Download Reproduction and Genetics Notes

Reproduction and Genetics Notes
1. Reproduction: the process of producing offspring (Babies).
2. Asexual reproduction: reproduction in which a single parent produces offspring that are
genetically identical to it’s self.
i. This type of reproduction does not involve the union of gametes.
b. Advantages - fast, can produce large numbers of offspring very quickly.
c. Disadvantages: no genetic variations, the offspring are genetically identical to the
parent
Examples:
3. Binary fission: Asexual reproduction where organisms such as bacteria or ameba’s simply
spit and divide.
4. Fragmentation: Type of asexual reproduction where body parts that are broken off re-grow
missing parts.
a. Sea stars will grow new arms, Lizards can regrow a new tail
5. Budding: Type of asexual reproduction where a parent will grow a new organisms on it own
body, which pinches off.
a. Hydra reproduce by budding
b. Potatoes and other plants can grow a new plant for it’s root
c. Aspen trees send up cheater plant from the roots
d. Cuttings from plants
6. Parthenogenesis: Process where females make eggs that will grow into babies without
being fertilized.
a. Triops (three eyed shrimp)
b. Whiptailed lizards, Lupin Aphid or Burmese python
7. Sexual reproduction: reproduction in which gametes from two parents unite.
a. Advantages; creates genetic variation. The offspring are different from the parents
and each other.
b. Disadvantages; it is slow and takes lots of energy. It takes a long time to
reproduce, make babies and raise them to adult hood.
Examples
c. Animals giving birth to babies. (Animals the have males and females. Anything
that uses sperm and eggs)
d. Plants with flowers making seeds
8. Gametes: a haploid reproductive cell that unites with another haploid reproductive cell to
form a zygote. All so known as Reproductive Cells or Sex Cells
a. Examples
i. Sperm: Gametes or sex cells produced by males
1. Pollen: male sex cell in plants
2. Sperm is produced by germ cells in organs called Testis
ii. Ova: (Eggs) Gamete or Reproductive cells produced by females.
1. Eggs or Ova are produced by germ cells in organs called Ovaries
b. Haploid Cells: Gametes are haploid cells which means they have half as many
chromosomes as normal cell or Diploid cell
c. Gametes or sex cells are produce by a cell division process called Meiosis.
9. Meiosis: a process in cell division during which the number of chromosomes decreases to
half the original number, which results in the production of sex cells.
a. Peoples normal diploid body cell has 46 chromosomes (two sets of 23)
b. Peoples normal haploid sex cells have 23 chromosomes
c. Don’t get meiosis confused with mitosis.
i. Mitosis: a process of cell division that forms two new nuclei, each of which
has the same number of chromosomes
ii. Mitosis makes body cells
Chromosomes and Genes Notes
10. Germ Cells: Cells that are specialized for sexual reproduction are called germ cells. Only
germ cells can produce gametes.
a. Gametes are haploid cells which means they have half as many chromosomes as
somatic cells (body cells).
People body cells have 46 chromosomes.
Their gametes have 23 chromosomes
Frog body cells have 26 chromosomes.
Their gametes have 13 chromosomes
Dog body cells have 78 chromosomes.
Their gametes have 39 chromosomes
11. Somatic Cells: Other body cells are called somatic cells. Somatic cells do not participate in
sexual reproduction.
a. Somatic cells or body cells are diploid cells. They have twice as many
chromosomes as do sex cells
12. Chromosomes: Long skinny structure made of DNA found in the nucleus of eukaryotic cells
a. Chromosomes contain the genes. Chromosomes are a chain of Genes.
Chromosome = Gene chain
13. Gene: the unit of heredity; a segment of DNA that codes for a protein or trait
a. One chromosome can contain 1000’s of genes
b. People have 46 chromosomes that contain 100,000 gene pairs
c. An organism must have exactly the right number of chromosomes. If an organism
has too many or too few chromosomes, the organism may not develop and
function properly.
14. Sex Determination and Chromosomes (Why
are boys, boys and girls, girls)
a. Sex chromosomes have genes that determine
the sex of an individual.
i. Females (Girls) have two sex
chromosomes (XX)
ii. Males (Boys) have two sex
chromosomes (XY)
iii. Sex Chromosomes = the 23rd pair of
chromosomes
b. Autosomes are chromosomes with genes that
do not determine the sex of an individual.
i. Autosomes = chromosome 1 - 22
c. Karyotype: Chart that shows the chromosomes of a cell. (Can you use this karyotype to
determine if the cell belonged to a female or male?
15. How did our life get started?
or
or What is the diploid life cycle?
Where do babies come from?
a. 1st - The gametes, the sperm and the egg, join during fertilization.
The result is a diploid zygote.
b. 2nd - This single diploid cell goes through mitosis and eventually
grows into a baby and the baby is born are hatched.
c.
3rd - The baby grows to an adult.
d. 4th - Germ cells of a multi-cellular adult organism undergo
meiosis and form haploid gametes or sex cells. (sperm and
egg cells)
Gamete formation
16. Spermatogenesis is the process by which male gametes form.
a. Male germ cells under go meiosis to form four haploid cells. These cells change in form
and develop a tail to form sperm cells.
17. Oogenesis is the production, growth, and maturation of an egg, or ovum.
a. Female germ cells under go meiosis to form haploid sex cells. During the cytokinesis the
cytoplasm is divided unequally creating a smaller and larger cell. The smaller cells are called
polar bodies and will die.
i. Oogenesis form only one haploid cell that will live called an Ovum or egg. The other
three cells are called polar bodies and will die.