Chapter+Homework

Human Life Cycle 16.1 p. 320 INSERTING FIGURES IS ALWAYS A GOOD THING. (1) How many chromosomes does a mother contribute to a new individual? A father? Both the sperm and the eggs contain 23 chromosomes and when they both unite, they come togather in the egg and have a total of 46. (2) Where does meiosis occur in males? in females? For males meiosis takes place in the testes during the process that the sprem is being made, and for females it takes place in the ovaries during the process of eggs being made. (3) Compare and egg cell to a sperm cell. Sprem is smaller than the egg, sperm only carries chromosomes on its way to the egg. Once it reaches the egg, then the egg does the rest and creates the first cell of a baby called the zygote. The Zygote is where all 46 chromosomes come togather and make one baby. (4) What is the difference between meiosis and mitosis. Mitosis is the process of copying the 23 chromosomes to the sperm for delivery to the eggs. Meiosis is the process taking place in either the testes or ovaries where 46 chromosomes are reduced to 23 chromosomes.

Development Chapter 17 17.1 (5) Describe in detail how fertilization occurs This is the process where the sprem and the egg come togather to create a Zygote. The Zygote is the first cell in a long drawn out process of creating a baby. (6) What is polyspermy and how is prevented during fertilization? The is the enterance of more than one sperm into the ovarie. The egg has its own defence system that uses plasma membrane. As soon as the egg recieves a sperm the plasma membrane shuts down the egg's ability to attrace more sperm. 17.2 (7) Describe the processes involved in development. There are 4 stages of development that occur. Clevage, Growth, Morphogenesis, and Differentiation. (8) What are the extraembryonic membranes and what is their role? They hang out outside the embryo. They are envolved in the process of making sure that the new fetus gets enough nourishment in order to live and be able to survive. (9) What happens during pre-emrbyonic development? This takes place right after fertilization and is active during the first week of pregnancy. (10) What happens during embryonic development? Takes place at the end of the first week and doesn't stop untill the end of the second month of development. This is when the embryo embeds its self into the urterus wall. (11) What are the primary germ layers and what body structures come from each layer? The Ectoderm ( outer layer) The Mesoderm (middle layre) The Endoderm (inner layre)