Variance, Selective breeding, Genetic Engineering, and Cloning

Question 1

What is an phenotype ?

Answer 1

Phenotype is the observable physical properties of an

organism

Question 2

Examples of phenotype…

Answer 2

This includes appearance, development, behaviour and even functioning of internal systems

For example, feather colour in birds is a phenotype

Question 3

What is phenotype depended on ?

Answer 3

Phenotype is depended on both genotype and

the environment

Question 4

What is genotype depended on ?

Answer 4

Genotype is the genes inherited by an

organism

Question 5

Every organism’s genotype is….

Answer 5

Every organism’s genotype is unique,

except identical twins and clones

Question 6

What is the environment ?

Answer 6

Environment is the habitat around you
- For example, flamingos are pink
because of pigments in their food

Question 7

What is Genetic variance ?

Answer 7

Genetic variance refers to the natural
differences in the genotype of a
population of a species

Question 8

Name the two types of genetic variance

Answer 8

There are two types of genetic variance:

• continuous like height
• dis-continuous, like eye colour

Question 9

What is a genetic difference due to ?

Answer 9

Genetic differences are due to

random mutations

Question 10

Do mutations happen all the time ?

Answer 10

Mutations are happening all the
time:
o Most do not affect phenotype;
o Some will influence phenotypes but
will not cause a new phenotype;
o On rare occasions, a mutation occurs
that does create a new phenotype.

Question 11

How variation occurs step by step …

Answer 11

• Original bird mutates causing new phenotypes
• If the new phenotype is not favoured by females it is not passed on
• If the new phenotype is favoured by females it is passed on and will out compete the old phenotype

Question 12

What are environmental variations caused by ?

Answer 12

Environmental variations are characteristics caused by

an organism’s environment

Question 13

Desired characteristics can include (Animals):

Answer 13

• The colour, length and texture of fur
• Produce large amounts of product, such as
  eggs and milk
• The size of the animal
• Tameness/ gentleness

Question 14

Desired characteristics can include (Plants):

Answer 14

• Disease and pest resistance
• Produce large amounts of product, such as grains and
  fruits
• Taste
• Large or unusual flowers

Question 15

Benefits of Selective Breeding

Answer 15

• New varieties produce more or better products, leading
  to more profit.
• Animals can be selected to reduce harm, such as
  breeding cows with no horns or tame wolfs (that
  eventually leads to dogs).

Question 16

Risks of Selective Breeding

Answer 16

• Reducing the genetic variance can lead to weaknesses to
  specific pests and diseases.
• Inbreeding – breeding together animals that are too closely
  related can result in:
• Selecting for rare diseases then selecting another positive
  trait, for example, large dogs are prone to bone cancer.
• Creating physical problems in the species, for example, pugs
  have trouble breeding because of their squished snout.

Question 17

What is selective breeding ?

Answer 17

Selective breeding is the process by which humans breed

plants and animals for particular genetic characteristics.

Question 18

Genetic Engineering

Answer 18

is a process that modifies the genome of an
organism, by inserting a gene with a desired
function or outcome, into the organism.

Question 19

Host bacterium

Answer 19

To carry the inserted gene

Question 20

DNA vector

Answer 20

This a DNA molecule, normally a virus or
a plasmid that is used to carry a foreign genetic
material into another cell.

Question 21

Restriction enzymes

Answer 21

cuts DNA at specific sites

Question 22

Ligases enzymes

Answer 22

joins DNA at specific points

Question 23

Sticky ends

Answer 23

the cut ends of gene and DNA vector

Question 24

Genetic Engineering Steps

Answer 24

1) The DNA is removed from the organism with the desired characteristic
2) A plasmid is removed from a bacteria cell
3) The gene of the desired characteristic is cut from the DNA strand using restriction enzymes
4) The plasmid is cut open with restriction enzymes
5) The sticky ends from both the plasmid and the DNA strand, are attached together using the enzyme ligase
6) The plasmid with the desired gene will be absorbed by the host bacteria cell
7) The bacteria reproduces, producing millions of identical bacteria with the desired characteristic

Question 25

Genetic engineering and crops

Answer 25

• Genetic engineering has been used to produce plants
  with increased yield and increase nutrition.
• A crop might be genetically engineered to be resistance
  to some type of disease or to produce bigger fruits.
• These crops are GM (genetically modified) crops.

Question 26

Some diseases are caused by the mutation of a single

gene.

Answer 26

• These diseases are typically inherited and affect the
  quality of life of the person who has it.
• In recent years, scientists have developed gene therapy.
• This involved transferring the non-faulty version of the
  gene into the person.

Question 27

Gene therapy has the potential to cure many diseases.

Answer 27

• However, there have been some hurdles to overcome;
• how to target the specific cells,
• unknown side-effects and
  finding a reliable way to get the genetic material into the cells.

Question 28

Benefits of GM in crops

Answer 28

Benefits
o Mass produce hormones that are needed in medicine
o It can improve crop yields by improving growth,
allowing crops to grow in harsh conditions and make
their own herbicide or pesticide
o Extra vitamins can be added to crops and grown where
there are deficiencies
o Greater yield could help solve world hunger

Question 29

Risks of GM in crops

Answer 29

o Might affect the growth of wildflowers, and the insects that
rely on them.
o Herbicides and pesticides reduce biodiversity
o Could affect human health
o People worry about the ethics of altering nature.
o Might outcompete their wild species, causing them to
become rare

Question 30

Embryo Cloning

Answer 30

1. Parent sheep with desired characteristics are chosen
2. The egg is fertilised with the sperm forming an
   embryo
3. The embryo is divided
4. The embryos are implanted into surrogate mothers
5. The offspring are all identical clones from the same
   biological parents

Question 31

Adult Cell Cloning

Answer 31

1) A diploid cell is taken from the sheep A to be cloned
2) The DNA is extracted
3) An egg cell is taken from sheep B
4) The egg cell is enucleated - the nucleus is removed
5) The DNA from sheep A is combined with the enucleated egg from Sheep B
6) The egg cell is given a mild electric shock to stimulate division by mitosis to from an embryo
7) The embryo is implanted into the surrogate mother
8) BABY

Question 32

Benefits of Cloning

Answer 32

• Produces many offspring with desirable
  characteristic.
• The study of clones and cloned embryos could
  advance medicine.
• It can be used to help endangered species or
  even bring back extinct species.

Question 33

Risks of Cloning

Answer 33

• Leads to shorter lived animals and physical
  disabilities.
• Many people are worried about the use of
  cloning on humans
• Reduces the gene pool
• Species with small gene pools are more likely
  to be completely wiped out by a disease

Question 34

What is a clone ?

Answer 34

Clones are two or more individual organism that are

genetically identical

Question 35

Cloning plants is useful for …..

Answer 35

Cloning plants is very useful for producing large amounts of identical plants quickly and cheaply

Question 36

What is the definition of tissue culture ?

Answer 36

taking a small sample of a plant and

growing it in growth hormones

Question 37

What is the definition of tissue cutting ?

Answer 37

taking a large sample of a plant and growing

it in compost with root growth hormones

Question 38

What is cloning animals useful for ?

Answer 38

Cloning animals is useful for producing identical offspring and for medical research