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Biology IB YR12-13 > D2.1 Cell & Nuclear Division > Flashcards

D2.1 Cell & Nuclear Division Flashcards

(74 cards)

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1
Q

what is the result of a single cell undergoing cycles of cell division

A

cells that make up a multicellular organism

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2
Q

parent cell

A

cell that divides to form daughter cells my mitosis or meiosis

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3
Q

daughter cell

A

cell produced when a parent cell undergoes cell division - mitosis or meiosis

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4
Q

what are the 2 types of cell division

A

mitosis and meiosis

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5
Q

cytokinesis

A

splitting of cytoplasm in a parent cell between daughters cells following division of nucleus

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6
Q

nuclear division

A

when the nucleus divides first during cell division

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7
Q

how does cytokinesis occur in animal cells

A

cleavage furrow is formed which separates daughter cells

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8
Q

where is a cleavage furrow formed

A

equator or centre of cell and pinches cell membrane together to split cytoplasm

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9
Q

when does a cleavage furrow form

A

when actin and myosin proteins form a contractile ring under plasma membrane

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10
Q

role of Golgi apparatus In cytokineses

A

forms vesicles of new cell wall materials which collect at equator or cell plate

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11
Q

how does cytokinesis occur in plant cells

A

when cell plate reaches cell wall of parent cell, new cell walls are produced

separates new daughter cells

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12
Q

what are cell plates formed off and what do they carry

A

formed of vesicles and carry carbohydrates

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13
Q

how is plasma membrane in daughter cell created

A

lipids and proteins fusing together

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14
Q

examples of unequal cytokinesis

A

oogenesis
spermatogenesis
budding in yeast

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15
Q

sizes of cytoplasm during cytokinesis

A

usually equal
with at least 1 mitochondria and 1 chloroplast

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16
Q

oogenisis definition

A

egg production in humans

one egg is formed as well as several small cells that don’t go forward with fertilisation

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17
Q

oocyte

A

immature egg cell - ovum

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18
Q

steps of oogenesis briefly

A

primary oocyte division to form one small polar body which is mainly just cytoplasm and a secondary oocyte which is the main one

division occurs again in both and total of 3 polar bodies and one ovum

polar bodies merge with ovum to form one big egg cell

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19
Q

why does ovum need a large cytoplasm

A

to provide nutrients and energy for the growing embryo

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20
Q

mitosis and meiosis purpose

A

division of nucleus of cell in eukaryotic cell

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21
Q

anucleate

A

cell without a nucleus

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22
Q

why is it important for nucleus of a cell to divide before cell division

A

to avoid production of anucleate cells

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23
Q

mitosis definition

A

daughter nuclei have the same number of chromosomes as the parent cell

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24
Q

what is mitosis used for

A

growth, repair of damaged tissues, replacement of cells and ASEXUAL reproduction

maintains chromosome number and genome of cells

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25
diploid
cells with nuclei containing 2 sets of chromosomes
26
cells produced in mitosis will be ----
diploid
27
meiosis definition
daughter cell containing half the number of chromosomes of the parent cell one chromosome of each parent present in nuclei
28
cells produced in meiosis will be ----
haploid
29
meiosis used
production of gametes - sperm and egg generating genetic diversity
30
haploid notation
n
31
diploid notion
2n
32
interphase definition
the period between the nuclear divisions replication of chromosomes takes place
33
phases in interphase
gap 1, gap 2, synthesis
34
chromatid
one of 2 copies of a chromosome after it has replicated, jointed together at centromere
35
centromere
constriction of chromosome, the region that becomes attached to the spindle fibres during nuclear division
36
condensation of chromosomes brief explanation
dna molecules are too long and need to fit in small nuclei they become condensed by supercoiling to form chromosomes
37
how does condensation of DNA occur
through repeated coiling of dna molecule
38
histone protein role
packages dna into nucleosomes
39
how is supercoiling aided
is aided in eukaryotic cells by histone protiens and enzymes
40
histone definition
protiens that forms the structure of chromosomes and is used in chromosome condensation to form nucleosomes
41
nucleosomes definition
basic unit of eukaryotic chromosome structure, consisting of a ball of 8 histone protein molecules wrapped about by 2 coils of DNA
42
supercoiling
form of DNA in which the double helix is further twisted about itself within nucleosomes. forming tightly coiled structure
43
how to chromosomes move during division
microtubules and microtubule motors move them
44
microtubules
tubular fibres that form part of the cytoskeleton of the cell lengthen and shorten in order to make the chromosomal movement
45
4 main phases of mitosis (PMAT)
prophase metaphase anaphase telophase
46
prophase simple
first stage where chromosomes condense centrosomes move towards opposite poles spindle fibres emerge from centrosomes nuclear membrane breaking down into smaller vesicles nucleolus dissapears
47
metaphase simple
centrosomes reach opposite poles spindle continue to extend chromosomes line at equator of spindle spindle fibres reach chromosome and attach to centrosomes - kinetochores each sister chromatid is attached to a spindle fibre originating from opposite poles
48
anaphase simple
sister chromatids separate at centre spindle fibres shorten chromosomes pulled to opposite poles by spindle fibres
49
telophase simple
chromosomes at opposite poles and start decondensing nuclear envelopes begin to reform around each set of chromosomes spindle fibres break down new nuclei form within each nucleus
50
meiosis phases
meiosis 1 and 2
51
what happens during m1
homologous pairs of chromosomes split to produce 2 haploid nucleus
52
how many chromatids in one chromosome
2
53
chromosome number in m1
halves from 2n to n in M1 -> reduction division
54
homologous chromosomes
pairs of chromosomes in a diploid organism that have similar genes, although not necessarily identical
55
bivalent
pair of homologous chromosomes held together by chiasma
56
chiasma
site of crossing over of segments of DNA between homologous chromosomes or non sister chromatids
57
crossing over
exchange of genetic material between bivalents occurs between non-sister chromatids results in a new combination of alleles on the 2 chromosomes
58
recombinant chromosomes
chromosomes which have been genetically changed due to crossing over
59
M2
between m1 and m2 no interphase during m2 - chromatids separate to produce 4 haploid nuclei each chromosome consists of a single chromatid
60
non disjunction occurs
occurs when chromosomes fail to separate correctly during meiosis can occur in anaphase 1 or 2
61
non disjunction leading to
gametes being formed with an abnormal number of chromosomes may end up with one extra copy of a particular chromosome or no copies of a particular chromosome
62
what happens if abnormal gametes are fertilised
chromosomes abnormality occurs as the diploid cell will have the incorrect numbers of chromosomes
63
example of non disjunction chromosome abnormality
Down syndrome or trisomy 21
64
what happens in Down syndrome
total of 47 chromosomes rather than 46 they have 3 copies of chromosome number 21
65
what is the impact of trisomy 21 or Down syndrome
varies between individuals common features - physical growth delays reduced intellectual ability issues with sight or hearing
66
where else can trisomy 21 occur
in chromosomes 18 and 13
67
non disjunction definition
the failure of homologous chromosomes or sister chromatids to separate properly during meiosis
68
down syndrome definition
a congenital condition in which a person has an extra chromosome 21 as a result of non disjunction
69
karyotyping definition
a process which makes a diagram (karyotype) of chromosomes descending in size
70
karyotyping use
can be used to identify chromosomal abnormalities
71
how is genetically different offspring advantageous
for natural selection increase in survival of species - evolving and adapting genetic variation in populations of sexually reproducing species
72
what causes genetic differentiation
crossing over mothers and fathers genes are exchanged into each others chromosomes
73
random orientation
orientation of bivalents when they line up at the cell equator (M1) determines which pole each chromosome gets attached to
74
combination formula
2^n

Biology IB YR12-13 (33 decks)

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