Brainscape's Knowledge GenomeTM

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


See full index

biosci 101 > Genetics > Flashcards

Genetics Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards Psychology 101 flashcards Chemistry 101 flashcards Biology 101 flashcards Organic Chemistry 101 flashcards Sociology 101 flashcards
1
Q

What is the role of restriction enzymes?

A

They cut DNA at specific sequences
used as defines in bacteria as they cut phage dna
they cleave sugar phosphate bond in dna backbone in a staggered way

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

What is the role of DNA ligase?

A

sticky ends of dna are covalently bonded together on their sugar phosphate backbone

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

What is a cloning vector?

A

a DNA molecule that can carry foreign DNA

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

What are the characteristics of recombinant dna technology?

A

in vitro
can be between different species
alteration of host dna
and then reintroduction of altered dna into a living organism

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

What are the characteristics of biotechnology?

A

the manipulation of organisms or their components to make useful products

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

What are the three differences between genetic engineering and traditional biotechnology?

A

genetic engineering manipulates one or only a few genes at a time
Biotechnology produces new combos by manipulating thousands of genes at once

genes can be transferred from one species to another in genetic engineering but not in biotechnological breeding

genetic engineering allows for the editing of the DNA sequence of a single gene within the genome

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

How do they allow the bacteria to become competent for transformation?

A

Calcium and heat shock treatment OR Electroporation

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

Why is the restriction site placed in between the lac Z gene?

A

To identify whether the plasmid is a recombinant or not.
If it is recombinant, gene would be between lac Z gene, thus lac Z gene will be non functional and the colony would be colourless.
If it is not recombinant, lac Z gene is still functional and the colony will be blue as lac gene can break apart X-GAL (which is lactose attached to an indigo dye)

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

What is a reporter gene?

A

the antibiotic resistance gene, can differentiate bacterium with the plasmid and those without

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

What are the three steps to the PCR?

A

Denaturation
Annealing
Extension

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

What happens in the denaturation step?

A

DNA is heated to 95C

the two strands are separated

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

What happens in the annealing step?

A

temperature is reduced for annealing step

temperature is reduced for the primers to thatch to each dna strand

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

What happens in the extension step?

A

heated to 72C

heat stable dna polymerase created a complimentary strand

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

What are the three reagents required for the PCR reaction?

A

heat stable dna polymerase
deoxyribose nuceotides (dNTPs)
2 primers

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

What is the purpose of gel electrophoresis?

A

separates macromolecules (nucleic acids or proteins) on the basis of their movement through gel in an electrical field.

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

What does the rate of movement of a macromolecule in gel electrophoresis depend on?

A

size
electrical charge
and other physical properties

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

Is dna negatively or positively charged?

A

negatively

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

What is the difference between a genome and a transcriptome?

A

Genome - the total compliment of dna

transcriptome - part of a genome that is transcribed into mRNA

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

Explain dideoxy chain termination method

A

involves the synthesis of a complimentary strand of dna to that being sequenced.
synthesis is terminated un some of the molecules being synthesised by the addition of a fluroscently tagged dideoxyribonucleotide (ddNTPs) rather than a dNTP
There is a distinct fluorescent tag for each base (a c t g)
The resulting population of molecules is then separated by size with fluro labels detected for each fragment.
Read sequentially it gives the sequence of the snap on the original strand.

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

What is Genetic engineering?

A

the in vitro alteration or recombination of genetic material (DNA or RNA) and the reintroduction of the altered genetic material into a living organism.

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

What is needed for cloning genes?

A

(i) Restriction enzymes
(ii) DNA ligase
(iii) Cloning vectors
(iv) Host bacteria
(v) Gene transfer
(vi) Selectable markers

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

Can restriction enzymes produce both sticky and blunt ends?

A

yes

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

What is a Plasmid?

A

is a circular autonomously replicating DNA molecule which can replicate inside a host bacterial cell.

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

There are two types of selectable markers needed

A
  1. A marker to make sure that the bacterium has taken up the plasmid
    – Usually an antibiotic resistance gene
  2. A marker to make sure that the plasmid has an insert or foreign gene
    – Usually a marker that changes the colour of the bacterial colony on certain plates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

PCR is a

A

three step process that produces millions of copies of a targeted region of DNA
PCR is based on a heat stable DNA polymerase.
The polymerase generates the second strand of DNA from a single-stranded template.
DNA polymerases can only extend existing double- stranded regions and therefore require a primer.

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

Reagents in a PCR reaction:

A
  1. heat stable DNA polymerase
  2. deoxyribonucleotides (dNTPs)
  3. two primers (one for each strand)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Explain gel electrophoresis

A

Separates macromolecules (DNA or proteins) on the basis of their rate of movement through a gel in an electrical field – molecular sieve.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

in gel electrophoresis The rate of movement depends on

A

size, electrical charge, and other physical properties of the macromolecules.

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

Explain DNA sequencing

A

Reveals the order of nucleotides along a strand of DNA.

The Dideoxy Chain Termination Method involves synthesis of a complementary strand of DNA to that being sequenced

Synthesis is terminated in some of the molecules being synthesised by the addition of a fluorescently tagged dideoxyribonucleotide (ddNTP) rather than a dexoyribonucleotide (dNTP).

There is a distinct fluorescent tag for each type of nucleotide (A,C,G, and T).

The molecules are then separated by size and the fluorescent labels detected for each fragment

30
Q

Define Reproduction

A

is when an entity undergoes division that results in the production of two entities of the same kind.

31
Q

When does independent assortment occur?

A

At metaphase I, homologous pairs, each consisting of one maternal and one paternal chromosome, align in a random orientation.
Therefore each homologous pair assorts independently of the other chromosomes.
The number of possible combinations for n = 2 is 4 that is (2n).
However when n = 23 as in humans, 8 million combinations of chromosomes inherited from your mother and father (223) are possible.

32
Q

When does crossing over occur?

A

Crossing over occurs during prophase I.
Crossing over produces recombinant chromosomes, individual chromosomes carrying genes derived from two different parents.
Crossing over is the exchange of genetic material between non-sister chromatids.
In humans 1-3 crossover events occur per chromosome pair.
Shuffles the genes within the chromosomes.

33
Q

What are the four sources of genetic diversity in sexually reproducing organisms?

A

crossing over
independant assortment
random fertilisation
mutation

34
Q

Allele

A

alternative versions of a gene e.g. P or p

35
Q

Homozygous

A

an organism having a pair of identical alleles for a character e.g. pp

36
Q

Heterozygous

A

an organism having two different alleles for a character e.g. Pp

37
Q

Genotype

A

an organism’s genetic makeup e.g. PP, Pp or pp

38
Q

Phenotype

A

an organism’s expressed traits e.g. purple or white flowers

39
Q

3 ranges of interactions are known to occur between allelic forms of the same gene:

A

(i) completely dominant
(ii) incompletely (partially) dominant
(iii) co-dominant

40
Q

Complete dominance

A

an allele is dominant when the phenotypic effect is the same in both the heterozygous and homozygous conditions.

41
Q

incomplete or partial dominance

A

The dominant allele is not fully expressed in heterozygotes. The heterozygote has an intermediate phenotype.

42
Q

co dominance

A

Full expression of both alleles in the heterozygote. In humans that have the AB blood group both proteins are present & detected by immunological tests.

43
Q

polygenic inheritance

A

But for many characters such as height & skin colour the characters vary continuously – quantitative.
Quantitative characters indicate polygenic inheritance.
Polygenic inheritance - mode of inheritance in which the additive effect of two or more genes determines a single phenotypic character.
A single trait affected by a number of genes.

44
Q

How is human skin colour determined?

A

Evidence that skin colour in humans is controlled by at least three separate genes.
Lets consider three genes with a dark skin allele for each gene (A, B or C) contributing to the trait and being incompletely dominant to the other alleles a, b or c.
AABBCC person would be very dark while an aabbcc person would be very light.
Because the alleles have an additive effect AaBbCc and AABbcc would have the same skin colour because both have three units.

45
Q

what is the norms of reaction?

A

The norm of reaction is the phenotypic range for a given genotype in different environments.
Generally norms of reactions are broadest for polygenic characters.

46
Q

How do we look at genetic inheritance in humans?

A

pedigree analysis

47
Q

Explain Recombination of unlinked genes:

A

occurs by independent assortment.
50% recombinants are observed when genes are on different chromosomes or when genes are far apart on the same chromosome.

48
Q

Explain Recombination of linked genes:

A

occurs by crossing over during meiosis.
linked genes do not assort independently i.e. observe less than 50% recombinants; this is because genes are close together on the same chromosome.

49
Q

What is a barr body?

A

The inactivated X chromosome is called a Barr body.
Barr bodies are densely stained objects in the nuclei of females.
Most Barr body genes are not expressed.
Barr bodies are stable through mitosis but the
X is reactivated in the cells that give rise to ova.

50
Q

Inactivation of the X involves

A

modification of the DNA and histones, including the addition of methyl groups (–CH3) to nucleotides.
There are several genes located on the X chromosome that are involved in the inactivation process.
One gene XIST (X–inactive specific transcript) becomes active on the chromosome that will become the Barr body.
Multiple copies of the RNA product of the gene attach to the X chromosome, interaction between the RNA and chromosome initiates inactivation.

51
Q

Explain how Homologous chromosomes, or sister chromatids, fail to separate during meiosis.

A

May occur in meiosis I - homologous pair don’t separate.

May occur in meiosis II - chromatids don’t separate.

52
Q

Aneuploidy

A

abnormal number of certain chromosomes.

53
Q

Trisomic

A

1 extra chromosome (3 copies).

54
Q

Monosomic

A

1 less chromosome (1 copy).

55
Q

Nullisomic

A

lack both chromosomes (0 copies).

56
Q

Polyploidy

A

more than two complete chromosome sets e.g. triploid 3n and tetraploid 4n.

57
Q

What are the Alterations that can happen to chromosome structure

A

deletion
duplication
inversion
reciprocal translocation (crossing over in chromosomes that are non homologous)

58
Q

Down’s Syndrome

A

trisomy 21, incidence 1 in 700 children born in the United States.

59
Q

Turners syndrome

A

XO (phenotypically female but are sterile)

60
Q

Klinefelter’s syndrome

A

XXY
Individuals have male sex organs, are sterile and have abnormally small testes. Even though the extra X is inactivated, some breast enlargement & other female characteristics are common.

61
Q

Marker-assisted breeding involves the use of

A

molecular markers that are associated with a trait a breeder wishes to select for or against.
The molecular marker allows selection at the seedling stage rather than waiting 3 years for seedlings to grow into mature plants to distinguish the sexes.

62
Q

Metabarcoding involves the use of

A

PCR to amplify a region within a conserved gene followed by Next-Generation sequencing of the amplified fragments.

63
Q

Genetic Engineering

A

“The in vitro alteration or recombination of genetic material (DNA or RNA) and the re-introduction of the altered genetic material into a living organism”

64
Q

What is DNA fingerprinting?

A

In DNA fingerprinting the alleses are seperated form from one another through elctrophoresis which allows forensic scientist to compare the DNA fingerprints to other individuals making it possible to determine identification and parentage.

65
Q

why can recombinant frequencies NOT be greater than 50%?

A

If the recombinant frequencies were 50% it would equate to 50 map units in which the alleles would act as if they were on separate chromosomes. This does not occur therefore the recombinant frequencies can not be greater than 50% if the alleles are linked.

66
Q

The testcross described above resulted in the production of 850 parental-type offspring and 150 recombinant offspring. In the space below calculate the recombinant frequency between the locus that controls body colour (b) and wing size (vg).

A

RF= (150/1000)*100= 15%

67
Q

What is a centimorgan?

A

the distance between chromosome positions (also termed, loci or markers) for which the expected average number of intervening chromosomal crossovers in a single generation is 0.01.

68
Q

Assumed that crossing over occurs randomly then the frequency that crossing over occurs should be proportional to the

A

distance between two genes.

69
Q

A genetic map is

A

the order that loci occur along a chromosome.

70
Q

1 map unit =

A

1% recombinant frequency

71
Q

The observed recombination frequencies between three
fruit fly gene pairs are b-cn 9%, cn-vg 9.5%, & b-vg 17%.The b-vg recombination frequency is slightly less than the sum of the b-cn and cn-vg because

A

double crossing overs can occur reducing the recombination frequency.

72
Q

How does the human sense of smell work?

A

Each olfactory sensory neuron in our nose expresses a single olfactory receptor. All the neurons expressing the same receptor send axons to converge on a single glomerulus, which then has a single neuron (mitral cell) extending to the higher brain.

biosci 101 (6 decks)

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