Ch. 6 & 7 Chromosomes, Mitosis, and Meiosis Flashcards
(96 cards)
1
Q
describe prophase I
A
-chromosomes become visible. -the nuclear envelope breaks down. -crossing over occurs
2
Q
What are homologous chromosomes?
A
chromosomes that are similar in size, shape and genetic content
3
Q
what is the process by which sperm are formed called?
A
spermatogenesis
4
Q
2 X and one Y means
A
klinefelters syndrome
5
Q
name the steps of binary fission.
A
- DNA is copied. 2. Cell begins to divide. 3. Cell completely divides. 4. Two identical haploid cells are created.
6
Q
What functions do spindles perform during mitosis?
A
they move chromosomes during mitosis
7
Q
What happens in inversion?
A
a chromosome fragment attches to the same chromosome but in reverse order
8
Q
what happens during the first growth (G1) phase of the cell cycle?
A
cell carries out its routine functions. It is normal and living
9
Q
What controls the cell cycle?
A
proteins
10
Q
Prokaryotes reproduce asexually by ____
A
binary fission
11
Q
what if the process by which eggs are formed called?
A
oogenesis
12
Q
describe anaphase II
A
-centromeres divide -chromatids move to opposite poles of the cell
13
Q
for the plant cell cell to undergo cytokinesis what must they do
A
form a cell plate
14
Q
What types of environmental influences can induce mutations?
A
chemicals, ultraviolet radiation, and viruses
15
Q
purpose of meiosis
A
make genetically unique gametes
16
Q
What is a homologous pair?
A
a pair of chromosomes
17
Q
what can you see in karyotypes?
A
homologous pairs, abnormalities, and sex
18
Q
What is a pair of chromosomes called?
A
a homologous pair
19
Q
describe metaphase I
A
pairs of homologous chromosomes move to the equator of the cell
20
Q
What spermatogenesis?
A
the formation of sperm
21
Q
what is meiosis?
A
the process of cell division that halves the number of chromosomes to form gametes
22
Q
What happens in crossing over?
A
paternal and maternal homologous chromosomes cross DNA
23
Q
How does prokaryotes reproduce?
A
asexually
24
Q
What are the two types of cells in your body?
A
gametes and somatic cells
25
What are the three mechanisms for genetic variation?
-Crossing over -Independent assortment -random fertilization
26
the first three stages of the cell cycle is called
interphase
27
What function do centrioles perform in animal cell mitosis?
they help form the spindle
28
What contains the information to make proteins that regulate cell growth and division
genes
29
when a sperm fertilizes an egg, what is formed?
a zygote
30
what is the cell cycle?
a repeating sequence of cellular growth and division during the life of an organism
31
when and where does oogenesis take place
in the ovaries of a women during fetal development
32
Purpose of mitosis
make identical copies of mother cell
33
what happens in duplication?
a chromosome fragment attaches to its homologous chromosome creating a duplicate of the gene in the fragment
34
What is a karyotype?
a picture of chromosomes from largest to smallest
35
describe prohase II
a new spindle forms around the chromosomes
36
The checkpoint that makes the decision whether the cell will divide is the
cell growth (G1) checkpoint
37
What is the 23rd pair of chromosome called?
sex chromosome
38
descibe telophase I and cytokinesis
-chromosomes gather at the poles of the cell -the cytoplasm divides
39
A zygote is haploid or diploid?
diploid
40
Name two things that make meiosis different from mitosis
-two cytokinesis events -homologous pairs line up during metaphase
41
whats wrong with the chromosomes if you have turners syndrome?
you are missing an X, you have XO
42
What happens in translocation?
a chromosome fragment attaches to a nonhomologous chromosome
43
What are autosomes?
the first 22 pairs of chromosomes
44
What is interphase?
the first three stages of the cell cycle
45
What happens during the second growth (G2) phase in the cell cycle?
Preparations are made foe the nucleus to divide. The organelle and membrane copies
46
What happens in anaphase?
centromeres divide. chromatids move toward opposite poles as the spindle fibers attached to them shorten
47
describe the process of spermatogenesis.
1. starts with a cell called spermatogonia. 2. spermatogonia chromosomes replicate to form a primary spermatocyte. 3. the primary spermatocyte splits to become secondary spermatocyte. 4. the secondary spermatocyte splits to form a total of four spermatids. 5. spermatids develop into sperm after developing a tail
48
Which cells are diploid?
somatic cells
49
which cells are haploid?
sperm and ova
50
What is a zygote?
a fertilized egg
51
How many pairs of chromosomes do humans have?
23
52
What is wrong with the chromosome if you have klinefelters
you have an extra X, XXY
53
what is wrong with the chromosomes if you have down syndrome
you have 3 #21 chromosomes
54
what is random fertilization?
is when a zygote that forms at fertilization is random (any sperm and egg)
55
what is independent assortment?
random distribution of homologous chromosomes during meiosis
56
What is a sex chromosome?
the 23rd pair of chromosomes that determines the sex of an idividual
57
describe anaphase I
homologous chromosomes to the opposite poles of the cell
58
What are gametes?
organisms reproductive cells
59
What are the end products of meiosis?
unique haploid gametes
60
what are the phases of mitosis, in order?
prophase, metaphase, anaphase, telophase
61
Why does meiosis produce four sperm cells but only one egg?
In sperm formation the cytoplasm divides equally in meiosis I and II to form four sperm cells. In egg formation the cytoplasm divides unevenly after meiosis I which causes one egg and three polar bodies
62
How many chromosomes do humans have?
46
63
what are chromatids?
two parts of a chromosome that contain identical copies of DNA and is joined by a centromere
64
What is genetic recombination?
the exchange of genetic information in order to increase the genetic diversity of the population
65
describe metaphase II
chromosomes line up along the equator
66
Define mutations
changes in an organism's chromosomes
67
What is the symbol for diploid?
2n
68
what happens in prophase?
the chromosomes coil up and become visible. Nuclear envelope dissolves and the spindle forms
69
What is a centromere?
the point at which the two chromatids of a chromosomes are attached
70
What happens in cytokinesis during the cell cycle?
cytoplasm divides
71
What happens during the synthesis (S) phase of the cell cycle?
DNA is copied
72
sperm and ova are \_\_\_\_\_cells
haploid
73
What happens in telophase?
Nuclear envelope forms at each pole. chromosomes uncoil, spindle dissolves and cytokinesis begins
74
Whats the difference between meiosis I and meiosis II.
meiosis I involves the separation of pairs of homologous chromosomes. meiosis II involves the separation of the two chromatids that make up each chromosome.
75
During cytokinesis in animal cells, the cell is pinched in half by \_\_\_\_\_\_\_
a belt of proteins
76
What are chromosomes?
rod-shaped structures made up of DNA wrapped tightly around proteins
77
What does diploid mean?
having two sets of chromosomes
78
what are the first 22 pairs of chromosomes called?
autosomes
79
what are somatic cells?
all the cells in your body except reproductive cells
80
when does spermatogenesis take place?
in a guys testicles when he hits puberty
81
What happens during mitosis?
nucleus divides into two nuclei
82
describe the process of oogenesis
1. the oogonia chromosomes replicate to form the primary oocyte. 2. the primary oocyte splits unevenly into two cells: the secondary oocyte and a polar body. 3. the secondary oocyte then splits unevenly to form an ovum and another polar body. 4. The ovum is the egg and the polar bodies die and disintegrate.
83
three 21 chromosomes means
you have down syndrome
84
What is cancer?
the untcontrolled growth of cells
85
what is oogenesis?
the formation of eggs
86
What is the difference between undifferentiated sperm cells and sperm?
undifferentiated sperm are made by meiosis. These cells become sperm by changing in form and developing tails
87
What re the end products of mitosis?
identical diploid cells
88
During cell division the DNA in a eukaryotic cell's nucleus is coiled into structures called \_\_\_\_.
chromosomes
89
What happens in deletion?
a piece of chromosome breaks off
90
Name four differences between mitosis and meiosis.
The purpose: mitosis-make identical copies of mother cell. meiosis-make genetically unique gametes. The end products; mitosis- identical diploid cells meiosis- unique haploid gametes In meiosis homologous pairs line up during metaphase and there are two cytokinesis events
91
describe telephase II and cytokinesis
-a nuclear envelope forms around each set of chromosomes. -the cytoplasm divides
92
If you are missing an X you have
Turners syndrome
93
what does haploid mean?
having one set of chromosomes
94
Name the for types of mutations
deletion, duplication, inversion, translocation
95
What has only one circular chromosome?
a prokaryote cell, bacteria
96
What happens in metaphase?
Chromosomes move to the center of the cell and line up along the equator
