DNA Replication and the Central Dogma Flashcards
Define genetics:
The science of heredity, how traits are passed from generation to generation
Define genome:
The sum total of genetic information (DNA) in a cell
Define Chromosomes:
Structures that contain DNA
Define Genes:
Segments of DNA (generally) that code for functional products
Define Genotype:
The genes of an organism (potential properties)
Define Phenotype:
Actual expressed properties (phenotype is the manifestation of genotype)
Bacterial chromosome: Length of E. coli chromosome?
About 1 mm
Bacterial chromosome: Length of the E. coli cell?
2 um
Bacterial chromosome: Number of genes?
4288
Bacterial chromosome: Number of base pairs?
About 5 million
Bacterial chromosome: how many chromosomes and what shape?
One circular chromosome
Bacterial chromosome: Does it have potential to contain plasmids?
Yes
Bacterial chromosome: Is it super coiled?
Yes
Human Genome: Length of chromosome?
About 6 feet long
Human Genome: Length of a human cell?
40 um
Human Genome: Number of genes?
20,000-25,000
Human Genome: Number of base pairs?
About 3 billion
Human Genome: How many chromosomes?
46 chromosomes
Human Genome: Is it super coiled?
Yes
The Central Dogma=
In cellular beings, the genetic information is contained in DNA. When the cell wants to make protein, it copies the information from the DNA into RNA and uses that RNA to translate it into proteins
DNA: Is the genetic code of information known as the “blueprint”?
Yes
DNA is informational…
storage on a cellular level
DNA: Do each cell have the same DNA?
Yes, Eukaryotes: Liver cell= same DNA as heart cell
Prokaryotes
DNA Structure: Who is credited for the structure of DNA?
James Watson and Francis Crick. They won the nobel prize for constructing a 3-D structure of DNA
DNA Structure: Who noted that DNA must have deoxyribose, phosphate, purines, and pyrimidines?
Edward (Erwin) Chargaff
DNA Structure: What is Rosalind Franklin known for?
X-ray crystallography
Units of DNA nucleotides: They are the basic units of DNA and consist of
Phosphate (backbone of DNA)
Deoxyribose sugar (alternates with phosphate and is also a part of the backbone)
Nitrogenous base
A single strand of DNA contains what kind of structure?
two 2-ring structures and two 1-ring structures
Why is it important for the two strands to be the same length apart?
You’ll end up with a two ring structure bound to a one ring structure
What do “A” and “G” always bind to?
Purines (acronym: “Always use PURE Gold”)
What do “C” and “T” always bind to?
Pyrimidines
Is DNA double or single stranded?
Double
What are DNA strands held together by?
DNA strands are held together by hydrogen bonds between A-T and C-G
Describe the strands
Directional
Antiparallel
Complementary
What does “DNA strands are directional” mean?
The “backbone” is deoxyribose-phosphate.
You start at the Carbon 5 of the first sugar:
PO4-5’-3’PO4-5’-3’-PO4-5’-3’-OH
This is referred to as the 5’-3’ direction
What does “DNA strands are antiparallel” mean?
The two strands of DNA have OPPOSITE chemical polarity
Sugar-phosphate backbones run in OPPOSITE directions
Direction in nucleic acids is specified by referring to the carbons of the ribose ring in the sugar-phosphate backbone of DNA
(Basically, if one strand is going in the 5’-3’ then the second strand is going in the 3’-5’. The strand going in the 3’-5’ is the strand we don’t read because we only read DNA strands that go in the right direction…5’-3’)
What does “DNA strands are complementary” mean?
Base paring rules say that “A” shall always pair with “T”
Base pairing
“A” always pairs with “T”-
2 hydrogen bonds connect the two
“G” always pairs with “C”-
3 hydrogen bonds connect the two
So…G/C base pair is STRONGER than an A/T base pair
