Heredity
BY :
SYAHRIANI
Do you Know them ?
Do they look like
one to each other ?
Do you see any ways that these children are
similar to their parents or brothers and sisters?
 Look around. Is anyone just like you?
You and everyone else are unique. No two
people are exactly alike, including ident...
Eye Color
Hair color
Hair Texture
Skin Color
Body Shape
So,what is heredity ?
 Heredity is the passing on of characteristics
from one generation to the next.
 It is the reason ...
Heredity and Genetics
Your genes determine whether or not you
possess certain physical traits. Your genes
make you blue ey...
Objective:
• The learner will realize that certain
characteristics are passed from parent to
offspring
What Exactly is a chromosome?
Chromosomes are the rod-
shaped, filamentous bodies present in the
nucleus, which become vis...
Organism No. chromosomes
• Human 46
• Chimpanzee 48
• Dog 78
• Horse 64
• Chicken 78
• Goldfish 94
• Fruit fly 8
• Mosquit...
Organism No. chromosomes
• Onion 16
• Mold 16
• Carrot 20
• Tomato 24
• Tobacco 48
• Rice 24
• Maize 20
• Haploppus gracil...
The size of the chromosomes in mitotic phase of animal
and plants sp generally varies between 0.5 µ and 32
µ in length, an...
• In order to understand chromosomes and their
function, we need to be able to discriminate among
different chromosomes.
•...
• Chromosomes may differ in the position of the
Centromere, the place on the chromosome
where spindle fibers are attached ...
• The centromere divides the chromosome into
two arms, so that, for example, an acrocentric
chromosome has one short and o...
What is a gene?
Definitions of the gene
• The gene is to genetics what the atom is to
chemistry.
• The gene is the unit of genetic informa...
How has the concept of a gene
developed in the minds of
geneticists?
Mendel (1866)
Inheritance is governed by “characters”
or “constant factors” that each controls
a phenotypic trait such as ...
What is so special about chromosomes ?
1.They are huge:
One bp = 600 dalton, an average chromosome is 107 bp
long = 109- 1...
DNA
(Deoxyribonucleic Acid)
Genetic material of cells…
• GENES – units of genetic material that CODES
FOR A SPECIFIC TRAIT
• Called NUCLEIC ACIDS
• DN...
DNA Nucleotide
O
O=P-O
O
Phosphate
Group
N
Nitrogenous base
(A, G, C, or T)
CH2
O
C1
C4
C3 C2
5
Sugar
(deoxyribose)
A HISTORY OF DNA
• Discovery of the DNA double helix
A. Frederick Griffith – Discovers that a factor in
diseased bacteria ...
Watson & Crick proposed…
•DNA had specific pairing between the
nitrogen bases:
ADENINE – THYMINE
CYTOSINE - GUANINE
•DNA w...
DNA Double Helix
Nitrogenous
Base (A,T,G or C)
“Rungs of ladder”
“Legs of ladder”
Phosphate &
Sugar Backbone
DNA Double Helix
P
P
P
O
O
O
1
2
3
4
5
5
3
3
5
P
P
P
O
O
O
1
2 3
4
5
5
3
5
3
G C
T A
Nitrogenous Bases
• PURINES
1. Adenine (A)
2. Guanine (G)
• PYRIMIDINES
3. Thymine (T)
4. Cytosine (C) T or C
A or G
Chargaff’s Rule
• Adenine must pair with Thymine
• Guanine must pair with Cytosine
• Their amounts in a given DNA molecule...
BASE-PAIRINGS
CG
H-bonds
T A
Genetic Diversity…
• Different arrangements
of NUCLEOTIDES in a
nucleic acid (DNA)
provides the key to
DIVERSITY among liv...
The Code of Life…
• The “code” of the chromosome is the SPECIFIC
ORDER that bases occur.
A T C G T A T G C G G…
DNA is wrapped tightly around histones
and coiled tightly to form chromosomes
See p. 297
DNA Replication
• DNA must be copied
• The DNA molecule produces 2
IDENTICAL new complementary
strands following the rules...
DNA Replication
• Semiconservative
Model:
1. Watson and Crick
showed: the two strands of
the parental molecule
separate, a...
Hereditas
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Hereditas

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Hereditas

  1. 1. Heredity BY : SYAHRIANI
  2. 2. Do you Know them ? Do they look like one to each other ?
  3. 3. Do you see any ways that these children are similar to their parents or brothers and sisters?
  4. 4.  Look around. Is anyone just like you? You and everyone else are unique. No two people are exactly alike, including identical twins. However, many of your traits are inherited.  People in a family may have things in common. They can share traits.  Through heredity, living things inherit traits from their parents. Traits are physical characteristics. You resemble your parents because you inherited your hair and skin color, nose shape, height, and other traits from them. 
  5. 5. Eye Color
  6. 6. Hair color
  7. 7. Hair Texture
  8. 8. Skin Color
  9. 9. Body Shape
  10. 10. So,what is heredity ?  Heredity is the passing on of characteristics from one generation to the next.  It is the reason why offspring look like their parents. It also explains why cats always give birth to kittens and never puppies.  The process of heredity occurs among all living things including animals, plants, bacteria, protists and fungi.  The study of heredity is called genetics and scientists that study heredity are called geneticists.
  11. 11. Heredity and Genetics Your genes determine whether or not you possess certain physical traits. Your genes make you blue eyed or brown eyed, or have brown or blond hair. These traits are highly complex, and involve the interaction of many genes.
  12. 12. Objective: • The learner will realize that certain characteristics are passed from parent to offspring
  13. 13. What Exactly is a chromosome? Chromosomes are the rod- shaped, filamentous bodies present in the nucleus, which become visible during cell division. They are the carriers of the gene or unit of heredity. Chromosome are not visible in active nucleus due to their high water content, but are clearly seen during cell division.
  14. 14. Organism No. chromosomes • Human 46 • Chimpanzee 48 • Dog 78 • Horse 64 • Chicken 78 • Goldfish 94 • Fruit fly 8 • Mosquito 6 • Sequoia 22 • Round worm 2
  15. 15. Organism No. chromosomes • Onion 16 • Mold 16 • Carrot 20 • Tomato 24 • Tobacco 48 • Rice 24 • Maize 20 • Haploppus gracilis 4 • Crepis capillaris 6
  16. 16. The size of the chromosomes in mitotic phase of animal and plants sp generally varies between 0.5 µ and 32 µ in length, and between 0.2 µ and 3.0 µ in diameter. The longest metaphase chromosomes found in Trillium - 32 µ. The giant chromosomes found in diptera and they may be as long as 300 µ and up to 10 µ in diameter. In general, plants have longer chromosomes than animal and species having lower chromosome numbers have long chromosomes than those having higher chromosome numbers Among plants, dicots in general, have a higher number of chromosome than monocots. Chromosomes are longer in monocot than dicots.
  17. 17. • In order to understand chromosomes and their function, we need to be able to discriminate among different chromosomes. • First, chromosomes differ greatly in size • Between organisms the size difference can be over 100-fold, while within a sp, some chromosomes are often 10 times as large as others. • In a species Karyotype, a pictorial or photographic representation of all the different chromosomes in a cell of an individual, chromosomes are usually ordered by size and numbered from largest to smallest.
  18. 18. • Chromosomes may differ in the position of the Centromere, the place on the chromosome where spindle fibers are attached during cell division. • In general, if the centromere is near the middle, the chromosome is metacentric • If the centromere is toward one end, the chromosome is acrocentric or submetacentric • If the centromere is very near the end, the chromosome is telocentric.
  19. 19. • The centromere divides the chromosome into two arms, so that, for example, an acrocentric chromosome has one short and one long arm, • While, a metacentric chromosome has arms of equal length. • All house mouse chromosomes are telocentric, while human chromosomes include both metacentric and acrocentric, but no telocentric.
  20. 20. What is a gene?
  21. 21. Definitions of the gene • The gene is to genetics what the atom is to chemistry. • The gene is the unit of genetic information that controls a specific aspect of the phenotype. • The gene is the unit of genetic information that specifies the synthesis of one polypeptide.
  22. 22. How has the concept of a gene developed in the minds of geneticists?
  23. 23. Mendel (1866) Inheritance is governed by “characters” or “constant factors” that each controls a phenotypic trait such as flower colour.
  24. 24. What is so special about chromosomes ? 1.They are huge: One bp = 600 dalton, an average chromosome is 107 bp long = 109- 1010 dalton ! (for comparison a protein of 3x105 is considered very big. 2. They contain a huge amount of non- redundant information (it is not just a big repetitive polymer but it has a unique sequence) . 3. There is only one such molecule in each cell. (unlike any other molecule when lost it cannot be re-synthesized from scratch or imported)
  25. 25. DNA (Deoxyribonucleic Acid)
  26. 26. Genetic material of cells… • GENES – units of genetic material that CODES FOR A SPECIFIC TRAIT • Called NUCLEIC ACIDS • DNA is made up of repeating molecules called NUCLEOTIDES
  27. 27. DNA Nucleotide O O=P-O O Phosphate Group N Nitrogenous base (A, G, C, or T) CH2 O C1 C4 C3 C2 5 Sugar (deoxyribose)
  28. 28. A HISTORY OF DNA • Discovery of the DNA double helix A. Frederick Griffith – Discovers that a factor in diseased bacteria can transform harmless bacteria into deadly bacteria (1928) B. Rosalind Franklin - X-ray photo of DNA. (1952) C. Watson and Crick - described the DNA molecule from Franklin’s X-ray. (1953) SEE p. 292-293
  29. 29. Watson & Crick proposed… •DNA had specific pairing between the nitrogen bases: ADENINE – THYMINE CYTOSINE - GUANINE •DNA was made of 2 long stands of nucleotides arranged in a specific way called the “Complementary Rule”
  30. 30. DNA Double Helix Nitrogenous Base (A,T,G or C) “Rungs of ladder” “Legs of ladder” Phosphate & Sugar Backbone
  31. 31. DNA Double Helix P P P O O O 1 2 3 4 5 5 3 3 5 P P P O O O 1 2 3 4 5 5 3 5 3 G C T A
  32. 32. Nitrogenous Bases • PURINES 1. Adenine (A) 2. Guanine (G) • PYRIMIDINES 3. Thymine (T) 4. Cytosine (C) T or C A or G
  33. 33. Chargaff’s Rule • Adenine must pair with Thymine • Guanine must pair with Cytosine • Their amounts in a given DNA molecule will be about the same. G CT A
  34. 34. BASE-PAIRINGS CG H-bonds T A
  35. 35. Genetic Diversity… • Different arrangements of NUCLEOTIDES in a nucleic acid (DNA) provides the key to DIVERSITY among living organisms.
  36. 36. The Code of Life… • The “code” of the chromosome is the SPECIFIC ORDER that bases occur. A T C G T A T G C G G…
  37. 37. DNA is wrapped tightly around histones and coiled tightly to form chromosomes See p. 297
  38. 38. DNA Replication • DNA must be copied • The DNA molecule produces 2 IDENTICAL new complementary strands following the rules of base pairing: A-T, G-C •Each strand of the original DNA serves as a template for the new strand See p. 298
  39. 39. DNA Replication • Semiconservative Model: 1. Watson and Crick showed: the two strands of the parental molecule separate, and each functions as a template for synthesis of a new complementary strand. . Parental DNA DNA Template New DNA

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