Classification

Question 1

What is a species?

Answer 1

A group of living organisms with similar characteristics which can interbreed to produce fertile offspring

Question 2

What is taxonomy?

Answer 2

The science of classification of living things

Question 3

Why must classification be flexible?

Answer 3

So new organisms can be added

So fossils can be added

Question 4

What does the process of classification involve?

Answer 4

Giving living things an agreed name and imposing a scheme upon the diversity of living things

Question 5

Explain the binomial system of naming?

Answer 5

Genus name then species name

Question 6

Give all the groups in the hierarchical scheme of classification

Answer 6

Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 7

What are analogous structures?

Answer 7

Resemble each other in function but different in fundamental structure

Question 8

What are homologous structures?

Answer 8

Structures which are built to a common plan but adapted for different purposes

Question 9

What is an artificial classification?

Answer 9

Classification based on analogous structure

Question 10

What is a natural classification?

Answer 10

Classification based on similarities and differences due to close relationships between organisms that share a common ancestor (based on evolutionary links)

Question 11

How can the relatedness of species be estimated?

Answer 11

Looking at the amounts of variation in the DNA

Question 12

What is DNA sequencing

Answer 12

The process of determining the order of the nucleotides in a DNA molecule

Question 13

What are the principles of DNA sequencing?

Answer 13

Extract DNA from tissues
Cut up DNA molecule at specific points with enzymes Tag bases with fluorescent dye
Separate with electrophoresis
Determine and compare base sequence

Question 14

Explain how DNA is extracted from tissue samples

Answer 14

Mechanically broken up
Filtered
Cell membrane broken down with detergents
Protease breaks down protein framework
DNA precipitated out with ethanol and then put in pH buffer solution

Question 15

Explain how DNA is chopped up

Answer 15

Addition of restriction enzymes like restriction endonucleases cuts DNA at a particular sequence of bases

Question 16

Where do you find restriction endonucleases and why?

Answer 16

In bacteria to stop infection from viruses by cutting up viral DNA

Question 17

What is electrophoresis?

Answer 17

A method of separating charged ions in a fluid

Question 18

What gel is used in electrophoresis and how do they work?

Answer 18

Agar gel or PAG. Small pores which act as a molecular sieve. Small particles move fast large particles move slow

Question 19

Why does DNA migrate towards the positive pole?

Answer 19

Phosphate groups on the DNA fragments are negative

Question 20

Why is classification needed?

Answer 20

Trace evolutionary links
Predict characteristics
Identify and name species

Question 21

Why is a binomial system of naming needed?

Answer 21

So that everyone has the same name for species worldwide

Question 22

What is molecular phylogeny?

Answer 22

The analysis of molecular differences in the DNA sequence of organisms to establish their evolutionary relationships

Question 23

What methods can be used to determine evolutionary links?

Answer 23

DNA sequencing
Gel electrophoresis
Bioinformatics
DNA hybridisation

Question 24

Summarise the stages of gel electrophoresis

Answer 24

Obtain DNA sample - amplify by PCR
Cut with restriction enzymes
Put into wells in the gel electrophoresis tank
Apply current so it separates out
Add dye to stain the bands
Compare banding patterns

Question 25

How can you compare the banding patterns of two organisms?

Answer 25

Number of bands Width of bands Position of bands

Question 26

Summarise the stages of DNA hybridisation

Answer 26

DNA sample heated to separate into single strands of DNA Mixed with single stranded bits of DNA from another species Hydrogen bonds form between comp. base pairs Heated to find temp at which all bonds break Higher temp = more bonds = closely related

Question 27

What is bioinformatics?

Answer 27

the storage, manipulation and analysis of biological information via computer science

Question 28

What are the 5 kingdoms?

Answer 28

``` Prokaryotae Proctotista Animalia Fungi Plantae ```

Question 29

Why did the 5 kingdom model have to be changed?

Answer 29

Because extremophiles were discovered and they were found to be slightly different to normal prokaryotes

Question 30

What are extremophiles?

Answer 30

Species of bacteria which can survive in extremely hostile environments

Question 31

What evidence was there to change from 5 kingdom to 3 domain?

Answer 31

Extremophiles were found to have bigger ribosomal RNA than normal prokaryotes

Question 32

Name the three domains and explain each one?

Answer 32

Archae - extremophiles Eubacteria - true bacteria Eukaryota - all the eukaryotes

Question 33

What are the ways in which the scientific community can validate data?

Answer 33

Scientific journals Peer review Conferences

Question 34

Why do we use the same system universally?

Answer 34

So its accessible to all | Everyone can add to it

Question 35

What is a hierarchical scheme of classification?

Answer 35

Where each successive group has more species within it