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Biology: Genetics > Chapter 2: Mitosis and Meosis > Flashcards

Chapter 2: Mitosis and Meosis Flashcards

TO learn lol!

1
Q

The Nucleus is

A

-Found in eukaryotes
-Membrane-bound
-Houses genetic material (DNA)

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2
Q

Nucleolus

A

-Where ribosomal RNA (rRNA) is synthesized

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3
Q

-Nucleolus organizer region (NOR)

A

DNA that encodes rRNA

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4
Q

Nucleoid

A

-Found in prokaryotes
-NOT membrane bound

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5
Q

Cytoplasm includes:

A

-Nuclear cellular organelles are contained here

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6
Q

Cytosol

A

Colloidal material surrounding organelles

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7
Q

Cytoskeleton

A

Made of extensive system of tubules and filaments. Includes:
-Microtubules
-Microfilaments

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8
Q

Microtubules:

A

Made up of the protein tubulin

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9
Q

Microfilaments

A

Derived from the protein actin

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10
Q

Endoplasmic Reticulum

A

An organelle that:
-compartmentalizes cytoplasm
-increases the surface area for biochemical synthesis

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11
Q

Smooth Endoplasmic Reticulum

A

Site of fatty acid and phospholipid synthesis

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12
Q

Rough Endoplasmic Reticulum

A

Rough is studded with ribosomes
-Site of protein synthesis

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13
Q

Mitochondria

A

Within plant and animal cells
-Site of OXIDATIVE phases of cellular respiration, which generate ATP

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14
Q

Chloroplasts

A

Contained in plants, algae, protozoans
-Site of photosynthesis

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15
Q

Centrioles (ONE OF THE TWO LITTLE CUTE THINGS IN THE CENTROSOME)

A

-Found in the centrosome (the region, or the the cute little paired thingies involved in mitosis)
-Organize spindle fibers for movement of chromosomes during meiosis and mitosis
-Made of MICROTUBULES
-(inside of every cell) come to ends of cells and microtubules pulls the cells apart

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16
Q

Chromosomes exist as ___________ ______ in diploid organisms

A

HOMOLOGOUS PAIRS

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17
Q

Homologous chromosomes

A

-Similar, but not identical (different versions of the same gene)
- Carry genes for the same inherited characteristics
-May carry different versions of the same gene

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18
Q

Alleles

A

Different versions of the same gene

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19
Q

Centromere

A

-Constricted regions on chromosomes
-Location of centromere established appearance of chromosome

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20
Q

Different locations of the centromere, establishing the appearance of the chromosome:

A

-Metacentric: centromere is positioned in the middle
-Submetacentric: Slightly above the middle
-Acrocentric: Above the middle line
-Telocentric: Centromere is literally located on the top, forming an upside-down “c” shape

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21
Q

Sister chromatids

A

Draw a line vertically down the middle of homologous chromosomes, and you get the sister chromatids

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22
Q

Long arm on sister chromatid

A

q Arm

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23
Q

Short arm on sister chromatid

A

p arm

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24
Q

Somatic Cells

A

the regular body cells that have homologous pairs of chromosomes

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25
Humans have ___ chromosomes, meaning they have ___ homologous pairs
46 23 Represents the diploid number, 2n
26
Karyotype
Illustrates the physical a[[earance of the differnet pairs of homolougous chromosomes *Remember the matching up activity in bio lab?!*
27
Meiosis converts the diploid numner (2n) of chromosomes to the ________
haploid number (n) Note: n is the number of chromosomes
28
Genome
genetic information in the haploid set
29
Locus
Homologous chromosomes contain identical gene sites along their lengths Each site is called a locus
30
Biparental inheritance
inheritance from two parents (diploid organisms contain two copies of each gene)
31
Alleles
alternative forms of the same gene
32
Sex-determining chromosomes
NOT homologous Behave as homologs in meiosis Ex. X and Y
33
Zygote
single-celled fertilized egg of multicellular organisms
34
Karyokinesis
genetic material partitioned to daughter cells during nuclear division
35
Cytokinesis
Cytoplasmic division
36
Cell cycle
composed of interphase and mitosis
37
Interphase (brief summary)
S phase: DNA is synthesized Two gap phases: (G1 and G2)
38
Seperate phase that is part of interphase
G0 phase: point within G1 phase where cells are nondividing, but at a metabolically active state Cancer cells do NOT have a G0 phase
39
Interphase
characterized by the absence of visible chromosomes -Chromosomes are generally extended and uncoiled, forming chromatin
40
Mitosis has 5 discrete stages:
-Prophase -Prometaphase -Metaphase -Anaphase -Telophase
41
Prophase
Centrioles divide, move, and establish poles Nuclear envelope breaks down Chromosomes condense and become visible
42
Sister chromatids in the Prophase
Sister chromatids: the two parts of each chromosome Connected at the centromere Held together by a multi-subunit protein complex called coheSIN
43
Prometaphase
Period of chromosome movement to equatorial plane of the cell Centrioles reached the poles Spindle fiber forms
44
Equatorial plane
METAPHASE PLATE
45
Metaphase
Chromosome configuration following migration Centromeres align on the metphase plate
46
Kinetochore
Proteins associated with centromere Spindle fibers bind to kinetochore; chromosomes migrate
47
Kinetechore microtubules
Have one end near the centrosome region (the two little paired thingies) and the other anchored to the kinetochore
48
Cohesin
Protein complex that holds sister chromatids together
49
Separase
Enzyme that degrades cohesin
50
Shugoshin
Protein that protects cohesin from being degraded by separase
51
Anaphase
AKA disjunction Sister chromatids seperate and are now called DAUGHTER CHROMOSOMES -Migrate to opposite poles by shortening the spindle fibers -Motor proteins or molecular motors use ATP
52
Telophase
-Cytokinesis takes place -Uncoiling of the chromosomes takes place -reformation of the nuclear envelope -Spindle fibers disappear -Nuclear envelope reforms
53
Cytokinesis
Two new cells are produced
54
Cytokinesis in Plant cells
-a CELL PLATE is synthesized and laid down across the metaphase plate -Becomes the MIDDLE LAMELLA
55
Middle Lamella
a layer that cements together the primary cell walls of two adjoining plant cells.
56
Cytokinesis in animal cells
a constriction of the cytoplasm or cell furrow
57
Mitosis (brief summary)
Partitions chromosomes into dividing cells Produces daughter cells with a FULL diploid complement of chromosomes
58
CELL CYCLE REGULATION AND CHECKPOINTS
Mutations are known to exert an effect on the cell cycle
59
Cell division cycle mutations (cdc) mutaions
related to enzymes called kinases
60
Kinases
Can add phosphates to other proteins to regulate the cell cycle -an enzyme that catalyses the transfer of a phosphate group from ATP to a specified molecule. -Known as the MASTER CONTROL molecules functioning in conjunction with cyclin proteins
61
Cell cycle checkpoints
monitor mitosis for errors
62
Meiosis: reduction of genetic content and chromosomes
Reduces genetic material by half -Produces haploid gametes or spores, each containing one member of a homologous pair of chromosomes
63
Crossing over
A meiotic event in which there is a genetic exchange between members of homologous pairs of of chromosomes
64
Over view of Meiosis
Meiosis I: Reductional division Meiosis II: Equatorial division DNA synthesis (during interphase): before the beginning of meiosis I Does not occur again before Meiosis II
65
Meiosis I and II
each have a prophase, metaphase, anaphase, and telophase
66
Disjunction
Cause of genetic disease... Occurs during meiosis I or II sister chromatids aren't seperated from each other, even through they should be
67
Meiosis I: Prophase I
FIVE substages, each with specific events: -Leptonema -Zygonema -pachynema -Diplonema -diakinesis ENd of prophase I: centromeres are present on the equatorial plate
68
Chromomeres
Kinda compact DNA
69
Bivalent
homologous chromosomes
70
Tetrad
total of 4 homologous chromosomes
71
Chiasma
a point in which the two homologous chromosomes are in contact with each other Afterwards is terminalization
72
Substages of Prophase I: Leptonema
Chromosomes appear as long, single threads, unassociated with each other
73
Substages of Prophase I: Zygonema
-Synapsis: pairing of two chromosomes -Each pair of homologous chromosomes is known as bivalent (four chromatids) -Tetrad: number of chromatids (four chromatids)
74
Synapsis
pairing of two chromosomes (four chromatids)
75
Substages of Prophase I: Pachynnema
Each bivalent becomes shorter, thicker, and splits into two sister chromatids called tetrads -Crossing over occurs here: the exchange of genetic material between nonsister chromatids
76
Terminalization
A process that occurs after corssing over in meisis. -The chaismata move towards the ends of chromosomes This helsps the homologous chromosomes seperate during cell division
77
Which phase does crossing over occur in?
Prophase I, Pachynnema
78
Terminalization doesnt occur in a specific stage of meiosis
79
Substages of Prophase I: Diplonema
Within tetrads, sister chromatids seperate Chiasma: Wherae chromatids are still intertwined (think of crossing over)
80
Substages of Prophase I: Diakinesis
Nuclues and nuclear envelope break down Centromeres attach to spindle fibers
81
Meiosis I: Metaphase I
Chromosomes are at maximum shortness
82
Meiosis I: Metaphase I (TERMINAL CHIASMATA)
These hold nonsister chromatids together Binding to spindle fibers moves chromatids to metaphase plate
83
Chiasma
the point of contact between two chromatids belonging to two homologous chromosomes
84
Meiosis I: Anaphase I
Cohesion is degreaded between sister chromatids Homologous chromosomes seperate Nondisjunction may occur (failure of sister chromatids to separate)
85
Meiosis I: Telophase I
Cytokinesis takes place Two haploid cells result Nuclear membrane forms Nuclei enter interphase
86
How many cells and what type of cells form after meiosis I?
Two haploid cells
87
SUMMARY OF METAPHASE I, ANAPHASE I, AND TELOPHASE I
-homologous chromosomes seperate and move toward the poles -Sister chromatids remain attached at centromeres -Duplicated chromosomes reach the poles. each pole has a haploid set of chromosomes -cytokinesis: two haploid daughter cells are formed -nuclear envelope forms around the chromosomes in some species
88
Sister chromatids are c shaped
like??? wow.
89
Crossing Over produces genetic variation
Meiosis significatnly increases the level of genetic variation due to crossing over
90
Does duplication occur in both Meiosis I and II?
No, it only occurs in Meiosis I
91
Prophase II
each dyad is composed of one pair of sister chromatids attached by the centromeric region
92
Dyad
a Pair of sister chromatids
93
Metaphase II
The centromeres are positioned on the equatorial plate
94
Anaphase II
sister chromatids are sperated to opposite poles -Each haploid daughter cell from meiosis II has one member of each pair of homologous chromosomes
95
Telophase II
one member of each pair of homologous chromosomes present at each pole -Each chromosome is now a MONAD
96
Cytokinesis in Meiosis
Results in 4 haploid cells
97
Development of gametes differs between spermatogeneisis and oogenesis
Male gametes: produces by spermatogenesis in the testes Female gametes: produced by oogenesis in the ovary
98
Oogenesis
Formation of ova in the ovaries Four daughter cells do not revcieve equal cytoplasm Only one daughter cell recieves cytoplasm (PRIMARY POLAR BODY) Develops into ovum
99
Meiosis is critcal for successful sexual reproduction Plant and fungi life cycles
Fungi: haploid vegetative cells arise via meiosis-- proliferate via mitotic cell division Plants: life cycle alternates between diploid sporophyte stage and haploid gametophyte stage
100
Electron Microscopy
Chromosomes are only visible only during mitosis and meiosis Chromatin fibers that make up chromosomes coil and condense Folded-fiber model:
101

Biology: Genetics (7 decks)

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