Chapter 3 - Genetics Flashcards Preview

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61

Mutations in somatic cells

can lead to tumors

62

mutations in gametes (sex cells)

transmitted to offspring

63

most mutations occur in regions of DNA that

do not code for proteins

are silent 

64

silent regions of DNA

not expressed in phenotype

65

mutations that change the sequence of the amino acids in proteins are most often

recessive

deleterious

66

Mutagenic Agents

(mutations)

mutagenic agents induce mutations

e.g. cosmic rays

X-rays

UV rays

radioactivity

chemical compounds - colchicine, mustard gas

67

mutagenic agents are generally

(mutations - genetic problems)

carcinogenic

68

colchicine

(chemical compound - mutagenic agent)

inhibits spindle formation

causes polyploidy

69

polyploidy

cells and organisms containing more than two paired (homologous) sets of chromosomes

70

carcinogenic

any substance directly involved in causing cancer

71

mutation types

(mutations - genetic problems)

gene

protein

72

gene mutation

nitrogen bases

added

deleted

subsituted

thus creating different genes

73

protein mutations

incorrect amino acid inserted in polypeptide chain

mutated protein produced

74

mutation

definition

genetic error with wrong/no base on DNA at particular position

75

examples of genetic disorders

phenylketonuria (PKU)

sickle-cell anemia

76

phenylketonuria (PKU)

definition

autosomal recessive 

genetic disorder

molecular disease

77

PKU caused by

 inability to produce proper enzyme for metabolism of phenylanine

 

78

result of PKU

degradation product (phenypyruvic acid) accumulates

can affect mental development

79

Sickle-cell anemia

definition

red blood cells become crescent-shaped because contain defective hemoglobin

80

sickle cell hemoglobin characteristic

carries less oxygen

81

sickle cell anemia caused by

substitution of valine (GUA or GUG)

for glutamic acid (GAA or GAG)

due to single base pair substitution in gene coding for hemoglobin

82

Molecular Genetics

DNA is basis for heredity

self-replication ensures that coded sequence will be passed on to successive generations

83

genes composed of

DNA

84

DNA contains 

information coded in sequence of base pairs

85

DNA provides

blueprint for protein synthesis

86

DNA reproduces via

self replication

87

DNA's ability to self-replicate is crucial for

cell division ---> reproduction

88

mutable

DNA is mutable and can be altered 

89

Changes in DNA and evolution

changes in DNA are stable and can be passed on from gen to gen ---> evolution

90

CUT PIE

cytosine, uracil, thymine

are

PYrimidines