biochem nucleutides, nucleic acids and heredity Flashcards

1
Q

that the transmission of hereditary information took place in the nucleus, more specifically in structures called

A

chromosomes.

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2
Q

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

A

histones and nucleic acids.

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2
Q

The hereditary information was thought to reside in genes within the

A

chromosomes

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3
Q

By the 1940s, it became clear that ____carry the hereditary information

A

deoxyribonucleic acids (DNA

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3
Q

There are two kinds of nucleic acids in cells:

A
  • ribonucleic acids (RNA)
  • deoxyribonucleic acids (DNA)
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4
Q

*Purine

A

-Adenine (A)
-Guanine (G)

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4
Q

Both RNA and DNA are polymers built from monomers called

A

nucleotides.

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4
Q
  • There are two kinds of nucleic acids in cells:
A
  • ribonucleic acids (RNA)
  • deoxyribonucleic acids (DNA)
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5
Q

*Pyrimidine

A

-Cytosine (C)
-Thymine (T)
-Uracil (U)

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5
Q
  • A nucleotide is composed of
A

: a base, a monosaccharide, and a phosphate.

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6
Q

Nucleosides: composed of

A

base and monosaccharide

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7
Q

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

A
  • Nucleoside:
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8
Q

is esterified with an -OH of the monosaccharide

A

a nucleoside in which a molecule of phosphoric

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9
Q

a nucleoside in which a molecule of phosphoric

A

esterified with an -OH of the monosaccharide

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10
Q

-a nucleoside in which a molecule of phosphoric acid is esterified with an -OH of the monosaccharide, most commonly either the

A

3’ or the 5’-OH.

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10
Q

base sequence is read from the

A

5’ end to the 3’ end

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11
Q

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

A

adenosine 5’-triphosphate (ATP)

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12
Q

: the ordered arrangement of nucleic acid strands.

A

Secondary structure

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13
Q

a type of 2° structure of DNA in which two polynucleotide strands are coiled around each other in a screw-like fashion.

A
  • Double helix:
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14
Q

DNA is coiled around proteins called

A

histones.

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15
Q

Histones are rich in these basic amino acids

A

Lys and Arg

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16
Q

Lys and Arg

A

whose side chains have a positive charge.

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17
Q

The negatively-charged DNA molecules and positively-charged histones attract each other and form units called

A

nucleosomes

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18
Q

Nucleosomes are further condensed into

A

chromatin.

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19
Q

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

A

Nucleosome

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20
Q

Chromatin fibers are organized into

A

loops

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21
Q

DNA bases are

A

A, G, C,

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21
Q

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

A

chromosomes.

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21
Q

The sugar in DNA is

A

2-deoxy-D-ribose

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22
Q

T; the RNA bases are

A

A, G, C, and U

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22
Q
  • The three differences in structure between DNA and RNA are:
A
  • The three differences in structure between DNA and RNA are:
  • DNA bases are A, G, C, and T; the RNA bases are A, G, C, and U.
  • The sugar in DNA is 2-deoxy-D-ribose; in RNA it is D-ribose.
  • DNA is always double stranded; there are several kinds of RNA, all of which are single-stranded.
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23
Q

The sugar in RNA is

A

D-ribose.

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23
Q

DNA is always _____ stranded

A

double

24
Q

Small Transports amino acids

A

Transfer RNA (tRNA)

24
Q

RNA is always _____ stranded

A

single

25
Q

Directs amino sequence of proteins

A

Messenger RNA(mRNA)-

26
Q

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

A

Ribosomal RNA(rRNA)

27
Q

Pocesses intitial mRNA to its mature form in eukaryotes.

A

Small Nuclear RNA(snRNA)

28
Q

Affects gene expression; used by scientists to knock out gene being studied.

A

Small Inefering RNA(siRNA)

29
Q

Affects gene expressions; important in growth and development

A

Micro RNA (miRNA)

30
Q

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

A
  • Exon
30
Q

catalyze cleavage of part of their own sequences in mRNA and tRNA

A

Ribozymes (catalytic RNA)

31
Q

: a section of DNA or mRNA that does not code for a protein.

A

Intron

31
Q

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

A

Gene:

32
Q

In bacteria the gene is

A

continuous

32
Q

. In higher organisms the gene is

A

discontinuous.

33
Q

. DNA double helix unwinds at a specific point called an

A

origin of replication

34
Q

______chains are synthesized in both directions from the origin of replication

A
  • Polynucleotide
35
Q

At each origin of replication, there are

A

two replication forks

36
Q

At each origin of replication, there are two replication forks, points at which new _______ strands are formed.

A

polynucleotide

37
Q
  • DNA is synthesized from its
A

5’ > 3’ end (from the 3’ -> 5’ direction of the template).

38
Q
  • The leading strand is synthesized continuously in the
A

5’ ->

38
Q

The lagging strand is synthesized semidiscontinuously as a series of

A

Okazaki fragments

39
Q

Okazaki fragments of the lagging strand are joined by the

A

enzyme DNA ligase.

39
Q

___-direction toward the replication fork.

A

3

39
Q

Unwinds the DNA double helix/ unzips enzyme

A

Helicase-

40
Q

During replication, the very condensed superstructure of chromosomes is opened by a

A

signal transduction mechanism

40
Q

(also called gyrases) facilitate the relaxation of supercoiled DNA by introducing either single strand or double strand breaks in the DNA.

A

Tropoisomerases

40
Q
  • are assemblies of “enzyme factories”.
A

Replisomes

40
Q

Replication is ______

A

semiconservative

40
Q

Replication is semiconservative

A

each daughter strand contains one template strand and one newly synthesized strand

40
Q

Joins assembled nucleotides

A

DNA Polymerase

41
Q

Threads leading strand

A

Clamp Proteins-

41
Q

removes a positive charge and thus weakens the DNA-histone interactions.

A

Acetylation

41
Q

Synthesizes primers

A

Primase

42
Q

Joins Okazaki fragments in lagging strand

A

Ligase

43
Q

Replication of DNA starts with unwinding of the

A

double helix.

43
Q

signal transduction mechanism.
* One step of this mechanism involves

A

acetylation and deacetylation of key lysine residues

44
Q

Unwinding proteins called _______attach themselves to one DNA strand and cause separation of the double helix.

A

helicases

45
Q

are placed at about every 50 nucleotides in the lagging strand synthesis.

A

Primases

45
Q

are enzymes that catalyze the synthesis of primers

A
  • Primases
46
Q

one of the most common repair mechanisms.

A

Base excision repair (BER)

46
Q

An ______ liberates the sugar-phosphate unit of the damaged site

A

exonuclease

46
Q

are key enzymes in replication.

A
  • DNA polymerases
47
Q

seals the backbone to complete the repair

A

DNA ligase

47
Q

an _______ catalyzes the hydrolysis of the backbone

A

endonuclease

47
Q

It catalyzes the hydrolysis of the -N-glycosidic bond between the incorrect base and its deoxyribose.

A

DNA glycosylase

48
Q

inserts the correct nucleotide

A
  • DNA polymerase
49
Q

removes and repairs up to 24-32 units by a similar mechanism involving a number of repair enzymes

A

NER (nucleotide excision repair

50
Q

a genetically identical population.

A

Clone

51
Q

a process whereby DNA is amplified by inserting it into a host and having the host replicate it along with the host’s own DNA.

A
  • Cloning
52
Q

an automated technique for amplifying DNA using a heat-stable DNA polymerase from a thermophilic bacterium.

A

Polymerase chain reaction (PCR)