Studied by 7 people
transformation
process where 1 strain of bacteria is changed by genes from another strain of bacteria
Bacteriophage
virus that infects bacteria
bacteriophage attaches to the surface of the bacterial cell and injects its genetic information into it. The phage DNA is incorporated into the bacterial DNA and the phage uses the bacterial cell to produce new bacteriophages.
how bacteriophages work
to store, copy, and transmit genetic information in a cell
DNA's roles (3)
storing information
foremost job: contain all instructions for determining what and organism will be and the process of developing from a single cell to an adult.
copying information
before a cell divides it must make complete copy of every gene for the new cell.
transmitting information
genes must be transmitted from one generation to the next.
deoxyribonucleic acid
DNA stands for ___
nucleotides joined into long strands/chains by covalent bonds.
DNA is made of ___
nucleotides
Nucleic acids are made of ___
5 carbon sugar, a phosphate group, and a nitrogenous base
3 basic components of nucleotides
nitrogenous base
term for a base that contains nitrogen
adenine, thymine, cytosine, and guanine
DNA's 4 nitrogenous bases
the sugar group of one nucleotide and the phosphate group of the next nucleotide.
In DNA, covalent bonds form between ___
[A]=[T] and [C]=[G]; in DNA, the amount of adenine and thymine found are equal and the amount of cytosine and guanine are equal.
Chargaff's rule
double helix
the shape of DNA; 2 DNA molecules twist around each other like a ladder.
double helix explains
1.) Chargaff's rule of base pairing, 2.) how two strands are held together, and 3.) how DNA can function as a genetic carrier
anti-parallel strands
2 strands of DNA run in opposite directions
holds 2 strands of the double helix together; hydrogen bonds form only between certain nitrogenous bases. These weak bonds allow the structure to separate.
Why is hydrogen bonding in DNA important?
base pairing
What do we call the following: adenine pairs with thymine, cytosine pairs with guanine
Each base on one strand pairs with only one base on the opposite strand; each strand has information necessary to reconstruct the other half (strands are complementary)
how does base pairing in double helix explain how DNA can be copied?
replication
a copying process which duplicates the DNA
unzipping
a process (mediated by enzymes) which separates the two strands of DNA, allowing 2 replication forks to form.
unzipping the DNA, breaking the hydrogen bonds, and unwinding 2 strands
role of DNA Helicase enzymes in replication
DNA polymerase
enzyme that joins individual nucleotides to produce and proofread a new DNA strand.
telomeres
DNA at tips of chromosomes which is difficult to replicate
telomerase
an enzyme which helps replicate the telomere region by adding short repeated DNA sequences to telomeres; helps prevent genes from being damaged or lost
nucleosomes
beadlike structures of DNA and histones
in the S phase
When does DNA replication occur?
prokaryotic DNA replication
starts in a single spot and goes around in 2 directions until the entire chromosome is copied
eukaryotic DNA replication
begins at many different spots on the DNA molecule and proceeds in 2 directions until the entire chromosome is copied
Single - stranded binding protein
proteins that bind to the freshly split DNA molecule to keep the two strands apart.
Leading Strand
Strand of freshly copied DNA which is continuously made
Lagging strand
Strand of freshly copied DNA which is discontinuously made - resulting in fragments of DNA which will need to be strung together later.
Okazaki fragments
Disjointed pieces of DNA which are created on the lagging strand.
Alfred Hershey and Marsha Chase
Used radioactive materials on bacteriophages to see which material got passed on to bacteria cells, DNA or proteins. Found that DNA was the molecule responsible.
Oswald Avery
Scientist who, with his team, found the molecule which results in transformation by meticulously destroying one molecule at a time.
Frederick Griffith
Scientist who studied the r-strain and s-strain of bacteria and how it influenced mice.
GCAT
What would the complementary DNA strand be if the original strand's sequence is CGTA?
Rosalind Franklin
Scientist who conducted x-ray diffraction on DNA to discover it was a double helix shape
Watson and Crick
Scientists who first build a proper model of the DNA molecule
Erwin Chargaff
Scientist who discovered the amount of adenine and thymine are always equal, as well as the amounts of guanine and cytosine.
Circular
The shape of a bacteria cell's DNA
In the cytoplasm
Where a bacteria cell's DNA can be found
in the nucleus
Where a eukaryotic cell's DNA can be found.
Adenine and Guanine
The bases known as the purines.
Thymine and Cytosine
The bases known as the pyrimidines.
Uracil
uracil binds to adenine via two hydrogen bonds (replaces thymine)
Ribose
Carbohydrate
Phosphate Group
phosphate group is important in living things in different ways. Firstly, it is an important structural component of nucleotide, which is the basic structural unit of DNA and RNA. Secondly, it is a component of energy-rich molecules, such as ATP.
Nucleotide
a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.
Nucleic Acid
large biomolecules, essential to all known forms of life.
mRNA
Messenger RNA
