i just started a PhD and my supervisor has a really bad language and general behaviour towards me.I am thinking about leaving and go for a msc instead, be cause he makes me feel i dont know anything although i have a honors degree in molecular biology and genetics.What should i do?

Your supervisor is supposed to be supportive and certainly shouldn't swear at you, however, it's very common to feel that you don't know anything - because (relatively) you don't know much about the detailed background to your project when you first start. In my experience, the more you learn, the more you realise the extent of knowledge in your field and feel even more ignorant! Not necessarily a bad thing as long as it doesn't dent your confidence. If you want to work in academia/research, stick with the PhD or you might regret it later.

Unfortunately, the way things work at moment (and have done for too long now) PhD supervisors are really not monitored very much and allowed to conduct their labs and themselves however they wish. It's up to you to make it known to your supervisor if you think he or she is behaving badly/inappropriately and to report it to the appropriate person/s at your university or institution.

Your department should offer some kind of advisor or mentoring system which gives you people whose job it is to 'independently' monitor the progress of your project. If not then approach the postgraduate tutor or head of research degrees in your department. Do not drop out without talking about your problem first.

Change your 'supervisor', he's an arsehole.

writing-up now, and sorry to tell you this but this is the 'norm'. I don't know one person who gets on with their supervisor. Their job is to ensure you get through, if they question everything the Viva will be easier. They are also testing you. If you can't take pressure, is it worth their effort? Do you want this or not? If you want it, prove it. If it was easy it wouldn't be worth doing, would it? Dealing with supervisors 101:Do the optional assertiveness courses on offer and prove you are worth it!

The phd is supposed to be difficult in terms of are you intellectually capable enough not are you able to deal with a b*****d. Getting a phd should not be at the cost of your health (mental or otherwise). It is also in the supervisors interest for their students to get through making life almost impossible. And by my experience the mentoring systems are useless.

Sorry thats meant to be not making life impossible.

I am a mature PhD student and the degree needs modernising. One thing it is supposed to teach is leadership and a leader should be able to overcome problems. However, the system is selecting for cunning, irresponsible, pushy behaviour. For example, if money is presented as a problem one student will buy anyway and succeed sooner. The other may work around the problem and take longer. In the long run the first student gets their PhD from their irresponsible behaviour, NOT leadership. As I come from a very successful business world, I am amazed. A review is urgently required!

I suggest either you change to another PhD quickly or you carry on with this one. If continuing, immediately start designing your thesis and do not be intimidated. Stick to what you believe is right and learn as much as possible.