Nucleotides, Nucleic Acids, and Heredity

Question 1

From the end of the 19th century, biologists suspected that the transmission of hereditary information took place in the nucleus

Answer 1

chromosomes

Question 2

Chemical analysis of nuclei showed chromosomes are made up largely of proteins called

Answer 2

histones and nucleic acids.

Question 3

By the 1940s, it became clear that (Blank) carry the hereditary information

Answer 3

deoxyribonucleic acids (DNA)

Question 4

two kinds of nucleic acids in cells

Answer 4

Ribonucleic acids (RNA) & Deoxyribonucleic acids (DNA)

Question 5

is composed of:
A base, a monosaccharide, and a phosphate

Answer 5

nucleotides

Question 6

A compound that consists of D-ribose or 2-deoxy-D-ribose bonded to a purine or pyrimidine base by a -N-glycosidic bond.

Answer 6

Nucleoside

Question 7

A nucleoside in which a molecule of phosphoric acid is esterified with an –OH of the monosaccharide, most commonly either at the 3’or the 5’–OH.

Answer 7

Nucleotide

Question 8

serves as a common currency into which energy gained from food is converted and stored.

Answer 8

Adenosine 5’-triphosphate (ATP)

Question 9

is the sequence of nucleotides, beginning with the nucleotide that has the free 5’ terminus.
( strand read from the 5’end to the 3’end)

Answer 9

primary structure

Question 10

The ordered arrangement of nucleic acid strands.

Answer 10

Secondary structure

Question 11

A type of 2° structure of DNA in which two polynucleotide strands are coiled around each other in a screw-like fashion.
- structure was proposed by James Watson and Francis Crick in 1953.

Answer 11

Double helix

Question 12

pair by forming two hydrogen bonds.

Answer 12

Adenine and Thymine

Question 13

pair by forming three hydrogen bonds

Answer 13

Guanine and Cytosine

Question 14

DNA is coiled around proteins

Answer 14

histones.

Question 15

A core of eight histone molecules around which the DNA helix is wrapped.

Answer 15

Nucleosome

Question 16

Chromatin fibers are organized into loops, and the loops into the bands that provide the superstructure of __________.

Answer 16

chromosomes.

Question 17

Transport amino acids to site of protein synthesis.

Answer 17

tRNA

Question 18

Combines with proteins to form ribosomes, the site of protein synthesis.

Answer 18

rRNA

Question 19

Directs amino acids sequence of proteins.

Answer 19

mRNA

Question 20

process initials mRNA to its mature from in eukaryotes

Answer 20

snRNA (Small nuclear RNA)

Question 21

Affects gene expression; important product in growth and development

Answer 21

miRNA ( Micro RNA)

Question 22

The sequence of bases in DNA is recorded as sequence of complementary bases in a single-stranded mRNA molecule.

Answer 22

Transcription

Question 23

Three base codons on the mRNA corresponding to specific amino acids direct to the sequence of building a protein. Theses codons are recognized by tRNA carrying the appropriate amino acid.

Answer 23

Transcription

Question 24

A segment of DNA that carries a base sequence that directs the synthesis of a particular protein, tRNA, or mRNA.

Answer 24

Gene

Question 25

A section of DNA that, when transcribed, codes for a protein or RNA.

Answer 25

Exon

Question 26

A section of DNA that does not code for anything functional.

Answer 26

Introns

Question 27

The process that reproduces itself. It supplies the information necessary to make all the RNA and proteins in the body, including enzymes.

Answer 27

Replication

Question 28

Replication begins at a point in the DNA called the origin of replication or a ________.

Answer 28

Replication Fork

Question 29

This reaction eliminates some of the positive charges on histones and weakens the strength of the DNA-histone interaction.

Answer 29

acetylation-deacetylation of lysine residues on histones.

Question 31

temporarily introduce either single- or double-strand breaks in DNA.

Answer 31

Topoisomerases (also called gyrases)

Question 32

Special unwinding proteins. -attach themselves to one DNA strand and cause the separation of the double helix.

Answer 32

Helicases

Question 33

are short—4 to 15 nucleotides long—RNA oligonucleotides synthesized from ribonucleoside triphosphates

Answer 33

Primers/Primases

Question 34

the DNA nucleotides must be lined up. In the absence of DNA polymerases, this alignment is extremely slow. The enzyme enables complementary base pairing with high specificity. While bases are being hydrogen bonded to their partners, polymerases join the nucleotide backbones.

Answer 34

DNA Polymerase

Question 35

Along the lagging strand 3’—>5”, the enzymes can synthesize only short fragments, because the only way they can work is from 5’ to 3’.

Answer 35

Okazaki fragments

Question 36

The Okazaki fragments and any nicks remaining are eventually joined by DNA ligase.

Answer 36

Ligation

Question 37

DNA fragments can be made within a few hours with high precision by a technique called

Answer 37

polymerase chain reaction (PCR)

Question 38

are polynucleotides consisting of 12 to 16 nucleotides.

Answer 38

primers