unit 9 Flashcards

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1
Q

What is the role of DNA in heredity?

A

-Storing genetic information
-Copying genetic information
-Transmitting the genetic information

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2
Q

What are nucleotides made up of?

A

-5-carbon sugar called deoxyribose
-Phosphate group
-Nitrogenous base

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3
Q

What are the 4 nitrogenous bases in DNA?

A

Thymine, Adenine, Cytosine, Guanine

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4
Q

What is the macromolecule in DNA?

A

Nucleic acid

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5
Q

What is the polymer in DNA?

A

DNA

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6
Q

What is the monomer in DNA?

A

Nucleotide

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7
Q

What direction do the strands in DNA run?

A

In opposite directions, they are antiparallel

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8
Q

What are the nucleotides held together by?

A

Covalent bonds in the backbone

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9
Q

What are the two strands of DNA held together by?

A

Hydrogen bonds between the nitrogenous bases

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10
Q

What are the base pairings?

A

A and T = 2 hydrogen bonds
G and C = 3 hydrogen bonds

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11
Q

Which bonds are the strongest?

A

Covalent bonds

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12
Q

What is the purpose of DNA replication?

A

New copy of DNA for every cell

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13
Q

What does DNA being semiconservative mean?

A

1 parent strand and 1 new strand

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14
Q

What is helicase?

A

The “unzipper”; breaks hydrogen bonds between strands

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15
Q

What is primase?

A

The “initializer”; makes RNA primer

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16
Q

What is polymerse?

A

The “builder”; adds nucleotides to the new strand 5’ and 3’

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17
Q

What is ligase?

A

The “gluer”; create covalent bonds between nucleotides to connect fragments

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18
Q

What are the differences between DNA and RNA?

A

DNA: Deoxyribose sugar, 2 strand, A = T G = C, stores
RNA: Ribose sugar, 1 strand, A = U G = C, transfers

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19
Q

What is the role of DNA?

A

Stores information and genetic material

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20
Q

What are proteins made of?

A

Monomer- Amino acids

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21
Q

What is the role of proteins?

A

Muscles, transport, stores, enzymes, structural

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22
Q

What do the genes in DNA contain?

A

Information to make proteins

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23
Q

What is transcription?

A

Where the cell makes mRNA copies of genes that are needed
Occurs in the nucleus of eukaryotes

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24
Q

What is translation?

A

Where the mRNA is read by the ribosomes to make proteins
Occurs in the cytosol

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25
Q

What is a gene?

A

Unit of DNA that carries information to make a proteins

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26
Q

What is mRNA?

A

Messenger RNA, it carries information from a gene in DNA

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27
Q

What is RNAP

A

RNA polymerase, the enzyme that reads DNA to make mRNA (5’-3’)

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28
Q

What is the first step of transcription?

A

RNA polymerase binds to the template strand of DNA at the beginning of a gene called the promoter

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29
Q

What is the second step of transcription?

A

RNA polymerase moves along the gene unwinding the DNA and creating a complementary strand of RNA stopping when it reaches the terminator. Using the RNA base pairing rules

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30
Q

What is the RNA base pairing rules?

A

G-C and A-U

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31
Q

What is the initial mRNA that is produced called?

A

The primary transcript

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32
Q

How does mRNA become mature?

A

It must go through processing

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33
Q

What are exons?

A

Coding regions (expressed)

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34
Q

What are introns?

A

Non-coding regions (interrupting)
Must be removed before primary transcript is mature and can leave nucleus

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35
Q

What is the roles of a ribosome in translation?

A

It binds mRNA and tRNA to link amino acids together

36
Q

RIbosome structure:

A

Contains 2 subunits one small and one large
Made of proteins and RNA (rRNA)

37
Q

What is tRNA?

A

Transfer RNA, a type of RNA that matches amino acids to specific sequences of mRNA

38
Q

What is a codon?

A

A group of 3 mRNA/DNA that encode a single amino acid

39
Q

What is the link between mRNA and proteins

A

tRNA

40
Q

What is the start codon?

A

ATG/AUG

41
Q

What are the stop codons?

A

UAA, UGA, UAG

42
Q

What is a mutation?

A

A change in the DNA sequence

43
Q

What are the three types of mutations?

A

Insertion: adding one or more nucleotides
Deletion: removing one or more nucleotides
Substitution: changing a single nucleotide for another
Point: affects only one nucleotide

44
Q

What is a silent mutation?

A

The nucleotide change still encodes the same amino acid

45
Q

What is a missense mutation?

A

Replaces the original amino acid with a different amino acid

46
Q

What is a nonsense mutation?

A

Replaces the original amino acid with a stop codon

47
Q

What is frame shift?

A

A mutation caused by the insertion or deletion of a number of nucleotides that is not divisible by 3 disrupting the reading frame, group of codons

48
Q

What is a virus?

A

A non-cellular infectious agent that contains genetic material

49
Q

What characteristics do viruses have?

A

Reproduce with host, sense + response, evolve, growth + development with host, order

50
Q

How is a viral infection caused?

A

Viruses infect host cells by injecting their DNA and they take over the hosts protein synthesis enzymes to make new viruses

51
Q

What is the lytic cycle?

A

When the virus injects its DNA into the host cell and it takes over the function of the cell to make more viruses

52
Q

What is the lysogenic cycle?

A

The viral DNA is injected and it finds its way into the host genome

53
Q

What is a retrovirus?

A

A virus with RNA

54
Q

What can gen regulation do?

A

Change the expression of a gene by turning the gene on or off, down or up

55
Q

What do genes usually have?

A

Regulatory regions ‘upstream’ of the coding region (the part of the gene that gets translated)

56
Q

What are activators?

A

Proteins that increase gene expression

57
Q

What are repressors?

A

Proteins that increase gene expression

58
Q

What are operons?

A

Multiple genes controlled by one promoter and operator (regulatory region)

59
Q

What do operons allow?

A

Many genes to be regulated in the same way

60
Q

What happens when there is an absence of lactose?

A

The repressor protein binds to the operator preventing RNAP from binding to the promoter to begin transcription

61
Q

What happens when there is a presence of lactose?

A

The repressor protein binds to lactose (inducer) cause the repressor to become inactive. Since the repressor can no longer bind to the operator, RNAP can begin transcription

62
Q

What is a lac operon?

A

An inducible operon

63
Q

What is a trp operon?

A

A repressible operon

64
Q

Do eukaryotes have operons?

A

No

65
Q

What are eukaryotic genes regulated by?

A

Proteins called transcription factors

66
Q

What do transcription factors do?

A

They are recruited by enhancers and interact with the promoter to help RNAP bind

67
Q

What happens when DNA is super condensed?

A

The DNA is less accessible to RNAP. More packing = less transcription

68
Q

More methylation of histones =

A

more compact + less transcription

69
Q

More acetylation histones =

A

Less compact

70
Q

What is alternative RNA splicing?

A

When a single DNA gene can be transcribed into 2 or more alternative mRNA forms

71
Q

What does alternative RNA splicing lead to?

A

Leads to multiple proteins that can be made during different conditions

72
Q

What is micro-RNA (miRNA)?

A

Very short RNA sequences that bind to complementary mRNA

73
Q

What happens when miRNA binds to mRNA?

A

miRNA can stop the translation process of the mRNA strand

74
Q

What is mRNA degradation?

A

mRNA that live longer can produce more proteins and it increase the length of the 3’ tail = more stable mRNA

75
Q

What is initiation of translation?

A

Inhibitory proteins can stop the ribosome from translating specific mRNAs

76
Q

What is protein processing?

A

-Some proteins are only active after ____ by a protease. Insulin
-All proteins eventually get degraded. Protein can be tagged for break down by ubiquitin

77
Q

What is reception?

A

Signal molecule (ligand) binds to a receptor in the membrane
-The ligand is specific to the receptor just like and enzyme and substrate

78
Q

What is transduction?

A

The receptor passes the message to relay proteins inside the cell. Those proteins pass the message to other proteins

79
Q

What is response?

A

A gene is turned on or off by regulatory protein

80
Q

What leads to fight of flight response?

A

Epinephrine

81
Q

How does growth factors lead to cancer?

A

If a growth factor becomes hyperactive it could lead to uncontrolled cell growth

82
Q

What are oncogenes?

A

Genes that have developed a mutation that leads to cancer

83
Q

What are tumor suppressor genes?

A

Genes that normally suppress cell division

84
Q

Pronto

A

Oncogenes normally cause the cell to go through checkpoints in the cell cycle

85
Q

Tumor suppressor regulation

A

Decrease expression of tumor suppressors can lead to cancer

86
Q

What do tumor suppressors do?

A

Stop the cell at checkpoints in the cell cycle

87
Q

What are the causes of cancer?

A

Inherited
Viruses
Carcinogen: Cancer causing agents found in the environment