Genes and Inheritance Flashcards
1
Q
DNA and RNA function
A
store and process molecular information
2
Q
what does DNA determine?
A
inherited characteristics
3
Q
what does DNA direct?
A
protein synthesis
4
Q
what does DNA control?
A
enzyme production
5
Q
what does DNA dictate?
A
metabolism
6
Q
what does RNA control?
A
intermediate steps in protein synthesis
7
Q
what are nucleotides?
A
building blocks of nucleic acids
8
Q
three parts of nucleotides
A
5 carbon sugar
phosphoric acid
nitrogenous base
9
Q
what sugar is in DNA?
A
deoxyribose
10
Q
what sugar is in RNA?
A
ribose
11
Q
what are the purines?
A
adenine
guanine
12
Q
what are the pyrimidines?
A
thymine (DNA)
uracil (RNA)
cytosine
13
Q
what base is replaced in RNA ?
A
DNA has thymine and is replaced by uracil in RNA
14
Q
what structure is DNA?
A
double stranded
15
Q
what bases pair in DNA?
A
A-T
C-G
16
Q
what types of strands does DNA have?
A
coding and template strands
17
Q
where is DNA present?
A
nucleus and mitochondria
18
Q
arrangement of DNA in nucleus
A
chromatin
chromosomes
19
Q
arrangement of DNA in chromatin
A
loosely coiled
20
Q
arrangement of DNA in chromosomes
A
tightly coiled
21
Q
what is DNA complexed with?
A
proteins (histones)
22
Q
how many chromosomes are there in a cell?
A
46 (23 pairs)
23
Q
DNA arrangement in mitochondria
A
rings
24
Q
what are genes?
A
segments of DNA that provide instruction for protein synthesis
25
what is the genome?
entire complement of cellular DNA
26
where does mitochondrial DNA come from?
maternally inherited
27
specific structure of mitochondrial DNA
double-stranded rings
28
how many genes are in mitochondrial DNA?
37
29
how many mitochondria can diseases linked to mDNA affect?
variable number
30
what types of diseases are mDNA diseases?
progressive
31
what do mDNA diseases commonly involve?
neuromuscular transmission
32
examples of mDNA diseases
Kearns-Sayre disease
| Myoclonus epilepsy
33
what does RNA handle?
aspects of protein synthesis
34
3 forms of RNA
messenger RNA mRNA
ribosomal RNA rRNA
transfer RNA tRNA
35
what does mRNA do?
carries genetic information from nucleus to cytoplasm
36
how is information transmitted on mRNA?
as codons
37
when is mRNA formed?
during transcription of a gene
38
what does rRNA do?
makes up ribosomes
39
what does tRNA do?
delivers amino acids to ribosomes during protein synthesis
40
how does tRNA have specificity?
anticodons
41
what are triplets?
three base sequences of coding strand
42
what do triplets specify?
amino acid sequence of proteins
| start and stop of transcription
43
characteristic of triplets
universal across nature
| redundant
44
what does redundancy of triplets allow?
changes (mutations)
45
where is DNA during transcription?
trapped in nucleus
46
where does protein synthesis occur?
cytoplasm
47
what is the intermediary in transcription?
mRNA
48
what is synthesis of mRNA complementary to?
base sequence of a gene
49
what does synthesis of mRNA require?
separation of strands
50
what binds to promotor region?
RNA polymerase
51
what happens after RNA polymerase binds to promoter strand?
RNA polymerase "reads" coding strand
52
transcription-what do three base sequences become?
codons
53
what happens after mRNA is synthesized?
undergoes processing
54
what strand gets transcribed?
Only one strand gets transcribed (coding strand)
55
transcription-what are exons?
coding sequences
56
transcription-what are introns?
intervening non-coding sequences
57
what happens to introns and exons?
introns are removed and exons are spliced
58
what happens if introns and exons are rearranged?
different proteins are synthesized
59
where does processed mRNA go?
cytoplasm
60
what "reads" mRNA?
ribosomes
61
amount of tRNAs
tRNAs exist for all 20 amino acids
62
tRNA anticodons
specific and complementary to codons of mRNA
63
what does tRNA do?
deliver amino acids to ribosomes
64
what links amino acids together?
ribosomes
65
how is the amino acid sequence determined?
mRNA codons
66
what post-translational modification do proteins undergo?
folding
addition of lipids or carbohydrates
linkage to other proteins
67
location and product of transcription of DNA
nucleus
| produces complementary mRNA
68
location(s) and product of translation of mRNA
cytoplasm
ribosomes
produces amino acid chain with specific sequence
69
product of post-translational modification
mature/functional protein
70
are genomes different between cells?
no, all nucleated cells have same genome
71
requirements of different cells
different proteins for functionality and different proteins for separate conditions
72
how can rates of transcription be regulated?
transcription factors
| inducers, repressors, operons
73
inducers
regulates gene expression by disabling repressors
74
repressors
inhibits the expression of one or more genes by binding to the operator or associated silencer
75
operon
functioning unit of DNA containing a cluster of genes under the control of a single promoter
76
promoter
contains specific DNA sequences such as response elements that provide a secure initial binding site for RNA polymerase
77
what is required for cell division?
DNA replication
78
what is required for DNA replication?
both DNA strands
79
what does each DNA strand serve as in DNA replication?
template for new complementary starnd
80
function of semiconservative replication
1 strand of "parent" DNA present in each "daughter" double strand
81
what does DNA polymerase do?
forms complimentary strands based on sequence of parent strands
82
what does DNA replication result in?
diploid cell
83
diploid cell
twice normal amount of DNA
84
examples of DNA replication errors
base addition/deletion
base change
mutations
85
where do DNA replication errors usually occur?
rapidly dividing cells
86
what can DNA replication errors result in?
altered proteins
87
what recognizes/repairs damage in DNA replication?
endonucleases
88
what else can cause DNA mutations?
radiation
chemicals
environment
89
what are DNA mutations important in?
carcinogenesis
90
what are chromosomes?
tightly coiled nuclear DNA
91
when are chromosomes visible?
only during cell division
92
how many pairs of chromosomes do somatic cells have?
23
93
breakdown of chromosomal pairs
22 autosomes
| 1 sex chromosomes (XX or XY)
94
what are autosomal pairs?
homologous-genes affect same traits
95
types of genes in sex chromosomes
genes affect different traits
96
what does the presence of Y chromosome determine?
male pheontype
97
what type of cell is a sex cell?
haploid (half normal number)
98
what is lyonization?
random inactivation of all but one X chromosome in a cell
| -maternal or paternal X
99
when does lyonization occur?
early in embryogenesis
100
what is an inactive X called?
barr body
| same X active in all cell's progeny
101
what is responsible for mosaic pattern in calico cats?
lyonization
102
example of "unlucky" lyonization
female color-blindness
103
phases of cell cycle
2 "gap" phases with intervening "S" phase
104
what happens during S phase of cell cycle?
DNA replication
105
G0 phase
non-dividing/resting cells
106
what does mitosis do?
equally divides DNA
107
cytokinesis
equally divides cytoplasm and organelles
108
what cells undergo mitosis?
somatic cells
| -occurs in epithelium, hyperplasia, regeneration
109
4 phases of mitosis
prophase
metaphase
anaphase
telophase
110
what is mitosis coordinated with?
cytokinesis
111
what does mitosis result in?
genetically identical daughter cells
112
what is meiosis?
double division of replicated DNA
113
what does meiosis occur in?
only sex- (germ) cell precursors
114
what does meiosis result in?
haploid cells
| germ cells, sex cells, gametes, etc.
115
what does meiosis involve?
"crossing over" of portions of replicated chromosomes in meiosis
116
what does crossing over result in?
genetic variability
117
how many haploid cells are produced for each male precursor?
4
118
how many haploid cells are produced for each female precursor?
1 haploid cell
| 3 (or less) polar bodies
119
what causes genetic variation?
- random distribution of maternal and paternal chromosomes to gametes
- crossing over of portions of chromosomes between replicated pairs
- translocations between nonhomologous chromosomes
- basics of evolution
120
what can genetic variation result in?
nonviability
121
gene
functional segment of chromosome, directs protein synthesis
122
locus
gene's position on a chromosome
123
p arm chromosome
short arm i.e. 3p22
124
q arm chromosome
long arm i.e. 3q21
125
allele
alternate forms of gene at same locus
126
homozygous
both chromosomes of a pair carry same allele
127
heterozygous
chromosomes of a pair carry different alleles
128
genotype
chromosomes and genes
129
phenotype
characteristics resulting from genotype and interaction with environment
130
expression
degree to which a gene manifests in phenotype
131
how can expression vary?
mild to severe
132
penetrance
ability of a gene to express its phenotype
133
how can penetrance vary?
0 to 100%
134
simple inheritance
phenotype determined by interaction between single pair of alleles
135
what does simple inheritance follow?
Mendelian rules of inheritance
136
strict dominance
dominant allele is always expresses in phenotype
137
when will recessive allele be expressed in strict dominance?
recessive allele will be expressed only if same allele is present on both chromosomes
138
codominance
heterozygous individual exhibits both phenotypes
139
incomplete dominance
heterozygous alleles produce intermediate phenotype
140
what can be used to predict phenotype of offspring?
Punnett squares
141
what is polygenic inheritance?
interactions among several genes responsible for producing phenotype
somewhat predictable
142
do Punnett squares work with polygenic inheritance?
no
143
mechanisms of polygenic inheritance-multiple alleles
more than one allele affects same trait
144
mechanisms of polygenic inheritance-suppression
one gene suppresses another, 2nd gene doesn't affect phenotype
145
mechanisms of polygenic inheritance-complementary
two genes mutually dependent on each other
146
multifactorial inheritance
polygenic inheritance with influences from environment as well
147
sex-linked inheritance also called
"x-linked"
148
what does x chromosome carry?
many genes related to somatic structure
149
what does y chromosome carry?
male-determining genes
150
chromosomes of females
46XX
151
chromosomes of males
46XY
152
what contributes x or y to fertilization?
spermatozoa
153
how are sex-linked disorders inherited?
recessive fashion
154
function of females in sex-linked inheritance
can be carriers and pass to male offspring
155
aberrations
chromosome abnormalities
156
examples of aberrations
extra or absent chromosomes
| chromosomal breaks
157
what do aberrations usually result in?
abortion or stillbirth
158
mutations
changes in nucleotide sequence of a gene
159
types of mutations
can be spontaneous or induced
160
examples of mutations
substitution, deletion or insertion (or combinations) of bases
161
human genome project
world's larges collaborative project
| 1990-2003
162
how many base pairs sequenced in human genome project?
3.2 billion
163
how many protein-coding genes are there?
20,000-25,000
| doc was shocked
164
how much of genome is shared across individuals?
99.9%
165
how much of genome accounts for human diversity?
0.1%
166
how many different single-gene disorders have been described?
10,000
