Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing

From the energy stored in food substance( glucose) as Chemical energy to the energy of motion,which is Kinetic energy.

Explanation:

The energy is produced in the mitochondria which are packed in the flagellum of the  a sperm cells.Thus as the sperms move the these flagella flips  back and forth,Energy inform of ATPs are generated from the glucose(chemical energy) during cellular respiration in the mitochondria, this  energy is converted to  Kinetic energy for motility.

Specifically,ATP production for the sperm cells is initiated by  Glycolysis. This is because the environments where it swims to meet the ovum punctuates with in oxygen, besides,Glycolysis can occur with or without oxygen.

Sperm motility is very important to male fertility.

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.