Chapter 11 Flashcards
1
Q
Cell Division
A
- Process of making 2 daughter cells
- both cells must have full complement of DNA present in parent cell
- Parent Cell must be large
- Key cellular components have to be duplicated before cell division takes place
1
Q
Mitotic Cell Division
A
- more complicated than binary fission
- genome much larger
- organized into one or more linear chromosomes
2
Q
2 stages of cell cycle
A
M Phase and Interphase
3
Q
Cytokinesis
A
Division of cell into 2 separate cells
4
Q
M Phase
A
- Goes through mitosis and cytokinesis
- 5 steps: Prophase, Prometaphase, Metaphase, Anaphase, Telophase
5
Q
Interphase
A
- Stage between 2 M phases
- makes many preparations for division
6
Q
3 stages of interphase
A
S, G1, and G2 phase
7
Q
G1 phase
A
- Between end of M phase and start of S phase
- when specific regulatory proteins are made and activated
- preparation for S phase
- enlarges cell
8
Q
G2 phase
A
- Between end of S phase and start of M phase
- size and protein content increase before division
- Checks all DNA that was produced
9
Q
G0 phase
A
- Pause between M phase and S phase
- absence of preparation for DNA synthesis
- performs specialized function
10
Q
Karyotype
A
-Portrait formed by number and shapes of chromosomes representative of a species
11
Q
Homologous Chromosomes
A
2 of the same type of chromosome- one from mother, one from father
12
Q
sex chromosomes
A
the X and Y chromosomes
13
Q
Ploidy
A
number of complete sets of chromosomes
14
Q
Haploid
A
one complete set of chromosomes
15
Q
Diploid
A
two complete sets of chromosomes
16
Q
Polypoid
A
More than two complete sets of chromosomes
17
Q
Sister Chromatids
A
- Two identical copies of DNA
- Do not separate
18
Q
Centromere
A
Constriction that holds sister chromatids together
19
Q
Prophase
A
- First stage of mitosis
- Characterized by appearance of visible chromosomes
- Centrosome duplicates and each one begins to migrate around the nucleus
- Final locations define where the cell will eventually be separated into 2 daughter cells
20
Q
Mitotic Spindle
A
- In the cytosol
- pulls chromosomes into separate daughter cells
21
Q
Centrosome
A
Compact structure that is the microtubule organizing center for animal cells
-Assembles mitotic spindle
22
Q
Prometaphase
A
- Nuclear envelope breaks down and the microtubules of the mitotic spindle attach to chromosomes
- Chromosomes are not organized
23
Q
Kinetochores
A
- 2 protein complexes associated with the centromere of each chromosome
- One on each side of constriction
24
Metaphase
- Microtubules lengthen or shorten
- Chromosomes aligned in the middle of dividing cell
- Most visually distinctive under microscope
- ensures efficient and complete separation of genetic info
25
Anaphase
- Sister chromatids separate
- Centromere divides to allow the sister chromatids to separate
- travel to opposite poles
26
Telophase
- Chromatids begin to revert back to chromatin
- Cytokinesis is initiated
- Nuclear envelopes re-form around each set of chromosomes creating 2 nuclei
- Marks the end of mitosis
27
Contractile Ring
- Ring of actin filaments that form against the inner face of the cell membrane
- Ring contracts pinching the cytoplasm of the cell, dividing it into 2
- driven by motor proteins
28
Phragmoplast
- formed from dividing plant cells
| - consists of overlapping microtubules that guide vesicles containing cell wall components to the middle of the cell
29
Cell Plate
- New cell wall in the middle of the dividing cell
| - Fuses with original cell wall once cell is large enough
30
Meiotic Cell Division
- Important in development of multicellular organisms and repair of tissue and organs
- produces gametes
- only occurs in specialized reproductive cells
- Has 2 rounds of cellular division
- Makes sexual reproduction possible
- Makes 4 daughter cells instead of 2
31
Prophase 1
- chromatids condense into chromosomes
- beginning of formation of mitotic spindle
- spindle fiber only able to connect to each chromosome once
- centrosomes begin to migrate
- nuclear envelope begins to break down
32
Synapsis
- homologous chromosomes pair with each other
- occurs in prophase 1
- forms bivalent
33
Bivalent
4 stranded structure created by synapsed chromosomes
34
Non-sister chromatids
- Chromatids attached to different centromeres
- Replicas of different chromosomes
- genetically similar but not identical
35
Chiasma
Crosslike structures within bivalent
36
Crossing Over
- physical breakage and reunion between non-sister chromatids
- allows maternal and paternal chromosomes to undergo an exchange of DNA segments
- creates allelic combinations that didn't exist before
37
Metaphase 1
-Meiotic spindle completed and bivalents move so that they lie on an imaginary plane
38
Anaphase 1
- 2 homologous chromosomes of each bivalent separate as they're pulled in opposite directions
- Centromeres/Sister Chromatids don't separate
39
Telophase 1
- cytoplasm divides producing 2 separate cells
| - No DNA synthesis between the 2 meiotic divisions
40
Prophase 2
- Chromosomes condense
| - Nuclear envelope disappears and spindle begins to set up
41
Metaphase 2
-Chromosomes line up so that centromeres lie on an imaginary plane cutting across the spindle
42
Anaphase 2
- Centromere of each chromosome splits
| - separated chromatids pulled toward opposite poles of the spindle
43
Telophase 2
-4 genetically unique gametes
44
Equational Division
Same number of chromosomes at the beginning and the end
45
Division of cytoplasm in female mammals
- cytoplasm divides unequally
| - most remains in very large cell called oocyte
46
Polar Bodies
smaller cytoplasm sites
47
Division of cytoplasm in male mammals
- divides equally
| - goes on to form functional sperm
48
2 processes of sexual reproduction
Meiosis and fertilization
49
Where human meiosis occurs
Female: ovaries Male: testes
50
zygote
- single cell formed by gametes fusing during fertilization
| - diploid
51
cyclin
- regulatory proteins that activate kinases
| - levels rise and fall with each turn of the cell cycle
52
Checkpoint
regulatory mechanism for cell cycle
53
DNA replication checkpoint
- At the end of G2
| - Checks to see if all DNA is replicated
54
DNA damage checkpoint
- Before entering S phase
| - Checks to see if the DNA is damaged
55
Spindle Assembly Checkpoint
- Before Anaphase
| - Checks to see if all chromosomes are attached to the spindle
56
Phospholtases
Removes phosphate group
57
Aromatic Amines
Organic chemicals that enter cells and associate with DNA
58
Chromosomes in Eukaryotes
- linear
- More of them than in Prokaryotes
- Isolated in nucleus
- Mitotic spindle assembled in the cytosol
- Packaged with histone proteins
59
Chromatin
- DNA coiled up around a histone protein
- Chromatin goes through condensation to make chromosomes
- Chromosomes only exist during division
60
Autosomes
- chromosomes 1-22
| - don't determine sex
61
Alleles
- Different forms that genes come in
| - All alleles same for homologous chromosomes and in the same location
62
Solutions to having so much DNA
- Package the DNA in pieces
- Replicate all the DNA before starting to segregate it
- Keep sister chromatids coupled until time for division
- Condense the length of each chromosome
- Develop a special machine to do segregation job
63
Mitosis
Separating genetic info in the cell to divide
64
Kinetochore
-special region that is on the outside of
the centromere where mitotic spindle attaches
-mitotic spindle attaches on each side of the centromere
65
2 things Meiosis has to have
- Has to produce haploid gametes
| - Has to introduce genetic variation
66
Genetic Variation
Involves crossing over and independent assortment
67
Replication Division in Meiosis 1
- 1 diploid cell into 2 haploid cells w/ replicated chromosomes
- Homologous chromosomes separate
68
Meiosis II
- sister chromatids separate
| - 4 haploid cells w/ unreplicated chromosomes
69
Recombinant Chromatids
New genetic combinations
70
Independent Assortment
How 1 bivalent lines up completely independent from other
71
3rd source of genetic variation
- From sexual reproduction
| - random fertilization
