Humans are Dioecious i.e. contain male and female gonads in different individuals. Male Gonads produce sperms and the female gametes produce Ovum. Lower animals ad plants are usually Monoecious.
The chromosomes which help in determination of the sex of the offspring are called the Allosomes or Sex Chromosomes. Whereas the vegtative chromosomes which are not helpful in sex are called the Autosomes.
The method of sex determination in Human Beings is XY type, where in males, the Allosomes are XY type and in females the allosomes are XX
type. Humans contain 46 chromosomes in the nucleus of the cell out of which, 44 are autosomes and other 2 are allosomes.
On production of gametes, the no. of chromosomes is reduced to half , i.e. in the gametes there are 23 chromosomes. But the type of chromosomes is not same.
In females, ova contains 22 autosomes and 1 X chromosome.
In males, the sperm contains 22 autosomes as in ovum but the allosome can be either X or Y type, i.e. a sperm can contain either X or Y allosome.
During fertilisation, if sperm with X allosome fuses with the ovum, then it results into formation of female offspring (XX) and if Y allosome of male fuses with the ovum, then it results to the formation of Male offspring (XY).
Thus, Ovum has no role in sex determination but the sperm has the role of sex determination in human beings, i.e. if sperm has X allosome, offspring is female and if Y allosome is present, offspring if male
Sabtu, 05 Juni 2010
Obesity In America and it’s relations
Obesity is the number one disease in America. Day by Day more people are looking into getting physically fit. There are two types of fitness, one is health related and the other is performance. The health aspect of fitness is related to doing exercises in getting your blood pressure lowered, prevent heart attacks and so forth. The performance side is for athletic type people and that tests for agility, balance and body power. Overall being healthy gives you more energy to do the things you couldn’t do before and it also makes you feel better about yourself mentally.
The benefits of exercise is to make you feel and look better, to have more energy and improve your health in general. A misconception is that if you are overweight you cannot be fit but that is not true. You can be physically fit and still be over what you should weigh. Exercising can lower your chance of heart attack , burn calories so that you can lose weight. Doctors have done studies that show that you can think quicker and clearer if you are more fit. Studies have also
shown that people are less likely to be depressed or have anxiety.
Before you begin and type of exercise program check with your doctor to make sure that it is ok. There are many forms of exercise that you can depending on your fitness level and interests. You should pick an activity that you will enjoy so that you won’t get bored.
There is sports who those people that like to play tennis, basketball or racket ball. For others there is aerobics, Pilates, weight lifting and bicycle riding. Then there are people who like to go to the gym and use the Stair climber, Treadmill and Stationary Bicycles. Some people only do types of exercise that don’t really feel like exercise such as dancing or walking.
No matter what type of exercise that you do make sure you execute properly so that avoid injury. Overall, have fun!
The benefits of exercise is to make you feel and look better, to have more energy and improve your health in general. A misconception is that if you are overweight you cannot be fit but that is not true. You can be physically fit and still be over what you should weigh. Exercising can lower your chance of heart attack , burn calories so that you can lose weight. Doctors have done studies that show that you can think quicker and clearer if you are more fit. Studies have also
shown that people are less likely to be depressed or have anxiety.
Before you begin and type of exercise program check with your doctor to make sure that it is ok. There are many forms of exercise that you can depending on your fitness level and interests. You should pick an activity that you will enjoy so that you won’t get bored.
There is sports who those people that like to play tennis, basketball or racket ball. For others there is aerobics, Pilates, weight lifting and bicycle riding. Then there are people who like to go to the gym and use the Stair climber, Treadmill and Stationary Bicycles. Some people only do types of exercise that don’t really feel like exercise such as dancing or walking.
No matter what type of exercise that you do make sure you execute properly so that avoid injury. Overall, have fun!
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