B2 Flashcards
What is the information in the cells?
Each of your cells has a nucleus that contains chromosomes.
Chromosomes carry the genes that contain the instructions for making both new cells and all the tissues and organs needed to make an entire new you.
A gene is a small package of information that controls a characteristic, or part of a characteristic, of your body. It is a section of DNA, the unique molecule that makes up your chromosomes.
You have 46 chromosomes in the nucleus of your body cells. They are arranged in 23 pairs. In each pair of chromosomes, one chromosome is inherited from the father and one from the mother. As such, sex cells (gametes) only have one chromosome from each pair, but only have 23 chromosomes in total.
What are the stages of the cell cycle?
Stage 1: This is the longest stage in the cell cycle. The cells grow bigger, increase their mass, and carry out normal so activities. Most importantly they replicate their DNA to form two copies of each chromosome ready for cell division.
Stage 2-Mitosis: in this process one set of chromosomes is poured to one side of the dividing cell and the nucleus divides.
Stage 3: This is the stage during which the cytoplasm and the cell membranes also divide to form two identical daughter cells.
What is differentiate?
The cells of your body, or any complex multi cellular organism, or not all the same. They are not the same as the original shell either. This is because, as cells divide, grow and develop, they also begin to differentiate.
What happens to animal cells to become adults stem cells?
Most specialised cells can divide by mitosis, but they can only form the same sort of cell. Muscle cells divide to produce more muscle cells, for example. Some differentiated cells, such as red blood cells and skin cells, cannot divide at all and so adult stem cells replaced dead or damaged cells. Nerve cells do not divide once they have differentiated and they are not replaced by stem cells. As a result, when nerve cells are damaged they are not usually replaced
Cloning plants?
Producing identical offspring is known as cleaning. Huge numbers of identical plant clones can be produced from the tiny piece of leaf tissue. This is because, in the right conditions, a plant so will become on specialised in undergo mitosis many times. Each of these undifferentiated cells will produce more cells by mitosis. Given different conditions, these will then differentiate to form tissues such as xylem, phloem,photosynthetic cells, and rehearsals that I needed to form a tiny new plant. The new plants will be identical to the original parent.
What is the function of stem cells?
And egg and sperm cell fuse to form zygote, a single new cell. That’s cell divides and becomes a hollow ball of cells-the embryo. The inner shells of the sport are the embryonic stem Cells that differentiate to form all of the specialised cells of your body. Even when you are an adult, some of the your stem cells remain. An adult stem cell is an undifferentiated cell of an organism that can give rise to many more cells of the same type. Certain other types of cell can also arise from stem cells by differentiation. Your bone marrow is a good source of adult stem cells. Scientists now think there may be a tiny number of stem cells in most of the different tissues in your body including your blood, brain, muscle, and liver.
What is the use of stem cells?
Many people suffer and even die because parts of their body stop working properly. For example, spinal injuries can cause paralysis, because the spinal nerve cannot repair themselves. People with type 1 diabetes have to inject themselves and insulin every day because specialise cells in the pancreas do not work. Millions of people would benefit if we could replace damaged or diseased body parts.
Stem cells in plants?
The stem cells from plant meristems can be used to make clones of the mature parent plant very quickly and economically. This is important as it gives us a way of producing large number of rare plants reliably and safely. We may be able to save some rare plants from extinction in this way. Plant cloning also gives us a way of producing large populations of identical plants for research. This is important as scientists can change variables and observe the effects on genetically identical individuals.
What is the problem with embryonic stem cells?
Many embryonic stem cells come from aborted embryos. Others come from spare embryos from fertility treatment, donated because they will not be used. Some people question the use of a potential human being as a source of source, even to cure others. Some people feel that, as the embryo cannot give permission, using it as a violation of human rights. The religious beliefs of others mean they cannot accept any interference with the process of human reproduction.
Embryonic stem cells divide and grow rapidly. This is partly why there are potentially so useful but there is some concern that embryonic stem cells might cause cancer if they are used to treat people.
Some people feel that a great deal of money and time has been wasted on stem cell research that will be better spent on research into other areas of medicine. Yet in spite of all these concerns, there is a lot of investment into stem cell research as many scientists and doctors are convinced stem cells have the potential to benefit many people.
What is the future of stem cell research?
Scientists have found embryonic stem cells in the umbilical cord blood of newborn babies and even in the amniotic fluid that surrounds the fetus as it grows. Using these instead of cells from spare embryos may help to overcome some of the ethical concerns about their use.
Scientists are also finding ways of growing adult stem cells, although so far they have only managed to develop them into a limited range of So types. Adult stem cells avoid the controversial use of embryonic tissue. They have been used successfully to treat forms of heart disease and to grow some new organs such as tracheas (windpipes).
At the moment, after years of relatively slow progress, hopes are high again that stem cells will change the future of medicine. Currently, in the UK, stem cell research has been carried out into potential therapist to treat:
Spinal-cord after injuries
Diabetes
Heart after damage in a heart attack
Eyesight in the blind
Damage bone and cartilage.
