Genetics Chapter 6

Question 1

What was the purpose of the Hershey and Chase experiment?

Answer 1

Determine the hereditary material of cells, proteins or DNA?

Question 2

When a virus infects bacteria, it will inject what kind of info into the bacteria? What does this do?

Answer 2

Hereditary info gets injected. This instructs the bacteria to make more virus.

Question 3

P32 is radioactive ________ found in DNA. S55 is radioactive _______ found in protein.

Answer 3

phosphorus. sulfur.

Question 4

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?

Answer 4

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).

Question 5

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.

Answer 5

2, twice, DNA

Question 6

The monomer of DNA is a _________. It includes which 3 things?

Answer 6

nucleotide: nitrogen base, 5-carbon sugar and a phosphate group.

Question 7

When DNA is made, what does a standard nucleotide lose?

Answer 7

2 phosphate groups

Question 8

Which bond holds nucleotides together? Which bond holds nitrogen base strands together?

Answer 8

Nucleotides: phosphodiester
Strands: Hydrogen bonds

Question 9

In DNA, there are 4 bases. How are they paired? How is this different in RNA?

Answer 9

A-T (adenine and thymine), C-G (cytosine and guanine). In RNA, adenine pairs with uracil instead of thymine

Question 10

Which carbon determines the sugar of a nucleic acid? What is it if there is an OH? An H?

Answer 10

C3. OH: ribose, H: deoxyribose

Question 11

Use the words complementary and antiparallel to describe DNA.

Answer 11

DNA uses complementary base pairing, but the two strands run in opposite directions (antiparallel)

Question 12

There are roughly ________ nucleotides that code for _______ genes.

Answer 12

3 billion nucleotides, 30,000 genes

Question 13

Which carbon is always outside of the ring? Phosphodiester bonds are always made between which two carbons?

Answer 13

C5, bonds made between C3 and C5

Question 14

Which carbon does the nitrogenous base always attach to?

Answer 14

C1

Question 15

Which bases are purines? Which are pyrimidines? How do you remember?

Answer 15

Pyrimidines: CUT the PY (cytosine, uracil, thymine)
Purines: pure as two gold rings: adenine and guanine

Question 16

How can you decipher which bases are which?

Answer 16

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.

Question 17

What is DNA?

Answer 17

A molecule that carries the genetic code for all organisms

Question 18

Describe the three different types of RNA?
mRNA: carries info from….
tRNA: adapter between 3 bases of codon….
rRNA: binds w proteins to form….

Answer 18

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

Question 19

Template strand is read in the ___ to ___ direction, and the daughter is made in the opposite direction, ___ to ___.

Answer 19

template: read 3’ to 5’
daughter: made 5’ to 3’

Question 20

DNA replication is semi-conservative (takes 1h) What does this mean? In conservative, what happens to the parent strand?

Answer 20

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.

Question 21

What is the difference between the starting point of DNA replication, and the point of separation?

Answer 21

Starting point is known as the origin, and the point of separation is the replication fork

Question 22

Which enzyme unzips parent strands at the origin?

Answer 22

Helicase

Question 23

What does topoisomerase do?

Answer 23

It relieves tension caused by the unwinding of parent DNA

Question 24

RNA primase is an enzyme that adds a very short piece of ___ _______ at the ____ end of the parent strand. When is it applied?

Answer 24

RNA primer, 3’, it is applied before a daughter strand is built

Question 25

Which enzyme reads the parent strand 3’ to 5’, but builds the daughter strand? Which direction is new DNA built?

Answer 25

DNA polymerase 3. It is built in the 5’ to 3’ direction

Question 26

What is the function of DNA polymerase 1? (It removes ______ and fills the spaces with _____)

Answer 26

It removes RNA primer from the daughter strand and adds new DNA

Question 27

DNA ligase creates which bond between new pieces of daughter DNA?

Answer 27

phosphodiester

Question 28

What is continuous replication? What kind of strand does it built? What does discontinuous replication build?

Answer 28

The addition of nucleotides, added one by one in the direction of the replication fork. It builds the leading, opposite builds the lagging.

Question 29

What are Okazaki fragments?

Answer 29

Pieces of DNA made in discontinuous replication

Question 30

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.

Answer 30

primers, lagging, polymerase 1, primers, ligase

Question 31

Every time CODING DNA is replicated, it becomes shorter by 1 _____ length. ________ are a repeating sequence of DNA that protects ______ regions from being lost.

Answer 31

primer, telomeres, coding

Question 32

Which enzymes scan for mistakes in DNA replication?

Answer 32

DNA polymerase 1 and 2