Genetics- Test 1

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What is one of biology's unifying principles

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1

What is one of biology's unifying principles

All organisms use genetic systems that have a number of features in common

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2

What is a genome

A complete set of genetic instructions for any organism

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3

What makes a good genetic model?

  • Short generation line

  • Large but manageable number of progeny

  • Adaptability to laboratory environment

  • Ability to be housed and propagated inexpensively

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4

What are the three chemical composition and structure of DNA and RNA

  1. Pentose Sugar (anchor)

  2. Nitrogenous Base (data)

  3. Phosphate Group (linker)

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5

What pentose sugar does DNA and RNA have

DNA - deoxyribose RNA - ribose

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6

What nitrogenous bases do DNA and RNA use

DNA:

  • Thymine

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7

RNA:

  • Uracil

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8

What is the joining of the anchor and data

Base linked to sugar by 1' carbon of pentose sugar

  • these are nucleotides

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9

What is the linker

A phosphate group attached to the 5' Carbon

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10

Covalent bonds between a phosphate group of one nucleotide and the 3' carbon of the next nucleotides sugar

Phosphodiester bonds

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11

A --> T has how many H bonds

2

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12

C --> G has how many H bonds

3

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13

Watson and Crick investigated the structure of DNA not by collecting new data, but by ___________________________________ about the chemistry of DNA to construct molecular models

using all available information

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14

DNA is a ______ helix

Double

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15

The strands of DNA are

Antiparallel

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16

_______ form between complementary base pairs

Hydrogen bonds

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17

A single set of genes

1C value

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18

T/F Haploid means DNA = 1C

True

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19

N is used to represent what?

The number of chromosome molecules in a cell

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20

T/F Most cells are 2N, 1C Haploid

True

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21

DNA is ______ for compaction

Supercoiled

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22

What does supercoiling rely on

Topoisomerases

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23

DNA with a protein "scaffold"

Chromatin

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24

How many types of histones are there

5

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25

T/F Histones have a net positive charge, thus bind to positive charged DNA

False; bind to negatively charged DNA

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26

____ is a linker between nucleosomes

H1

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27

Stabilizes DNA to the histone so it does not slide off

H1

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28

The ______ is the fundamental repeating unit of chromatin

nucleosome

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29

Diploid eukaryotic cells have how many sets of chromosomes

2

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30

Laying the chromosomes out in a picture is known as a

Karyotype

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31

What are two types of chromatin

  1. Euchromatin

  2. Heterochromatin

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32

This type of chromatin stains lightly and holds "active" genes

Euchromatin

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33

This type of chromatin stains darkly and holds genetically inactive genes

Heterochromatin

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34

What are the two types of Heterochromatin

  1. Constitutive heterochromatin

  2. Facultative heterochromatin

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35

Involved in maintaining chromosome structure and includes centromeres and telomeres

Constitutive heterochromatin

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36

Has the potential to become condensed

Facultative heterochromatin

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37

___________ are used by the cell during cell division to make sure that each daughter cell gets a copy of each chromosome

Centromeres

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38

Where are telomeres located?

The ends of the chromosomes

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39

What is located at the ends of chromosomes that help to protect the ends of the chromosomes from being degraded

Telomere

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40

Adds new copies of the repeat so that the chromosome isn't destroyed by the loss of material after each round of synthesis

Telomerase

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41

Hundreds to thousands of copies per cell

Circular genome

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42

Replicative segregation can lead to both _______ and _________ cells

heteroplasmic and homoplasmic

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43

T/F Each chromosome consists of linear, unbroken, double stranded DNA molecule (one or two, depending on mitosis/meiosis state)

True

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44

DNA replication occurs by a __________________ mechanism

semiconservative

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45

One double helix is unchanged by the process, the other is completely new

Conservative

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46

Each strand is a mix of old and new DNA

Dispersive

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47

One strand of double helix is conserved, the other is new

Semi-conservative

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48

____________ catalyzes the formation of phosphodiester bonds

DNA polymerase

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49

Recall that replication is always

5' --> 3'

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50

DNA synthesis is _______ on one template strand of DNA and ____________ on the other

continuous; discontinuous

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51

What are the 5 key elements of each replication fork

  1. Helicase to unwind the DNA

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52
  1. SSBP to protect ssDNA

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53
  1. Gyrase to remove strain ahead of fork

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  1. Primase to synthesize RNA primer

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  1. DNA polymerase

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56

DNA replication in Eukaryotes is initiated by ___________

RNA primers

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57

DNA replication in eukaryotes is ______

semiconservative

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58

What are the steps of packaging newly replicated DNA

  1. histones must first disassemble to allow DNA synthesis

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59
  1. synthesis of new histones is coordinated with DNA synthesis

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60
  1. Then must reassemble on two new chromosomes

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61

Main polymerases have a 3' --> 5' __________ activity

exonuclease

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62

DNA replication is _______

semi-conservative

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63

T/F A small number of enzymes are involved in DNA replication

False; Large

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64

G1 contains the ________. Once the cell passes this point, then it must enter S phase

'checkpoint'

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65

What happens during the S phase

DNA untwists and replicates

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66

What are the 5 phases of Cell life-cycle

  1. G1

  2. G0

  3. S

  4. G2

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67

Formation of two cells from one cell

Mitosis

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68

How many stages are in mitosis and what are they

5 stages:

  1. Interphase

  2. Prophase

  3. Metaphase

  4. Anaphase

  5. Telophase

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69

What happens during prophase of mitosis

  • Chromosomes condense

  • Two sister chromatids become detectable

  • Mitotic spindle assembles outside the nucleus

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70

What happens in metaphase?

  • Chromosomes arrange on metaphase plate

  • Centrosomes at opposite poles

  • Microtubules from centrosomes to kinetochore

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71

What happens during anaphase?

  • Sister chromatids separate

  • Chromosomes move toward opposite poles

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72

What happens during telophase?

  • Sister chromatids arrive at opposite poles (now called chromosomes)

  • Nuclear membranes form

  • Chromosomes relax and lengthen

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73

T/F Meiosis includes four cell divisions

False

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74

Chromosomes cross-over (recombination) during what stage of Meiosis

Prophase I

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75

Random distribution of chromosomes in meiosis produces ________

genetic variation

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76

What is the Central dogma?

DNA-transcription-RNA-translation-protein

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77

What is the first step of the central dogma

Transfer of genetic material from DNA to mRNA (get the info out of storage)

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78

Describe mRNA

  • Has instructions to make a protein

  • Each protein has a unique mRNA

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79

Describe tRNA

Translates instructions into protein "language"

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80

Describe rRNA

Machine that "builds" a protein

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81

What are the key components needed for transcription

  1. A DNA template

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82
  1. The raw materials (ribonucleotide triphosphates) needed to build a new RNA molecule

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83
  1. The transcription apparatus, consisting of the proteins necessary for the catalyzing the synthesis of RNA

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84

What are 3 main types of RNA polymerases

  1. RNA Pol I

  2. RNA Pol II

  3. RNA Pol III

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85

What does RNA Pol I do

Transcribes ribosomal RNA (rRNA)

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86

What does RNA Pol II do

Transcribes pre-messenger mRNA

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87

What does RNA Pol III do

Transcribes tRNA (and other small RNAs)

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88

Describe what a promotor is

Sequence that transcription machinery recognizes and binds (generally not transcribed)

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89

Describe Coding region

The sequence that is copied (transcribed) from DNA to RNA

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90

Define terminator

Specific sequences that indicate transcription should stop (generally is transcribed)

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91

Describe a core promotor

  • Generally required for any transcription

  • Transcription factors and regulatory factors can bind here (control expression timing)

  • TATA box

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92

Describe a regulatory promoter

  • Variety of consensus sequences

  • Transcription factors and regulatory factors can bind here

  • Affect the rate of transcription

  • Directly or indirectly make contact with basal transcription machinery

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93

Distal locations can also enhance transcription

Enhancers

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94

What is initiation of protein coding genes

If the promotor (core and regulatory) and enhancers "say so", a protein-coding gene is transcribed

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95

Keep adding nucleotides

Elongation

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96

For RNA Pol II there is no specific termination sequence

Termination

  • can continue for 100s - 1000s bp

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97

What is a gene

Gene is the fundamental unit of heredity

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98

Most eukaryote organisms have ________

intons

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99

What is an exon

Region of DNA that codes for a protein

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100

T/F In eukaryotes, intron size and number is related to organism complexity

True

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