1. Understanding Genetics
Unit 2

2. Of your family members who do you feel you act like, look like, etc.?
Bell Ringer October 19th , 2011
Of your family members who do you feel you act like, look like, etc.?

3. Heredity
The biological process by which certain traits are transmitted from parents to their children
Genetics
The study of how traits are passed from parents to child through heredity

4. It all starts with…. Chromosomes
Long, threadlike structures in the nucleus or central portion, of each human cell

5. CYTOPLASM: Substance of a cell outside of the nucleus
CELL: Basic unit of all living matter (Adult = over 10 trillion cells)
CYTOPLASM: Substance of a cell outside of the nucleus
NUCLEUS: Central point of cell / contains genetic coding for maintaining life systems and issuing commands for growth & reproduction
CHROMOSOMES:
46 in each Nucleus (23 pairs)
GENES: bands on chromosomes (thousands of genes)
DNA on genes (billions of DNA)

6. GENES On each chromosome there are hundreds or thousands of genes
Hereditary unit that determines a particular trait

7. T
2. _______ Genes carry inherited traits that are passed on from generations to generations. Hundreds of thousands of genes, which make up the traits of human beings, are carried on every chromosome.

10. Dominant and Recessive traits
What happens when one parent carries the trait for blue eyes and one carries the trait for brown eyes?
Dominant
Stronger trait
Recessive
Weaker trait

11. Heterozygous (hybrid):
having dissimilar pairs of alleles for any hereditary characteristic Rr
Homozygous (purebred)
: having identical pairs of alleles for any given pair of heredity characteristics
RR, rr

12. T
4. _______ Dominant genes are stronger genes and recessive genes are weaker.

13. T DOMINANT RECESSIVE Brown hair Other Color hair Brown eyes
Straight hair line
Free Earlobes
Roll Tongue
Second finger shorter then the 4th
Hitchhiker’s thumb T
5. _______ In the formation of a new individual where the genes are both recessive and dominant, the dominant will overpower.
RECESSIVE
Blonde hair
Red hair
Blue Eyes
Widows peak
Attached earlobes
Can’t roll tongue
Interlock hands and right thumb on top
No hitchhiker’s thumb

14. Dominant vs. Recessive widow’s peak Unattached earlobe Short fingers
Continuous hairline
Unattached earlobe
Attached earlobe
Short fingers
Long fingers
Freckles
Lack of freckles

15. Punnett Square

16. T BB Bb bB bb Wife B Wife b Husband B Husband b
Determine the chances of passing on a genetic trait in the following situation:
The wife is blue-eyed and carries genes for blue eyes on both of the chromosome pairs. The husband is brown eyed and carries a gene for brown eyes on one of the pairs and a gene for blue eyes on he other one of the pairs. Complete the following grid to determine the chances for each of their children to be born with blue or brown eyes.
B = dominant brown gene b = recessive blue gene
There is a _____________________ in four chance that the child will have brown eyes and carry a gene for blue eyes.
There is a _____________________ in four chance that the child will have blue eyes and carry genes for only blue eyes.
6. _______ It is probable that a dominant brown-eyed mother and a recessive blue-eyed father will have a brown-eyed child.
Wife B
Wife b
Husband B
Husband b BB Bb bB bb

17. Red Hair and blue –green eyesT
7. _______ It is probable that a child can have recessive light colored hair even though both of his parents have dominant dark colored hair.
Red Hair and blue –green eyes

18. Recessive (weaker) genes will not produce the characteristic unless transmitted by both parents.

19. Gender Determination Females:XX Males: XY
Gender is determined by the male

20. Multiple Births Fraternal Twins:
The ovary releases two separate eggs and each is fertilized by a different sperm cell.
Can be boy and girl
Do not look exactly alike
Identical twins
A single egg is fertilized and then splits into two
Both boys or girls
Look very much alike

21. MULTIPLE BIRTHS

22. F like siblings. identical
12. _______ Fraternal non-identical multiple births that come from two different eggs will look
like siblings.
identical

23. F
13. _______ Identical multiple births that come from one fertilized egg
can be different sexes.
will be the same sex.

24. F
14. _______
are when the ovum splits apart but the separation is not complete.
Double jointed twins
Conjoined twins

25. CONJOINED TWINS Conjoined twins result when
a fertilized ovum begins to
split into two parts, but does
not fully complete the
process. The babies are joined
at whatever location does
not complete the splitting
process.

26. Genetic Disorders
Medical conditions caused by errors in genes or chromosomes
Down syndrome
Cystic fibrosis
Muscular dystrophy
Sickle cell disease
Tay- sachs disease
PKU

27. Activity
Genetic Gamble

28. Genetic Counseling
Genetic counselors help provide families with the information they need to understand genetic disorders.

29. Activity: Gene O Gram