1. Genetics-Chapter 10

2. What is inheritance and genetics?
Offspring receiving traits from parent(s)
Genetics
The scientific study of heredity

3. Gregor Mendel Mendel studied seven different pea plant traits
Origin of Genetics
Gregor Mendel
Mendel studied seven different pea plant traits

4. What are traits?
Characteristics that are inherited from parents. (Like seed color or shape)

5. Origin of Genetics

6. Origin of Genetics

7. What was Mendel’s Experiment?
Mendel crossed plants with their alternate type and studied their offspring.
The two parent plants (P generation) produce the F1 generation of hybrids
Crossing the F1 plants produce the F2 generation

8. The P Cross

9. The F1 Cross

10. What was Mendel’s Conclusions?
1st
Biological inheritance determined by “factors” that are passed from one generation to the next.
Today well call those factors…..
GENES!

11. Mendel’s Conclusions

12. Mendel’s Conclusions 2nd
Mendel’s second conclusion was the principle of dominance
This principle states that some alleles are dominant and others are recessive

13. What are Alleles?
Each trait that Mendel studied was controlled by ONE gene with TWO contrasting forms (i.e. tall vs. short).
The different forms of the gene are call alleles.
Represented by letters.

14. What is the Principle of Segregation?
To explain the F1 cross, Mendel formed the principle of segregation which states that recessive alleles separate from dominant ones during gamete formation

15. What is the law of independent assortment?
Mendel’s second law states that genes for different traits are inherited independently of each other.
Example: seed color and seed shape.

16. What is hetero and homozygous?
If a mix of two different alleles (Tt), then organism called HETEROZYGOUS (hetero—different)
If two of the same alleles (TT, or tt), then HOMOZYGOUS (homo-same)

17. What is dominant and recessive?
One gene = one trait
One gene form (allele) dominates the expression of the other
Dominant is represented by capital letter T, while recessive is represented by lower case letter.
Tt= Tall pea plant
TT, Tt, tt = GENOTYPE (set of alleles or letters)
Tall or short = PHENOTYPE (physical characteristic that is expressed)

18. What are punnett squares?
Developed in 1905 by English biologist Reginald Punnett.
Shorthand way of finding the expected proportions of possible genotypes in the offspring of a cross.
Each parent’s genotype is
needed in order to
complete the square.

19. Punnett Squares Mono crosses occur when you are considering one trait
Di crosses occur when you are considering two traits

20. Mendel Vocab Terms
Hybrid
Fertilization
Zygote
Pollination

21. What is Meiosis?

22. Meiosis The cellular process of producing gametes (sex cells).
Female sex cell is called an egg
Male sex cell is called a sperm.

23. Vocabulary Define the following terms Gamete Diploid Haploid
Crossing Over
Genetic recombination
Polyploidy

24. Meiosis-Chapter 11

25. Meiosis I
Is exactly like mitosis only each phase is labeled with a 1 behind it.
In each step of meiosis 1 the exact thing happens as in Mitosis.
Pro 1-chromosomes appear and nuclear envelope disappears
Meta 1-chromosomes line up in the middle
Ana 1-chromosomes are pulled apart (chromatid)
Telo 1-chromatids reach opposite ends and nuclear envelope reappears.
The DNA was copied during interphase also

26. Meiosis-Chapter 11

27. Meiosis 2 No copying of DNA before Prophase begins.
Cycles back through except the chromatids are separated instead of chromosomes.
Leads to four gametes with ½ the amount of DNA/chromosomes as a normal cell.
Haploid cell

28. What is the purpose of Meiosis?
Meiosis produces gametes (sex cells)
Sex cells are then united to create offspring. These offspring carry on the species existence.
If the species dies out (extinction).

29. Crossing Over and Random Assortment

30. What is Nondisjunction?
Chromosome fail to separate properly during meiosis

31. Nondisjunction
Can result in Trisomy 21 (Down’s Syndrome = extra chromosome 21)

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