Science Knowledge: Science 2: Life Processes and living things K2.4 Variation, Inheritance

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Science Knowledge Science 2 Life Processes and
living things K2.4 Variation, Inheritance
Evolution

• This document can be freely copied and amended if
  used for educational purposes. It must not be
  used for commercial gain. The author(s) and web
  source must be acknowledged whether used as it
  stands or whether adapted in any way.
• Subject Knowledge K2.4 Variation, Inheritance
  Evolution (download 2). Authored by Liz Lakin and
  Keith Ross, University of Gloucestershire.
  accessed from http//www.ase.org.uk/scitutors/
• date created March 2006

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Variation, Inheritance Evolution Learning
Objectives

• To explore the science behind the headlines
• To establish a timeline of events leading to our
  current scientific understanding

• To identify the big ideas in this field of
  biology and recognise how they are interlinked
• To discuss modern applications their associated
  issues

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http//www.ncseweb.org/evc/EvsC-cover_400.jpg
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http//users.hol.gr/dilos/prehis/Darwcar.jpg
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Variation
http//www.healthcastle.com/images/vegetables.jpg
www.picture-newsletter.com/
vegetables/index.htm
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Charles Darwin recognised the significance of
variation in a range of organisms
www.nmm.ac.uk/.../ outputRegister/lowhtml
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The Story of the Peppered Moth
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Human Evolution
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Selection?

• What we are is determined by our genes and our
  environment

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Father of Modern Genetics

• Gregor Mendel
• Austrian Monk (1850s)
• Identified the patterns of inheritance
• Laws of Inheritance

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Multiple choice questions

• The questions in the slides that follow are taken
  from a set of over 100 available from
• www.escalate.ac.uk/1141
• Percentages quoted in the slides are for a group
  of 100 trainee primary teachers on entry to ITE,
  having obtained a C or better at GCSE, usually
  two or three years previously.
• This gives secondary trainees an insight into the
  misconceptions that survive a GCSE course, and
  all trainees some comfort that they are not alone
  with their own misconceptions about how genetics
  and evolution works.

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Recessive Genes

• If you and your partner both carry the disease
  for cystic fibrosis (but are not
• sufferers), what would be the probability that
  your children will then inherit
• the actual disease?
• a. 25 (1 in 4) 5
• b. 33.3 (1 in 3) 19
• c. 50 (1 in 2) 35
• d. 100 (1 in 1 - certainty) 39
• ( are for a survey of post GCSE students see
  notes)

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Mendelian Cross

• Both parents carry the recessive gene for cystic
  fibrosis (c) they also carry the ordinary gene
  (C). The cross can be summarised as follows

Father Mother C
C CC Cc CF carrier
c Cc CF carrier cc CF sufferer
CC
c
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Eye Colour

• In eye colour the allele for brown eyes is
  dominant (B) and the allele for blue eyes is
  recessive (b). Try some different crosses with
  homozygous parents (BB or bb) and heterozygous
  parents (Bb)

Father Mother B b
b Bb bb
b Bb bb
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So what are Genetics?

• Look at the person next to you and identify as
  many external similarities between the two of
  you, as you can.
• Now identify as many differences as possible.

Our common inheritance as humans
The tiny amount of variation in our genes
We share half our genes with bananas and 99 with
the chimpanzee
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One fertilised cell to an organism!
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Development of an egg

• What will happen to the weight of a fertilised
  bird's egg from time of laying to just before the
  chick hatches?
• It gets lighter  6
• It gets heavier  54
• It stays much the same  35
• ( are for a survey of post GCSE students see
  notes)
•    

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(No Transcript)
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Genes

• What are your genes?
• Do bacteria have genes?
• Is the genetic information in the sex cells the
  same as in other cells?

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Lets look at cells

• Several types
• 75 billion in a human being
• Capable of carrying out many different functions
  e.g.
• Protection
• Movement
• Excretion

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Importance of Proteins

• Click on the one statement you most agree with
  about why proteins are so important to living
  things.
• a. They are a nutritious food 8
• b. They are the enzymes in our bodies which
  enable our cells to work. 37
• c. When combined with oxygen, lots of energy is
  given off 6
• d. Protein provides the structural material in
  all living things 45
• ( are for a survey of post GCSE students see
  notes)

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Material of Inheritance

• What are the requirements of hereditary material?
• Store information
• Permanence
• Ability to change (mutate)

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Unique function of DNA

• Stores information for protein synthesis
• Makes copies of itself self replication
• Able to change/vary/mutate

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DNA

• Deoxyribonucleic Acid
• Molecular language 4 different letters
• Codon three letter word most code for an
  amino acid
• GENE sentence of many words (amino acids) which
  enables it to build PROTEINS
• Proteins are enzymes that enable reactions to
  take place in cells

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base, nucleotide, gene, chromosome

• The following terms all relate to the DNA
  molecule. List them in relation to their size,
  starting with the smallest
• a gene
• b nucleotide
• c chromosome
• d bases
• (4 of the BEd Students got it right)

http//en.wikipedia.org/wiki/Nucleotide
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DNA

• Click on the four sentences about human DNA that
  are true.
• a. It carries the code to make proteins. 50
• b. It can pass from one generation to the next.
  83
• c. It can make copies of itself. 68
• d. It is a single stranded molecule. 26
• e. It is made of protein. 51
• f. It is identical in almost every cell of our
  body. 66
• ( are for a survey of post GCSE students see
  notes)

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Protein Synthesis

• A simulation

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Link to HOME Quiz
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Variation from mutation

• Which two of the following processes leads to
  'variation' in the offspring
• a. Cell cloning. 4
• b. Gamete formation. 34
• c. Mitosis (normal cell division). 51
• d. Meiosis (sex cell formation) 55
• ( are for a survey of post GCSE students see
  notes)

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Tracing your ancestry

• A mutation of which of the following could be
  inherited from both your parents?
• a. Messenger RNA 20
• b. Nuclear DNA 29
• c. Ribosomal RNA 13
• d. Mitochondrial DNA 35
• ( are for a survey of post GCSE students see
  notes)

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Artificial Selection
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Manipulation of genes

• Genotype
• Phenotype selective breeding
• Manipulation of genes
• Biotechnology

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How genes work

• Inheritance
• Mutations
• Stem cells

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Genetic Engineering
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What do we need to do to genetically engineer
something?

• Location of genes
• Isolation of genes
• Removal of genes

• Transfer of genes
• Cultivation of genes

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Where do we go from here ?

• Dolly cloned from a mature cell by nuclear
  transfer
• Polly cloned from an embryo cell, but
  contains a human gene which produces the human
  protein in the sheeps milk
• Why are they scientifically significant?

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(No Transcript)
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What are the issues ?

• Monsanto monopoly
• 1998 Government moratorium on the growth of GM
  crops
• Media hype and scare mongering
• Human cloning designer babies

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So what do you think?
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So what do you really think?

• Should scientist be allowed to alter animal
  genes
• For medical reasons?
• For healthier or more efficient food production?
• For commercial reasons?

• Should scientists be allowed to alter Human
  genes
• For medical reasons?
• For commercial reasons?

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Recap

• What do genes do?
• Where do we find genes?
• What makes DNA so good as hereditary material?
• What information does DNA store?
• How does it store it?
• What happens next

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Protein (enzyme) Synthesis

• Key points
• Copy DNA
• Messenger RNA copy to site of synthesis
• Collect (Transfer RNA) selection of amino acids
  and arrange amino acids in correct sequence
• Builds a polypeptide chain ( protein)
• Several produced at one time
• Allows chemical reactions to take place in cell.

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Gene Expression

• Switching genes on and off
• Stem cells and mature differentiated cells
• Growth cell division and cell differentiation

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Gene Therapy

• Treatment of diseases by the introduction of
  powders containing working copies of the
  defective gene saturation approach
• Cystic Fibrosis
• Problems
• Disease is rare in the population
• Expensive to treat
• Research pressure into common ailments

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Genetic Engineering

• Transfer of genes from one species to another.
• How is it done?
• Gene Splicing
• Limitations can only add genes

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• http//www.food.gov.uk/gmdebate/aboutgm/?viewGM2
  0Microsite

Countries which are already growing some GM crops
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Concept map

• Compare building a house and cell?
• DNA, genes and enzymes
• Mitosis (cell division) and meiosis (sex)
• Phenotype and genotype recessive genes
• Growth cell division differentiation
• Mutation - natural and artificial
• GM debate and other issues

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Learning log

• Look at the questions where were your
  conceptual misunderstandings?