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Bio 121 > Test 4 > Flashcards

Test 4 Flashcards

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Biology 101 flashcards
1
Q

genotype

A

the genetic make up of an organism

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2
Q

phenotype

A

the observable physical characteristic

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3
Q

gene

A

section of DNA that codes fro a specific protein product or RNA molecule

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4
Q

transcription

A

the process of RNA synthesis from a DNA template

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5
Q

mRNA

A

an RNA molecule made as a complementary copy of a gene formed as a single strand by a mechanism similar to DNA replication

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6
Q

RNA polymerase

A

the enzyme responsible for attaching RNA nucleotides together in the sequences specified by the DNA

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7
Q

introns

A

segments/sequences not specifically involved in coding for a polypeptide

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8
Q

Exons

A

segments/sequences that are placed together to form the final mRNA molecule to be used by a cell

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9
Q

translation

A

the nucleotide sequences of mRNA is used to determine the amino acid sequence

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10
Q

codon

A

every set ig 3 bases in the mRNA molecule

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11
Q

genetic code

A

consists of 64 possible codons, 61 of which code for amino acid

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12
Q

genetic engineering

A

the insertion of DNA from one species into another to allow donor DNA sequences to be expressed by the recipients

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13
Q

rRNA

A

produced in the nucleus by transcription, and it joins with proteins to form the subunits of ribosomes.

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14
Q

tRNA

A

produced in the nucleus by transcription, and it transports specific amino acids to a ribosomes to align them correctly to form a new polypeptide chain

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15
Q

anticodon

A

a series of three bases on a tRNA molecule that will pair with the complementary codon on an mRNA molecule

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16
Q

what is the DNA template used for?

A

to generate molecules that will be used as working copies to be read in the making of new protein molecules

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17
Q

What “start signal” (in the DNA template) does an RNA polymerase enzyme use in order to know where to start in transcribing (creating) a new mRNA molecule?

A

AUG

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18
Q

What could happen to an mRNA molecule that is sent out into the cytoplasm without a 5’ cap and a poly(A) tail?

A

(It could broken down by cell enzymes (after being perceived as an “purposeless” molecule, and a ribosome might also have difficulty attaching to it.)

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19
Q

Where in a eukaryotic cell can translation occur?

A

transcription occurs in the nucleus and translation occurs at ribosomes in the cytoplasm

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20
Q

Why is the genetic code described as redundant, and how does that ensure that many “third letter” codon mutations will be silent?

A

there are often 2 or more codons with different third bases that “code for” the same amino acid

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21
Q

How does the universality of the genetic code make genetic engineering possible?

A

all genetic code is the same amongst all living organisms

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22
Q

What signal allows the process of translation to come to an end?

A

UAA, UGA, UAG

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23
Q

Are mutations always detrimental?

A

No –they can sometimes confer beneficial characteristics on an organism, and provide the “raw material” for evolution to occur!

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24
Q

What amino acid corresponds to the “start codon” carried by every mRNA molecule?

A

AUG

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25
Q

point mutation

A

change in one base pair of a gene

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26
Q

silent mutation

A

mutations that are not evident in an organisms phenotype due to the fact that the letter sequence change

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27
Q

missense mutations

A

switch an amino acid codon into a codon for a different amino aid giving the protein different functional characteristics

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28
Q

nonsense mutations

A

switch an amino acid codon into a stop codon

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29
Q

insertion mutation

A

addition of nucleotide pairs in a gene

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30
Q

deletion

A

removal of nucleotide pairs in a gene

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31
Q

frameshift mutation

A

alteration in the way that all “downstream” codons will be read

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32
Q

spontaneous mutations

A

mutations can occur naturally due to errors made during DNA replication, DNA repair, or DNA recombination

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33
Q

mutagens

A

chemical or physical agents that interact with DNA to cause mutation

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34
Q

How do insertion and deletion mutations cause frameshift mutations? Why would frameshift mutations be very unlikely to be “silent?”

A

because the insertion of an amino acid would cause the rest of the amino acids to change. the change would likely cause a silent mutation because many of the amino acids make the same codon

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35
Q

Will all mutations be passed on?

A

no

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36
Q

What kinds of conditions can cause a point mutation to also be a silent mutation?

A

When the amino acid changes but doesn’t change the outcome

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37
Q

evolution

A

refers to the changes in the genetic makeup go in biological populations over time

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38
Q

population

A

group of individuals of a single species that live and interbreed in a particular geographical area

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39
Q

microevolution

A

changes in the genetic makeup of populations

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40
Q

macroevolution

A

large-scale evolutionary changes that can lead to speciation

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41
Q

natural selection

A

differential survival and reproduction between individuals within a population

42
Q

artificial selection

A

the selective breeding of organisms by humans to emphasize preferred characteristics of offspring

43
Q

mutation

A

any change in the nucleotide sequence of an organisms DNA

44
Q

adaptation

A

a trait that is favored by natural selection

45
Q

species

A

a group. of populations whose individuals have the potential to interbreed and produce fertile offspring under natural conditions

46
Q

gene pool

A

total aggregate of genes in a population at any given time

47
Q

fixed allele

A

when all the members of a population only contain one type of allele for a given trait

48
Q

Hardy-Weinburg equilibrium

A

must satisfy the five conditions of evolution

49
Q

sexual selection

A

nonrandom mating in which an organisms phenotype impacts its ability to attract mates

50
Q

genetic drift

A

a phenomenon that can occur in a small populations when random chance events impact allele frequencies

51
Q

bottleneck effect

A

occurs when a number of individuals in a population are removed from the gene pool due to environmental disaster

52
Q

founder effect

A

occurs when a new population is established by a few individuals with limited genetic variety

53
Q

gene flow

A

interbreeding via genetic change between populations

54
Q

How likely is it that all of the requirements for Hardy-Weinberg equilibrium will actually be met in populations in the wild?

A

very low

55
Q

Why are small populations more prone to the effects of genetic drift

A

(By their nature, small populations will contain less genetic diversity than larger populations, and that genetic diversity will be harder to “maintain” due to chance/random events that may occur.)

56
Q

On what continent did Darwin first gather many of the examples that he would later use in forming his theory of evolution by means of natural selection?

A

South America

57
Q

What scientist was a contemporary of Darwin’s who independently came to a similar understanding of evolutionary theory (causing them to present their ideas jointly)?

A

Alfred Russel Wallace

58
Q

Did Darwin have a good understanding of the genetics underlying evolutionary change? Why or why not?

A

No genetic evidence was available at the time he took his first voyage, so he had no knowledge

59
Q

What are the main inferences/tenets underlying Darwin’s concept of evolution via natural selection

A

overproduction, inheritance/competition, and natural selection.

60
Q

Is artificial selection likely to produce the same outcomes that natural selection would? Why or why not?

A

Not necessarily. If the outcome is favorable for humans, then it likely would, but if it is unfavorable, then the outcomes would be different

61
Q

What produces the genetic variation between individuals that natural selection will act upon?

A

mutations

62
Q

Do all mutations have negative impacts on an individual?

A

no

63
Q

Will an adaptation that helps an organism to survive and reproduce in one environment cause it to be equally successful across all other environments? Why or why not?

A

no, adaptation helps the organism survive BASED on its environment, so different environments will required different adaptations

64
Q

Can an individual organism undergo evolutionary change to better suit its environmental conditions? Why or why not?

A

no, adaptation occurs on a population level, not an individual level

65
Q

Does the Hardy-Weinberg principle best describe evolving or nonevolving populations?

A

non evolving

66
Q

what are the five conditions that must be met in order for Hardy-Weinberg equilibrium to be present:

A

no mutations, random mating, no natural selection, a large population size, and no gene flow into/out of the population.

67
Q

In the Hardy-Weinberg equation, p2 + 2pq + q2= 1.0, what does the “p” stand for?

A

The dominant allele (A)

68
Q

In the Hardy-Weinberg equation, p2 + 2pq + q2= 1.0, what does the “q” stand for?

A

the frequency of the recessive allele (a)

69
Q

What is the single advantage of sexual reproduction over asexual reproduction?

A

increased genetic variety

70
Q

While new alleles arise within populations due to mutation, does every mutation produce a new allele?

A

No, some mutations are silent and therefore cause no change

71
Q

Darwinian Fitness

A

the contribution that an individual makes to the gene pool of the next generation

72
Q

relative fitness

A

the contribution of one specific genotype to the next generation

73
Q

directional selection

A

occurs when one phenotype extremes are favored over an intermediate phenotype

74
Q

diversifying selection

A

occurs when one phenotypic extreme of the other is favored over any intermediate phenotype

75
Q

stabilizing selection

A

occurs when an intermediate phenotype is favored over any extreme phenotype

76
Q

Why are evolutionary processes more “observable” in species with short generation times?

A

because most mutations occur over multiple lifetimes while these mutations can occur when the human lifetime

77
Q

What are the limitations on natural selection

A

(1)evolutionary change must work with pre-existing structures and cannot “start from scratch”
(2) adaptations are often compromises and are rarely perfect solutions
(3) random events and genetic drift can lead evolution in a direction that is not truly adaptive
(4)natural selection can only act on the genetic diversity currently present in a population.

78
Q

mitosis

A

asexual cell division to produce clonal cell s

79
Q

asexual reproduction

A

reproduction that involves one parent and occurs without the fusion of gametes

80
Q

clone

A

genetically identical to the parent

81
Q

chromosomes

A

made of DNA tightly wound around histone proteins

82
Q

chromatin

A

unwind DNA that is loosely looped around histone proteins

83
Q

interphase

A

a metabolically active stage that alternates with mitosis

84
Q

g1 phase

A

centered on intense biochemical and growth activity

85
Q

S phase

A

involves DNA replication

86
Q

sister chromatids

A

identical copies of a DNA molecule that are held together at their centers

87
Q

g2 phase

A

centered on protein synthesis and completing final preparations for cell division

88
Q

prophase

A

Chromatin thickens (condenses) into chromosomes

89
Q

Telophase

A

Chromosomes de-condense
Nuclear membranes reappear around each set of copies
This creates two distinct nuclei in the same cell
Spindle fibers completely disappear

90
Q

cytokinesis

A

division of the cytoplasm creating two new cells, follows mitosis

91
Q

sexual reproduction

A

happened when haploid male and female gametes fuse to produce a diploid zygote

92
Q

gametes

A

haploid sex cells

93
Q

zygote

A

a diploid cell created from two haploid cells that will develop into genetically unique individual

94
Q

haploid

A

posessing one set of chromosomes

95
Q

diploid

A

processing two sets of chromosomes

96
Q

homologous chromosomes

A

pair of chromosomes that code for the same informations, with one of each pair obtains from one parents and from the other

97
Q

meiosis

A

the process that reduces chromosome number from the diploid to haploid in those cells that can participate in sexual reproduction

98
Q

crossing over

A

gene swapping

99
Q

What are the products of asexual reproduction (mitosis)?

A

2 haploid daughter cells

100
Q

What would be an advantage and a disadvantage of asexual reproduction?

A

advantage: there is no time wasted by finding a mate
disadvantage: Because offspring are identical none of them will be any better adapted to their environment.

101
Q

What stages comprise interphase?

A

G1 phase (cell growth), followed by S phase (DNA synthesis), followed by G2 phase (cell growth).

102
Q

What are the products of sexual cell reproduction

A

a zygote

Bio 121 (4 decks)

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