Exam 2 Biology pt.1

Question 1

Nucleotides are made up of?

Answer 1

Nucleotides are made up of a
1. Phosphate
2. 5 Carbon sugar
3. Nitrogenous base

Question 2

5 Carbon Sugar

Answer 2

The two most important Carbons to be aware of in this sugar are the 5’ and the 3’
Remember that the Oxygen molecules point in the 5’ direction

Question 3

Nitrogenous bases

Answer 3

4 kinds of nitrogenous bases in DNA, make nucleotides unique from one another

Question 4

The 4 Nitrogenous Bases (+1)

Answer 4

Adenine (A)
Cytosine (C)
Guanine (G)
Thymine (T) (DNA)
Uracil (U) (RNA)

Question 5

Two groups of nitrogenous bases: Purines

Answer 5

Adenine (A) and Guanine (G)

Question 6

Two (+1) groups of nitrogenous bases: Pyrimidines

Answer 6

Cytosine (C), Thymine (T) (DNA) and Uracil (U) (RNA)

Question 7

Purine: Molecular Configuration (Two Ring or One ring)

Answer 7

Two Rings

Question 8

Pyrimidines: Molecular Configuration (Two Ring or One ring)

Answer 8

One Ring

Question 9

Structure of a DNA Molecule: NucleosideTriphosphates (dNTPs)

Answer 9

the building blocks of DNA

Question 10

Structure of a DNA Molecule: phosphodiester bond (Strong Covalent bond)

Answer 10

the alpha phosphate on the tri-phosphate (closest to the sugar molecule) covalently binds to the 3’ sugar on the adjacent nucleotide. The other two phosphates are lost. This bond is called a phosphodiester bond

Question 11

3D structure of DNA

Answer 11

forms a double helix: two intertwined, antiparallel, complimentary strands of DNA.

Question 12

How does DNA get this structure?

Answer 12

Adenine binds to thymine using two hydrogen bonds (A-T). While Guanine binds to cytosine using three hydrogen bonds (G-C)

Question 13

Are hydrogen bonds strong?

Answer 13

no, weak

Question 14

Which of these two pairs has a stronger bond? (A-T) OR (G-C)

Answer 14

G-C are stronger than A-T

Question 15

Chargaff’s Rule

Answer 15

Number of A = Number of T
Number of G = Number of C

Question 16

Chargaff’s Rule (2)

Answer 16

if 40% are A, 40% must be T. This means the 0ther 20% must be half G and half C (10%-10%)

Question 17

Structure of DNA- two strands run…?

Answer 17

Anti-parallel

Question 18

What is the purpose of the Central Dogma

Answer 18

Biological information is stored in DNA, transcribed, then translated into proteins

Question 19

What is Transcription:

Answer 19

Complementary strand of RNA synthesized (but U instead of T)

Question 20

What is Translation:

Answer 20

Protein synthesized from RNA.

Question 21

DNA Replication: Origin

Answer 21

start site for replication

Question 22

DNA Replication: Initiator protein

Answer 22

recognize origin (opens up the DNA)

Question 23

Replication: Single-stranded template

Answer 23

Helicase and Topoisomerase

Question 24

Helicase

Answer 24

break hydrogen bonds, separate strands “unzip”

Question 25

Topoisomerase

Answer 25

remove tension from coiled DNA

Question 26

Primer: RNA Primer

Answer 26

This primer will be the start of a new strand of DNA. This RNA primer is created using the enzyme primase

Question 27

DNA Polymerase III

Answer 27

Starting at the primer, DNA Polymerase III makes a complementary strand of DNA. Adds new nucleotides to the 3’ of the molecule and only works in the 3’ to 5’ direction

Question 28

DNA Polymerase III: DNA Replication

Answer 28

will add base pairs to the end of the RNA primer until replication is complete and DNA Polymerase I cleaves off the RNA molecule.

Question 29

DNA Polymerase I and DNA Ligase

Answer 29

DNA Polymerase I removes the RNA Primers and Replaces them with DNA
DNA Ligase joins the fragments together