ch 8+9.1

Question 1

recombinant DNA technology

Answer 1

The procedures used to produce recombinant DNA, involving introducing DNA into a cell from a different type of organism or DNA that has been modified in some way. Also known as genetic engineering.

Question 2

genetically modified organism

Answer 2

Answer: An organism produced by genetic engineering.

Question 3

An organism that has had DNA from another species introduced into it artificially.

Answer 3

transgenic organism

Question 4

vector

Answer 4

A bacterial plasmid, viral phage or other such agent used to transfer genetic material from one cell to another.

Question 5

plasmid

Answer 5

In a bacterial cell, small circular strands of DNA distinct form the main bacterial genome; composed of only a few genes and able to replicate independently within cells.

Question 6

Describe the function of:
a restriction enzymes

Answer 6

Restriction enzymes cut strands of DNA at a specific sequence of nucleotides.

Question 7

Describe the function of:
DNA ligase.

Answer 7

DNA ligase is an enzyme capable of combining two small components of single-strand DNA into one single structure.

Question 8

What vector is used in the production of insulin by recombinant DNA technology?
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Answer 8

Answer: A plasmid. Circular strands of DNA distinct from the main bacterial genome.

Question 9

Explain how recombinant DNA technology is used to produce a vaccine for hepatitis B.

Answer 9

The gene for the surface antigen on the virus is isolated and added to the plasmid. The plasmid is introduced into a yeast cell. When the yeast cell divides, the new cells also contain the plasmid with the gene for the antigen. This gene allows the yeast cells to produce the antigen protein, which can be collected and purified.

Question 10

Artificial breeding

Answer 10

Artificial breeding

Selection of characteristic:
Selecting which male and female organisms to breed

Isolation of the gene:
If desired traits are bred, there is an increased chance of the gene being passed on

Incidence in the next generation
Able to increase or decrease the incidence of certain genes

Efficiency
Low efficiency

Question 11

Genetic engineering

selection…isolation….incidence….efficient

Answer 11

Selection of characteristic:
Identifying the organisms with the desired characteristic

Isolation of the gene:
DNA is added or removed from the genome

Incidence in the next generation
Able to increase or decrease the incidence of certain genes

Efficiency
high efficiency

Question 12

Explain why it is possible for an organism of one species to use a gene from another species to produce a protein.

Answer 12

It is possible if the gene from one species is spliced into the genome of the other species. This is recombinant DNA and the organisms is a genetically modified organism (GMO). The GMO will produce the protein from the introduced gene.

Question 13

Explain the importance of complementary bases with respect to inserting a fragment of DNA into a vector.

Answer 13

Complimentary bases will allow hydrogen bonds to form between the DNA fragment and the vectors genome. DNA Ligase is then able to join the backbone of each strand. If the bases were not complimentary then the splicing and uptake of the inserted gene would not be successful.

Question 14

Define ‘hyperglycaemia’ and explain why a lack of insulin results in this condition.

Answer 14

Hyperglycaemia is a condition where a person has abnormally high blood glucose levels. Insulin normally acts to bring down blood glucose levels, so a lack of insulin will result in higher than normal blood glucose.

Question 15

What causes type 1 diabetes?

Answer 15

Answer: Type 1 diabetes is an autoimmune disease where the person’s immune system destroys beta cells in the Islets of Langerhans in the pancreas.

Question 16

List the symptoms of hyperthyroidism.

Answer 16

Answer: Rapid heartbeat, weight loss, increased appetite, fatigue, sweating, anxiety and protruding eyeballs (Grave’s disease)

Question 17

Explain why goitre occurs.

Answer 17

Answer: If there is a lack of iodine in the diet, the thyroid gland becomes enlarged in an effort to increase hormone production.

Question 18

Explain why iodine supplements are used to treat some forms of hypothyroidism.

Answer 18

Answer: Thyroxine molecule contains four iodine molecules, and a tri-iodothyronine molecule contains three iodine molecules. If there is a lack of iodine in the diet, the thyroid gland is unable to make enough hormones, resulting in hypothyroidism

Question 19

Define ‘gene therapy’, and give an example of its possible use.

Answer 19

Answer: Gene therapy is the replacement of faulty genes with healthy genes. Research is currently concentrating on single-gene disorders such as cystic fibrosis, Huntington’s disease, muscular dystrophy and sickle-cell anaemia.

Question 20

List three ways that gene therapy could possibly correct faulty genes.

Answer 20

Answer:
• Replacing a mutated gene with a healthy copy
• Fixing or inactivating mutated gens
• Inserting a new gene that will fight the disease
• Making the immune system recognise diseased cells.

Question 21

Explain why it is important to diagnose cystic fibrosis at infancy.

Answer 21

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Answer: Early diagnosis will allow a low-fat, high-carbohydrate and high-protein diet to be established. This will allow CF parents to keep their child as healthy as possible and to delay or prevent serious lifelong health problems related to CF.

Question 22

Why is it possible that cell replacement therapy could be used to treat patients with Alzheimer’s or Parkinson’s disease?

Answer 22

Answer: Alzheimer’s disease is a progressive disorder that causes brain cells to degenerate and die. This results in a loss of brain volume, memory loss and dementia. Current treatment includes acetylcholine drugs, or drugs that inhibit acetylcholinesterase. Cell replacement therapy could be used to replace the brain cells lost to Alzheimer’s and to produce acetylcholine within the body.
Parkinson’s disease is a progressive, degenerative neurological condition that affects the control of body movements. It is caused by the death of neurons that produce dopamine in the brain. Cell replacement therapy could be used to replace the neurons lost, and to produce the required level of dopamine in the brain.

Question 23

Discuss why gene therapy for type 1 diabetes is focused on introducing the gene into alpha cells.

Answer 23

Answer: Type 1 diabetes is caused by an autoimmune disease that destroys beta cells in the pancreas. Gene therapy is used to reprogram the alpha cells to produce insulin as alpha cells are not damaged by the autoimmune disease.

Question 24

Tissue engineering utilises a scaffold for the tissues to grow on. Explain why this is necessary, and why it needs to be biodegradable.

Answer 24

Answer: The scaffold is required to generate a three-dimensional tissue. The scaffold serves as a template for tissue growth and can allow for diffusion of nutrients and to encourage cells to grow at the same rate and size. They need to be biodegradable so they can be absorbed by the surrounding tissue and not have to be surgically removed.

Question 25

Chromosomal Mutations

Answer 25

DELETION- part of chromosome is lost
DUPLICATION- Section of chromosome occurs twice
INVERSION – part breaks off and rejoins wrong way around.
TRANSLOCATION- part of chromosome breaks off and rejoins wrong chromosome
NONDYSJUNCTION- during meiosis a chromosome pair does not separate so one daughter cell has one less and one has one more (aneuoloidy)

Question 26

gene mutations

Answer 26

deletion
insertion
substitutions

Question 27

Cystic fibros

symptoms
cause
treatmens

Answer 27

genetic disorder
thick sticky mu\cos secreted by mucos glands
traps bacteria making them seseptible to infection
lung damage
pancreas also affected preventing enzymes for digestion

low fat high carb and protein

gene therapy

inherited ressesive allele

Question 28

different types of mutations

Answer 28

missense- change in amino acid, change in protein produced
nonsense- change in base sequence to the code stops, so shorter protein is produced unable to function
neutral- change in amino acid but is of the same type so the structure will not change enough to change protein
silent- do not cause a change in amino acid so no change

Question 29

gene mutations 2

Answer 29

duchenne muscular dystrophy
cystic fibrosis

Question 30

chromosomal mutations

Answer 30

down
patau
klinefelter

criduchat
Turner syndrome

Question 31

patau syndrome
chromosome
symptoms

Answer 31

partial trisomy extra chromo 13
intellectual disability and\ ectra finger on each hand
cleft palate
80%die within a month of birth

Question 32

klinefelter

Answer 32

sex chromo xxy
normal as boys then develop as adults
small testes no sperm, noobs sometimes intellectually disabled

Question 33

Turner syndrome

Answer 33

sex chromosome x monosomy

short stature lack sexual characteristics and infertile

Question 34

lethal recessive

Answer 34

tay sachs

disorder of lipid metabolism thats is inherited ina autosomal recessive pattern
mutation of hexa gene that codes for enzyme beta h (breaks down toxic substances in brain and spinal chord

the accumulation of gm2 gangoslide detrys neurons

deaty early childhood

Question 35

Explain how errors in DNA replication and cell division can result in mutations and give an example of a condition caused by each of these types of mutations. (4 marks)

Answer 35

DNA replication
The double helix unwinds and copies of the two strands are made but a deletion / insertion / inversion / translocation / substitution occurs which alters the sequence
Albinism / Duchenne muscular dystrophy / Tay Sachs / cystic fibrosis / other acceptable answers
Cell division
Homologous chromosomes fail to separate / non-disjunction occurs
Down syndrome / Klinefelter’s syndrome / Turners syndrome / other acceptable answers

Question 36

Suggest how mutations affect the process of natural selection.

Answer 36

Mutations contribute to variation in the gene pool of the population
Which allows some organisms to be offered a survival advantage
Or reduces their chances of survival
When conditions change / when selection pressures are different

Question 37

(g) Explain the relationship between carbon dioxide concentration and blood pH.

Answer 37

Carbon dioxide combines with water to form carbonic acid
Which breaks down to form hydrogen ions and bicarbonate ions
Carbon dioxide is carried in the blood as bicarbonate ions
Hydrogen ions determine blood pH