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Biology > chapter twenty-one/twenty-two > Flashcards

chapter twenty-one/twenty-two Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

how much of our genome is transcribed into mRNA, tRNA, and rRNA

A

1.5%

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2
Q

intergenic DNA

A

DNA between genes
- some unique, like pseudogenes

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3
Q

pseudogenes

A

former genes that have accumulated mutations and are nonfunctional

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4
Q

what is most DNA?

A

repetitive DNA
- present in multiple copies in the genome

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5
Q

types of repetitive DNA

A
  1. transposable elements and related sequences
  2. other repetitive DNA
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6
Q

transposable elements and related sequences

A

can move from one location to another within genome through recombination process

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7
Q

discovery of transposable elements

A
  • geneticist Barbara McClintock
  • worked with calico corn
  • observed effects of mobile DNA pieces, moved from one site to another in cell’s DNA
  • present in both proks/euks
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8
Q

2 types of transposable elements in eukaryotes

A
  1. transposons
  2. retrotransposons
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9
Q

transposons

A
  • move via DNA intermediate
  • cut/paste - no copy at original site
  • copy/paste - leaves copy at original site
  • requires enzyme transposes encoded by transposon
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10
Q

retrotransposons

A
  • move via RNA intermediate
  • converted back to DNA w/ reverse transcriptase
  • always leaves copy at original site
  • most
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11
Q

Alu-elements

A

transposable element-related DNA in humans/primates
- some transcribed, but function of RNA molecules unknown
- type of SINEs (short interspersed nuclear element)

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12
Q

LINEs

A

long interspersed nuclear elements
- type of retrotransposon
- like L1
- longer than Alu elements, low rate of transposition

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13
Q

what did other repetitive DNA probably arise from?

A

mistakes during DNA replication and recombination

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14
Q

types of other repetitive DNA

A
  • long sequence duplications
  • simple sequence duplications (STRs)
  • multigene families
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15
Q

simple sequences duplications

A

many copies of tandemly-repeated units
- STRs
- common in centromeres and telomeres

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16
Q

STRs

A

short tandem repeats
- 2-5 nucleotide repeating units, repeating thousands of times
- repeat numbers can vary among sites within genome and btw ind

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17
Q

function of simple sequence DNA in centromeres and telomeres

A
  • centromeres - separation of sister chromatids
  • telomeres - protects against degradation, joining to other chromosomes
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18
Q

multigene families

A

collections of identical or very similar genes
- identical: rRNA genes clustered tandemly
- non-identical - globin gene families, dif forms of global expressed at dif times

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19
Q

polyploidy

A

extra sets of chromosomes

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20
Q

duplications and inversions

A

result from mistakes during meiosis
- unequal c-o during prophase I

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21
Q

what happens when gene family members get duplicated

A

some are used, other can accumulate mutations

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22
Q

exon duplication

A

can be duplicated on 1 chromosome and deleted from another

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23
Q

exon shuffling

A

mixing/matching of different exons within gene or between 2 dif genes

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24
Q

multiple transposable elements can facilitate recombination between different _________

A

chromosomes

25
Q

how can transposable elements cause trouble?

A

if they insert within a protein-coding sequence of gene regulatory sequence

26
Q

what does comparing distantly related species help us understand?

A

“ancient evolutionary events”

27
Q

what can be studied in model organisms?

A

highly conserved genes

28
Q

what can genetic differences between closely related species be correlated with?

A

phenotypic differences

29
Q

human genome diversity

A
  • SNPs
  • CNVs
30
Q

SNPs

A

single nucleotide polymorphism
- single base-pair sites where genetics variations found in a least 1% of pop

31
Q

CNVs

A

copy-number variation
- variation in copies of a particular gene or genetic region

32
Q

homeotic genes

A

specify identity of body segments in animal development
- all contain homeobox region

33
Q

homeobox region

A

sequence that codes for homeodomain in the resultant protein
- important for development

34
Q

what organisms are homeobox sequences found in?

A

vertebrates and invertebrates, related sequences in plants, fungi, prokaryotes

35
Q

sometimes small changes in regulatory sequences of certain genes leads to what?

A

changes in body form

36
Q

when was the Origin of Species published?

A

1859

37
Q

The Origin of Species

A

focused attention on great diversity of organisms
- Darwin noted that current species are descendants of ancestral species

38
Q

evolution

A

descent with modification
- where species accumulates differences from ancestors over time

39
Q

Aristotle

A

viewed species as fixed and arranged them on Scala naturae

40
Q

Old Testament

A

species individually designed by God and therefore perfect

41
Q

Carolus Linnaeus

A
  • interpreted organismal adaptations as evidence that Creator had designed each species for specific purpose
  • founder of taxonomy
  • developed binomial format for naming species
42
Q

paleontology

A

study of fossils
- largely developed by French scientist Georges Cuvier

43
Q

catastrophism

A
  • Cuvier
  • each boundary between starts represents a catastrophe
44
Q

what did James Hutton and Charles Lyell claim?

A

that changes in earth’s surface can result from slow continuous actions still operation today

45
Q

Lyell’s principle of uniformitarianism

A

states mechanisms of change are constant over time
- influenced Darwin’s thinking

46
Q

Lamarck’s Hypothesis of Evolution

A

species evolve through use and disuse of body parts and inheritance of acquired characteristics
- unsupported by evidence

47
Q

what did Darwin perceive adaptations to the environment and the origin of new species as?

A

closely related processes

48
Q

what did Darwin do in 1844

A

write essay on natural selection as mechanism of descent with modification
- didn’t introduce theory publicly

49
Q

natural selection

A

process in which ind. w/ favorable inherited traits are more likely to survive and reproduce

50
Q

what 3 observations did Darwin explain in The Origin of Species

A
  1. unity of life
  2. diversity of life
  3. match between organisms and environment
51
Q

artificial selection

A

humans have modified other species by selecting and breeding ind. with desired traits

52
Q

Darwin’s 2 observations

A
  1. members of a population often vary in inherited traits
  2. all species can produce more offspring than the environment can support, and many of these offspring fail to survive and reproduce
53
Q

Darwin’s 2 inferences

A
  1. ind. whose inherited traits give them a higher probability of surviving/reproducing tend to leave more offspring
  2. unequal ability of ind. to survive/reproduce will lead to accumulation of favorable traits in population over generations
54
Q

who was Darwin influenced by?

A

Thomas Malthus
- noted potential for human population to increase faster than food supplies and other resources

55
Q

individuals with certain heritable characteristics _________ and ________ at a higher rate than other ind.

A

survive and reproduce

56
Q

what does natural selection increase over time?

A

adaptation of organisms to environment over time

57
Q

what evolves over time?

A

populations, not individuals

58
Q

what can only increase/decrease heritable traits that vary in a population?

A

natural selection

59
Q

what varies with different environments?

A

adaptations

Biology (35 decks)

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