Chapter 8

Question 1

Gene

Answer 1

A segment of a DNA molecule that contains the information required
for the synthesis of a functional biological product, whether protein or RNA

Question 2

________ are components of ribosomes, the complexes that carry out the synthesis of proteins.

Answer 2

Ribosomal RNAs (rRNAs)

Question 3

_________ are intermediaries, carrying information for the synthesis of a
protein from one or a few genes to a ribosome

Answer 3

Messenger RNAs (mRNAs)

Question 4

___________ adapter molecules that faithfully translate the information in mRNA into a specific sequence of amino acids

Answer 4

Transfer RNAs (tRNAs)

Question 5

___________ and Nucleic Acids Have Characteristic Bases and Pentoses

Answer 5

Nucleotides

Question 6

A nucleotide has 3 characteristic, what are they?

Answer 6

1. A nitrogenous base
2. A pentose
3. One or more phosphates

Question 7

________ is a molecule without a phosphate group but has a nitrogenous base & pentose is what?

Answer 7

Nucleoside

Question 8

The nitrogenous bases are derivatives of what two parent compounds?

Answer 8

1. Pyrimidine
2. Purine

Question 9

Nucleobase is a ________ nitrogenous base

Answer 9

Heterocylic

Question 10

The base of a nucleotide is joined covalently at _______ of pyrimidines & ______ of purines

Answer 10

N-1, N-9 & in pentose at C1 & in phosphate at C5

Question 11

Both DNA & RNA both contain the purines bases such as _______ & _____

Answer 11

Adenine (A) & Guanine (G)

Question 12

Both DNA & RNA contain the pyrimidines base _______

Answer 12

Cytosine (C)

Question 13

Thymine is also a pyrimidine base but found in _____

Answer 13

DNA

Question 14

Uracil is also a pyrimidine base but found in ______

Answer 14

RNA

Question 15

2’-deoxy-D-ribose is the pentose for _______

Answer 15

DNA

Question 16

D-ribose is the pentose for _____

Answer 16

RNA

Question 17

Both DNA & RNA have pentose in a _________ form

Answer 17

β-furanose (closed five-membered ring) form

Question 18

Both DNA & RNA have pentose in a _________ form

Answer 18

β-furanose (closed five-membered ring) form & they are “puckered”

Question 19

Prime numbers distinguish _____________ numbering

Answer 19

sugar & base

Question 20

Nucleobases are derivatives of _________ & ___________

Answer 20

Pyrimidine or purine

Question 21

___________ Bonds Link Successive Nucleotides in Nucleic Acids

Answer 21

Phosphodiester

Question 22

The successive nucleotides of both DNA and RNA are covalently linked
through phosphate-group “bridges,” in which the 5′-phosphate group of one
nucleotide unit is joined to the 3′-hydroxyl group of the next nucleotide,
creating a ________________

Answer 22

phosphodiester linkage

Question 23

The properties of nucleotide bases affect the 3-D structure of __________

Answer 23

Nucleic Acids

Question 24

Nucleobases are planar structures which asborb UV light around __________

Answer 24

250-270nm

Question 25

Nucleobases vary in polar groups which is based on their tautomeric form where you have to identify their ______ & _______

Answer 25

Hydrogen bond donors & acceptors

Question 26

Chargaff's rule

Answer 26

Was a key to establishing the three-dimensional structure of DNA and yielded clues to how genetic information is encoded in DNA and passed from one generation to the next

Question 27

What is chargaff rule?

Answer 27

1. The base composition of DNA generally varies from one species to another. 2. DNA specimens isolated from different tissues of the same species have the same base composition. 3. The base composition of DNA in a given species does not change with an organism’s age, nutritional state, or changing environment. 4. In all cellular DNAs, regardless of the species, the number of adenosine residues is equal to the number of thymidine residues (that is, A = T), and the number of guanosine residues is equal to the number of cytidine residues (G = C). From these relationships it follows that the sum of the purine residues equals the sum of the pyrimidine residues; that is, A + G = T + C.

Question 28

Describe DNA structure in a 2D sense

Answer 28

DNA molecules are helical, with two periodicities along their long axis, a primary one of 3.4 Å and a secondary one of 34 Å.

Question 29

Describe the 3D structure of DNA

Answer 29

1. It consists of two helical DNA chains wound around the same axis to form a right-handed double helix 2. The hydrophilic backbones of alternating deoxyribose and phosphate groups are on the outside of the double helix, facing the surrounding water. 3. The furanose ring of each deoxyribose is in the C-2′ endo conformation. 4. The purine and pyrimidine bases of both strands are stacked inside the double helix, with their hydrophobic and nearly planar ring structures very close together and perpendicular to the long axis.

Question 30

The offset pairing of the two DNA strands forms ________ & ________ groove

Answer 30

Major groove & minor groove

Question 31

G & C has ____ H-bonds & A & T has ____ H bonds

Answer 31

3,2

Question 32

DNA strands run ____________ to each other in a 3', 5', - phoshodiester

Answer 32

Antiparallel

Question 33

The two DNA strands are ______________ to each other

Answer 33

Complementary

Question 34

The DNA double helix is held together by ________ between complementarybase pairs

Answer 34

H bonds

Question 35

The double helix is primarily stabilized by ____________, which shield the negative charges of backbone phosphates, and by base-stacking interactions between complementary base pairs.

Answer 35

metal cations

Question 36

Base-stacking interactions between adjacent G≡C pairs are stronger than those between adjacent A=T pairs or adjacent pairs including all four bases. Because of this, DNA duplexes with higher G≡C content are more __________.

Answer 36

stable

Question 37

What is the equation verison of Chargaff rule?

Answer 37

A + G = C + T (A-U are base pairs in RNA)

Question 38

What is the equation verison of Chargaff rule?

Answer 38

A + G = C + T (A-U are base pairs in RNA) (purine pairs with pyrimidine)

Question 39

A-T and G-C base pair are_________ to helix axis

Answer 39

perpendicular

Question 40

In the watson & crick model of B form DNA it shows that the bases are stack on top of each other & that they are distance by _____ angstroms & the strands are _____ angrtsom long with a heical turn of _____ angstrom

Answer 40

3.4, 20, 10.5

Question 41

__________________ of DNA Strands allows each strand to serve as a template for the synthesis of new strands

Answer 41

Complementarity

Question 42

Pyrimidines are generally restricted to the _______________ because of steric interference between the sugar and the carbonyl oxygen at C-2 of the pyrimidine

Answer 42

anti-conformation

Question 43

The Watson & crick structure of DNA is referred to as _________ DNA

Answer 43

B-Form DNA (most stable form of DNA)

Question 44

What are the 3 forms of DNA?

Answer 44

A form, B form, Z form

Question 45

A common type of DNA sequence is a _____________

Answer 45

palindrome

Question 46

A _____________ is a word, phrase, or sentence that is spelled identically when read either forward or backward; two examples are ROTATOR and NURSES RUN

Answer 46

palindrome

Question 47

In DNA palindrome is a term applied to regions of DNA with _________, such that an inverted, self-complementary sequence in one strand is repeated in the opposite orientation in the paired strand

Answer 47

inverted repeats

Question 48

The self-complementarity within each strand confers the potential to form __________ or cruciform (cross-shaped) structures

Answer 48

hairpin

Question 49

Mirror repeat

Answer 49

When the inverted repeat occurs within each individual strand of the DNA

Question 50

____________ do not have complementary sequences within the same strand and thus cannot form hairpin or cruciform structures

Answer 50

Mirror repeats

Question 51

Messenger RNAs Code for _______________ Chains

Answer 51

Polypeptide

Question 52

In eukaryotes, most mRNAs are _______________

Answer 52

monocistronic

Question 53

Monocistronic mRNA

Answer 53

Carries the code for only one polypeptide

Question 54

Double helical DNA & RNA can be ______________-

Answer 54

Denatured

Question 55

DNA ______________ occurs when hydrogen bonds are broken and strands separate

Answer 55

Denaturation

Question 56

During DNA denaturation the genetic doe remains intact & base stacking is lost, UV absorbance _________ due to the hyperchromic effect

Answer 56

Increase

Question 57

DNA denaturation is induced by _______________________

Answer 57

high temperatures or pH

Question 58

Denaturation of a double-stranded nucleic acid produces the opposite result: an increase in absorption which is called the ____________ effect

Answer 58

Hyperchromic

Question 59

__________________ is the process where a denature DNA reforms to its double stranded DNA

Answer 59

Annealing

Question 60

What is the process of annealing?

Answer 60

Seperated strand of DNA are associated by base pairs to form a partially denature DNA into a double helical DNA

Question 61

The midpoint of melting (Tm) depends on base _______________ & DNA length (longer DNA higher Tm), & on pH & ionic strength (high salt increase Tm)

Answer 61

Composition (high CG increases Tm)

Question 62

At rich regions ______ at a lower temp than GC rich regions

Answer 62

Melt

Question 63

Nucleotides and Nucleic Acids Undergo ____________________

Answer 63

Nonenzymatic Transformations

Question 64

Mutations

Answer 64

Alterations in DNA structure that produce permanent changes in the genetic information encoded

Question 65

Deamination

Answer 65

Nucleotide bases undergo spontaneous loss of their exocyclic amino groups