Genetic Control of Cell Function and Inheritance; Week 2 Ch. 6 Flashcards
(135 cards)
1
Q
Congenital
A
Present at birth
2
Q
Genotype
A
Sum total of genetic info in cells;
-23 maternal & 23 paternal chromosomes unite at conception
3
Q
Phenotype
A
physical manifestation of genetic info
4
Q
Penetrance
A
% in population w/ particular genotype in which the genotypes is phenotypically manifested
-physical characteristics evident
5
Q
Expressivity
A
How the gene is expressed
6
Q
Homozygotes
A
AA or aa
7
Q
Heterozygotes
A
Aa
8
Q
Polymorphism
A
presence of genetic variation w/in. a population upon which natural selection can operate
9
Q
Recessive Trait
A
expressed only in homozygous pairing
10
Q
Dominant Trait
A
expressed in either homozygous or heterozygous pairing
11
Q
Carrier
A
person who is homozygous for a recessive trait, but does not manifest trait (Aa)
12
Q
DNA
A
- every cell=same genetic info
- every gene passed to daughter cells w/ every division
- 5-carbon sugar (deoxyribose) & a phosphate group
13
Q
Phosphodiester bonds
A
join group of 1 sugar to 3-carbon of next sugar
-results in 1 of 4 nucleotide bases
14
Q
Nucleotide bases
A
-Make up the genetic code
-Adenine
Thymine
Guanine
Cytosine
15
Q
double helix
A
- formed by base pairs
- patterns formed are specific to the proteins they make
16
Q
Chromosomes
A
-46 long, double-stranded chains of specific nucleotides
17
Q
Pyrimidines
A
- single-ring structures
- Cytosine and Thymine
18
Q
Purines
A
- Double-ring structures
- Guanine and Adenine
19
Q
Hydrogen Bonds
A
- Weak bonds
- Formed by bases
- (G+C) (A+T)
20
Q
Double Helix ladder
A
sides of ladder= sugar-phosphate bonds
rungs of ladder=bases
complete turn every 10 pairs
21
Q
Nucleosomes
A
fors as helix winds around histones
22
Q
Histones
A
facilitates compaction of DNA into nucleus of the cell; protein
23
Q
Chromatin
A
DNA couple w/ histones and other nuclear proteins
24
Q
DNA Replication is…
A
NOT THE SAME AS TRANSCRIPTION
25
DNA replication 1
- DNA double helix separates
| - new nucleotides paired w/ DNA template strands
26
DNA replication 2
-initiator proteins pry DNA strands apart at replicating origins
27
replications origins
specific places on chromatin that initiator proteins target to pry DNA strands apart (initiate DNA replication 2)
28
DNA replication 3
DNA helices rapidly unwinds and separates DNA strands
29
DNA replication 4
Helix-destabilizing proteins bind to exposed DNA strands
| -**They are kept apart until replication
30
DNA replication 5
Topoisomerases cut nicks in DNA
31
topoisomerases
allows DNA to unwind w/o tangling (DNA replication 5)
32
DNA replication 6
ligase repairs nicks in DNA
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DNA replication 7
- DNA polymerase binds single DNA strands
- complementary DNA strand begins to form
- matches appropriate base to template base
- catalyzes formation of sugar-phosphate bonds that form backbone of DNA strand
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DNA replication 8
- Replication proceeds along DNA strand
- from 3' end toward 5' end only
- Replication is ASYMMETRICAL
35
Continuous polymer
leading strand in DNA replicated
36
Okazaki fragments
- Short fragments;
- Lagging strand of DNA that is synthesized into short fragment
- Sealed together by DNA ligase
- Forms unbroken DNA strand
37
TelomerASE
needed to replicate telomeres
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TelomerES
end of chromosome
39
Replication of telomeres
- 3' end of double helix ALWAYS LONGER and loops around and tucks back in
- prevents nuclear enzymes from trying to attach to eachother
40
Endonucleases
recognize local distortions of DNA and removes distorted region
41
DNA ligase
Sticks DNA right back into plase
42
DNA polynerase
removes incorrect nucleotides & replaces w/ correct ones
43
single-strand breakage
easily repaired
44
double-strand breakage
- BAD
- errors accumulate
- EXAMPLE:
* proto-oncogen breakage=failure to repair=cancer
* tumor suppressor gene breakage=failure to repair=cancer
45
DNA mutations
inherited alteration of genetic material
46
aberrations in chromosomes
- Point mutation
- Frameshift Mutation
- Spontaneous mutation
47
Point mutations
SUBSTITUTION of one base pair for another
| **may cause affected codon (3 base pairs) to signify abnormal amino acid
48
Frameshift mutation
loss/addition (+/-) of one or more base pairs
* *change in entire "reading frame"
* *rearrangement of base Paris
* **remaining codon triplets will have greatly altered amino acid sequences
49
Spontaneous mutation
d/t environmental agents, chemicals, radiation
| **can raisin somatic cells OR germ cells
50
mutational hot spots
ares on chromosomes w/ high mutation rates (spontaneous mutation)
51
Spontaneous mutation common factors
```
nitrogen mustard
vinyl chloride
alkylating agents
formaldehyde
sodium nitrite
```
52
Amino Acids
cells have 20 different types
| **join in a specific sequence to form a particular protein
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triplet
3 nucleotides
54
codons
code for each of the 20 amino acids
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stop codons
signal to the end of a protein
56
RNA and Ribosomes
used to make valuable proteins
57
RNA
sugar molecule=ribose
single-strand
uracil replaces thymine
58
mRNA (Messenger RNA)
5% of total RNA
forms template for protein synthesis
carries protein code to the cytoplasm
59
tRNA (Transfer RNA)
- delivers activated form of amino acids to protein molecules in the ribosomes
- interacts w/ ribosomes and mRNA in translatin
60
rRNA (Ribosomal RNA)
80% of total RNA
involves physical structure in cytoplasm where protein synthesis takes place
**Small RNA=hangs out in nucleus
61
Transcription
mRNA is synthesized from single-stranded DNA template
62
Sense strand
used to form mRNA
| can be top/bottom, depends on specific gene
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nonsense/antisense strand
other strand of DNA not used in RNA transcription
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Transcription 1
RNA polymerase binds to promoter region/site
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RNA polymerase
enzyme complex used in transcription
66
Transcription 2
after RNA polymerase binds
* *directs DNA double-helix seperation
* *catalyzes synthesis of RNA message
* *matches appropriate RNA bases to DNA template
67
Transcription 3
mRNA transport to cell cytoplasm through nuclear membrane pores
68
nuclear membrane pores
contain completes that inspect mRNA for any RNA debris
| **checks & balances
69
Transcription 4
mRNA directs synthesis of protein in cooperation w/ tRNA and ribosomes
70
POSSIBLE TRANSCRIPTION MALFUNCTIONS
RNA encounters introns--> spliceosomes remove introns
71
introns
unwanted bases
72
exons
wanted bases
| **important in evolution of new genetic info and gene regulations
73
Post-transcriptional activities
modification of RNA
**remove segments, add terminal trimmings, add terminal additions, remove internal segments, splice areas/base modifications
74
translation
mRNA used to direct synthesis of a protein
| **mRNA read lineraly
75
mRNA codons
do not recognize amino acids
76
tRNA
translates amino acids so mRNA can recognize them
77
ribosomes
large complexes of proteins and RNA assembled in nucleolus
* *Needed for:
- line up tRNA on mRNA
- catalyze peptide bonds that hold together amino acids
* *find starting place on mRNA
* *set correct reading frame for codon triplets
* *move along mRNA
* *translate nucleotide sequence into mine acid sequence
78
chaperone proteins
folds new proteins into shape depending on:
- polar
- nonpolar
- charged
* *essential in taking care of damaged proteins and from oxidative stress/free radicals
79
Gene expression
degree to which a gene or group of genes is active
80
transcription factors & promoter regions
determine which gene is expressed
81
structural genes
specify amino acid sequence of a polypeptide chain
82
regulator genes
regulatory function w/o stipulating the structure of protein molecules
83
operon
formed by sequence of genes controlling the regulation of protein synthesis
84
gene repression
regulatory gene reduces/prevents gene expression
85
repressor proteins
inhibit assembly of transcription factors by:
**binding/physically blocking promoter region
**compacting DNA so it's difficulty to pry open **interfere w/ activator proteins
binding/inhibiting transcription factors
86
post translational processing
involves proper folding of newly synthesized polypeptide chain
87
epigenetics
gene regulation that occurs at transcription or translation level
88
DNA methylation
* attachment of methyl group to cytosine-->renders genes silent
* prominent role in health and disease
89
aberrant methylation
can leads to--> misregulation of tenor-suppresor genes and oncogenes
90
Heavily methylated gene
DNA less likely to be transcribed into mRNA, bc gene is too thick to pry open
91
histone modification
acetylation and deacytlation
| * can alter expression state of chromatin
92
Chromatin
critical role in determining development of cells
93
Euchromatin
open state in which most/all nearby genes are transcriptionally active
**AT LEVEL OF TRANSCRIPTION**
94
Heterochromatin
closed state; most/all nearby genes are transcriptionally Inactive
**AT LEVEL OF TRANSCRIPTION**
95
ncRNA (Non-coding RNA)
RNA splicing and DNA replication
| *like a sponge--> "sop up" complementary RNAs and then inhibit the function
96
miRNA (Micro RNA)
* resemble a hair pin
* modulate the stability and transitional efficiency of exiting messenger RNAs
* specifically work w/ introns
* regulate diverse signaling pathways
* *Oncomirs**
97
Oncomirs
miRNA that stimulates cancer development/progression of cancer
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Genome
the environment
99
Totipotent
embryonic cells w/ ALL powers to give rise to a ALL cell types
100
epigenetic modification
eagles cells to achieve diverse functions
101
DNA Methylation initial occuence
as early as 10 days genome-wide
102
Houskeeping genes
Encoding Histones, DNA and RNA polymerase, and Ribosomal RNA genes
103
imprinted genes
transcriptionally "silent" genes
| copy inherited through sperm or egg is inactivated and remains inactive for LIFE
104
biallelic expression
largest subset
| maternal&paternal inherited genes contribute to offspring phenotype
105
monoallelic expression
small subset
| maternal copy randomly chosen for inactivation in some cells, paternal copy in others
106
Genetic conflict hypothesis
developed to explain imprinting of genes
107
imprinting of maternally inherited genes
reduced offspring size
108
imprinting of paternally inherited genes
increased offspring size
109
Methylation patterns
substantial differences in patterns of DNA sequences on somatic cells noticed w/ aging
**epigenetic patterns=important part of aging process**
110
autosomes
22 pairs of chromosomes alike in males and females
111
Sex chromosomes
23rd pair
| determine sex of a person
112
cytogenics
study of chromosomes
113
karyotype
ordered display of chromosomes
114
chromatids
2 identical linear chromosome units
115
centromere
point at X where 2 chromatids join
116
Chromosomes - "p"
short arm
117
Chromosomes - "q"
long arm
118
Xp23
Short arm of X chromosome, band 2, region 3
119
Xq21
Long arm of X chromosome, band 2, region 1
120
mitosis
somatic cells
| results in formation of 23 chromosomes
121
meiosis
```
limited to germ cells
forms haploid cells from diploid cells
*reproductive cells*
*fight, fright, feed, and breed*
involves two division of chromosomal DNa
```
122
Meiosis- 1st division
two cells each w/ 46 chromosomes
| **1-3 crossover vents occurs
123
Meiosis- 2nd division
sister chromatids pull apart
| **4 haploid cells formed w/ 23 chromatids
124
alleles
alternate forms of genes
| one from each parents
125
locus
position genes occupy on a chromosome
126
genetic maps
use linkage studies to estimate distance b/w chromosomal landmarks
allows us to look at crossover
127
physical maps
measures actual distance b/w chromosomal elements in biochemical units
128
linkage studies
involved linked genes on the same chromosome
| define degree of linkage based on physical distance from each other on the chromosome
129
recombination
process of forming such new arrangements of alleles
130
dosage studies
measures enzyme activity
131
hybridization studies
use sequences of DNA or RNA to locate genes that do not express themselves in cell culture
132
Recombinant DNA technology
gene isolation and cloning
133
Gene therapy
uses transferred genes to replace defective genes or selectively inhibits deleterious genes
134
DNA fingerprinting
uses gene technology to detect slight variations in genomes of different people
135
iRNAi
naturally occurring process in which small pieces of double-stranded RNA suppresses gene expression
* gene silencing
* reverse genomic studies
