6.6 Gamete Formation and Genetic Variation
In humans, each gamete (egg and sperm) receives ___ chromosome from each of the ____ homologous pairs. Each chromosome separates _______.
1, 23, independently
The result of oogenesis is ____ large ___.
1, egg
The result of spermatogenesis is: ___ _____ of ____ size with ______ _____ content.
4, sperm, equal, different, genetic
Any 2 parents will produce a zygote with over ____ _________ (2^23 x 2^23) possible _____ combos.
70 trillion, diploid
Crossing Over: a ____ exchange between ______ chromosomes during ______ 1 of meiosis. This DNA exchange that occurs during crossing over increases ______. This makes the number of genetic combos ______.
DNA, homologous, Prophase, variation, infinite
What is gamete formation called?
Gametogenesis
In females: 1. _______L the process by which eggs are produced 2. A ______ cell increases in size to become a large immature cell called a germ cell. 3. There is _____ division of the ______ during egg production resulting in ____ egg and smaller _____ ______. These don't have enough cytoplasm to survive and are eventually _____ ______. 4. An egg contributes: _____, ____, and ____ to the embryo.
Oogenesis, diploid, uneven, cytoplasm, larger, polar bodies, broken down, DNA, nutrients, cytoplasm
The chromosome that each gamete receives is a matter of _____. As a result, a human gamete has 2^23 (___ million for EACH male and female) different chromosome ______ that can be produced by ______. (independent assortment)
chance, 8, combinations, meiosis
Meiosis contributes to genetic variation in 3 ways: ______ ________, _____ _______, and _______ ______.
independent assortment, random fertilization, crossing over
Random fertilization: the ____ of __ independently produced ______.
joining, 2, gametes
Independent Assortment: the ____ distribution of _______ chromosomes during meiosis.
random, homologous
The farther apart 2 genes are located on a chromosome, the more likely they are to be _____ by crossing over.
separated
In Males: 1. ___________: the process by which sperm are produced 2. A ______ cell increases in size to become and large immature cell called a _____ cell. 3. Male gametes form _______ that will allow the sperm to ____ to an egg and fertilize it. 4. Sperm only contribute ____ to the embryo.
spermatogenesis, diploid, germ, flagella, swim, DNA
Sexual reproduction creates _____ combinations of ___ that are essential for ______.
unique, genes, evolution
A ______ is formed when egg and sperm _____ join.
zygote, randomly