Aaaannnddd I'mmm baccckkk!!!!

Hello all!

A hearty New year to you all!
I realise I'm a little behind the times with this post, mainly because I spent my Christmas holidays revising for mock exams, the first of which I had at 9am on the first day back - how cruel is that?!

How I looked

How I felt

Anyway, I had my final mock yesterday and I thought it was a breeze, although that probably means I completely fluffed up!
So I thought I'd try and squeeze a post in between my psychology homework and my biology homework.
On the subject of school, I'm really enjoying my lessons this year, much more so than in year 12 at AS, I'm finding biology much easier, although I'm glad we finally finished Unit 4 last week - no more photosynthesis! I'm telling you, I've studied photosynthesis every year since year 4 - I'm extremely bored of it! Anyway, Unit 5 of AQA Biology is really cool - there's DNA technology and genes and the nervous system, and all the cool human stuff, much better than plants IMO!

As for psychology, there were four options for OCR, of which two must be studied: Forensic, Health, Education, Sport.
My school does Forensic (as we offer law at GCSE) and Sport (because we're a sports and technology thingy - apparently). Personally I'd prefer education over Sport, but we don't start that section until next week so I'm not going to make my mind up yet! The other unit comprises of approaches and perspectives and evaluation, but we also have a section in the exam where we have to plan our own practical study based on the criteria we're given - I really enjoy this bit, hence why I liked yesterday's exam!

And finally, OCR B History (I dropped geography - I don't like the human side and that was all A2 consisted of). This year we study British imperialism with one teacher, 3 lessons a week, and have a controlled assessment in May (a really nice exam as long as you are properly prepared!) and with the other teacher we are doing coursework 1 lesson a week - "personal study" on the significance of a topic of our own choosing. I was originally going to do Pioneering Palaeontologists, but my research told me that would be extremely difficult in the time-frame, so I chose something I am even more passionate about - Scouts. My question is: "How significant was the birth of Scouting?" I've completed my first full-draft and am now changing bits as necessary, although I am over the 3000 word limit so I need to do some cutting down. There are 6 other students in my class and their topics are: The Aztecs, Leni Riefenstahl, The French Renaissance, Something to do with Poland, and Karl Marx.

I am also doing an EPQ (Extended project qualification) for AQA, as you will know if you have read my blog before. I was originally going to do it on settlement structures and build models, but I was advised against this and have instead decided to ask "Have human needs changed, and how has this affected our lifestyle?"
I'm actually quite enjoying this, but I am panicking about getting it completed to an A grade standard, I know that I'm well ahead of my classmates as we have just been told to begin writing and to have 3000 words by the 29th January - I'm curently on 2,700 while most haven't yet begun, however, I have a tendency to write what's in my head and am then unable to work out what order I should place it in. I follow the principle of "Don't get it right, get it writ", however, I often lose motivation to then get it "right" after its been "writ". I am getting better though and I'm going to spend Saturday on my EPQ and Sunday on the bits of homework that I should be doing as I write this post.

I think that'll do for school, I spend enough time with school work as it is, without writing about it endlessly!
I'll tell you what I'm looking forward to in 2014, perhaps that will help motivate me to finish this homework...

1. Turning 18 and going to the Warner Bros studio tour with my best friend - I will buy EVERYTHING!
2.Getting my EPQ done and dusted by March 26th - more free time!
3.Having my History coursework done by Easter - more revision time!
4.Having my history exam done by the second week of May - Only two subjects left!
6. Super long summer holiday!
5. Spending a long weekend with my oldest friend camping while everyone else is at prom - my logic was this - £35 for one night I won't enjoy with a bunch of people I don't like and also have to get a dress Vs £19 for 3 days with my oldest friend doing something we both love, camping by a beautiful lake before I leave for Uni......It was a pretty easy decision really. This is also instead of spending a fortune going to Marbella or somewhere with my friends who will spend the whole week in the hotel pool. I like adventure.

6.Results day - This may seem weird because it could make or break my future, but my thinking is, my fate is decided on the day of my last exam, that means I can't change my results and the atmosphere on results day is pretty electric!
7. Moving to Uni - hopefully! I'm really looking forward to packing, is that weird?

I finally watched Toy story this Christmas and it made me want to take all my toys with me to Uni! Of course, anyone that has ever seen my room will understand that that will be impossible, so I don't doubt there will be many moments like this:

I told you earlier I spent the whole of the holidays revising - that wasn't strictly true - for the days before Christmas, up until Christmas eve, I was doing homework and sorting out my stuff in the attic - having a proper clear out, I'm not yet finished though so I'm continuing with that on Sunday if I get all my work done.
I also tried my hand at some new Jewellery, and I'm really happy with how it all turned out!
I'm so proud of the snowman earrings, but they took aaaages to make, I had to have a massage after each completion because I was in agony!

Aren't these snowman earrings adorable! I made a pair for myself to wear on Xmas day! £4 a pair 

My new rubber band bracelets - £3 for top two, £2 for third one, £1 for bottom.

£1 each

How did I forget this - who saw the new series of Sherlock?! I loved it! The second episode had me in stitches, and the final one was brilliant! I do think Benedict Cumberbatch is excellent in the role, and the way he can pretend to show emotion and then immediately be nonchalant is brilliant! I'm halfway through reading Arthur Conan Doyle's Hound of The Baskervilles and I'm really enjoying it! I even managed to quote it in my History mock (something about free trade), which was pretty cool.

Anyhoo, I think that's a pretty good round-up of everything since my last post, and I should probably get on with this biology homework - I seem to have "inherited" procrastination from my Dad. See what I did there? eh?!

Alons-Y!

Biology Unit 1 - Topic 1 - Causes of disease

BIOLOGY UNIT 1

1.Causes of Disease

1.1_Pathogens

• Pathogens are microorganisms.

WHAT IS DISEASE?

• Disease is a description of certain symptoms, not a single ‘thing’.
• Could be physical, mental, or both.
• Disease suggests malfunction in the body or mind resulting in adverse effect on health.

MICROORGANISMS AS PATHOGENS

 To be a pathogen, a microoganism must:

• Gain entry to host
• Colonise tissues of host
• Resist defences of host
• Cause damage to host tissues

• Pathogens include bacteria, viruses and fungi.
• If a pathogen colonises a hosts tissues, infection is the result.
• Disease occurs when infection leads to recognisable symptoms in host.
• When a pathogen is transferred from one individual to another, this is called transmission.

HOW DO MICROORGANISMS GET INTO THE BODY?

·        Pathogens get into the body by penetrating one of the organisms interfaces with environment.

·        One interface is the skin when it is broken. (When unbroken the skin is a thick, continuous layer so is an effective barrier to infection.)

·        Some interfaces have evolved to allow exchange of material so linings here are thin, moist, have a large surface area and are well supplied with blood vessels. This makes for easy entry for molecules, including pathogens.

·        Examples include the gas exchange system – Many pathogens enter here, including ones that cause influenza, TB and bronchitis.

Digestive system – Food and water can carry pathogens into stomach and intestines via mouth, pathogens such as cholera, typhoid and dysentery enter here.

·        To try and prevent entry, body has natural defences:

-Mucus layer covers exchange surfaces and forms thick sticky barrier that’s difficult to penetrate.

-Enzymes break down pathogens.

-Stomach acid kills microorganisms.

HOW DO PATHOGENS CAUSE DISEASE?

Two main ways:

·        Damaging host tissues – sometimes just the number of them by preventing tissues functioning properly. Viruses inhibit synthesis of DNA, RNA and proteins. Many pathogens break down membranes of host cells.

·        Producing toxins – Most bacterial pathogens. Cholera bacterium produces toxin that leads to excessive water loss from lining of intestines.

·        Some diseases like malaria have just one cause, while others like heart disease have a number of causes.

·        How quickly a pathogen causes damage is related to how quickly it divides.

·        Pathogens like those causing gastroenteritis, deivide every 30mins so symptoms become apparent within 24 hours. Gastroenteritis pathogen only causes damage in large numbers.

·        Pathogens such as typhoid bacterium cause harm in small numbers.

1.2_Data and Disease

ANALYSING AND INTERPRETING DATA ON DISEASE

• Epidemiology is the study of the incidence and pattern of disease with a view to finding means of preventing and controlling it.
• Epidemiologists collect data and look for a pattern or relationship between the diseases and various factors in lives of people who have them.

CORRELATIONS AND CAUSAL RELATIONSHIPS

CORRELATIONS DO NOT MEAN CAUSATIONS!!!!!

• A correlation occurs when a change in one variable is reflected by a change in the other.
• This does not however mean that we can say that one change CAUSES the other.

1.3_Lifestyle and health

WHAT IS RISK?

A MEASURE OF THE PROBABILITY THAT DAMAGE TO HEALTH WILL OCCUR AS A RESULT OF A GIVEN HAZARD.

Concept of risk has 2 elements:

-Probability that hazardous event will occur.

-Consequences of that hazardous event.

• These factors affect how we perceive risk, e.g. risk of catching a cold is high, but consequences are minor so we don’t tend to worry much.
• Consequences of being struck by lightening are severe, but unlikely to happen so again, we don’t worry too much.
• When both factors are high = worry.

Risk is measured in %.

Health risks need timescale – telling someone risk of dying is 100% is meaningless, saying their risk of dying in the next month is 100%, has a totally different meaning.

Risk is often relative – Risk is measured by comparing likelihood of harm occurring in those exposed to a hazard with those not exposed to it. i.e. Smokers are 15x more likely to develop lung cancer.

Misleading statistics – reports in media may be misleading as they focus on a single figure, suggesting this figure applies to everyone.

LIFESTYLE CHOICES AND CANCER

Can’t do anything about our genes, or age, but lifestyle can expose us to environmental and carcinogenic factors.

*Smoking – nicotine is a carcinogen, and can affect passive smokers too.

*Diet – What we eat & drink affects risk of contracting cancer.

*Obesity – Being overweight increases risk.

*Physical activity – People who take regular excersise have lower risk from some cancers than those who do not exercise.

*Sunlight – Great exposure to UV rays increase risk of developing skin cancer.

RISK FACTORS AND CORONARY HEART DISEASE

·        CHD is largest cause of death in UK.

·        When combined, 4/5 of the risk factors produce a disproportionately greater risk.

LIFESTYLE CHOICES AND CHD

Can’t control genes age or sex.

But can control:

·        Smoking – Smokers between 2 and 6 times more likely to suffer from CHD.

·        High Blood Pressure – Excessive prolonged stress, certain diets and lack of exercise increase blood pressure and hence risk of CHD.

·        Blood cholesterol levels – Can be kept lower by includning fewer saturated fats and fatty acids in diet.

·        Obesity - BMI of over 25 = increased risk.

·        Diet – High levels of salt raise blood pressure while high levels of saturated fatty acids increase blood cholesterol concentration.

·        Physical exercise – Aerobic exercise can lower blood pressure and blood cholesterol as well as helping to avoid obesity.

Infection- invasion and multiplication of microorganisms in body tissues

Disease-  A disorder of structure or function in a human, animal, or plant, that produces specific signs or symptoms

Transmission- The transfer of a pathogen from one individual to another.

Interface- A point where two systems, subjects, organizations, etc., meet and interact.

RNA- ribonucleic acid; any of a group of nucleic acids, present in all living cells, that play an essential role in the synthesis of proteins.

Topic 8.1

Structure of DNA

Nucleotide structure

Individual nucleotides of DNA are made up of:

• Sugar – Deoxyribose
• Phosphate group
• Organic base

Single-ring bases – Cytosine (C) and Thymine (T)

          OR

Double-ring bases – Adenine (A) and Guanine (G)

T=A

C=G

=Hydrogen bonds

 

                             

*These three components are combined as a result of condensation reactions to give a mononucleotide.

-Two mononucleotides may combine as a result of a condensation reaction between the deoxyribose sugar of one mononucleotide and the phosphate group of another. This new structure is a dinucleotide.

-A long chain of mononucleotides is a polynucleotide.

-It is not just DNA that contains nucleotides.

DNA structure

-In 1953, James Watson and Francis Crick worked out the structure of DNA following Rosalind Franklin’s work on X-ray diffraction patterns of DNA.

-DNA is made up of two strands of nucleotides (polynucleotides).

-Each starnd is extremely long and joined together by hydrogen bonds formed between certain bases.

-Simply: Ladder – phosphate and deoxyribose molecules alternate to form the uprights and organic bases pair together to form the rungs.

 

The double helix

-The ladder-like arrangement of the two polynucleotide chains is twisted.

-The uprights of phosphate and deoxyribose wind around each other to form a double helix.

-They form the structural backbone of the DNA molecule.

-For each complete turn of the helix, there are ten base pairs.

Function of DNA

-DNA is the hereditary material responsible for passing genetic information from cell to cell and generation to generation.

-There are around 3.2 billion base pairs in DNA of a typical mammalian cell.

  This means there is an almost infinite variety of sequences of bases on the length of a DNA molecule, providing immense variety in living organisms.

How DNA molecule is adapted to its functions:

• Very stable and can pass between generations without change.
• Two separate strands, joined with only hydrogen bonds, allowing the to separate during DNA replication and protein synthesis.
• Extremely large molecule, therefore carries an immense amount of genetic information.
• Having base pairs within the helical cylinder of deoxyribose-phosphate backbone, genetic information is protected from being corrupted by outside chemical and physical forces.
• The function of DNA depends on the sequence of the base pairs it posseses.