물혈액을 필터에 통과시켜도 여전히 다른동물을 감염시킬 수 있을정도로 작은 바이러스 임을 확인했다.

감염된 가축은 3일도안 고열에 시달린다. 입과 발굽주변에 물집이 생기는데 입으로 거품이 많고 끈적끈적한 침을 심하게 흘린다. 발굽에서도 열과 상처가 생겨 걸음을 절뚝거린다. 체중감소를 보이기도 하며 젖소의 경우 우유생산량이 감소한다. 어린 가축의 경우 심장에 문제가 생기겨 죽기도한다.

대한민국 전역에서 구제역에 걸린 동물들을 매장하여 처분하는 가운데 동물의 배를 가르는 일등 작업에 동원된 공무원들이 스트레스 장애에 시달리고 있다. 소와 돼지의 배를 가르지 않고 묻을 경우 땅속에서 동물배에 있는 가스가 땅속에 차서 폭발이 일어날 수 도 있다. 이 작업에 동원된 사람중 대부분이 소와 돼지가 죽기전 모습이 잊혀지지 않는다며 괴로워하며 고통을 호소하고 있다.

Question

Discuss the reasons why it is often impossible or more difficult to use bacteria as transgenic organisms to make many human proteins.

Answer

Many human genes are very large, with many intron regions in the gene. Bacterial DNA does not contain introns and amount of DNA which can be inserted is limited.

Introns would have to be removed from human gene to make it small enough to fit into the plasmid. Protein required may need further processing beyond assembly of amino acids. Bacterial cells do not have machinery to carry out secondary and tertiary processes in creating a complex protein.

Question

Research is involved in the production of transgenic plants to incorporate characteristics which make some of the very rare plants hardier to a wider range of conditions. Many of the medicinal plants are dicotyledonous, which means that Agrobacterium can be used as a vector in the production of these transgenic plants.

Describe why these plants are called transgenic plants and explain the human need and demand which is driving this research. Discuss the scientific basis for concerns which some groups have for the production of such transgenic organisms.

Transgenic plants contain introduced genes artificially from another species or additional gene which is not part of it’s original genome. Human need and demand driving research is people in third countries need the plants to maintain health – not enoufh plants are left and they are in risk of becoming extinct, cutting off this resource for these people.

Traditional breeding processes are very slow and seeds may not grow in areas where the plants are needed. New plants creased to meet specific need using genes from other or similar species to create chracteristics desired for growing purposes.

Concerns

Creation of super weeds by making weedkiller-resistant varieties, cross breeding with vigorous closely related weed species could allow genes to be transfered.

Using the R genes as markers in the bacterial vectors could lead to transfer of resistance within bacterial species by transformation. It will create antibiotic resistance in super bug.

Cross pollination with wild relatives will destroy the wild genome.

Question

Forensic scientists often use PCR before they carry out DNA profiling. Discuss the human need and demand for this process, its particular usefulness in forensic science and how scientists have to ensure that the evidence is admissible in court.

Procedure can begin with only a minute amount of DNA- DNA can be obtained from a crime scene from myriad of sources and only small amounts required. Contamination of DNA from any sources must be restricted or accounted for, since contaminant will also be multiplied/replicated.

Question

Discuss how DNA profiling can be used to help scientists study the mating and breeding of the blue duck.

Answer

To avoid inbreeding, scientists would ensure mating between genetically unrelated individuals – increasing gene pool, reduces change of expression of deleterious/lethal genes. By identifying DNA profiles, most successful adult breeders can be identified (their offspring will carry successful breeders’ DNA markers) – scientists would preferentially use these birds to build species numbers.

Question

Female salmon prefer the biggest male as a breeding partner. Discuss how this preference would affected the spread of the growth gene through a wild salmon population if genetically modified salmon were accidentally released.

Answer

Genetically modified male salmon have same survivorship chances and same reproductive success as wild salmon. Females will not necessarily choose only GM salmon, as not all would be the ‘biggest’. Of those chosen, the genes for increased growth would spread rapidly through population, since those males carrying increased growth genes reach maturity quicker and thus have less exposure to predation, disease etc..

GM salmon have same fitness and reproductive sucess as non-GMsalmon and females equally choose GM salmon and non-GM salmon based on size.

Question

Some inherited genetic diseases were caused by the lack of an essential protein. Biotechnology may be used to treat individuals affected by these genetic diseases. Research into genetic diseases caused by the lack of an essential protein can focus on using biotechnology in two ways:

1. Produce the protein cheaply and affectively using microorganisms so that the patient can be regularly dosed with the protein.

2. Cure the affected person by inserting functioning genes so that the person is capable of producing the required protein.

Discuss difficulties that could occur when delivering a gene into a patient. These are things that researchers would need to consider, and check for, and ensure were not a problem before the patient could be said to be ‘cured’ and able to produce their own essential protein.

Answer

A faulty gene is isolated and replaced by a healthy/active gene. Isolation of gene of interest inserted into DNA of a suitable vector using vector using restriction enzymes and ligation and then cloned. Correct gene delivered back into the human, enabling coding of required protein.

Problems may arise with type of vector used, immune system may attack it/ may elicit an allergic response. Testing is needed to make sure the gene delivered works to correct cells and is incorporated into nucleus for protein synthesis. The quantity of protein made would have to be sufficient to effect a cure – needed to deliver enough gene to do this and genes must remain in patient long enough to have an effect.

Question Two

Discuss why the procedures used to ‘sex’ the bones of the Moa were harder than just identifying that they belonged to the same species. In your discussion, say why procedures were needed and why the researchers used DNA from closely related living birds for comparison.

Answer

The species can be identified using the mitochondrial DNA in cells. The karytype of living species of related birds is known and can be used to identify sex of Moa bones were from. Sex chromosome is need to identify the sex of Moa.

However, there are more mitochondria/mitochondrial DNA in cells compared to chromosomes/nuclear/sex chromosome DNA because there is only one of them in a cell. This is the reason why the ‘sex’ of the Moa is harder to identify.

Question one

The Wollemi pines have been shown to be susceptible to the die back fungus(Phytophythora cinnamomi) that attacks trees in other Australian native forests. One species of pine has resistance to this fungus because of a single gene. Discuss how biotechnological technique could be used to develop Wollemi pines that are resistant to the die-back fungus. In your discussion, include that may result from the procedures involved.

Answer

Wollemi pines could be made resistant to die-back fungus using process of transgenesis  – taking organism resistant to fungus, identify resistant gene, cut using restricti

on enzymes, cut plasmid to infect pine.

Concerns

Gene product may interact with products of another gene, transfer process may disrupt ability for gene to offer resistance, gene may insert in middle of a vital Wollemi pine gene and disrupt ability of that gene to function (produce non functional protein), gene may only function sporadically because not inserted into a chromosome therefore disrupting its ability to offer resistance.