12. Transcription
• Process of copying DNA to RNA
• Differs from DNA synthesis in that only one
strand of DNA, the template strand, is used to
make mRNA
• Does not need a primer to start
• Can involve multiple RNA polymerases
• Divided into 3 stages
– Initiation
– Elongation
– Termination
23. Methyl metabolism showing some major metabolic
intermediates, cofactors and dietary sources of methyl
groups and an intersection with antioxidant metabolism
through homocysteine, cysteine and glutathione.
28. Betaine
• A betaine in chemistry is any neutral chemical
compound with a positively charged cationic
functional group such as a quaternary ammonium or
phosphonium cation (generally: onium ions) which
bears no hydrogen atom and with a negatively
charged functional group such as a carboxylate
group which may not be adjacent to the cationic
site.
• A betaine thus may be a specific type of zwitterion.
• Historically the term was reserved for
trimethylglycine only.
• It is used as a medicine as well.
29. • The correct pronunciation of the compound reflects its
origin and first isolation from sugar beets, and does not
derive from the Greek letter beta (β).
• However, it is often mispronounced beta-INE or even
BEE-tayn In biological systems, many naturally
occurring betaines serve as organic osmolytes,
substances synthesized or taken up from the
environment by cells for protection against osmotic
stress, drought, high salinity or high temperature.
• Intracellular accumulation of betaines, non-perturbing
to enzyme function, protein structure and membrane
integrity, permits water retention in cells, thus
protecting from the effects of dehydration.
• It is also a methyl donor of increasingly recognized
significance in biology.
39. Amino Acid SLC DNA codons
Isoleucine I ATT, ATC, ATA
Leucine L CTT, CTC, CTA, CTG, TTA, TTG
Valine V GTT, GTC, GTA, GTG
Phenylalanine F TTT, TTC
Methionine M ATG
Cysteine C TGT, TGC
Alanine A GCT, GCC, GCA, GCG
Glycine G GGT, GGC, GGA, GGG
Proline P CCT, CCC, CCA, CCG
Threonine T ACT, ACC, ACA, ACG
Serine S TCT, TCC, TCA, TCG, AGT, AGC
Tyrosine Y TAT, TAC
Tryptophan W TGG
Glutamine Q CAA, CAG
Asparagine N AAT, AAC
Histidine H CAT, CAC
Glutamic acid E GAA, GAG
Aspartic acid D GAT, GAC
Lysine K AAA, AAG
Arginine R CGT, CGC, CGA, CGG, AGA, AGG
86. DNA and Mutations – Lets looks at different mutations
القط الكلب عض
THE DOG BIT THE CAT
87. DNA and Mutations - Substitution
القط الكلب عض
THE DOG BIT THE CAT
أخر حرف محله وحل الجملة هذه ًف الحروف أحد غٌر لو
القط القلب عض
• Substitution - Replace just one letter:
THE DOG BIT THE CAR
88. DNA and Mutations - Deletion
القط الكلب عض
THE DOG BIT THE CAT
ًكاألت تصبح الجملة هذه من الباء وهو واحد حرف حدف عند
القط الكل عض
ًكالتال الجملة تصبح ، أخرى إلى كلمة من حرف تحرٌك أو:-
القطب الكل عض
• Deletion: Delete just one letter (T):
THE DOG BIT HEC AT
89. DNA and Mutations-Insertions
القط الكلب عض
THE DOG BIT THE CAT
• Insertion - Add just one letter (E):
ًكالتال الجملة هذه إلى الراء حرف إضافة عند
القطب الكل عرض
THE DOE GBI TTH ECA T
الخالٌاعلى القدرة لهاإصالح وٌتم بإستمرار البروتٌن قراءة
ًف تحدث ًالت األخطاء تصحٌح معظم ٌتم وبذلك الدنا ًف األخطاء
الدنا
Cells have “proof reading” proteins that
constantly check the DNA and fix errors, so
most are corrected