Brainscape's Knowledge GenomeTM

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


See full index

pathophysiology > lecture 3 > Flashcards

lecture 3 Flashcards

1
Q

aneuploidy

A

extra/ missing chromosome
(ex. trisomy 21 - downsyndrome)

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

phenotype

A

expressed traits derived from genotype

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

expression of genes

A
  • segments of DNA chains that determine cell properties (structure and function)
  • basic units of inheritance
  • exist in pairs/ alleles with one in each chromosome (locus)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

dominant gene

A

expressed in either homozygous or heterozygous state (Aa or AA) - brown eyes

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

recessive gene

A

expressed in only homozygous state (aa) - blue eyes

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

codominant gene

A

both alleles of a pair are equally expressed (blood type A/B)

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

sex-linked gene

A

genes carried on sex chromosomes, produce sex-linked traits (X or Y)

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

female carrier of recessive X-linked trait

A

normal

effect of defective allele is offset by normal allele on the other X-chromosome

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

male carrier of recessive X-linked trait

A

DEFECTIVE

X chromosome functions like a dominant gene (ex. hemophilia)

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

X chromosome inactivation (lyonization)

A
  • only 1 of the 2 X chromosomes in females is genetically active
  • 1 is inactivated around 16th day of embryonic development
  • barr body or sex chromatin body: inactive X chromosome
  • this happens so females with 2 X don’t overexpress X chromosome gene products
  • inactivated one is randomly chosen (remains inactive throughout lifetime of cell)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

chromosome analysis - karyotype

A
  • studies composition and abnormalities in chromosomes
  • number and structure
  • way to determine if someone has a full karyotype
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

method of karyotype analysis:

A

1- use human blood for cells and culture
2-fluorescent probes paint chromosomes
3- lymphocytes stimulated to undergo mitotic division
4- cell division stopped in metaphase and cells swell (so they can be visualized)
5- prepare stained smears of chromosomes
6- chromosomes arranged in pattern (karyotype)

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

structure of DNA

A

DNA helix –> wraps around histone to form chromatin fibre –> (in prophase) chromatin fibres coil tightly and condense to form densely packed chromosome

double coils of DNA with protein (wrapped around histone = nucleosome) beads on a string

packing of DNA into chromosomes - 10,000x!

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

structure of DNA - nucleotide

A

basic structural unit of DNA in chromosomes consisting of:

  • nitrogen-containing base:
    C-G
    T-A
    (purine bases: A,G)
    (pyridine bases: C,T, U)
    *uracil only in RNA
  • linked to deoxyribose (sugar)
  • phosphate group

*3billion C-G A-T pairs in genome
only 1-2% of DNA code for proteins

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

DNA replication - semi-conservative

A

both chains separate and act as templates for copies to form 2 new identical strands of DNA

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

non-coding regions

A

gene expression
- silencers, enhancers, promoters, tRNA, rRNA, telomeres

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

heterochromatic

A

tightly packed

centromeric regions are mostly non-coding (genes not usually expressed)

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

euchromatin

A

loosely packed

regions enriched for genes (genes expressed here)

*highest gene density observed in subtelomeric regions

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

exosomes

A

extracellular vesicles

  • REGULATES GENES
  • phospholipid bilayer, released by all cell types in various biological fluids and extracellular space
  • released through exocytic budding of plasma membrane response to cellular activation or apoptosis
  • key regulators in cell-to-cell communication
  • through cell-cell transfer of signalling proteins, transcriptional regulators, lipids and nucleic acids (DNA, RNA, mRNA, miRNA)
  • biomarkers to identify diseases
  • immune modulation, cancers, CVD, diabetes, neurodegenerative diseases (alzheimers), inflammatory disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

post-translational modifications

A

before proteins attain their normal structure or function, they undergo these by enzymes

  • modify a.a. side chains (hydroxylation, methylation)
  • addition of carbohydrate
  • proteolytic cleavage of polypeptides
  • localization sequences, results in transport to specific cellular locations or secretion from the cell
  • increases protein diversity: alters function, stability, binding, activity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

phenotype is derived from:

A

genome
transcriptome
proteome
interactome (interactions between molecules)
metabolome (metabolites and their interactions within a biological system)

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

epigenetics

A

how behaviors and environment can change gene expression (sequence not altered)

23
Q

chromosome disorders

A
  • defect from excess or deficiency of genes on entire chromosomes or segments
24
Q

single-gene defects

A

caused by pathogenic mutations in individual genes on both or one chromosome of a pair

often cause inheritance pattern diseases (autosomal recessive, autosomal dominant, X-linked)

25
Q

multifactorial disease

A

inheritance pattern, described majority of diseases in which there is genetic contribution
- no single error, result of combined impact, triggered by environmental factors
- we will experience this (alzheimers, diabetes, CAD)

26
Q

mitosis

A

2 daughter cells that are exact duplicated of parent cell

27
Q

meiosis

A

intermixing of genetic material between homologous chromosomes (chromosomes reduced by half)

28
Q

gametogenesis

A

process of forming gametes (mature germ cells)
- gonads (testes and ovaries): contain precursor cells called germ cells; capable of developing into mature sperm or ova

29
Q

spermatogenesis

A

development of sperm
- spermatogonia: precursor cells in the testicular tubes
- 4 formed from each precursor
- occurs continually, completed in 2 months

30
Q

oogenesis

A

development of ova
- oogonia: precursor cells
- 1 ovum formed from each precursor, others discarded as polar bodies
- not produced continually
- oocytes formed before birth, remain in prolonged prophase of first meiotic division until ovulation

31
Q

spermatogenesis process

A
  1. spermatogonia form primary spermatocytes (mitosis) -46
  2. (meiosis 1) secondary spermatocytes - 23
  3. (meiosis 2) spermatids
  4. sperm
32
Q

oogenesis process

A
  1. oogonia form primary oocytes (mitosis in ovaries) - 46
  2. (prophase of meiosis) - MONTHLY CYCLE primary follicles
  3. 1 dominant primary follicle matures via FSH-LH, 1 mature follicle ovulated each month
  4. (first meiotic division) - secondary oocyte when discharged from ovary
  5. (second meiotic division) - after mature ovum is fertilized
    *ovum only reach end of second division if one gets pregnant
33
Q

turner syndrome

A

45X

34
Q

triple X syndrome

A

47XXX

35
Q

kleinfelter syndrome

A

47XXY

36
Q

XYY syndrome

A

47XYY

37
Q

effect of extra Y

A

no significant effect

mainly carries genes concerned with male sexual differentiation

38
Q

effect of absent Y

A

body configuration is female

39
Q

effect of extra X in female

A

little effect because only one X is activated

40
Q

effect of extra X in male

A

ADVERSE effect on male development - overexpression

41
Q

downsyndrome

A

trisomy-21
- by nondisjunction or translocation
- most common chromosomal abnormality
- nondisjunction during gametogenesis (oogenesis)

*can also have mitotic non-disjunction early in embryogenesis - MOSAIC

42
Q

causes of aneuploidy

A
  • autosomal trisomy: nondisjunction during maternal meiotic division
  • maternal age: age of primary oocyte 50+years, exposure (failure to forming chiasmata)
  • almost all aneuploidy are from maternal bc ovum aging, but Y ones are paternal
  • risk increases with maternal age!!!
  • spermatozoa constantly dividing from puberty on
  • man 50+ may have mutations during all its divisions - DNA copy errors during mitosis
43
Q

achondriplasia

A
  • increase cases with PATERNAL AGE
  • FGFR 3 mutations (from so much division of spermatozoa)
  • autosomal dominant
  • most common cause of dwarfism
  • a number of associated health problems
44
Q

mosaicism

A
  • the presence of two or more cell lineages with different genotypes from single zygote
  • THIS CAN ALSO OCCUR FROM ACQUIRED MUTATION (nondisjunction during mitosis) - typically anaphase error
  • proportion of mosaicism will determine severity of disease
45
Q

genetically transmitted diseases

A

from abnormalities of individual genes on the chromosomes

chromosomes appear normal - inherited mutations

some defects arise spontaneously, others from environmental teratogens (physical effects to developing embryo)

46
Q

fragile X syndrome (X-linked mental deficiency)

A

INHERITED chromosomal abnormality

  • high number of CGG repears in DNA chains on FMR1 gene - expressed in neurons
  • 200+ repeats results in gene silencing (5-40 normal)
  • becomes more pronounced as it gets passed down generations
  • women pass it to daughters and sons (more common, more severe)
  • men pass it to daughters
47
Q

SNPs

A

structural variations in single gene nucleotides of different individuals

  • determination of genetic susceptibility to chronic diseases and cancer
  • some effect gene functions –> individual differences in body functions
    (how fast cell inactivated toxin or repairs DNA. Variations in responses to food, abx, drugs. ability to detoxify potential carcinogens or susceptibility to cancers)
48
Q

genetic disease

A

our genes determine susceptibility to ALL DISEASES (multifactorial inheritance)

most genetic disease is resistant to conventional treatment - symptomatic treatment (need future ability to modify gene expression)

49
Q

recombinant DNA technology

A

techniques used to manipulate how and where genes are expressed

  • ex. for increased understanding of genetic disease by studying normal gene structure and function
  • ex. for bacterial production of drugs/ abx

experimental models
- remove gene or add defective gene

50
Q

gene therapy

A

extension of principles of recombinant DNA technology

  • normal genes are inserted into a defective cell to compensate for missing/ dysfunctional gene
  • ex. CRISPR to edit genes

genes must be identified, cell type receive gene and delivery of vector considered and function of gene in system confirmed

alter genes or produce proteins

51
Q

translation of DNA into protein

A
  • DNA directs synthesis of proteins/ enzymes through ribosomes in cytoplasm
  • DNA for expressed genes transcribed into mRNA (complementary, single stranded copy of DNA)
  • premRNA further processed to remove non-coding regions (introns) and splicing remaining exons (coding)
  • mRNA is exported to ER to translate into proteins (ribosomes)
  • rRNA carries out protein synthesis on ribosomes
  • tRNA transfers a.a. in sequence (anticodon) according to mRNA codons to produce proteins
52
Q

where is the highest gene density observed

A

subtemoleric regions

53
Q

gene expression

A

massive impact - different cells/ same DNA

  • small fraction of genes expressed
  • 6% of genes expressed in all tissues (microarray), 30-40 genes expressed - tissue dependent
  • tightly regulated, constantly changing responding
  • layers of control
  • transcription (mRNA) - promoters, enhancers, activators, repressors
  • translation (protein) - initiation, elongation, termination
  • gene products can also further regulate other genes
    -mRNA/ protein degradation
54
Q
A

pathophysiology (10 decks)

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