Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

GIM > cytogentic basis of inheritance > Flashcards

cytogentic basis of inheritance Flashcards

1
Q

define cytogenetics

A

study of chromosomes within a cell.

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

what is conventional cytogenetic analysis

A

metaphase chromosome analysis (chromosomes are condensed and can be visible)
G banding

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

what is molecular cytogenetics

A

cytogenetics analysis at the molecular resolution at all stages of the cell cycle- DNA in situ.

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

examples of molecular cytogenetics

A
  • FISH
  • Microarray CGH
  • Next generation sequencing (NGS)
  • MLPA
  • QF-PCR
  • qPCR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How long does the cell cycle take

A

24hrs

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

what are the different stages in the cell cycle

A 
growth phase 1
synthesis
growth phase 2
mitosis
cytogenetics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how long is growth phase 1 of the cell cycle and what happens during this phase

A

6-12 hrs

cellular components are duplicated excluding chromosomes.

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

how long is the synthesis phase of the cell cycle and what happens during this phase

A

6-8 hrs

each of the 46 chromosomes is duplicated by the cells.

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

how long is growth phase 2 of the cell cycle and what happens during this phase

A

3-4 hrs

the cell double checks the duplicated chromosomes for errors and make needed repairs.

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

how long is mitosis

A

1 hr.

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

What are the stages of mitosis

A

Interphase, prophase, metaphase, anaphase, telophase and cyokinetics.

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

what happens in each stage of mitosis

IMPACT

A
  • Interphase- all chromosomes loose
  • Prophase- chromosome condense
  • Metaphase- chromosome (made of 2 chromatids)- line up along the midline.
  • Anaphase- the sister chromatids are separated
  • Telophase- the cell begins to split into 2
  • Cytokinesis- cell splits in 2 cells and chromosomes unwrap again.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In what stage of the cell cycle does G banding take place

A

metaphase.

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

How are chromosomes laid out on the template slide for G-banding.

A

line up chromosomes 1- 23, paired up and in order.

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

what are the main 2 types of cytogenetic abnormalities.

A

numerical

structural

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

what is the dosage effect

type of cytogenetic abnormality

A

gain or loss in chromosome number

loss is worse

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

How can a gene be disrupted

A

breakpoint, inappropriate activation/ inactivation.

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

define genomic imprinting

A

alleles from 1 parent are suspended.

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

what is the position effect on a gene

A

A gene in a new chromosomal environment functions inappropriately

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

what has a more severe phenotype sex chromosome imbalance or autosomal imbalance.

A

autosomal imbalance.

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

define anueploidy

A

gain (trisomy) or loss (monosomy) of chromosomes

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

define polyploidy

A

gain whole sets (triploidy or tetraploidy)

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

define mosacism

A

diploidy and anueploidy is one human genome.

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

where do numerical abnormalities arise ( in which stage of cell development)

A

gametogenesis (meiosis- most errors in female meiosis)
fertilisation
early cleavage (post zygotic non disjunction).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what factors increase the risk of numerical abnormalities in chromosomes during gametogenesis.
maternal age >35
26
what are the stages in meiosis.
``` prophase 1- DNA replicate Metaphase 1- chiasmta visible Anaphase 1- chromosome separation Telophase- cells begin to separate Cytokinesis- secondary gametocyte. Meiosis 2 - sister chromatics are pulled apart. ```
27
what is the most common meiotic error
non disjunction
28
when does chromosome disjunction occur in meiosis and what does it form
meiosis 1 2 disomic gametes ( which have twice the content of normal gametes) 2 nullisomic gametes ( no content)
29
when does chromatid disjunction occur in meiosis and what does it form
meiosis 2 | 1 disomic 1 nullisomic and 2 normal gametes.
30
most common 3 autosomal anueplodiues
Trisomy 21, trisomy 18 and trisomy 13.
31
what are the head abnormalities seen in a patient with trisomy 21
Eyes: upward slanting; brushfield spots (on iris) Nose: Small Ears: abnormally shaped/low set Tongue: protruding General – flat face, brachycephalic, short neck .
32
what percentage of children with trisomy 21 spontaneously abort
75%
33
what are the neurological abnormalities seen in a patient with trisomy 21.
Learning disabilities (mild to moderate IQ 30-60)
34
what are the hands and feet abnormalities seen in a patient with trisomy 21.
single palmar crease short broad hands 5 th finger clinodactyly- small finger. wide sandal gap.
35
what fertility problems do males and females with trisomy 21 face
females none. | males infertile.
36
what other conditions are individuals with trisomy 21 more prevalent to.
alzheimer's hypothroid obesity/ coeliac, arthritis, diabetes, hearing loss seizures.
37
what percentage of trimsomy 18 spontaneously abort
95%
38
what head abnormalities seen in a patient with trisomy 18.
microcephaly, low set ears, micrognathia (small jaw), cleft lip and palate
39
what are the hands and feet abnormalities seen in a patient with trisomy 18.
``` clenched hands (seen on scan) polydactyly overlapping fingers (rocker bottom feet). ```
40
what mental abnormalities seen in a patient with trisomy 18.
mental retartdation.
41
what organ malformation occurs in trisomy 18
umbilical and inguinal hernia congenital heart disease congenital kidney abnormality eye abnormality (cataracts and micropthalmia)
42
what percentage of trisomy 13 spontaneously abort
95%
43
what are mental abnormalities seen in a patient with trisomy 13.
Mental retardation severe Microcephaly/ sloping forehead Defects of brain – holoprosencephaly
44
What are the hand and feet abnormalities of trisomy 13
Polydactyly & fingers flexed
45
what are the head abnormalities of trisomy 13
Eyes – microphthalmia, coloboma, retinal dysplasia, palpebral fissures slanted Cleft lip and/or palate Ears abnormal and low Can have Cyclops
46
what other abnormalities of trisomy 13 are evident
Heart defect | Abnormal genitalia
47
what types of structures of the human body does trisomy 13 present with
midline structures are affected
48
How long do female eggs stay in meiosis 1
foetus 5 months until puberty
49
when do eggs go into meiosis 2
once they have been fertilised or bleed out in puberty.
50
what is age dependent deterioration of meiotic structures
long the eggs stay in meiosis 1 more likely the environment will impact them) - hormonal imbalance, irradiation, oral contraceptives, alcohol
51
Are sex chromosome anueploidies age dependent
no
52
Are autosomal anuplodies age dependent
Yes- maternal age.
53
give 2 examples of conditions which are sex chromosome anueplodiy
Turners (45 X) | Klinefelter. (47XXY)
54
What reproductive problems are faced with turners syndrome
Loss of ovarian function No puberty Infertility
55
what lymphatic problems do people with turners syndrome face
Webbed neck | Swelling of hands &/or feet
56
what other abnormalities do people with turners have
Skeletal Abnormalities – short stature Coarctation of aorta IQ generally normal/reduced compared to sibs
57
how is klinefelters diagnosed
infertility or hypogonadism.
58
what fertility problems do patients with klinfelters face.
``` lack secondary sexual characteristics Testicular dysgenesis (abnormal development. gynaecomastia ```
59
what growth problems do people with linfelters face
Normal in infants, then accelerates | Adults long legs and arms
60
What are the 2 main errors in fertilisation
1. Polyploidy (usually triploidy) | 2. Molar pregnancy (double paternal, no maternal)- no genetic content.
61
what percentage of triploides spontaneously abort
99.9%
62
define digmy
twice the genetic content in egg
63
define diplospermy
twice the genetic content in the sperm.
64
define dispermy
2 sperm fertilise 1 egg
65
what is the consequence of double maternal content
small placenta Macrocephaly - all available nutrients fo to the brain to ensure survival. significant grwoth delay.
66
what is the consequence of double paternal content
massive placenta | some growth delay
67
what does the maternal genome code for foetus or placenta
foetus
68
what does the paternal genome code for foetus or placenta
placenta
69
consequences of a molar pregnancy
Double paternal genome | Massive cystic placenta
70
define molar pregnancy
haploid sperm and empty egg results in haploid zygote
71
when does monocaism happen
post zygotically.
72
2 main types of chromosome rearrangements
Translocation | Inversion
73
2 types of translocations
reciprocal | robertsonian
74
2 types of inversions
pericentric | paracentric
75
what is reciprocal translocation
* Break and exchange | * Content is the same just rearranged
76
each type you break a chromosome what is the % chance that you will break a gene
3%
77
what is a robertsonian translocation
whole arm fusion
78
what chromosome undergo robertsonian translocation
acrocentrics-13,14,15,21,22
79
does the long q arm of short p arm contain DNA information
long q arm.
80
is there reproductive risk in robertsonin and reciprocal translocation
Yes
81
define pericentric inversion
breaks either side of centromeres
82
what is paracentric inversion
breaks on one side of the chromosome.
83
do inversion have a reproductive risk
Yes
84
In robertsonian tranlocations is the phenotype of the patient affected
No, all genetic material is still present | q ars fuse and p are lost (but p has no genetic information)
85
unbalanced rearrgaments can be caused by
CNV- copy number variation | Deletions and duplications
86
2 types of deletions
Interstitial | terminal
87
what is a interstitial deletion
segment lost from within the chromosome.
88
what is a terminal deletion
segment lost from the end of the chromosome.
89
what is worse a chromosome loss of duplication
loss
90
what causes the phenotype in deletions and duplications
abnormal gene dosage.
91
what causes deletions and duplications to occur
* Mediated by low copy repeats or duplications. * Defined regions of repetitive DNA * So when chromosome line up the similar regions can mismatch and pair together. * Chaismata occurs leading to deletion and duplication.
92
what causes variable clinical expression of deletions and duplications
variable size of imbalance, other genetic and environmental effects
93
what is a ring chromosome
terminal ends of a chromosome are detached and then it forms a ring structure (one end attaches to the other)

GIM (14 decks)

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