Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Make your likes visible on Facebook?

Connect your Facebook account to Prezi and let your likes appear on your timeline.
You can change this under Settings & Account at any time.

No, thanks

4. Genetics

Notes for IB Biology
by

Ruru (Juan Ru) Hoong

on 21 October 2014

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of 4. Genetics

4. Genetics I
4.1 Chromosomes, genes, alleles and mutations
4.2 Meiosis
2.3 Theoretical Genetics
4.4 Genetic engineering and biotechnology
4.1.1 State that eukaryote chromosomes are made of DNA and proteins
Eukaryotic cells contain chromosomes (long thin strands of DNA coiled around associated proteins)
4.1.2 & 4.1.3
Define gene, allele, genome, and gene mutation.
4.1.4 Explain the consequence of a
base substitution mutation in relation to
the processes of transcription and translation, using the example of sickle-cell anaemia
Base substitution mutation: insertion of an incorrect nucleotide
2.2.1 Draw and label a
diagram of the ultrastructure of
Escherichia coli
- example of a prokaryote.
2.2.3 Identify structures in electron micrographs of E. coli.
2.2.4 State
that prokaryotic cells
divide by binary fission.
DNA is copied, cell elongates
2 daughter chromosomes are attached to different regions of the plasma membrane; partitioning of DNA by microtubule-like fibres made of protein
Divides into two genetically identical cells (asexual reproduction)
2.3.1 Draw and label a diagram
of the ultrastructure of a liver cell, as an example of an animal cell.
2.3.5 State the differences between plant & animal cells.
Plants
Cell wall of cellulose present (fixed, angular)
Chloroplasts
Large, central vacuole
Store carbohydrates as starch
Do not contain centrioles
2.3.6 Outline roles of extra cellular components
Extracellular Matrix (ECM)
Form supporting network for cell membrane
Allows adjacent cells to attach to one another and intersect
Cell migration and movement due to interactions
Cell Wall (in both plant and fungi cells)
Provides support
Maintains cell shape
Prevents excessive water uptake
4.4.4 Describe the application of DNA profiling to determine paternity and also in forensic investigations.
4.4.6 Outline three outcomes of the sequencing of the complete human genome
The Human Genome Project was started as an international collaboration to determine the entire base sequence of the human genome.
4.4.7 State that, when genes are
transferred between species, the amino acid sequence of polypeptides translated from them is unchanged because the genetic code is universal.
Gene technology/engineering/GM involves the transfer of genes from one organism to another (completely different species with the desirable characteristics)
4.4.9 State two examples of
the current uses of genetically modified crops or animals.
GM Sheep: Production of factor XI in sheep's milk
4.4.13 Discuss the ethical issues of therapeutic cloning in humans
2.3.3 Identify
structures in electron micrographs of liver cells.
2.3.4 Compare prokaryotic & eukaryotic cells.
SIMILARITIES
no nucleus, organelles, little compartmentalization
DIFFERENCES
Both have cytoplasm
Both have DNA
Both have plasma membrane
Both have ribosomes
Both carry out functions of life
Prokaryotes
DNA in ring/strands, free in cytoplasm
No mitochondria or endoplasmic reticulum
Ribosomes are not dense; small: 70S
Always present cell wall of peptide
No chloroplasts
Eukaryotes
DNA as chromatin, nucleus present
Mitochondria & endoplasmic reticulum
Ribosomes are dense; large: 80S
Only plant cells have cellulose cell wall
Chloroplasts present in plant cells
Animals
Cell wall absent
Chloroplasts absent
Small vacuoles/ not present
Store carbohydrates as glycogen
Contain centrioles in centrosome
4.4.1 Outline the use of the polymerase chain reaction (PCR) to copy and amplify minute quantities of DNA
4.4.2 State that, in gel electrophoresis, fragments of DNA move in an electric field and are separated according to their size.
Restriction enzymes used to cut DNA into fragments at very precise points in the base sequences
Each individual has a unique DNA sequence, so positions of cutting sites will vary and produce a mixture of different fragments sizes
Fragments placed in a well in a plate of gel, electric field applied - smaller fragments travel further, larger behind; stained and separated
4.4.11 Define clone
Only a small amount of DNA available, but large amounts of DNA needed to create a profile to undergo testing)
DNA from blood, semen, skin tissues, etc. heated to denature and separate DNA double helix
Primers, polymerase, nucleotides added using DNA polymerase from bacterium
Repeated about 30 times - A standard reaction of 30 cycles would yield 1,073,741,826 copies of DNA
4.4.3 State that gel electrophoresis of DNA is used in DNA profiling
DNA profiling is matching the DNA from a sample to a known individual.
Paternity: DNA samples from woman, man and the child and DNA sequences compared to determine paternity
Forensic investigations: Check 13 key 'short tandem repeat' sequences in DNA samples, vary considerably between individuals (1/1,000,000,000)
Used as evidence in court convictions, etc.
4.4.5 Analyze DNA profiles to draw conclusions about paternity or forensic investigations
Look for similarities in DNA
Improved diagnosis/ identification of genetic disease
Earlier detection of genetic susceptibility to disease; so environmental factors that trigger the disease can be avoided
Allows for production of new drugs based on DNA base sequences of the genes/ structure of proteins coded by genes
Discovery of number of genes, gene locus; protein structure
More information on the origins, evolution and migration of humans
4.4.8 Outline a basic technique used for gene transfer using plasmids, a host cell (bacterium, yeast, or other cell), restriction enzymes (endonucleases), and DNA ligase.
INSULIN
Diabetics cannot control the concentration of glucose in their blood, sometimes due to lack of insulin. They need daily injections of the hormone - which used to be obtained from pigs and cattle, but for safety, religious, and expense reasons, the gene for human insulin is isolated and transferred to E. coli bacteria.
Gene that codes for insulin identified in human pancreatic cell; messenger RNA which codes for insulin is extracted from a human pancreatic cell and copied to make DNA using reverse transcriptase enzyme, cut for sticky ends
Circular piece of DNA (plasmid) removed from bacteria, cut by restriction endonuclease enzyme at specific base sequences to produce sticky ends as well
Human-insulin making gene put into plasmid using ligase (enzyme) by making sugar-phosphate bonds and complementary base pairing between extra bases on ends of gene and plasmid
Recombinant plasmid (vector) with code for insulin put back into bacteria (host cell)
Bacteria multiply rapidly inside industrial fermenter and insulin is filtered out and purified
Factor XI: part of the cascade of clotting factors that form the chain leading to a protective clot
Factor XI deficiency 1/100 000
Disease similar to hemophilia: prone to bleeding
Used to obtain factor XI from fresh-frozen plasma (considerable amounts needed)
Production of clotting factors in GM sheep's milk lead to new and better treatments
MAIZE
Maize crops are often destroyed by insects, so a gene that codes for a protein called Bt toxin is transferred from the bacterium
Bacillus thuringiensis
to maize crops, which kills the insects.
Potential benefits:
Increases yield of crops (esp with growing population, provides more food, with less land needed to grow)
Can grow in regions that were previously not viable (reduces need for deforestation)
Reduce the need to apply potentially harmful pesticides; also reducing economic cost
Allows for introduction of characteristic that wasn't previously available in the gene pool
4.4.10 Discuss the potential benefits and possible harmful effects of one example of genetic modification.
Possible harmful effects:
Possible unknown harmful effects on humans (eg. allergic reaction, etc.)
Long-term effects in the environment unknown, may affect wild populations (if cross-pollinated accidentally, competition with native plants)
Reduction in natural biodiversity
GM seeds/plants more expensive; poor farmers cannot buy them, hurting local economy
Human food crops controlled by small number of biotech companies (monopoly)
A clone is a group of genetically identical organisms or a group of cells derived from a single parent cell.
4.4.12 Outline a technique for cloning using differentiated animal cells
Somatic-Cell Nuclear Transfer (SCNT)
method of reproductive cloning using differentiated animal cells.
Nucleus from a somatic cell is removed (eg. udder cells from 6-year of ewe) and cultured in medium that deprives cells of essential nutrients, thereby causing genes to become quiescent (inactive).
A female animal (e.g. sheep) is treated with hormones (such as FSH) to stimulate the development of eggs, and nucleus from an egg cell is removed (enucleated), thereby removing the genetic information from the cell
The egg cell is fused with the somatic cell nucleus using an electric impulse, making the egg cell diploid
An electric shock is delivered to stimulate the egg to divide, and once this process has begun and formed an embryo, it is implanted into the uterus of a surrogate
The developing embryo will have the same genetic material as the sheep that contributed the diploid nucleus, and thus be a clone (eg. Dolly the sheep)
THERAPEUTIC CLONING
is used to produce tissue or organs that is needed by a human patient, using human embryos as a source of embryonic stem cells (undifferentiated).
They can be used for medical treatment and to repair damaged parts of the body.
Taking embryonic stem cells from an embryo is painless because the embryo has no nervous system
Cells can be taken from embryos that have stopped developing/from IVF and so these cells would have died anyway
Embryonic stem cells can be used for therapies that save lives and reduce pain for patients
Stem cell research may pave the way for future discoveries and beneficial technologies that would not have occurred if their use had been banned
Involves the creation and destruction of human embryos
Involves killing of excess embryos, which some compare to the killing of a human life
With additional cost and effort, alternative technologies may fulfill similar roles (e.g. nuclear reprogramming of differentiated cell lines)
Can result in embryonic stem cells forming tumours, which is highly dangerous for patients already suffering from degenerative diseases
Gene
: a heritable factor that controls a specific characteristic
Allele
: a specific form of a gene that shares the same gene locus (position) as other alleles of the gene but differs by small differences in base sequence
Genome
: the entire genetic information of the organism
Gene mutation
: a change in the base sequence of a gene
1. Sickle-cell anemia is due to base substitution mutation
2. Haemoglobin made out of 4 sub-units: 2 alpha, 2 beta chains
3. Gene coding of polypeptide beta chains affected
4. Normal gene: coding on antisense strand CTC, mRNA triplet GAG
5. Sickle: coding on antisense CAC, so mRNA triplet GUG
6. When anticodon on tRNA pair up, gives valine instead of glutamic acid
7. Different properties for different amino acids
Symptoms of sickle-cell anaemia
sickle-shaped cells and haemoglobin stick together
harder to carry oxygen: anemia and fatigue
can lead to brain damage, headache, even death
kidney problems, jaundice, heart disease
pain from production of lactic acid
carrier has resistance to malaria
2.2.4 State
that prokaryotic cells
divide by binary fission.
DNA is copied, cell elongates
2 daughter chromosomes are attached to different regions of the plasma membrane; partitioning of DNA by microtubule-like fibres made of protein
Divides into two genetically identical cells (asexual reproduction)
2.2.4 State
that prokaryotic cells
divide by binary fission.
DNA is copied, cell elongates
2 daughter chromosomes are attached to different regions of the plasma membrane; partitioning of DNA by microtubule-like fibres made of protein
Divides into two genetically identical cells (asexual reproduction)
2.3.1 Draw and label a diagram
of the ultrastructure of a liver cell, as an example of an animal cell.
2.3.6 Outline roles of extra cellular components
Extracellular Matrix (ECM)
Form supporting network for cell membrane
Allows adjacent cells to attach to one another and intersect
Cell migration and movement due to interactions
Cell Wall (in both plant and fungi cells)
Provides support
Maintains cell shape
Prevents excessive water uptake
2.3.3 Identify
structures in electron micrographs of liver cells.
Full transcript