Thread of Life Revision: OCR B salters

A revision booklet addressing all the points in the specification in sufficient detail. Some diagrams and mechanisms/structures may need to be drawn out, All of which can be found in revision guides, the OCR chemical ideas text book, exam datasheets or the chemical storylines textbook!

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How To Use this Booklet:

This booklet has been created by addressing all the points on the OCR B
salters specification for the section, what's in medicine. I advise reading
through the Book, highlighting or underlining words written in ALL
CAPITALS. I also suggest making a spider diagram or mind…

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(ii) Use empirical rate equations of the from: rate = K[A]m [B]n where m
and n are integers. Carry out calculations based on the rate equation and
understand that the rate constant K increases with increasing


B) Describe the Characteristics of of…

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Enzyme Kinetics:

Step1: E + S ES (intermediate)

Step 2: ES E + P

At LOW substrate concentrations, step ONE is the rate-determining step. Thus
the reaction is FIRST ORDER with respect to both enzyme and substrate.
However, enzymes are molecules with a large Mr so their molar concentrations

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Amino acids are BIFUNCTIONAL molecules- they contain both the amino (-NH2)
and carboxyl (-COOH) functional groups. When these functional groups are
attached to the same carbon atom, the amino acid is called an ALPHA ( )

For all amino acids (EXCEPT GLYCINE for which R=H), -amino acids have…

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When several amino acids are joined together in this way, a POLYPEPTIDE is
formed. PROTEINS are naturally occurring condensation polymers formed
when many amino acids join together!


When a peptide link or protein s REFLUXED with MODERATELY
CONCENTRATED ACID OR ALKALI for several hours, the C-N bond in the…

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Sensitive to pH: pH affects the ratio of ­COO- to NH+ present in R groups. Small
changes of pH can affect the charges of the R groups present in the active site
itself, resulting in a decrease in activity. A change of pH of more than 2 units
causes the…

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(ii) Explain, using the structures in the Date Sheets, how phosphate units
join with deoxyribose to form the phosphate-sugar backbone in DNA.
The four bases present in DNA join by condensation with the
deoxyribose in the phosphate-sugar backbone. Two strands of DNA form
a double-helix structure through base pairing


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(L)Using the structures on the Data Sheets, describe and explain the
significance of hydrogen bonding in the pairing of bases in DNA, and
relate to the replication of genetic information; use the diagram on the
data sheet to explain how DNA encodes for an amino acid sequence in a

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(M) Understand that DNA analysis can be used for `genetic
fingerprinting'; discuss the ethical issues of using and storing data from
human DNA analysis.

DNA DATABASES Since DNA is different in every individual (except identical
twins), DNA sequences can be used to identify individuals.…


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