Biochemistry Block 2: Structure Of Nucleic Acids

Front 1

_____ isolated DNA and termed it nuclein

Back 1

Frederic Meischer

Front 2

______ discovered order of three major components of a single nucleotide and proposed "polynucleotide" model

Back 2

Phoebe Levene

Front 3

_____ found that DNA carries genetic information

Back 3

Oswald Avery

Front 4

_____ reported that adenine equals thymine and guanine equals cytosine in DNA

Back 4

Erwin Chargaff

Front 5

_____ proposed double helix structure of DNA based on X-ray crystals

Back 5

James Watson and Francis Crick

Front 6

The ____ is the organism's hereditary information

Back 6

genome

Front 7

In organizations of genomes, ______ have no special subcellular structure for DNA and its DNA-protein complex is located in the _____

Back 7

-prokaryotes
-nucleoid

Front 8

____ contain DNA or RNA. They lack complete system for replication, transcription, and translation

Back 8

viruses

Front 9

_____ are small circular DNA molecules that can replicate autonomously - outside of host genome
It is also often used in _____ as a tool for transfer of foreign genes from one organism to another

Back 9

-plamids
-genetic engineering

Front 10

If chromatin diffuses, it is _____
If chromatin is compact, it is _____

Back 10

-euchromatin (active)
-heterochromatic (inactive)

Front 11

DNA replicates to form sister ____ and these condense to form visible _____

Back 11

-chromatides
-chromosomes

Front 12

The human diploid genome consists of _____ chromosomes

Back 12

46

Front 13

Nucleotides are joined by ____

Back 13

inorganic phosphates

Front 14

DNA sequence is written in _____ direction

Back 14

5' to 3'

Front 15

In DNA, two polynucleotide chains are connected by _____
Purines from one strand form bonds with (purines/pyrimidines) of the other strand

Back 15

-Hydrogen bonds
-pyrimidines
*purines = pyrimidines

Front 16

_____ form of DNA is a wider form of the B form (normal) of DNA
It is normally found in what types of DNA?

Back 16

-A form

-dehydrated samples of DNA
-DNA-RNA hybrids
-enzyme-DNA complexes

Front 17

Z form of DNA is linked to what?
These may be involved in:

Back 17

-initiation of transcription
-extensive methylation

-regulation of transcription

Front 18

The major and minor grooves of DNA are used for binding of:

Back 18

-regulatory proteins
-antibiotics
-anticancer drugs

Front 19

Strands of DNA can be separated by:

Back 19

alkali and heat

Front 20

____ are used to break RNA from DNA
How?

Back 20

-Alkali
-Alkali brakes phosphodiester bonds of RNA, but not DNA

Front 21

____ alone can convert dsDNA to ssDNA

Back 21

Heat

Front 22

Tm is:
It depends on:

Back 22

-temperature where 50% of DNA is separated
-GC content (more GC = higher temp)

Front 23

Reducing temperature slowly (can/can not) renature or hybridize and form dsDNA

Back 23

can

Front 24

Fluorescent in situ hybridization (FISH) can be used to find specific sequences in ____
Gel southern blot can can find specific sequences in ____ while norther blot finds sequences in _____

Back 24

-Genome
-DNA
-RNA

Front 25

____ is used to amplify specific DNA sequences

Back 25

polymerase chain reaction (PCR)

Front 26

In ____, DNA is supercoiled and attached to RNA-protein forming _____

Back 26

-E. coli
-nucleoid

Front 27

Compaction of eukaryotic DNA is achieved through its binding to ____ which are basic proteins
The five major types of these are:

Back 27

-histones
-H2A
-H2B
-H3
-H4
-H1

Front 28

Complex of DNA and proteins are called ____

Back 28

chromatin

Front 29

Nucleosome core is formed by ____
Linker DNA is complexed with ____

Back 29

-8 histone molecules
-histone H1

Front 30

Nucleosomes form a tubular coil called a ____

Back 30

-solenoid (30nm fiber)

Front 31

Enzymes and regulators involved in metabolism of nucleic acids are found _____

Back 31

bound to DNA

Front 32

Each chromosome in the cell nucleus occupies _____ and suggest a specific ____ within the nucleus

Back 32

-specific territories
-3D organization

Front 33

Histones are packed and regulate gene transcription. ______ activity reduces the negative charge of and loosens the histones and creates open ____

Back 33

-acetyltransferase (HAT) activity
-chromatin

Front 34

Methylation of amino acid on histones can lead to:

Back 34

-activation or silencing of transcription

Front 35

____ is the basic unit of hereditary in all living organisms

Back 35

Gene

Front 36

_____ is a position of a gene on a chromosome

Back 36

genetic locus

Front 37

Only _____% of are exons (or protein-coding)

Back 37

~1.5%

Front 38

_____ is used to determine the (diploid) number of chromosomes

Back 38

-karyotyping
-also used in sex and abnormalities

Front 39

_____ results from a single X chromosome in females
They may have what symptoms?

Back 39

-Turner syndrome

-infertile
-cardiovascular and kidney problems
-osteoperosis

Front 40

______ most common male chromosomal disease, otherwise known as XXY
They may also have a high incidence of:

Back 40

-Klinefelter syndrome

-germ cell tumor and male breast cancer

Front 41

_____ is caused by trisomy of chromosome 18
What may kind of abnormalities may you see?

Back 41

-Edwards syndrome

-Intestines protruding outside the body and developmental delays

Front 42

_____ is caused by trisomy of chromosome 21

Back 42

Down syndrome

Front 43

______ is caused by trisomy of chromosome 13
What may you see in patients with this disease?

Back 43

Patau syndrome
-Microcephaly, heart and kidney defects

Front 44

What are the four differences between DNA and RNA?

Back 44

RNA is:
-smaller
-single stranded
-ribose not deoxyribose
-U instead of T

Front 45

_____ cleaves off an extra sequence of RNA on tRNA molecules

Back 45

RNAse P

Front 46

____ activity of ribosome is necessary to form peptide bonds during protein synthesis

Back 46

peptidyl transferase

Front 47

_____ comprises of about 5% of RNA and is the most heterogeneous type of RNA

Back 47

mRNA

Front 48

On mRNA a cap is found on the _____ end and is required for _____ of transcription
The _____ region can be translated
The poly-A tail on the _____ end (stabilize/destabilize) mRNA after transcription

Back 48

-5'
-initiation
-coding region
-3'
-stabilize

Front 49

____ is the most abundant RNA

Back 49

rRNA

Front 50

Synthesis of rRNA and assembly of ribosomes occur in _____

Back 50

the nucleolus

Front 51

Bacterial ribosome is similar to ______ ribosomes

Back 51

mitochondrial

Front 52

What are the differences between prokaryotic and eukaryotic ribosomes?

Back 52

-Prokaryotes contain three types (eukaryotic has 4 types) of rRNA and less proteins

Front 53

____ is small and is the first nucleic acid to be sequenced
The primary structures of these differs and they all resemble a ____

Back 53

-tRNA
-cloverleaf

Front 54

Cells contain at least ____ types of tRNA, one for each ____

Back 54

-20
-amino acid

Front 55

Amino acids (may/may not) have more than one codon

Back 55

may

Front 56

How and what are the functions of tRNA?

Back 56

-AA attaches to 3' end
-carries AA to ribosomes
-Anticodon of tRNA binds to codon on mRNA
-provides proofreading mechanism during translation

Front 57

____ are necessary for replication of DNA

Back 57

primer RNAs

Front 58

Small nuclear _____ are involved in splicing

Back 58

snRNA

Front 59

____ is involved in inactivating one of the X chromosomes in vertibrates

Back 59

Xist (X-inactive specific transcript) RNA

Front 60

_____ are derived from endogenous (inside the cell) genes and repress protein biosynthesis, usually by preventing the ribosome binding to mRNA

Back 60

-micro RNA (miRNA)

Front 61

Synthesis of DNA chain can be blocked by incorporation of ____. Examples of these include:
Replacement of hyroxyl group by ____
Removal of hydroxyl group from ____
Conversion of deoxyribose to another sugar _____

Back 61

-nucleotide analogs

-azido group (AZT)
-deoxyribose (ddl)
-arabinose

**reverse transcriptase has higher affinity for AZT than normal DNA polymerases

Front 62

____ inhibits the synthesis of the thymine nucleotides required for DNA replication by inhibiting _______
This could also be used to treat ____

Back 62

-5-FU
-thymidylate synthase (converts dUMP to dTMP)

-different types of cancers

*dTMP needed for DNA synthesis