Chapter 8 Flashcards
(245 cards)
1
Q
Does asexual reproduction create genetically identical or adverse offspring?
A
Identical
2
Q
Does sexual reproduction create genetically identical or adverse offspring?
A
Diverse
3
Q
When is asexual reproduction beneficial?
A
You don’t need a mate, it takes less time and energy.
4
Q
How is asexual reproduction bad?
A
More competition for resources and stable environment and no genetic diversity.
5
Q
What are three benefits of sexual reproduction?
A
Having genetic diversity, having genes to adapt, evolution occurs easier.
6
Q
What are some organisms that do asexual reproduction?
A
Bacteria, yeast, liver cells, starfish.
7
Q
What are chromosomes?
A
Condensed DNA when cell is dividing.
8
Q
What is chromatin?
A
Loose DNA when cell is not dividing.
9
Q
What is a gene?
A
A unit of heredity found on a certain place on a chromosome that codes for a certain product.
10
Q
What is DNA?
A
Your genetic blueprint.
11
Q
What are chromosomes, chromatin, and genes made of?
A
DNA and proteins.
12
Q
Where may they be found in the cell?
A
Nucleolus.
13
Q
How many chromosomes are found in a human body cell? How many strands of chromosomes?
A
46 chromosomes, 92 strands.
14
Q
How many genes can be found in a human cell?
A
Thousands
15
Q
What isthe information in genes used for?
A
Making proteins and enzymes, growth and development of a cell, protecting the organism from infection, and ensuring fidelity of offspring to the parent.
16
Q
Where do diploid cells come from?
A
2 haploid cells
17
Q
What are somatic cells?
A
Body cells
18
Q
Are somatic cells haploid or diploid?
A
Diploid
19
Q
What is the notation for diploid?
A
2n
20
Q
What are gametes?
A
Sex cells
21
Q
Are gametes haploid or diploid?
A
Haploid
22
Q
What is the notation for haploid?
A
1n
23
Q
What does n stand for?
A
Number of chromosomes
24
Q
What process do bacteria divide by?
A
Binary fission
25
How does binary fission work?
DNA replicates and a cell membrane forms between the 2 chromosomes, dividing them and forming 2 daughter cells.
26
In binary fission, are the 2 daughter cells genetically identical or diverse?
Identical
27
How many chromosomes do bacteria cells have?
1
28
Does the number of chromosomes correlate to the complexity of the organism?
No
29
Why are somatic cells diploid cells?
Because they have one set of chromosomes donated by each parent, resulting in TWO sets of chromosomes.
30
How is a zygote formed?
When two gametes combine through fertilization
31
What is the name for gametes found in males?
Sperm
32
What is the name for gametes found in females?
Egg/Ovaries
33
In humans, how many chromosomes are inherited from the mother? The father?
23 each
34
In humans, how many chromosomes are found in a gamete?
23 chromosomes.
35
After fertilization, will the resulting zygote be haploid or diploid?
Diploid
36
How many chromosomes are found in a human zygote?
46
37
The diploid number for a horse is 64. What is the haploid number?
32
38
How many chromosomes are in a horse gamete?
32
39
How many chromosomes are in a horse zygote?
64
40
What is the cell cycle?
A sequence of growth + division of a cell.
41
What does the cell cycle begin and end with?
1 parent cell, 2 daughter cells.
42
Is this an example of asexual or sexual reproduction?
Asexual
43
What are the three main stages of the eukaryotic cell cycle?
Interphase, Mitosis, Cytokinesis
44
Define interphase.
G1, G2, and S phase. Where DNA is replicated before mitosis. The cell contents are duplicated here.
45
Define Mitosis
separating of sister chromatids. Genetically identical daughter cells. Division of nucleus through PMAT.
46
Define Cytokinesis.
When the cytoplasm is dividing. Not part of mitosis.
47
What are the 4 sub-phases for interphase?
G0, G1, G2, and S phase.
48
Summarize G0 phase.
Normal cell functions, not dividing.
49
Summarize G1 phase.
Growth. Duplicating organelles + making proteins for mitosis.
50
Summarize S phase.
Synthesis phase. DNA replication. One set for each daughter cell.
51
Summarize G2 phase.
Growth. Replicating centrosomes.
52
What are centrosomes made up of?
2 centrioles.
53
When a cell is dividing, how many centrosomes and centrioles are present?
2 centrosomes and 4 centrioles.
54
Which 2 organells duplucate autonomously and separately from the rest of the cell cycle?
Mitochondria and Chloroplast
55
Why does the cell begin to make large amounts of proteins?
To fuel mitosis.
56
How many strands of DNA are present during the G1 phase in humans?
1 strand.
57
Are these cells n or 2n?
2n
58
How many strands of DNA are present during the S phase in humans?
1 strand, duplicated.
59
How many strands of DNA are present during the G2 phase in humans?
2 strands
60
What is a centromere?
Holds together 2 sister chromatids
61
What are sister chromatids?
Identical copies of each other produced during DNA replication
62
What is the purpose of checkpoints in the cell cycle?
To make sure the cell is okay to go onto the next phase.
63
What is the G1 checkpoint?
It cheks to make sure the cell has room to grow, and it checks for DNA damage.
64
The G1 checkpoint happens prior to what phase?
The S phase
65
Why must nutrients be available before more cells can be made?
Because the nutrients are needed for mitosis.
66
What is the G2 checkpoint?
It assesses DNA errors.
67
The G2 checkpoint happens prior to wha phase?
Mitotic phase.
68
How would a replication error in DNA affect the function of the new daughter cell?
The cell could be mutated and continue to produce the mutation, or the cell will program itself to die.
69
What is another word for the cell programing itself to die?
Apoptosis
70
What is the M checkpoint?
It checks for the spindle fivers attatched to the kinetochore.
71
The M checkpoint is prior to which phase?
Anaphase
72
If the cell fails these checkpoints after it has committed to divide, what will typically happen to the cell?
It will destroy itself.
73
Why would the cell go through such drastic measures to make sure mitosis occurs without error?
To make sure the daughter cells have the correct number of chromosomes.
74
What would happen if the cell did not divide properly and continued to pass the checkpoints, even when it should not pass?
The cells produced will have either 1 extra or 1 less chromosome, and they will be mutated.
75
What are growth factors?
Proteins that signal and communicate between the cells. They are needed to stimulate cell division.
76
What is Density Dependent?
Contact between cells inhibits further mitosis.
77
What is another name for density dependent?
Contact inhibition
78
Why would cells stop mitosing when they fill up a space?
Because the density is at full capacity, and there is no room to divide.
79
What term describes "cells must have an underlying surface on which to adhere in order to grow?"
Anchorage Dependent
80
What is mitosis?
Phase of the cell cycle where the nucleus divides.
81
What type of cellular reproduction is this?
Asexual
82
What are examples of cells that do NOT go through mitosis?
Sex cells, haploid cells, RBC, nerve cells, heart cells.
83
What are the 3 main functions of mitosis?
1) Growth + Development
2) Replacement of Cells
3) Asexual reproduction
84
What types of animal body cells have a fast rate of mitosis?
Skin cells
85
Does mitosis occur in somatic cells or gametes?
Somatic cells
86
What is the first stage of mitosis?
Prophase
87
What happens to DNA during prophase?
Chromatin form condenses into chromosomes.
88
What change has occured to the nuclear envelope? To the centrosomes?
The nuclear envelope and nucleolus start to disappear. The centrosomes start tp move to either pole of the cell.
89
What protein fivers attatch to the kinetochore proteins at the centromere of the chromosomes?
Spindle fibers
90
How many chromosomes are there in prophase? Sister chromatids?
46 chromosomes, 92 chromatids.
91
What is the second phase of mitosis?
Metaphase
92
What happens during metaphase?
The sister chromatids line up on the center of the cell.
93
What is the imaginary line called where the chromosomes line up in the center of the cell?
Metaphase plate.
94
What is guiding the chromosomes to the center?
Microtubules (spindle fibers)
95
Which phase is a checkpoint?
Metaphase.
96
What would happen if the chromosomes were not lined up in metaphase?
Cell may give time to correct, or mitosis continues with wrong numbers of chromosomes in each sell.
97
Would each new daughter cell have the correct number of chromosomes?
No.
98
How many chromosomes are there in metaphase? Sister Chromatids?
46 Chromosomes, 92 Chromatids
99
What is the third phase of mitosis?
Anaphase
100
What happens during anaphase?
The chromatids are separated and pulled to either pole of the cell.
101
What happens to the duplicated chromosomes? The sister chromatids?
The centromeres come apart and the chromatids are separated. They are now called chromosomes.
102
What protein 'fibers' pull the chromosomes?
spindle fibers.
103
How many chromosomes are there in anaphase? Sister chromatids?
92 chromosomes, 0 chromatids.
104
How many chromosomes are on either pole in anaphase?
46 on either pole
105
What is the last stage of mitosis called?
Telophase
106
What happens during telophase?
The cell starts to pinch off. The form of the nucleus starts to come back.
107
What is a notable characteristic of telophase?
Clevage furrow.
108
What is a clevage furrow?
Where daughter cells are pinching off.
109
What happens to chromosomes in telophase?
They uncondense back into chromatin.
110
What change occurs to the nuclear envelope in telophase?
The appearance of it reforms.
111
How many chromosomes are there in telophase?
92 (46 on either end)
112
What is Cytokenisis?
The division of the cytoplasm into two daughter cells.
113
Which 2 phases of mitosis does cytokenisis overlap with?
Anaphase and telophase.
114
How many chromosomes are there in cytokenisis?
46 (in each daughter cell)
115
Which phase of the cell cycle is the longest?
Interphase.
116
Are the new cells from mitosis haploid or diploid?
Diploid
117
Are the daughter cells genetically identical or diverse
Identical because everything was copied and distributed evenly.
118
What are cancer cells the result of?
Multiple DNA mutations
119
How would mutations on cell checkpoint genes contribute to cancer?
Because cancer replicates without limit, so it ignores checkpoints.
120
What is a tumor?
An abromal mass.
121
What is a benign tumor?
One that doesn't spread.
122
What is a malignant tumor?
One that spreads uncontrollably.
123
What is metastasis?
Spread of cancer cells.
124
What does it mean when a tumor has metastasized?
It has started to spread.
125
How do more aggressive cancers differ in terms of rate of mitosis?
They can break off and duplicate quickly in other places.
126
Does chemotherapy target cells with a slow or fast rate of mitosis?
Fast rate.
127
What is radiation and chemotherapy?
Radiation destroys cancer cells, and chemo is a drug that treats metastatic tumors. They disrupt the cell cycle.
128
What is meiosis?
Reduction division producing 4 haploid cells. Produces gametes
129
How many cell divisions occur in meiosis?
2
130
How many cell divisions occur in mitosis?
1
131
How many daughter cells are produced in mitosis?
2
132
Are daughter cells in mitosis haploid or diploid?
Diploid.
133
Are cells in mitosis identical?
Yes
134
How many gametes are produced from one parent cell in meiosis?
4
135
Are cells in meiosis haploid or diploid?
Haploid
136
Are cells in meiosis unique or identical?
Unique
137
Which cells do mitosis and meiosis occur?
Mitosis in somatic cells, meiosis in egg/testes.
138
How many pairs of chromosomes do diploid cells have?
23 pairs.
139
What are autosomal chromosomes?
Pairs of chromosomes that are common to men and women.
140
Which pair of chromosomes is different?
Sex chromosomes.
141
Which sex chromosomes do women have? Men?
XX, XY
142
What are homologous chromosomes?
Chromosomes in a matched pair. They can be copies or duplications. Each pair of chromosomes represents homologous chromosomes.
143
Are homologous chromosomes identical to each other?
No, but they are similar.
144
Are sex chromosomes always identical? Are they considered homologous?
They are not always identical, and they are considered homologous.
145
Why do gametes must only have one set of chromosomes?
Because when they fertilize, the zygote has a set from each parent to make all 46.
146
Hedgehogs have a diploid number of 90. How many chromosomes does a hedgehog zygote have?
90
147
In which phase is DNA duplicated?
In S phase of Interphase
148
Is there an interphase before meiosis i?
Yes
149
What happens in prophase I?
Replicated chromosomes condense, homologous pairs match up, crossing over occurs between homologous pairs, spindle forms, nuclear envelope disappears.
150
What are tetrads?
4 chromatids
151
What is the term used to describe what happens when homologous chromosomes pair up to form tetrads?
Synapsis
152
What is crossing over?
When homologous chromosomes exchange DNA segments, reuslting in non-identical chromatids.
153
What is the purpose of crossing over?
To create varation.
154
Why might crossing over be advantageous to the offspring?
Because it creates genetic variation
155
In prophase 1, how many duplicated chromosomes are present?
46 duplicated chromosomes
156
How many sister chromatids are present in prophase 1?
92
157
What happens in metaphase 1?
Paired homologous chromosomes (tetrads) align at the center of the cell.
158
How is the arrangement of chromosomes in metaphase 1 different from that of metaphase?
In metaphase 1, the tetrads are lined up, in metaphase, the sister chromatids are lined up.
159
In metaphase 1, how many duplicated chromosomes are present? Sister chromatids?
46, 92
160
What happens in anaphase 1?
Tetrads are split up and homologous pairs are pulled to either side of the cell.
161
Do centromeres separate in anaphase 1?
No, the centromeres and chromatids do not separate yet.
162
In anaphase 1, how many duplicated chromosomes are present? How many sister chromatids?
23 pairs on each side, 46 chromatids on either side.
163
What happens in telophase 1?
The number of chromosomes is now reduced by half. After this phase the cell is considered to be haploid.( only one set of chromosomes) Note however, that the chromosomes are still replicated, and the sister chromatids must still be separated during meiosis II.
164
In telophase 1, how many duplicated chromosomes are present? Sister chromatids?
23 chromosomes, 46 sister chromatids.
165
What happens in cytokenisis?
The cytoplasm and cell divide, resulting in haploid cells.
166
Are the chromosomes in cytokenisis duplicated or unduplicated?
Duplicated
167
Are tetrads present?
No.
168
Is there an interphase for meiosis II?
No
169
Why does meiosis II occur?
Because there is too much DNA in the haploid daughter cells
170
In prophase 2, how many duplicated chromosomes are present? Sister chromatids?
23, 46
171
How is prophase II different from prophase I?
Prophase II involves separation of sister chromatids, while prophase I involves the separation of homologous chromosomes.
172
How is the arrangement of chromosomes in metaphase II different than in metaphase I?
The chromosomes are no longer in tetrads
173
How is the arrangement of chromosomes in metaphase II different than in metaphase of mitosis?
The sister chromatids in metaphase II are crossed over.
174
In metaphase II, how many duplicated chromosomes are present? Sister chromatids?
23, 46
175
What happens in anaphase II?
The sister chromatids are finally separated.
176
How many duplicated chromosomes are present in anaphase II? Chromatids?
46 (23 either side), 0
177
How many haploid cells do the cells in telophase II divide into?
4
178
How many duplicated chromosomes are present in telophase II?
23 on each side
179
In the second cytokenisis of meiosis, how many chromosomes will be present in each resulting cell?
23
180
Are the resulting cells haploid or diploid?
Haploid
181
Are the chromosomes duplucated or unduplicated at the end of the second cytokenisis in meiosis?
Unduplicated
182
During which phase of meiosis are the homologous chromosomes separated?
Anaphase I
183
During which phase of meiosis are the sister chromatids separated?
Anaphase II
184
In a human cell, how many chromosomes does each daughter cell have after meiosis I?
46
185
In a human cell, how many chromosomes does each daughter cell have after meiosis II?
23
186
Describe why a person's siblings are genetically different from one another?
Because of crossing over in prophase I.
187
What are three purposes of meiosis?
To replace diploid cells with haploid cells, to make gametes, and to create genetic variation.
188
What are other sources of genetic variation?
Mutation, independent assortment
189
What is nondisjunction?
When a pair of homologous chromosomes or sister chromatids fails to separate evenly during meiosis.
190
Can nondisjunction occur in meiosis I and II?
Yes
191
If nondisjunction occurs in meiosis I, how many gametes with abnormal chromosomes would result?
4 abnormal. (2 n+1, 2 n-1)
192
If nondisjunction occurs in meiosis II, how many gametes with abnormal chromosomes would result?
2 abnormal
193
What is monosomy?
When a cell is missing a copy.
194
What is trisomy?
When a cell has an extra copy
195
What is a karyotype?
A magnified image of chromosomes taken in homologous pairsand put in order.
196
Which phase is used for karyotyping and why?
Metaphase because it is the most clearly visualized.
197
What is aneuploidy?
Identifying an abnormal number of chromosomes.
198
What is Trisomy 21?
Down Syndrome. Extra chromosome 21, so a total of 47 chromosomes. Symptoms are lower cognition and facial differences.
199
What is Klinefelter syndrome?
When male has extra X chromosome. XXY. More feminine, more breast tissue, smaller testicles, and often sterile.
200
What is Turner Syndrome?
Females missing an X chromosome. XO. 45 chromosomes total. Webbed neck, heart problems, short stacked.
201
What are Metafemales?
When females have an extra X chromosome. XXX. Appear normal, might have low muscle deficiency and learning disabilities.
202
What is Jacobs Syndrome?
Supermale. Males have an extra Y chromosome. XYY. They are taller and more aggressive.
203
Explain how sexual reproduction can result in genetic diversity.
Because the zygote has half the genetic material from each parent
204
Explain the two main roles cell division plays in continuing life.
Growth and repair, and replacement of old cells.
205
Describe the process of binary fission.
Binary fission is the process bacteria use to replicate themselves. DNA replicates and cell membrane forms between the two chromosomes, dividing them and forming 2 daughter cells.
206
What factors in eukaryotic cells make cell division more complex than in prokaryotic cells?
The structure of the nuclear envelope in eukaryotic cells is more advanced.
207
Distinguish the difference between chromosomes, genes, and DNA.
Chromosomes carry DNA (condensed), genes are segments of DNA that give you physical characteristics, and DNA is your genetic blueprint.
208
How do sister chromatids attach to one another?
With a centromere
209
When in cell division, how do sister chromatids separate?
In anaphase, they are pulled to either end of the cell by spindle fibers.
210
Is the DNA in sister chromatids always identical?
It is not, because in meiosis there is crossing over which makes them different.
211
Describe the phases and steps of the cell cycle leading to mitosis.
Before mitosis is the interphase, where DNA and organelles are duplicated and checkpoints are gone through to make sure the cell has the okay to carry out mitosis.
212
What must happen before cells can divide?
They must pass the checkpoints.
213
Describe cytokenisis.
Cytokinesis is when the cytoplasm separates in the 2 cells. Results in 2 diploid cells for mitosis, and 4 haploid cells in meiosis.
214
Define three main purposes for mitosis.
To grow and repair, replace old cells, and asexual reproduction.
215
Understand the stages of mitosis and what occurs at each phase.
Prophase: nuclear envelope disappearing, chromatin condensing into chromosomes, centrosomes moving to either end, spindle fiber formation.
Metaphase: sister chromatids move to center of cell on metaphase plate
Anaphase: centromeres broken, chromosomes move to either end of the cell.
Telophase: Clevage furrow emerges. Nuclear envelope reforming
216
Describe checkpoints. Where in the cell cycle do they occur?
Checkpoints are points within the cell cycle where the cell is checked to make sure it can undergo mitosis. G1 checkpoint happens before the S phase, G2 checkpoint happens before the mitotic phase, and M checkpoint happens before anaphase.
217
What role does mitosis play in cancer?
Cancer cells uncontrollably reproduce.
218
Describe homologous chromosome.
Homologous chromosomes are chromosome pairs. You get one from each parent, and they are similar but not identical.
219
Describe duplicated chromosome.
Duplicated chromosomes are when a single chromosome is duplicated and joined at the centromere. (identical)
220
Describe chromatid.
Chromatid is two identical chromosomes that split and contain the same genetic material.
221
Describe centromere
What holds together chromatids.
222
Describe tetrad
A paired set of homologous chromosomes, each containing 2 sister chromatids. (4 total)
223
Define the difference between autosome and sex chromosome.
Autosomal are chromosomes that are found in both men and women, and sex chromosomes are what determines the sex of offspring. (XX or XY).
224
Define diploid.
Diploid is a cell or organism that has paired chromosomes, one from each parent.
225
Define haploid.
When a cell has only one set of chromosomes.
226
Identify cells in humans that are haploid and diploid.
Diploid - somatic (body) cells. Haploid - gametes (sex cells)
227
Explain how mitosis and meiosis are different.
Mitosis produces genetically identical cells, whereas meiosis produces genetically diverse cells.
228
How many daughter cells does meiosis produce? Are they genetically identical?
Meiosis makes 4, and they are not identical.
229
Discuss events occuring during interphase of meiosis.
It is when there are checkpoints and DNA replication. Preparing the cell to divide.
230
Explain prophase I (synapsis, crossing over, formation of tetrads).
Prophase I is where homologous chromosomes pair up, tetrads form, crossing over (sharing DNA segments) happens.
231
Explain metaphase I
metaphase I is where tetrads line up on the center.
232
Explain anaphase I
When the tetrads are split and pulled to either end of the cell.
233
Explain telophase I
Chromosomes now reduced by half. Cell is now considered to be haploid. However, chromosomes are still replicated and sister chromatids need to be separated.
234
Explain prophase II
Each cell is haploid with chromosomes in replicated form
235
Explain metaphase II
Sister chromatids align in the center.
236
Explain anaphase II
Sister chromatids separated and pulled to either side
237
Explain telophase II
4 haploid cells starting to form, each with 23 chromosomes.
238
Cytokenisis II will result in how many daughter cells?
4 daughter cells.
239
Discuss the importance of crossing over.
It creates genetic variability in offspring.
240
Define nondisjunction.
Nondisjunction is an error of meiosis when a pair of homologous chromosomes or sister chromatids fails to separate evenly.
241
List some disorders that result from nondisjunction of chromosomes.
Trisomy 21, Jacob's, Kleinfelter, Metafemale, Turner Syndrome
242
Discuss the major sources of genetic variation.
Mutation, crossing over, independent assortment.
243
If an organism has 16 total chromosomes (diploid), state the haploid number, number of chromosome pairs, and number of chromosomes found in the zygote.
Haploid - 8
Pairs - 8 pairs
Zygote - 16 chromosomes
244
Discuss the sources of genetic variation that occur in meiosis. Describe crossing over, orientation, mutation, and fertilization in your own words.
Independent assortment: where homologous chromosomes are randomly distributed to separate poles during meiosis.
Crossing over: when homologous chromosomes pair up and exchange DNA segments.
245
Dscribe the different chromosome abnormalities, including the chromosome types and symptoms.
Trisomy 21: extra chromosome on 21. Slow cognition, facial differences.
Kelinfelters: XXY. Males are more feminine, more breast tissue, small testicles, sterile.
Jacob's: XYY. Males have extra Y. Taller, more aggressive.
Metafemale: XXX. Female has extra X. Low muscle deficiency, learning disability.
Turner: XO. Females missing and X. Webbed neck, short stature, heart problems. THE ONLY MONOSOMY (45 chromosomes)
