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AS and A Level: Genetics, Evolution & Biodiversity
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- Marked by Teachers essays 33
- Peer Reviewed essays 15
An Investigation into the Mitotic Nuclear Division of Allium Sativum Root Tip Cells, and the Relative Duration of Each Phase of this Cellular Cycle5 star(s)
In this investigation, it is believed that the durations of each phase in the process of mitotic nuclear division vary, for the following biological and biochemical reasons. Stage B: Prophase: 20 relative time units Prophase is the cellular cycle stage of mitosis in which chromatin condense into a highly ordered structure called a chromosome (7, 8). Since the genetic material has been duplicated, there are two identical copies of each chromosome in the cell. The other important cellular organelles in the prophase stage are the centrioles (1).
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Mental health is linked to behaviour Mental, social and behavioural health problems could interact and have a large effect on an individual's behaviour and well-being. These following examples could have effects on an individual's behaviour and well being and could cause them to find it very difficult to cope, these are as follows: Substance abuse, violence, and abuses of women and children, health problems such as heart disease, depression, and anxiety. (www.who.int) What is mental illness? A mental illness is a health problem that significantly affects how a person feels, thinks, behaves, and interacts with other people.
- Word count: 11946
Samples will be used to identify which brackens have a tall height in relation to its area or variables, which area listed below. The statistical test that I will use to interpret these data is the 'Mann-Whitney U' test. This is used to calculate the medians of the two sets of data collected (one from the light and one from the dark area) and would show if the difference in height between the areas is significant or not. This will be used to measure the strength of the relationship between two variables.
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Evaluation of Sources Nature vs. nurture has been an oscillating controversy in the field of psychology for many years. Does one inherit genes, or are one's genes affected by the environment? This question has been the focal point in the field of psychology for decades. As more and more case studies are coming out with results, a clearer picture comes into view. The "picture" portrays how the blend of both nature and nurture affects human growth and development. The basis of nature is the principle that people have their personalities engraved inside their genes, which are inherited by their parents.
- Word count: 3331
An estimation of forty Siberian tigers in the wild in 1940 led the former Soviet Union to place the Siberian Tiger on the endangered species list. Poaching became a problem again in 1990 when the economy of Russia collapsed3. Poaching in Siberian tigers has led to: * Population of Siberian tigers decreasing, * Demand of Siberian tiger pelage high (causing poaching to increase)2, * Siberian tigers to lose habitat (their habitat is not safe anymore), * Offspring to become scarce (cubs will not be able to survive without parent); * Low survival rate in wild caused by Siberian tigers to become domesticated when forced to be used as a pet by local humans.
- Word count: 3025
Caffeine abuse causes palpitations, tremors, diarrhea, nausea, chest pains, sweating, vomiting and neurological symptoms. Addicts develop tolerance for caffeine and require a higher dosage every time to achieve the desired effects (Hasan 24). Early studies showed that high levels of Caffeine made the heart beat abnormally fast and constricted cerebral blood vessels in the human brain. Therefore, if a caffeine addict decided to stop drinking coffee for a day, their blood vessels would dilate resulting in a powerful headache. Other symptoms include fatigue and melancholy when withdrawing from caffeine (Caffeine). Caffeine's sensitivity varies from human to human but high levels of caffeine isn't good for the human body, as it is linked to restlessness, insomnia, anxiety, stress, heart irregularities and an increase in blood pressure.
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Reduced adenosine activity also contributes to increased dopamine activity5, a neurotransmitter which is a precursor in the production of epinephrine6. Together, these effects increase the levels of epinephrine in the brain. ADHD (attention-deficit hyperactivity disorder) is caused by a deficiency in dopamine, and its treatments raise dopamine levels7. This suggests that dopamine also plays a part in attention and concentration. Synapse showing antagonistic action of caffeine on adenosine receptors - http://www.snabonline.com/pupil/mediabank.aspx -> Book artwork with no labels -> Figure 8.57 - 22/10/08 As well as blocking adenosine receptors, caffeine also blocks the removal of cAMP (cyclic adenosine monophospate) from cells.
- Word count: 4449
Cloned animals will be living in factories that would be able to produce a range of human drugs to helps us with various illnesses and maybe even diseases. The purpose of cloning Dolly was to see if the idea of a different way to producing animals, would actually work. Cloning mammals means that you can use larger animal types. Definition of terms What is cloning? Cloning is the production of genetically identical animals or humans using laboratory-grown cells. The term cloning (derived from the Greek word klon, meaning "twig")
- Word count: 4230