Brainscape's Knowledge GenomeTM

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


See full index

BIO 1A03 > Theme 5 > Flashcards

Theme 5 Flashcards

1
Q

DNA polymorphisms

A

1 or 2 alternate forms (alleles) at a chromosomal region that differs in either a single nucleotide base or have variable numbers of tandem repeats (VNTRs) in a given population of individuals

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

DNA markers

A

on a genetic map, are DNA polymorphisms that occur in non-coding DNA
- detectable by microarray analysis, PCR, southern blot techniques or DNA sequencing

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

SNPs

A

Single Nucleotide Polymorphisms

  • variations brought on by single nucleotide base pair substitutions in DNA that occur in a significant portion of a population
  • one of the most common types of genetic variation, scattered throughout the genome
  • when found close to a gene, used as markers for finding a particular gene
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

detecting SNPs

A

genotyping microarray is used
- loading wells with:
C, G, A, T - they will match one strand of one allele of the SNP
and X, Y - deliberate mismatches adjacent to SNP
- 2 possible alleles are tested for and whichever wells they base pair in will fluoresce (the well will)
note: electrophoresis is not an option because a change in SNP won’t change bp length

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

tandem repeats

A

patterns of 1 or more nucleotides that are repeated directly adjacent to another, found in various lengths in individuals across a population
- results in the variations observed between species

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

detecting VNTRs

A

using PCR and gel electrophoresis

  • tandem repeats are targeted and amplified with primers specific to flanking regions
  • bands that migrate the least distance are larger and therefore contain a greater number of VNTR copies
  • used in DNA profiling (DNA fingerprinting) but is extremely unlikely that any unrelated individuals would have the same VNTRs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

genotype

A

a representation of the pair of alleles carried by a person

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

phenotype

A

the cell or body’s interpretation of the genotype

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

sickle cell anemia phenotype

A
  • sickle shaped cells that don’t carry oxygen properly and lead to anemia
  • sickle cells can also block capillaries and cause acute pain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

HbA / HbA genotype results for beta-globin

A

phenotype: regular RBC are produced
- no symptoms of sickle cell anemia
homozygous genotype for HbA alleles
- codes for AA glutamine

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

HbS / HbS genotype results for beta-globin

A

phenotype: symptoms of sickle cell anemia
- no functional beta-globin proteins
homozygous genotype for HbS alleles
- amino acid produced is valine instead of glutamine, causing altered tertiary 3D structure that has decreased oxygen binding ability and aggregation causes RBC to have sickle shape

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

HbA / HbS genotype results for beta-globin

A

heterozygous genotype, 2 alleles are different (1 from each parent)

phenotype: no symptoms of sickle cell anemia, though cells exhibit both protein variants (both glutamine and valine)
- enough of the normal beta-globin to give us normal enough Hb to carry oxygen properly

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

beta-globin variations in populations around the world

A
  • across nations with the highest prevalence of sickle cell anemia, it’s been found that there are 5 possible distinct B-globin haplotypes found across patients that correlate to each region with sickle cell anemia SNPs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

individuals heterozygous for sickle cell allele

A

have a protective effect against malaria, a selective advantage

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

variation in gene copy number (CNV)

A
  • a region of a chromosome that may be duplicated or deleted compared to the normal amount of copies present
  • can occur in coding and non-coding regions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

CNV detection

A

copy number variations detected based on fluorescence intensities during DNA microarray analysis where more fluorescence means there are more copy numbers

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

the effect of gene copy number on phenotype

A
  • variations are thought to be a direct result of selective pressures such as an advantage to digesting more starch if you have a greater copy number
    ex. AMY1 copy number is higher in individuals with a historically high starch diet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

sequence polymorphism vs. length polymorphism

A

sequence: changes the message with one nucleotide
length: ex. tandem repeats - useful in paternity testing

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

linked SNPs

A

don’t necessarily cause a change but are close enough to a coding region that it gets copied with the genome

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

causative SNPs

A

affect the way a protein functions, correlating with a disease
ex. in an intron (indirectly) or an exon (directly) because exons code for genetic material

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

using PCR to detect VNTR differences in paternity testing

A
  • need to look at many VNTRs to be sure

- when neither fragment matches the father, the child is likely someone else’s

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

meiosis

A

replication of gametes which are haploid rather than diploid

  • has 2 rounds
  • allows production of offspring that are not genetically identical
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

prophase 1

A
  • homologous chromosomes condense and undergo synapsis

- final product is recombinant chromatids

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

recombination

A

a process that occurs in prophase 1

- involves the crossing over of homologous chromosomes and results in genetic variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

synapsis

A

pairing and physical connection of homologous chromosomes during prophase 1 via synaptromeal complex which holds the homologous chromosomes together during synapsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

sister chromatids vs. homologous chromosomes

A

sister chromatids: a pair of chromosomes that have been duplicated

homologous chromosomes: are individual chromosomes inherited from each parent and could be different

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

crossing over

A

exchange of corresponding segments of DNA b/w homologous chromosome pairs

  • occurs at x-shaped regions called chiasmata
  • increases genetic diversity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

chiasmata

A

where 2 homologous chromosomes physically cross over to exchange DNA segments during prophase 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

reductional division

A

refers to meiosis 1
- called reductional division because of the reduction in chromosome number (each chromosome has 23 chromosomes by the end)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

equational division

A

refers to meiosis 2

  • called equational because parent cells start off with the same number of chromosomes as the gametes produced at the end of meiosis 2
  • possible because duplicated sister chromatids gets separated
  • more similar to mitosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

dominant trait

A

the ones that appear in offspring of. cross b/w true breeding or homozygous parents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

anaphase 1

A

homologous chromosomes separate but sister chromatids do not separate
- synaptonemal complex breaks down to allow this

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

telophase 1

A

daughter cells are ready to move into prophase 2 when each half has a complete haploid cell of duplicated chromosomes (with each chromosome consisting of a pair of recombinant chromatids)
- at the end of telophase 1, nuclear envelope reforms, chromosomes slightly uncoil and cytokinesis follows to produce 2 separate cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

prophase 2

A

nuclear envelope breaks down and chromosomes condense

- spindle apparatus reforms

35
Q

anaphase 2

A

sister chromatids separate (they are NOT genetically identical because of crossing over)
- proteins holding sister chromatids together break down to allow separation

36
Q

non-disjunction

A

results in some gametes having extra chromosomes and other gametes having less chromosomes

  • leads to detrimental effects in generated offspring
  • can also occur in mitosis and be observed in cancer cells
37
Q

homozygous organisms

A

carried 2 identical alleles for a specific trait

38
Q

Gregor Mendel

A

characterized traits as dominant or recessive

- developed 2 laws: law of segregation and the law of independent assortment

39
Q

why is the blended model of inheritance not valid

A

because F1 offspring would be a blend of the 2 colours but instead they were reflective of the ratio of dominant to recessive

40
Q

Mendel’s 1st law of segregation

A

states that 2 alleles of a gene separate from each other into different gametes during gamete formation in both parents

  • based on the assumption that alternate versions of genes account for variations in inherited traits
  • if 2 alleles at a locus differ, then the dominant allele determines the organism’s final trait
  • attributed to separation of chromosomes during anaphase 1
41
Q

Punnett square

A

illustrates prediction of offspring b/w individuals of known traits

  • must consider possible gametes produced
  • practice one
42
Q

Mendel’s 2nd law of independent assortment

A

only applies to non homologous chromosomes, and genes/allele pairs found on different chromosomes

  • states that the segregation of one set of alleles of a gene pair is independent of the segregation of another set of alleles in a different gene pair
  • depends on alignment of homologous chromosomes at metaphase plate during metaphase 1
43
Q

monohybrids

A

organisms that are heterozygous for the trait produced by the cross

44
Q

nondisjunction in meiosis vs. mitosis

A

in meiosis - it affects the embryo which will affect the whole organism
- when homologous chromosomes do not separate during meiosis 1
- when sister chromatids do not separate during meiosis 2
in mitosis - it affects only a certain cell types but can result in a tumour

45
Q

meiosis in males vs females

A

it is less energetically costly for males and so they can reproduce throughout their lifetime

46
Q

the result of nondisjunction in meiosis

A
  • one gamete gets an extra copy of a chromosome while the other receives no copy
  • other chromosomes are distributed properly
  • mostly happens because of spindle checkpoint malfunctions
47
Q

aneuploid cells

A

have an abnormal number of chromosomes

48
Q

chromosomal abnormalities result in

A

40-50% of spontaneous abortions

49
Q

monosomy

A

having one less chromosome in a gamete that combines with a normal gamete (the gamete therefore contains 1 copy of that particular gene)

50
Q

trisomy

A

has 3 copies of a chromosome

- therefore 2 of the same kind will be present in a gamete

51
Q

mitotic arrested males

A

can also produce sperm cells with abnormal chromosome numbers (aneupoloidy)

52
Q

down syndrome

A

3 copies of chromosomes 21

  • affects 1/700 children
  • usually parents are older, from oocytes that have undergone nondisjunction
  • dev’tal challenges
  • usually live to be 50-60, and die from immune disorders or heart disease
53
Q

bioinformatic analysis

A

allows scientists to analyze proteins present in amniotic fluid that are characteristic of down syndrome development

54
Q

Dr. Brian Golding

A

looks at biology and math - computational biology

- looks at trisomy of chromosome 21 and has seen abnormal interactions b/w proteins

55
Q

Klinefelter syndrome

A

males with an extra X chromosome (genotype XXY)

  • most common aneuploidy in humans (1/500-1000 men)
  • can come from males or females,
  • men have more feminized structure, breast dev’t
  • autosomes are find but males generally produce less viable gametes
56
Q

Turner syndrome

A

monosomy of the X chromosome (most result in spontaneous abortions)
genotype XO
- less development and sterile, webbed neck
- 1/5000 births

57
Q

Caster Semenya

A
  • a female track star who had a hypersensitivity to androgen (hyperandrogenism) which lead to an uproar about gender testing in south african track and field association which probably ruined her career
  • this sucks because other platforms (NBA) look for performance enhancing polymorphisms (ex. being very tall)
58
Q

causal relationship b/w aneuploidy and tumourigenesis

A
  • mitotic chromosome instability is a feature of most cancer cells and it can lead to aneuploidy
    ex. males w breast cancer - have multiple copies of many chromosomes with lots of mismatching compared to healthy cells – this variation makes it hard to treat cancer cells
59
Q

weakened mitotic checkpoint

A

results in chromosome instability

ex. delay in splitting of chromosomes or one gets pulled away super quickly affecting many genes and causes aneuploidy
- Taxol is the drug that targets this and can stabilize microtubules against depolymerization so the cell remains in metaphase-anaphase and leads to apoptosis of cancer cells

60
Q

symbols on pedigree charts: what do they mean

A
  • single horizontal line - mating b/w individuals
  • vertical line - offspring from these people arranged horizontally L to R in order of birth
  • double line = mating b/w relatives
  • circles: female
  • squares: male
  • open symbol: not affected
  • filled in symbol: affected
  • lines running at a 45 degree angle to 2 people: twins
61
Q

sex chromosomes

A
  • the tips of the arms on the X and Y chromosomes shares a small region of homology and that’s where recombination can occur
  • almost none of the genes in the X chromosome have the same counterparts on the Y chromosome
  • X is much larger than Y
62
Q

explain how default is female

A

fathers can pass on an X or Y chromosome

- in humans, the presence of the Y chromosome sets off a cascade of events leading the development of the male phenotype

63
Q

Ishihara colour test

A

R/G colour blind test

- composed of dots with an internal pattern forming a number in red and green

64
Q

red-green colour blindness

A

an X-linked trait

  • women who are heterozygous are carriers and can pass the trait to offspring
  • any male receiving the recessive colour blind allele will be colourblind because they have only 1 locus for this
  • only women heterozygous for the colour blind allele will be colour blind
65
Q

carrier

A

heterozygous individuals that do not show the phenotype but can pass the affected allele to their offspring

66
Q

haemophilia

A

an X-linked recessive blood clotting disorder

- queen victoria was the first member of the royal fam to have it

67
Q

linked genes on the X-chromosome

A

there are about 1100 genes on it
P arm: short arm
Q arm: long arm
- the genes for colour blindness and haemophilia are linked (both on the end of the Q arm)

68
Q

linked genes

A

genes positioned close enough together on a chromosome (autosomes or X chromosomes) and tend to be inherited together and do not segregate independently

69
Q

are linked genes always inherited together?

A

no. linkage can be broken in prophase 1 of meiosis 1 when crossing over occurs, as a result, offspring may inherit only one of the genes due to the recombination effects that occur b/w linked genes

70
Q

recombination of alleles

A
  • the position of the genes does not change but the relative association of the alleles would change: this is caused by crossing over
  • alternately, if linked genes were immediately adjacent to one another, there would be no crossing over b/w the 2 genes: thus recombination of genes depends on the distance b/w them
71
Q

recombination frequency

A

is less when genes are close together

- can help us determine the distance between genes if we know the recombination frequency

72
Q

linkage map

A

shows the relative distance b/w genes on a chromosome

ex. genes for haemophilia and colour blindness are 12 map units apart (12million bp) - this distance is large enough for crossing over to occur b/w the 2 genes
- these are somewhat impractical for human applications so we use SNPs and markers to create high density linkage maps

73
Q

high density linkage maps

A

identify genetic loci that are only a few bp apart and they can map human genes that determine various characteristics
- still looks at the frequency of recombination

74
Q

genome wide association studies (GWAS)

A

looks across SNP linkage maps for an association b/w a phenotype and a SNP
- human SNP linkage maps: quicker and allow us to look at hundreds of thousands of people

75
Q

HMGA2 gene

A

an example of a GWAS

- found to contribute to less than 1 cm variation in height in humans

76
Q

cellular proteomes

A

can interact with one another based on the presence of membrane bound surface proteins

77
Q

ABO gene

A

the alleles we carry determine our blood type

  • the ABO locus has 3 main alleles: A, B, and O
  • an example of a variation that does not alter function
78
Q

A, B and O alleles on the ABO gene

A
  • A and B alleles code for a specific glycotransferase enzyme that catalyzes formation of A or B agglutinogens that are expressed on the cell surface
  • O alleles code for an inactive glycosyltransferase enzyme
  • the AB blood type has several SNPs that lead to formation of slightly different transferases
79
Q

HIV

A

human immunodeficiency virus

  • invades T cells by interacting with 2 surface proteins: T cell surface CD4 receptor protein and CCR5 co-receptor protein
  • once attached, the virus is engulfed by the cell and the infection begins, leading to the death of the T-cell and a compromised immune system
80
Q

CCR5 allele alteration

A

a mutation that allows T-cells to be immune to HIV infection

  • after mutation, a stop codon results from a frameshift mutation that produces an inactive CCR5 protein
  • this mutation in 14th century Europe prevented people from getting bubonic plague and so this mutation has been selected for by natural selection
81
Q

where do SNPs occur most often?

A

more are in non-coding regins than in coding regions

82
Q

Dr. David Meyre

A

Austin Solek is working under him

  • Dr. Meyre has a population genomics program and was part of the team that published the 1st GWAS in complex diseases (2007)
  • studies the genetic basis of obesity and T2D - found that there was a region of linkage on chromosome 6q and identified 7 loci contributing to adult obesity
  • discovered SIM1 gene responsible for a form of childhood obesity
  • identified that OGTT is a good indicator of T2D
83
Q

Dr. Ghulam Mufti

A

hopes to provide more into upon diagnosis of cancer

  • uses microarray analysis to identify all the genes that a person has and when cancer cells are added to the chip, the squares that light up should reveal a type of gene expression happening
  • this might be the start to customized medicine in terms of predicting how a patient’s cancer will behave
84
Q

DNA sequences variations in humans many determine how humans:

A

develop diseases

respond to drugs, pathogens, chemicals and vaccines

BIO 1A03 (6 decks)

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