Cell Biology Exam Chapters 3-6

Front 1

Gene

Back 1

discrete, functional DNA;
when expressed, yields a functional products

Front 2

Open reading frame

Back 2

long stretch of nucleotides that can encode polypeptide due to absence of stop codons

Front 3

Chromosome

Back 3

discrete, linear molecule of double-stranded DNA

Front 4

Centromere

Back 4

site that connects sister chromatids

Front 5

Kinetochore

Back 5

attachment site of spindle to chromosome

Front 6

Teleomere

Back 6

nucleotide repeat at end of linear chromosome

Front 7

Telomer

Back 7

resists nuclease digestion;
synthesized by Telomerase

Front 8

Karyotype

Back 8

photograph of chromosomes from a single organism

Front 9

What is the function of histone proteins?

Back 9

Histone proteins package eukaryotic nuclear DNA.

Front 10

Chromatin

Back 10

Nuclear DNA+Associated proteins

Front 11

Heterochromatin

Back 11

condensed, transcriptionally inactive chromatin

Front 12

Constituitive heterochromatin

Back 12

DNA is never transcribed

Front 13

Facultative heterochromatin

Back 13

DNA is not transcribed in that cell type, but is transcribed in other cell types.

Front 14

Euchromatin

Back 14

decondensed, transcriptionally active interphase chromatin

Front 15

Nucleosome core particle

Back 15

146 b.p. DNA wraps 1.75 times around histone octomer

Front 16

Chromatosome

Back 16

166 b.p. DNA locked in place around histone octomer by histone H1

Front 17

What do chromatosomes pack to form?

Back 17

Chromatin fibers

Front 18

Central Dogma of Molecular Biology

Back 18

DNA → RNA → Protein via replication, transcription, and translation, respectively

Front 19

Mutation

Back 19

change in DNA sequence

Front 20

What does it mean to say that DNA replication is Semiconservative?

Back 20

Each parental strand serves as template for synthesis of a new complementary strand.

Front 21

In what direction does DNA polymerase synthesis DNA?

Back 21

5' to 3'

Front 22

DNA Polymerase

Back 22

template directed synthesis of complementary DNA strand by addition of nucleotides

Front 23

Name the five DNA polymerases and tell the function of each.

Back 23

α-replicative
β-repair
γ-organelle
δ-replicative
Δ-unclear

Front 24

Helicase

Back 24

unwinds DNA

Front 25

Primase

Back 25

synthesizes RNA primers

Front 26

Topoisomerase

Back 26

relives torsenal strain in DNA double helix

Front 27

Topoiomerase type I

Back 27

breaks phosphodiester bond on one DNA strand

Front 28

Topoiomerase type II

Back 28

breaks phosphodiester bond on both DNA strands

Front 29

Ligase

Back 29

seals nicks (breaks) in phosphodiester backbone

Front 30

RNase H

Back 30

digests RNA molecule n DNA:RNA hybrid

Front 31

Single Stranded DNA Binding Protein

Back 31

binds and protects single stranded DNA

Front 32

Exonuclease

Back 32

digests DNA

Front 33

Exonuclease 5' to 3'

Back 33

digests DNA in fron of synthesis

Front 34

Exonuclease 3' to 5'

Back 34

removes newly synthesized nucleotide (especially if incorrectly incorporated)
(proofreading)

Front 35

Reverse transcriptase

Back 35

RNA molecule serves as template for DNA synthesis

Front 36

Leading strand

Back 36

continous synthesis

Front 37

Lagging strand

Back 37

discontiuous synthesis (Okazaki fragments)

Front 38

What happens if the incorrefct base is incorporated?

Back 38

creates mutation which is the fuel for evolution

Front 39

Origin

Back 39

discrete site on chromsome where replication begins

Front 40

Trasciption

Back 40

occurs in nucleus;
catalzed by RNA polymerase

Front 41

In what direction is RNA synthesized?

Back 41

5' to 3'

Front 42

RNA Polymerase I

Back 42

functions in the nucleolus;
synthesizes 45S pre rRNA (18S, 5.8S, 28S rRNA)

Front 43

RNA Polymerase II

Back 43

functions in the nucleus;
pre-mRNA

Front 44

Monocistronic

Back 44

endcode one polypeptide per transcript

Front 45

Polycistronic

Back 45

encode several polypeptides per transcript

Front 46

Chromatosome

Back 46

166 b.p. DNA locked in place around histone octomer by histone H1

Front 47

What do chromatosomes pack to form?

Back 47

Chromatin fibers

Front 48

Central Dogma of Molecular Biology

Back 48

DNA → RNA → Protein via replication, transcription, and translation, respectively

Front 49

Mutation

Back 49

change in DNA sequence

Front 50

What does it mean to say that DNA replication is Semiconservative?

Back 50

Each parental strand serves as template for synthesis of a new complementary strand.

Front 51

In what direction does DNA polymerase synthesis DNA?

Back 51

5' to 3'

Front 52

DNA Polymerase

Back 52

template directed synthesis of complementary DNA strand by addition of nucleotides

Front 53

Name the five DNA polymerases and tell the function of each.

Back 53

α-replicative
β-repair
γ-organelle
δ-replicative
Δ-unclear

Front 54

Helicase

Back 54

unwinds DNA

Front 55

Primase

Back 55

synthesizes RNA primers

Front 56

Topoisomerase

Back 56

relives torsenal strain in DNA double helix

Front 57

Topoiomerase type I

Back 57

breaks phosphodiester bond on one DNA strand

Front 58

Topoiomerase type II

Back 58

breaks phosphodiester bond on both DNA strands

Front 59

Ligase

Back 59

seals nicks (breaks) in phosphodiester backbone

Front 60

RNase H

Back 60

digests RNA molecule n DNA:RNA hybrid

Front 61

Single Stranded DNA Binding Protein

Back 61

binds and protects single stranded DNA

Front 62

Telomerase

Back 62

synthesizes telomeres

Front 63

Exon Nuclease

Back 63

digests DNA

Front 64

Exon Nuclease 5' to 3'

Back 64

digests DNA in front of synthesis

Front 65

Exon Nuclease 3' to 5'

Back 65

removes newly synthesized nucleotide (especially if incorrectly incorporated)

Front 66

Reverse transcriptase

Back 66

RNA molecule serves as template for DNA synthesis

Front 67

Leading strand

Back 67

continous sythesis

Front 68

Lagging strand

Back 68

discontinous sythesis (Okazaki fragments)

Front 69

Origin

Back 69

discrete site on chromosome where replication begins

Front 70

Transcription

Back 70

occurs in nucleus;
catalzyed by RNA polymerase

Front 71

In what direction is RNA sythesized?

Back 71

5' to 3'

Front 72

RNA Polymerase I

Back 72

functions in nucleolus;
synthesizes 45S preRNA (18S, 5.8S,and 28S rRNA)

Front 73

RNA Polymerase II

Back 73

function in nucleus
synthesizes pre-mRNA

Front 74

Monocistronic

Back 74

encodes one polypeptide per transcript

Front 75

Polycistronic

Back 75

encodes several polypeptides per transcript

Front 76

Capping

Back 76

addition of methylguanosine to 5' end of transcript;
reverse 5' to 5' linkage of methylguanosine

Front 77

Polyadenylation

Back 77

addition of chain of AMP to 3' end of transcript

Front 78

Splicing

Back 78

removal of introns

Front 79

Intron

Back 79

noncoding region

Front 80

Exon

Back 80

coding region

Front 81

RNA Polymerase III

Back 81

function in nucleus;
5.0 rRNA;
sythesizes pre tRNA

Front 82

Pre tRNA

Back 82

single strand of 70-80 ribonucleotides;
folds into a cloverleaf structure

Front 83

Describe how tRNA is synthesized from pre tRNA.

Back 83

5' end cleaved by RNAse P ribozyme;
3' end cleaved by RNAse;
CCA added to 3' end;
base modified;
anticodon used

Front 84

CCA

Back 84

attachment site for amino acid

Front 85

Translation

Back 85

protein sythesis in cytosol

Front 86

Ribosome

Back 86

rRNA + r proteins

Front 87

mRNA

Back 87

homologous to DNA sequence;
contains codon (3 nucleotides)

Front 88

tRNA

Back 88

adapter between amino aicd and mRNA;
amino attachment site CCA 3';
anticodon interacts with codon of mRNA

Front 89

Where are ribosomal subunits assembled?

Back 89

in the nucleus

Front 90

Where are ribosomal subunits transported to?

Back 90

They are transported through nuclear pore into the cytoplasm.

Front 91

Where are free ribosomes found?

Back 91

in the cytoplasm

Front 92

Where are bound ribosomes found?

Back 92

attached to the ER