2.6 Syllabus
U1. The nucleic acids DNA and RNA are polymers of nucleotides.
-Helocase enzyme → Need energy to break the H bonds
-Job of DNA polymerase: To add free nucleotide
-When it pairs: complementary base pair takes place
-Two types: 1. DNA 2. RNA
-Very large molecules that are constructed by linking together nucleotides to form a polymer
- Consists of three parts:
1. Sugar: Five carbon atoms (ribose sugar) = pentose sugar
2. Phosphate: Acidic, negatively-charged part of nucleic acids – DNA/ RNA, nucleic tide (single structure)
3. Base: contains nitrogen and either one or two rings of atoms in its structure
-Base and phosphate linked by covalent bonds
-To link nucleotides together into chain or polymer, covalent bonds are formed between phosphate of one nucleotide and pentose sugar of next nucleotide
→Creates a strong backbone for molecule of alternating sugar and phosphate groups, with base linked to each sugar.
-There r four different bases in DNA and RNA which means four nucleotides.
→ four different nucleotides can be linked together in any sequence since phosphate and sugar used to link them are the same in every nucleotide.
-Nuclei acids acting as a store of genetic information
-Base Sequence: store of information
-Sugar phosphate backbone: ensures that the store is stable and secure
-Job of DNA polymerase: To add free nucleotide
-When it pairs: complementary base pair takes place
- Nucleic acids
-Two types: 1. DNA 2. RNA
-Very large molecules that are constructed by linking together nucleotides to form a polymer
- Consists of three parts:
1. Sugar: Five carbon atoms (ribose sugar) = pentose sugar
2. Phosphate: Acidic, negatively-charged part of nucleic acids – DNA/ RNA, nucleic tide (single structure)
3. Base: contains nitrogen and either one or two rings of atoms in its structure
-Base and phosphate linked by covalent bonds
-To link nucleotides together into chain or polymer, covalent bonds are formed between phosphate of one nucleotide and pentose sugar of next nucleotide
→Creates a strong backbone for molecule of alternating sugar and phosphate groups, with base linked to each sugar.
-There r four different bases in DNA and RNA which means four nucleotides.
→ four different nucleotides can be linked together in any sequence since phosphate and sugar used to link them are the same in every nucleotide.
-Nuclei acids acting as a store of genetic information
-Base Sequence: store of information
-Sugar phosphate backbone: ensures that the store is stable and secure
U2. DNA differs from RNA in the number of strands normally present, the base composition and the type of pentose
1. Sugar within DNA: Deoxyribose (One fewer oxygen)Sugar in RNA: Ribose
2. DNA: Two polymers/strands of nucleotides=Double strandedRNA: ONE = single stranded
3. Four bases in DNA= Adenine, Cytosine, Guanine, Thymine
Four bases in RNA= Adenine, Cytosine, Guanine, Uracil
2. DNA: Two polymers/strands of nucleotides=Double strandedRNA: ONE = single stranded
3. Four bases in DNA= Adenine, Cytosine, Guanine, Thymine
Four bases in RNA= Adenine, Cytosine, Guanine, Uracil
U3. DNA is a double helix made of 2 antiparallel strands of nucleotides linked by hydrogen bonding between complementary base pairs
- Each strand consists of chain of nucleotides linked by covalent bonds
- Two strands are parallel but run in opposite directions so it is antiparallel. One stand oriented in direction 5-3 and other is 3-5
- 2 strands are wound together to form a double helix
- Strands are held together by H bonds between the Nitrogenous bases. A-T/ G-C =Complementary base pairing