Human Genome and Gene Expression Flashcards
1
Q
what type of molecule is a double helix
A
DNA
2
Q
what molecule is each human chromosome
A
a single linear DNA molecule with a string of nucleotides that spell out genes
3
Q
when was the first full human genome sequenced
A
in 2003
4
Q
what does a human genome consist of
A
around 3 billion basepairs
5
Q
how many genes are in a human genome
A
25,000
6
Q
what percentage of genome is protein coding regions
A
around 2%
7
Q
what makes up 50% of a genome
A
repetitive DNA of truly unknown function
8
Q
what are polymorphisms
A
sites in the DNA
9
Q
what are alleles
A
different versions or variants of DNA sequences
10
Q
how much does it cost to obtain one human genome
A
$1000
11
Q
what is a gene
A
the entire nucleic acid sequence
12
Q
what is the purpose of a nucleic acid sequence
A
it is necessary for synthesis of a functional polypeptide
13
Q
what RNA molecules do DNA regions code for
A
tRNA, rRNA, and mRNA
14
Q
TRUE OR FALSE: tRNA, rRNA, and mRNA are not genes, but are RNA molecules
A
FALSE: they are considered genes as well as RNA molecules
15
Q
where do genes lie amidst
A
a large expanse of nonfunctional, non coding DNA and genes
16
Q
what are different versions of genes called
A
alleles
17
Q
how much DNA is in each diploid human cell
A
two meters of DNA in length
18
Q
how does so much DNA fit into a tiny nucleus
A
fold with proteins
19
Q
how big is a nucleus
A
5 micrometer
20
Q
how many pairs of chromosomes are in a cell’s nucleus
A
23 pairs
21
Q
what are pairs of chromosomes called
A
homologous chromosomes
22
Q
what are autosomes
A
the 22 pairs of chromosomes of homologous chromosomes
23
Q
what are sex chromosomes
A
the 1 pair that contains genes which establish gender
24
Q
what are diploids
A
somatic cells that have 46 chromosomes
25
how do diploid cells divide
mitosis
26
what are haploid cells
germ cells that create gametes that have only 23 chromosomes
27
how do haploid cells divide
meiosis
28
what are somatic cells also known as
body cells
29
what are germ cells also known as
sex cells
30
what is created by a genotype
a range of phenotypes
31
what influences phenotypes
the environment
32
how many copies of each gene do we have
2
33
what is a dominant allele
a single copy of the allele that is sufficient to manifest the phenotype
34
what is a recessive allele
an allele that is only manifested when an organism has two of this type of allele
35
what is homozygous dominant
two dominant alleles
36
what is homozygous recessive
two recessive alleles
37
what is heterozygous dominant or simply heterozygous
one dominant allele and one recessive allele
38
what is a carrier
heterozygote that has a single recessive allele contributing to trait, but since it is recessive the trait is not expressed
39
what is one-trait cross
considers the inheritance of one characteristic and one gene
40
how is a allele combination created
one trait cross
41
what is an example of one trait cross
FF x Ff
42
what are punnet squares
the use of a grid or matrix to diagram crosses between individuals by using the possible parental gametes
43
what is the purpose of punnet squares
to figure the probability that an offspring will have a particular genotype and phenotype
44
what is a monohybrid cross
a punnet square that includes one trait
45
what is a dihybrid cross
a punnet square that includes two trait
46
what is complete dominance
dominant allele produces a functional protein which has apparent effects; recessive allele produces a less functional protein and has no apparent effects
47
what are the three categories dominance
complete dominance, codominance, incomplete dominance
48
what is codominance
both alleles produce functional proteins and effects of both alleles are apparent in the heterozygous phenotype
49
what is incomplete dominance
the expression of a trait in a heterozygous individual is somewhere between expression of the trait in a homozygous dominant individual and the expression of the trait in a homozygous recessive individual
50
what is an example of incomplete dominance
a red rose and a white rose, the next rose would be pink
51
what is an example of codominance
a red fish and a blue fish would create a red spotted blue fish
52
what is albinism
the inability to produce melanin
53
what causes codominance
it occurs when the allels are equally expressed in a heterozygotes
54
what blood type alleles are codominant
A and B
55
what blood type alleles are recessive
O
56
what is a phenotype example of incomplete dominance
sickle cell allele
57
what is incomplete dominance
expression of the trait in a heterozygous individual is in between the way the trait is expressed in homozygous dominant or homozygous recessive person
58
what does the allele for sickling hemoglobin produce
an aboral form of hemoglobin that is less efficient in binding oxygen
59
what are polygenic traits
traits that are often non discrete or continuous aka quantitative traits
60
what is an example of a polygenic trait
height
61
what are pleiotropy traits
one gene that contributes to multiple traits
62
what is a multifactorial trait
a polygenic trait that is also influence by the environment
63
what are examples of multifactorial traits
skin color, and tanning
64
what is x-linked inheritance
the allele is carried on the x chromosome
65
what is y-linked inheritance
the allele is carried on the Y chromosome
66
TRUE OR FALSE: most sex-linked traits are Y-linked
FALSE it is x linked
67
TRUE OR FALSE: most sex linked trait are not related to sexual characteristics
TRUE
68
what is color blindness
most often characterized by red-green color blindness
69
what is muscular dystrophy
characterized by wasting of muscles and death by age 20
70
what is hemophilia
characterized by the absence of particular clotting factors that causes blood to clot very slowly or not at all
71
who are X linked traits and disorders found in
males
72
why are X linked disorders more often found in males
because recessive alleles are always expressed and males can only be homozygous for x linked alleles
73
what is mutation
a heritable change in DNA sequence
74
what time can mutations occur
any time
75
what are the two types of mutations
gremline and somatic
76
what are genetic disorders
disease causing alleles autosomal recessive
77
what is tay-sachs disease
lack of the enzyme that breaks down lipids in cell lysosomes resulting in lipid excess and eventually death in infants
78
what is cystic fibrosis
ion channel defect, so Cl- ions do not pass normal through a cell membrane resulting in thick mucus in lungs and other places often causing infections
79
what is phenylketonuria (PKU)
lack of an enzyme needed to make a certain amino acid (tyrosine) and affects nervous system development
80
what is sickle cell disease
red blood cells are sickle shaped (rather than biconcave) clogging blood vessels and are less efficient at carrying oxygen
81
what is Huntington disease
huntington protein has too many glutamine amino acids leading to the progressive degeneration of brain cells
82
what is Marfan syndrome
a genetic disorder that affects the connective tissue. mainly affects the skeletal, cardiovascular and ocular systems
83
what does DNA stand for
deoxyribonucleic acid
84
what is DNA
double stranded molecule twisted to form a double helix
85
what is a nucleotide consist of
one sugar, one phosphate, one nitrogenous base
86
what are the pairs in a nucleotide
A and T and C and G
87
how does DNA go to RNA
transcription
88
how does RNA go to protein
translation
89
how does DNA replicate
the parental molecule unwinds and unzips,
both parental strands serve as templates for new strands,
free nucleotides link to complementary bases on each DNA strand
90
what is the function of DNA polymerases
to link sugars and phosphates
91
what is DNA polymerases
a protein and an enzyme
92
how does DNA direct cellular activities
DNA codes for RNA, which codes for proteins, and proteins play structural or functional roles in cells
93
how is a gene expressed
when the protein it codes for is produced
94
what is RNA
single stranded polymers
95
what makes up RNA
nucleotides
96
what's the backbone of RNA
ribose and suer-phosphate
97
what are the bases in RNA
A,C,G and U
98
what are the three main types of RNA
mRNA, tRNA, and rRNA
99
what is mRNA
messenger RNA
100
what is the function of mRNA
carries genetic information from DNA to the ribosomes
101
what is rRNA
ribosomal RNA
102
what is the function of rRNA
joins with proteins to form ribosomes
103
what is tRNA
transfer RNA
104
what is the function of tRNA
transfers amino acids to a ribosomes where they are linked together to make polypeptides or proteins
105
what are ribozymes
enzymatic RNAs
106
what is snoRNA
components of mRMA splicing machinery
107
what is miRNA
microRNAs that regulate gene expressions
108
what are the two main steps of gene expression
transcription and translation
109
what is transcription
DNA is read to make mRNA in the nucleus of our cells
110
what is used to make mRNA
RNA polymerase
111
what is translation
reading the mRNA to make a protein in the cytoplasm on the ribosomes
112
what are the three steps of transcription
DNA unwinds, RNA nucleotides pair with DNA bases and are linked together, The RNA transcript is released from the DNA
113
what is introns
intervening sequences
114
what are exons
expressed sequences
115
what modifications to mRNA are made before it leaves the nucleus
removal of introns
116
what is the role of exons
to direct protein synthesis
117
what does codon mean
"words" in the genetic code
118
what are the stop codes for genes
UAA, UGA, and UAG
119
what is the start code for genes
AUG
120
what is the function of anticodon
binds to codon on MRNA, following complementary base pairing rules
121
what is the function amino acid attachment sites
the bind to a specific amino acid
122
what is the structure of ribosomes
two subunits, each composed of ribosomal RNA (rRNA) and protein
123
what is the function of ribosomes
bring tRNA bearing an amino acid close enough to mRNA to interact
124
what is the initiation stage of translation
major players in protein synthesis come together
125
what is the elongation stage of translation
occurs as enzymes in the ribosome link the amino acids, forming a growing chain of amino acids
126
what is the termination stage of translation
occurs when a stop codon moves into the ribosome
127
what is the molecular definition of a gene
a genes the entire nucleic acid sequence that is necessary for the synthesis of a functional polypeptide
128
what do active genes produce
specific proteins that determine the structure and function of a particular cell
129
what is heterochromatin
tightly packed chromatin which is not actively transcribed
130
what is euchromatin
loosely packed chromatin, which is accessible by transcription enzymes
131
what is epigenetics
the study of heritable changes in gene function which are not controlled by changes in the DNA sequence
132
what are mechanisms of epigenetics
DNA methylation, histone modifications, chromatin folding
133
what is an example of epigenetic change
a woman who smokes while pregnant induces epigenetic changes in three generations at once, in herself, her unborn daughter, and her daughter's reproductive cells
