Biotechnology and Evidence for Evolution

Question 1

What is genetic engineering

Answer 1

Allows foreign modified DNA to be introduced into another cells

Question 2

What are the implications of genetic engineering

Answer 2

Can replace fault genes with healthy ones

Can produce synthetic hormones such as insulin for diabetics

Can produce vaccines

Question 3

Types of genetic engineering

Answer 3

Both types are cut by restriction enzymes

1. Straight cut and blunt ends
2. Staggered cuts and sticky ends

Question 4

Step 1 of genetic engineering

Answer 4

Isolate gene

Cut the gene using restriction enzyme at restriction site

Question 5

Step 2 of genetic engineering

Answer 5

Isolate a plasmid

Cut the plasmid with same restriction enzyme

Question 6

Step 3 of genetic engineering

Answer 6

Sticky ends and plasmid DNA anneal to each other

Spliced together by ligase

Question 7

Step 4 of genetic engineering

Answer 7

Bacteria takes up recombinant plasmid
Copies of recombinant plasmid are made
Copies placed into host cells
Host cells produce protein the gene codes for

Question 8

What is electrophoresis

Answer 8

Profiling technique

Used to determine individuals DNA profile

Question 9

Step 1 of electrophoresis

Answer 9

DNA fragments placed into cavities

Question 10

Step 2 of electrophoresis

Answer 10

Electric current passed through gel

Question 11

Step 3

Answer 11

DNA moves through to positive electrode from negative electrode

Question 12

Step 4

Answer 12

Smaller fragments move fast
Larger fragment move slower and shorter
Forms bands of gel

Question 13

Step 5

Answer 13

Forms a DNA fingerprint

Question 14

Implications of Electrophoresis

Answer 14

Tracing ancestry
Forensic science
Identifying hereditary diseases

Question 15

Definition of DNA sequencing

Answer 15

The determination of the precise order of nucleotides in a sample of DNA

Question 16

What is DNA sequencing

Answer 16

When building a DNA strand each new nucleotide is bonded to the hydroxyl group of the previous strand,
no hydroxyl group to bond to, no additional nucleotides can be added, so chain is terminated

Question 17

Step 1 of DNA sequencing

Answer 17

Double stranded DNA molecule is extracted

Question 18

Step 2 of DNA sequencing

Answer 18

Denatured at 90-96 degrees
split into two
only work with the template strand

Question 19

Step 3 of DNA sequencing

Answer 19

A primer is then annealed to the template strand

Question 20

Step 4 of DNA sequencing

Answer 20

The copies of the unknown DNA strand are made using 4 reactions mixtures
→ Template DNA strand with primers attached
→ DNA polymerase
→ Large amount of normal deoxynucleotides (dNTPs)
→ Small amount of fluorescently dyed synthetic nucleotides called Dideoxynucleotides (ddNTPs) that don’t have the hydroxyl groups present

Question 21

Step 5 of DNA sequencing

Answer 21

DNA polymerase works in the reaction mixtures by adding nucleotides to the primer to complete the complementary strand

Question 22

Step 6 of DNA sequencing

Answer 22

DNA polymerase continues to add free nucleotides until a synthetic dideoxynucleotide is used without the OH group which terminates the elongation of the sequence

Question 23

Step 7 of DNA sequencing

Answer 23

We are left with a range of strands of varying lengths, all ending with one of the 4 possible fluorescently dyed dideoxynucleotides
→ This allows us to overlay the strands of various lengths to reveal the complete sequence of bases of the unknown strand

Question 24

How to determine the sequence

Answer 24

multiple copies are added to an electrophoresis gel
a current is passed through the samples of varying lengths they move away from the negative electrode towards the positive electrode

Question 25

Implications of DNA sequencing

Answer 25

point mutations, insertions and deletions can be detected Diseases which can be determined such as cystic fibrosis

Question 26

Definition of Polymerase Chain Reaction

Answer 26

Used to multiply segments of DNA through a series of repeated cycles

Question 27

Step 1 of PCR

Answer 27

Denaturing Solution is heated (94-98) degrees The heat disrupts the hydrogen bonds causes separation of the DNA strands into single strands

Question 28

Step 2 of PCR

Answer 28

Annealing Temperature reduced to 50-65 degrees to allow a primer, to join the complementary strand At this temperature the primers anneal with the complementary sequence of DNA to start the replication from taq polymerase Forward and reverse primers are needed for both sides as they are designed to bracket the DNA region to be

Question 29

Step 3 of PCR

Answer 29

Extending Temperature rose again to 72 degrees Taq polymerase binds to primers The Taq polymerase synthesises new DNA strand Segments of single stranded DNA are replicated

Question 30

Applications of PCR

Answer 30

DNA profiling DNA from fossils can be amplified Detect hereditary diseases

Question 31

Gene Therapy

Answer 31

Aims to treat genetic abnormalities by replacing fault gene with healthy gene

Question 32

Cell Replacement

Answer 32

Stem cells are undifferentiated cells that are capable of mitotic divisions for long periods of time. stem cells are used in genetic engineering

Question 33

Gene therapy and cell replacement

Answer 33

Stem cells is taken from patient Mutant gene replaced with normal gene Cells multiply Cells transferred back into patient

Question 34

Human Genome Project

Answer 34

Enables us to identify mutation in a gene Enabled us to identify the abnormal protein causing the disease Gene therapy and genetic engineering are treatments which help genetic diseases

Question 35

Ethical Considerations

Answer 35

Autonomy, respect the right for an individual to be tested, if tested, to know and share the information Confidentiality, the genetic information is treated sensitively Equity, the right to fait and equal treatment regardless of genetic information

Question 36

Comparative DNA studies

Answer 36

In each species, the sequence of nucleotides varies. If more similar the DNA sequence then the organisms are more closely relate and are more likely to have a common ancestor.

Question 37

Example of Comparative DNA studies

Answer 37

Endogenous Retrovirus, a viral sequence that has become apart of an organism's genome

Question 38

Comparative Mitochondrial DNA studies

Answer 38

The higher the degree of similarity between mtDNA of two individuals the closer their evolutionary relationship

Question 39

Example of Comparative Mitochondrial DNA studies

Answer 39

MtDNA

Question 40

Comparative Protein Sequence Studies

Answer 40

Every protein has a number of amino acids. Similarity of amino acid sequence is evidence of close evolutionary relationship

Question 41

Example of comparative protein sequence studies

Answer 41

Ubiquitous protein, Cytochrome C which performs basic tasks for cellular energy. To compare Cytochrome C sequences they need to be aligned so that the maximum number of positions containing the same amino acid can be determined. The more similarity between the molecules, the more recently they have diverged from a common ancestor

Question 42

Phylogenetic Trees

Answer 42

Comparative studies allow scientists to work out the evolutionary relationship between groups of organisms Phylogenetic tree represents the evolutionary relationships between organisms derived from a common ancestor The ancestral organism forms the base of the tree and these organisms that have arised from it are placed on the ends of the branches

Question 43

Comparative Embryology Studies

Answer 43

Comparative embryology studies will show how the closely related organisms will show similar anatomical development in the embryonic stages of life which will show they all share a common ancstor

Question 44

Example of Comparative Embryology Studies

Answer 44

In all vertebrae species: - Embryonic gill pouches - Presence of a tail - Two chambered heart

Question 45

Comparative Homologous Structures

Answer 45

Organs that are very similar in structure but have different functions due to environmental selection pressure. Organisms possessing homologous structures that are similar are more likely to share a common ancestor

Question 46

Example of Homologous Structures

Answer 46

Forelimb of the vertebrae

Question 47

Comparative Vestigial Organs

Answer 47

The structures which are the remains of organs that were required in ancestral form. These organs are no longer essential. These organs suggest ancestral relationship with organisms that have functional forms of the same organs

Question 48

Example of Vestigial Organs

Answer 48

- Nictitating membrane - Third molars - Appendix