Year 13 update

Hello all,

You may remember that towards the end of August I was preparing for heading back to school after the summer holidays, to begin by final year of school, I thought i'd update you on how the last week has gone.

School began on wednesday 4th September for years 7,12 and 13, with the rest of the school coming back on the Thursday.
This was  to give the newbies a chance to settle into high school and sixth form, Year 13 had to go in as we were running the induction day with the year 12s and we are encouraged to make friends cross both year groups, rather than only in our own.

The induction day consisted of making balloon chairs, spiders web and other team building activities.

My teams balloon chair

After the activities we had an assembly and got to go home at 3pm.

In the 5 days since however, I have had lessons each day, although I do have many more frees now as I have dropped geography this year, so I will only be doing Biology, Psychology and History this year.

On top of the extra study time, my dad is currently planning my own little study so that I can utilise my study time at home more effectivley as my room at the moment is too small for me to be organised.

When it is finally completed, I will upload some before and after pictures.

For now however, it is getting late and I have some bracelet commisions to complete before the day is out so I should get a shower and do them before I settle down in front of the TV. 

I will be posting an in-depth daily routine one of these days to show you how I organise my school work, as well as having that all important "me time", and maybe it will help one of you guys!

Alons-y!

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.