Chapter 4a - Chromosomal Basis of Heredity Flashcards
1
Q
no. of chromosomes in prokaryotes
A
single chromosome + plasmids
2
Q
no. of chromosomes in eukaryotes
A
many chromosomes
3
Q
shape of chromosomes in prokaryotes
A
circular chromosome
4
Q
shape of chromosomes in eukaryotes
A
linear chromosomes
5
Q
component of chromosomes in prokaryotes
A
DNA
6
Q
component of chromosomes in eukaryotes
A
chromatin, a nucleoprotein (DNA coiled around histone proteins)
7
Q
location of chromosomes in prokaryotes
A
cytoplasm
8
Q
location of chromosomes in eukaryotes
A
nucleus
9
Q
duplication of chromosomes in prokaryotes
A
copies its chromosomes and divides immediately afterwards
10
Q
duplication of chromosomes in eukaryotes
A
- copies chromosome
- cell grows
- goes through mitosis to organize chromosomes into 2 equal groups
11
Q
chromosomes in eukaryotes during cell division
A
condensed and visible
12
Q
at the beginning of mitosis, eukaryotic chromosomes can be seen to consist of what
A
two threads (sister chromatids) joined by a centromere
13
Q
specific region of the eukaryotic chromosome where the kinetochore attach and pull the chromosomes during both mitosis and meiosis
A
centromere
14
Q
complex of DNA and proteins to which the spindle fibers attach
A
kinetochore
15
Q
Centromeric positions
A
- metacentric
- submetacentric
- acrocentric
- telocentric
16
Q
centromere is median
A
metacentric
17
Q
centromere is submedian
A
submetacentric
18
Q
centromere is subterminal
A
acrocentric
19
Q
centromere is terminal
A
telocentric
20
Q
parts of chromosome
A
- p (upper)
- q (bottom)
21
Q
ends of chromosome
A
GT rich repetitive sequences
22
Q
shortens with age
A
telomere length
23
Q
role of telomere
A
protects end of chromosome from deterioration
24
Q
cell aging
A
senescence
25
cell death
apoptosis
26
telomere and cancer
do not shorten
27
sequence of telomere
TTAGGG (500-3000 times)
28
- constant for each cell in the body (except sex cells)
- constant throughout the life of an individual
- constant for all members of a species
chromosome number
29
Cell Division stages
1. Interphase
2. Prophase
3. Metaphase
4. Anaphase
5. Telophase
6. Cytokinesis
30
3 stages of Interphase
1. G1 phase
2. S phase
3. G2 phase
31
cells carry out metabolic activities to prepare for S phase
G1 phase
32
DNA is replicated
S Phase (synthesis phase)
33
- organelles and molecules required for cell division are produced
- cell prepares for mitosis
G2 phase
34
G0 phase
cell cycle arrest
35
G1 phase
cellular contents, excluding chromosomes, are duplicated
36
S phase
each of 46 chromosomes is duplicated
37
G2 phase
cell "double checks" the duplicated chromosome for error, making any needed repairs
38
- results in the production of two daughter cells from a single parent cell
- the daughter cells are identical to one another and to the original parent cell
mitosis
39
organize spindle fibers that extend from the cell poles (polar fibers) and fibers that attach to chromosomes at their kinetochores
Asters
40
- chromosome condenses into chromatids
- spindle fibers emerge from centrosomes
- nuclear envelope breaks down
- nucleolus disappears
prophase
41
- nuclear membrane break down into numerous small vesicles
- as a result, the spindle microtubules now have direct access to the genetic material of the cell
prometaphase
42
- mitotic spindle is fully deveoped, and centrosomes are at opposite poles of the cell
- chromosomes line up
- each sister chromatid is attached to a spindle fiber originating from opposite poles
metaphase
43
- cohesion protein binding sister chromatids together break down
- sister chromatids (now chromosomes) pull toward opposite poles
- non-kinetochore spindle fibers lengthed, elongating the cell
anaphase
44
- chromosomes arrive at opposite poles and begin to condense
- nuclear envelope material surrounds each set of chromosomes
- mitotic spindle breaks down
telophase
45
separation of cytoplasm into two new daughter cells
cytokinesis
46
region in animal cells where proteins pinch in the center of the cell until it separates into two
cleavage furrow
47
region in plant cells where new cell wall components lay down in the center of the cell
cell plate
48
- results in the production of germ (sex) cells
- halves the number of chromosomes
- picks one chromosome from each pair at random and places them in a sex cell
- results in enormous variation amongst sex cells
meiosis
49
what is resulted from meiosis
enormous variation amongst sex cells
50
Meiosis I
reductional division
51
Meiosis II
equational division
52
Meiosis I stages
1. Prophase I
2. Metaphase I
3. Anaphase I
4. Telophase I
53
Substages of Prophase I
1. Leptotene/ Leptonema
2. Zygotene/ Zygonema
3. Pachytene/ Pachynema
4. Diplotene/ Diplonema
5. Diakinesis
54
longest duration
Prophase I
55
- beginning of prophase
- chromosomes can't be distinguished
- condensation of chromosomes begins
leptotene/ leptonema
56
zygonema word is from..
Greek words "paired threads"
57
- occurs as the chromosome approximately line up with each other into homologous chromosomes
- combined homologous chromosomes are said to be bivalent
zygotene
58
what are combined homologous chromosomes called
bivalent
59
- homologous chromosomes become much more closely related
- synapsed chromosomes may undergo crossing over
- chromosomes continue to condense
pachytene/ pachynema
60
process where homologous chromosomes become much more closely related
synapses
61
synapsed homologous pair of chromosomes
tetrad
62
- homologous chromosomes separate from one another a little
- chromosomes themseles uncoil a bit, allowing some transcription of DNA
diplotene/ diplonema
63
diplonema Greek workds meaning
two threads
64
- chromosomes condense further
- first point in meiosis where the four parts of the tetrads are actualy visible
- homologous chromosomes separate further, and the chiasmata terminalize making it clearly visible
diakinesis
65
point at which paired chromosomes remain in contact during the first metaphase of meiosis, and at which crossing over and exchange of genetic material occur between the strands
chiasmata
66
homologous pairs of chromosomes align on either side of the equatorial plate
metaphase I
67
spindle fibers contract and pull the homologous pairs, each with two chromatids, away from each other and toward each pole of the cell.
anaphase I
68
chromosomes are enclosed in nuclei
telophase I
69
protein lattice that resembles railroad tracks and connects paired homologous chromosomes in most meiotic systems
synaptonemal complex (SC)
70
meiosis II:
- chromosomes condense and the nuclear envelope breaks down, if needed
- centrosomes move apart, the spindle forms between them, and the spindle microtubules begin to capture chromosomes
prophase II
71
meiosis II:
chromosomes line up individually along the metaphase plate
metaphase II
72
meiosis II:
sister chromatids separate and are pulled towards opposite poles of the cell.
anaphase II
73
meiosis II:
nuclear membranes form around each set of chromosomes, and the chromosomes decondense
telophase II
74
the X-0 system
- 22+ XX (female)
- 22+ X (male)
75
the Z-W system
- 76+ ZW (female)
- 76+ ZZ (male)
76
the haplo-diploid system
- 32 (diploid) (female)
- 16 (haploid) (male)
77
sex determination in different animals
1. X-0 system
2. Z-W system
3. haplo-diploids system
