Genetics Chapter 6 Flashcards
What was the purpose of the Hershey and Chase experiment?
Determine the hereditary material of cells, proteins or DNA?
When a virus infects bacteria, it will inject what kind of info into the bacteria? What does this do?
Hereditary info gets injected. This instructs the bacteria to make more virus.
P32 is radioactive ________ found in DNA. S55 is radioactive _______ found in protein.
phosphorus. sulfur.
In the Hershey-Chase experiment, virus injected something into the bacteria. What was the purpose of the blender step? What was the purpose of the centrifuge step?
Blender: to separate the virus from the bacteria. Centrifuge: to separate the heavy bacteria from the light virus (bacteria goes to bottom, virus stays on top).
There were ____ blended solutions and so the centrifuge was used ______. Since radioactivity was found in the bacteria at the bottom when P32 was injected, they determined _____ was the hereditary material.
2, twice, DNA
The monomer of DNA is a _________. It includes which 3 things?
nucleotide: nitrogen base, 5-carbon sugar and a phosphate group.
When DNA is made, what does a standard nucleotide lose?
2 phosphate groups
Which bond holds nucleotides together? Which bond holds nitrogen base strands together?
Nucleotides: phosphodiester
Strands: Hydrogen bonds
In DNA, there are 4 bases. How are they paired? How is this different in RNA?
A-T (adenine and thymine), C-G (cytosine and guanine). In RNA, adenine pairs with uracil instead of thymine
Which carbon determines the sugar of a nucleic acid? What is it if there is an OH? An H?
C3. OH: ribose, H: deoxyribose
Use the words complementary and antiparallel to describe DNA.
DNA uses complementary base pairing, but the two strands run in opposite directions (antiparallel)
There are roughly ________ nucleotides that code for _______ genes.
3 billion nucleotides, 30,000 genes
Which carbon is always outside of the ring? Phosphodiester bonds are always made between which two carbons?
C5, bonds made between C3 and C5
Which carbon does the nitrogenous base always attach to?
C1
Which bases are purines? Which are pyrimidines? How do you remember?
Pyrimidines: CUT the PY (cytosine, uracil, thymine)
Purines: pure as two gold rings: adenine and guanine
How can you decipher which bases are which?
Adenine: (add) give us another double bond at the N! We want three! (people yelling at a restaurant)
Cytosine: (sigh) we only have one double bond at the N. Can we get more?
Uracil looks like a funny face with two “NH” eyes.
What is DNA?
A molecule that carries the genetic code for all organisms
Describe the three different types of RNA?
mRNA: carries info from….
tRNA: adapter between 3 bases of codon….
rRNA: binds w proteins to form….
mRNA: carries info from DNA to ribosomes where protein is made
tRNA: adapter between 3 bases of codon and corresponding amino acid
rRNA: binds w proteins to form ribosomes
Template strand is read in the ___ to ___ direction, and the daughter is made in the opposite direction, ___ to ___.
template: read 3’ to 5’
daughter: made 5’ to 3’
DNA replication is semi-conservative (takes 1h) What does this mean? In conservative, what happens to the parent strand?
Two strands of the parent DNA form two templates. A daughter strand is made from each of the templates. It stays together, two completely new strands made.
What is the difference between the starting point of DNA replication, and the point of separation?
Starting point is known as the origin, and the point of separation is the replication fork
Which enzyme unzips parent strands at the origin?
Helicase
What does topoisomerase do?
It relieves tension caused by the unwinding of parent DNA
RNA primase is an enzyme that adds a very short piece of ___ _______ at the ____ end of the parent strand. When is it applied?
RNA primer, 3’, it is applied before a daughter strand is built
Which enzyme reads the parent strand 3’ to 5’, but builds the daughter strand? Which direction is new DNA built?
DNA polymerase 3. It is built in the 5’ to 3’ direction
What is the function of DNA polymerase 1? (It removes ______ and fills the spaces with _____)
It removes RNA primer from the daughter strand and adds new DNA
DNA ligase creates which bond between new pieces of daughter DNA?
phosphodiester
What is continuous replication? What kind of strand does it built? What does discontinuous replication build?
The addition of nucleotides, added one by one in the direction of the replication fork. It builds the leading, opposite builds the lagging.
What are Okazaki fragments?
Pieces of DNA made in discontinuous replication
Fill in the gaps for discontinuous replication.
As the parent strand unzips, more ______ are placed along the ______ strand. DNA __________ __ removes the _____. DNA _____ fills in the gaps.
primers, lagging, polymerase 1, primers, ligase
Every time CODING DNA is replicated, it becomes shorter by 1 _____ length. ________ are a repeating sequence of DNA that protects ______ regions from being lost.
primer, telomeres, coding
Which enzymes scan for mistakes in DNA replication?
DNA polymerase 1 and 2
