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Evolutionary Biology > Introduction and Evolution of HIV > Flashcards

Introduction and Evolution of HIV Flashcards

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1
Q

Understanding the processes of evolution is highly relevant to?

A

human health

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2
Q

It is concerned with explaining and understanding the diversity of living things and their characteristics.

A

Evolutionary biology

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3
Q

It extends and amplifies
the explanation of biological phenomena.

A

Evolutionary biology

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4
Q

Evolutionary biology extends and amplifies
the explanation of biological phenomena complementing?

A

proximate causes and ultimate causes

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5
Q

immediate, mechanical causes

A

proximate causes

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6
Q

their historical causes, especially the action of natural selection

A

ultimate causes

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7
Q

Nothing in Biology Make Sense except in the light of Evolution by

A

Theodosius Dobzhansky (1900-1975)

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8
Q
  • The increase in fitness over time due to natural selection, or adaptation
  • The accumulation of mutations, which alter fitness over time
  • The change in allele frequencies (or the heritable expression of
    those alleles) in a population across generations
  • The progression into more complex forms of life
A

Evolution

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9
Q

Evolution is the increase in fitness over time due to ____ _____ or _____ _____

A

natural selection or adaptation

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10
Q

Evolution is the accumulation of ______, which alter fitness over time

A

mutations

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11
Q

Evolution is the change in ____ ______ in a population across generations

A

allele frequencies

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12
Q

the heritable expression of those allele

A

allele frequencies

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13
Q

Evolution is the progression into more

A

complex forms of life

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14
Q

Evolution is change in ______ of genetically different individuals at each generation

A

proportions

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15
Q

I leads to an average change in characteristics of populations over time

A

change in allele frequencies or the heritable change in the expression of those alleles

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16
Q

change in allele frequencies

A

(genetic composition

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17
Q

heritable change in the expression of those alleles

A

epigenetic inheritance

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18
Q

Evolution acts by removing individuals from the population or by allowing some

A

to leave more offspring

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19
Q

A group of interbreeding
individuals and their offspring (in the case of sexual species)

A

population

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20
Q

The change in allele frequencies (or the heritable expression of those alleles) in a population across
generations.

A

evolution

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21
Q

Even if allele frequencies in a population remain the
same across generations, a population is evolving if it goes out of the _____

A

Hardy-Weinberg Equilibrium

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22
Q

It show follow HW expectations, given the allele frequencies

A

genotype frequencies

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23
Q

How does evolution occur?

A

through 5 major mechanisms: genetic drift, mutation, heritable epigenetic modification, migration, and natural selection

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24
Q

Totally random changes in allele frequency from generation to generation

A

Genetic Drift

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25
Q

Changes in the genetic code, such as error in DNA replication, gene deletions or duplications, etc.

A

Mutation

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26
Q

heritable changes that are not due to changes in DNA sequence itself, but the expression of the DNA, such as changes in DNA methylation and histone modifications, etc.&raquo_space; changes “epi-alleles” not the genetic code (actual alleles

A

Epigenetic inheritance

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27
Q

Alleles moving from one population to another

A

Gene flow (Migration)

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28
Q

When some alleles favored over others due to an increase in fitness (not random); acts on genetic variation in the population

A

Natural Selection

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29
Q

How does evolution occur?

A

Natural Selection

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30
Q

What are the sources of genetic variation?

A
  • mutation
  • epigenetic inheritance
  • genetic drift
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31
Q

It generates genetic variation

A

mutation

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32
Q

It changes expression of genes

A

Epigenetic inheritance

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33
Q

It reduces genetic variation

A

Genetic drift

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34
Q

It acts on genetic or epigenetic variation in a population

A

Natural Selection

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35
Q

Without it, natural selection cannot occur

A

genetic or epigenetic variation

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36
Q

Evolutionary concepts permeate all aspects of biology

A
  • Biotechnology
  • Agriculture
  • Medicine
  • Conservation
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37
Q

Many of our food is a product of intense

A

artificial selection or human-induced evolution

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38
Q

It is the fastest evolving organism on Earth

A

HIV

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39
Q

It infects macrophages and T-cells

A

HIV

40
Q

It is among the deadliest epidemics in human history

A

AIDS

41
Q

WHO estimates in 2019 that _____ have died and ___ have been infected, and ___ people currently living with AIDS

A
  • 32.7 million
  • 75.7 million
  • 38 million
42
Q

What are the body fluids that transmit HIV?

A
  • blood
  • semen(cum)
  • rectal fluids
  • pre-seminal fluid
  • breast milk
  • vaginal fluids
43
Q

Only certain ____ ____ from a person who has HIV can transmit HIV

A

body fluid

44
Q

This fluid must ______ from a needle or syringe for transmission to occur

A
  • come in contact with a mucous membrane or damaged tissue
  • be directly injected into the bloodstream
45
Q

Mucous membranes are found inside the

A
  • rectum
  • vagina
  • penis
  • mouth
46
Q

Mode of transmission HIGH RISK

A
  • sexual intercourse
  • injection drug use
47
Q

Mode of transmision LITTLE NO RISK

A
  • oral sex, biting, spitting
  • food contamination
  • deep, open-mouth kissing
  • touching
  • tattoos, body piercing
  • medical care
48
Q

Likely mode of transmission in year 2002 of Cambodia, Honduras, Russia, Indonesia, and Kenya (1998)

A
  • injection drug use
  • sex work
  • heterosexual sex with a partner at high-risk
  • male-male sex
  • casual heterosexual sex
49
Q

Likely mode of transmission in US (2006), Canada (2005), and UK (2007)

A
  • male-male sex
  • MMS & IDU
  • Injection drug use (IDU)
  • heterosexual sex
50
Q
  • Retrovirus with two single strand RNAgenomes
  • Uses the enzyme reverse transcriptase to replicate RNA → DNA
  • Has an integrase to
    incorporate its genome to the host genome
  • Attacks host immune
    system: infects macrophages and helper Tcells
A

Human Immunodeficiency virus or HIV

51
Q

HIV is a ___ with two single strand RNA genomes

A

Retrovirus

52
Q

HIV uses the enzyme ____ ____ to replicate DNA

A

reverse transcriptase

53
Q

HIV has an ___ to incorporate its genome to the host genome

A

integrase

54
Q

HIV attack ____ and infects ____

A
  • attack host immune cells
  • infects macrophages and helper T cells
55
Q

It capture the virus and present bits of its proteins to naive helper T cells

A

Dendritic cells

56
Q

This cells divide to produce effector helper T cells

A

Naive cells

57
Q

It stimulates B cells displaying the same bots of viral protein to mature into plasma cells, which make antibodies that bind and in some cases inactive the virus

A

Effector helper T cells

58
Q

It also activate killer T cells, which destroy host cells infected with the virus

A

Effector helper T cells

59
Q

It destroy host cells infected with the virus

A

killer T cells

60
Q

Mots of it are are short, but a few become long-lived memory helper T cells

A

effector T cells

61
Q

HIV has the ____ _____ ___ of any virus or organism observed to date

A

fastest mutation rate

62
Q

It evolves more rapidly than humans and more quickly than the ability of humans to produce new drugs

A

HIV

63
Q

These are unlikely to work on all strains of the virus and unlikely to work on a given strain in the long run

A

AIDS vaccines

64
Q

HOW might HIV evolve?

A

Drugs impose selection on HIV —-> transmission rate imposes selection on HIV ——-> host immune system also imposes selection

65
Q

evolution of drug resistance

A

Drugs impose selection on HIV

66
Q

evolution of virulence

A

transmission rate imposes selection on HIV

67
Q

it also imposes selection on HIV

A

host immune system

68
Q

It is a thymidine mimic which stops reverse transcription and impedes viral replication

A

Azidothymidine (AZT)

69
Q

Example of an HIV drug

A

AZT

70
Q

Why does AZT work initially but fail in the long run?

A

fat mutation rate
natural selection

71
Q

Lots of mutations arise, including in the reverse transcriptase gene of HIV—->

A

Fast Mutation rate —–> genetic variation

72
Q

It favors reverse transcriptase enzyme mutant that can recognize AZT and not use it

A

Natural selection

73
Q

an enzyme thatnis
slow, but the virus is now resistant to AZT

A

careful reverse transcriptase enzyme

74
Q

The careful reverse transcriptase enzyme is
slow, but the virus is now resistant to AZT

A

evolutionary tradeoff between fast & sloppy
vs. slow & careful enzyme

75
Q

It favors mutants that are resistant to AZT

A

Natural selection

76
Q

Mutations in the viral reverse transcriptase gene of HIV arises

A

Fast mutation rate

77
Q

Favors reverse transcriptase enzyme that can recognize AZT and not use it

A

Natural Selection

78
Q

These mutations slow down the virus (as it becomes more careful), but makes the virus resistant to AZT

A

tradeoff between speed vs. accuracy of reverse
transcription

79
Q

Why does fast & sloppy are favored?

A

because fast replicating mutants would outgrow the slower

80
Q

What would happen when AZT therapy stops?

A

Back mutations that restore the amino acid sequence to the original state are then favored by selection so that
reverse transcription could speed up again

81
Q

Evolutionary tradeoff between fast viral population growth versus keeping the host alive

A

Need to keep host alive long enough to get passed on to the next host

82
Q

can grow fast and jump to the next host; ok if host dies; the genetic strain that grows faster will win

A

High transmission rate: High virulence

83
Q

More virulent strains would die with the host and get selected out; less virulent strain that does not kill the host will win

A

Low transmission rate; low virulence

84
Q

will select for high virulence

A

High Transmission rate

85
Q

If the virus is likely to move to a new host, the faster growing (and more virulent) strain is likely to overtake
the slower strains and “win”

A

High Transmission rate

86
Q

Kill the host since the chance of jumping to a new host is high

A

High transmission rate

87
Q

It favors the more virulent strain

A

Natural selection

88
Q

Will select for low virulence

A

Low transmission rate

89
Q

If the virus is not likely to move to a new host the slower growing (and less virulent) strain is likely to
“win

A

Low transmission rate

90
Q

since the chances of jumping to a new host is low. If the virus kills the host, it will kill
itself

A

It’s not ok to kill the host

91
Q

will favor the less virulent strain

A

Natural selection

92
Q

How to combat HIV

A
  • must lower transmission rate of HIV so that less fatal strains evolve
  • must understand evolutionary properties of a disease
93
Q

Must understand evolutionary properties of a disease

A
  • evolutionary history
  • mutation rate
  • selective forces
  • evolutionary tradeoffs
94
Q

evolution in response to AZT

A

slow and accurate vs fast and sloppy replication

95
Q

Evolution in response to transmission rate

A

slow growing & less virulent (keep host alive_ vs fast growing & more virulent

Evolutionary Biology (1 decks)

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