1. Genetics

2. Diversity of living things
There are over 1.5 million speices of organisms on earth – living things.
IT MAKES IT MORE MANAGEABLE TO SPLIT THELIVING THINGS UP INTO GROUPS – SUB CLASSIFIY THEM TO SPECIES!

3. Species
A species is a group of similar organisms that are capable of naturally interbreeding with each other to produce fertile offspring.
Mountain Gorilla
Physical CharacteristicsFew animals have sparked the imagination of man as much as the gorilla, the largest of the living primates. Most gorillas live in inaccessible regions in various dense forests in tropical Africa, and one subspecies, the mountain gorilla (Gorilla beringei beringei), was not even known to science until 1902.
The mountain gorilla has a robust build with long, muscular arms, a massive chest, and broad hands and feet. It is the hairiest race of gorillas; its long, thick black hair insulates it from the cold of living at high elevations.
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Habitat
The world's remaining mountain gorillas live within four national parks, split in two regions that are 45 kilometers (28 miles) apart.
One population of mountain gorillas inhabits the Bwindi Impenetrable National Park in Uganda. A census in 2003 recorded 340 gorillas here.
The second population of mountain gorillas is found in a mountainous region referred to as the Virungas, which includes Mgahinga Gorilla National Park (Uganda), Volcanoes National Park (Rwanda) and Virunga National Park (Democratic Republic of Congo). Approximately 380 gorillas are found in the Virungas.
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Behavior
Although strong and powerful, gorillas are generally gentle and shy. They live in groups of 2-40 individuals, averaging about 11. Groups are led by a dominant male, the silverback, named for the silvery gray hairs that grow when the male matures. The silverback serves as the chief leader and protector of the group, to whom all group members defer. He decides when and where to forage, rest and sleep, arbitrates disputes among his family members and protects them from rival silverbacks or human predators.
Mountain gorillas have a slow rate of reproduction. This slow reproduction makes this species even more threatened. In a year lifetime, a female might have only 2-6 living offspring. Females give birth for the first time at about age 10 and will have offspring every four years or more. A male reaches sexual maturity between 10 and 12 years. Able to conceive for only about three days each month, the female produces a single young and in rare cases twins.
Newborn gorillas are weak and tiny, weighing about 4 pounds. Their movements are as awkward as those of human infants, but their development is roughly twice as fast. At 3 or 4 months, the gorilla infant can sit upright and can stand with support soon after. It suckles regularly for about a year and is gradually weaned at about 3.5 years, when it becomes more independent.
Diet
It is perhaps surprising that an animal as large and strong as the mountain gorilla is primarily an herbivore. Mountain gorillas eat over 100 different species of plants. They rarely need to drink since their diet is so rich in succulent herbs, from which they get their water.
Predators and Threats
The primary threat to mountain gorillas comes from forest clearance and degradation, as the region's growing human population struggles to eke out a living. The African Wildlife Foundation (AWF), in collaboration with Fauna and Flora International and World Wide Fund for Nature, established the International Gorilla Conservation Program (IGCP) to safeguard the last remaining mountain gorillas.
IGCP works on three levels: Strengthening gorilla habitat protection through regional collaboration, researching the dynamic between the human population and the natural habitat/wildlife, and working with local communities to develop livelihood strategies that are complementary to conservation objectives.
This coalition has been a tremendous success, but support is still greatly needed. The most endangered of the gorilla subspecies, only about 720 mountain gorillas remain in the wild.
GERIILLAS –SUBSPECIES IS A MOUNTAIN GUERRILA
Did You Know?
There are only about 720 mountain gorillas left in the world.
Humans and gorillas are 98% genetically identical.
Male silverback gorillas can weigh pounds more - and are about 10 times stronger - than the biggest American football players.
When the group is attacked by humans, leopards, or other gorillas, the silverback will protect them even at the cost of his own life.

4. There can be individuality within species –differences between members of a species which does not affect their ability to interbreed.
If the two groups do not interbreed because of something intrinsic to their genetic make-up (perhaps black frogs do not find white frogs sexually attractive, or they breed at different times of year) then they are different species.
If, on the other hand, the two groups would interbreed freely provided only that some external barrier was removed (perhaps there is a waterfall too high for frogs to scale, or the populations are far distant from one another) then they are subspecies. Other factors include differences in mating behavior or time and ecological preferences such as soil content.

5. Heredity
The passing on of traits from parents to offspring by means of genes
Example eye colour!

6. Are you able to…
Define species?
Explain what heredity is?

7. Chromosomes Nuclear membrane Chromatin Nuclear pore
Humans have 2n=46 – 23 chromosome pairs inside the nucleas of each cell.

8. Chromosomes Chromosomes are long strands of DNA coiled up with protein
Protein holds it up tight to fit into the nuclues about 60% protein and 40% Dna
Dna may be coding or non coding
Protein called histones

9. Gene
A gene is a section of DNA that causes the production of a protein.
Strand of DNA
Gene is the unit of heredity
Genes are found on chromosomes
Genes carry the instructions to make a particular substance
Genes helps regulate a characteristic of an organism.

10. Gene expression •Every protein made has an effect on the organism
Gene expression is the way in which genetic information in a gene is decoded in the cell and used to make a protein
•Every protein made has an effect on the organism

11. Gene expression Characteristics = heredity + environment
Gene Expression produces characteristics or traits that are inherited
Example: Gene for Tallness
Organism is small – Why?
Maybe due to poor nutrition
Characteristics =
heredity + environment

12. Check your learning… State the location of chromosomes
Tell about the structure of a chromosome
Tell what genes are and where they are found
Give examples of some traits controlled by genes

13. 2.5.4 DNA structure
Double helix

14. DNA structure DNA =Deoxyribonucleic Acid DNA is a very long molecule
It is made up of two parallel strands
The strands are linked together by paired bases.
Each strand is made up of bases which bond with bases from the other strand to link the two strand together
The DNA Spiral Ladder

15. DNA structure There are four different bases that are found in DNA
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)

16. The Base Pair Rule A T G C Adenine only joins to Thymine
Guanine only joins to Cytosine
The bases can occur in any sequence along a strand of DNA But the sequence must be complimentary to the sequence on the other strand

17. Triplet base code Coding DNA contains information to make proteins..
The sequence of the bases on a DNA strand directs what protein our body will make.
DNA codes for each amino acid by using a sequence of three consequtive bases.
The amino acids are joined together to make a protein

18. Coding DNA
Def Coding DNA is the DNA that contains information to make proteins
Strand of DNA
Only about 3% of DNA is composed of genes
GENES ARE MADE UP OF CODING DNA

19. Non Coding DNA
Non coding DNA is the DNA that does not contain information for the production of protein
Also called “Junk DNA”
97% of DNA is non coding DNA or junk DNA
They are now thought to play a role in gene expression
Strand of DNA
Non coding DNA

20. Can you.. Describe the structure of a chromosome
Tell what genes are and where they are found
Tell what DNA stands for
Name the four bases found in DNA
Know how base pairing happens in DNA
Distinguish between coding and non coding DNA

21. Nucleic acid structure – HL
Deoxyribonucleic Acid (DNA) is a nucleic acid
It is made up of nucleotide units
Its shape is called the double helix

22. Nucleotide structure Each nucleotide unit has: 1. A phosphate
2. A deoxyribose sugar
3. one of four nitrogenous bases
adenine, ( a purine)
guanine ( a purine)
cytosine, ( a pyrimidine)
or thymine( a pyrimidine)

23. Purine and pyrimidine couples!
Adenine (purine) bonds to thymine (pyrimidine)
Guanine (purine) bonds to cytosine (pyrimidine)
Bases pairs bond to each other by Hydrogen bonding

25. Try now..
HL 2011 q9A,

26. To isolate DNA from a plant tissue

27. Step 1
Add 10 ml washing-up liquid and 3 g salt to a graduated cylinder. Make up to 100 ml and stir.

28. Step 2
Add chopped onion to a beaker. Pour in the salty washing-up liquid solution and stir.

29. Stand the beaker in a water bath at 60°C for 15 minutes.
Step 3
Stand the beaker in a water bath at 60°C for 15 minutes.

30. Cool the mixture by standing the beaker in an ice bath for 5 minutes.
Step 4
Cool the mixture by standing the beaker in an ice bath for 5 minutes.

31. Blend the mixture for no more than 3 seconds.
Step 5
Blend the mixture for no more than 3 seconds.

32. Filter the blended mixture through coffee filter paper.
Step 6
Filter the blended mixture through coffee filter paper.

33. Add 2-3 drops of protease enzyme to 10 ml of the onion extract.
Step 7
Add 2-3 drops of protease enzyme to 10 ml of the onion extract.

34. Step 8
Very carefully, pour 10 ml of ice cold ethanol onto the surface of the onion extract.

35. DNA forms at the interface of the ethanol and extract.
Step 9
DNA forms at the interface of the ethanol and extract.

36. Draw the DNA out of the solution by wrapping it around a glass rod.
Step 10
Draw the DNA out of the solution by wrapping it around a glass rod.

39. 2.5.4 DNA Profiling
DNA Profiling is the method of cutting up a persons DNA into fragments that can be used to make a pattern of bands that are unique to each person.

40. 2.5.4 DNA Profiling 1. Cells are broken down to release DNA
2. DNA strands are cut into fragments using enzymes
3. Fragments are separated on the basis of size
PCR MAY BE USED IF NOT ENOUGH MATERIAL IS PRESENT – POLYMERASE CHAIN REACTION
RESTRICTION ENZYMES BREAK UP DNA AT SPECIAL PLACES – ISOLATED FORM DNA OF INVADING VIRUSES – SECTIONS CUT OUT CALLED RESTRICTION FRAGMENTS
3. Gel electro phoresis is used – invisible dna in a glass tank – sugar based gel. Electric current applied which draws neg charged dna along tank, small bits can get through porius gel quicker than larger bits. May be combined wutg radioactive material to make a flourescent glow on the DNA
4. VERY UNLIKELY THAT ANY TWO PPL WILL HAVE SAME DNA PROFILE ALTHOUGH IDENTICAL TWINS WILL HAVE SAME DNA PROFILE!
4. The pattern of fragment distribution is analysed.

41. DNA Profiling applications
Can be used to investigate crimes!
A DNA profile can be made form blood , semen, hair, saliva sample found at a crime scene.
The DNA profile can then be compared to victims and suspects DNA profiles in a crime case

42. DNA Profiling applications
Can be used to resolve medical issues!
Paternity and maternity cases resolved by comparing child's DNA profile with parent DNA profile.
Each band in a child's profile must match a band form the either the mother or the father’s profile.
Immigration cases, financil inheritance cases

43. Check your learning.. What DNA Profiling is
How DNA profiling is done (4 steps)
Why DNA profiling is used – 2 examples

44. Genetic screening Foetal screening or Adult screening!
Def Genetic screening is doing diagnostic tests on an organism to identify the presence or absence of changed genes.
But could It cause the potential for discrimination??
Foetal screening or
Adult screening!
DNA PROFILING TESCHINQUES ARE USED.
RESEARCHES FAMILY HISTORY OF INHERETED DISORDERS AND ADVISES PARENTS ON LIKLIHOOD OF SUCH A DISORDER AFFECTING CHILDREN.
Changed gene – may have been incorrectly copies and can cause sever effects
cystic fibrosis – ppl can choose whether or not to have children – could it encourage termination?
Potential discrimination – ethical, ? Untreatable =- should they know they will develop in at 40 and die? Insurance companies / employers/ embarrassment / decde who you will have children with?

45. Cystic fibrosis

46. Albinism

47. DNA Replication

48. Brainstorm Why do cells need to divide?
What happens to a cell during its interphase stage?
What are the names of the 4 stages in Mitosis?

49. 2.3.4 Mitosis
Mitosis
Interphase
Def Mitosis is the division of the nucleus to produce two daughter nuclei, containing identical sets of chromosomes.
Daughter nuclei with chromosomes identical to parent cell
Revision of Mitosis

50. Mitosis: Stage 1
The chromatin shortens, thickens and double stranded chromosomes become visible in the nucleus.
The Nuclear membrane breaks down
Fibres are formed :
Fibres
Cell membrane
Double stranded chromosomes
There are four main stages in Mitosis
Nucleus
Nuclear membrane
Revision of Mitosis

51. Mitosis: Stage 2 Fibres attach to the chromosomes.
The chromosomes line up along the centre of the cell.
Revision of Mitosis

52. Mitosis: Stage 3
Chromosomes are pulled apart to opposite ends of the cell
Chromosomes pulled apart
Revision of Mitosis

53. Mitosis: Stage 4
A nuclear membrane forms around each set of new chromosomes and the cell divides in two
Cell divides in two
Revision of Mitosis

55. Replication of DNA
During the Interphase stage of the cell cycle each chromosome in the nucleus makes a copy of itself.

56. Replication of DNA – stage 1
(1) The double helix unwinds and the DNA strands separate.
Enzymes help it to do this by breaking the hydrogen bonds between the base pairs. The helix opens.

57. Replication of DNA – stage 2
Base pairing occurs between the bases on the original strands of DNA and new free bases that enter the nucleus.
New complementary strands of DNA are formed alongside original strands.
COMPLEMENTARY = CORRECTLY MATCHING WITH BASE PAIR RULES
C – G
A- T

58. Replication of DNA – Stage 3
Two new double helixes of DNA are made – each identical to the original DNA double helix and each other.
Each new DNA double helix is made up of:
½ old DNA and ½ new DNA!

59. Check your learning.. What happens during interphase in the cell cycle
What forces hold DNA strands together usually?
During which stage of DNA replication do the strands separate?
What does complementary mean?
Where do the extra bases come from to make the new strands?
How do new DNA strands compare to the original strand and to each other?