→ IMPORTANCE OF DNA
Nucleus contains deoxyribonucleic acid (DNA)
- Carrier of genetic info in cells
- Duplicated itself, permitting cell division and continuity of life.
- Genetic code with 46 chromies of human body
- 2500 genes (units of instruction) that ensure continuity of life
→ HISTORY OF DNA
Mendel
- Monk who played w peas (genetics unit)
- Showed generally that parents pass traits to their offspring
Morgan
- Extended Mendel’s work
- SShowed that genes are on chromies
Chargaff’s Rules
⭐︎A = T | C = G
- The amount of adenine always equals amount of thymine in DNA samples
- ^ same for cytosine and guanine
● Applying Chargaff’s rules
→ If a sample of DNA was taken and analyzed to contain 32% thymine, how much
cytosine would be expected to be in the same sample?
T= 32%
A= 32%
→ 32% + 32% = 64%
⭐︎[100-64 = 36 | 36/2 = 18%]
C= 18%
G= 18%
→ DEOXYRIBONUCLEIC ACID (DNA)
Regulates production of cell proteins.
Are made of: phosphates, sugar molecules, 1-4 diff nitrogen bases.
, Structure
- Double helix
- Sugar and phosphate molecules form “backbone” of ladder
- N bases form the rungs
- Connected by hydrogen bonds
- Fits into its complementary base
⭐︎ Adenine / Thymine | Guanine / Cytosine
⭐︎ Purines → adenine / guanine
Pyrimidines → cytosine / thymine
DNA Nucleotide
Unit consisting of: phosphate, sugar (deoxyribose), nitrogen base
→ DNA REPLICATION
[In order for mitosis to occur, DNA is replicated in the S-stage of interphase]
DNA replication is semiconservative
- Separation of the two strands to make two new ones
- Hydrogen bonds break, DNA helix “unzips”
- Each strand acts as a template to build complementary strand
- Errors are repaired → two identical copies of DNA
½ old, ½ new !
→ SEPARATING DNA STRANDS
H-bonds and twisting hold the strands together
DNA Helicase
Unwinds helix by breaking H-bonds between complementary base pairs.
- Point where two strands separate is replication fork
- Enrichment : one template strand runs 5’ → 3’ and the 3’ to 5’
⭐︎Helicase Enzyme unzips DNA
Building Complementary Strands
New strands synthesized by DNA polymerase enzyme.
- Link together free nucleotides (from food you eat)
Nucleus contains deoxyribonucleic acid (DNA)
- Carrier of genetic info in cells
- Duplicated itself, permitting cell division and continuity of life.
- Genetic code with 46 chromies of human body
- 2500 genes (units of instruction) that ensure continuity of life
→ HISTORY OF DNA
Mendel
- Monk who played w peas (genetics unit)
- Showed generally that parents pass traits to their offspring
Morgan
- Extended Mendel’s work
- SShowed that genes are on chromies
Chargaff’s Rules
⭐︎A = T | C = G
- The amount of adenine always equals amount of thymine in DNA samples
- ^ same for cytosine and guanine
● Applying Chargaff’s rules
→ If a sample of DNA was taken and analyzed to contain 32% thymine, how much
cytosine would be expected to be in the same sample?
T= 32%
A= 32%
→ 32% + 32% = 64%
⭐︎[100-64 = 36 | 36/2 = 18%]
C= 18%
G= 18%
→ DEOXYRIBONUCLEIC ACID (DNA)
Regulates production of cell proteins.
Are made of: phosphates, sugar molecules, 1-4 diff nitrogen bases.
, Structure
- Double helix
- Sugar and phosphate molecules form “backbone” of ladder
- N bases form the rungs
- Connected by hydrogen bonds
- Fits into its complementary base
⭐︎ Adenine / Thymine | Guanine / Cytosine
⭐︎ Purines → adenine / guanine
Pyrimidines → cytosine / thymine
DNA Nucleotide
Unit consisting of: phosphate, sugar (deoxyribose), nitrogen base
→ DNA REPLICATION
[In order for mitosis to occur, DNA is replicated in the S-stage of interphase]
DNA replication is semiconservative
- Separation of the two strands to make two new ones
- Hydrogen bonds break, DNA helix “unzips”
- Each strand acts as a template to build complementary strand
- Errors are repaired → two identical copies of DNA
½ old, ½ new !
→ SEPARATING DNA STRANDS
H-bonds and twisting hold the strands together
DNA Helicase
Unwinds helix by breaking H-bonds between complementary base pairs.
- Point where two strands separate is replication fork
- Enrichment : one template strand runs 5’ → 3’ and the 3’ to 5’
⭐︎Helicase Enzyme unzips DNA
Building Complementary Strands
New strands synthesized by DNA polymerase enzyme.
- Link together free nucleotides (from food you eat)
