Cell Cycle Flashcards

1
Q

In human cells, there are ___ chromosomes

A

46

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2
Q

There are ___ homologous pairs, called the autosomes

A

22

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3
Q

There are ___ sex chromosomes

A

2

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4
Q

___ is the female sex chromosomes

A

XX

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5
Q

___ is the male sex chromosomes

A

XY

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6
Q

Germ cells or sex cells consist of __ & __?

A

Sperm &

Oocyte (ovum)

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7
Q

Non-germ cells are called?

A

Somatic cells

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8
Q

The sequence of events that controls cell growth and division is called?

A

Cell cycle

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9
Q

The period of time it takes for a cell to complete one cell division is called?

A

Cell cycle

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10
Q

The cell cycle is divided into four phases namely?

A

G0
Gap 1(G1)
Synthesis (S)
Gap 2(G2)

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11
Q

How many checkpoints are in the cell cycle?

A

Three

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12
Q

The G1/S checkpoint ensures?

A

Cell nutrition, size and environment are favourable

DNA is intact

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13
Q

G2/M checkpoint ensures?

A

DNA is completely replicated

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14
Q

Metaphase/Anaphase checkpoint ensures?

A

DNA is intact

Chromosomes are attached to the mitotic spindle

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15
Q

The G1/S checkpoint prepares for?

A

DNA replication and entering of S phase

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16
Q

G2/M checkpoint prepares the cell for?

A

Mitosis

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17
Q

Metaphase/Anaphase checkpoint prepares?

A

Cytokinesis

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18
Q

G1, S & G2 phases are collectively referred to as?

A

Interface

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19
Q

Three characteristics of G1 phase are?

A

Longest part of the cycle
Active RNA & protein synthesis
Cell volume is restored to its original size

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20
Q

Three properties of S phase are?

A

DNA replication
Histone synthesis
Centrosome duplication

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21
Q

One property of G2 phase is?

A

Proteins required for mitosis accumulate

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22
Q

Three properties of G0 phase are?

A

Prolonged non-dividing phase
Differentiated & specialized cells
Temporarily or permanently suspended cell cycle activities

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23
Q

The cell cycle checkpoints are regulated by cytoplasmic proteins called?

A

Cyclins

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24
Q

Cyclins activate?

A

Cyclin-dependent kinases(CDK’s)

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25
Q

CDK’s initiate/induce progression through the?

A

Cell cycle

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26
Q

Progression through the cell cycle is halted by adverse conditions like?

A

Inadequate nutrition
Inappropriate cellular microenvironments
DNA damage

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27
Q

Somatic reproduction of cells is called?

A

Mitosis

28
Q

Mitosis includes?

A

Segregation of replicated chromosomes
Nucleus division(karyokinesis)
Cytoplasm division (cytokinesis)
Production of two identical daughter cells

29
Q

The events of mitosis are subdivided into 5 major stages namely

A
Prophase
Prometaphase
Metaphase
Anaphase
Telophase
30
Q

In prophase?

A

Centrioles move apart
Spindle forms
Nucleolus disappears
Kinetochores develop at centromeres of each chromatid

31
Q

In prometaphase?

A

Mitotic spindle moves into nuclear area
Nuclear membrane disappears
Each duplicated chromosome becomes attached at the kinetochore

32
Q

In metaphase?

A

Chromosomes condense further
Kinetochores at each centromere attach to the mitotic spindle
Chromosomes align themselves at the cell equator

33
Q

In Anaphase?

A

Spindle poles move further move apart
Microtubules lengths changes
Sister chromatids separate and are pulled towards opposite spindle poles

34
Q

In telophase?

A

Nuclear membrane forms
Centrioles duplicate
Nucleoli reappear
Chromosomes decondense

35
Q

Slowly dividing population of cells that serve to renew the differentiated cells of tissues are called?

A

Stem cells

36
Q

Stem cells divide ___?

A

Asymmetrically

37
Q

Stem cells produce one cell that remains as a ____ and another cell that differentiates into a ____

A

Stem cell

Progenitor cell

38
Q

Progenitor cells are also called?

A

Transit amplifying cells

39
Q

Embryonic stem cells are theoretically?

A

Totipotent(able to differentiate into any other cell type)

40
Q

Stem cells found in adults are either____ or ____

A

Multipotent(produce cells of several lineages) Eg multipotent haematopoietic stem cells produce all blood formed elements
Unipotent( produce a single cell type) eg unipotent epidermal stem cells produce epithelial cells

41
Q

A special form of cell division in germ cells in which the chromosome number is reduced from Diploid (2n) to haploid (n) is called?

A

Meiosis

42
Q

Meiosis involves two successive cell divisions namely?

A

Meiosis 1

Meiosis 2

43
Q

The cell resulting from meiosis differs from other cells in?

A

Number of chromosomes is reduced to half

Genetic information isn’t identical

44
Q

Prophase 1 is divided into 5 stages namely?

A
Leptotene
Zygotene
Pachytene
Diplotene
Diakinesis
45
Q

In prophase 1?

A

Chromatin condenses into visible chromosomes
Each chromosome consists of two chromatids joined at the centromere
Homologous maternal and paternal chromosomes pair form a tetrad
Nucleolus and nuclear envelope disappear
Crossing over occurs at the chiasmata

46
Q

The random exchange of genes between homologous chromosome segments is called?

A

Crossing over

47
Q

In metaphase 1?

A

Homologous pairs of chromosomes align at the cell equator

Spindle fibers from either pole attach to the kinetochore of any one of the chromosome pairs

48
Q

In Anaphase 1?

A

Chromosomes migrate to poles

Chromatids separate

49
Q

In telophase 1?

A

Nuclear envelope is re-established
Two daughter cells are formed
Each daughter cell contains 23 chromosomes (n)
Each chromosome is composed of two similar sister chromatids not genetically identical

50
Q

Meiosis 2 properties are?

A

A brief interphase without DNA replication (no S phase)

Two daughter cells divide producing four daughter cells each with its own recombined genetic material

51
Q

Mitosis has ____ of homologous chromosomes, meiosis has ____ of homologous chromosomes

A

no pairing

pairing

52
Q

Mitosis occurs in only _____organisms, while meiosis occurs in _______of humans, animals, plants & fungi

A

All

Reproductive cells

53
Q

Mitosis has only _____ cell division, meiosis has ____

A

One

Two

54
Q

Mitosis has ____ diploid daughter cells, meiosis has ____ haploid cells

A

two

four

55
Q

Mitosis reproduction type is _____ , meiosis is _____

A

asexual

sexual

56
Q

Crossing over ____ in mitosis, crossing over ____ in meiosis

A

doesn’t occur

occurs

57
Q

Mitosis produces _____ organisms or cells, meiosis produces _____ organisms or cells

A

identical

different

58
Q

N + 1 = 24 and N - 1 =22 This describes a condition where members of a pair fail to separate resulting in one daughter cell having an extra chromosome and the other daughter cell at the opposite pole minus a chromosome. This is known as?

A

Nondisjunction of chromosomes

59
Q

The resulting zygote upon fertilization with a normal gamete containing 23 chromosomes will have either____ or____

A
47 chromosomes (trisomy for that extra chromosome)
45 chromosomes (monosomy for the missing chromosome)
60
Q

Which Chromosomes are usually affected by chromosome nondisjunction?

A
8
9
13
18
21
61
Q

Defects caused by chromosome nondisjunction are?

A
Down syndrome(trisomy 21)
Klinefelter syndrome(XXY)
62
Q

Down syndrome(trisomy 21) is characterized by?

A

Mental retardation
Short stature
Congenital heart malformations

63
Q

Klinefelter syndrome(XXY) is characterized by?

A

Infertility
Variable degrees of masculinazation
Small testes

64
Q

The presence of an abnormal number of chromosomes in a cell is called?

A

Aneuploidy

65
Q

The process of pairing and ordering all the chromosomes of an organism, thus providing a genome-wide snapshot of an individual’s chromosomes is called?

A

Karyotyping

66
Q

The chromosome characteristics of an individual cell is known as?

A

Karyotype

67
Q

Karyotypes provide information about the___&___ of an organisms chromosomes

A

Number

Morphology