Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Pathophysiology > Genes and Genetic Diseases > Flashcards

Genes and Genetic Diseases Flashcards

(111 cards)

Start Studying
1
Q

Genetics is the study of

A

biologic inheritance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

the substance that gives the nucleus a granular appearance

A

chromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

chromatin is observable in ___________ cells

A

non dividing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

just before the cell divides, the chromatin condenses to form discrete, dark-staining organelles, which are called

A

chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

With the rediscovery of Mendel’s important breeding experiments at the turn of the twentieth century, it soon became apparent that the chromosomes contained _____, the basic units of inheritance

A

genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The primary constituent of chromatin is

A

deoxyribonucleic acid (DNA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Genes are composed of

A

sequences of DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

By serving as the blueprints of proteins in the body, genes ultimately

A

influence all aspects of body structure and function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Estimates suggest that there are approximately ____________ genes.

A

20,000 to 25,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

An error in one of these genes often leads to

A

a recognizable genetic disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

To date, more than _____ genetic traits and diseases have be identified and cataloged.

A

20,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

As infectious diseases continue to be more effectively controlled, the proportion of beds in pediatric hospitals occupied by children with genetic diseases has

A

risen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

many common diseases that primarily affect adults, such as hypertension, coronary heart disease, diabetes, and cancer, are now known to

A

have important genetic components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

“gene therapy” is

A

the utilization of normal genes to correct genetic disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

each cell nucleus contains an identical __________ __ ___________

A

complement of chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

DNA is a double _____

A

helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

DNA is made up of these 3 basic components

A

five-carbon monosaccharide deoxyribose(sugar); a phosphate molecule; and four types of nitrogenous bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Two of the bases, ________ and _______ are single carbon-nitrogen rings called ___________

A

cytosine and thymine

PYRIMIDINES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The other two double carbon-nitrogen ring bases are called _______. Their names are _______ and _______.

A

PURINES

adenine and guanine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

the four bases are commonly represented by their first letter —-

A

ACTG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

the sides of the dna ladder consist of

A

deoxyribose and phosphate molecules (united by strong phosphodiester bonds)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

the rungs of the ladder are formed from

A

the nitrogenous bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

the base (rung) projecting from one side is bound to the base projecting from the other by a weak ________ bond

A

hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

which nitrogenous bases pair with eachother?

A

adenine—thymine

guanine—cytosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Each DNA subunit—consisting of one deoxyribose molecule, one phosphate group, and one base—is called
a nucleotide
26
dna directs the synthesis of all the body's
proteins
27
proteins are composed of one or more
polypeptides (intermediate protein compounds)
28
polypeptides in turn consist of
sequences of amino acids
29
the body contains __ different types of amino acids. they are specified by the _ ___________ _____
20 4 nitrogenous bases
30
To specify (code for) 20 different amino acids with only 4 bases, different combinations of bases, occurring in groups of 3, are used. These triplets of bases are known as
codons
31
the genetic code is 'universal'. what does this mean?
ALL living organisms use precisely the same DNA codes to specify proteins EXCEPT FOR MITOCHONDRIA - the cytoplasmic organelles in which cellular respiration takes place - they have their own extra nuclear DNA
32
each side of the DNA molecule consists of alternating
sugar and phosphate groups
33
the sequence of these nitrogenous pairs constitutes a genetic code that determines
the structure and function of a cell
34
The consistent pairing of adenine with thymine and of guanine with cytosine is known as _____________ ____ _______ and is the key to ________ ___________
complementary base pairing
35
a mutation is
any inherited alteration of genetic material
36
when one base pair replaces another, this type of mutation is called a
base pair substitution
37
base pair mutations may cause _______ or be ______ substitutions that do not change amino acids.
disease or be subtle
38
base pair mutations that DO NOT CHANGE THE AMINO ACID SEQUENCE and HAVE NO CONSEQUENCE are called
silent mutations
39
base pair mutations that do alter amino acids consist of two basic types:
missense and nonsense mutations
40
missense mutations produce a change in
a single amino acid
41
nonsense mutations produce
a stop codon in the messenger RNA (mRNA)
42
frameshift mutations result from
the ADDITION or DELETION of a number of bases THAT IS NOT A MULTIPLE OF THREE
43
a frameshift mutation alters
all of the codons downstream from the site of insertion of deletion
44
how many base pairs in a codon?
3
45
why are frameshift mutations called so?
they change the entire "reading frame"
46
why do "in-frame" insertions or deletions tend to have less severe disease consequences?
a multiple of three bases is inserted or lost
47
what are mutagens?
they are agents increase the frequency of mutations | radiation, mustard gas, formaldehyde etc
48
mutations are rare events. The rate of spontaneous mutations in humans is
10^-4 to 10^-7 per gene per generation
49
dna sequences that have particularly high mutation rates are called
mutational hot spots
50
DNA is formed and replicated in the
cell nucleus
51
protein synthesis takes place in the
ribosome
52
DNA code is transported from
nucleus to cytoplasm
53
protein is formed through two basic processes:
transcription and translation
54
transcription and translation are mediated by
ribonucleic acid (RNA)
55
a karyotype or karyogram is
an ordered display of chromosomes
56
A cell that does not contain a multiple of 23 chromosomes is
an aneuploid cell
57
Aneuploidy is usually the result of
nondisjunction
58
among live births, how many have a form of sex chromosome aneuploidy
about 1 in 500 males and 1 in 900 females
59
trisomy x effects
1 in 1000 newborn females
60
describe trisomy x
no overt physical abnormalities, although sterility, menstrual irregularity, or mental retardation is sometimes seen
61
in general, the more x chromosomes a female has the more
retardation tends to be present, along with various physical defects in those with 5 or more
62
sterile means
not able to produce children
63
Genetic diseases caused by single genes usually follow
autosomal dominant, autosomal recessive, or X-linked recessive modes of inheritance.
64
Pedigree charts are important tools in the
analysis of modes of inheritance
65
Recurrence risks specify
the probability that future offspring will inherit a genetic disease.
66
For single-gene diseases, recurrence risks remain
the same for each offspring, regardless of the number of affected or unaffected offspring.
67
The recurrence risk for autosomal dominant diseases is usually
50%
68
Germline mosaicism can alter recurrence risks for genetic diseases because
unaffected parents can produce multiple affected offspring
69
This situation in germline mosaicism occurs because
the germline of one parent is affected by a mutation but the parent's somatic cells are unaffected.
70
Skipped generations are not seen in
classic autosomal dominant pedigrees
71
Males and females are equally likely to exhibit _________ _______ _______ and to pass them on to their offspring
autosomal dominant diseases.
72
Many genetic diseases have a _______ age of onset.
delayed
73
A gene that is not always expressed phenotypically is said to have
incomplete penetrance
74
incomplete penetrance means
A gene that is not always expressed phenotypically is said to have
75
Variable expressivity is
a characteristic of many genetic diseases
76
Genomic imprinting, which is associated with ________, results in ______________________________________________________________________
methylation differing expression of a disease gene, depending on which parent transmitted the gene.
77
Epigenetics involves changes, such as
the METHYLATION of DNA bases, that do not alter the DNA sequence but can ALTER THE EXPRESSION OF GENES
78
Most commonly, parents of children with autosomal recessive diseases are
BOTH HETEROZYGOUS CARRIERS of the disease gene.
79
The recurrence risk for autosomal recessive diseases is
25%
80
When it comes to autosomal recessive diseases, males and females are
equally likely to be affected
81
Consanguinity is sometimes present in
families with autosomal recessive diseases
82
Consanguinity also becomes more prevalent with
rarer recessive diseases
83
Carrier detection tests for an increasing number of _________ _________ ________ are available.
autosomal recessive diseases
84
The frequency of genetic diseases approximately _______ in the offspring of first-cousin matings
DOUBLES
85
In each normal female somatic cell, one of the two X chromosomes is
inactivated early in embryogenesis
86
X inactivation is
random, fixed, and incomplete
87
X inactivation also may involve
METHYLATION
88
Gender is determined embryonically by the presence of
the SRY gene on the Y chromosome
89
Embryos that have a Y chromosome (and thus the SRY gene) become
males
90
Embryos that lack the Y chromosome become
females
91
When the Y chromosome lacks the SRY gene
an XY female can be produced
92
an X chromosome that contains the SRY gene can produce
an XX male
93
X-linked genes are those that are located on the
X chromosome
94
Nearly all known X-linked diseases are caused by
X-linked recessive genes
95
Males are __________ for genes on the X chromosome
hemizygous
96
X-linked recessive diseases are seen much more often in which sex? And why?
Males because they need only one copy of the gene to express the disease.
97
Fathers cannot pass ________ genes to their sons
X-linked
98
Skipped generations often are seen in X-linked recessive disease pedigrees because
the gene can be transmitted through carrier females
99
Recurrence risks for X-linked recessive diseases depend on
the carrier and affected status of the mother and father
100
A sex-limited trait is one that
occurs only in one sex (gender).
101
A sex-influenced trait is one that occurs
more often in one sex than in the other.
102
A marker locus, when closely linked to a disease-gene locus, can be used to
predict whether an individual will develop a genetic disease
103
A more complete gene map will facilitate
marker studies, gene cloning, studies of gene function and interaction, and gene therapy.
104
Traits that result from the combined effects of several loci are
polygenic
105
Multifactoral means
When environmental factors also influence the trait
106
Many multifactorial traits have a __________ __ _________ that once its crossed has been crossed, the disease may be expressed.
threshold of liability
107
What is used to estimate recurrence risks for multifactorial diseases?
Empirical risks - based on direct observation of large numbers of families
108
Recurrence risks for multifactorial diseases become higher if
more than one family member is affected or if the expression of the disease in the proband is more severe.
109
Recurrence risks for multifactorial diseases ________ _______ for more remote relatives.
decrease rapidly
110
The frequency of recombinations can be used to
infer the map distance between loci on the same chromosome
111
During meiosis I, _________ occurs and can cause ____________________________________________________
crossover recombinations of alleles located on the same chromosome.

Pathophysiology (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions