Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCB 10 > Lecture 16 > Flashcards

Lecture 16 Flashcards

1
Q

how can karyotype be abnormal? (two ways)

A

1) in chromosome number
2) in chromosome structure

-abnormal chromosome account for at least 50% of spontaneous abortions

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

polyploidy

A

extra chromosome sets

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

polyploid - tripoloid (3N)

A

cells have three sets of chromosomes

-accounts for 17% of all spontaneous abortions and 3% of stillbirths and newborn deaths

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

how are triploids produced (2 ways)

A
  • fertilization of one egg by two sperm

- fusion of haploid and diploid gametes

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

euploid

A

a normal chromosome number

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

aneuploidy

A

cells with extra (trisomy) or missing chromosomes (monosomy)

-most autosomal aneuploids are spontaneously aborted

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

nondisjunction

A
  • the failure of chromosomes to separate normally during meiosis
  • produces gamete with an extra chromosome and another with one missing chromosome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

nondisjunction during meiosis I

A

results in copies of both homolog in one gamete

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

nondisjunction during meiosis II

A

results in both sister chromatids in one gamete

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

what happens when aneuploidy arises during mitosis?

A

Aneupoidy produces groups of somatic cells with the extra or missing chromosomes

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

mosaic

A

an individual with two chomosomally-distinct cell populations

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

mitotic nondisjunction event

A

event that occurs early in development can have serious effects on the health of the individual

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

trisomies

A

most autosomal aneuploids cease developing as embryos or fetuses

  • seen in newborns = chromosomes 21, 18 13
  • carry fewer genes than other autosomes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

trisomy 21

A
  • down syndrome
  • most common among newborns
  • distinctive facial and physical problems
  • more likely to develop leukemia
  • like with one form of AD
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

turner syndrome

A

XO syndrome

  • 1 in 2,500 female births
  • 99% of affected fetuses die in utero
  • features: short stature, webbing at back of neck, incomplete sexual development (infertile), impaired hearing
  • individuals who are mosaics may have children
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

triplo-X

A

XXX syndrome

  • 1 in 1,000 female births
  • few modest effects on phenotype include tallness, menstrual irregularities, a slight impact on intelligence
  • X-inactivation of two X chromosomes occurs and cells have two barr bodies
  • may compensate for presence of extra X
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Klineffelter Syndome

A 
XXY syndrome (most common cause of male infertility)
-1 in 500 male births
phenotype include:
-incomplete sexual development
-rudimentary testes and prostate
-long limbs, large hands and feet
-breast tissue development
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

XYY syndrome

A

Jacobs syndrome

  • 1 in 1,000 male births
  • 96% are phenotypically normal
  • modest phenotypes may include great height, acne, speech and reading disabilities
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the most common cause of male infertility?

A

XXY or Klineffelter Syndrome

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

Deletions

A
  • A deletion refers to a missing genetic segment from a chromosome
  • Larger deletions increase the likelihood that there will be an associated phenotype
  • Cri-du-chat (cat cry) syndrome - Deletion 5p–
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Are deletions and dublications inherited?

A

no. Rather they arise de novo

22
Q

duplications

A

-refers to the presence of an extra genetic segment on a chromsome
-The effect of duplications on the
phenotype is generally dependent on their size
- Larger duplications tend to have an effect, while smaller ones do not

23
Q

duplications in chromosome 15

A 
poor muscle tone
epicanthal folds
small size
mental retardations
seizures
developmental delay
curved spine
learning disabilities
autistic features
24
Q

what is translocations and what is the two major types

A

two nonhomologous chromosome exchange segments

1) Robertsonian translocation
2) reciprocal translocation

25
Q

Robertsonian Translocations

A

two nonhomologous acrocentric chromosome break at the centromere and their long arms fuse

  • the short arms are often lost
  • affects 1 in 1,000 people
26
Q

translocation carriers (robertsonian translocations)

A

produce unbalanced gametes

-have 45 chromosomes

27
Q

translocation down syndrome

A

About 5% of Down syndrome results from Robertsonian translocation between chromosomes 21 and 14

-more risk of spontaneous abortion

28
Q

what happens when one of the parents is a translocation carrier?

A
  • they may have no symptoms

- however, the distribution of the unusual chromosome leads to various imbalances

29
Q

reciprocal translocations

A

two nonhomologous chromosomes exchange parts

  • about 1 in 500 people are carriers. Are usually healthy because they have the normal amount of genetic material (but it is rearranged)
  • However, if the translocation breakpoint interrupts a gene, there may be an associated phenotype
30
Q

Inversions

A

an inversion is a chromosome segment that is flipped in orientation

  • 5-10% cause health problems probably due to disruption of genes at the breakpoints
    1) paracentric inversion
    2) pericentric inversion

-inversions may impact meiotic segregations

31
Q

paracentric inversion

A

inverted region does NOT include centromere

32
Q

pericentric inversion

A

inverted region includes centromere

33
Q

isochromosomes

A

chromosomes with identical arms

-form when centromeres divide along the incorrect plane during meiosis

34
Q

ring chromosomes

A
  • occur in 1 in 25,000 conceptions
  • may arise when telomeres are lost and sticky chromosome ends fuse
  • genes can be lost or disrupted causing symptoms
35
Q

uniparental disomy

A

inheritance of two chromosomes or chromosome parts from the same parent

36
Q

what two rare events do unmiparental disomy (UPD) require?

A

the simultaneous occurrence of:

1) nondisjunction of the same chromosome in both sperm and egg
2) trisomy followed by chromosome loss

37
Q

pathogens

A

protection from harmful organisms

-based upon the ability to identify foreign molecules as “nonself”

38
Q

Foreign

A

bacteria, viruses, fungi, tumor, or transplanted cells

39
Q

antigens

A

molecules recognized by the immune system

-usually protein fragments or carbohydrates

40
Q

how do genes affect immunity

A

by conferring susceptibility or resistance to infection

41
Q

genetic control of immunity

A

a few types of single genes encode antibodies and cytokines that directly attack foreign antigens

genes also specify the cell surface antigens that mark the body’s cells as “self”

42
Q

what do mutations that impair immunity cause?

A

immune deficiencies
autoimmune disorders
allergies
cancer

43
Q

where is major histocompatibility complex found?

A

found on short arm of chromosome 6

  • includes about 70 genes
  • code for cell protein surface features
44
Q

major histocompatibility complex functional groups (3)

A
  • Class III genes - encode plasma proteins that carry out non-specific immune functions
  • Class I and II genes - encode human leukocyte antigens (HLA)
45
Q

Human leukocyte antigens (HLA)

A

link sugars to form branched glycoproteins that extend form cell surfaces

46
Q

antigen processing

A

process where human leukocyte antigens (HLA) glycoproteins can recognize bacterial and viral proteins, marking them fro immune system to target

47
Q

which classes of major histocompatibility functional groups encode human leukocyte antigens?

A

Class I and II:

  • Class I - found on all cell types. Class I HLA encode antigens defining “self”
  • Class 2: found mostly on antigen-presenting cells
48
Q

antigen-presenting cells

A

cells that bind antigens with HLA glycoporteins

49
Q

what are the two main types of antigen-presenting cells?

A 
machrophages
t cells (or T-lymphocytes)
50
Q

steps of antigen-presenting cells

A
  1. phagocytosis of the microbial invader
  2. antigens from the dismantled invader are attached to MHC self proteins
  3. MHC proteins and their attached antigens are displayed on machrophage surface
  4. helper T cells recognize antigens and MHC proteins and bind to the macrophage, initiating a series of immune events

MCB 10 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions