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An important facility for 9th class students preparing for short questions biology 9th class chapter 5 of BISE. Get hundreds of questions to prepare and get better marks in 9th biology
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Question: 1
Define Cell cycle.
Answer: 1
1-131
The series of events occurring in cell from time cell is produced until it completes mitosis and produces new cells. It has 2 phase. Interphase, Mitotic phase
Question: 2
What is metastasis? Write its role in cancer.
Answer: 2
2-131
The process, in which malignant cells send the cancer cells to other parts of body
Question: 3
Differentiate mitosis and Meiosis.
Answer: 3
3-131
Mitosis:i .It takes place in somatic cells. ii. It results in two duaughter cells. iii. No crossing over takes place. iv. No of chromosome remain same as parent cell
Question: 4
What is S-phase?
Answer: 4
4-131
In this phase, cell duplicates its chromosomes. As a result each chromosome consists of two sister chromatids
Question: 5
What is metaphase plate?
Answer: 5
5-131
The chromosomes arrange in cell equator and form a plate called as metaphase plate.
Question: 6
What is synapsis?
Answer: 6
6-131
The homologous chromosomes line up with each other and form pairs by process called synapsis
Question: 7
Describe G1 phase.
Answer: 7
7-131
After production, cell starts cell cycle with G1 phase. During Gq1, cell increases its supply of proteins, increases number of its organelles and grow in size. This is marked by synthesis of enzymes which are required in next place.
Question: 8
What is S-phase in cell cycle ?
Answer: 8
8-131
In S-phase cell duplicated its chromosomes .As a result each chromosomes consist of two sister chromatids.
Question: 9
What is crossing over? Give its one benefit
Answer: 9
9-131
Crossing over. The non-sister chromatids of hmologous chromosomes exchange their segments and teh phenomenon is known as crossing over. Benefit. It is the main source of variations. 2. It is necessary to maintain no of chromosome in next generation.
Question: 10
Write characteristic features of telophase II.
Answer: 10
10-131
Telophase II is marked with uncoiling and disappearance of chromosomes ,Nuclear envelop reform, cleavage or cell wall formation eventually produce a total 4 daughter cells each with haploid set of chromosome.
Question: 11
Define Meiosis.
Answer: 11
11-131
Meiosis is the process by which one diploid eukaryotic cell divide to generate four haploid daughter cells. It usually happens during gamete formation.
Question: 12
Differentiate between diploid and Haploid cells.
Answer: 12
12-131
Diploid: It means the cells in which chromosomes are in pairs. Example: in somatic cells.
Question: 13
What is difference between inter phase and inter phases II.
Answer: 13
13-131
Inter phase: Inter phase has 8 phase to duplicate chromosomes.
Question: 14
What is interphase?
Answer: 14
14-131
The time when a cell's metabolic activity is very high is called interphase. It has 3 phase G1 Phase , G2 phase, S-Phase
Question: 15
What is meant by Phragmoplast ?
Answer: 15
15-131
Cytokinesis in plant cells occur differently. Vesicles derived from the Golgi apparatus move to the middle of cells and fuse to form a membranous disk this disk is known as phragmoplast
Question: 16
State cytokinesis.
Answer: 16
16-131
Cytokinesis the division of cytoplasm is called cytokinesis
Question: 17
S-Phase of interphase is important and cell can never divide without it justify.
Answer: 17
17-131
In S-phase the cell duplicates its chromosomes the DNA molecules of each chromosome is copied and new protein molecules are attached the result is that each chromosome consists of two sister chromatids, which contains identical genes. In the absence of a S-Phase no replication of DNA will result in absence of chromosomes with two sister chromatids . Hence cell division will not occur
Question: 18
When and who discoverd the process of mitosis ?
Answer: 18
18-131
In 1880's , a germen biologist walther Flemming observed that in a dividing cell nucleus passes through a series of change which he called mitosis
Question: 19
What is binary fission?
Answer: 19
19-131
It is a process in which one organism divide into two organism
Question: 20
Define Mitotic phase ?
Answer: 20
20-131
It is short phase of cell cycle . during Mitotic phase, cell undergoes division to produce daughter cells.
Question: 21
What is meant by tumors?
Answer: 21
21-131
Sometimes mutation occur in such genes and cells continue to divide it results in growth of abnormal cells called tumors.
Question: 22
What is benign tumors.
Answer: 22
22-131
Benign tumors as long as these tumors remain in their original location, they are called benign tumors.
Question: 23
Differentiate between somatic cell germ cell ?
Answer: 23
23-131
Somatic Cell:
  1. Somatic cell are those which form the body of organisms.
  2. Somatic cell undergo mitosis
Question: 24
What is G2 phase ?
Answer: 24
24-131
in G2 phase cell prepare protein that are essential for mitosis, mainly for the production of spindle fibers.
Question: 25
Define Chiasmata.
Answer: 25
25-131
Chiasmata: During meiosis the two non -sister chromatids of homologous chromosomes join each other at certain points along their length. These points of attachment are called chiasmata.
Question: 26
Define alternation of generation ?
Answer: 26
26-131
  1. Plants show alternation of generation in their life cycle.
  2. diploid sporophyte generation undergoes meiosis and form haploid spores which grow to produce haploid gemetophyte generation
Question: 27
Define Reproduction.
Answer: 27
27-131
Reproduction: Reproduction is a biological process by which living things produce the individuals of the same species, i.e. the next generation of species. The most basic characteristics of life is "reproduction " reproduction occurs at different levels of organization .Parts of cell such as chromosomes produce new chromosomes, cells produce new cells this all involves in reproduction..
Question: 28
Define Anabolism ?
Answer: 28
28-131
Anabolism include all those biochemical reaction in which large molecule are formed from small molecules. Energy is used in anabolism.
Question: 29
Write type of Reproduction ?
Answer: 29
29-131
  1. Asexual Reproduction
  2. Sexual Reproduction
Question: 30
How is mitosis significant?
Answer: 30
30-131
Importance of mitosis is the maintenance of chromosomal set i.e. each daughter cell receives chromosomes that are alike in composition and equal in number to the chromosome of parent cell. During the occasions of development and growth, cell replacement, regeneration and asexual reproduction, mitosis happens.
Question: 31
DEfine Mitosis. Give its one benefit.
Answer: 31
31-131
Mitosis is a type of cell division in which a cell divides into two daughter cells. Each with the same number of chromosomes as was present in parent cell. Benefit. Importance of mitosis is the maintenance of chromosome set i.e. each daughter cell receives chromosomes that are alike in composition and equal in number to the chromosomes of parent cell.
Question: 32
How cytokinesis occur ?
Answer: 32
32-131
cytokinesis in plant cell occurs differently. Vesicles derived from the Golgi apparatus membrane-bonded disc called the cell plate or phragmoplates
Question: 33
Define Chromatin ?
Answer: 33
33-131
Chromatin is the hereditary material in the nucleus in the form of loose, thread like form. it is present normally when cell is not diving
Question: 34
How is metaphase plate formed ?
Answer: 34
34-131
Chromosomes arrange themselves at the equator region in metaphase of karyokinesis division of mitosis and hence forms metaphase plate
Question: 35
Define cell replacement ?
Answer: 35
35-131
New cell are formed by the mitosis and so are exact copies of the cell being replaced.Red blood cells have short life span and new red blood cells are formed by mitosis
Question: 36
Give name of phases of mitosis ?
Answer: 36
36-131
  1. Karyokinesis
  2. Cytokinesis
Question: 37
What is Anaphase?
Answer: 37
37-131
When a rinetochorespindle fiber connects with the rinetochre of chromosomes. It starts to pull toward the originatingcentrosomes.
Question: 38
Define Synapsis ?
Answer: 38
38-131
During prophase 1 of Meiosis 1 homologous chromosomes line up with each other and form pairs by process called Synapsis.
Question: 39
Define Mitotic spindle ?
Answer: 39
39-131
In prophase centrosomes give rise microtubules by joining tubulin proteins present in cytoplasm
Question: 40
Name the phases of karyokinesis?
Answer: 40
40-131
  1. Prophase
  2. Metaphase
  3. Anaphase
  4. Telophase
Question: 41
Define S-shape ?
Answer: 41
41-131
In S-shape cell duplicated its chromosomes.As a result each chromosome consists of two sister chromatids
Question: 42
What is mitosis?
Answer: 42
42-131
Mitosis is the type of cells division in which a cell divides into two daughter cells, each with the same number of chromosomes as were presents in parent cell
Question: 43
Differentiate diploid and haploid cell ?
Answer: 43
43-131
  1. Diploid (2n) means the cell in which chromosomes are in pairs
  2. While haploid (n) means the cells with half number of chromosomes i.e.chromosomes are not in the form of pairs
Question: 44
How are spindle fibers formed during prophase of mitosis?
Answer: 44
44-131
In prophase, Centrosomes give rise to microtubules by joining tubulin proteins present in cytoplasm the microtubles thus formed are called spindle fibers
Question: 45
Name two phases of cell cycle ?
Answer: 45
45-131
  1. Interphase
  2. Mitotic phase or M-phase
Question: 46
What is the role of mitosis in development and growth ?
Answer: 46
46-131
Importance of mitosis is the maintenan of chromosornal set. The number of cell within an organisms increased by mitosis.
Question: 47
What is Meiosis
Answer: 47
47-131
Meiosis is the process by which one diploid eukaryotic cell divides to generate four haploid daughter cells
Question: 48
Plant do not make their gametes by meiosis.Why ?
Answer: 48
48-131
Plant do not make their gametes by meiosis because plant gametes are already haploid (n)
Question: 49
Define Homologous chromosomes:
Answer: 49
49-131
A pair of chromosomes having the same size and shape and carrying alleles for the same traits
Question: 50
What is tumors ?
Answer: 50
50-131
Tumors are abnormal cell which grow due to abnormal division of cell .
Question: 51
Describe Asexual reproduction in hydra :
Asexual reproduction in hydra takes place through budding.
Answer: 51
51-131
During Budding, Cell on the surface of body of hydra undergoes mitosis and a cluster of cell are formed called bud
Question: 52
What is benign tumor ?
Answer: 52
52-131
If tumors remain in their original location for a long time they are called benign tumors
Question: 53
Why are tumors dangerous for human body ?
Answer: 53
53-131
Tumors become dangerous for human body when they attack on others tissues of the body Such tumors are called malignant or cancerous tumors
Question: 54
What is regeneration ?
Answer: 54
54-131
Some organisms can be regenerate part of their bodies the production of new cell is achieved by mitosis like sea star regenerates its lost part by the regeneration
Question: 55
Define Meiosis ? Which biologist discover meiosis ?
Answer: 55
55-131
Meiosis:Meiosis is a process in which a Eukaryotic diploid cell divided and forms four haploid
Discover:Meiosis was discovered and described for the first time in 1816 by a German biologist Oscar Hertwig
Question: 56
Define Metastasis
Answer: 56
56-131
Such tumor scanssend cancer cells to other plants in body where new tumor may form This phenomenon is called metastasis.
Question: 57
Define Chiasmata ?
Answer: 57
57-131
Chiasmata are formed during the prophase-I of meiosis-I these are the point attachment between non-sister chromatids of homologous chromosomes
Question: 58
What changes are placed in telophase I during meiosis?
Answer: 58
58-131
In telophase I Chromosomes arrive at the pole.Each pole now has half the number of chromosomes But each chromosomes still consists of two chromatids
Question: 59
Differentiate between interphase and mitotic phase
Answer: 59
59-131
Interphase: Interphase is the phase between two consecutive mitotic phase During interphase metabolic activities of cell rises Interphase is further divided into three steps
G1-phase , S-phase, G2phase
Question: 60
Write significance of meiosis in term of variation in organisms ?
Answer: 60
60-131
  1. The chromosomes pairs of each parent under go Crossing over during meiosis.So daughter cells i.e.gametes have genetic variation
  2. When gametes fuse and form zygote, its genetic make up is different form both parent
Question: 61
Define karyokinisi?
Answer: 61
61-131
Karyokinsis the division of nucleus is further divided into few phase parophasemetaphorsamorphousand telopase
Question: 62
What is kinetochore?
Answer: 62
62-131
Each chromosome has kinetochore at centromer kinetochore is a complex protein structure that is the point where spindle fibers attach.
Question: 63
When and who discoverd crossing over in drosophilla melanogaster ?
Answer: 63
63-131
In 1911 the american geneticist Thomas Hunt Morgan discoverd the phenomenon of crossing over in fruit by drosophilla melanogaster
Question: 64
What is difference phase
Answer: 64
64-131
The process of mitosis is complex and highly regulaed. there are two major phases the division of nucleus known karyokinesis and the division of cytokinesis.
Question: 65
What is interphase?
Answer: 65
65-131
interphase is the time when a cell's metabolic activity as very high as it perform its various function
Question: 66
What is necrosis ?
Answer: 66
66-131
The accidental death of cell and tissues is called necrosis.
Question: 67
Define Regeneration?
Answer: 67
67-131
Some organisms can regenerate points of their bodies the production of new cell is achieved by mitosis, For example sea star regenerates its last arm through mitosis
Question: 68
Define Crossing Over ?
Answer: 68
68-131
The exchange of segments between the non-sister chromatids of homologous chromosomes during meiosis
Question: 69
What is meant by Cleavages furrow
Answer: 69
69-131
In animal cells cytokinesis occurs by process known as cleavage A cleavage furrow develops where the metaphase plate used to be The furrow deepens and eventually pinches the parent cell into two daughter cells
Question: 70
Define Apoptosis:
Answer: 70
70-131
Apoptosis :
Apoptosisis one of the main types of programmed cell death. cell shrinks and become rounded due to the breakdown of cytoskeletion by enzymes
Question: 71
Write two source of occurrence of necrosis ?
Answer: 71
71-131
  1. Injury
  2. Infection
  3. Cancer
Question: 72
Define malignant?
Answer: 72
72-131
They include other tissues they are called malignant tumors and their cells are called comers cells.
Question: 73
What is meant by G0 Phase
Answer: 73
73-131
In multicellular eukaryotes, cells enter g0 phase from G1 and stop dividing Some cells remain in G0 phase semi-permeable e.g some cells of liver and kidney Many cells do not enter Go and continue to divide throughout an organisms life, e.g epithelial cells
Question: 74
What is malignant tumor ?
Answer: 74
74-131
Malignant tumor can send the cancer cell to other prats in the body where new tumors may form. This phenomenon is called metastasis
Question: 75
Define Mitosis Which biologist discover Meossis
Answer: 75
75-131
A type of cell division which produce daughter cell identical to the parents
Question: 76
Define cytokinesis?
Answer: 76
76-131
The division of the cytoplasium after nuclear division
Question: 77
Write a significance of meosis?
Answer: 77
77-131
Important of meiosis the significant of meiosis for reproduction and inheritancewas described in 1890 by german biologist August weirman. He pointed out that meiosis was necessarynot only to maintain the number of chromosome in the next generation but also to produce in next generation.
Question: 78
Define Meiosis Which biologist discover Meiosis
Answer: 78
78-131
Meiosis: Meiosis is a process in which a Eukaryotic diploid cell divide and form four haploid cells
Question: 79
What is metaphase?
Answer: 79
79-131
When spindle fibers have grown to sufficientlength some spindlefibers known as fibrilsKinetochore attach with Kinetochare of chromosome
Question: 80
What is Disjunction ?
Answer: 80
80-131
During anaphase I chromosomes separate and go to opposite poles while during anaphase II sister chromosomes separate.
Question: 81
Differentiate between chromatin and chromosome
Answer: 81
81-131
Chromatin: Chromatin is the hereditary material in nucleus in the form of loose, thread like form It is present normally when cellis not dividing
Question: 82
What id budding?
Answer: 82
82-131
A types of asexual reproduction in which a bud develops as a small outgrowth ofparent's body and forms the new individual.
Question: 83
What is tumor and what are benign and malignant?
Answer: 83
83-131
sometimesamutation occurs in such genes and cells continued to divide. It results in grouth of abnormal cells called tumors. they invade other tissues they are called malignant.
Question: 84
What is phragmoplast
Answer: 84
84-131
Cytokinesis in plant cells occurs differently Vesicles derived from the Golgi apparatus move to the middle of cell and fuse to form a membranous disk This disk is known as cell plate or phragmoplast
Question: 85
What are the effects of errors in meiosis
Answer: 85
85-131
Disjunction: During anaphase chromosomes separate and go to opposite poles while during anaphase sister chromosomes separte It is called disjunction
Question: 86
Define phargmoplast?
Answer: 86
86-131
The pharmoplast is a plant cells specific structure that forms during late cytokinesisIt serves as a scaffold for cell plate assembly and subsequent
Question: 87
How is metaphase plate formed
Answer: 87
87-131
Chromosomes arrange themselves at the equator region in metaphase of Karyokinetic division of mitosis and hence form metaphase plate
Question: 88
Write the difference between apoptosis and necrosis
Answer: 88
88-131
Difference between apoptosis and necrosis is given below
Apoptosis: Apoptosis is one of the main types of programmed cell death
Apoptosis can occur when a cell is damaged or undergone stress conditions
Question: 89
Define mitosis
Answer: 89
89-131
Mitosis is the type of cells division in which a cell divides into two daughter cells, each with the same number of chromosomes as were present in parent cell
Question: 90
What is Mitotic Spindle
Answer: 90
90-131
In prophase, centrosomes give rise to microtubules by joining tubulin proteins present in cytoplasm The microtubules thus formed are called spindle fibers Complete set of spindle fibers is known as mitotic spindle
Question: 91
Differentiate diploid and Haploid cell
Answer: 91
91-131
Diploid means the cells in which chromosomes are in pairs homologous pairswhile haploid means the cells with half number of chromosomes i.e. chromosomes are not in the form of pairs
Question: 92
Define Telophase?
Answer: 92
92-131
Telophase is a reversal of praphase. Anew nuclear encelop forms around each other ser of seperaed chromosomes
Question: 93
What is the role of Lysosome in necrosis
Answer: 93
93-131
During necrosis there is a release of special enzymes from lysosomes Lysosomal enzymes break cellular components and may also be released outside cell to break surrounding cells Cells that die by necrosis may also release harmful chemicals that damage other cells
Question: 94
Define synapsis?
Answer: 94
94-131
A junction between a neuron and another cell transmits nerve impulse from one neuron to the next neuron of to effectorscell
Question: 95
Give the name of phases of mitosis
Answer: 95
95-131
There are two major phases of mitosis
Question: 96
Name two phases of cell cycle. Which phase in divide into three phases
Answer: 96
96-131
Phases of cell cycle: Interphase, Mitotic phase or m-phase
Question: 97
Why are tumors dangerous for human body
Answer: 97
97-131
Tumors become dangerous for human body when they attack on other tissues of the body Such tumors are called malignant or cancerous tumors Such tumors send cancerous cells to others parts of the body where they form new tumors This process of spreading of diseaase is called Metastasis
Question: 98
Define spindle?
Answer: 98
98-131
The microtubulesthus formed are called spindle fibres
Question: 99
What is Regeneration
Answer: 99
99-131
Regeneration: Some organisms can regenerate parts of their bodies The production of new cells is achieved by mitosis like sea star regenerates its lost part by regeneration
Question: 100
Write two sources of occurrence of necrosis
Answer: 100
100-131
Injury, Infection, Cancer
Question: 101
When and who discovered crossing over in Drosophila Melanogaster
Answer: 101
101-131
In 1911 the American geneticist Thomas Hunt Morgan discovered the phenomenon of crossing over in fruit fly Drosophila melanogaster
Question: 102
What is cell cycle?
Answer: 102
102-131
The Cell cycle is the series of events from the time a cell is produced untilit completes mitosis and produce new cell.
Question: 103
Explain briefly how asexual reproduction occurs in Hydra
Answer: 103
103-131
Asexual Reproduction in Hydra: Asexual reproduction in Hydra takes place through Budding
During Budding Cells on the surface of body of Hydra undergoes mitosis and a cluster of cells are formed called Bud
Mitosis continues in cells of bud and it increase in size to form a new Hydra
Question: 104
Define Synapsis
Answer: 104
104-131
During prophase of Meiosis homologous chromosomes line up with each other and form Paris by a process called Synapsis
Question: 105
Define alternation of generations
Answer: 105
105-131
Alternation of Generations: Plants show alternation generation in their life cycle Diploid sporophyte generation undergoes Meiosis and Diploid sporophyte generation
Gametophyte generation under go mitosis to form haploid gametes which unite to produce diploid zygote Zygote grows through mitosis into diploid sporophyte generation
Question: 106
Write types of Reproduction
Answer: 106
106-131
Asexual Reproduction
sexual Reproduction
Question: 107
Explain S-phase in cell cycle
Answer: 107
107-131
In S-phase, cell duplicates its chromosomes As a result each chromosome consists of two sister chromatids
Question: 108
When chiasmata are formed
Answer: 108
108-131
Chiasmata are formed during the Prophase of meiosis chromatids of homologous chromosomes
Question: 109
Define Belebs
Answer: 109
109-131
During apoptosis cell shrinks and becomes rounded due to the breakdown of cytoskeleton by enzymes Its chromatin undergoes condensation and nuclear envelope breaks in this way nucleus spread in the form of several discern chromatin bodies cell membrane makes irregular buds known as beds Bled's break off from the cell and are now called apoptotic bodies which are then phagocytosed by other cells
Question: 110
Define Mitosis and Mitotic Spindle
Answer: 110
110-131
Mitosis: Mitosis is the type of cells division in which a cell divides into two daughter cells each with the same number of chromosomes as were present in parent cell
Question: 111
Plant do not make their gametes by meiosis
Answer: 111
111-131
Plants do not make their gametes by meiosis because plants gametes are already haploid
Question: 112
What is kinetochore
Answer: 112
112-131
Each chromosome has kinetochore at centromere Kinetochore is a complex protein structure that is the point where spindle fibers attach
Question: 113
When and who discovered the process of Mitosis
Answer: 113
113-131
In 1880 a Germen biologist Walther Fleming observed that in a dividing cell nucleus passes through a series of changes which he called mitosis
Question: 114
What is the importance of Apoptosis
Answer: 114
114-131
Apoptosis can occur when a cell is damaged or undergoes stress conditions Apoptosis removes the damaged cell preventing it from getting further nutrients or to prevent the spread of infections
Apoptosis also gives advantages during development For a example during the formation of fingers the cells between them undergo apoptosis and the digits separates
Question: 115
Define cell cycle
Answer: 115
115-131
Anabolism Anabolism include all those biochemical reaction in which larger molecules are formed from smaller molecules Energy is used in anabolism
Question: 116
Differentiate between S phase and G2 phase
Answer: 116
116-131
The difference between S-phase and G2 phase is given below
S-phase In s-phase cell duplicates its chromosomes As a its chromosomes As a result each chromosome consists of two sister chromatids
Question: 117
How cytokinesis is different in plant cells as
Answer: 117
117-131
Cytokinesis in plants: Cytokinesis in plant cells occurs differently Vesicles derived from the Golgi aparatus move to the middle of the cell and fuse to form a phragmoplast The plate grows outward and more vesicle fuse with it Finally the membranes of the cell plate fuse with the plasma membrane and its contents join the parental cell wall The result is two daughter cells, each bounded by its own plasma membrane and cell wall
Question: 118
What is the role of mitosis in development and growth
Answer: 118
118-131
Importance of mitosis is the maintenance of chromosomal set The number of cells within an organism increased by mitosis This is the basis of the development of cellular body from a single cell like zygote and also the basic of the growth of multicellular body
Question: 119
What are benign and Malignant Tumors
Answer: 119
119-131
Benign tumor: If tumors remain in their original location for a log time they are called benign tumors
Question: 120
Write two significances of Mitosis
Answer: 120
120-131
Cell replacement: New cells are formed by mitosis and so are exact copies of the cells have short life span about months and new red blood cells are formed by mitosis
Question: 121
Name the phases of Karyokinesis
Answer: 121
121-131
Prophase, Metaphase, Anaphase, Telophase
Question: 122
What is meant by Metastasis
Answer: 122
122-131
Malignant tumors can send the cancer cells to other parts in the body where new tumors may form The phenomenon is called metastasis means spreading of diseases
Question: 123
Write difference between mitosis and meiosis
Answer: 123
123-131
Meiosis: Meiosis was discovered and described for the first time in 1816 by a German biologist Oscar HartwigIn this process of cell division One parent cell produce four daughter cellsDue to meiosis each daughter cell have half number of chromosomes as present in parent cellMeiosis takes place is germ cellsCrossing over and mutation takes place in this process
Question: 124
Define Crossing Over
Answer: 124
124-131
The exchange of segments between the non-sister chromatids of homologues chromosomes during meiosis
Question: 125
Define somatic cells
Answer: 125
125-131
Somatic cells are those which form the body of organismsSomatic cells undergo mitosis
Question: 126
What are tumors
Answer: 126
126-131
Tumors are abnormal cells which grow due to abnormal division of cells
Question: 127
Write significance of Meiosis in term of variation in organisms
Answer: 127
127-131
The chromosomes pairs of each parent undergo crossing over during meiosis So daughter cells i.e gametes have genetic variations
When gametes fuse and form zygote, its genetic make up is different from both parents Thus meiosis allows a species to bring variations in the next generations
Beneficial variations help organisms to adapt to the change in enviroment
Question: 128
What changes are placed in telophase I during meiosis
Answer: 128
128-131
In telophase I Chromosomes arrive at the poles Each pole now has half the number of chromosomes but each chromosome still consists of two chromatids The spindle network disappears and nuclear envelope is formed around each haploid set The chromosomes uncoil back into chromatin
Question: 129
Define Apoptosis
Answer: 129
129-131
Apoptosis is one of the main types of programmed cel death It occur when cell damaged or undergoes stress conditions
Question: 130
Write down function of chiasmata in crossing over process
Answer: 130
130-131
Chiasmata are point of attachments between non-sister chromatids of homologous chromosomes It is the first step for irregular exhange of chromosomal segments
Question: 131
What is necrosis
Answer: 131
131-131
Necrosis: The accidental death of cells and tissues is called Necrosis