Bio Exam DNA Review 1

Question 1

What is the structure of DNA

Answer 1

It is Double Stranded Helix,Strands are Anti-Parallel, the strands run in opposite directions

Question 2

What are the Complementary Base Pairing Rules?

Answer 2

A=T. A and T are held together by two Hydrogen Bonds. G=C. G and C are held together by three hydrogen bonds. DNA has uniform width.

Question 3

Where are the bases located?

Answer 3

On the inside

Question 4

Where are the Phosphates Located?

Answer 4

On the outside

Question 5

How long is DNA?

Answer 5

DNA is three rings wide

Question 6

5^1 GTAACG 3^13^1 CATTGC 5^1

Answer 6

5^1 GTAACG 3^13^1 CATTGC 5^1

Question 7

What enzyme replicates DNA?

Answer 7

DNA Polymerase

Question 8

How does Polymerase work?

Answer 8

Polymerase only works 5 prime to 3 prime

Question 9

EKARYOTES:

Answer 9

Can make DNA about 2000 bases a min we are slowed down because we packaged DNA. Humans have thousands origins of replication

Question 10

PROKAYOTES

Answer 10

Can make DNA at 50,000 basses a min, prokaryotes have one origin of replication.

Question 11

What does Helicase do?

Answer 11

It unwinds DNA and puts it into a single stranded form.

Question 12

What do Single Stranded Binding Proteins (SSBP) do?

Answer 12

They Keep DNA in sing stranded form.

Question 13

What does Primase do?

Answer 13

It is going to ad a primer to the DNA and it is made up of RNA and not DNA

Question 14

What is DNA Polymerase and what is its function?

Answer 14

is the enzyme that makes the DNA, it is only going to make DNA 5 prime to 3 prime.

Question 15

What is Topoisomerase?

Answer 15

Is the enzyme that releases the stress on the DNA.

Question 16

What is the function of DNA Ligase?

Answer 16

It connects the Okazaki fragments together

Question 17

How do DNA Polymerase Proof Read?

Answer 17

by going 3 prime to 5 prime.

Question 18

Mature Messenger RNA

Answer 18

5^1 Gcap/3^1 poly A tail. (The tail can be up to 250 A’s in length) in the center we are going to have a open reading reign which is bound by a start codon and a stop codon.

Question 19

Does messenger RNA code for all protein?

Answer 19

No it only codes for some of it

Question 20

What is an INTRON?

Answer 20

A intron is going to intervene we are going to throw them out. They are going to be thrown out with what is referred to as a splicing reaction in which we are going to take the intron and cut them out and connect the exons together. (This only occurs in Eukaryotes)

Question 21

What happens once introns are removed?

Answer 21

Once the introns are removed we add the 5 prime Gcap and the 3 prime poly A tail.

Question 22

What are the three reasons why we need the? 5^1Gcap 3^1 poly A tail.

Answer 22

So we know we are finished (transcription is finished)Transportation out of the Nucleus To prevent degradation

Question 23

What happens to the Exon?

Answer 23

It Is expressed so we are going to keep it.

Question 24

Aminoacytle rTRNA synthase

Answer 24

adds an amino acids on to transfer RNA

Question 25

The single stranded regions of tRNA have importance because?

Answer 25

• The 3 prime has the sequence CCA and binds to the amino acid, this is where the aminoacyl tRNA synthases adds the amino acid on to the transfer RNA • The T loop allows transfer RNA to set into the ribosome properly , this is how it is going to get into the A site of the ribosome. • The bottom is the anticodon this is going to base pair with the codon on the messenger RNA • The D loop allows for the aminoacyl tRNA synthases to add to the enzyme properly, to interact with it so we can add the amino acid.

Question 26

Definition of Gene?

Answer 26

Functional units of DNA that code for the aa sequence in one or more polypeptide chains, or for one of several types of RNA that do not form a protein (tRNA = Transfer RNA, rRNA = Ribsomial RNA, snRNA = small nuclear RNA, and microRNA)

Question 27

What is a promoter?

Answer 27

is the location DNA which h tell you where transcription is going to occur, and it is bound by RNA Polymerase. Promoter occurs upstream.

Question 28

How is RNA Made?

Answer 28

5 prime to 3 prime

Question 29

Which strand is used to make

Answer 29

We could use either the top strand or the bottom strand.

Question 30

What type of RNA do we make the most of?

Answer 30

Ribosomal RNA (rRNA)

Question 31

How are Ribosomes made?

Answer 31

Ribosomes are made is two separate parts: small subunit and a large subunit. Each one consisting of ribosomal RNA and ribosomal proteins, they have to be kept separate until they are going to be used. This is where protein synthesis occurs

Question 32

What is tRNA?

Answer 32

tRNA is referred to as the adaptor molecule, it adpats because we are changing the system. This is going to allow us to bring in amino acids.

Question 33

The adaptation that takes place in transfer RNA is that it allows us to change from a base to base pairing scheme to a base to amino acid pairing scheme

Answer 33

The adaptation that takes place in transfer RNA is that it allows us to change from a base to base pairing scheme to a base to amino acid pairing scheme

Question 34

What is the Anticodon a part of?

Answer 34

Transfer RNA

Question 35

What is the Codon a part of?

Answer 35

Messenger RNA

Question 36

What does Messenger RNA Consist of?

Answer 36

Messenger RNA consists of bases and Proteins consist of amino acids.

Question 37

What does Messenger RNA contain?

Answer 37

Messenger RNA contains the message for the protein it tells you what proteins you are supposed to make

Question 38

TRANSCRIPTION

Answer 38

Initiation TF = Transcription Factors TF binds to TATA box in the promoter RNA polymerase bind Remaining TFs bind All three of these step must be completed Elongation Here we are going to make RNA) RNA polymerase runs down the double stranded DNA and makes a strand of RNA reading the bottom of DNA strand. Follows the complementary base pairing rules ``` DNA RNA --------- ---------- A U C G G C T A ``` Termination Process continues until termination signal is reached and RNS polymerase is bumped off the DNA realing the completed RNA transcript

Question 39

TRANSLATION

Answer 39

Initiation 1 Three substances come together, small subunit of the ribosome binds messenger RNA which binds to the initiator trRNA 2 This complex is joined by the Large ribosomal subunit ELONGATION 1. Translation begins at an AUG and ends at UAA,UAG, or UGA 2. P site holds growing protein chain attached to tRNA. It is held in place through complementary binding of its anti codon with the codon on the mRNA 3. A site accepts the next tRNA with the new A.A 4. Proteins forms covalent peptide bond with new A.A 5. Everything moves down 3 bases 6. Old A site is ne P site 7. New A site awaits for the next tRNS Termination 1 elongation continues until stop codon reached 2 release factor binds does not call for AA 3 protein is released from the ribosome 4 ribosome falls apart