Exam 2: Key Terms Flashcards

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1
Q

allele

A

different versions of a gene

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2
Q

codominance

A

the effect of both alleles is equally visible in the phenotype of the hetero zygote

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3
Q

dihybrid

A

individuals that are heterozygous for two traits

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4
Q

dominant allele

A

the allele that exerts a controlling influence on the phenotype in a gene heterozygote is said to be dominant

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5
Q

epistasis

A

when the phenotype effect of the alleles of one gene depends on the presence of certain alleles for another, independently inherited gene

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6
Q

gene

A

a piece of DNA that codes for genetic traits and are located on chromosomes

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7
Q

genetic cross

A

controlled mating experiment performed to examine how a particular trait is inherited

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8
Q

genetic trait

A

inherited characteristic of an organism that can be observed or detected in some manner

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9
Q

genotype

A

the allelic makeup of that individual with respect to the specified genetic trait

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10
Q

heterozygote

A

an individual whose genotype consists of two different alleles for a given phenotype

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11
Q

homozygote

A

an individual whose genotype consists of two copies of the same allele

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12
Q

hybrid

A

the offspring resulting from a cross between to purebreds (ex. mule & donkey)

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13
Q

incomplete dominance

A

produces an intermediate phenotype in the heterozygote (white & red make pink)
- no single allele completely dominates over the other and the heterozygote displays an “inbetween” phenotype

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14
Q

law of independent assortment

A

when gametes form, the alleles of a particular gene segregate during meiosis independetly of the alleles of other genes - located on separate chromosomes

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15
Q

law of segregation

A

the two copies of a gene are separated during meiosis and end up in different gametes

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16
Q

phenotype

A

the display of a particular version of a genetic trait in a specific individual

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17
Q

pleiotropy

A

a single gene influences two or more distinctly different traits (albinism)

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18
Q

recessive allele

A

an allele that has no effect on the phenotype when paired with a dominant allele in a heterozygote is said to be recessive

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19
Q

autosome

A

all chromosomes that don’t determine sex

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20
Q

chromosome theory of inheritance

A

all genes are located on chromosomes

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21
Q

crossing over

A
  • happens during meiosis
  • reciprocal exchange of segments of non sister chromatids
  • only thing that can unlink gene
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22
Q

deletion in relation to chromosomes

A

occurs when a piece of a chromosome breaks off and is lost (chromosomes with deleted will be shorter. only have 1 copy of gene)

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23
Q

duplication

A

a chromosome becomes longer because it ends up with two copies of a particular chromosome fragment (piece copied more than once)

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24
Q

genetic carrier

A

individuals that are heterozygous for a recessive disorder Ww

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25
Q

genetic linkage

A

genes that are positioned close to each other on the same chromosome tend to be inherited together
-located on the same chromosome

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26
Q

inversion

A

occurs when a fragment of a chromosome breaks off and returns to the correct place on the original chromosome, but with the genetic loci in reverse order (expresses the gene backward)

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27
Q

locus

A

the physical location of a gene on a chromosome

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28
Q

random fertilization

A

any sperm can fertilize any egg, so that the gentic combinations possible for a single fertilization is huge

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29
Q

sex chromosome

A

chromosomes that determine the sex (XY –> male XX –> female)

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30
Q

sex linked

A

genes found only on the X or Y chromosome

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31
Q

somatic mutation

A

occur in any cell of the body except the germ line cells (sperm & egg) and cannot be passed onto children

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32
Q

SRY gene

A
  • carried by the Y chromosome
  • a master gene that causes other genes located on autosomes to produce male sexual characteristics , without it develops as a female
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33
Q

test cross

A

a cross in which one parent is known to be a recessive homozygote and allows geneticists to evaluate whether an individual with a dominant phenotype is homo or heterzygote

34
Q

translocation

A

occurs when a broken piece from one chromosome becomes attached to a different, nonhomologous chromosome (cross over event of different chromosomes)

35
Q

trisomy

A

when a person inherits three copies of a chromosome (down syndrome –> chromosome 21)

36
Q

independent assortment of chromosomes

A

creates new combinations of alleles through the random distribution of maternal and paternal chromosomes into gametes during meiosis

37
Q

base pair

A

G-C
A-T(U)
-two nitrogenous bases held together by hdrogen bonds in a DNA molecule

38
Q

DNA polymerase

A

is the enzyme that connects nucleotides to make the new strand, using the old strand as the template
(proofreads and mismatches are detected and removed
-enzyme involved in DNA replication

39
Q

DNA repair

A
  1. recognition
  2. removal
  3. replacement
40
Q

genome

A

all the DNA based information in its chromosomes

41
Q

housekeeping gene

A

play an essential role in the maintenance of cellular activities in all kinds of cells

42
Q

non coding DNA

A

DNA that does not code for any kind of functional RNA

43
Q

ribosome

A

where proteins are made directed by mRNA molecules

44
Q

semiconservative replication

A

one old strand (template strand) is retained, in each new double helix and used as a template for a new complementary strand

45
Q

anticodon

A

mRNA binding site

46
Q

frameshift

A

insertion or deletion of one or two nucleotides

47
Q

deletion in relation to DNA

A

when a base is inserted into or deleted from a DNA sequence

48
Q

exon

A

segments of genes that actually code for amino acids

49
Q

insertion

A

when a base is inserted into a DNA sequence

50
Q

messenger RNA

A

delivers the genetic information, or instructions, from DNA to the ribosomes, where proteins are made

51
Q

gene promoter

A

sections of a gene/dna that function as an off/on switch for transcription.

52
Q

genetic code

A

the nucleotide triplets of DNA and RNA molecules that carry genetic information in living cells.

53
Q

intron

A

stretches of DNA that do not code for amino acid sequences of proteins and must be spliced out

54
Q

translation

A

process by which ribosomes covert the genetic information in mRNA into proteins

55
Q

regulatory DNA

A

can activate or inactive gene expression

56
Q

regulatory protein

A

interact with the environment and with regulatory DNA to promote or repress gene transcription

57
Q

Ribosomal RNA

A

assists in making the covalent bonds that liknk amino acids together to make a protein

58
Q

RNA Polymerase

A

synthesizes RNA using one strand of the DNA as a template

-binds to a segment of DNA near the beginning of a gene

59
Q

DNA fingerprinting

A

is the process of identifying DNA unique to a species or individual

60
Q

substitution

A

one base is substituted for another in the DNA sequence of the gene

61
Q

template strand

A

one of the two DNA strands is used as a template

62
Q

transfer RNA

A

transports the correct amino acid to ribosome, using the information encoded in the mRNA

63
Q

adult stem cell

A

undifferentiated cells in the adult body that produce only a limited number of different cell types

64
Q

RNA interference

A

selectively blocks the expression of a given gene

65
Q

directional selection

A

when individuals at one extreme of an inherited phenotypic trait have an advantage over other individuals in the population (one side)

66
Q

DNA hybridzation

A

target DNA is cut into fragments by restriction enzymes and converted to a single stranded form by treatments that break the hydrogen bonds holding the two strands together

67
Q

DNA miccroarray

A

consists of a solid support, the size of a microscope slide, on which known DNA sequences from a genome have been arranged in an orderly fashion

68
Q

gene flow

A

the movement of genes from one population to another

69
Q

gene therapy

A

seeks to correct genetic disorders through genetic engineering and other methods that can alter gene function

70
Q

genetic drift

A

a random process that can cause the gene pool of a population to change randomly from one generation to the next over time

71
Q

natural selection

A

is a nonrandom, directional process that shifts the genetic characteristics of a population in one direction that leads to adaptation over successive generations

72
Q

sexual dimorphism

A

males and females are distinctly different in appearance

73
Q

sexual selection

A

when individuals differ in inherited characteristics that affect their ability to get mates

74
Q

stem cell

A

undifferentiated cells with the extraordinary attribute of self renewal

75
Q

zygote

A

union of an egg and sperm

76
Q

adaptation

A

evolutionary process by which a population as a whole becomes better suited to its habitat

77
Q

artificial selection

A

the breeding of animals and plants with specific, desirable characteristics

78
Q

founder effect

A

occurs when a small group of individuals establishes a new population far from existing population

79
Q

disruptive selection

A

changes in population genetics in which extreme values for a trait are favored over intermediate values

80
Q

stabilizing selection

A

favor of the intermediate phenotypic traits