The document provides an overview of genetics and inheritance. It discusses Gregor Mendel's experiments with pea plants that demonstrated dominant and recessive genes and the inheritance patterns of traits. The document also summarizes different patterns of inheritance such as incomplete dominance, co-dominance, and sex-linked traits. It explores chromosomal abnormalities and mutations that can occur. Finally, the document discusses evidence that supports the theory of evolution such as the fossil record, comparative anatomy and embryology.

1. INHERITANCE AND
CHANGE:
DNA
¤
CHARACTERISTICS AND
INHERITANCE
Compiled by:
Madre’ Nortje
BIOLOGY

2. A BRIEF INTRODUCTION TO GENETICS
S C I E N C E G R A D E 1 0 / D N A 2
A Brief Introduction to Genetics is a short
documentary film created using motion
graphics as the main visual component. It is a
film that explores the history of genetics &
genomics and the... 823 views since Aug 15,
2010
submitted by: dmetzky
ASSIGNMENT GOOD WEB PAGE:
http://www.genomebc.ca/education/

3. A BRIEF INTRODUCTION TO GENETICS
HTTP://WWW.SCIVEE.TV/NODE/20869
S C I E N C E G R A D E 1 0 / D N A 3
http://www.scivee.tv/node/20869

4. CHARACTERISTICS AND
INHERITANCE
S C I E N C E G R A D E 1 0 / D N A 4
HOMOLOGOUS
• An organ that is similar to
another in: structure, function,
position and development.

5. HOMOLOGOUS
• After the fusion of the egg and sperm the
chromosomes in the zygote now exist as 23 pairs. 23
from each sex cell.
• Homologous chromosomes exist as they have the
same genes for particular characteristics at the same
location on the chromosomes.
• The zygote has two genes for each characteristic –
one from each parent.
S C I E N C E G R A D E 1 0 / D N A 5

6. GREGOR MENDEL 1822 -1884
“FATHER OF GENETICS”
www.dobermann-review.com
S C I E N C E G R A D E 1 0 / D N A 6

7. Mendel Pea Theory
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 www.schools-wikipedia.org
•Pure breeding means that parents produce
offspring off same colour only.

8. Mendel Pea Theory
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 www.scq.ubc.ca

9. GENETIC PEAS
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 Gene controlling the colour
 Pea plants with the alternate alleles
 CG dark green – incompletely dominant
 CY yellow – defective chlorophyll
– unable to photosynthesize – die
 youngGenetic-Coding.gif
 200 × 349 - ... insight into the DNA of the pea, by unravelling its genetic coding.
 www.topnews.in
www.topnews.in

10. GENETIC PEAS TYPE
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•GENOTYPE
PHENOTYPE
•CG CG Dark green
•CG CY Light green
•CY CY Yellow
•Plants grown from Genotype CGCY X CGCY
•Pea plants are self fertilizing – cross giving
rise to Genotype seed
CG CG : 2CG CY : CY CY

11. GENETIC BARLEY
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 Gene controlling pigment
 Producing the alternate alleles
 A: Pigment produced – green (dominant)
 ‘a: No pigment – albino / or white
(recessive)
www.southernbiological.com

12. GENETIC BARLEY TYPE
http://www.albertabarley.com/barley
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Science grade 10/DNA
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 Plants grown from Genotype Aa x Aa
 Germinated seeds, can grow into
 AA – green
 Aa – green
 Aa – albino / white

 Plants obtained ratio –
 3 green: 1 white

13. CHARACTERISTICS AND INHERITANCE
DOMINANT AND RECESSIVE GENES
• PEDIGREE PURE BREEDING:
•Family trees, showing the inheritance of particular
characteristics from one generation to later
generations.
• DOMINANT GENE
•A gene for a particular characteristic that
completely hides or masks the alternative
(recessive) gene.
S C I E N C E G R A D E 1 0 / D N A 13

14. CHARACTERISTICS AND INHERITANCE
DOMINANT AND RECESSIVE GENES
• RECESSIVE GENE
•A gene for a particular characteristic that is
completely hidden or masked by the alternative
(dominant) gene
• ALLELES OF GENES
•Alleles (a-LEELs): different forms of the same
gene; each allele produces variations in inherited
characteristics, e.g. eye colour
S C I E N C E G R A D E 1 0 / D N A 14

15. • HOMOZYGOUS
•Homozygous (HO-mo-ZYE-gus): where the genes for
particular characteristic are the same; a pure breeder
• HETEROZYGOUS
•Heterozygous (HET-er-o-ZYE-gus): where the genes
for a particular characteristic are different; a hybrid
S C I E N C E G R A D E 1 0 / D N A 15
CHARACTERISTICS AND INHERITANCE
DOMINANT AND RECESSIVE GENES

16. DOMINANT AND RECESSIVE GENES
• The RR and rr combinations of alleles
where the offspring is identical to parent
are HOMOZYGOUS
• The Rr combinations of alleles is known
as HETEROZYGOUS.
S C I E N C E G R A D E 1 0 / D N A 16

17. S C I E N C E G R A D E 1 0 / D N A 17

18. OTHER PATTERNS OF INHERITANCE
S C I E N C E G R A D E 1 0 / D N A 18
THE DETERMINATION OF OUR PHYSICAL CHARACTERISTICS IS
COMPLEX
THREE FORMS:
1. INCOMPLETE DOMINANCE
• GENOTYPE
•Genotype (JEE-no-type): the type of genes possess in
an organism (BB, BW and WW) for specific
characteristic (pg. 131 – Black, White or Blue – grey
feathers)
• PHENOTYPE
•Phenotype (FEE-no-type): the physical appearance or
characteristics of an organism (pg. 131 – the colour
Black, White or Blue – grey)

19. .
INCOMPLETE DOMINANCE
some genes do not have dominant or recessive alleles and
results in a heterozygous individual (blended)
e.g. black-feathered (BB) and white-feathered (WW)
chickens mating to create a blue/grey-feathered (BW)
offspring
The terms BB, WW and BW are called genotypes.
The physical characteristic (feather colour) is called the
phenotype
S C I E N C E G R A D E 1 0 / D N A 19
OTHER PATTERNS….NOT ALL GENES ARE
INHERITED AS SIMPLE RECESSIVE OR
DOMINANT GENES

20. OTHER PATTERNS OF INHERITANCE
S C I E N C E G R A D E 1 0 / D N A 20
THREE FORMS continue:
2. CO – DOMINANCE
• BOTH OFFSPRING ARE EXPRESSED IN THE
PHENOTYPE – e.g. Blood groups
www.biologycorner.com

21. CO – DOMINANCE ON HAND OF BLOOD TYPE
Some cases have both alleles in the heterozygous
offspring expressed in the phenotype
E.g. – blood type
Three alleles for blood type gene and the types A, B,
O and AB exist
AB can form both A or B and has characteristics of
both A and B but is not a blend
A and B are dominant to O thus O will only occur in
OO homozygous individual
S C I E N C E G R A D E 1 0 / D N A 21

22. OTHER PATTERS OF INHERITANCE
S C I E N C E G R A D E 1 0 / D N A 22
THREE FORMS continue:
3. SEX – LINKING / SEX DETERMINATION
•Chromosomes: objects found in the nucleus of a cell that
carry the genetic information
• SEX CHROMOSOMES
• XX - female
• XY - male
• AUTOSOMES
• All other chromosomes are referred to as autosomes

23.  X and Y chromosomes
 The only two
chromosomes that
determine what sex you
will be
 All other chromosomes
are referred to as
autosomes
 XX - female
 XY - male
S C I E N C E G R A D E 1 0 / D N A 23
X & Y
♀
♂

24. ALLELE FOR COLOUR-BLINDNESS:
S C I E N C E G R A D E 1 0 / D N A 24
X
CHROMOSO
ME

25. DIFFERENCE
FEMALE
• Eggs will have
23 chromosomes
one of which will
be X
MALE
• Sperm will have
23 chromosomes,
but half of the
sperm carry X
chromosome and
the other half
carry Y
chromosome
S C I E N C E G R A D E 1 0 / D N A 25

26. FERTILISATION: ♂ MALE →♀
If a male sperm….
 Containing X fertilizes an egg
 female (XX)
Containing Y fertilises and egg
 male (XY)
S C I E N C E G R A D E 1 0 / D N A 26

27. SEX LINKAGE
Sex-linked genes - found on X
chromosome and not on Y and vice
versa.
E.g.:
Colour blindness
Haemophilia
Duchenne’s muscular dystrophy
S C I E N C E G R A D E 1 0 / D N A 27

28. S C I E N C E G R A D E 1 0 / D N A 28

29. CHROMOSOMAL ABNORMALITIES
• MUTATION
• Permanent changes in genes, they may be caused
by exposure to a →
• MUTAGEN
• Something that causes a mutation
• KNOWN MUTAGENS
• UV radiation
• X – Ray
• Agricultural and Industrial Chemicals
S C I E N C E G R A D E 1 0 / D N A 29

30. HANDOUTS TO BE COMPLETE –
HAND BACK ON TUESDAY NEXT WEEK
1.Questions: How to find Your Learning Style
2. Online Questionnaire on Learning Styles
http://www.engr.ncsu.edu/learningstyles/ilsweb.html
3. How to make your own DNA Code Bracelet
S C I E N C E G R A D E 1 0 / D N A 30

31. You all NOW have the GREAT Opportunity to
learn more about genetic disorders
YOUR BIOLOGY
Assignment!!!!
Test what you know?
Questions 2.2 p 135
S C I E N C E G R A D E 1 0 / D N A 31
HOMEWORK:
QUESTIONS 2.2 -
P135

32. NATURAL SELECTION
 Selection of certain characteristics for
survival in nature
 Organisms possess structural, functional
and behavioural characteristics that enable
them to survive in their environments
 Those that do not are less likely to survive
and thus less likely to reproduce and not
pass on those weaknesses
Science grade 10/DNA 8/06/2011
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33. Just means change.
Also the name given to the process whereby
new life forms develop
Influenced by such things as physical barriers
(mountains, rivers, oceans) known as
geographic isolation
EVOLUTION
Science grade 10/DNA 8/06/2011
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34. EVOLUTION
 If a species is separated by
such, they may develop
different adaptation so much
so that they can no longer
interbreed
 This is referred to as
Speciation
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EVOLUTIO
N

35. EVOLUTION
 Best summarised in 5 points
1. Variation exists within any population of
organisms
2. All organism face a daily struggle to
survive and reproduce, whether to find
mates, seek shelter/food, escape
predators
3. Those that are best able to survive and
reproduce will do so
Science grade 10/DNA 8/06/2011
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36. EVOLUTION
4. Those that reproduce pass on the
advantageous characteristics to their offspring
5. Over time, the population will become better
suited to its environment
 The theory of evolution can explain how plants
and animals have gradually changed into new,
different kinds over long periods of time
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37. SUMMARY Questions
Science grade 10/DNA 8/06/2011
37

38. But remember….
So what
is the
evidence
for
Evolution
??
 If an environment changes too
rapidly and the genes required for
survival in the changed environment
are not present in the gene
pool….EXTINCTION may occur.
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39. FOSSIL EVIDENCE
• Study of skeletal structure from fossils
• Evidence of locations
• Evidence of past environments
Science grade 10/DNA 8/06/2011
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40. But remember…. Fossils.....
So what
is the
evidence
for
Evolution
??
Science grade 10/DNA 8/06/2011
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41. Comparative Embryology
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• In certain stages of
development, embryos of
organisms in the same
group e.g. vertebrates,
have similar structures
(a) pig
(b) cow
(c) Rabbit
(d) human

42. COMPARATIVE ANATOMY
S C I E N C E G R A D E 1 0 / D N A 42

43. DESIGN OF EXPERIMENT:
STEPS TO FOLLOW - CLEAR AND SIMPLE P 20 GRADE 8
S C I E N C E G R A D E 1 0 / D N A 43
EXPERIMENT
Title
Aim
Hypothesis
Variables Control
Material
METHOD
Tables &
Drawings
Observation RESULTS
Discussion EVALUATION
Conclusion

44. REVISION: SCIENCE ALPHA TABLE(I)
DATE UPDATED: 18/05/2011
S C I E N C E G R A D E 1 0 / D N A 44
Word Meaning
A Atmosphere
B
C Carbon Dioxide
C Catalyst
is a chemical that alters the rate of a chemical
reaction but is not consumed by the reaction
C Chemical Equation Reactions are described by
C Concentration
D Dry Ice
E
F Fermenting
G Gas e.g. X 3
H Hydrogen
H Hypothesis
I
J

45. REVISION: SCIENCE ALPHA TABLE (II)
DATE UPDATED: 18/05/2011
S C I E N C E G R A D E 1 0 / D N A 45
Word Meaning
K
L
M
N
O Observation
O Oxygen
P Photosynthesis
P Precipitate
Q
R Respiration Rate
R
S

46. REVISION: SCIENCE ALPHA TABLE (III)
DATE UPDATED: 18/05/2011
S C I E N C E G R A D E 1 0 / D N A 46
Word Meaning
O Observation
O Oxygen
P Photosynthesis
P Precipitate
Q
R Respiration Rate
R
S
T
U
V Variable
W
X
Y
Z