Cellular and Molecular Genetics Flashcards

1
Q

what are 3 components of mendelian genetics?

A
  • selection and transmission of genes
  • dominance and gene expression
  • genotypic basis of phenotypic outcomes
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2
Q

what are 4 components of molecular and cellular genetics?

A
  • gene structure
  • DNA as a blueprint
  • DNA replication and error correction
  • the cell cycle and genetic recombination
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3
Q

what is a gene?

A
  • a region of DNA that controls a discrete hereditary characteristic, usually corresponding to a single protein or RNA.
  • this encompasses the entire functional unit, including coding DNA sequences, noncoding regulatory regions, and introns
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4
Q

DNA is organized into ___

A

chromosomes

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5
Q

the genome is constructed of ___ chromosomes.

A

46

44 autosomes (22 pairs) and 2 sex chromosomes (1 pair)

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6
Q

DNA to RNA describes what?

A

transcription

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7
Q

RNA to protein describes what?

A

translation

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8
Q

DNA is wrapped around ___ to form nucleosomes

A

histones

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9
Q

eukaryotic DNA exists in long ___ strands

A

linear

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10
Q

DNA in nucleosome form is called ___

A

chromatin

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11
Q

draw out the cell cycle

A
  • check points at the end of G1 and G2
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12
Q

what is LINE?

A
  • long interspersed nuclear elements
  • thought to be involved in gene silencing and regulation
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13
Q

what is SINE?

A
  • short interspersed nuclear elements
  • thought to be involved in gene silencing and regulation
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14
Q

during what phase is DNA replicated?

A

synthesis (S) phase

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15
Q

in the S phase, replication initiates at ___ origins, both DNA strands are ___, and DNA replication is ___

A
  • replication
    • replication bubbles are formed
    • replication occurs in both directions
  • templates
  • semiconservative
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16
Q

in the S phase, DNA replication is semiconservative. what does that mean?

A

each of the two strands from the original “parent” DNA double helix serve as templates for a new strand

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17
Q

DNA is synthesized at ____

A

replications forks

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18
Q

in eukaryotic replication fork synthesis, what makes up the primosome?

A

DNA helicase and DNA primase

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19
Q

what holds together two chromatids to make a chromosome?

A

the centromere

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20
Q

what does DNA polymerase do?

A

polymerizes new DNA strands

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21
Q

what does topoisomerase do?

A

places nicks in the DNA to relax coils

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22
Q

what does DNA primase do?

A

creates RNA primers on the lagging strand

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23
Q

DNA polymerase replicates DNA, and chain growth occurs in what direction?

A

5’ to 3’

so, all of the base pairs are added to the 3’ end

24
Q

what are the functions of polymerase alpha, beta, gamma, delta, and epsilon?

A
  • alpha - RNA and/or DNA primers
  • beta - base-excision repair
  • gamma - mitochondrial DNA replication and repair
  • delta - lagging-strand synthesis, DNA repair
  • epsilon - leading-strand synthesis
25
Q

what are 4 common DNA damages?

A
  • mismatch
  • deamination
  • depurination
  • double strand break
26
Q

eukaryotic cells divide by ___ and ___

A

mitosis and meiosis (in that order)

27
Q

draw out the mitosis phase

A
28
Q

draw out the meiosis phase

A
29
Q

the completion of interphase leads to ___

A

mitosis

30
Q

what 3 things happen during interphase?

A
  • the cell increases in size
  • DNA of the chromosomes is replicated
  • the centrosome is duplicated
31
Q

what happens in the G1, S, and G2 phases of the cell cycle?

A
  • G1 - protein synthesis, checkpoint
  • S - DNA replication
  • G2 - protein synthesis, checkpoint
32
Q

what occurs in the prophase step of mitosis?

A
  • chromosomes condense
  • mitotic spindle assembles
33
Q

what occurs in the prometaphase step of mitosis?

A
  • nuclear envelope breaks down
  • chromosomes attach to spindle via kinetocore, and undergo movement
34
Q

what occurs during the metaphase step of mitosis?

A
  • chromosomes align along the equator of the spindle between the poles
  • kinetocore microtubules attach sister chromatids to opposite poles of the spindle
35
Q

what occurs during the anaphase step of mitosis?

A
  • sister chromatids separate to form two daughter chromosomes which move toward opposite poles
  • kinetochore microtubules get shorter; spindle poles move apart
  • chromosome separation
36
Q

what occurs during the telophase step of mitosis?

A
  • daughter chromosomes arrive at spindle poles and decondense
  • nuclear envelope reassembles around individual chromosomes
  • cytoplasm division begins and contractile ring starts to form
37
Q

what occurs during the cytokinesis step of mitosis?

A
  • cytoplasm is divided in two by the contractile ring
    • actin and myosin filaments
  • contractile ring pinches the cell in two, creating two new daughter cells
38
Q

meiosis forms ___ gametes

A

haploid (1n)

39
Q

what are 4 characteristics of meiosis?

A
  • additional round of division
  • genetic reassortment
  • bivalents form during meiosis I
  • genetic recombination occurs within bivalents in meiosis I
40
Q

chromosome assortment increases ___

A

genetic diversity

41
Q

general recombination exchanges ___ and ___ genetic content

A

maternal and paternal

42
Q

recombination is directed by ___

A

recombinases

43
Q

diploid starting cell: two different chromosome assortment patterns

meiosis I yields how many diploid cells?

meiosis II yields how many haploid cells?

what does this describe?

A
  • 4
  • 8
  • independent assortment
44
Q

describe recombination

A
  • increases genetic diversity
  • maternal and paternal chromosomes cross over and swap genetic information
  • they then undergo independent assortment
45
Q

chromosome assortment increases genetic diversity in what two ways?

A

independent assortment and recombination

46
Q

general recombination occurs in bivalent chromosomes. what does this mean?

A
  • pairing of duplicated homologous chromosomes forms a bivalent
  • two kinetocores sit next to each other/ line up on the spindle
  • recombination occurs
  • genetic material is swapped
47
Q

transposable elements create ___

A

site-specific recombination

48
Q

what are the 3 classes of transposable elements?

A
  • DNA-only transposons
  • retroviral-like retrotransposons
  • nonretroviral retrotransposons
49
Q

age and genetic lineage can be traced by what?

A

identifying and locating transposons

50
Q

what is the general function of retroviral-like retrotransposons and nonretroviral retrotransposons?

A
  • produce RNA transcript, which is then put back into the genome as a DNA transcript
  • undergoes an RNA intermediate
51
Q

what is the cut-and-paste process of transposon insertion?

A

transposon is physically removed from DNA

52
Q

what is the viral insertion process of transposon insertion?

A

viral DNA attacks particular region, integrates it into that portion of the DNA

53
Q

what is the replication process of transposon insertion?

A
54
Q

how are recombined chromosomes segregated?

A
  • sister chromatids start to pull apart
    • meiotic metaphase I
  • arms of sister chromatids become unglued
    • meiotic anaphase I
  • brief interphase followed by m-phase with kinetochores functioning separately on each sister chromatid
    • meiotic metaphase II
  • sudden detachment of chromosomes (sister chromatids) at centromere
    • meiotic anaphase II

genetic structure is altered

55
Q

when are tetrads formed?

A

during metaphase I (meiosis I)