1. DNA
Deoxyribonucleic Acid

2. Composition
A nucleic acid made up of monomers nucleotides

3. Recall: Nucleotides are made of
A phosphate group
A nitrogenous base
A 5-carbon sugar  deoxyribose

4. 4 Different Nitrogenous bases Make Up DNA
Adenine  A
Cytosine  C
Guanine  G
Thymine  T

5. Forming the Double Helix
Composed of sugar-phosphate strands ( two of them)
Strands are held together by hydrogen bonds

7. Base-Pairing
hydrogen bonds could create a nearly perfect fit between nitrogenous bases along the center of the molecule.
This fit between A–T and G–C nucleotides is known as base pairing.

8. DNA Replication Process through which DNA is copied or duplicated
This happens during the Synthesis Phase (S phase) of the cell cycle

9. Occurs to copy the genetic information from one cell to another
Enzymes separate the two strands from the double helix and then “synthesize” two new strands in order to get two complete copies of the double helix.

10. Because each strand can be used to make the other strand, the strands are said to be complementary.

11. DNA replication results in two DNA molecules each with one new strand and one original strand

12. The role of enzymes
DNA polymerase is an enzyme that joins individual nucleotides to produce a new strand of DNA.
DNA polymerase also “proofreads” each new DNA strand, ensuring that each molecule is a perfect copy of the original.

13. RNA

14. RNA
Ribonucleic acid
Principle molecule that carries out the instructions coded in DNA

15. RNA vs. DNA 1. RNA contains ribose instead of deoxyribose like DNA.
2.RNA contains uracil instead of thymine
3. RNA is a single strand instead of double-stranded. RNA is complementary to one DNA strand.

16. The three main types of RNA are messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA).

17. Transcription During transcription, segments of DNA serve as
templates to produce complementary mRNA molecules.
The base sequences of the transcribed RNA complement
the base sequences of the template DNA.

18. RNA Polymerase .
RNA polymerase binds to DNA during transcription and separates the DNA strands.
RNA polymerase then uses one strand of DNA as a template from which to assemble nucleotides into a complementary strand of mRNA.

19. Genetic Code
The sequence of amino acids that give a person his or her genetic information.

20. The specific amino acids in a polypeptide, and the order in which they are joined, determine the properties of different proteins.
The sequence of amino acids influences the shape of the protein, which in turn determines its function.

21. Each three-letter “word” in mRNA is known as a codon.
A codon consists of three consecutive bases that specify a single amino acid to be added to the polypeptide chain.

22. Ribosomes use the sequence of codons in mRNA to assemble amino acids into polypeptide chains.
The decoding of an mRNA message into a protein is a process known as translation.

23. Translation begins when a ribosome attaches to mRNA
the ribosome reads each codon of mRNA, and directs tRNA to bring the specified amino acid to the ribosome.
the ribosome attaches each amino acid to the growing chain.

24. What is the “central dogma” of molecular biology?
The central dogma of molecular biology is that information is transferred from DNA to RNA to protein.

25. One of the most interesting discoveries of molecular biology is the near-universal nature of the genetic code.
Despite their enormous diversity in form and function, living organisms display remarkable unity at life’s most basic level, the molecular biology of the gene.

26. Mutations

27. Types of Mutations 1. Gene Mutations 2. Chromosomal Mutations
produce changes in a single gene
2. Chromosomal Mutations
produce changes in whole chromosomes

28. Gene Mutations
Mutations that involve changes in one or a few nucleotides are known as point mutations because they occur at a single point in the DNA sequence. They generally occur during replication.

29. Point Mutations
Point mutations include substitutions, insertions, deletions, silent, missense and nonsense mutations.

30. Substitutions
In a substitution, one base is changed to a different base.
Substitutions usually affect no more than a single amino acid- missense, and sometimes they have no effect at all-silent.

31. Insertions and deletions are called frameshift mutations because they shift the “reading frame” of the genetic message. Frameshift mutations can change every amino acid that follows the point of the mutation and can alter a protein so much that it is unable to perform its normal functions.

33. Silent Mutations
A mutation that does not change the resulting protein.
Does not change the amino acid sequence

34. Missense Mutation Change one amino acid in the resulting protein
The “meaning” of one codon changes

35. Nonsense Mutation
A stop codon is inserted and shortens the resulting protein

36. Types of Chromosomal Mutations
Deletion
Duplication
Inversion
Translocation

37. Deletion
Deletion involves the loss of all or part of a chromosome.

38. Duplication
Duplication produces an extra copy of all or part of a chromosome.

39. Inversion
Inversion reverses the direction of parts of a chromosome.

40. Translocation
Translocation occurs when part of one chromosome breaks off and attaches to another.

41. Effects of Mutations How do mutations affect genes?
The effects of mutations on genes vary widely. Some have little or no effect; and some produce beneficial variations. Some negatively disrupt gene function.