Huntington’s disease (HD) is prevalent South Africa. Most of the families with HD have Dutch or British ancestry, which suggests they inherited the European HD allele. HD is believed to have first arrived in South Africa more than 300 years ago when Dutch colonists settled into the Western Cape in the 1600s. Thus, the prevalence of HD in South Africa is the result of the founder effect. Mutations in the HTT gene cause Huntington’s disease. The HTT gene provides instructions for making a protein called huntintin. This protein plays a role in nerve cells in the brain. The HTT mutation that causes HD involves a DNA segment known as a CAG trinucleotide repeat. This segment is made up of a series of three DNA building blocks that appear multiple times in a row. Normally, the CAG segment is repeated 10 to 35 times within the gene. In people with HD, the CAG segment is repeated 36 to more than 120 times. An increase in the size of the CAG segment leads to the production of an abnormally long version of the huntintin protein. This causes the dysfunction and eventual death of neurons in certain areas of the brain. The more repeats, the more serious the disease is.

HD is inherited in an autosomal dominant pattern. There is both an adult onset (after reproductive age) and a juvenile onset pattern. People with adult onset typically have 40 to 50 repeats, while people with the juvenile form tend to have more than 60 repeats. Individuals who have 27 to 35 repeats do not develop HD, but they are at risk of having children who will develop the disorder. As the gene is passed on to offspring, the size of the repeat may lengthen into the range associated with HD.

Predict what will happen to the allele frequencies for Huntington’s disease in South Africa if there were a new mutation to the HTT gene that causes a reduction to the CAG trinucleotide repeat. Justify your prediction with evidence. Your response should include links to the sources of information gathered.

the way that the mass of carbon can be conserved through cellular respiration is through a process/law called the law of conservation of mass which even tho it undergoes a process, mass is not be destroyed or changed

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave

question#1

ans:

cell is the basic unit of organization of all living things. cells are often called the building block of life and it is the smallest unit of life. the study of cell is called cell biology. cell consists of cytoplasm enclosed within membrane, which contain bio-molecules such as proteins and nucleic acid.

two third of cell is water, which means that two-third of your whole body is water. the rest is the mixture of molecules, mainly proteins, lipids and carbohydrates.

question#2

ans:

organ:

an organ is a group of tissues specialized to form a functional unit. an example is the heart in animals.

organ system:

an organ system is a group of several organs whose functions are synchronized to release an effective action in a living organism. an example is digestive system.

question#3

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#4

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system—working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#5

our body works because of the interactions that happen between organs and organ systems.  

for example:  

the heart to regulate blood flow throughout the body. the blood carries oxygen and nutrients to the cells and carries carbon dioxide and waste away from the cells. body systems work together in maintaining a constant internal environment. when this balance is disrupted, the body systems may not function properly, and human health can suffer.   you start to feel bad.

they kick it to the curb.

explanation:

that current was nasty.