Chapter 31 - Genetic engineering

Question 1

Define genetic engineering

Answer 1

Direct manipulation of an organisms genetic material.

Question 2

Name three processes of genetic engineering

Answer 2

• Insertion of genes
• Alteration of genes
• Deactivation of genes

Question 3

Describe the principles of using a vector in GE

Answer 3

• Chromosome or locus containing the gene is identified and isolated
• Restriction enzyme is used to cut DNA into segments and remove the required gene
• A bacterium of fungus is used
• Plasmids are removed from bacterium or fungus
• Plasmids cut open to form a strand
• Removed gene is inserted to form recombinant DNA
• Ligase used to join Recombinant DNA into a plasmid again
• Plasmid inserted back into host cell
• The bacterium reproduces by mitosis

Question 4

Advantages of using artifically produced insulin

Answer 4

• Cheaper to extract and purify
• Identical to human insulin
• No allergic reactions occur
• Constant supply available
• The body shows a more rapid response to the hormone

Question 5

Advantages of using genetically manipulated crops

Answer 5

• Can be modified to produce natural insecticides
• Can be herbicide resistant
• More draught resistance
• Increased nutritive quality
• Increased crop yield

Question 6

Describe the goal of the human genome project

Answer 6

• To map the entire DNA base sequence of every chromosome in the human genotype
• Identify all genes in the human DNA sequence
• Working out the nucleotides in each gene
• Determining what each gene codes for
• To determine the precise role of each gene

Question 7

How is the human genome project utilised in the modern world?

Answer 7

Satisfies the human quest for knowledge
Identifying genes causing genetic diseases
Imroved treatment of genetic diseases
Prevention of genetic diseases

Question 8

Potential problems with irresponsible GE

Answer 8

• Transferred genes may have an effect on consumers, causing genetic disorders
• Unwanted genes may cause resistance in weeds to weed killers
• New extremely dangerous pathogens could be created accidentally
• Increased antibiotic resistance in bacteria

Question 9

Define variation

Answer 9

• Differences existing in a species

- Result from mutations or environmental factors

Question 10

Continuous variation

Answer 10

• Smooth gradation between individuals
• Caused by genetic and environmental factors
• No distinct catagories
• Height, skin colour, nose shape, etc

Question 11

Discontinous variation

Answer 11

• Extremes
• You have a characteristic or you don’t
• Genetic ONLY
• Blood groups, gender, etc

Question 12

Genetic variation

Answer 12

• Inheritable
• Involves different alleles
• Random fusion of gametes
• Mutations produce new alleles

Question 13

Environmental variation

Answer 13

• Non-inheritable

- Acquired characteristics from environment (scars, hair lenght, etc)

Question 14

Define a genetic mutation

Answer 14

The sequence of bases is not completely copied during replication. Change in instructions for protein synthesis occurs.
Faulty proteins or no proteins at all (cause of albinism) occurs

Question 15

Define a mutagen

Answer 15

Factors increasing mutation chances

Also increases the rate at which mutations occur

Question 16

Define natrual selection

Answer 16

• Variations occuring among individuals in a population to give those individuals a better chance of survival. Strongest survive, interbreed. Offspring receive favourable alleles.

Question 17

Describe evolution

Answer 17

All organisms descend from common ancestors. Populations modify in response to environmental changes. These changes occur over millions of years.

Question 18

Now. Explain how natural selection leads to evolution. It’s not that hard. Use logic.

Answer 18

• Individuals in a population have reproductive potential
• Many fail to survive and die
• Many fail to reproduce
• This occurs due to environmental factors
• Those best adapted to survive pass on their alleles to offspring. Variation occurs and phenotypes gradually change.
• Gene pools change.
• Over time, this leads to evolutionary changes.
• After many years, a new species may arise.

Question 19

Sickle cell anaemia is a recessive gene. So what happens in the Heterozygous state? (Refer to malaria)

Answer 19

The person will NOT have sickle cell anaemia, but is LESS likely to suffer from malaria

Question 20

What are antibiotics?

Answer 20

Substances used in medicines that destroy disease causing bacteria

• Earliest antibiotic is called penicillin, produced from a fungus
• Many diseases can be successfully treated by antibiotics

Question 21

What is the effect of antibiotics on bacterium cells?

Answer 21

Antibiotics cause the cell walls of bacteria cells to become weaker during production. The pressure inside the cell can not be contained and the bacterium cell bursts and dies.

Question 22

Why do antibiotics NOT effect virusses?

Answer 22

Well… Let’s see. First off, virusses are NON-LIVING and therefore they cannot DIE. Virusses are non-cellular, have not cytoplasm and cell walls, and no cellular pressure, and cannot burst.

Question 23

So antibiotic-resistant bacteria is now a huge problem. What is this?

Answer 23

• Antibiotics are widely misused
• Patients do not complete antibiotic courses
• They stop taking antibiotics when they start feeling better (idiots)
• A partial course only kills weak bacteria
• Natural selection occurs. Strong bacteria mutute and develop a resistance against the antibiotics, and the offspring inherits this trait.
• Well done, you have now infested your body with a super-incurable bacterium cell. Dit sal jou leer.

Question 24

How do we prevent antibiotic resistance?

Answer 24

• Antibiotics should be used sparingly
• Courses must be completed
• Reduce the need for antibiotcs by improving health and living conditions

Question 25

Now will follow an explination of how bacterium cells develop resistance due to SELECTIVE PRESSURE. Pay close attention to all the different terms used.

Answer 25

- Antibiotic resistance is natural selection - Antibiotics place selective pressure on bacterium cells - Alleles providing no resistance will disappear from the population - Resistant allele passed on to offspring The frequency of this allele increases - The strongest cells survive - More advantages phenotypes are now passed on more frequently

Question 26

How does artificial selection and the production of a variety of plants and animals affect the economy?

Answer 26

- Artificial selection used to create breeds which cannot occur naturally - Many organisms are genetically modified by humans - Leads to desirable characteristics - Best organisms are chosen to produce the next generation, while worse organisms are not allowed to breed - Leads to high milk production, high yield, resistance to drought in the respective organisms - Therefore, artificially selected animals and plants can boost an economy.

Question 27

Name some advantages artificial selection brings about, concerning crops

Answer 27

- Climate adapted crops - Disease resistant crops - High yielding crops - More nutritious crops

Question 28

Name some advantages artificial selection brings about, concerning cattle

Answer 28

- Disease resistant cattle | - Cattle produce more milk and/or meat

Question 29

State the importance of maintaining a gene bank and rare breeds

Answer 29

- Gene banks are collections of different breeds and wild relatives of domesticated strains - A plant gene bank includes a collection of seeds or tissue cultures - Seeds may contain different genes - Which can be bred into desirable crops when required - Can be used for genetic engineering

Question 30

Examples of animal gene banks

Answer 30

- Cold storage of sperm, eggs or embryos - Rare breeds can be conserved - Zoos and nature reserves where animals are protected also serves as a gene bank - Whole ecosystems are conserved