Lab Quiz 1 (Exer 1 pre) Flashcards
(115 cards)
1
Q
Genetics is the study of ____ and ____
A
Heredity and variation
2
Q
Transmission of traits from generation to generation
A
Heredity
3
Q
Deals with genetic differences between organisms
A
Variation
4
Q
Process involved in heredity and variation
A
Cell division
5
Q
All cells in all organisms grow and reproduce by
A
Cell division
6
Q
A unicellular bacterium, after ____, can reproduce by dividing into ____
A
Doubling its size; dividing into two cells
7
Q
In multicellular organisms, growth is attained by ______ or by ______
A
Dividing constituent cells; increasing size of preexisting cells
8
Q
Cell is growing and dividing; and the physical and metabolic activities of cells occur in a regular cycle in a repetitive manner
A
Cell cycle
9
Q
Two phases of cell cycle
A
Interphase and M-phase
10
Q
Non-dividing phase
A
Interphase
11
Q
Process in which a cell may double its entire content in preparation for cell division
A
Interphase
12
Q
Dividing phase
A
M-phase
13
Q
Where the cell contents are distributed into daughter cells
A
M-phase
14
Q
T/F: The amount of time spent in each phase of the cell cycle is a characteristic of a particular cell
A
T
15
Q
Phase: nucleus is very distinct; is enclosed by a definite nuclear membrane
A
Interphase
16
Q
One or several small round dense bodies within the nucleus
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Nucleoli
17
Q
Granular network of darkly staining material (in the nucleus)
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Chromatin
18
Q
Phase: consists of 3 phases that are not morphologically distinguishable; but biochemically distinct
A
Interphase
19
Q
3 Phases of interphase
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G1, S, G2
20
Q
Phase: Nucleus and Cytoplasm are enlarging toward mature size
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G1 Phase
21
Q
In G1, cell increases in volume by ___ and ____
A
imbibing water and nutrients; building new protoplasm
22
Q
In G1: what are the organelles formed?
A
Cytoplasmic organelles: ER, GA, ribosomes, mitochondria, chloroplasts
23
Q
In G1: what materials are produced?
A
Secretory and storage granules; cell wall materials
24
Q
In G1: if chromatin if stretched would resemble a?
A
Long chromatin fiber
25
Phase: active synthesis of DNA (replication) and histones
S phase
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Components of chromatin
Histones
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DNA content (C) of cell becomes ___ after replication
Doubled
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In S phase: Diploid cell with 2C will have ___ C after replication
4
29
In S phase: each chromatin fiber is _____
Replicated/doubled
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Phase: there is active synthesis of RNA and proteins necessary for chromosome synthesis
G2 phase
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Phase: mitotic spindles (spindle fibers are formed)
G2 phase
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In G2 phase: how is a chromosome formed
Doubled chromatin fiber is folded
33
Parts of a chromosome (5)
chromosome arm, chromatid, kinetochore, centromere, telomere
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Each chromosome is composed of
Sister chromatids
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Site of constriction of a chromosome
Centromere/ primary constriction
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Function of centromere
Attachment site of kinetochore proteins
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Site of attachment of spindle fibers
Kinetochores
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Tips of chromosomes
Telomeres
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Function of telomere
Stability
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Basis of chromosome classification
Position/location of centromere
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Centromere is median
Metacentric
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Centromere is submedian
Submetacentric
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Centromere is subterminal
Acrocentric
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Centromere is terminal
Telocentric
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A ____ may be associated in a secondary constriction
Nucleolus
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Presence of secondary constriction in a chromosome arm leads to ____
Formation of a satellite at the terminus
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Phase: may either be mitosis or meiosis
M-phase or division
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T/F: cell goes through interphase before undergoing division in both mitosis and meiosis
T
49
Undergone by all somatic/body and germ cells
Mitosis
50
In multicellular organisms, mitosis is a means of ___ and ____
Increasing number of cells; replacing worn out tissues
51
In unicellular organisms, mitosis is a ___
Mode of reproduction
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Number of set/s of chromosomes in a sexually reproducing diploid individual
Two sets (2n): 1 set (n) from male parent; 1 set (n) from female parent
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Complete set of chromosomes from either parent
Genome
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Each of the chromosomes in one set has a corresponding pair or ____ in the other set
Homologue
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Transmission of the chromosomes from parent to offspring
Union of gametes (n) via fertilization
56
Fertilization results in ___
Fertilized egg or zygote (2n)
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Each cell in zygote (2n) has ____ number of chromosomes as original zygote
The same
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Why are the number of chromosomes in each cell of offspring zygote same as number of chromosomes in each cell of parent zygote (chromosome constancy)
As cells divide, chromosomes are equally distributed among cells produced
59
Chromosome constancy is accomplished through ___
Mitosis
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Continuous orderly series of events wherein each cell divides to form two daughter cells that are exact replicas of the call from which they were derived (parent cell)
Mitosis
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Phases of mitosis (4)
Prophase, Metaphase, Anaphase, Telophase (PMAT)
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Phase: Chromosomes shorten, thicken, and become visible thick rods; they are longitudinally double with each half called a chromatid
Prophase
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Each half of a chromosome; closely pressed against each other throughout their length
Chromatids
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When do nucleoli and nuclear membrane completely disappear
Late prophase
65
T/F: After late prophase, spindle fibers radiate from microtubule organizing centers
T
66
Phase: Maximally condense chromosomes align at the equatorial plane
Metaphase
67
T/F: In metaphase, each chromosome separate from each other
F: Each chromosome separate from each other EXCEPT at the centromere
68
In metaphase, spindle fibers attach to the ________ on _____ sides of the centromere
Kinetochore proteins; opposite
69
Phase: Each chromatid of a chromosome as its own centromere
Anaphase
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At anaphase, centromeres become ____
Functionally double
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Phase: Each member of the doubled chromosome begins to move toward opposite poles
Anaphase
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What causes poleward movement in anaphase
Depolymerization of spindle fibers attached to the kinetochores at the centromere
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Phase: Upon reaching opposite poles, chromosomes regroup into nuclear regions
Telophase
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What happens to chromosomes after chromosomes regroup
They uncoil and lengthen and lose their visible identity
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What happens after chromosomes uncoil and lengthen
Cytokinesis / cytoplasmic division
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Phase: Sexually reproducing organisms reproduce by fertilization of their haploid (n) gametes
Meiosis
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In animal cells, cytokinesis occurs via ___
Cleavage furrow formation
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Cell wall plate formation starts from ___ towards ____
Inside, the periphery
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How is cytoplasm divided in plant cells
Via cell wall plate formation
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Cleavage furrow formation starts from ___ going ____
The periphery, inwards
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Most important feature of mitosis
Chromosome number remains constant through successive cell divisions
Chromosome duplication is followed by cell division; results to exact and equal distribution of chromosomes to each daughter cell
Chromosome makeup of daughter cells is the same as parent cell
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What makes mitosis an equational division
Chromosome makeup of daughter cells is the same as parent cell
80
Mature organisms produce gametes in the ____ of animals and ____ of plants
Gonads, sporangia (stamens and pistils)
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Meiosis occurs during _____, the process involved in gamete formation
Gametogenesis
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Gametogenesis in males
Spermatogenesis
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Gametogenesis in females
Oogenesis
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Gametogenesis in higher plants
microsporogenesis (males), megasporogenesis (females)
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Divisions consisting meiosis
Meiosis I and II
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AKA reductional division, involves separation of homologous chromosomes resulting in 2 cells each with haploid chromosome number
Meiosis I
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Equational division, second division, sister chromatids are separated, four haploid cells are produced
Meiosis II
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Explain names of 5 substages of Prophase I
first 4: reflects physical appearance of chromatin material in each stage
5th: reflects behavior of chromosomes in that stage
89
Describe Leptonema
- chromatin in nucleus appear as long thin threads w/ bead-like structures (chromomeres) along their lengths
- in some plants, chromosomes are clumped on one side of nucleus (synizesis)
- in some animals, drawn toward part of nuclear membrane close to centriole
-leptos = thin; nema = thread
90
Describe Zygonema
- synapsis begins (pairing of homologous chromosomes)
- synaptonemal complex is formed; this is essential for crossing over
- zygon = adjoining, nema = thread
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Essential for crossing over
Synaptonemal complex
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In zygonema, what do the paired chromosomes form
Bivalent (II) consisting of 4 chromatids
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T/F: Synapsis is precise and proceeds in a zipper-like fashion
T
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Describe Pachynema
- chromosomes are thicker due to further coiling
- chromosomes in a bivalent are closely appressed to each other
- chromatid breaks; repair occurs along the chromosome
- repair may entail crossing over
- pachus = thick, nema = thread
95
Describe crossing over
- exchange of segments between sister and non-sister chromatids in a bivalent
- cytologically observed through the formation of chiasma/chiasmata at the point of exchange
- generates further genetic variation (esp if between non-sister chromatids)
96
Prophase I stage: nucleolus is still evident, and chromosomes attached to it are called nuceolus organizers
Pachynema
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Describe Diplonema
- synaptonemal complex no longer functional
- longitudinal separation of homologues in a bivalent start from centromere toward both ends except at chiasmata
-diplo = two, nema = thread
98
Describe Diakinesis
- bivalents are maximally condensed and distributed throughout the nucleus
- terminalization of chiasmata between homologues that underwent crossing over, resulting in complete separation of homologues (may not easily be seen)
-at end:
1) nucleolus and nuclear membrane have disappeared
2) spindle fiber has formed
3) prophase i complete
- dia = across, kinesis = movement
99
Phase: bivalents align at equatorial plane, oriented such that homologues are on opposite sides of plan, with spindle fibers attached to their kinetochores
Metaphase I
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Phase: univalents (I), or homologues, in each bivalent separate from each other, univalents move to opposite poles
Anaphase I
101
In Anaphase I, what causes movement of univalents to opposite poles
Depolymerization of spindle fibers
102
In Anaphase I, what process accounts for the reductional phase of meiosis I
Homologues segregate from one another so that each anaphase group is composed of a haploid (n) number of chromosomes
103
Phase: chromosomes regroup and their coiled structures begin to relax; nuclear membrane and nucleolus reappear, forming two haploid daughter nuclei; cytokinesis follows
Telophase I
104
T/F: Cytokinesis takes place after meiosis I in all species
F; no, in some species it does not
105
Brief transitional stage occurring in telophase I before the cell proceeds to the next stage
Interkinesis
106
Phase: Chromosomes begin to condense, nuclear membrane disintegrates, nucleus disappears
Prophase II
107
Phase: Spindle fibers form, chromosomes align at equatorial plane
Metaphase II
108
Phase: Sister chromatids of a univalent separate and move to opposite poles as individual chromosomes
Anaphase II
109
Chromosomes uncoil and lengthen, nuclear membrane is reconstituted, nucleolus reappears; cytokinesis follows, forming 4 daughter cells w/ haploid chromosome numbers
Telophase II
110
Diploid starts with 2N chromosomes with 2X DNA content; ends with 2N chromosomes with 2X DNA content
Mitosis
111
A diploid cell starts with 2N chromosomes with 4X DNA content; ends with 4 haploid gametes with 1N chromosomes and 1X DNA content
Meiosis
112
