1. Parents can produce many types of offspring
Families will have resemblances, but no two are exactly alike
2. Every cell has a nucleus
Every nucleus has chromosomes
The number of chromosomes depends on the species
Ex. Humans have 46
3. GENES are located on chromosomes
genes control the TRAITS of the individual
genotype determines phenotype
4. Chromosomes come in matching sets
-these are called homologous pairs
Cells in your body have a complete set (all 46) - they are called DIPLOID
Sex cells (sperm and eggs) only have half (23) - they are called HAPLOID
FIND THE HOMOLOG!
When GAMETES combine, the ZYGOTE (offspring) gets half from mom (23) and half from dad (23)
ZYGOTES are diploid (46)
When sperm and egg meet, their chromosomes much match for the zygote to develop properly.
Let's Review Vocabulary.....
1. Matching sets of chromosomes are called ________ pairs
2. Egg and sperm combine to make a _______________
3. Egg and sperm are both known as _______________
4. A cell that only has half of a set of chromosomes is said to be _______________.
5. Genes are located on ___________________
It is similar to mitosis, but will produce 4 daughter cells that are each haploid.
Oogenesis - makes eggs (ovum)
Spermatogenesis - makes sperm
PROPHASE I of MEIOSIS
- homologous pairs form
-chromosomes trade genes,
Crossing-over increases the number of possible gene combinations